An Open-label Extension Study to Evaluate Long-term Efficacy and Safety of A4250 in Children With Progressive Familial Intrahepatic Cholestasis Types 1 and 2 (PEDFIC 2)
Phase: PHASE3
Conditions: Progressive Familial Intrahepatic Cholestasis
Sponsor: Albireo, an Ipsen Company

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
1 
 
 
 
CLINICAL STUDY PROTOCOL A4250-008 
An Open-label Extension Study to Evaluate Long-term Efficacy and Safety of A4250 in 
Children with Progressive Familial Intrahepatic Cholestasis Types 1 and 2 (PEDFIC 2) 
 
 
IND Number: 
130591 
EudraCT Number 
2017-002325-38 
 
Text Product: 
A4250 
 
Indication: 
Progressive Familial Intrahepatic Cholestasis (PFIC) 
 
Sponsor: 
Albireo AB 
 
Development Phase: 
Phase 3 
 
Sponsor Signatory: 
 Philip Stein, MD 
Sponsor Medical Monitor: 
 
Principal Investigator: 
Richard Thompson, MD, PhD 
Date of the Protocol: 
11 February 2022 
Version of the Protocol: 
Amendment 6.2 Sweden 
 
 
 
 
 
 
 
 
 
Confidential 
 
The information in this document contains trade secrets and commercial information that are privileged or 
confidential and may not be used, divulged, published, or otherwise disclosed without the written consent of 
Albireo AB. These restrictions on disclosure apply equally to all future information supplied to you or 
generated by you in connection with the study. 
PPD

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
2 
 
 
 
 
SPONSOR SIGNATURE PAGE 
PROTOCOL TITLE: An Open-label Extension Study to Evaluate Long-term Efficacy 
and Safety of A4250 in Children with Progressive Familial Intrahepatic Cholestasis 
Types 1 and 2 (PEDFIC 2) 
 
 
PROTOCOL NUMBER: A4250-008 
 
 
Albireo AB 
Date (day/month/year) 
PPD

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
3 
 
 
 
INVESTIGATOR SIGNATURE PAGE 
 
 
PROTOCOL TITLE: An Open-label Extension Study to Evaluate Long-term Efficacy 
and Safety of A4250 in Children with Progressive Familial Intrahepatic Cholestasis 
Types 1 and 2 (PEDFIC 2) 
 
 
PROTOCOL NUMBER: A4250-008 
I have read this protocol and agree that it contains all necessary details for performing this 
study. I will conduct the study as outlined herein and will complete the study within the time 
designated, in accordance with all stipulations of the protocol and in accordance with Good 
Clinical Practice (GCP), local regulatory requirements, and the Declaration of Helsinki. 
I will provide copies of the protocol and all pertinent information to all individuals responsible 
to me who assist in the conduct of this study. I will discuss this material with them to ensure 
that they are fully informed regarding the study drug and the conduct of the study. 
I will use only the informed consent approved by the Independent Ethics Committee 
(IEC)/Institutional Review Board (IRB) and will fulfil all responsibilities for submitting 
pertinent information to the IEC/IRB responsible for this study. 
I agree that the Sponsor (Albireo AB) shall have access to any source documents from which 
case report form information may have been generated. 
I further agree not to originate or use the name of Albireo AB or A4250 in any publicity, news 
release, or other public announcement, written or oral, whether to the public, press, or 
otherwise, relating to this protocol, to any amendment to the protocol, or to the performance of 
this protocol without the prior written consent of Albireo AB. 
 
 
 
 
 
Name of Investigator 
 
 
 
 
 
Signature 
Date (day/month/year) 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
4 
 
 
 
1 
ADMINISTRATIVE INFORMATION 
An Open-label Extension Study to Evaluate Long-term Efficacy and Safety of A4250 in 
Children with Progressive Familial Intrahepatic Cholestasis Types 1 and 2 (PEDFIC 2) 
Protocol No.: 
A4250-008 
Date of the initial Protocol: 
24 August 2017 
Date and Number of Amendment(s): 
Amendment 01, 18 April 2018 
Amendment 02, 18 January 2019 
Amendment 03, 11 March 2019 
Amendment 5.2 Sweden, 12 January 2021 
Amendment 6.2 Sweden, 11 February 2022 
Sponsor: 
Albireo AB 
Arvid Wallgrens Backe 20 
413 46 Göteborg 
Sweden 
Clinical Research Organization: 
ICON Clinical Research Ltd 
South County Business Park 
Leopardstown, Dublin 18, 
D18 X5R3 
Ireland 
Sponsor Signatory: 
Philip Stein, MD 
Albireo Pharma, Inc. 
10 Post Office Square, Suite 502 South 
Boston, MA 02109 
United States 
Tel 
 
Sponsor Medical Monitor: 
 
Tel 
 
Principal Investigator: 
Richard Thompson, MD, PhD 
SE5 9RS, London 
United Kingdom 
Tel
Fax
PPD
PPD
PPD
PPD
PPD

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
5 
 
 
 
2 
STUDY SYNOPSIS 
 
Name of Sponsor/Company: 
Albireo AB 
Name of Product: 
A4250 
Name of Active Ingredient: 
A4250 
Title of Study: 
An Open-label Extension Study to Evaluate Long-term Efficacy and Safety of A4250 in Children with 
Progressive Familial Intrahepatic Cholestasis Types 1 and 2 (PEDFIC 2) 
Principal Investigator: 
Richard Thompson, MD, PhD 
Study Centers: 
Up to 50 sites will be included in this study in the United States (US), Canada, Europe, Australia, and Middle 
East. 
Publication(s): 
None. 
Planned Study Period: 
Q3 2018 to Q3 2023 
Development Phase: 
Phase 3 
Objectives: 
Primary Objective (Cohort 1) 
To demonstrate a sustained effect of A4250 on serum bile acids and pruritus in children with progressive 
familial intrahepatic cholestasis (PFIC) Types 1 and 2. 
Primary Objective (Cohort 2) 
To evaluate the effect of A4250 on serum bile acids and pruritus in patients with PFIC who either (1) do not 
meet eligibility criteria for Study A4250-005 (PEDFIC 1) or (2) patients who do meet the eligibility criteria 
for Study A4250-005 after recruitment of Study A4250-005 has been completed. 
Secondary Objectives (Cohorts 1 and 2) 
To evaluate the long-term safety and tolerability of repeated daily doses of A4250 
To evaluate the effect of A4250 on growth 
To evaluate the effect of A4250 on biliary diversion and/or liver transplantation 
To evaluate the effect of A4250 on biochemical markers of cholestasis and liver disease 
Methodology: 
This is a Phase 3, multi-center, open-label extension study to investigate the long-term efficacy and safety of a 
120 µg/kg/day daily dose of A4250 in patients with PFIC, including episodic forms also referred to as benign 
recurrent intrahepatic cholestasis (BRIC). Cohort 1 will consist of children with PFIC Types 1 and 2 who have 
participated in study A4250-005. Cohort 2 will consist of approximately 60 patients with PFIC who have 
elevated serum bile acids and cholestatic pruritus and who either (1) do not meet eligibility criteria for Study 
A4250-005 (PEDFIC 1) or (2) are eligible for enrolment in A4250-005 after recruitment of study A4250-005 
has been completed. Up to 40 patients post biliary diversion surgery are allowed to participate in Cohort 2. 
Eligible patients will be enrolled into this open-label extension study and treated with a daily dose of 
40 µg/kg/day1 or 120 µg/kg/day of A4250 for 72 weeks, or 40 µg/kg/day for the first 12 weeks followed by 
120 µg/kg/day for the remaining 60 weeks1. Patients not tolerating the 120 µg/kg/day dose after a minimum 
of 1 week will have the option to down-titrate to a lower dose (40 µg/kg/day). The patient should return to 
the higher dose as soon as deemed appropriate by the investigator. More than one upward dose titration 
(from 40 µg/kg/day directly to 120 µg/kg/day) for the same event is not recommended. Any dose titration 
should be done in consultation with the sponsor Medical Monitor or designee. 
 
1 As of Protocol Amendment 6.2 Sweden, patients entering Cohort 2 will start treatment at 40 µg/kg/day 
with the possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus 
based on investigator judgment. 

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Confidential
Amendment 6.2 Sweden, 11 February 2022
6
Name of Sponsor/Company:
Albireo AB
Name of Product:
A4250
Name of Active Ingredient:
A4250
Number of Patients:
Approximately 120 patients in total. Approximately 60 patients will be enrolled following participation in 
Study A4250-005 (Cohort 1) and approximately 60 patients will be enrolled directly into this study (Cohort 2).
Diagnosis and Main Criteria for Inclusion:
Cohort 1:
1.
Completion
of
the 24-week
Treatment
Period
of
Study
A4250-005
or withdrawn from 
Study A4250-005 due to patient/caregiver judgment of intolerable symptoms after completing at least 
12 weeks of treatment. Patients who withdraw from A4250-005 due to a study drug related adverse 
event (AE) will not be eligible.
2.
Signed informed consent and assent as appropriate. Patients who turn 18 years of age (or legal age 
per country) during the study will be required to re-consent to remain on the study.
3.
Patients expected to have a consistent caregiver for the duration of the study.
4.
Caregivers (and age-appropriate patients) must be willing and able to use an electronic diary 
(eDiary) device as required by the study.
Cohort 2:
1.
A male or female patient of any age, with a clinical diagnosis of PFIC, including episodic forms 
(i.e., BRIC), and with a body weight 5 kg at Visit S-1.
2.
Patient must have clinical genetic confirmation of PFIC.
3.
Patients with PFIC, excluding BRIC, must have elevated serum bile acid concentration, specifically 
measured to be
at least 7 days apart (Visits S-1 and 
S-2) prior to the Screening/Inclusion Visit (Visit 1).
4.
Patients with PFIC, excluding BRIC, must have history of significant pruritus and a caregiver- 
reported observed scratching or patient-reported itching (for patients >18 with no caregiver-reported 
observed scratching) in the eDiar
the
Screening/Inclusion Visit (Visit 1).
5.
Patients with episodic forms of PFIC (i.e., BRIC) must have an emerging flare characterized by 
clinically significant pruritus and elevated serum bile acid levels/cholestasis as judged by the 
investigator.
6.
Patient and/or legal guardian must sign informed consent (and assent) as appropriate. Patients who 
turn 18 years of age (or legal age per country) during the study will be required to re-consent in 
order to remain in the study.
7.
Age-appropriate patients are expected to have a consistent caregiver for the duration of the study.
8.
Caregivers and age-
, if able) must be willing and able to use an 
eDiary device as required by the study.
Test Product, Dose and Mode of Administration:
A4250, 40 or 120 µg/kg/day orally administered.
Reference Therapy, Dose and Duration of Administration:
Not applicable.
Duration of Treatment:
72 weeks
Variables:
Efficacy:
Primary Efficacy Endpoints
European Union (EU) and rest of world: Change from baseline in serum bile acids after 72 weeks of 
treatment.
r

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Confidential
Amendment 6.2 Sweden, 11 February 2022
7
Name of Sponsor/Company:
Albireo AB
Name of Product:
A4250
Name of Active Ingredient:
A4250
US: Proportion of positive pruritus assessments at the patient level over the 72-week treatment period using 
the Albireo observer-reported outcome (ObsRO) instrument.
Secondary Efficacy Endpoints
EU and rest of world: Proportion of positive pruritus assessments at the patient level over the 72-week 
treatment period using the Albireo ObsRO instrument.
US: Change from baseline in serum bile acids after 72 weeks of treatment.
All Regions:
Change from baseline in serum bile acids at Weeks 4, 12, 22, 24, 36, 46, 48, 60, 70, 72, and 76
Proportion of individual assessments meeting the definition of a positive pruritus assessment at the 
patient level using the Albireo ObsRO instrument from Weeks 0-4, Weeks 0-12, Weeks 0-22, 
Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, Weeks 0-60, and Weeks 0-70, respectively, or 
the proportion of positive pruritus assessments at each 4-week interval between Visit 1/Screening 
and Visit 5/Week 24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76
Proportion of individual AM assessments meeting the definition of a positive pruritus assessment at 
the patient level using the Albireo ObsRO instrument from Weeks 0-4, Weeks 0-12, Weeks 0-22, 
Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, Weeks 0-60, Weeks 0-70, and Weeks 0-72, 
respectively, or the proportion of positive pruritus assessments at each 4-week interval between 
Visit 1/Screening and Visit 5/Week 24, then by each visit between Visit 5/Week 24 to
Visit 12/Week 76
Proportion of individual PM assessments meeting the definition of a positive pruritus assessment at 
the patient level using the Albireo ObsRO instrument from Weeks 0-4, Weeks 0-12, Weeks 0-22, 
Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, Weeks 0-60, Weeks 0-70, and Weeks 0-72, 
respectively, or the proportion of positive pruritus assessments at each 4-week interval between 
Visit 1/Screening and Visit 5/Week 24, then by each visit between Visit 5/Week 24 to
Visit 12/Week 76
All-cause mortality, number of patients undergoing biliary diversion surgery or liver transplantation. 
These parameters will be evaluated separately and together at weeks 24, 48, and 72
Change in growth from baseline to Weeks 24, 48, and 72 after initiation of A4250 treatment, defined 
as the linear growth deficit (height/length for age, weight for age, mid-arm circumference and body 
mass index [BMI]) compared to a standard growth curve (Z-score, standard deviation [SD] from P50)
Change in aspartate aminotransferase (AST) to platelet ratio index (APRI) score and fibrosis-4 (Fib-4) 
score from baseline to Week 72
Change in pediatric end-stage liver disease (PELD)/model for end-stage liver disease (MELD) score 
from baseline to Week 72
Change in use of antipruritic medication at Weeks 24, 48, and 72
Exploratory Efficacy Endpoints
All Exploratory Endpoints will be evaluated at Weeks 24, 48, and 72 unless otherwise noted. Baseline is 
calculated prior to initiation of A4250 treatment. Exploratory endpoints include:
Change in serum alanine aminotransferase (ALT), gamma-glutamyl transferase, and total bilirubin 
concentration from baseline to Week 72
Proportion of individual assessments meeting the definition of a positive pruritus assessment at the 
patient level over the 72-week Treatment Period. A positive pruritus assessment includes an itch score
-point drop from baseline based on the Albireo patient-reported outcome (PRO) 
instrument;
years of age will complete the Albireo PRO instrument
Change from baseline over the 72-week treatment period in sleep parameters measured with the 
Albireo PRO and ObsRO instruments

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Confidential
Amendment 6.2 Sweden, 11 February 2022
8
Name of Sponsor/Company:
Albireo AB
Name of Product:
A4250
Name of Active Ingredient:
A4250
Change from baseline in international normalized ratio, albumin, liver enzymes, leukocytes, and 
platelets
Change from baseline
-hydroxy-4-cholesten-3-
one [p-C4])
Assessment of Global Symptom Relief at weeks 4, 12, 24, 48 and 72 as measured by patient, caregiver, 
and clinician global impression of change (PGIC) items
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then 
by each visit between Visit 5/Week 24 to Visit 12/Week 76 in patient-reported and observer-reported 
night time itching and scratching severity scores, respectively
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then 
by each visit between Visit 5/Week 24 to Visit 12/Week 76 in patient-reported and observer-reported 
morning time itching and scratching severity scores, respectively
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then 
by each visit between Visit 5/Week 24 to Visit 12/Week 76 in pooled pruritus score including 
observer-reported scratching for patients <8 years of age and patient-reported itch severity for patients
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then 
by each visit between Visit 5/Week 24 to Visit 12/Week 76 in additional patient-reported and 
observer-reported sleep parameters (e.g., tiredness, number of awakenings)
Change from baseline in Pediatric Quality of Life Inventory (PedsQL) questionnaire 
Change from baseline in stage of liver fibrosis as assessed by Fibroscan® (where available)
Change from baseline in stage of liver fibrosis as assessed by post-treatment biopsy (when available)
Safety:
Safety criteria are as follows:
Occurrence of treatment-emergent AEs including severity and relatedness to study drug at all visits
The incidence of treatment-emergent serious adverse events (SAEs), based upon information from 
patient reports, including the description, causality, and severity of an SAE
Trends evaluated for the following assessments: physical examinations, concomitant medications, 
vital signs, laboratory test results (including clinical chemistry, hematology, urinalysis, alfa- 
fetoprotein, and vitamins A, E, and 25-hydroxy vitamin D), and abdominal ultrasound
Statistical Methods:
Descriptive statistics will mainly be used in this open-label extension study.
Baseline 1 will be defined as the last value prior to treatment start in study A4250-005 for Cohort 1 patients.
Baseline 2 will be defined as the last value prior to treatment start in Study A4250-008 for all patients. 
Baseline 2 will be used in all analyses unless otherwise specified.
The full analysis set (FAS) will consist of all patients who received at least 1 dose of study drug in Study 
A4250-008. The full analysis set will be the primary analysis set for all analyses unless otherwise specified. 
Evaluation of Primary Efficacy Variables:
The proportion of positive pruritus assessments at the patient level over the 72-week treatment period will be 
summarized.
-point drop
from baseline on the Albireo ObsRO instrument. At each assessment, the AM score will be compared to the 
baseline AM average, and the PM score will be compared to the baseline PM average. Both AM and PM 
pruritus assessments will be included in the analysis of this endpoint. Baseline will be defined as the average 
score from 14 days prior to treatment start in A4250-008 for AM and PM, respectively.
The change from baseline over the treatment period in serum bile acids will be analyzed mainly by using 
descriptive statistics. Fasting serum bile acids baseline will be calculated as the average of the pre-dose value 
in Study A4250-008 (Visit 1) and the previous visit (Visit 8 in study A4250-005) for Cohort 1. Fasting
serum bile acids baseline will be calculated as the average of Visit S-2 and the pre-dose Visit 1 values in

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
9 
 
 
 
Name of Sponsor/Company: 
Albireo AB 
Name of Product: 
A4250 
Name of Active Ingredient: 
A4250 
Study A4250-008 for Cohort 2. The end value is the average of the values at Weeks 70 and 72 in study 
A4250-008. 
Descriptive statistics will be summarized for Cohort 1, Cohort 2 excluding BRIC, Cohort 2 BRIC, and 
combined Cohort 1 + Cohort 2 excluding BRIC. Within Cohort 1, the following subgroups will be 
presented: ‘A4250 40 µg/kg/day (-005) to 120 µg/kg/day (-008)’, ‘A4250 120 µg/kg/day (-005) to 120 
µg/kg/day (-008)’, ‘A4250 40 µg/kg/day (-005) and 120 µg/kg/day (-005) to 120 µg/kg/day (-008)’, and 
‘placebo (-005) to 120 µg/kg/day (-008)’. Within Cohort 2 excluding BRIC, 3 subgroups (‘40 µg/kg/day’, 
‘40 µg/kg/day to 120 µg/kg/day’, and ‘120 µg/kg/day’) will be presented. Cohort 1 Placebo to A4250 
120 µg/kg/day will also be combined with Cohort 2 excluding BRIC for presentations. Change over time 
will also be displayed using graphical presentations (e.g., a spaghetti plot which illustrates the change in both 
Study A4250-005 and Study A4250-008 by treatment group in Study A4250-005). 
Evaluation of Secondary and Exploratory Efficacy Variables: 
All secondary and exploratory variables will be analyzed descriptively for categorical and continuous data, as 
applicable. For continuous data, the change from baseline will be analyzed in addition to the actual visit values. 
For categorical data, shift tables or frequency and percentages of patients will be presented as appropriate. 
Change in growth (Z-score, SD from P50 standard growth curve) will be analyzed by using one-sample T-test 
or Wilcoxon signed-rank test as appropriate. Change in growth (height/length for age, weight for age, mid- 
arm circumference and BMI) will also be displayed using graphical presentations. 
A 95% confidence interval (CI) will be calculated for the proportion of patients with at least one event, i.e., 
bile diversion or liver transplantation or death. The upper boundary will be compared to the expected 
proportion of events, using the event probability estimated from the untreated reference population in an 
ongoing observational cohort study. 
Time to first event, i.e., time to surgical bile diversion or liver transplantation or death, will be explored by 
descriptive statistics and Kaplan-Meier curves, which also will be used to make a comparison to the untreated 
reference population. 
Evaluation of Safety Variables: 
Safety data will be analyzed using descriptive statistics and summaries overall of SAEs, AEs, vital signs, 
clinical laboratory tests (hematology, clinical chemistry and urinalysis) and concomitant medication. Analyses 
will be performed using the full analysis set. 
Sample Size Determination: 
There is no formal hypothesis testing in this open label-study. Sample size for Cohort 1 was determined in 
Study A4250-005. For Cohort 1, patients will be enrolled following completion or participation of at least 12 
weeks of Study A4250-005. The expected proportion of patients with at least one event, i.e., surgical bile 
diversion or liver transplantation or death, in untreated patients is expected to be high enough to be able to 
detect an improvement after A4250 treatment. If the expected proportion with at least one event is estimated 
to be 30% in the study population of Cohort 1, and then if the proportion of patients with at least one event 
during A4250 long-term treatment are shown to be only 10% in the study, the power is approximately 89% to 
96% (1-sided test, alpha=2.5%) for a CI with upper boundary <30% based on a sample size of n=48 to 60. The 
sample size of 60 patients for Cohort 2 was estimated based on the availability of target patient population to 
evaluate the therapeutic benefit for those patients. 
Date of the Protocol: 11 February 2022 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
10 
 
 
 
3 
TABLE OF CONTENTS 
1 
ADMINISTRATIVE INFORMATION ................................................................... 4 
2 
STUDY SYNOPSIS ................................................................................................. 5 
3 
TABLE OF CONTENTS ....................................................................................... 10 
3.1 
List of Tables ............................................................................................ 14 
3.2 
List of Figures ........................................................................................... 14 
3.3 
List of Appendices and Supplements ........................................................ 14 
4 
LIST OF ABBREVIATIONS AND DEFINITION OF TERMS .......................... 15 
5 
INTRODUCTION .................................................................................................. 18 
5.1 
Investigational Medicinal Product ............................................................ 18 
5.2 
Background ............................................................................................... 18 
5.2.1 
Progressive Familial Intrahepatic Cholestasis ...................................... 18 
5.2.2 
Summary of Clinical and Nonclinical Studies ..................................... 20 
5.3 
Rationale .................................................................................................... 22 
5.3.1 
Risk/Benefit ........................................................................................... 23 
5.3.2 
Risk/Benefit  of  Receiving  COVID-19  Vaccine  during  Trial 
Participation ........................................................................................... 24 
6 
STUDY OBJECTIVES .......................................................................................... 26 
6.1 
Primary Objectives .................................................................................... 26 
6.2 
Secondary Objectives ................................................................................ 26 
7 
INVESTIGATIONAL PLAN ................................................................................ 27 
7.1 
Overall Study Design and Plan. ................................................................ 27 
7.1.1 
Description ............................................................................................. 27 
7.1.2 
Schedule of Assessments ....................................................................... 31 
7.1.3 
Study Procedures and Assessments ...................................................... 37 
7.1.3.1 
Screening Period (Days -56 to 0) (For Cohort 2 only) ......... 37 
7.1.3.2 
Treatment Period ................................................................... 38 
7.1.3.3 
End of Treatment/Early Termination .................................... 43 
7.1.3.4 
Follow-up Visit ..................................................................... 43 
7.2 
Study Population ....................................................................................... 44 
7.2.1 
Inclusion Criteria ................................................................................... 44 
7.2.2 
Exclusion Criteria .................................................................................. 45 
7.2.3 
Withdrawal of Patients .......................................................................... 47 
7.2.4 
Study Termination by Sponsor ............................................................. 48 
8 
TREATMENT OF PATIENTS .............................................................................. 49 
8.1 
Identity of Study Drug .............................................................................. 49 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
11 
 
 
8.2 
Administration of Study Drug .................................................................. 49 
8.3 
Study Drug Packaging and Labelling ....................................................... 52 
8.3.1 
Packaging and Labelling ....................................................................... 52 
8.3.2 
Storage ................................................................................................... 52 
8.3.3 
Blinding and Randomization of Study Drug ........................................ 52 
8.4 
Procedure for Breaking the Randomization Code .................................... 52 
8.5 
Patient Compliance ................................................................................... 52 
8.6 
Patient Identification ................................................................................. 53 
8.7 
Study Drug Accountability ....................................................................... 53 
8.8 
Concomitant Therapy and Prohibited Medications .................................. 53 
9 
ASSESSMENT OF EFFICACY ............................................................................ 54 
9.1 
Efficacy Endpoints .................................................................................... 54 
9.1.1 
Primary Efficacy Endpoints .................................................................. 54 
9.1.2 
Secondary Efficacy Endpoints .............................................................. 54 
9.1.3 
Exploratory Efficacy Endpoints ............................................................ 55 
9.2 
Efficacy Assessments ................................................................................ 56 
9.2.1 
Serum Bile Acids .................................................................................. 56 
9.2.2 
Itching and Sleep Score ......................................................................... 56 
9.2.3 
Growth ................................................................................................... 57 
9.2.4 
Biomarker Samples ............................................................................... 57 
9.2.5 
Change of Antipruritic Medication ....................................................... 57 
9.2.6 
Quality of Life Questionnaire (PedsQL) ............................................... 57 
9.2.7 
PELD/MELD Score .............................................................................. 57 
9.2.8 
Fibroscan® ............................................................................................................................................. 58 
9.2.9 
Markers of Fibrosis ............................................................................... 58 
9.2.10 
Liver Biopsy .......................................................................................... 58 
9.2.11 
Global Impression of Change and Global Impression of Symptom 
Measures ................................................................................................ 58 
10 
ASSESSMENT OF SAFETY ................................................................................ 59 
10.1 
Adverse Events ......................................................................................... 59 
10.1.1 
Definitions and Investigator Assessments ............................................ 59 
10.1.1.1 Clinical Significance .............................................................. 59 
10.1.1.2 Serious Adverse Events ......................................................... 59 
10.1.1.3 Severity Assessment .............................................................. 60 
10.1.1.4 Causality Assessment ............................................................ 60 
10.1.2 
Recording of Adverse Events ............................................................... 61 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
12 
 
 
10.1.3 
Recording and Reporting of Serious Adverse Events .......................... 62 
10.1.4 
Reporting of Suspected Unexpected Serious Adverse Reactions ........ 63 
10.2 
Laboratory Values/Vital Signs/Physical Examinations and Other Safety 
Assessments ............................................................................................... 64 
10.2.1 
Laboratory Assessments ........................................................................ 64 
10.2.2 
Individual Patient Safety Monitoring .................................................... 65 
10.2.2.1 Liver Monitoring ................................................................... 65 
10.2.2.2 Close Observation .................................................................. 66 
10.2.2.3 De-challenge/Re-challenge for Liver and Clinical Hepatitis 
Monitoring ............................................................................. 67 
10.2.2.4 Diarrhea ................................................................................. 67 
10.2.2.5 Fat-soluble Vitamin Deficiency ............................................ 68 
10.2.2.6 Treatment-emergent Iron Deficiency Anemia ...................... 68 
10.2.2.7 Re-challenge after Discontinuation/Interruption of Study 
Drug ....................................................................................... 68 
10.2.2.8 Monitoring after Permanent Discontinuation of Study Drug 
Due to Safety ......................................................................... 69 
10.2.3 
Demographics/Medical and Surgical History (For Cohort 2 only) ...... 69 
10.2.4 
Clinical Genetic Testing (For Cohort 2 only) ....................................... 69 
10.2.5 
Physical Examination ............................................................................ 69 
10.2.6 
Vital Signs ............................................................................................. 70 
10.2.7 
Abdominal ultrasound ........................................................................... 70 
10.2.8 
Overdose ................................................................................................ 70 
10.2.9 
Pregnancy .............................................................................................. 70 
11 
STATISTICAL EVALUATION ............................................................................ 72 
11.1 
Sample Size and Power ............................................................................ 72 
11.2 
Statistical Methods .................................................................................... 72 
11.2.1 
Statistical Analysis Sets ........................................................................ 72 
11.2.2 
Methods of Statistical Analyses ............................................................ 72 
11.2.2.1 General Principles .................................................................. 72 
11.2.2.2 Missing Data .......................................................................... 73 
11.2.2.3 Demographic and Baseline Characteristics ........................... 73 
11.2.2.4 Subject Disposition ................................................................ 73 
11.2.2.5 Evaluation of Primary Efficacy Variables ............................ 74 
11.2.2.6 Evaluation of Secondary and Exploratory Efficacy Variables 
. ............................................................................................ 74 
11.2.2.7 Evaluation of Safety Variables .............................................. 75 

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11.2.2.8 Compliance and Exposure ..................................................... 75 
11.2.3 
Interim Analysis .................................................................................... 76 
11.2.4 
Data Safety Monitoring Board .............................................................. 76 
12 
DIRECT ACCESS TO SOURCE DATA/NOTES ................................................. 77 
13 
QUALITY CONTROL AND QUALITY ASSURANCE ...................................... 78 
13.1 
Conduct of the Study ................................................................................. 78 
13.2 
Study Monitoring ....................................................................................... 78 
14 
ETHICS ................................................................................................................... 80 
14.1 
Independent Ethics Committee/Institutional Review Board ..................... 80 
14.2 
Written Informed Consents and Assents ................................................... 80 
15 
DATA HANDLING AND RECORD KEEPING .................................................. 82 
15.1 
Case Report Forms/Source Data Handling. ............................................... 82 
15.2 
Retention of Essential Documents ............................................................. 82 
16 
FINANCING AND INSURANCE .......................................................................... 83 
17 
PUBLICATION POLICY ....................................................................................... 84 
18 
REFERENCE LIST ................................................................................................. 85 
19 
APPENDICES ......................................................................................................... 87 

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3.1 
List of Tables 
Table 1 
Schedule of Assessments .............................................................................. 32 
Table 2 
Dosing and Capsule Strength ........................................................................ 51 
Table 3 
Routine Laboratory Parameters .................................................................... 65 
 
 
3.2 
List of Figures 
Figure 1 
Study Design up to Protocol Amendment 5.2 Sweden ................................ 30 
Figure 2 
Study Design for Cohort 2 as of Protocol Amendment 6.2 Sweden ........... 30 
 
 
3.3 
List of Appendices and Supplements 
Appendix 1 
Concomitant Medication Guidelines ............................................................ 87 
Appendix 2 
Diary Questions including Albireo Patient-Reported 
Outcomes/Observer-Reported Outcome Instrument .................................... 89 
Appendix 3 
Patient Global Impression of Change (PGIC) and Patient Global Impression 
of Symptoms (PGIS) ..................................................................................... 92 
Appendix 4 
Pediatric Quality of Life Inventory (PedQL) Questionnaire ........................ 97 
Appendix 5 
Guideline for Fat-Soluble Vitamin Supplementation ................................. 118 
Appendix 6 
Contraceptive Requirements ....................................................................... 121 
Appendix 7 
Blood Volumes ........................................................................................... 124 

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4 
LIST OF ABBREVIATIONS AND DEFINITION OF TERMS 
A4250 
odevixibat (non-proprietary name); Bylvay (brand name) 
ADME 
absorption, distribution, metabolism, and excretion 
AE(s) 
adverse event(s) 
AFP 
alfa-fetoprotein 
ALT 
alanine aminotransferase 
APRI 
AST to platelet ratio index 
ASBT 
apical sodium-dependent bile transporter (also known as IBAT) 
AST 
aspartate aminotransferase 
ATC 
Anatomical Therapeutic Chemical 
BMI 
body mass index 
BRIC 
benign recurrent intrahepatic cholestasis 
BSEP 
bile salt export pump 
CI 
confidence interval 
COVID-19 
coronavirus disease 2019 
CPK 
creatine phosphokinase 
CRA 
clinical research associate 
CYP 
cytochrome P450 
DDI 
drug-drug interaction 
DILI 
drug-induced liver injury 
DSMB 
Data and Safety Monitoring Board 
eCRF 
electronic case report form 
eDiary 
electronic diary 
EMA 
European Medicines Agency 
EOT 
End of Treatment 
EU 
European Union 
EudraCT 
 European Union drug regulatory agency clinical trial 
FAS 
full analysis set 
FDA 
(United States) Food and Drug Administration 
Fib-4 
fibrosis-4 
FIC1 
familial intrahepatic cholestasis-1 
FXR 
farnesoid X receptor 
GCP 
Good Clinical Practice 
GGT 
gamma-glutamyl transferase 
GI 
gastrointestinal 
IB 
Investigator’s Brochure 

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IBAT
ileal bile acid transporter (also known as ASBT)
ICF
informed consent form
ICH
International Council for Harmonisation
IEC
Independent Ethics Committee
INR
international normalized ratio
IRB
Institutional Review Board
iRIS
ICON Results Integration Services
IWRS
Interactive Web Response System
LDH
lactate dehydrogenase
LFT
liver function test
LPLV
last patient last visit
MDR3
multidrug-resistance protein 3 
MedDRA
Medical Dictionary for Regulatory Activities
MELD
model for end-stage liver disease
NAPPED
Natural Course and Prognosis of PFIC and Effect of Biliary 
Diversion
ObsRO
observer-reported outcome
PBC
primary biliary cholangitis
p-C4
 
-hydroxy-4-cholesten-3-one 
PCS
potentially clinically significant
PEDFIC 1 
Study A4250-005
PEDFIC 2 
Study A4250-008
PedsQL
Pediatric Quality of Life Inventory
PELD
pediatric end-stage liver disease
PFIC
progressive familial intrahepatic cholestasis
PGIC
patient global impression of change
PGIS
patient global impression of symptoms
P-gp
P-glycoprotein
PK
pharmacokinetic
PRO
patient-reported outcome
PT
prothrombin time
PVM
pharmacovigilance manager
QD
once daily
QoL
quality of life
SAE(s)
serious adverse event(s)
SAP
statistical analysis plan

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s-FGF19 
serum fibroblast growth factor 19 
SD 
standard deviation 
SOC 
system organ class 
SUSAR 
suspected unexpected serious adverse reaction 
TEAE(s) 
treatment-emergent adverse event(s) 
TJP2 
tight junction protein 2 
ULN 
upper limit of normal 
US 
United States 
WHO 
World Health Organization 

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5
INTRODUCTION
5.1
Investigational Medicinal Product
A4250 is a small molecule and a potent selective inhibitor of the ileal bile acid transporter 
(IBAT), also known as the apical sodium-dependent bile acid transporter (ASBT). IBAT is an 
integral brush border membrane glycoprotein that co-transports sodium and bile acids and 
appears to be a critical component in the regulation of the bile acid pool size in animals and 
man. This transporter, expressed in the distal ileum, is a key element in the enterohepatic 
circulation of bile acids since it facilitates the high-affinity, high-capacity reabsorption of bile 
acids.
Indeed, 95% of secreted bile acids are reabsorbed via IBAT [Hofmann 2009;
Miethke 2016]. A4250 is orally administered and acts locally in the gut where it binds 
reversibly to IBAT to decrease the reuptake of bile acids. A4250 has minimal systemic 
exposure at the predicted therapeutic dose ranges.
5.2
Background
5.2.1
Progressive Familial Intrahepatic Cholestasis
PFIC is a rare autosomal recessive cholestatic liver disease estimated to affect between one in 
every 50,000 to 100,000 children born worldwide. PFIC represents 10% to 15% of causes of 
cholestasis in children and 10% to 15% of liver transplantation indications in children. All 
types of PFIC exist worldwide and both sexes appear to be equally affected. 
The common underlying pathogenesis of PFIC is disruption of bile formation and bile transport 
through the liver [Jacquemin 2000]. The classification of PFIC has evolved over the years. 
The most commonly used subclassification is PFIC Types 1 to 6 which is based on the 
associated affected gene and described in more detail below.
PFIC, Type 1: also referred to as “Byler disease” or “familial intrahepatic cholestasis 1 
(FIC1) protein deficiency.” FIC1 protein is located on the canalicular membrane of 
hepatocytes and facilitates movement of aminophospholipids from the outer to inner leaflet 
of the plasma membrane of the hepatocyte. The ATP8B1 gene encodes FIC1 protein. 
Biallelic pathologic variants in the ATP8B1 gene are associated with FIC1 dysfunction and 
classified clinically as PFIC Type 1 disease.
PFIC, Type 2: also referred to as “Byler syndrome” or “bile salt export pump (BSEP) 
deficiency.” BSEP is a transporter protein that is expressed at the canalicular membrane 
of hepatocytes and is the primary exporter of bile acids. The ABCB11 gene encodes the 
BSEP protein. Biallelic pathologic variations in the ABCB11 gene is associated with BSEP 
dysfunction and is classified clinically as PFIC Type 2 disease.
PFIC, Type 3: is caused by a deficiency of the multidrug-resistance protein 3 (MDR3) due 
to mutations in the ABCB4 gene. MDR3 is a phospholipid translocase critical for 
phospholipid secretion.

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PFIC, Type 4 (tight junction protein 2 [TJP2] deficiency): is caused by biallelic mutations
in the TJP2 gene which encodes the tight junction protein 2 (TJP2) which is also called
zona occludens-2 [Bull 2018]. TJP2 is a cytoplasmic protein of cell-cell junctional 
complexes. While not part of the tight junction itself, tight junction proteins are closely 
associated with proteins that do form tight junctions, such as the claudins. 
PFIC, Type 5 (farnesoid X receptor [FXR] deficiency): Loss of function mutations in the 
NR1H4 gene encoding the farnesoid X receptor (FXR) result in PFIC5 [Sticova 2018]. FXR 
is a nuclear receptor activated by bile acids and is directly involved in the expression of
both BSEP and MDR3, proteins affected in PFIC2 and PFIC3, respectively [Gomez-Ospina
2016]. 
PFIC, Type 6 (MYO5B deficiency): PFIC6 results from defects in the Myo5B gene that 
codes for the actin-associated molecular motor known as MYO5B, which is essential for
the polarisation of hepatocytes as well as localising BSEP to the canalicular membrane 
[Vitale 2019]. 
Severe pruritus is common in children diagnosed with PFIC. Itching (and subsequent 
scratching) is a significant morbidity for these patients and their families [Suchy 2007]. A 
more severe degree of pruritus is experienced compared to patients with other forms of liver 
disease and to other pruritic conditions such as atopic dermatitis [Murray 2011]. In patients 
with PFIC, liver biopsy reveals canalicular cholestasis and, later, the appearance of portal 
fibrosis. Serum biochemistry indicates cholestasis with hyperbilirubinemia, elevated alanine 
aminotransferase (ALT) and aspartate aminotransferase (AST). The concentrations of bile
acids in serum are very high, while serum gamma-glutamyl transferase (GGT) activity (the 
exception being MDR3 variants) and cholesterol [Hori 2010] are normal. Symptoms of portal 
hypertension and liver failure will develop during the course of the disease [Davit-Spraul 2009; 
Alissa 2008]. Symptoms develop early; median age at onset of symptoms is 2 months, and
78% of PFIC patients present with jaundice [Pawlikowska 2010]. The life-threatening and 
debilitating nature of PFIC is reflected by the fact that survival in those not resorting to surgery 
is 50% at 10 years of age and almost zero at 20 years of age. Approximately half of PFIC 
patients undergo liver transplantation [Davit-Spraul 2009] and treatment resistant pruritus is 
the leading indication for the surgical procedure partial external biliary diversion, mostly in 
PFIC Type 1 and 2 patients. 
PFIC is life-threatening and debilitating. Other than odevixibat (A4250 non-proprietary name), 
which is approved for the treatment of PFIC by the European Medicines Agency (EMA) and
for the treatment of pruritus in patients with PFIC by the United States Food and Drug 
Administration (US FDA), the therapeutic choices are restricted to non-specific therapy of the 
symptoms and signs of the disease such as nutritional support, preventing vitamin deficiencies, 
and treatment of extrahepatic features. Medical treatment options include off-label use of 
ursodeoxycholic acid, rifampin, antihistamines, and naltrexone. A minority of patients respond 
nominally and transiently to these interventions. Biliary diversion is used to decrease systemic 

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bile acids through interruption of the enterohepatic circulation and so avoid transplantation. 
Liver transplantation is typically only viewed as an option when patients have failed medical 
treatment and/or biliary diversion and have liver failure or persistent uncontrolled pruritus. 
Previously, the term benign recurrent intrahepatic cholestasis (BRIC) was used to identify a 
group of patients with episodic cholestasis including severe pruritus and jaundice. Genetic 
analysis of patients with episodic cholestasis have identified mutations in the ATP8B1 and 
ABCB11 genes (the same mutations as PFIC1 and PFIC2). It is now generally recognised that, 
within each subtype, PFIC and BRIC represent 2 extremes of a continuous spectrum of 
phenotypes of the one disease [Bull 2018; Stapelbroek 2010; Sticova 2018]. 
Genetic diagnosis of BRIC Type 1 or BRIC Type 2 is based on evidence of mutations in both 
alleles of the corresponding genes. While the age of first manifestation can vary widely, BRIC 
usually manifests before the second decade of life. There is great variability in terms of 
frequency (months to years), duration (several days to several months), and intensity of 
cholestatic episodes. Clinical symptoms may include pruritus, jaundice, fatigue, anorexia, and 
steatorrhea [Strubbe 2012; Sticova 2018]. 
During cholestatic episodes, serum bile acids and bilirubin are typically increased, while GGT 
and serum cholesterol levels are normal [Sticova 2018]. Aminotransferases may be slightly 
elevated. Liver biopsies have shown hepatocanalicular cholestasis without fibrosis during 
cholestatic episodes and normal histology during the asymptomatic period. 
Therapeutic options for BRIC have not been very effective, including statins, corticosteroids, 
cholestyramine, or ursodeoxycholic acid [Sticova 2018]. While improvement in pruritus and 
decreased duration of symptomatic episodes have been reported with rifampicin, severe 
hepatotoxicity after long-term administration has been reported in patients with cholestatic 
disorders. 
5.2.2 
Summary of Clinical and Nonclinical Studies 
This is a summary of nonclinical and clinical studies. More detail is provided in the 
Investigator Brochure ([IB] see A4250 IB). 
A4250 is a potent selective IBAT inhibitor with no safety signals seen in the safety 
pharmacological studies. In addition, no safety signals were seen in repeat-dose oral toxicity 
studies in rats with up to 26 weeks of daily dosing and in dogs with up to 39 weeks of daily 
dosing. A4250 showed no carcinogenic potential in 2-year carcinogenicity studies conducted 
in mice and rats. No safety signals were identified when A4250 was administered daily to 
juvenile rats from age 14 days to 63 days. Based on findings from animal reproduction studies, 
A4250 may cause cardiac malformations when a fetus is exposed during pregnancy. In 
pregnant rabbits treated orally with A4250 during organogenesis, an increased incidence of 
malformations in fetal heart, great blood vessels, and other vascular sites occurred at all doses; 
maternal systemic exposure at the lowest dose was 2.1 times the maximum recommended dose. 
No such malformations were observed when A4250 was administered to pregnant rats. A4250 

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had no effect on the reproductive performance, fertility, embryo-foetal development, or 
prenatal/postnatal development studies in rats.
A4250 is minimally absorbed with very low systemic exposure in both humans and other 
species. In blood, protein binding is high (>99.7%). Systemically absorbed A4250 is slowly 
metabolized in humans and in preclinical studies by hydroxylation only, a metabolite that
retains IBAT activity.  A4250 did not show any significant inhibition of cytochrome 
P450 (CYP)
enzymes
in
the
rat.
A4250
inhibited
human
CYP3A4
and
CYP2D6 
(IC50: 16 µmol/L for both enzymes), and CYP2C9 (IC50: 1.2 µmol/L).
To date, A4250 has been studied in 6 completed Albireo-sponsored clinical studies: a study in 
healthy volunteers evaluating single and multiple administration of A4250; a single-dose 
absorption, distribution, metabolism, and excretion (ADME) study; a single-dose food 
interaction study in healthy subjects; a drug-drug interaction (DDI) study in healthy subjects; 
a Phase 2 study in children with cholestatic pruritus; and a Phase 3 study in children with PFIC. 
In addition, an investigator-sponsored study has been conducted in patients with primary biliary 
cholangitis (PBC). In total, 258 subjects/patients have been exposed to A4250 in completed
and ongoing studies.
In healthy volunteers (study A4250-001), dosing with A4250 at single doses of 0.1-10.0 mg
and multiple doses from 1-3 mg daily for up to 7 days induced anticipated changes in bile acid 
synthesis biomarkers (i.e., decreased serum fibroblast growth factor 19 [s-FGF19] and
increased 
hydroxy 4-cholesten-3-one [p-C4]). In addition, total plasma bile acids 
decreased and total fecal bile acids increased compared to placebo treatment.
The clinical development program has generated data demonstrating minimal systemic total 
exposure in the low nanomolar range with very high protein binding and no detectable levels 
of metabolites. An ADME study (A4250-007) demonstrated that A4250 is excreted unchanged 
primarily in the feces. A population pharmacokinetic (PK) analysis confirmed that A4250 
presented very low systemic exposure in pediatric patients with PFIC with rapid elimination.
No accumulation of A4250 is expected following repeated administration of therapeutic doses 
(40 and 120 µg/kg/day). No dose adjustment is required in subpopulations.
In a food interaction study (A4250-004) following administration of a single oral dose of
9.6 mg A4250, plasma concentrations and systemic exposure to A4250 were low, regardless 
of feeding status, indicating minimal absorption through the gastrointestinal (GI) tract. In a
DDI study (A4250-013), no clinically relevant drug-drug interactions with A4250 and a 
CYP3A4 substrate or a P-glycoprotein (P-gp) inhibitor were identified, although A4250 was a 
P-gp substrate. 
In a study with 4-week, once-daily oral treatment with A4250 in children with cholestatic liver 
disease and pruritus, A4250 reduced mean levels of serum bile acids in all treatment groups 
(5 dose groups ranging from 10-200 µg/kg/day [0.01-0.20 mg/kg/day]) (Study A4250-003). 
Patient-reported diaries documented improvement of the visual analogue scale (VAS)-itch

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score (Scale 0-10) in 17 of 24 patients during treatment, with the greatest improvement at a 
dose of 100 µg/kg/day. 
In a Phase 3 randomized double-blind study in children with PFIC, treatment with A4250 at 
doses of 40 and 120 µg/kg/day led to statistically significant reductions in serum bile acid levels 
and pruritus symptoms over 24 weeks compared with placebo (study A4250-005; PEDFIC 1). 
These improvements occurred rapidly and were sustained during continued treatment. Results 
for secondary and exploratory endpoints were generally consistent with the reductions in serum 
bile acids and pruritus showing improvements in sleep, hepatic biochemical parameters and 
hepatic health, and quality of life (QoL) measures. 
A4250 has been generally well tolerated in all completed studies. Adverse events (AEs) 
reported have primarily been of mild to moderate intensity. In total, 6 serious adverse events 
(SAEs) have been reported; none judged by the investigator to be causally related to the study 
drug. No deaths related to the drug have been reported. Abdominal pain and diarrhea have 
been the most prominent AEs in adults, while diarrhea, pyrexia, and upper respiratory tract 
infection have been the most commonly reported AEs in children. The most commonly 
reported study drug-related AEs in children were increases in alanine aminotransferase (ALT), 
aspartate aminotransferase (AST), and blood bilirubin. 
5.3 
Rationale 
The investigational product A4250 (non-proprietary name odevixibat; brand name Bylvay) has 
been approved for the treatment of PFIC by the EMA and for the treatment of pruritus in 
patients with PFIC by the US FDA. A4250 is also currently being developed for other orphan 
cholestatic liver diseases. 
In PFIC patients with severe pruritus, biliary diversion surgery is used to decrease systemic 
bile acids through interruption of the enterohepatic circulation and thereby reduce pruritus 
[Whitington 1988]. Liver transplantation is typically used as an option when patients have 
failed medical treatment and/or biliary diversion and have liver failure or persistent 
uncontrolled pruritus. 
By inhibiting IBAT with high selectivity and potency, A4250 has the potential to relieve 
cholestasis and improve liver function without surgical intervention in patients with PFIC. 
Since A4250 is minimally absorbed and achieves a substantial reduction of serum bile acids, it 
has the potential to be a safer and less invasive alternative to surgical biliary drainage. The 
rationale for using A4250 is to decrease serum bile acid levels, and to reduce the major 
morbidity of pruritus, improving the health and wellbeing of patients affected with PFIC. 
Ultimately, this noninvasive therapeutic approach has the potential to not only improve QoL, 
but also reduce the need for biliary diversion and subsequent liver failure and liver 
transplantation. 
The doses selected for the A4250-005 Phase 3 study, 40 and 120 µg/kg/day, were based on the 
efficacy and safety data generated from patients with PFIC (n=10 + 3 re-entered) and 

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supporting data from all patients (n=20 + 4 re-entered) in the five dose groups dosed in the 
A4250-003 Phase 2 study. Improvements of serum bile acids and pruritus were observed with 
doses from 30 to 100 µg/kg/day with a dose-related trend. The best dose response in all patients 
was at the 60 µg/kg/day for serum bile acids and 100 µg/kg/day for pruritus. The best dose 
response in the PFIC subgroup was at 30 µg/kg/day for both serum bile acids and pruritus. 
Patients with PFIC responded well to the doses given from 30 to 200 µg/kg/day; however, a 
clear dose relationship could not be established in order to select a single dose for the A4250- 
005 study. As efficacy was observed at both low and high doses, 40 and 120 µg/kg/day were 
considered to be the most optimal for the A4250-005 study. Both low and high doses, 
40 µg/kg/day 2 and 120 µg/kg/day, will be used in this study.  Patients not tolerating the 
120 µg/kg/day dose may down-titrate to the lower dose after a minimum of 1 week on the high 
dose. The patient should return to the higher dose as soon as deemed appropriate by the 
investigator. More than one upward dose titration (from 40 µg/kg/day directly to 120 
µg/kg/day) for the same event is not recommended. Any dose titration should be done in 
consultation with the sponsor Medical Monitor or designee. 
Rationale for patient selection: 
Cohort 1: Patients in Cohort 1 are children with PFIC Types 1 and 2 who have completed study 
A4250-005 (PEDFIC 1) and will be enrolled to collect data on the efficacy (impact on pruritus 
and clinical laboratory parameters) and safety of long-term administration of A4250. 
Cohort 2: Cohort 2 will enroll patients with PFIC who (1) were not eligible to enroll in 
A4250-005 (PEDFIC 1) or (2) are eligible for enrolment in A4250-005 after recruitment of 
study A4250-005 has been completed. As these patients will have cholestatic liver disease 
with elevated serum bile acids and pruritus, reduction of serum bile acids with A4250 treatment 
is believed to provide a therapeutic benefit for these patients. These patients will be enrolled 
to collect data on the efficacy (impact on pruritus and clinical laboratory parameters) and safety 
of long-term administration of A4250. 
This study will be conducted in compliance with the protocol and with the International 
Council for Harmonisation (ICH) guidelines on Good Clinical Practice (GCP). 
5.3.1 
Risk/Benefit 
Following review of the available safety and efficacy data, A4250 (INN odevixibat) has been 
approved by the EMA and the US FDA for use in patients with PFIC. A4250 has been 
evaluated in 6 Albireo-sponsored clinical studies: a double-blind placebo-controlled study in 
healthy volunteers, a single-dose ADME study, a single-dose food interaction study, a DDI 
 
 
 
2 As of Protocol Amendment 6.2 Sweden, patients entering Cohort 2 will start treatment at 40 µg/kg/day 
with the possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus 
based on investigator judgment. 

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study, a Phase 2 study in children with cholestatic pruritus, and a Phase 3 study in children with 
PFIC. In addition, an investigator sponsored study has been conducted in patients with PBC.
A total of 258 subjects/patients have been exposed to A4250. Healthy subjects have been 
exposed to up to 10 mg as a single dose and up to 3 mg daily as part of a multiple-dose 
evaluation. Children with cholestatic liver disease have been treated with up to 200 µg/kg/day 
for 4 weeks. In the Phase 3 study in children with PFIC, children have been treated with A4250 
for 24 weeks at a dose of 40 
Two SAEs were reported in the 
Phase 2 study and 4 SAEs were reported in 3 patients receiving A4250 in the Phase 3 study; 
all were judged by the investigator to be not related to the study drug.
Patients with cholestatic liver diseases suffer from excess bile acids in the liver resulting in 
tissue damage. A commonly used treatment in these patients is bile diversion surgery, whereby 
approximately 50% to 100% of the enterohepatic circulation of bile acids is interrupted. 
Inhibition of IBAT with A4250, thereby interrupting the enterohepatic circulation of bile acids, 
is therefore a potential medical alternative to surgery which could be of benefit to these patients 
if shown to be effective and safe. Data from the Phase 2 and 3 studies showed efficacy of 
A4250 in reducing serum bile acid concentrations and pruritus in such patients. 
Based on the mode of action of A4250, an IBAT inhibitor, loose stools or diarrhea, and 
abdominal pain are expected AEs. Non-serious diarrhea and abdominal pain were reported in 
healthy volunteers and in the investigator-initiated PBC study and in one patient following 
single dose, but none following multiple dosing in the Phase 2 study in pediatric patients with 
pruritic cholestatic liver disease. Non-serious diarrhea, vomiting, and abdominal pain were 
observed in the Phase 3 study in pediatric patients with PFIC. 
A4250 taken once daily (QD) at doses up to 200 µg/kg/day, as tested in the Phase 2 study 
A4250-003, and up to 120 µg/kg/day as evaluated in the Phase 3 study A4250-005, was overall 
well tolerated. Gastrointestinal (GI) treatment-emergent adverse events (TEAEs) including 
abdominal pain, abdominal discomfort and diarrhea or loose stool, were associated in time with 
the onset of the treatment effect of A4250. In general, these AEs were mild to moderate in 
nature and self-limiting, did not require treatment intervention and were not linked to the degree 
of reduction of serum bile acid or a rapid reduction in serum bile acid levels. 
5.3.2
Risk/Benefit of Receiving COVID-19 Vaccine during Trial Participation
Nonclinical: The risk of immunotoxicity has been evaluated based on results from standard 
toxicity studies. No obvious signs in related organs have been detected in response to A4250 
treatment (e.g., changes in thymus, spleen, lymph nodes, or bone marrow). Altered hematology 
and incidence of infection have not been detected. Neither IBAT specifically nor bile acids in 
general are expected to perturb immunological responses. No signs of immunological reactions 
have been seen in clinical trials thus far. Based on the outcome from the standard toxicity 
studies and the general profile and mechanism of action of A4250, the risk of immunotoxicity 
has been considered low and dedicated immunotoxicity studies have not been performed. 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
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Amendment 6.2 Sweden, 11 February 2022 
25 
 
 
 
Clinical: Based on an integrated safety analysis of data from the completed A4250-005 study 
and the ongoing open-label extension study A4250-008 in patients with PFIC treated for 48 
weeks or longer with A4250, no safety signal or trends relative to immunological reactions 
have been reported. This is consistent with the mechanism of action of A4250 and the non- 
clinical data. No trends or safety signals were observed as it relates to hematology including 
white blood cell count, differential counts and C-reactive protein. No events of allergic 
reactions to A4250 or its excipients have been reported. 
The overall incidence of infections was 49% (41 of 84 patients) with upper respiratory tract 
infection being the most common type of infection reported in 24% of patients. Other 
commonly reported infections were 
nasopharyngitis, 
otitis media, influenza, 
and 
gastroenteritis, reported in 11%, 7%, 6%, and 6%, respectively, of patients in the PFIC Phase 
3 studies. 
The risk of an undesirable outcome after receiving the COVID-19 vaccine while treated with 
A4250 has not been studied and is unknown. 

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Confidential
Amendment 6.2 Sweden, 11 February 2022
26
6
STUDY OBJECTIVES
6.1
Primary Objectives
Primary Objective (Cohort 1)
To demonstrate a sustained effect of A4250 on serum bile acids and pruritus in children with 
PFIC Types 1 and 2. 
Primary Objective (Cohort 2)
To evaluate the effect of A4250 on serum bile acids and pruritus in patients with PFIC who 
either (1) do not meet eligibility criteria for Study A4250-005 (PEDFIC 1) or (2) who do 
meet the eligibility criteria for Study A4250-005 after recruitment of Study A4250-005 has 
been completed. 
6.2
Secondary Objectives
Secondary Objectives (Cohorts 1 and 2)
The secondary objectives of this study are:
To evaluate the long-term safety and tolerability of repeated daily doses of A4250
 
To evaluate the effect of A4250 on growth 
To evaluate the effect of A4250 on biliary diversion and/or liver transplantation
To evaluate the effect of A4250 on biochemical markers of cholestasis and liver disease

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
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Amendment 6.2 Sweden, 11 February 2022
27
7
INVESTIGATIONAL PLAN
7.1
Overall Study Design and Plan
7.1.1
Description
This is a Phase 3, multi-center, open-label extension study to investigate the long-term efficacy 
and safety of a 120 µg/kg daily dose of A4250 in patients with PFIC, including episodic forms 
also referred to as BRIC. Cohort 1 will consist of children with PFIC Types 1 and 2 who have 
participated in Study A4250-005. Cohort 2 will consist of approximately 60 patients with any 
type of PFIC who have elevated serum bile acids and cholestatic pruritus and who either (1) do 
not meet eligibility criteria for Study A4250-005 (PEDFIC 1) or (2) are eligible for enrolment
in A4250-005 after recruitment of study A4250-005 has been completed. Up to 40 patients
post biliary diversion surgery are allowed to participate in Cohort 2. 
The study includes a 72-week Treatment Period and a 4-week Follow-up Period.Upon 
completion of the study, patients will be eligible to be offered continued treatment through 
compassionate use or name patient/license basis until the drug is commercially available, 
provided continued use is supported by the risk-benefit profile and the subject has not been 
previously withdrawn or discontinued from the study. The study data will be reviewed 
periodically (approximately on a quarterly basis) by a Data Safety and Monitoring Board 
(DSMB).
Eligible patients will be enrolled into this open-label extension study and treated with a daily 
dose of 40 µg/kg/day3 or 120 µg/kg/day of A4250 for 72 weeks, or 40 µg/kg/day for the first 
12 weeks followed by 120 µg/kg/day for the remaining 60 weeks3. Patients not tolerating the 
120 µg/kg/day dose after a minimum of 1 week for reasons other than new liver findings and 
severe diarrhea, as described in Section 10.2.2, will have the option to down-titrate to a lower 
dose (40 µg/kg/day). The patient should return to the higher dose as soon as deemed 
appropriate by the investigator. More than one upward dose titration (from 40 µg/kg/day
directly to 120 µg/kg/day) for the same event is not recommended. Any dose titration should 
be done in consultation with the sponsor Medical Monitor or designee.
Patients in Cohort 2 will go through a screening period consisting of:
Visit S-1: Screening Visit 1 (Days -56 to -35). 
Visit S-2: Screening Visit 2 (Days -28 to -7)
Patients not meeting eligibility criteria may be re-screened after consultation with the Medical 
Monitor. Patients not fulfilling inclusion/exclusion criteria after 3 attempts are not allowed to 
rescreen.
3 As of Protocol Amendment 6.2 Sweden, patients entering Cohort 2 will start treatment at 40 µg/kg/day 
with the possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus 
based on investigator judgment.

A4250 – IND 130591 
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Module 5: Clinical Study Reports 
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Amendment 6.2 Sweden, 11 February 2022
28
Patients will have a minimum of 12 visits at the study site and 6 scheduled telephone contacts 
(see Figure 1 and Figure 2) as follows:
Visit 1: Screening/Inclusion Visit (Day 1; coincides with Visit 9 in Study A4250-005 for 
patients in Cohort 1) 
Visit 2: Week 4 
Telephone contact 1: Week 8 
Visit 3: Week 12
Telephone contact 2: Week 18
Visit 4: Week 22
Visit 5: Week 24
Telephone contact 3: Week 30
Visit 6: Week 36
Telephone contact 4: Week 42
Visit 7: Week 46
Visit 8: Week 48
Telephone contact 5: Week 54
Visit 9: Week 60
Telephone contact 6: Week 66
Visit 10: Week 70
Visit 11: Week 72
Visit 12: Follow-up Visit; Week 76
Additional clinic visits may be required for patients who need direct site assistance including, 
but not limited to, AE monitoring for safety maintenance.
Informed consent must be obtained prior to performing any study procedures. After signing 
the informed consent form (ICF), patients will be evaluated for study eligibility and considered 
enrolled in the study. For Cohort 1, patients who completed 24 weeks, or who withdrew after 
a minimum of 12 weeks of treatment with A4250 due to intolerable symptoms in Study A4250- 
005 and meeting all inclusion criteria and no exclusion criteria are eligible for this study. 
Patients who withdraw from A4250-005 due to a study drug related AE will not be eligible. 
For Cohort 2, patients meeting all inclusion criteria and no exclusion criteria are eligible for
this study. 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
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Amendment 6.2 Sweden, 11 February 2022 
29 
 
 
 
Patients/caregivers will be instructed to fill in the electronic diary (eDiary) every morning and 
evening for the first 24 weeks (Visit 1 through Visit 5) and the 21 days before each clinic visit 
thereafter (Visit 6 through Visit 12). In addition, Cohort 2 patients/caregivers will be instructed 
to fill in the eDiary during the screening period. The eDiary will include patient-reported 
outcome (PRO) and observer-reported outcome (ObsRO) items for evaluation of itching 
(PRO), scratching (ObsRO), and sleep disturbance (PRO and ObsRO). Observer-reported 
outcomes in patients of all ages will be recorded by a caregiver. If possible, the same caregiver 
will complete the ObsRO items throughout the study. Additionally, caregivers will be 
requested to report in the diary the time that study drug was administered during the Treatment 
Period. 
The patient will return to the clinic after 4 weeks and 12 weeks and thereafter every 10 to 
12 weeks for follow-up measurements. Between the clinic visits there will be a telephone 
contact with the patient/caregiver to report AEs. 
The last dose of study drug is taken in the morning the day before Visit 11. If the patient is 
prematurely withdrawn from the study, all assessments scheduled for Visit 11 will be 
performed at the time the patient withdraws. 
If a liver biopsy is performed according to the local regulations or standard of care at any time 
during A4250-008, the biopsy results should be recorded in the electronic case report form 
(eCRF). If the patient had liver biopsy results collected in study A4250-005 or prior to Week 
24 in study A4250-008, the patient will be asked to consent to a follow-up liver biopsy, if 
allowed per local regulations, at Visit 11, unless 2 prior liver biopsy results have been collected 
with at least 1 year between biopsies. Liver biopsies will not be performed in Spain. 
Visit 12 will take place 28 days after Visit 11. All patients prematurely withdrawn will have 
this visit 28 days after the last dose of study drug for AE and other follow-up. 
If a patient discontinues prior to Week 72, additional telephone contacts will be made every 
3 months after the Follow-up Visit (Visit 12) up to Week 72 to gather whether or not the patient 
has had biliary diversion or liver transplantation, and if TEAEs ongoing at the time of 
discontinuation have resolved. The telephone calls will take place up until 72 weeks even if the 
patient has biliary diversion or liver transplant. 
Details of study assessments are provided in the schedule of assessments (Table 1). 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
30 
 
 
 
Figure 1    Study Design up to Protocol Amendment 5.2 Sweden 
 
QD: once daily; T: telephone contact; V: study visit; VS: Visit Screening 
Note: Visit 1 coincides with Visit 9 of Study A4250-005. Patients who are not tolerating the 120 µg/kg/day dose 
may be down-titrated to the 40 µg/kg/day dose following a minimum of 1 week of treatment. The patient can 
return to the higher dose as soon as deemed appropriate. 
This figure is only applicable to Cohort 2 up to Protocol Amendment 5.2 Sweden. Figure 2 presents the study 
design for Cohort 2 as of Protocol Amendment 6.2 Sweden. 
 
Figure 2    Study Design for Cohort 2 as of Protocol Amendment 6.2 Sweden 
 
 
QD: once daily; T: telephone contact; V: study visit; VS: Visit Screening 
Note: As of Protocol Amendment 6.2 Sweden, patients entering Cohort 2 will start treatment at 40 µg/kg/day with 
the possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus based on 
investigator judgment. The patient can return to the lower dose if the 120 µg/kg/day dose is not tolerated following 
a minimum of 1 week of treatment. 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
31 
 
 
 
End of Study 
The end of the study is defined as follows: 
a) End of study in one country: last patient last visit (LPLV) and sites are closed. 
b) End of study globally: LPLV globally and all sites closed 
7.1.2 
Schedule of Assessments 
The schedule of assessments is presented in Table 1. For information on blood volumes, please 
see Appendix 7. 

A4250-IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 - Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
32 
 
 
Table 1 
Schedule of Assessments 
 
 
Screening 
Period (Cohort 
2 only) 
Treatment Period 
Follow- 
up 
I 
Period 
Study Activity 
Screen!ng/ I 
4 
I 
12  I 
22  I 
24  I 
36  I 
46  I 
48  I 
60  I 
70  I 
72 
I 76 weeks 
IncVl iton 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
ISi 
Study Days 
-56- 
(±window) 
(-35) 
±2 
-28- 
(-7) 
±2 
1 
28 
84 
154 
168 
252 
322 
336 
420 
490 
504 (±7) 
I 532 (±7) 
(±5) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
I 
I 
I 
I 
I 
I 
Clinic Visits 
Visit 
S-1 
Visit 
S-2 
Visit 1• 
Visit 
2 
Visit 
3 
Visit 
4 
Visit 
5 
Visit 
6 
Visit 
7 
Visit 
8 
Visit 
9 
Visit 
10 
Visit 11/EOTb 
Visit 12c 
Informed consent 
X 
Xd 
Inclusion/exclusion 
criteria 
X 
X 
Demography/Medical 
and Surgical History 
X 
Concomitant 
medicatione 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Physical examinationr 
X 
X 
X 
X 
X 
X 
Skin examination 
X 
X 
X 
X 
X 
X 
X 
Vital signsg 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
eDiary: itching, 
scratching, and sleep 
scoresh 
Daily diary entry 
For 21 days before each clinic visit for Visit 6 through Visit 12 
Clinical chemistryi 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 

A4250-IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 - Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
33 
 
 
 
Screening 
Period (Cohort 
2 only) 
Treatment Period 
Follow- 
up 
Period 
Study Activity 
Screen!ng/ I 
4 
I 
12  I 
22  I 
24  I 
36  I 
46  I 
48  I 
60  I 
70  I 
72 
I 76 weeks 
IncVl iton 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
ISi 
-56- 
-28- 
1 
28 
84 
154 
168 
252 
322 
336 
420 
490 
504 (±7) 
I 532 (±7) 
(±5) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
I 
I 
I 
I 
I 
I 
Study Days 
(-35) 
(±window) 
±2 
(-7) 
±2 
Clinic Visits 
Visit 
S-1 
Visit 
S-2 
Visit I" 
Visit 
2 
Visit 
3 
Visit 
4 
Visit 
5 
Visit 
6 
Visit 
7 
Visit 
8 
Visit 
9 
Visit 
10 
Visit 11/EOTb 
Visit 12c 
Hematologyi 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Urinalysisi 
X 
X 
X 
X 
International 
normalized ratio 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Serum bile acid&i 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Autotaxink 
X 
X 
X 
X 
X 
p-C4k 
X 
X 
X 
X 
X 
Alfa-fetoprotein 
X 
X 
X 
X 
Vitamins Ai, E and 
25-hydroxy vitamin D 
X 
X 
X 
X 
X 
X 
X 
Abdominal ultrasound 
X 
X 
X 
X 
Fibroscan (where 
available) 
X 
X 
X 
X 
QoL questionnaire 
(PedsQL) 
X 
X 
X 
X 

A4250-IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 - Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
34 
 
 
 
Screening 
Period (Cohort 
2 only) 
Treatment Period 
Follow- 
up 
I 
Period 
Study Activity 
Screen!ng/ I 
4 
I 
12  I 
22  I 
24  I 
36  I 
46  I 
48  I 
60  I 
70  I 
72 
I  76 weeks 
IncVl iton 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
ISi 
-56- 
-28- 
1 
28 
84 
154 
168 
252 
322 
336 
420 
490 
504 (±7) 
I 532 (±7) 
(±5) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
I 
I 
I 
I 
I 
I 
Study Days 
(-35) 
(±window) 
±2 
(-7) 
±2 
Clinic Visits 
Visit 
S-1 
Visit 
S-2 
Visit I" 
Visit 
2 
Visit 
3 
Visit 
4 
Visit 
5 
Visit 
6 
Visit 
7 
Visit 
8 
Visit 
9 
Visit 
10 
Visit 11/EOTb 
Visit 12c 
Patient/Caregiver/Clin 
ician Patient Global 
Impression of Change 
X' 
X 
X 
X 
X 
X 
Patient/Caregiver/Clin 
ician Patient Global 
Impression of 
I 
I 
X 
I 
X 
I 
X 
X 
I 
I 
I 
X 
I 
X 
Symptoms 
Pregnancy test1 
xi 
X 
xi 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Telephone contact 
Patients will be contacted via telephone for adverse event monitoring at Weeks 8, 18, 30, 42, 54, and 66 
Liver biopsy"' 
X 
Study drug dispensed" 
X 
X 
X 
X 
X 
X 
X 
X' 
Adverse events0P 
Continuous collection 
Study drug 
compliance evaluated 
X 
xq 
X 
xq 
X 
X 
xq 
eCRF: electronic case report form; eDiary: electronic diary; EOT: end of treatment; p-C4: plasma 7a Hydroxy 4-cholesten-3-one; PedsQL: pediatric quality of life; QoL: 
quality of life. 

A4250-IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 - Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
35 
 
 
 
Screening 
I 
Treatment Period 
Period (Cohort 
2 only) 
Follow­ 
up 
Period 
Study Activity 
I 
Screen!ng/ I 
4 
I 
12  I 
22  I 
24  I 
36  I 
46  I 
48  I 
60  I 
70 
72 
weeks 
76 weeks 
IncVl iton 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
ISi 
-56- 
-28- 
1 
28 
84 
154 
168 
252 
322 
336 
420 
490 
(±5) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
I 
I 
I 
I 
I 
I 
504 (±7) 
532 (±7) 
Study Days 
(-35) 
(±window) 
±2 
(-7) 
±2 
Clinic Visits 
Visit 
S-1 
Visit 
S-2 
Visit I" 
Visit 
2 
Visit 
3 
Visit 
4 
Visit 
5 
Visit 
6 
Visit 
7 
Visit 
8 
Visit 
9 
Visit 
10 
Visit 11/EOTb 
Visit 12c 
a 
For patients in Cohort 1, Visit 1 coincides with Visit 9 in Study A4250-005. Assessments that have been performed at Visit 9 during Study A4250-005 will not be 
repeated. 
b 
Assessments must also be performed at the time a patient is prematurely withdrawn from the study. If a patient discontinues prior to week 72, additional phone contact 
will be made every 3 months up to a total study participation of 72 weeks to assess if the patient has had biliary diversion or liver transplantation. 
c 
Assessments must be performed 28 days following the final dose of study drug. 
d 
Only for Cohort 1. 
e 
Includes current medications. 
f 
A complete physical exam will be performed at Visits S-1, I, 3, 5, 8, and 11/EOT. 
g 
Includes blood pressure, pulse, respiratory rate, temperature, height/length (using a certified stadiometer), mid-arm circumference (3 repeat measures), and body weight 
(using a certified weight scale). Body mass index will be calculated. 
h 
Itching, scratching, and sleep will be assessed via an eDiary (issued with any necessary training to patients/caregivers at Visit 1). Patients/caregivers will be instructed 
to fill in the eDiary every morning and evening for the first 24 weeks and the last 21 days before all the remaining visits to the clinic. There will be no interruption 
between Visits 11 and 12. 
See Table 3 for detailed parameters. 
j 
Patients will fast (only water intake is permissible) for at least 4 hours prior to the collection of samples for serum bile acids and vitamin A. Exceptions can be made for 
infants, less than 12 months of age, if unable to fast for the entire 4 hours. 
k 
Autotaxin and p-C4 samples will not be collected for patients :S 10 kg. 
For girls who have reached menarche. Serum test will be performed at Visit S-1 for Cohort 2 only and Visit 1 (for Cohort 1 only); urine test will be performed at all 
other visits. If a urine pregnancy test is positive, a serum pregnancy test should be performed to confirm the pregnancy. 

A4250-IND 130591 
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Amendment 6.2 Sweden, l l February 2022 
36 
 
 
 
Screening 
I 
Treatment Period 
Period (Cohort 
2 only) 
Follow­ 
up 
Period 
Study Activity 
I 
Screen!ng/ I 
4 
I 
12  I 
22  I 
24  I 
36  I 
46  I 
48  I 
60  I 
70 
72 
weeks 
76 weeks 
IncVl iton 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
ISi 
-56- 
-28- 
1 
28 
84 
154 
168 
252 
322 
336 
420 
490 
(±5) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
I 
I 
I 
I 
I 
I 
504 (±7) 
532 (±7) 
Study Days 
(-35) 
(±window) 
±2 
(-7) 
±2 
Clinic Visits 
Visit 
S-1 
Visit 
S-2 
Visit I" 
Visit 
2 
Visit 
3 
Visit 
4 
Visit 
5 
Visit 
6 
Visit 
7 
Visit 
8 
Visit 
9 
Visit 
10 
Visit 11/EOTb 
Visit 12c 
m If a liver biopsy is performed at any time during A4250-008 according to the local regulations or standard of care, the biopsy results should be recorded in the eCRF. If 
the patient has liver biopsy results collected in study A4250-005 or prior to Week 24 in study A4250-008, the patient will be asked to consent to a follow up liver 
biopsy, if allowed per local regulations, at Visit 11 unless 2 prior liver biopsy results have been collected with at least l year between biopsies. Liver biopsies will not 
be performed in Spain. 
n 
Study drug will be taken once daily from Day l through Day 504 as described in Section 8.2. 
o 
Adverse event information will be collected from the time of signing of the informed consent form to study discontinuation. 
p 
For hepatic adverse events and/or hepatic decompensation, a PK sample should be collected as close to the onset of the event as possible (PK samples not required 
during screening period). 
q 
Dosage form acceptability questions will be asked of the caregiver and/or patient at Visits 3, 6, and 11. 
r 
Patient/Caregiver/Clinician Patient Global Impression of Change not applicable for Cohort 2. 

A4250 – IND 130591 
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Module 5: Clinical Study Reports 
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Amendment 6.2 Sweden, 11 February 2022
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7.1.3
Study Procedures and Assessments
When the COVID-19 pandemic makes it challenging for a patient to attend a visit at the study 
center and where applicable country and local regulations and infrastructure allow, routine 
assessments may be performed outside of the study center (e.g., the patient’s home) by a trained 
healthcare professional at all timepoints following the Inclusion Visit (Visit 1). These 
assessments can include the following: vital signs, height and weight, mid-arm circumference, 
body assessement, blood draws, urine collection, and urine pregnancy test. All laboratory 
samples should be sent to the central laboratory; an exception is for situations related to the 
COVID-19 pandemic if central laboratory assessments are not possible, then a local laboratory 
may be used. These local laboratory results must be sent to the site for review by the
investigator and submitted to iRIS (ICON Results Integration Services). Collection of other
visit requirements, e.g., concomitant medication and AE collection associated with visits
outside of the clinic will be collected by qualified site staff through verbal contact with the 
patient.
For any study visit, the study physician (or delegate) must, at a minimum, verbally contact the 
patient within the expected window for each study visit to collect relevant safety information 
(including, but not limited to, AEs, concomitant medications, hospitalizations/procedures, and 
vital status). Any missed assessment due to a study visit being performed outside of the study 
center will be considered a protocol deviation.
7.1.3.1
Screening Period (Days -56 to 0) (For Cohort 2 only)
If the screening period is expected to be prolonged due to COVID-19 related issues, site follow- 
up with the medical monitor and investigator is required to determine if the screening period
can be extended for another two weeks. Determination will be assessed on a case-by-case basis. 
During this allowed two-week extension period, it is anticipated that no additional testing and 
assessments will be required. If the screening period is extended beyond two weeks, additional 
assessments, including but not limited to safety labs, will be required.
Day -56 to Day -35/Clinic Visit S-1 
Cohort 2 patients will undergo a Screening Visit up to 56 days prior to the planned first day of 
study treatment. Screening procedures and assessments are as follows:
Obtain written informed consent
Assess inclusion/exclusion criteria (Section 7.2)
Record demographics
Document concomitant medications
Medical and surgical history (date of diagnosis of PFIC Type, prior investigational 
medications for PFIC, historical liver function test [LFT] values, any surgery performed,
any other diagnosis, and historical liver biopsy data) 

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Confidential
Amendment 6.2 Sweden, 11 February 2022
38
For patients with episodic forms of PFIC (i.e., BRIC), collect information on frequency, 
duration, and severity of flares within the last 6 months at a minimum, and within the last 
5 years, if possible. If available, historical data on serum bile acid levels and pruritus should 
be collected
Collect, if available, past confirmatory clinical genetic laboratory report for PFIC, 
including BRIC, type and send to central reader for review. If a historical report is 
equivocal, unavailable, or unobtainable, a blood sample for clinical genetic testing will be 
collected to determine eligibility (Section 10.2.4)
Physical examination (Section 10.2.5) and vital signs (Section 10.2.6)
Skin examination (Section 10.2.5)
eDiary training and compliance requirements; caregivers and/or patients begin daily 
recording of pruritus using the eDiary (Appendix 2)
Clinical chemistry (Section 10.2.1)
Serum bile acids (Section 9.2.1)
Serum pregnancy test for girls who have reached menarche. Please see Appendix 6 for 
contraceptive requirements
AE monitoring
Day -28 to Day -7/Clinic Visit S-2 
A second Screening Visit will be performed for patients in Cohort 2. Screening procedures 
and assessments are as follows:
Review concomitant medications 
 
Vital signs (Section 10.2.6)
Albireo PRO/ObsRO eDiary review for compliance
Serum bile acids (Section 9.2.1)
International normalized ratio (INR)
Urine pregnancy test for girls of who have reached menarche
 
AE monitoring 
Clinical chemistry retest (if applicable)
7.1.3.2
Treatment Period 
Study Day 1/Visit 1
For Cohort 1, patients will undergo a Screening/Inclusion Visit that coincides with Visit 9 of 
Study A4250-005. 

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For Cohort 1: Obtain written informed consent
For Cohort 2: Albireo PRO/ObsRO eDiary review for compliance and eligibility criteria (see 
Inclusion Criteria 4 [Cohort 2, excluding BRIC], Section 7.2.1). 
The following procedures will be conducted for both cohorts:
Assess inclusion/exclusion criteria (Section 7.2)
Document concomitant medications
Physical examination (Section 10.2.5) and vital signs (Section 10.2.6)
Skin examination (Section 10.2.5)
Albireo PRO/ObsRO eDiary training, compliance requirements, and instructions to 
continue recording of pruritus (Appendix 2)
Clinical chemistry, hematology, and urinalysis (Section 10.2.1)
Serum bile acids (Section 9.2.1)
p-C4 and autotaxin
Alfa-fetoprotein (AFP)
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1) 
Abdominal ultrasound (Section 10.2.7)
Fibroscan, where available (Section 9.2.8)
Administer QoL (Pediatric Quality of Life Inventory [PedsQL]) questionnaire
Serum pregnancy test for girls who have reached menarche (only for patients in Cohort 1).
Please see Appendix 6 for contraceptive requirements
Patient/caregiver/clinician complete the patient global impression of symptoms (PGIS) and 
the patient global impression of change (PGIC) 
AE monitoring
Study drug is dispensed
Week 4/Visit 2 
The following procedures and assessments will be conducted: 
Document concomitant medications
Vital signs (Section 10.2.6)
Skin examination (Section 10.2.5)
Albireo PRO/ObsRO eDiary review for compliance

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Clinical chemistry and hematology (Section 10.2.1)
INR
Serum bile acids (Section 9.2.1)
p-C4 and autotaxin 
Patient/caregiver/clinician complete the PGIS and the PGIC
Urine pregnancy test for girls who have reached menarche
AE monitoring
Evaluation of study drug compliance 
 
Study drug is dispensed 
Week 8/Telephone contact 1 
A study nurse will contact patients via telephone for AE monitoring 4 weeks after Visit 2,
at Week 8
Week 12/Visit 3 
As of Protocol Amendment 6.2 Sweden, patients entering Cohort 2 will start treatment at 
40 µg/kg/day with the possibility to dose escalate to 120 µg/kg/day after 12 weeks (Visit 3) if 
there is no improvement in pruritus based on investigator judgment. 
The following procedures and assessments will be conducted (all patients): 
Document concomitant medications
Physical examination (Section 10.2.5) and vital signs (Section 10.2.6)
Skin examination (Section 10.2.5)
Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry and hematology (Section 10.2.1) 
INR
Serum bile acids (Section 9.2.1)
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1) 
Patient/caregiver/clinician complete the PGIS and the PGIC
Urine pregnancy test for girls who have reached menarche
AE monitoring
Evaluation of study drug compliance; dosage form acceptability questions will be asked of 
the caregiver and/or patient

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Study drug is dispensed
Week 18/Telephone contact 2 
A study nurse will contact patients via telephone for AE monitoring 6 weeks after Visit 3,
at Week 18
Weeks 22 and 46/Visits 4 and 7 
The following procedures and assessments will be conducted: 
Document concomitant medications
Vital signs (Section 10.2.6)
Albireo PRO/ObsRO eDiary review for compliance
INR
Serum bile acids (Section 9.2.1)
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1)
Urine pregnancy test for girls who have reached menarche
 
AE monitoring 
Weeks 24 and 48/Visits 5 and 8 
The following procedures and assessments will be conducted:
Document concomitant medications
Skin examination (Section 10.2.5)
Physical examination (Section 10.2.5) and vital signs (Section 10.2.6)
Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry, hematology, and urinalysis (Section 10.2.1) 
Serum bile acids (Section 9.2.1)
p-C4 and autotaxin 
AFP
Abdominal ultrasound (Section 10.2.7)
Fibroscan, where available (Section 9.2.8)
Administer PedsQL questionnaire
Patient/caregiver/clinician complete the PGIS and the PGIC
Urine pregnancy test for girls who have reached menarche
AE monitoring

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Evaluation of study drug compliance 
 
Study drug is dispensed 
Weeks 30 and 54/Telephone contacts 3 and 5 
A study nurse will contact patients via telephone for AE monitoring 6 weeks after Visits 5 
and 8, at Weeks 30 and 54, respectively 
Weeks 36 and 60/Visits 6 and 9 
The following procedures and assessments will be conducted:
Document concomitant medications 
Vital signs (Section 10.2.6)
Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry and hematology (Section 10.2.1)
INR
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1) 
Serum bile acids (Section 9.2.1)
Urine pregnancy test for girls who have reached menarche
 
AE monitoring 
Evaluation of study drug compliance; dosage form acceptability questions will be asked of 
the caregiver and/or patient (only at Visit 6) 
Study drug is dispensed
Weeks 42 and 66/Telephone contacts 4 and 6 
A study nurse will contact patients via telephone for AE monitoring 6 weeks after Visits 6 
and 9, at Weeks 42 and 66, respectively 
Week 70/Visit 10
The following procedures and assessments will be conducted: 
Document concomitant medications
Vital signs (Section 10.2.6)
Albireo PRO/ObsRO eDiary review for compliance
Serum bile acids (Section 9.2.1)
INR
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1)

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Urine pregnancy test for girls who have reached menarche
 
AE monitoring 
7.1.3.3
End of Treatment/Early Termination 
Week 72/Visit 11
The last dose of study drug will be administered in the morning the day before the visit and the 
following assessments will be performed:
Document concomitant medications
Physical examination (Section 10.2.5) and vital signs (Section 10.2.6)
Skin examination (Section 10.2.5)
Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry, hematology, and urinalysis (Section 10.2.1)
Serum bile acids (Section 9.2.1)
p-C4 and autotaxin 
AFP
Abdominal ultrasound (Section 10.2.7)
Fibroscan, where available (Section 9.2.8)
Administer PedsQL questionnaire
Urine pregnancy test for girls who have reached menarche
Patient/caregiver/clinician complete the PGIC and PGIS
AE monitoring
Evaluation of study drug compliance; dosage form acceptability questions will be asked of 
the caregiver and/or patient
Liver biopsy (if required; see Section 9.2.10)
7.1.3.4
Follow-up Visit
Week 76/Visit 12
Patients will return to the study site 28 days after Visit 11 or the last dose of study drug (for 
those patients who prematurely withdraw) for the following assessments: 
Document concomitant medications 
Vital signs (Section 10.2.6) 
Albireo PRO/ObsRO eDiary review for compliance

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Clinical chemistry and hematology (Section 10.2.1)
INR
Serum bile acids (Section 9.2.1)
Urine pregnancy test for girls who have reached menarche 
AE monitoring 
7.2
Study Population
Cohort 1 will consist of approximately 60 children who completed 24 weeks, or who withdrew 
after a minimum of 12 weeks of treatment due to intolerable symptoms in Study A4250-005 
and meeting all inclusion criteria and no exclusion criteria are eligible for this study. Patients 
who withdraw from A4250-005 due to a study drug related AE will not be eligible. 
Cohort 2 will consist of approximately 60 patients with any type of PFIC who have elevated 
serum bile acids and cholestatic pruritus and who either (1) do not meet eligibility criteria for 
Study A4250-005 (PEDFIC 1) or (2) do meet the eligibility criteria for A4250-005 after 
recruitment of study A4250-005 has been completed. Up to 40 patients post biliary diversion 
surgery are allowed to participate in Cohort 2.
7.2.1
Inclusion Criteria
Cohort 1:
1. Completion of the 24-week Treatment Period of Study A4250-005 or withdrawn from
Study A4250-005 due to patient/caregiver judgment of intolerable symptoms after 
completing at least 12 weeks of treatment. Patients who withdraw from A4250-005 due to
a study drug related AE will not be eligible. 
2. Signed informed consent and assent as appropriate. Patients who turn 18 years of age (or 
legal age per country) during the study will be required to re-consent to remain on the study. 
3. Patients expected to have a consistent caregiver for the duration of the study.
4. Caregivers (and age-appropriate patients) must be willing and able to use an eDiary device 
as required by the study. 
Cohort 2:
1. A male or female patient of any age, with a clinical diagnosis of PFIC, including episodic 
forms (i.e., BRIC), and with a body weight 5 kg at Visit S-1.
2. Patient must have clinical genetic confirmation of PFIC.
3. Patients with PFIC, excluding BRIC, must have elevated serum bile acid concentration, 
apart (Visits S-1 and S-2) prior to the Screening/Inclusion Visit (Visit 1).

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4. Patients with PFIC, excluding BRIC, must have history of significant pruritus and a 
caregiver-reported observed scratching or patient-reported itching (for patients >18 with no 
caregiver-reported observed scratching) 
2 weeks prior to the Screening/Inclusion Visit (Visit 1). 
5. Patients with episodic forms of PFIC (i.e., BRIC) must have an emerging flare
characterized by clinically significant pruritus and elevated serum bile acid
levels/cholestasis as judged by the investigator.
6. Patient and/or legal guardian must sign informed consent (and assent) as appropriate. 
Patients who turn 18 years of age (or legal age per country) during the study will be required 
to re-consent in order to remain in the study. 
7. Age appropriate patients are expected to have a consistent caregiver for the duration of the 
study.
8. Caregivers and age-
, if able) must be willing and able 
to use an eDiary device as required by the study. 
7.2.2
Exclusion Criteria
Patients meeting any of the following criteria at Visit 1 or Visit S-1 will not be eligible for 
study participation:
Cohort 1:
1. Decompensated liver disease: coagulopathy, history, or presence of clinically significant 
ascites, variceal hemorrhage, and/or encephalopathy. 
2. Sexually active males and females who are not using a reliable contraceptive method with
-uterine device, or complete 
abstinence) throughout the duration of the study and 90 days thereafter (from signed 
informed consent through 90 days after last dose of study drug). See Appendix 6 for further 
details.
3. Patients not compliant with treatment in study A4250-005.
4. Any other conditions or abnormalities which, in the opinion of the investigator or Medical 
Monitor, may compromise the safety of the patient, or interfere with the patient
participating in or completing the study. 
Cohort 2:
1. Known pathologic variations of the ABCB11 gene that have been demonstrated to result 
in complete absence of the BSEP protein.
2. Patient with past medical history or ongoing presence of other types of liver disease 
including, but not limited to, the following: 
a) Biliary atresia of any kind.

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b) Suspected or proven liver cancer or metastasis to the liver on imaging studies.
c) Histopathology on liver biopsy is suggestive of alternate non-PFIC related etiology of
cholestasis.
Note: Patients with clinically significant portal hypertension are allowed.
3. Patient with a past medical history or ongoing presence of any other disease or condition 
known to interfere with the absorption, distribution, metabolism (specifically bile acid 
metabolism), or excretion of drugs in the intestine, including but not limited to, 
inflammatory bowel disease.
4. Patient with past medical history or ongoing chronic (i.e., >3 months) diarrhea requiring 
intravenous fluid or nutritional intervention for treatment of the diarrhea and/or its 
sequelae.
5. Patient has a confirmed past diagnosis of infection with human immunodeficiency virus 
or other present and active, clinically significant, acute, or chronic infection, or past 
medical history of any major episode of infection requiring hospitalization or treatment 
with parenteral anti-infective treatment within 4 weeks of treatment start (Study Day 1) or 
completion of oral anti-infective treatment within 2 weeks prior to start of Screening
Period.
6. Any patient with suspected or confirmed cancers except for basal cell carcinoma, and 
non-liver cancers treated at least 5 years prior to Screening with no evidence of recurrence.
7. Patient has had a liver transplant, or a liver transplant is planned within 6 months of the 
Screening/Inclusion Visit. 
8. Decompensated liver disease, coagulopathy, history, or presence of clinically significant 
ascites, variceal hemorrhage, and/or encephalopathy. 
9. INR >1.4 (the patient may be treated with Vitamin K intravenously, and 
resampling the patient may be included).
10. Serum ALT >10 × upper limit of normal (ULN) at Screening.
11. Serum ALT >15 × ULN at any time point during the last 6 months unless an alternate 
etiology was confirmed for the elevation. 
12. Total bilirubin >10 × ULN at Screening.
13. Patient suffers from uncontrolled, recalcitrant pruritic condition other than PFIC. 
Examples include, but not limited to, refractory atopic dermatitis or other primary pruritic 
skin diseases.
14. Any patient who is pregnant or lactating or who is planning to become pregnant within 
72 weeks of the Screening/Inclusion Visit. 

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15. Sexually active males and females who are not using a reliable contraceptive method with
abstinence) throughout the duration of the study and 90 days thereafter (from signed 
informed consent through 90 days after last dose of study drug). See Appendix 6 for 
further details.
16. Patient with a past medical history of alcohol or substance abuse will be excluded. 
Patient must agree to refrain from illicit drug and alcohol use during the study. 
17. Administration of bile acid or lipid binding resins and medications that slow GI motility 
(Refer to Appendix 1 – Concomitant Medications Guidelines).
18. Patient has had investigational exposure to a drug, biologic agent, or medical device
within 30 days prior to Screening, or 5 half-lives of the study agent, whichever is longer. 
19. Any other conditions or abnormalities which, in the opinion of the investigator or Medical 
Monitor, may compromise the safety of the patient, or interfere with the patient
participating in or completing the study. 
7.2.3
Withdrawal of Patients
Patients/caregivers will be informed that they have the right to withdraw from the study at any 
time, without prejudice to their medical care, and that they are not obliged to state their reasons.
Any withdrawal, and reasons for withdrawal, must be fully documented in the eCRF and source 
documents and the patient followed by the investigator/investigative staff. Withdrawn patients 
will not be replaced.
Patients will be withdrawn in the following circumstances:
A patient’s/caregiver’s desire for withdrawal for any reason
Lost to follow-up (every effort must be made to contact the patient/caregiver; a certified 
letter must be sent)
An AE which, in the opinion of the investigator, necessitates withdrawal
Death
A patient’s/caregiver’s substantial non-compliance (eDiary and study drug compliance) or 
protocol violation
An investigator’s opinion that continuing the patient in the study is not appropriate. The 
investigator may withdraw a patient at any time, if it is considered to be in the patient’s best 
interest
Liver transplantation
The reason and the date the patient is withdrawn from the study will be documented in the
eCRF and source documents. If a patient is withdrawn from further treatment with the study

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drug, the investigator/investigative staff will attempt to complete all Visit 11 procedures at the 
time the patient is prematurely withdrawn from the study. The investigator/investigative staff 
will also attempt to complete all Visit 12 procedures 28 days following premature withdrawal 
(i.e., 28 days following the final dose of the study drug). 
If a patient discontinues prior to Week 72, additional telephone contacts will be made every 
3 months after the Follow-up Visit (Visit 12) up to Week 72 to gather whether or not the patient 
has had biliary diversion or liver transplantation, and of ongoing TEAEs at the time of 
discontinuation have resolved. The telephone calls will take place up until 72 weeks even if the 
patient has biliary diversion or liver transplant. 
7.2.4 
Study Termination by Sponsor 
This study may be terminated at any time by Albireo if significant safety concerns develop or, 
in the sponsor’s judgment, there are no further benefits to be achieved from continuation of the 
study. In this event, Albireo/designee will inform the study investigators, institutions and all 
regulatory authorities. 
Albireo may temporarily or permanently discontinue the study at an investigative site at any 
time for safety, ethical, compliance or other reasons. If this is necessary, Albireo will endeavor 
to provide advance notification to the site. If a site or the study is suspended or discontinued, 
the investigator/investigative staff will be responsible for promptly informing the Independent 
Ethics Committee (IEC)/Institutional Review Board (IRB) that this has happened. If required 
by local regulations, Albireo/designee will be responsible for informing the IEC/IRB and the 
Regulatory Authority of study or site discontinuation. In such an event, all study data and 
unused study drug must be returned to Albireo. 

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8
TREATMENT OF PATIENTS
8.1
Identity of Study Drug
A4250 will be supplied as capsules for oral administration. White opaque capsules filled with 
pellets containing A4250 will be provided. Two different capsule sizes will be available:
Capsule size 0 that can be opened
Capsule size 3 that should be swallowed intact. The size 3 capsules may be opened
only under exceptional circumstances, e.g., patient cannot swallow the capsule intact. 
Bottles with 34 capsules will be given to the patient at each visit. A patient who requires 2 or 
more capsules per day will be given multiple bottles. Refer to the Investigational Product 
Manual.
A 5-digit study drug number will identify study drug packs and will be detailed on the study 
drug label. Dispensing of study drug will be coordinated by the Interactive Web Response 
System (IWRS). The system will assign study drug number(s) using a packing list based on 
the patient’s weight and dose level (either 120 µg/kg/day or 40 µg/kg/day) for dispensation at 
each dispensing visit. In case of technical issues accessing the system online, please see the 
IWRS site user manual for country-specific contact telephone numbers to the ICON HelpDesk 
24/7 system support. 
8.2
Administration of Study Drug
Patients will be dosed with 120 µg/kg/day or 40 µg/kg/day4 for 72 weeks or 40 µg/kg/day for
the first 12 weeks followed by 120 µg/kg/day for the remaining 60 weeks4. Patients not 
tolerating the 120 µg/kg/day dose after a minimum of 1 week, for reasons other than new liver 
findings and severe diarrhea, will have the option to down-titrate to a lower dose 
(40 µg/kg/day). They should return to the higher dose as soon as deemed appropriate by the 
investigator.  More than one upward dose titration (from 40 µg/kg/day directly to
120 µg/kg/day) for the same event is not recommended. If, in the opinion of the investigator, 
a dose titration should be considered prior to the 1 week minimum, the investigator should 
consult with the Medical Monitor or designee.
Any dose titration should be done in 
consultation with the sponsor Medical Monitor or designee. 
Study drug will be dispensed to the patient at defined intervals from Visit 1 through Visit 9, 
together with instructions on how to store and take the drug. Study drug administration data, 
including whether each patient took each dose or partial doses of study drug, whether there
were any delayed or missed doses, and whether the capsule was opened or swallowed whole, 
will be documented through the diaries and transferred to the study database. 
4 As of Protocol Amendment 6.2 Sweden patients entering Cohort 2 will start treatment at 40 µg/kg/day 
with the possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus 
based on investigator judgment.

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A4250 should be taken in the morning together with food. On clinic visits days when 
laboratory assessments are conducted (Visits 1 to 10), study drug should be taken after the visit. 
Patients should not crush or chew the capsule(s). When swallowing the capsule intact, the 
patient should administer the dose with a glass of water. 
If the study medicine needs to be mixed in a small amount of food because the patient is unable 
to swallow the capsule intact, the capsule can be twisted open and the contents sprinkled and 
mixed in a small amount (one or two tablespoons (15 to 30 mL)) of room-temperature yogurt, 
apple sauce, oatmeal, or fruit purée. If the patient has not yet been weaned onto solid foods, 
the capsule contents can be sprinkled into a small amount (a few milliliters) of water, baby 
formula or breast milk and administered with an oral dosing pipette. Please see Pharmacy 
manual for detailed instructions. 
If a patient’s weight changes at any time during the study, dose adjustment will be required. 
The number of capsules provided to the patient should be based on the body weight thresholds 
identified in Table 2. 

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Table 2 
Dosing and Capsule Strength 
 
Body 
Weight (kg) 
Capsule 
Size 
Number of 
Capsules 
per Daya,b 
Capsule 
Strength, 
Low Dosea 
(µg) 
Total Dose 
(µg) a 
Capsule 
Strength, 
High Doseb 
(µg) 
Total Dose 
(µg) b 
5 to <7.5 
0 
1 
200 
200 
600 
600 
7.5 to <12.5 
0 
2 
200 
400 
600 
1200 
12.5 to <17.5 
0 
3 
200 
600 
600 
1800 
17.5 to <19.5 
0 
4 
200 
800 
600 
2400 
19.5 to <25.5 
3 
2 
400 
800 
1200 
2400 
25.5 to <35.5 
3 
3 
400 
1200 
1200 
3600 
35.5 to <45.5 
3 
4 
400 
1600 
1200 
4800 
45.5 to 55.5 
3 
5 
400 
2000 
1200 
6000 
>55.5 
3 
6 
400 
2400 
1200 
7200 
a Low dose: 40 µg/kg/day 
b High dose: 120 µg/kg/day 

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8.3 
Study Drug Packaging and Labelling 
8.3.1 
Packaging and Labelling 
The capsules will be packed in high-density polyethylene containers, with childproof 
polypropylene caps. Study drug capsules containing A4250 in the strength specified in the 
table above will be manufactured. 
Packaging and labelling will be prepared to comply with applicable regulatory requirements. 
8.3.2 
Storage 
Treatment packs containing A4250 capsules should be stored and dispensed in accordance with 
regulations in their original containers. The storage facility at the investigative site should be 
locked and storage should be between 15°C and 25°C. 
Patients/caregivers should be informed of appropriate storage conditions (i.e., room 
temperature, between 15°C and 25°C). 
Any deviations from the recommended storage conditions should be immediately reported to 
Albireo and the study drug should not be used until authorization has been given by Albireo. 
8.3.3 
Blinding and Randomization of Study Drug 
Not applicable. 
8.4 
Procedure for Breaking the Randomization Code 
Not applicable. 
8.5 
Patient Compliance 
The study nurse will monitor eDiary compliance by routine review of the CRF Health website. 
Patient/caregivers will be instructed to fill in the eDiary every morning and evening for the first 
24 weeks and the last 21 days before all the remaining visits to the clinic. There will be no 
interruption between Visits 11 and 12. If both diary entries on a day are missing during this 
time, the study nurse will call the caregiver/patient to remind them to complete all scheduled 
entries. Any non-compliance will be documented and explained in the source documents. 
Study drug compliance will be assessed by review of returned unused medication and by 
counting returned capsules at Visits 2 through 11, inclusive. Study drug compliance will be 
calculated for each patient and listed. 
Treatment Compliance = 100 × ((Number of study drug dispensed - number of study drug 
returned)/number of study drug that should be taken) 
Treatment compliance between 80% and 120% will be acceptable. 

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8.6 
Patient Identification 
After written informed consent is obtained from an eligible patient, an 8-digit patient 
identification number will be assigned. The first 2 digits will denote the country, followed by 
a 3-digit site number and a 3-digit patient sequence number. This number will be captured by 
the IWRS, when the patient first enters the system in A4250-008. Cohort 1 patients will be 
assigned the same patient number as used in the A4250-005 study, while Cohort 2 patients will 
be assigned a new unique patient number. 
8.7 
Study Drug Accountability 
Records shall be maintained of the delivery of study treatment to the study site(s), the inventory 
at the study site(s), the use of each patient and the return to Albireo. 
These records shall include dates, quantities, batch numbers, expiry dates and the unique code 
numbers assigned to the study drug and to the study patients. 
The investigator will be responsible for ensuring that the records adequately document that the 
patients were provided the quantities specified in the protocol and that all study drug received 
from Albireo is reconciled. 
8.8 
Concomitant Therapy and Prohibited Medications 
For Cohort 1 patients, the investigator will note all ongoing medication in the eCRF at Visit 1. 
For Cohort 2 patients, the investigator will note all ongoing medication and any medication 
recently stopped (within 1 month prior to Visit S-1) in the eCRF at Visit S-1. At Visits 2 to 
12, (and S-2 for Cohort 2) all changes in medication (stopping or starting new medication or 
changes in dose) will be recorded in the eCRF. All medication (prescribed or over the counter) 
for pruritus, sleep, and vitamin supplementation will be recorded. 
All medications still being taken by a patient on or after first intake of study drug and which 
continue to be taken during the study are regarded as concomitant medication. 
The protocol allows for patients to be vaccinated against COVID-19 while in the study, based 
on the treating physician’s clinical assessment of the risks and benefits of study participation. 
Therefore, the COVID-19 vaccine can be administered as a concomitant medication. The date 
of COVID-19 vaccination must be recorded in the clinical database if administered during 
study participation. 
Concomitant medication guidelines are listed in Appendix 1. 

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9
ASSESSMENT OF EFFICACY
9.1
Efficacy Endpoints
9.1.1
Primary Efficacy Endpoints
The primary efficacy endpoints are:
EU and rest of world: Change from baseline in serum bile acids after 72 weeks of treatment.
US: Proportion of positive pruritus assessments at the patient level over the 72-week treatment 
period using the Albireo ObsRO instrument. 
9.1.2
Secondary Efficacy Endpoints
EU and rest of world: Proportion of positive pruritus assessments at the patient level over 
the 72-week treatment period using the Albireo ObsRO instrument. 
US: Change from baseline in serum bile acidsafter 72 weeks of treatment.
All Regions:
Change from baseline in serum bile acids at Weeks 4, 12, 22, 24, 36, 46, 48, 60, 70, 72, and
76
Proportion of individual assessments meeting the definition of a positive pruritus
assessment at the patient level using the Albireo ObsRO instrument from Weeks 0-4, 
Weeks 0-12, Weeks 0-22, Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, 
Weeks 0-60, and Weeks 0-70, respectively, or the proportion of positive pruritus 
assessments at each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then
by each visit between Visit 5/Week 24 to Visit 12/Week 76 
Proportion of individual AM assessments meeting the definition of a positive pruritus 
assessment at the patient level using the Albireo ObsRO instrument from Weeks 0-4, 
Weeks 0-12, Weeks 0-22, Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, 
Weeks 0-60, Weeks 0-70, and Weeks 0-72, respectively, or the proportion of positive 
pruritus  assessments
at  each
4-week
interval  between
Visit
1/Screening
and 
Visit 5/Week 24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 
Proportion of individual PM assessments meeting the definition of a positive pruritus 
assessment at the patient level using the Albireo ObsRO instrument from Weeks 0-4, 
Weeks 0-12, Weeks 0-22, Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, 
Weeks 0-60, Weeks 0-70, and Weeks 0-72, respectively, or the proportion of positive 
pruritus  assessments
at  each
4-week
interval  between
Visit
1/Screening
and 
Visit 5/Week 24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 
All-cause mortality, number of patients undergoing biliary diversion surgery or liver 
transplantation. These parameters will be evaluated separately and together at weeks 24,
48, and 72 

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Change in growth from baseline to Weeks 24, 48, and 72 after initiation of A4250
treatment, defined as the linear growth deficit (height/length for age, weight for age, mid- 
arm circumference, and body mass index [BMI]) compared to the standard growth curve
(Z-score, standard deviation [SD] from P50) 
Change in AST to platelet ratio index (APRI) score and Fib-4 score from baseline to Week 
72
Change in pediatric end-stage liver disease (PELD)/model for end-stage liver disease 
(MELD) score from baseline to Week 72
Change in use of antipruritic medication at Weeks 24, 48, and 72
9.1.3
Exploratory Efficacy Endpoints
All Exploratory Endpoints will be evaluated at Weeks 24, 48, and 72 unless otherwise noted. 
Baseline is calculated prior to initiation of A4250 treatment. Exploratory endpoints include:
Change in serum ALT, GGT, and total bilirubin concentration from baseline to Week 72
Proportion of individual assessments meeting the definition of a positive pruritus
assessment at the patient level over the 72-week Treatment Period. A positive pruritus 
assessment includes an itch score 
-point drop from baseline based on
the Albireo PRO instrument; 
instrument
Change from baseline over the 72-week treatment period in sleep parameters measured
with the Albireo PRO and ObsRO instruments
Change from baseline in INR, albumin, liver enzymes, leukocytes, and platelets
Change from baseline measures of bile acid synthesis (autotaxin, p-C4)
Assessment of Global Symptom Relief at Weeks 4, 12, 24, 48, and 72 as measured by 
patient, caregiver, and clinician PGIC items
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 
24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 in patient-reported and 
observer-reported night time itching and scratching severity scores, respectively
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 
24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 in patient-reported and 
observer-reported morning time itching and scratching severity scores, respectively
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 
24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 in pooled pruritus
score including observer-reported scratching for patients <8 years of age and patient- 
years of age

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Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 
24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 in additional patient- 
reported and observer-reported sleep parameters (e.g., tiredness, number of awakenings) 
Change from baseline in PedsQL questionnaire
Change from baseline in stage of liver fibrosis as assessed by Fibroscan® (where available)
Change from baseline in stage of liver fibrosis as assessed by post-treatment biopsy (when 
available)
9.2
Efficacy Assessments
9.2.1
Serum Bile Acids
Blood samples for analysis of fasting serum bile acids will be drawn at all study visits from
Visit 1 (Visit S-1 for Cohort 2) through Visit 12. Patients will fast (only water intake is 
permissible) for at least 4 hours prior to the collection of samples for serum bile acids. 
Exceptions can be made for infants, less than 12 months of age, if unable to fast for the full 4 
hours. For any visit at which a bile acid sample result is unreportable, an additional 
unscheduled visit for a repeat sample collection may be scheduled. Samples will be handled 
and transported to a central laboratory per instructions in the laboratory manual. 
9.2.2
Itching and Sleep Score
Itching, observed scratching, and sleep disturbance will be assessed twice each day via eDiary. 
Patient/caregivers will be instructed to fill in the eDiary every morning and evening for the first 
24 weeks and the last 21 days before all the remaining visits to the clinic. There will be no 
interruption between Visits 11 and 12. Patients and/or caregivers will be instructed to complete 
the eDiary in the morning after the patient wakes and in the evening just before the patient goes 
to sleep. 
The eDiary includes Albireo ObsRO and PRO items. Patients <8 years of age will not be asked 
to complete the Albireo PRO items; only the Albireo ObsRO will be completed by caregivers 
o 
items and the caregiver will complete the Albireo ObsRO items. The Albireo PRO items assess 
severity of itch, aspects of sleep disturbance (morning diary only), and tiredness. For patients 
8 to 12 years of age, the caregiver will read the Albireo PRO items along with the child and 
record the child’s response. A guide will be provided to the caregivers that provides 
standardized explanations of the Albireo PRO items, in case the patient is confused or requires 
clarification about the meaning of a question. The Albireo ObsRO items assess severity of 
observed scratching, aspects of observed sleep disturbance (morning diary only), and observed 
signs of tiredness (evening diary only). The Albireo ObsRO and PRO scratching and itch 
severity items use 0 to 4 response scales, where each response is distinguished by a unique
facial expression, verbal anchor, number, and color code (Appendix 2). 

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A daily score AM and PM for the Albireo ObsRO scratching item will be averaged from the 
2 ratings for each day. A daily score will be considered missing if both of the daily
assessments are missing. A weekly score will be calculated by averaging the daily scratching 
scores. A weekly score will be considered missing if 4 out of 7 days a week of data are 
missing. For AM and PM baseline, a 14-day daily score of AM and PM prior to the first dose 
of study medication will be averaged as the baseline score. 
For AM baseline, a 14-day AM score prior to the first dose of study medication will be 
averaged as the baseline AM score. The same approach will be used for PM baseline and to 
calculate a patient-reported itch severity score.
9.2.3
Growth
Growth (height and weight) will be measured by the standardized assessments outlined in the 
US FDA guidance document, Orally Inhaled and Intranasal Corticosteroids: Evaluation of the 
Effects on Growth in Children (March 2007). Height and length (velocity) will be measured 
using a certified stadiometer and weight (Z-score) using a certified weight scale.
Mid-arm circumference (3 repeat measurements) will be collected at the study site.
Study sites will be trained on using a standardized approach when measuring height with a 
stadiometer and additional detailed instructions will be provided in study documents. 
BMI will be calculated by weight (kg) / height (m)2. Change will be defined as linear growth 
deficit (weight and BMI for age) compared to a standard growth curve. 
9.2.4
Biomarker Samples
Blood samples for p-C4 and autotaxin will be drawn at Visits 1, 2, 5, 8, and 11 (p-C4 and 
autotaxin will only be drawn for patients with body weight >10 kg). Samples will be treated 
and transported to a central laboratory per instructions in the laboratory manual. 
9.2.5
Change of Antipruritic Medication
Any change of antipruritic medication must be noted in the eCRF.
9.2.6
Quality of Life Questionnaire (PedsQL)
Caregivers and, if applicable, patients will be asked to fill out a QoL questionnaire (PedsQL) 
at Visits 1, 5, 8, and 11. Details of the questions included on the questionnaire can be found in 
Appendix 4.
9.2.7
PELD/MELD Score
The PELD score will be calculated for children up to 12 years of age. For patients 13 years or 
older, the MELD score will be calculated.
PELD Score = 4.80 * ln(total bilirubin) + 18.57 * ln(INR) - 6.87 * ln(albumin) + 4.36 (if patient
<1 year: scores for patients listed for liver transplantation before the patient’s first birthday

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continue to include the value assigned for age (<1 year) until the patient reaches the age of 24 
months) + 6.67 (if patient has growth failure [<-2 SD])
Laboratory values less than 1.0 will be set to 1.0 for the calculation of the PELD score. 
MELD Score = 9.57 * ln(creatinine) + 3.78 * ln(total bilirubin) + 11.2 * ln(INR) + 6.43 
Laboratory values less than 1.0 will be set to 1.0 and serum creatinine values greater than
4.0 mg/dL (equivalent to 353.6 µmol/L) will be set to 4.0 for calculation of the MELD score.
If a patient goes from 11 years of age to 12 between the beginning and end of study, both PELD 
and MELD scores will be calculated at the first visit after the 12th birthday and move to MELD 
score. The results should be displayed in one summary table. 
9.2.8
Fibroscan®
Where available, Fibroscan® will be performed as per institution standard practice at Visits 1, 
5, 8, and 11. 
9.2.9
Markers of Fibrosis
APRI score and Fib-4 score will be calculated at Visits 1, 3, 5, 8, and 11.
APRI = [(AST in U/L) / (AST upper limit of normal [ULN] in U/L)] x 100 / (Platelets in 109/L) 
Fibrosis 4 Score = (Age*AST in U/L) / (Platelets in 109/L *  (ALT in U/L))
9.2.10
Liver Biopsy
If a liver biopsy is performed according to the local regulations or standard of care at any time 
during A4250-008, the biopsy results should be recorded in the eCRF. If the patient has liver 
biopsy results collected in study A4250-005 or prior to Week 24 in study A4250-008, the
patient will be asked to consent to a follow up liver biopsy, if allowed per local regulations, at 
Visit 11 unless 2 prior liver biopsy results have been collected with at least 1 year between 
biopsies. Liver biopsies will not be performed in Spain. 
9.2.11
Global Impression of Change and Global Impression of Symptom Measures
Patients, caregivers, and clinicians will complete the PGIC and the PGIS measures at Visits 1,
2, 3, 5, 8, and 11 (Appendix 3). 
The PGIC items assess change in itch (patient version), scratching (caregiver and clinician 
versions), and sleep (all versions) since starting the study drug. The PGIS items assess itch 
(patient version), scratching (caregiver and clinician versions), and sleep (all versions) in the 
past week. Caregivers and clinicians will complete the PGIC and PGIS for all patients; those 
years of age will complete the patient version.

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10
ASSESSMENT OF SAFETY
The timing and frequency of safety assessments are described in Section 7.1.2 and 
Section 7.1.3.
The primary safety analysis for this study will include the incidence of total treatment-emergent 
adverse events (TEAE) and TEAEs categorized by causality, severity, and seriousness 
assessments.
Trends in safety will also be evaluated for the following assessments:
Physical examinations
Concomitant medications 
Vital signs
Laboratory test results (including clinical chemistry, hematology, urinalysis, AFP, vitamins 
A, E, and 25-hydroxy vitamin D, and INR) 
Abdominal ultrasound
Discontinuations due to AEs
10.1
Adverse Events
10.1.1
Definitions and Investigator Assessments
An AE is defined as any untoward medical occurrence in an enrolled patient regardless of
causal relationship with study drug. An AE can therefore be any clinically significant 
unfavorable and unintended sign, symptom, or disease that occurs once a patient is enrolled
(ICF is signed) in the study until the patient is discharged from the study, whether or not related 
to the study drug. 
10.1.1.1
Clinical Significance
Clinical significance is defined as any abnormal finding that results in further clinical 
investigation(s), treatment(s), or the diagnosis of new condition. Patient-reported events and 
protocol-mandated laboratory values, vital signs, and physical examination findings can be 
considered clinically significant (i.e., an AE) if there is a deterioration as compared to baseline. 
Examples of clinically significant worsening from baseline could include, but is not limited to, 
events causing withdrawal from the study and events requiring medical intervention outside of 
the study causing apparent clinical manifestations, or judged relevant by the investigator.
10.1.1.2
Serious Adverse Events
Serious criteria are applied by the investigator to each AE as specifically defined below. These 
criteria are used to determine whether an AE is serious or non-serious. The assessment is made 
independently of severity assessment (Section 10.1.1.3). For example, the development of a 

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severe rash that occurs after signing of informed consent may not meet serious criteria as 
defined below and therefore would be considered a severe, non-serious AE.
Any AE that meets any 1 of the following 6 criteria is considered an SAE: 
The outcome of the AE is death
The AE is immediately life-threatening. Life-threatening means that the patient is, in the 
opinion of the investigator, at immediate risk of death from the reaction as it occurred. This 
does not include an AE that, if more severe, might have caused death
The AE results in persistent or significant disability/incapacity. Disability means a 
substantial disruption of a person's ability to conduct normal life functions
The AE requires or prolongs hospitalization
The AE results in a congenital anomaly/birth defect
The AE is an important medical event. Important medical events may meet serious 
criteria should the investigator assess that they may significantly jeopardize the patient, 
represent a significant hazard, or requires medical/surgical intervention to prevent one of
the outcomes listed above. Examples of potential SAEs based on this criterium include, 
but are not limited to, allergic bronchospasm requiring intensive treatment in an emergency 
room or at home, blood dyscrasias or convulsions even if they do not result in inpatient 
hospitalization, or the development of drug dependency and drug abuse. 
10.1.1.3
Severity Assessment
Severity assessments are based on the intensity of the event in relation to expectation. The 
investigator will assess the intensity of AEs based on the following definitions: 
Mild (awareness of sign or symptom, but easily tolerated)
Moderate (discomfort sufficient to cause interference with normal activities)
 
Severe (incapacitating, with inability to perform normal activities) 
Severity is a measure of intensity where seriousness is defined by the criteria outlined in
Section 10.1.1.2. An AE of severe intensity need not necessarily be considered serious. For 
example, nausea that persists for several hours may be considered severe nausea, but not meet 
serious criteria, and therefore would be assessed as a severe AE but not an SAE.
10.1.1.4
Causality Assessment
The investigator determines the causality of all AEs to the study drug using medical judgment 
and considering all relevant factors such as (but not limited to) the underlying study indication, 
coexisting disease, concomitant medication, relevant history, pattern of the AE, temporal 
relationship to the study drug, and de-challenge or re-challenge. The causality assessment of
the AE/SAE is to be made as follows.

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Related to study drug (possibly, probably, or definitely related)
Based on medical judgment, there is at least a reasonable possibility that the study drug caused 
the event; one or more of the following criteria apply:
The event follows a reasonable temporal sequence from administration of study drug
The event could not be reasonably attributed to the known characteristics of the patient's 
clinical state, environmental or toxic factors, or other modes of therapy administered to the 
patient
The event follows a known pattern of response to study drug
The event disappears or decreases on cessation or reduction in dose of the study drug. (It 
should be noted that in some situations an AE will not disappear or decrease in intensity 
upon discontinuation of study drug despite other clear indications of relatedness) 
The event reappears or worsens when the study drug is re-administered
Unrelated to study drug (unlikely or unrelated)
Based on medical judgment there is no reasonable possibility that the study drug caused the 
event; one or more of the following criteria apply: 
The event does not follow a reasonable temporal sequence from administration of study
drug
The event could be reasonably attributed to the known characteristics of the patient's
clinical state, concurrent illness, environment or toxic factors, or other modes of therapy 
administered to the patient
The event does not follow a known pattern of response to study drug
The event does not disappear or decrease on cessation or reduction in dose of the study
drug, and it does not reappear or worsen when the study drug is re-administered
10.1.2
Recording of Adverse Events
It is the investigator’s responsibility to assess whether each untoward event is a clinically 
significant worsening from baseline, thereby considered an AE. For all AEs, the severity, 
seriousness, and causality to study drug for each AE as outlined in Section 10.1.1 will be 
assessed and recorded in the eCRF.
All serious and non-serious AEs are collected once the caregiver/patient has signed the ICF 
and until the post-treatment follow-up (Visit 12), 28 days after the last dose of study drug. 
Any AEs or SAEs that are unresolved at the patient’s last AE assessment in the study are 
followed up by the investigator until resolution or stabilization up to the database lock and 
recorded in the eCRF. Albireo retains the right to request additional information for any patient 
with ongoing AE(s) or SAE(s) at the end of the study. 

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TEAEs that are ongoing at time of discontinuation will be followed up until week 72 by 
telephone calls every 3 months. No new AEs will be recorded after the patient has permanently 
discontinued study drug. 
TEAEs are defined as any AE that occurs after dosing (Day 1), including new AEs or the 
worsening of an event after the first dose.
If there is a clinically significant deterioration of a laboratory value/vital sign or other routine 
study assessment that is associated with a diagnosis, the clinical diagnosis will be reported as
an AE and the associated signs and symptoms will be considered additional information unless 
the sign or symptom is more severe than expected given the diagnosis. For example, if an 
investigator diagnoses a study patient with hepatitis during the study period, hepatitis would 
be considered the AE and the concomitant signs and symptoms of abdominal pain, vomiting, 
and elevated ALT and AST would not be reported separately unless, in the opinion of the 
investigator, one of these signs or symptoms is more severe than expected and therefore a 
separate AE assessment is indicated.
10.1.3
Recording and Reporting of Serious Adverse Events
Every SAE (regardless of severity and causality) that occurs once the caregiver/patient has 
signed the ICF and until the post-treatment follow-up (Visit 12), and 28 days after the final 
dose of study drug, should immediately and not later than within 24 hours of knowledge of the 
event, be reported by the investigator or delegate in the SAE Report Form. 
Report of a SAE must include at least the following information:
Patient identification information (study number, site number, initials, and date of birth [as 
per local country requirements for data protection]) 
The last study drug administration date
The  diagnosis  of  the  event  with  the  description  (or  a  brief  description  of 
signs/symptoms/clinical course if the diagnosis is not available) and the date of onset
The action used to treat the event (i.e., treatment medications, temporary discontinuation) 
The reason(s) for considering the event serious
The relationship of the event to the study drug or to the study procedure (e.g., the 
investigator's assessment of causality)
A brief narrative of the SAE
Follow-up reports including all new information obtained of the subsequent course of the SAE 
must be prepared and the information collected in the SAE Report Form submitted to ICON 
DRUG SAFETY (Pharmacovigilance and Safety Services Department) by e-mail within 
24 hours of knowledge of the event. 

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The pharmacovigilance manager (PVM) may contact the investigator to obtain further 
information on a reported SAE. The investigator/investigative staff must respond to any 
request for follow-up information or answers to questions regarding the SAE within the same 
timelines as for initial reports. 
The PVM reports the occurrence of the SAE and follow-up to the Albireo Medical Monitor for 
medical assessment of the case. 
Should an outcome of death occur within the study period or within 28 days after the last 
administration of study drug, an SAE Report Form should be completed including the main 
and contributory causes of death. 
All SAE reports must be e-mailed to the following e-mail address within 24 hours: 
ICON DRUG SAFETY (Pharmacovigilance and Safety Services Department) 
E-mail: 
 
If email is unavailable, SAEs may be transmitted via fax to the following number: 
Fax No.:
 
In a study-related medical emergency situation, when the assigned Medical Monitors for the 
study cannot be reached by a caller, an on-call physician can be reached 24 hours per day, 
7 days per week, via the ICON call center. The following number is a chargeable telephone 
number allowing a global reach from both landlines and mobile phones and the internet page 
indicated below contains a list of country-specific toll-free telephone numbers. It should be 
noted that not all countries globally have access to toll-free numbers as indicated on the 
“24/7 Medical Help desk” index. Countries without toll-free numbers need to dial the 
chargeable number as indicated below. Furthermore, toll-free numbers might not be available 
from mobile phones. 
On Call Telephone No.: 
 
https://icophone.iconplc.com 
10.1.4 
Reporting of Suspected Unexpected Serious Adverse Reactions 
Suspected unexpected serious adverse reaction (SUSAR) is an SAE that occurs in a patient, 
the nature or severity of which is not expected per the applicable product information (e.g., the 
IB for an unauthorized investigational product or summary of product characteristics for an 
authorized product). 
Reporting and tracking of SUSARs will be in accordance with all applicable competent 
authority regulations. The Ethics Committees and all investigators involved in this study will 
be informed according to national and international requirements. 
PPD
PPD
PPD

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10.2 
Laboratory Values/Vital Signs/Physical Examinations and Other Safety 
Assessments 
10.2.1 
Laboratory Assessments 
At the clinic visits indicated in Table 1, samples will be drawn for clinical chemistry, 
hematology, and urinalysis analyses. The parameters assessed are presented in Table 3. 
Blood for AFP will be drawn at Visits 1, 5, 8, and 11. Fat-soluble vitamin levels including 
vitamins A and E, and 25-hydroxy vitamin D will be assessed at Visits 1, 3, 4, 6, 7, 9, and 10 
and INR (surrogate for vitamin K) will be assessed at Visits S-2 (Cohort 2 only), 2, 3, 4, 6, 7, 
9, 10, and 12. Patients will fast (water intake only is permissible) for at least 4 hours prior to 
the collection of samples for vitamin A. Exceptions can be made for infants, <12 months of 
age, if unable to fast for the full 4 hours. If a patient has any vitamin level(s) that are outside 
of the reference range, vitamin supplementation adjustments may be required. Target ranges 
and supplementation strategy guidelines can be found in Appendix 5. 
A serum pregnancy test will be performed at Visits S-1 (Cohort 2) and Visit 1 (Cohort 1), and 
a urine pregnancy test will be collected at all other visits for girls who have reached menarche. 
If a urine pregnancy test is positive, a serum pregnancy test should be performed to confirm 
the pregnancy. Study drug administration will be held pending the confirmatory results. If the 
serum pregnancy test is negative, the patient can resume dosing. If the serum pregnancy test 
is positive, the patient should be discontinued (see Section 10.2.9). 
All samples will be processed and transported to a laboratory per instructions in the laboratory 
manual. 
The observed values will be recorded and assessed as “normal” or “abnormal not clinically 
significant” or “abnormal clinically significant”. 
For hepatic adverse events and/or hepatic decompensation, a PK sample should be collected as 
close to the onset of the event as possible (PK samples are not required during the screening 
period). 
Additional safety blood samples may be needed due to follow-up of an abnormal value or 
analysis failure. The blood samples collected for safety laboratory analysis will be destroyed 
after the analyses have been completed. 

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Table 3 
Routine Laboratory Parameters
Clinical Chemistry
Hematology
Urinalysis
Albumin
Hematocrit
Blood
ALT
Hemoglobin
Glucose
Alkaline phosphatase
Platelet count
Ketones
AST
Red blood cell count
Leukocytes
Bilirubin – total and conjugated 
Calcium
Chloride
White blood cell count and 
differential (neutrophils, 
eosinophils, basophils, 
lymphocytes, and monocytes)
Nitrites 
pH
Protein
Creatinine
Creatine kinase
GGT
Potassium
Sodium
10.2.2
Individual Patient Safety Monitoring
10.2.2.1
Liver Monitoring
Strategies to monitor markers of liver disease throughout the study are outlined below where
the ULN will be based on central laboratory reference values for age and gender.
For abnormalities classified as hepatic adverse events and/or hepatic decompensation, a PK 
sample should be collected as close to the onset of the event as possible (PK samples are not 
required during the screening period).
If isolated transaminase elevations are observed, defined as:
1. Normal bilirubin AND absence of clinical hepatitis symptoms AND
whichever comes first
U/L, whichever comes first
Then:
a) Repeat liver profile (AST, ALT, bilirubin, and prothrombin time [PT] or INR) within 
2 to 3 days 
b) Evaluate creatine phosphokinase (CPK) and lactate dehydrogenase (LDH)
c) As needed (for example, persistent ALT/total bilirubin elevation or worsening of liver 
function), consider evaluation for alternative etiologies 
Monitor the patient using close observation found in Section 10.2.2.2.

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If any ONE of the following criteria are met:
1.
 
 or absolute threshold increase of +300 U/L,
whichever comes first) AND bilirubin increases to such where total bilirubin > 2 × ULN if 
total bilirubin was within normal range at baseline
2. Transaminase elevations alone (ALT or AST >5 × ULN for patients that were normal at 
baseline) or absolute threshold of +300 U/L (for patients starting with transaminases above 
ULN at baseline) in presence of normal LDH and CPK
3. Total bilirubin increased, unrelated to hemolysis
(elevated reticulocyte count) or
established genetic diseases, such as Gilbert’s syndrome
a)
Doubling if total bilirubin was <3 mg/dL (equivalent to 51.3 µmol/L) at baseline and 
total bilirubin is greater than 2 × ULN 
b)
(equivalent to 51.3 µmol/L) at baseline
4. INR increase refractory to vitamin K administration
a)
Increase by >1.5 if INR was normal at baseline
b)
OR Increase by >0.4 if INR was abnormal at baseline
5. Any increase in total bilirubin and transaminases if accompanied by EITHER a symptom 
of clinical hepatitis (e.g., vomiting, nausea, right upper quadrant pain) OR immunological 
reaction (rash or >5% eosinophilia) 
Then:
a)
Interrupt study medication
b)
Initiate drug-induced liver injury work-up for alternative etiologies
c)
Repeat liver profile (AST, ALT, total bilirubin, direct bilirubin) and PT or INR within 
48 to 72 hours 
d)
Monitor the patient using close observation found in Section 10.2.2.2
e)
If a patient lives in a remote area, they may be tested locally and the results 
communicated to the investigator site promptly
10.2.2.2
Close Observation
Repeat liver enzyme and serum bilirubin tests two or three times weekly. Frequency 
of re-testing can decrease to once a week or less if abnormalities stabilize or the trial 
drug has been discontinued and the patient is asymptomatic 
Obtain a more detailed history of symptoms and prior or concurrent diseases
 

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Obtain a history of concomitant drug use (including non-prescription medications and 
herbal and dietary supplement preparations), alcohol use, recreational drug use, and 
special diets
Consider ruling out alternate etiology including acute viral hepatitis types A, B, C, D, 
and 
E; 
autoimmune 
or 
alcoholic 
hepatitis; 
non-alcoholic 
steatohepatitis; 
hypoxic/ischemic hepatopathy; and biliary tract disease 
Obtain a history of exposure to environmental chemical agents
Obtain additional tests to evaluate liver function, as appropriate (e.g., INR, direct 
bilirubin)
Consider gastroenterology or hepatology consultations
Follow subjects with potential drug-induced liver injury (DILI) until the laboratory, and 
new associated clinical abnormalities have normalized or returned to baseline 
(enrollment) values or have stabilized (defined as laboratory values being stable for 
3 months). Continue to work up for alternate etiologies for the abnormal liver disease 
as stated above until case has resolved. If imaging changes are found as part of the 
assessment for etiology, these should be continued to be followed until normalization 
or returned to baseline or until the investigator feels the changes have stabilized.
10.2.2.3
De-challenge/Re-challenge for Liver and Clinical Hepatitis Monitoring
1. Re-challenge is not recommended:
a) If a patient has had possible/probable drug-induced liver injury
b) If a decompensation event has occurred (i.e., variceal hemorrhage, ascites, hepatic 
encephalopathy, etc.). 
2. If the event is assessed as due to underlying cholestatic liver disease variability or another 
alternative etiology is identified AND liver tests returned to baseline, re-challenge may be 
considered after consultation with the sponsor Medical Monitor.
3. If the ALT/total bilirubin elevations are observed after re-challenge, then repeat
re-challenge is discouraged.
If a patient is permanently discontinued, monitoring should be continued as outlined in 
Section 10.2.2.8.
10.2.2.4
Diarrhea
Study drug should be discontinued if a patient develops diarrhea with at least 1 of the following 
concomitant signs or symptoms: grossly bloody stools, vomiting, dehydration requiring
°C)
and/or the diarrhea persists for 7 or more days.
should be assessed using hemoccult cards. 

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Blood in stools or any other signs of bleeding should trigger clinical and laboratory assessment 
such as measurement of PT/aPTT, INR, platelets, etc. Any deficits should be corrected, as 
clinically indicated.
Cause of bleeding should be investigated, and an evaluation should be obtained. If there is a 
reduction in hemoglobin greater than 2 g/dL there should be a discussion with the Medical 
Monitor and the appropriate work up will be decided. Information needed for this discussion 
should include presence of any diarrhea, recent iron studies, any signs of gross bleeding and 
what organs are involved, recent and current complete blood count, INR, any changes in heart 
rate, blood pressure, weight, last results of imaging and endoscopy/ colonoscopy and recent 
infectious work up, if done. 
If gross blood in stool/bleeding is seen, an AE of blood in stool/bleeding should be reported.
Study drug will be reintroduced (re-challenge) when the symptoms have resolved. If the 
diarrhea re-occurs within 1 week after the re-challenge with no alternate etiology, the patient 
will be permanently discontinued and monitored as outlined in Section 10.2.2.8.
10.2.2.5
Fat-soluble Vitamin Deficiency
Queries related to TEAEs indicative of end-organ damage, i.e., impaired hepatic synthetic 
function presenting as e.g., bone fracture/rickets, GI or other organ bleeding/ecchymosis or
night blindness, will be issued when a patient presents with worsening of fat-soluble vitamin 
deficiency (see Section 10.2.1 for monitoring fat-soluble vitamin levels by laboratory 
assessments). Treatment should be discontinued in patients with evidence of end-organ damage 
due to fat-soluble vitamin deficiency.
10.2.2.6
Treatment-emergent Iron Deficiency Anemia
Events of iron deficiency anemia are identified as part of TEAE reporting and hematology 
assessments. Patients will be evaluated for fecal blood loss if they present with:
A decrease
 2 g/dL
A report of blood in stool; if so, a further diagnostic work up will be performed, 
following confirmation of blood in stool with hemoccult cards. 
Patients will be managed per institutional standard of care with iron supplementation.
10.2.2.7
Re-challenge after Discontinuation/Interruption of Study Drug
The DSMB will evaluate the safety data for patients who have discontinued study drug for an 
extended period on a case-by-case basis to determine whether re-challenge with A4250 is 
appropriate. The minimal duration of the discontinuation should be at least one to two weeks.
Patients that have discontinued for an extended period and allowed re-challenge by DSMB will 
use the last labs prior to restart as the new baseline for determining if DILI criteria are met.

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10.2.2.8 
Monitoring after Permanent Discontinuation of Study Drug Due to Safety 
Once study drug is permanently discontinued for liver, hepatitis, diarrhea, or other severe AE 
related to study drug, the patient will be monitored weekly until the laboratory and clinical 
parameters have normalized/stabilized. 
10.2.3 
Demographics/Medical and Surgical History (For Cohort 2 only) 
Demographic information per country regulations, along with medical and surgical history, 
will be obtained and recorded in the eCRF at Visit S-1. 
Medical and surgical history will be entered in the eCRF at Visit S-1. This includes date of 
diagnosis of PFIC, prior investigational medications for PFIC, historical (3 months prior to 
Screening, and up to 5 years prior to Screening for BRIC) hepatic biochemical parameters (e.g., 
AST, ALT, and total bilirubin), ongoing medication, any surgery performed, any other 
diagnosis, and historical biopsy data. 
For patients with BRIC, information on flares will be collected, including frequency, duration, 
and severity of flares within the last 6 months at a minimum, and within the last 5 years, if 
possible. A flare/cholestatic episode can be self-reported or clinically assessed based on 
medical history. Clinical signs and symptoms during a cholestatic episode/flare can include 
nausea, vomiting and pruritus followed by jaundice, fatigue, weight loss, malaise, steatorrhoa, 
night blindness. Increased bilirubin and alkaline phosphatase levels and increased INR can be 
observed. ALT, AST and GGT can be normal to mildly elevated. 
If a liver biopsy has been performed within 1 year prior to Screening, or during the study, the 
results will be recorded in the eCRF. 
10.2.4 
Clinical Genetic Testing (For Cohort 2 only) 
For previous confirmatory clinical genetic testing results for PFIC, including BRIC, Type 
performed prior to Screening Visit S-1, the confirmatory clinical genetic testing laboratory 
report will be verified to determine eligibility. 
If the historical clinical genetic result is equivocal, unavailable, or unobtainable, clinical 
genetic analysis will be performed to confirm pathologic biallelic variations of the ATP8B1, 
ABCB11 ABCB4, NR1H4, TJP2, DCDC2, CLDN1, and MYO5B genes and verified to 
determine eligibility. No other diagnostic genetic testing will be offered. 
10.2.5 
Physical Examination 
A physician or suitably trained qualified assistant will perform a complete physical 
examination, including a skin examination, at Visits S-1, 1, 3, 5, 8, and 11. 
A complete physical examination will include assessment of general appearance, eyes, ears, 
nose, throat, head/neck/thyroid, lymph nodes, cardiovascular, lungs/chest, abdomen, 
genitourinary, extremities, skin, musculoskeletal, neurologic, and other.  An abbreviated 

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physical examination will include general appearance, cardiovascular, abdomen, and other 
assessments based on patient status. 
Skin will be thoroughly examined and excoriations/scratch marks recorded. 
10.2.6 
Vital Signs 
Evaluation of vital signs will be performed at all visits. This includes blood pressure (systolic 
and diastolic), pulse, respiratory rate, temperature, height/length (using certified stadiometer), 
mid-arm circumference (3 repeat measures), and body weight (using a certified weight scale) 
at clinic visits. BMI will be calculated. 
10.2.7 
Abdominal ultrasound 
Ultrasound of the liver and spleen will be performed at Visits 1, 5, 8, and 11. Liver size, 
echogenicity, and presence of masses/nodules as well as spleen size will be recorded. 
10.2.8 
Overdose 
A4250 is minimally absorbed and has a very low systemic availability. Based on toxicology 
data, for study purposes any dose exceeding a total of >3 mg/kg body weight of A4250 taken 
as a single dose or as a cumulative dose within 24 hours is defined as an overdose. 
The no-adverse-effect dose level in the most sensitive species (defined as 20 mg/kg/day) in the 
rat 1 month toxicity study gives a human equivalent dose of approximately 194 mg/day in a 
60 kg person. This dose is approximately 10-fold higher than the maximum possible dose 
predicted in human studies (20 mg). 
The investigator/investigative staff should immediately, and not later than within 24 hours of 
knowledge, report an overdose in the SAE Report Form. In the event of an A4250 overdose, 
the patient should be monitored closely. 
10.2.9 
Pregnancy 
If a pregnancy is discovered in a female patient enrolled in the study before the end of dosing 
the patient will be immediately discontinued from the study and will attend the same visits as 
a prematurely withdrawn patient. If the pregnancy is discovered after the end of dosing the 
patient will continue in the study per protocol. If a pregnancy occurs in a male patient’s partner 
at any time during the study, the pregnancy should also be reported and followed. 
Pregnancy is not considered to be an AE. However, if the patient has been dosed with the study 
drug, the pregnancy must be reported on the Paper Pregnancy Notification Form immediately 
within 24 hours after recognition to Pharmacovigilance Manager and Pharmacovigilance and 
Safety Services Department (please refer to Section 10.1.3). Date of exposure and as far as 
possible, details of the period of gestation at the time of exposure must be given. 
The pregnancy should be followed up to determine outcome, including spontaneous 
termination, details of birth, and presence of any birth defects, congenital anomalies or 

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newborn or maternal complication. An infant who was exposed in-utero will be followed for 
up to 2 years after delivery. Individual cases with an abnormal outcome in association with 
the study drug should be reported on an expedited basis, i.e., reported rapidly to a competent 
authority. 

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11 
STATISTICAL EVALUATION 
11.1 
Sample Size and Power 
There is no formal hypothesis testing in this open label study. Sample size for Cohort 1 was 
determined in Study A4250-005. For Cohort 1, patients will be enrolled following completion 
or participation of 12 weeks of Study A4250-005. The expected proportion of patients with at 
least one event, i.e., surgical bile diversion or liver transplantation or death, in untreated 
patients is expected to be high enough to be able to detect an improvement after A4250 
treatment. For the other endpoints, mainly descriptive analyses will be performed. 
The proportion of patients with at least one event (i.e., surgical bile diversion or liver 
transplantation or death), that can be expected in a non-treated population depends on PFIC 
type and age distribution of the included patients. The expected proportion of patients with 
events will be calculated for the study population once each patient’s age and PFIC type are 
known, using the probability that a patient will get an event estimated from the reference 
population in the ongoing observational cohort study, NAtural Course and Prognosis of PFIC 
and Effect of Biliary Diversion (NAPPED). 
As an example, if the expected proportion with at least one event is estimated to be 30% in the 
study population, and then if the proportion of patients with at least one event during A4250 
long-term treatment are shown to be only 10% in the study, the power is approximately 89% 
to 96% (1-sided test, alpha=2.5%) for a confidence interval (CI) with upper boundary <30% 
based on a sample size of n=48 to 60. The sample size of 60 patients for Cohort 2 was estimated 
based on the availability of target patient population to evaluate the therapeutic benefit for those 
patients. 
11.2 
Statistical Methods 
11.2.1 
Statistical Analysis Sets 
Full Analysis Set 
The full analysis set (FAS) will consist of all patients who received at least 1 dose of study 
drug in Study A4250-008. The FAS will be the primary analysis set for all analyses unless 
otherwise specified. 
11.2.2 
Methods of Statistical Analyses 
11.2.2.1 
General Principles 
Descriptive statistics will mainly be used in this open-label extension study. Patients with BRIC 
will be presented separately in efficacy assessments. All statistical analyses will be performed 
using SAS version 9.3 or higher. 
Baseline 1 will be defined as the last value prior to treatment start in Study A4250-005 for 
Cohort 1 patients. 

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Baseline 2 will be defined as the last value prior to treatment start in Study A4250-008 for all 
patients. Baseline 2 will be used in all analyses unless otherwise specified.
Descriptive statistics will be summarized for Cohort 1, Cohort 2 excluding BRIC, Cohort 2 
BRIC, and combined Cohort 1 + Cohort 2 excluding BRIC. Within Cohort 1, the following 
subgroups will be presented: ‘A4250 40 µg/kg/day (-005) to 120 µg/kg/day (-008)’, ‘A4250
120 µg/kg/day (-005) to 120 µg/kg/day (-008)’, ‘A4250 40 µg/kg/day (-005) and 120 µg/kg/day
(-005) to 120 µg/kg/day (-008)’, and ‘placebo (-005) to 120 µg/kg/day (-008)’. Within Cohort
2 excluding BRIC, 3 subgoups (‘40 µg/kg/day’, ‘40 µg/kg/day to 120 µg/kg/day’, and
‘120 µg/kg/day’) will be presented. Cohort 1 Placebo to A4250 120 µg/kg/day will also be 
combined with Cohort 2 excluding BRIC for presentations. 
11.2.2.2
Missing Data
Missing data will be reported descriptively. In general, imputations of missing observations 
will not be made. Any additional sensitivity analysis concerning missingness and details 
regarding handling of missing data will be described in the statistical analysis plan (SAP).
Continued collection of efficacy data for patients who discontinue treatment will be made as 
far as possible.
11.2.2.3
Demographic and Baseline Characteristics
For Cohort 1, descriptive summaries of demographics and other baseline characteristics 
(including medical and surgical history) will be presented overall using the FAS. For Cohort 2, 
descriptive summaries of demographics and other baseline characteristics will be presented 
overall for the full analysis set as well as by the underlying diagnostics subgroups. 
Prior medication will be summarized overall using the full analysis set.
11.2.2.4
Subject Disposition
The following will be summarized overall by Cohort:
Patients enrolled (who signed the informed consent)
Patients treated
Patients completing treatment
Patients discontinuing treatment and reason 
Patients completing the study
Patients withdrawing early (including withdrawal reason)
Additionally, patients enrolled, included in the FAS will be summarized by region by Cohort.

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11.2.2.5
Evaluation of Primary Efficacy Variables
The proportion of positive pruritus assessments at the patient level over the 72-week 
treatment period will be summarized. A positive pruritus assessment is defined as a 
-point drop from baseline on the Albireo ObsRO 
instrument. At each assessment, the AM score will be compared to the baseline AM average, 
and the PM score will be compared to the baseline PM average. Both AM and PM pruritus 
assessments will be included in the analysis of this endpoint. Baseline will be defined as the 
average score from 14 days prior to treatment start in Study A4250-008 for AM and PM, 
respectively.
Fasting serum bile acids baseline will be calculated as the average of the pre-dose value in 
Study A4250-008 (Visit 1) and the previous visit (Visit 8 in study A4250-005) for Cohort 1. 
Fasting serum bile acids baseline will be calculated as the average of Visit S-2 and the pre- 
dose Visit 1 values in Study A4250-008 for Cohort 2. The end value is the average of the 
values at Weeks 70 and 72 in study A4250-008. 
The change from baseline over the Treatment Period in serum bile acids will be analyzed 
mainly by using descriptive statistics. Change over time will also be displayed using 
graphical presentations (e.g., a spaghetti plot which illustrates the change in both Study 
A4250-005 and Study A4250-008 by treatment group in Study A4250-005). In addition, 
change from baseline 1 to end of treatment will be analyzed by using one-sample T-test or 
Wilcoxon signed-rank test as appropriate.
As an exploratory analysis of pruritus and serum bile acids, a comparison of treatment with 
A4250 120 µg/kg/day during the first 24 weeks of Study 008 vs placebo patients over the 24- 
week treatment period from Study 005 will be carried out. 
11.2.2.6
Evaluation of Secondary and Exploratory Efficacy Variables
All secondary and exploratory variables listed under Sections 9.1.2 and 9.1.3 will be analyzed 
descriptively for categorical and continuous data, as applicable. For continuous data, the
change from baseline will be analyzed in addition to the actual visit values. For categorical 
data, shift tables or frequency and percentages of patients will be presented as appropriate.
Change in growth (Z-score, SD from P50 standard growth curve) will be analyzed by using
one-sample T-test or Wilcoxon signed-rank test as appropriate.
Change in growth
(height/length for age, weight for age, BMI, and mid-arm circumference) will also be displayed 
using graphical presentations.
A 95% CI will be calculated for the proportion of patients experiencing surgical bile diversion 
or liver transplantation or death as well as for the proportion of patients experiencing surgical 
bile diversion or death or liver transplantation. The upper boundary will be compared to the 
expected proportion of events, using the event probability estimated from the untreated
reference population in an ongoing observational cohort study. 

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Time to first event, i.e., time to surgical bile diversion or liver transplantation or death, will be 
explored by descriptive statistics and Kaplan-Meier curves, which also will be used to make a 
comparison to the NAPPED population. The propensity score matched cohort analysis using 
inverse probability of treatment weights will be used to match the study patient population to
the reference population based on age group and PFIC type. 
11.2.2.7
Evaluation of Safety Variables
Safety data will be analyzed using descriptive statistics and summaries overall of SAEs, AEs, 
vital signs, clinical laboratory tests (hematology, clinical chemistry and urinalysis) and 
concomitant medication. Analyses will be performed using the full analysis set.
Summaries of AEs (coded according to the Medical Dictionary for Regulatory Activities 
(MedDRA) system organ class and MedDRA preferred term) will include: 
Overview of the incidence of TEAEs (TEAEs, Drug-related TEAEs, TEAEs leading to 
study discontinuation, and Treatment-emergent SAEs)
TEAEs by system organ class (SOC) and preferred term
 
Intensity of TEAEs by SOC and preferred term 
Drug-related TEAEs by SOC and preferred term
TEAEs leading to study discontinuation by SOC and preferred term 
Treatment-emergent SAEs by SOC and preferred term
Concomitant medication use during the Treatment Period will be summarized by Anatomical 
Therapeutic Chemical (ATC) class and World Health Organization (WHO) preferred name.
Summaries of vital signs will be presented. For each visit, the actual results and the change 
from baseline, and the number and percentage of patients with potentially clinically significant 
(PCS) values observed post-baseline will be presented.
Summaries of clinical safety laboratory data will be presented. For each visit, the actual result 
and the change from baseline, and the number and percentage of patients with PCS values 
observed post-baseline will be presented.
Data listings will be provided for each patient for all safety parameters.
11.2.2.8
Compliance and Exposure
Exposure will be analyzed by calculating the number of days with exposure to study drug. For 
Cohort 2 patients who dose escalate from 40 µg/kg/day to 120 µg/kg/day, exposure in each
dose and overall will be calculated. Results will be presented overall using the full analysis 
set.
The percentage compliance will be described overall, and the number of patients with a 

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A summary of patients who down-titrated from 120 µg/kg/day to 40 µg/kg/day during the study 
will be presented as well. 
11.2.3 
Interim Analysis 
Analyses may be performed at select time points throughout the collection of patient data for 
regulatory requirements and sponsor decision making purposes. 
11.2.4 
Data Safety Monitoring Board 
A DSMB consisting of sponsor-independent clinical experts and sponsor-independent 
statistical expert(s) will be established for Study A4250-005, and continue for this study. The 
DSMB will periodically (approximately on a quarterly basis) meet for the review of 
accumulating study data, including safety (AE and laboratory data), and liver values. 
The DSMB will make recommendations for the remaining part of the study (further details will 
be provided in the DSMB charter). The DSMB may recommend continuing with the study as 
planned or stopping the study early for safety reasons. The DSMB will submit its 
recommendations in writing to Albireo Medical/ICON who are responsible for responding to 
the recommendations of the DSMB and taking appropriate action. The investigators will only 
be informed by Albireo Medical/ICON if the study requires a protocol amendment or is 
stopped. The DSMB may choose to make additional evaluations at any time if they feel this is 
warranted from a safety point of view. 
The DSMB will act according to its own written standard operating procedure described in a 
charter and will prepare written minutes of its meetings. The charter of the DSMB will be 
stored in the Trial Master File. The DSMB will maintain records of its meetings and these will 
become part of the study file when the study is complete. 

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12 
DIRECT ACCESS TO SOURCE DATA/NOTES 
The investigator/institution shall provide direct access to source data/documents for 
study-related monitoring, audits, IEC/IRB review and regulatory inspection. 

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13 
QUALITY CONTROL AND QUALITY ASSURANCE 
13.1 
Conduct of the Study 
Albireo/ICON shall implement and maintain quality control and quality assurance procedures 
with written standard operating procedures to ensure that the study is conducted and data are 
generated, documented, and reported in compliance with the protocol, Good Clinical Practice 
(GCP) and applicable regulatory requirements. 
This study shall be conducted in accordance with the provisions of the Declaration of Helsinki 
(October 1996) and all revisions thereof, and in accordance with US FDA regulations (Code 
of Federal Regulations, Sections 312.50 and 312.56) and with International Council for 
Harmonisation (ICH) GCP (EMA/CHMP/ICH/135/1995), as applicable. 
The investigator may not deviate from the protocol without a formal protocol amendment 
having been established and approved by the competent authority, as applicable, and IEC/IRB 
approval, except when necessary to eliminate immediate hazards to the patient or when the 
change(s) involve(s) only logistical or administrative aspects of the study. Any deviations may 
result in the patient having to be withdrawn from the study and render that patient 
non-evaluable. 
13.2 
Study Monitoring 
Before study initiation, at a site initiation visit or at an investigator’s meeting, an Albireo 
representative or designee will review the protocol and eCRF with the investigators and the 
investigative staff. During the study, the clinical monitor (clinical research associate [CRA]) 
will visit the site regularly to check the completeness of patient records, the accuracy of entries 
on the eCRFs, the adherence to the protocol and to GCP, the progress of enrollment, and to 
ensure that study drug is being stored, dispensed, and accounted for according to specifications. 
The investigator must ensure that eCRFs are completed within a timely period of the patient 
visits, as per individual site agreements, and must allow the CRA and Albireo representative 
or designee periodic access to patient records and all study-related materials, including relevant 
hospital or clinical records, to confirm their consistency with the eCRF entries. No information 
in these records about the identity of the patients will leave the study center. Albireo 
monitoring standards require full verification for the presence of the signed ICF, adherence to 
the inclusion/exclusion criteria, documentation of SAEs, and recording of primary efficacy and 
safety variables. The CRA will review source data compared with the eCRFs and will verify 
source data according to the study-specific monitoring plan. The design of the study, the 
frequency of patient visits, and the site enrollment rate will determine the frequency of 
monitoring visits. Upon study completion, the CRA will visit the site to conduct a study 
termination visit, which will include collection of any outstanding documentation. 

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Remote monitoring practices may be employed in accordance with the country/institution 
specific guidelines in circumstances where an on-site monitoring visit is not feasible (i.e., 
COVID-19). 
It is recommended that the investigator/investigative staff log into the eCRF system every 
working day or at minimum twice weekly in order to provide a prompt response to queries. 
The investigator/investigative staff should respond to queries and make any relevant changes 
to the study data within 3 working days. 

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14 
ETHICS 
14.1 
Independent Ethics Committee/Institutional Review Board 
Prior to the start of the study, the investigator is responsible for ensuring that the protocol and 
informed consent form (ICF) have been reviewed and approved by the applicable IEC/IRB and 
competent authority. The IEC/IRB shall be appropriately constituted and perform its functions 
in accordance with US FDA, ICH GCP and/or local requirements, as applicable. 
The IEC/IRB and regulatory authority (competent authority), as applicable, shall approve all 
protocol amendments (except for logistical or administrative changes), written informed 
consent 
documents 
and 
document 
updates, 
patient 
recruitment 
procedures 
(e.g., 
advertisements), written information to be provided to the patients, IB, available safety 
information, information about payment and compensation available to patients and caregivers, 
the investigator's curriculum vitae and/or other evidence of qualifications and any other 
documents requested by the IEC/IRB or competent authority. 
14.2 
Written Informed Consents and Assents 
The investigator (physician) or investigative staff, as according to local regulation, will explain 
to each patient (or legally authorized representative) the nature of the study, its purpose, the 
procedures involved, the expected duration, alternative treatment, the potential risks and 
benefits involved, and any discomfort that may occur. Each caregiver/patient will be informed 
that participation in the study is voluntary and that he/she or their child may withdraw from the 
study at any time and that withdrawal of consent will not affect his/her subsequent medical 
treatment or relationship with the treating physician. 
Caregivers/patients will be informed that they/their children may experience side-effects or be 
at risk for symptoms, illnesses, or complications that cannot be foreseen by Albireo. As with 
other medications, people treated with A4250 may be at risk of developing allergic reactions 
or anaphylaxis. Caregivers/patients will be advised that study procedures include regular blood 
sampling for measurement of safety parameters and biological markers and that some minor 
risks are associated with these procedures. 
This informed consent should be given by means of a signed ICF, written in non-technical 
language in accordance with applicable GCP, the Declaration of Helsinki, and regulatory 
authorities. The caregiver(s)/patient should read and consider the statements before signing 
and dating them and should be given a copy of each signed document. If written consent is not 
possible, oral consent can be obtained if witnessed and followed by a signed statement from 
one or more persons not involved in the study, indicating why the patient was unable to sign 
the form. No patient can enter the study before his/her or caregiver(s), as required by country 
regulation, informed consent has been obtained. 
The ICF must be submitted by the investigator/investigative staff with the protocol to the 
applicable IEC/IRB for review and approval. Albireo will supply an ICF which complies with 

A4250 – IND 130591 
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Amendment 6.2 Sweden, 11 February 2022 
81 
 
 
 
regulatory requirements and country laws and is considered appropriate for the study. Any 
changes to the ICF suggested by the investigator must be agreed to by Albireo before 
submission to the IEC and a copy of the approved version must be provided to the clinical 
monitor after IEC approval. 

A4250 – IND 130591 
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Amendment 6.2 Sweden, 11 February 2022 
82 
 
 
 
15 
DATA HANDLING AND RECORD KEEPING 
15.1 
Case Report Forms/Source Data Handling 
The investigator shall be provided with standardized eCRFs and shall ensure that all data from 
patient visits are promptly entered into the eCRFs in accordance with the specific instructions 
given. The investigator must sign each completed eCRF, verifying the accuracy and integrity 
of the data recorded. 
A list of the normal ranges for all laboratory tests to be undertaken forms part of the 
documentation to be collated prior to study start. As a central laboratory has been selected to 
conduct any or all tests, it is essential that all samples be analyzed at the central laboratory. 
The investigator must maintain source documents such as laboratory reports, consultation 
reports, and complete medical history and physical examination reports. 
As no ethnicity data can be collected in the source document for study sites in France, the eCRF 
will be the Source Document for “origines ethniques”. 
15.2 
Retention of Essential Documents 
Essential documents, as defined by ICH GCP, include: the signed protocol and any 
amendment(s); copies of the completed eCRFs (for site archiving, compact discs of eCRF data 
for participating patients will be provided); signed ICFs; hospital records and other source 
documents; IEC/IRB approvals, including the associated documents, and all related 
correspondence; drug accountability records; study correspondence; and a list of patients’ 
names and addresses. 
The investigator/investigative staff must retain copies of these essential documents for the 
minimal period specified by ICH GCP and/or by applicable regulatory requirements 
(whichever is longer). The investigator/investigative staff will inform Albireo of the location 
where the essential documents are stored and must contact Albireo for approval before 
disposing of any essential documents. The investigator/investigative staff should take 
measures to prevent accidental or premature destruction of these documents. 

A4250 – IND 130591 
EudraCT 2017-002325-38 
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M5.3.5.1 – Protocol A4250-008 
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Amendment 6.2 Sweden, 11 February 2022 
83 
 
 
 
16 
FINANCING AND INSURANCE 
Financing and insurance are addressed in a separate agreement. 

A4250 – IND 130591 
EudraCT 2017-002325-38 
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Amendment 6.2 Sweden, 11 February 2022 
84 
 
 
 
17 
PUBLICATION POLICY 
Albireo will retain the ownership of all data. When the study is complete, Albireo shall arrange 
the analysis, tabulation of data and preparation of a clinical study report. Albireo may also use 
the data for publication, presentation at scientific meetings and submission to regulatory 
authorities. All proposed publications based on this study must be subject to the sponsor’s 
approval requirements. 

A4250 – IND 130591 
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Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
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Amendment 6.2 Sweden, 11 February 2022
85
18
REFERENCE LIST
1. A4250 Investigator’s Brochure.
2. Alissa FT, Jaffe R, Shneider BL. Update on progressive familial intrahepatic cholestasis. J 
Pediatr Gastroenterol Nutr. 2008;46(3):241-52. 
3. Bull LN, Thompson RJ. Progressive Familial Intrahepatic Cholestasis. Clin Liver Dis. 2018 
Nov;22(4):657-669.
4. Davit-Spraul A, Gonzales E, Baussan C, et al. Progressive familial intrahepatic cholestasis. 
Orphanet J Rare Disease 2009;4:1-12. 
5. Gomez-Ospina N, Potter CJ, Xiao R, et al. Mutations in the nuclear bile acid receptor FXR 
cause progressive familial intrahepatic cholestasis. Nat Commun. 2016 Feb 18;7:10713. 
6. Hofmann AF. The enterohepatic circulation of bile acids in mammals: form and functions. 
Front Biosci (Landmark Ed). 2009 Jan 1;14:2584-98. 
7. Hori T, Justin H, Nguyen JH and Uemoto S. Progressive familial intrahepatic cholestasis. 
Hepatobiliary pancreat Dis Int. 2010; 9(6):570-8. 
8. Jacquemin E. Progressive familial intrahepatic cholestasis. Genetic basis and treatment.
Clin Liver Dis. 2000 Nov;4(4):753-63. 
9. Miethke AG, Zhang W, Simmons J, et al. Pharmacological inhibition of ASBT changes 
bile composition and blocks progression of sclerosing cholangitis in mdr2 knockout mice. 
Hepatology. 2016 February; 63(2):512–23.
10. Murray CS, Rees JL. Are subjective accounts of itch to be relied on? The lack of relation 
between visual analogue itch scores and actigraphic measures of scratch. Acta Derm 
Venereol. 2011;91(1):18-23. 
11. Pawlikowska L, Strautnieks S, Jankowska I. et al. Differences in presentation and 
progression between severe FIC1 and BSEP deficiencies, J Hepatol. 2010; 53(1):170-8. 
12. Shneider BL, Magee JC, Bezerra JA, et al. Efficacy of fat-soluble vitamin supplementation 
in infants with biliary atresia. Pediatrics, 2012;130(3):e607-14. 
13. Stapelbroek JM, van Erpecum KJ, Klomp LW, Houwen RH. Liver disease associated with 
canalicular transport defects: current and future therapies. J Hepatol. 2010 Feb;52(2):258- 
71.
14.
Mechanisms  to  Clinical  Implications.  Can  J  Gastroenterol  Hepatol.  2018  Jul 
26;2018:2313675.
15. Strubbe B, Geerts A, Van Vlierberghe H, Colle I. Progressive familial intrahepatic 
cholestasis and benign recurrent intrahepatic cholestasis: a review. Acta Gastroenterol 
Belg. 2012 Dec;75(4):405-10. 

A4250 – IND 130591 
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Amendment 6.2 Sweden, 11 February 2022 
86 
 
 
 
16. Suchy FJ. “Approach to the Infant With Cholestasis.” Liver Disease in Children. Ed. 
Frederick J. Suchy. New York: Cambridge University Press; 2007 179-189. Print. 
17. Venkat VL, Shneider BL, Magee JC, et al. Total Serum Bilirubin Predicts Fat-Soluble 
Vitamin Deficiency Better Than Serum Bile Acids in Infants with Biliary Atresia. J Pediatr 
Gastroenterol Nutr. 2014;59(6):702-7. 
18. Vitale G, Gitto S, Vukotic R, et al. Familial intrahepatic cholestasis: New and wide 
perspectives. Dig Liver Dis. 2019 Jul;51(7):922-33. 
19. Whitington PF, Whitington GL. Partial external diversion of bile for the treatment of 
intractable 
pruritus 
associated 
with 
intrahepatic 
cholestasis. 
Gastroenterology. 
1988;95(1):130-6. 

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Amendment 6.2 Sweden, 11 February 2022 
87 
 
 
 
19 
APPENDICES 
Appendix 1 
Concomitant Medication Guidelines 

 
A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
 
 
Appendix 2 
Diary Questions including Albireo Patient-Reported 
Outcomes/Observer-Reported Outcome Instrument 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confidential 
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Amendment 6.2 Sweden, 11 February 2022 

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Amendment 6.2 Sweden, 11 February 2022 
Page 1 of 2 
 
 
Appendix 2: Diary Questions including Albireo Patient-Reported 
Outcomes/Observer-Reported Outcome Instrument 
Patient-Reported Outcome 
 
Morning Diary (to be completed shortly after waking each morning) 
Please answer the questions on the following screens. There are no right or wrong answers. Please 
think about the time since you went to bed last night (beginning when you started trying to fall 
asleep). 
1. How bad was your worst itching since you 
went to bed last night? 
 
2. How hard was it to fall asleep last night 
because of your itching? 
 
3. How hard was it to stay asleep last night 
because of your itching? 
 
4.  Did you wake up last night because of 
itching? 
No / Yes 
5.  How tired do you feel this morning? 
 
 
 
Bedtime Diary (to be completed when going to bed each night) 
Please answer the questions on the following screens. There are no right or wrong answers. Please 
think about the time since you woke up this morning. 
1. How bad was your worst itching since you 
woke up this morning? 
 
2. How tired were you since you woke up this 
morning? 
 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.2 Sweden, 11 February 2022 
Page 2 of 2 
 
 
 
Observer Reported Outcome 
 
Morning Diary (to be completed shortly after child wakes up each morning) 
Please answer the questions on the following screens. There are no right or wrong answers. Please 
think about the time since your child went to bed last night (beginning when your child started trying 
to fall asleep). As a reminder, when we use the term “scratching,” we would like you to think about all 
of the different types of scratching behaviors that you can see. 
1. How bad was your child’s worst scratching 
since he/she went to bed last night? 
 
2.  Since your child went to bed last night, did 
you see blood due to scratching? 
No / Yes 
3. Did your child need a caregiver to help 
him/her fall asleep last night due to his/her 
itching? 
No / Yes 
4. Did your child need a caregiver to soothe 
him/her at some time during the night last 
night due to his/her itching? 
No / Yes 
5.  Did your child need a caregiver to sleep 
with him/her at some time during the night 
last night due to his/her itching? 
No / Yes 
6. How many times did you notice that your 
child woke up last night? 
0-99 
7. Did your child take any prescribed or over- 
the-counter medicines before going to bed 
last night that may have made him/her 
sleepy? 
No / Yes 
 
 
Bedtime Diary (to be completed when child is going to bed each night) 
Please answer the questions on the following screens. There are no right or wrong answers. Please 
think about the time since your child woke up this morning. As a reminder, when we use the term 
“scratching,” we would like you to think about all of the different types of scratching behaviors that 
you can see. 
1. How bad was your child’s worst scratching 
since he/she woke up this morning? 
 
2.  How tired did your child seem to be today? 
 

 
A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
 
 
Appendix 3 
Patient Global Impression of Change (PGIC) and Patient Global 
Impression of Symptoms (PGIS) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confidential 
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M5.3.5.1 – Protocol A4250-008
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Amendment 6.2 Sweden, 11 February 2022
Page 1 of 4
Appendix 3: Patient Global Impression of Change (PGIC) and Patient Global 
Impression of Symptoms (PGIS)
ITCH
PGIC – CHILD
Please pick the answer below that best describes the overall change in your itch since you started 
taking the study medicine.
Very much better 
Much better
A little better 
No change
A little worse 
Much worse
Very much worse
PGIC – PARENT
Please choose the response below that best describes the overall change in your child’s
scratching since he/she started taking the study medication.
Very much better 
Moderately better 
A little better
No change
A little worse
Moderately worse 
Very much worse
PGIC – CLINICIAN
Please choose the response below that best describes the overall change in your patient’s 
scratching since he/she started taking the study medication.
Very much better 
Moderately better 
A little better
No change
A little worse
Moderately worse 
Very much worse

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
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Amendment 6.2 Sweden, 11 February 2022
Page 2 of 4
PGIS – CHILD
Please choose the answer below that best describes how bad your itch has been the past week.
None
A little
Medium 
Bad
Very Bad
PGIS – PARENT
Please choose the response below that best describes the severity of your child’s scratching over 
the past week.
None 
Mild
Moderate 
Severe
Very Severe
PGIS – CLINICIAN
Please choose the response below that best describes the severity of your patient’s scratching 
over the past week.
None 
Mild
Moderate 
Severe
Very Severe

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Confidential
Amendment 6.2 Sweden, 11 February 2022
Page 3 of 4
SLEEP
PGIC – CHILD
Please choose the answer below that best describes the overall change in your sleep problems 
since you started taking the study medicine.
Very much better 
Much better
A little better 
No change
A little worse 
Much worse
Very much worse
PGIC – PARENT
Please choose the response below that best describes the overall change in your child’s sleep
problems since he/she started taking the study medication.
Very much better 
Moderately better 
A little better
No change
A little worse
Moderately worse 
Very much worse
PGIC – CLINICIAN
Please choose the response below that best describes the overall change in your patient’s sleep 
problems since he/she started taking the study medication.
Very much better 
Moderately better 
A little better
No change
A little worse
Moderately worse 
Very much worse
PGIS – CHILD
Please choose the answer below that best describes how bad your sleep problems have been 
over the past week.
None
A little
Medium 
Bad

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
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Amendment 6.2 Sweden, 11 February 2022
Page 4 of 4
Very Bad
PGIS – PARENT
Please choose the response below that best describes the severity of your child’s sleep problems 
over the past week.
None 
Mild
Moderate 
Severe
Very Severe
PGIS – CLINICIAN
Please choose the response below that best describes the severity of your patient’s sleep 
problems over the past week.
None 
Mild
Moderate 
Severe
Very Severe

 
A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
 
 
Appendix 4 
Pediatric Quality of Life Inventory (PedQL) Questionnaire 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confidential 
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Amendment 6.2 Sweden, 11 February 2022 

01/00
PedsQL-4.0-Core-PT - United States/English
Original version
PedsQL-4.0-Core-PT_AU4.0_eng-USori
DIRECTIONS
On the following page is a list of things that might be a problem for your child. 
Please tell us how much of a problem each one has been for your child 
during the past ONE month by circling:
0 if it is never a problem
1 if it is almost never a problem
2 if it is sometimes a problem
3 if it is often a problem
4 if it is almost always a problem
There are no right or wrong answers.
If you do not understand a question, please ask for help.
PedsQL
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee
IInnvveennttoorryy
Version 4.0
PARENT REPORT for TODDLERS (ages 2-4) 
PedsQL 4.0 - Parent (2-4)
Not to be reproduced without permission
Copyright © 1998 JW Varni, Ph.D. All rights reserved
ID# 
Date:

 
 
 
How much of a problem is this for you? 
 
 
Not at all 
Sometimes 
A lot 
© 
© 
® 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
PedsQL 4.0 - (5-7) 
01/00 
Not to be reproduced without permission 
Copyright© 1998 JW Varni, Ph.D. All rights reserved. 
PedsQL-4.0-Core - United States/English - Original version 
PedsQL-4.0-Core-YC_AU4.0_eng-USori 

PedsQL 4.0 - Parent (5-7) 
01/00
Not to be reproduced without permission
Copyright © 1998 JW Varni, Ph.D. All rights reserved
PedsQL-4.0-Core-PYC
United States/English
Original version
PedsQL-4.0-Core-PYC_AU4.0_eng-USori
DIRECTIONS
On the following page is a list of things that might be a problem for your child. 
Please tell us how much of a problem each one has been for your child 
during the past ONE month by circling:
0 if it is never a problem
1 if it is almost never a problem
2 if it is sometimes a problem
3 if it is often a problem
4 if it is almost always a problem
There are no right or wrong answers.
If you do not understand a question, please ask for help.
PedsQL
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee
IInnvveennttoorryy
Version 4.0
PARENT REPORT for YOUNG CHILDREN (ages 5-7) 
ID# 
Date:

PedsQL 4.0 - (8-12) 
01/00
Not to be reproduced without permission
Copyright © 1998 JW Varni, Ph.D. All rights reserved
PedsQL-4.0-Core-C
United States/English
Original version
PedsQL-4.0-Core-C_AU4.0_eng-USori
DIRECTIONS
On the following page is a list of things that might be a problem for you. 
Please tell us how much of a problem each one has been for you 
during the past ONE month by circling:
0 if it is never a problem
1 if it is almost never a problem
2 if it is sometimes a problem
3 if it is often a problem
4 if it is almost always a problem
There are no right or wrong answers.
If you do not understand a question, please ask for help.
PedsQL
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee
IInnvveennttoorryy
Version 4.0
CHILD REPORT (ages 8-12) 
ID# 
Date:

PedsQL 4.0 - Parent (8-12) 
01/00
Not to be reproduced without permission
Copyright © 1998 JW Varni, Ph.D. All rights reserved
PedsQL-4.0-Core-PC
United States/English
Original version
PedsQL-4.0-Core-PC_AU4.0_eng-USori
DIRECTIONS
On the following page is a list of things that might be a problem for your child. 
Please tell us how much of a problem each one has been for your child 
during the past ONE month by circling:
0 if it is never a problem
1 if it is almost never a problem
2 if it is sometimes a problem
3 if it is often a problem
4 if it is almost always a problem
There are no right or wrong answers.
If you do not understand a question, please ask for help.
PedsQL
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee
IInnvveennttoorryy
Version 4.0
PARENT REPORT for CHILDREN (ages 8-12) 
ID# 
Date:

PedsQL 4.0 - Parent (13-18) 
01/00
Not to be reproduced without permission
Copyright © 1998 JW Varni, Ph.D. All rights reserved
PedsQL-4.0-Core-PA
United States/English
Original version
PedsQL-4.0-Core-PA_AU4.0_eng-USori
DIRECTIONS
On the following page is a list of things that might be a problem for your teen. 
Please tell us how much of a problem each one has been for your teen 
during the past ONE month by circling:
0 if it is never a problem
1 if it is almost never a problem
2 if it is sometimes a problem
3 if it is often a problem
4 if it is almost always a problem
There are no right or wrong answers.
If you do not understand a question, please ask for help.
PedsQL
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee
IInnvveennttoorryy
Version 4.0
PARENT REPORT for TEENS (ages 13-18) 
ID#
Date:

PedsQL 4.0 - (13-18) 
01/00
Not to be reproduced without permission
Copyright © 1998 JW Varni, Ph.D. All rights reserved
PedsQL-4.0-Core-A
United States/English
Original version
PedsQL-4.0-Core-A_AU4.0_eng-USori
DIRECTIONS
On the following page is a list of things that might be a problem for you. 
Please tell us how much of a problem each one has been for you 
during the past ONE month by circling:
0 if it is never a problem
1 if it is almost never a problem
2 if it is sometimes a problem
3 if it is often a problem
4 if it is almost always a problem
There are no right or wrong answers.
If you do not understand a question, please ask for help.
PedsQL
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee
IInnvveennttoorryy
Version 4.0
TEEN REPORT (ages 13-18) 
ID# 
Date:

PedsQL 4.0 - (18-25) 
2/07
Not to be reproduced without permission
Copyright © 1998 JW Varni, Ph.D. All rights reserved
PedsQL-4.0-Core-Yad
United States/English
Original version
PedsQL-4.0-Core-Yad_AU4.0_eng-USori
DIRECTIONS
On the following page is a list of things that might be a problem for you. 
Please tell us how much of a problem each one has been for you 
during the past ONE month by circling:
0 if it is never a problem
1 if it is almost never a problem
2 if it is sometimes a problem
3 if it is often a problem
4 if it is almost always a problem
There are no right or wrong answers.
If you do not understand a question, please ask for help.
PedsQL
YYoouunngg AAdduulltt Q
Quuaalliittyy ooff LLiiffee
IInnvveennttoorryy
Version 4.0
YOUNG ADULT REPORT (ages 18-25) 
ID# 
Date:

 
A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
 
 
Appendix 5 
Guideline for Fat-Soluble Vitamin Supplementation 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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Amendment 6.2 Sweden, 11 February 2022
Page 1 of 2
Appendix 5: Guideline for Fat-Soluble Vitamin Supplementation
Cholestasis predisposes to fat-soluble vitamin deficiencies. Fat-soluble vitamin levels, 
i.e., vitamins A and E, 25-hydroxy vitamin D, and INR (surrogate for vitamin K) are 
measured routinely during the study. If a patient has any fat-soluble vitamin level(s) that 
are out of range, vitamin supplementation adjustments may be required. Below are 
suggested guidelines for fat-soluble vitamin deficiency treatment [Venkat 20014; 
Shneider 2012]. Additional patient monitoring and/or treatment strategies may be 
warranted at the discretion of the investigator. 
Target Fat-soluble Vitamin Levels and Replacement Regimens
Vitamin
Target Range 
(Serum Level)
Supplementation Strategy
A (retinol)
19 to 77 µg/dL* 
retinol:retinol-binding 
protein molar ratio > 0.8 
Increments of 5000 IU (up to 25,000 
to 50,000 IU/day) orally or monthly 
intramuscular administration of 
50,000 IU**
D (25-hydroxy 
vitamin D)
15 to 45 ng/mL*
Increments of 1200 to 8000 IU 
orally daily of cholecalciferol or 
ergocalciferol; alternatively
calcitriol at 0.05 to 0.2 µg/kg/day*
tocopherol)
3.8 to 20.3 µg/mL 
vitamin E:total serum 
lipids ratio >0.6 mg/g
Increments of 25 IU/kg of
d- -tocopheryl polyethylene glycol 
– 1000 succinate (TPGS) orally 
daily (to 100 IU/kg/day)
K (phytonadione)
INR 1.2
1.2 <INR 1.5: 2.5 mg
vitamin K orally daily
1.5 <INR 1.8: 2.0 to 5.0 mg
vitamin K intramuscular and
2.5 mg vitamin K orally daily
INR >1.8: 2.0 to 5.0 mg vitamin 
K intramuscular and 5.0 mg 
vitamin K orally daily
*Clinical practice may vary. This is meant as a guidance only and does not override local standard of care. Investigators
should provide best case practices for management and treatment

A4250 – IND 130591 
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Amendment 6.2 Sweden, 11 February 2022 
Page 2 of 2 
 
 
 
** For further detail regarding age related Tolerable Upper Intake (UL) for preformed vitamin A please refer to page 163 in 
the European Food Safety Authority guidance: Tolerable Upper Intake Levels for Vitamins and Minerals; Scientific Committee 
on food Scientific Panel on Dietetic Products, Nutrition and Allergies 
http://www.efsa.europa.eu/sites/default/files/efsa_rep/blobserver_assets/ndatolerableuil.pdf 

 
A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
 
 
Appendix 6 
Contraceptive Requirements 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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Amendment 6.2 Sweden, 11 February 2022
Page 1 of 2
Appendix 6: Contraceptive Requirements
A woman is considered of childbearing potential (WOCBP), i.e. fertile, following 
menarche and until becoming post-menopausal unless permanently sterile. Permanent 
sterilisation methods include hysterectomy, bilateral salpingectomy and bilateral 
oophorectomy.
Contraceptive methods, or combinations of contraceptive methods, for males and females 
that can achieve a failure rate of less than 1% per year when used consistently and 
correctly are considered as highly effective birth control methods and must be used at 
least to up to 90 days following the last day of treatment. 
Such methods include:
Combined (estrogen and progestogen containing) hormonal contraception 
associated with inhibition of ovulation:
o oral
o intravaginal
o transdermal
Progestogen-only hormonal contraception associated with inhibition of ovulation:
o oral
o injectable
o implantable
Intrauterine device (IUD)
Intrauterine hormone-releasing system (IUS) 
Bilateral tubal occlusion
Vasectomised partner 
 
Sexual abstinence 
Sexual abstinence is considered a highly effective method only if defined as refraining 
from heterosexual intercourse during the entire study period up to at least 90 days after 
the last day of treatment. The reliability of sexual abstinence needs to be evaluated in 
relation to the duration of the clinical trial and the preferred and usual lifestyle of the 

A4250 – IND 130591 
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M5.3.5.1 – Protocol A4250-008 
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Amendment 6.2 Sweden, 11 February 2022 
Page 2 of 2 
 
 
 
subject. Periodic abstinence (e.g., calendar, ovulation, symptothermal, post-ovulation 
methods) and withdrawal are not acceptable methods of contraception. 
Requirements according to “Recommendations related to contraception and pregnancy 
testing in clinical trials”, HMA CTFG (Clinical Trial Facilitation Group), 2014 

 
A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
 
 
Appendix 7 
Blood Volumes 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confidential 
124 
Amendment 6.2 Sweden, 11 February 2022 

ICON Central Laboratories 
Scientific Affairs 
Estimated Blood Volume Request 
Version: 15.0 
Protocol#: A4250-008 
SPONSOR: Albireo 
Age Group 0 months to 30 years of age 
Estimated Blood Volume Request (MS Excel) 
Eff. 25 October 2011, Vs. 1 
QS#: MA706App105 
Page 3 of 3 
 
 
Visit^ 
Testing^1-9 
Tube 
volume 
(mL) 
Tube 
Type 
# of 
Collection 
Tubes 
# of 
Aliquots 
Volume 
(mLs) 
Volume/ 
visit 
(mL) 
Volume/
visit 
(tsp) 
Volume/ 
visit 
(TBS) 
#5. Autotaxin serum samples will be tested at LGC 
#6. For subjects requiring optional pregnancy testing, collect 1.1 mL SST 
#7. Optional Sample. Only collected if required 
#8. Collection requirements for Extension Period Visit added per provision of schedule of assessments provided by sponsor for utiliztion in an upcoming revised protocol. 
#9. For patients who experience a hepatic adverse event and/or hepatic decompensation, collect 1.1. mL Plasma for PK 
 
Created by: Jennifer Rodriguez, Protocol Review 
Date: 19-Mar-2020 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.1 UK, 11 February 2022 
1 
 
 
 
CLINICAL STUDY PROTOCOL A4250-008 
An Open-label Extension Study to Evaluate Long-term Efficacy and Safety of A4250 in 
Children with Progressive Familial Intrahepatic Cholestasis Types 1 and 2 (PEDFIC 2) 
 
 
IND Number: 
130591 
EudraCT Number 
2017-002325-38 
 
Text Product: 
A4250 
 
Indication: 
Progressive Familial Intrahepatic Cholestasis (PFIC) 
 
Sponsor: 
Albireo AB 
 
Development Phase: 
Phase 3 
 
Sponsor Signatory: 
 Philip Stein, MD 
Sponsor Medical Monitor: 
 
Principal Investigator: 
Richard Thompson, MD, PhD 
Date of the Protocol: 
11 February 2022 
Version of the Protocol: 
Amendment 6.1 UK 
 
 
 
 
 
 
 
 
 
Confidential 
 
The information in this document contains trade secrets and commercial information that are privileged or 
confidential and may not be used, divulged, published, or otherwise disclosed without the written consent of 
Albireo AB. These restrictions on disclosure apply equally to all future information supplied to you or 
generated by you in connection with the study. 
PPD

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
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Amendment 6.1 UK, 11 February 2022 
2 
 
 
 
 
SPONSOR SIGNATURE PAGE 
PROTOCOL TITLE: An Open-label Extension Study to Evaluate Long-term Efficacy 
and Safety of A4250 in Children with Progressive Familial Intrahepatic Cholestasis 
Types 1 and 2 (PEDFIC 2) 
 
 
PROTOCOL NUMBER: A4250-008 
 
 
Albireo AB 
 
Date (day/month/year) 
PPD

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.1 UK, 11 February 2022 
3 
 
 
 
INVESTIGATOR SIGNATURE PAGE 
 
 
PROTOCOL TITLE: An Open-label Extension Study to Evaluate Long-term Efficacy 
and Safety of A4250 in Children with Progressive Familial Intrahepatic Cholestasis 
Types 1 and 2 (PEDFIC 2) 
 
 
PROTOCOL NUMBER: A4250-008 
I have read this protocol and agree that it contains all necessary details for performing this 
study. I will conduct the study as outlined herein and will complete the study within the time 
designated, in accordance with all stipulations of the protocol and in accordance with Good 
Clinical Practice (GCP), local regulatory requirements, and the Declaration of Helsinki. 
I will provide copies of the protocol and all pertinent information to all individuals responsible 
to me who assist in the conduct of this study. I will discuss this material with them to ensure 
that they are fully informed regarding the study drug and the conduct of the study. 
I will use only the informed consent approved by the Independent Ethics Committee 
(IEC)/Institutional Review Board (IRB) and will fulfil all responsibilities for submitting 
pertinent information to the IEC/IRB responsible for this study. 
I agree that the Sponsor (Albireo AB) shall have access to any source documents from which 
case report form information may have been generated. 
I further agree not to originate or use the name of Albireo AB or A4250 in any publicity, news 
release, or other public announcement, written or oral, whether to the public, press, or 
otherwise, relating to this protocol, to any amendment to the protocol, or to the performance of 
this protocol without the prior written consent of Albireo AB. 
 
 
 
 
 
Name of Investigator 
 
 
 
 
 
Signature 
Date (day/month/year) 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
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Amendment 6.1 UK, 11 February 2022 
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1 
ADMINISTRATIVE INFORMATION 
An Open-label Extension Study to Evaluate Long-term Efficacy and Safety of A4250 in 
Children with Progressive Familial Intrahepatic Cholestasis Types 1 and 2 (PEDFIC 2) 
Protocol No.: 
A4250-008 
Date of the initial Protocol: 
24 August 2017 
Date and Number of Amendment(s): 
Amendment 01, 18 April 2018 
Amendment 02, 18 January 2019 
Amendment 3.2 UK, 10 July 2019 
Amendment 4.1 UK, 06 November 2019 
Amendment 5.1 UK, 25 March 2020 
Amendment 6.1 UK, 11 February 2022 
Sponsor: 
Albireo AB 
Arvid Wallgrens Backe 20 
413 46 Göteborg 
Sweden 
Clinical Research Organization: 
ICON Clinical Research Ltd 
South County Business Park 
Leopardstown, Dublin 18, 
D18 X5R3 
Ireland 
Sponsor Signatory: 
Philip Stein, MD 
Albireo Pharma, Inc. 
10 Post Office Square, Suite 502 South 
Boston, MA 02109 
United States 
Tel 
 
Sponsor Medical Monitor: 
 
Tel 
 
Principal Investigator: 
Richard Thompson, MD, PhD 
SE5 9RS, London 
United Kingdom 
Tel 
Fax
 
PPD
PPD
PPD
PPD
PPD

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.1 UK, 11 February 2022 
5 
 
 
 
2 
STUDY SYNOPSIS 
 
Name of Sponsor/Company: 
Albireo AB 
Name of Product: 
A4250 
Name of Active Ingredient: 
A4250 
Title of Study: 
An Open-label Extension Study to Evaluate Long-term Efficacy and Safety of A4250 in Children with 
Progressive Familial Intrahepatic Cholestasis Types 1 and 2 (PEDFIC 2) 
Principal Investigator: 
Richard Thompson, MD, PhD 
Study Centers: 
Up to 50 sites will be included in this study in the United States (US), Canada, Europe, Australia, and Middle 
East. 
Publication(s): 
None. 
Planned Study Period: 
Q3 2018 to Q3 2023 
Development Phase: 
Phase 3 
Objectives: 
Primary Objective (Cohort 1) 
To demonstrate a sustained effect of A4250 on serum bile acids and pruritus in children with progressive 
familial intrahepatic cholestasis (PFIC) Types 1 and 2. 
Primary Objective (Cohort 2) 
To evaluate the effect of A4250 on serum bile acids and pruritus in patients with PFIC who either (1) do not 
meet eligibility criteria for Study A4250-005 (PEDFIC 1) or (2) patients who do meet the eligibility criteria 
for Study A4250-005 after recruitment of Study A4250-005 has been completed. 
Secondary Objectives (Cohorts 1 and 2) 
To evaluate the long-term safety and tolerability of repeated daily doses of A4250 
To evaluate the effect of A4250 on growth 
To evaluate the effect of A4250 on biliary diversion and/or liver transplantation 
To evaluate the effect of A4250 on biochemical markers of cholestasis and liver disease 
Methodology: 
This is a Phase 3, multi-center, open-label extension study to investigate the long-term efficacy and safety of a 
120 µg/kg/day daily dose of A4250 in patients with PFIC, including episodic forms also referred to as benign 
recurrent intrahepatic cholestasis (BRIC). Cohort 1 will consist of children with PFIC Types 1 and 2 who have 
participated in study A4250-005. Cohort 2 will consist of approximately 60 patients with PFIC who have 
elevated serum bile acids and cholestatic pruritus and who either (1) do not meet eligibility criteria for Study 
A4250-005 (PEDFIC 1) or (2) are eligible for enrolment in A4250-005 after recruitment of study A4250-005 
has been completed. Up to 40 patients post biliary diversion surgery are allowed to participate in Cohort 2. 
Eligible patients will be enrolled into this open-label extension study and treated with a daily dose of 
40 µg/kg/day1 or 120 µg/kg/day of A4250 for 72 weeks, or 40 µg/kg/day for the first 12 weeks followed by 
120 µg/kg/day for the remaining 60 weeks1. Patients not tolerating the 120 µg/kg/day dose after a minimum 
of 1 week will have the option to down-titrate to a lower dose (40 µg/kg/day). The patient should return to 
the higher dose as soon as deemed appropriate by the investigator. More than one upward dose titration 
(from 40 µg/kg/day directly to 120 µg/kg/day) for the same event is not recommended. Any dose titration 
should be done in consultation with the sponsor Medical Monitor or designee. 
 
1 As of Protocol Amendment 6.1 UK, patients entering Cohort 2 will start treatment at 40 µg/kg/day with 
the possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus based 
on investigator judgment. 

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Confidential
Amendment 6.1 UK, 11 February 2022
6
Name of Sponsor/Company:
Albireo AB
Name of Product:
A4250
Name of Active Ingredient:
A4250
Patients who wish to continue receiving A4250 after 72 weeks, will have the option to remain on treatment 
until the drug is commercially available, provided continued use is supported by the risk-benefit profile and 
the subject has not been previously withdrawn or discontinued from the study.
The primary analysis will be performed after the last patient (from Cohort 1 or 2) completes the 72-week 
treatment period. Analyses during the extension period will consist of safety summaries and other evaluations 
on an ongoing basis per the schedule of assessment for the extension period.
Number of Patients:
Approximately 120 patients in total. Approximately 60 patients will be enrolled following participation in 
Study A4250-005 (Cohort 1) and approximately 60 patients will be enrolled directly into this study (Cohort 2).
Diagnosis and Main Criteria for Inclusion:
Cohort 1:
1.
Completion
of
the 24-week
Treatment
Period
of
Study
A4250-005
or withdrawn from 
Study A4250-005 due to patient/caregiver judgment of intolerable symptoms after completing at least 
12 weeks of treatment. Patients who withdraw from A4250-005 due to a study drug related adverse 
event (AE) will not be eligible.
2.
Signed informed consent and assent as appropriate. Patients who turn 18 years of age (or legal age 
per country) during the study will be required to re-consent to remain on the study.
3.
Patients expected to have a consistent caregiver for the duration of the study.
4.
Caregivers (and age-appropriate patients) must be willing and able to use an electronic diary 
(eDiary) device as required by the study.
Cohort 2:
1.
A male or female patient of any age, with a clinical diagnosis of PFIC, including episodic forms 
(i.e., BRIC), and with a body weight 5 kg at Visit S-1.
2.
Patient must have clinical genetic confirmation of PFIC.
3.
Patients with PFIC, excluding BRIC, must have elevated serum bile acid concentration, specifically 
measured to be
at least 7 days apart (Visits S-1 and 
S-2) prior to the Screening/Inclusion Visit (Visit 1).
4.
Patients with PFIC, excluding BRIC, must have history of significant pruritus and a caregiver- 
reported observed scratching or patient-reported itching (for patients >18 with no caregiver-reported 
observed scratching) 
the
Screening/Inclusion Visit (Visit 1).
5.
Patients with episodic forms of PFIC (i.e., BRIC) must have an emerging flare characterized by 
clinically significant pruritus and elevated serum bile acid levels/cholestasis as judged by the 
investigator.
6.
Patient and/or legal guardian must sign informed consent (and assent) as appropriate. Patients who 
turn 18 years of age (or legal age per country) during the study will be required to re-consent in 
order to remain in the study.
7.
Age-appropriate patients are expected to have a consistent caregiver for the duration of the study.
8.
Caregivers and age-
, if able) must be willing and able to use an 
eDiary device as required by the study.
Test Product, Dose and Mode of Administration:
A4250, 40 or 120 µg/kg/day orally administered.
Reference Therapy, Dose and Duration of Administration:
Not applicable.
Duration of Treatment:
72 weeks
Variables:

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.1 UK, 11 February 2022 
7 
 
 
 
Name of Sponsor/Company: 
Albireo AB 
Name of Product: 
A4250 
Name of Active Ingredient: 
A4250 
Efficacy: 
Primary Efficacy Endpoints 
European Union (EU) and rest of world: Change from baseline in serum bile acids after 72 weeks of 
treatment. 
US: Proportion of positive pruritus assessments at the patient level over the 72-week treatment period using 
the Albireo observer-reported outcome (ObsRO) instrument. 
Secondary Efficacy Endpoints 
EU and rest of world: Proportion of positive pruritus assessments at the patient level over the 72-week 
treatment period using the Albireo ObsRO instrument. 
US: Change from baseline in serum bile acids after 72 weeks of treatment. 
All Regions: 
Change from baseline in serum bile acids at Weeks 4, 12, 22, 24, 36, 46, 48, 60, 70, 72, and 76 
Proportion of individual assessments meeting the definition of a positive pruritus assessment at the 
patient level using the Albireo ObsRO instrument from Weeks 0-4, Weeks 0-12, Weeks 0-22, 
Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, Weeks 0-60, and Weeks 0-70, respectively, or 
the proportion of positive pruritus assessments at each 4-week interval between Visit 1/Screening 
and Visit 5/Week 24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 
Proportion of individual AM assessments meeting the definition of a positive pruritus assessment at 
the patient level using the Albireo ObsRO instrument from Weeks 0-4, Weeks 0-12, Weeks 0-22, 
Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, Weeks 0-60, Weeks 0-70, and Weeks 0-72, 
respectively, or the proportion of positive pruritus assessments at each 4-week interval between 
Visit 1/Screening and Visit 5/Week 24, then by each visit between Visit 5/Week 24 to 
Visit 12/Week 76 
Proportion of individual PM assessments meeting the definition of a positive pruritus assessment at 
the patient level using the Albireo ObsRO instrument from Weeks 0-4, Weeks 0-12, Weeks 0-22, 
Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, Weeks 0-60, Weeks 0-70, and Weeks 0-72, 
respectively, or the proportion of positive pruritus assessments at each 4-week interval between 
Visit 1/Screening and Visit 5/Week 24, then by each visit between Visit 5/Week 24 to 
Visit 12/Week 76 
All-cause mortality, number of patients undergoing biliary diversion surgery or liver transplantation. 
These parameters will be evaluated separately and together at weeks 24, 48, and 72 
Change in growth from baseline to Weeks 24, 48, and 72 after initiation of A4250 treatment, defined 
as the linear growth deficit (height/length for age, weight for age, mid-arm circumference and body 
mass index [BMI]) compared to a standard growth curve (Z-score, standard deviation [SD] from P50) 
Change in aspartate aminotransferase (AST) to platelet ratio index (APRI) score and fibrosis-4 (Fib-4) 
score from baseline to Week 72 
Change in pediatric end-stage liver disease (PELD)/model for end-stage liver disease (MELD) score 
from baseline to Week 72 
Change in use of antipruritic medication at Weeks 24, 48, and 72 
Exploratory Efficacy Endpoints 
All Exploratory Endpoints will be evaluated at Weeks 24, 48, and 72 unless otherwise noted. Baseline is 
calculated prior to initiation of A4250 treatment. Exploratory endpoints include: 
Change in serum alanine aminotransferase (ALT), gamma-glutamyl transferase, and total bilirubin 
concentration from baseline to Week 72 

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Confidential
Amendment 6.1 UK, 11 February 2022
8
Name of Sponsor/Company:
Albireo AB
Name of Product:
A4250
Name of Active Ingredient:
A4250
Proportion of individual assessments meeting the definition of a positive pruritus assessment at the 
patient level over the 72-week Treatment Period. A positive pruritus assessment includes an itch score
-point drop from baseline based on the Albireo patient-reported outcome (PRO) 
instrument;
years of age will complete the Albireo PRO instrument
Change from baseline over the 72-week treatment period in sleep parameters measured with the 
Albireo PRO and ObsRO instruments
Change from baseline in international normalized ratio, albumin, liver enzymes, leukocytes, and 
platelets
Change from baseline
-hydroxy-4-cholesten-3-
one [p-C4])
Assessment of Global Symptom Relief at weeks 4, 12, 24, 48 and 72 as measured by patient, caregiver, 
and clinician global impression of change (PGIC) items
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then 
by each visit between Visit 5/Week 24 to Visit 12/Week 76 in patient-reported and observer-reported 
night time itching and scratching severity scores, respectively
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then 
by each visit between Visit 5/Week 24 to Visit 12/Week 76 in patient-reported and observer-reported 
morning time itching and scratching severity scores, respectively
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then 
by each visit between Visit 5/Week 24 to Visit 12/Week 76 in pooled pruritus score including 
observer-reported scratching for patients <8 years of age and patient-reported itch severity for patients
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then 
by each visit between Visit 5/Week 24 to Visit 12/Week 76 in additional patient-reported and 
observer-reported sleep parameters (e.g., tiredness, number of awakenings)
Change from baseline in Pediatric Quality of Life Inventory (PedsQL) questionnaire 
Change from baseline in stage of liver fibrosis as assessed by Fibroscan® (where available)
Change from baseline in stage of liver fibrosis as assessed by post-treatment biopsy (when available)
Safety:
Safety criteria are as follows:
Occurrence of treatment-emergent AEs including severity and relatedness to study drug at all visits
The incidence of treatment-emergent serious adverse events (SAEs), based upon information from 
patient reports, including the description, causality, and severity of an SAE
Trends evaluated for the following assessments: physical examinations, concomitant medications, 
vital signs, laboratory test results (including clinical chemistry, hematology, urinalysis, alfa- 
fetoprotein, and vitamins A, E, and 25-hydroxy vitamin D), and abdominal ultrasound
Statistical Methods:
Descriptive statistics will mainly be used in this open-label extension study.
Baseline 1 will be defined as the last value prior to treatment start in study A4250-005 for Cohort 1 patients.
Baseline 2 will be defined as the last value prior to treatment start in Study A4250-008 for all patients. 
Baseline 2 will be used in all analyses unless otherwise specified.
The full analysis set (FAS) will consist of all patients who received at least 1 dose of study drug in Study 
A4250-008. The full analysis set will be the primary analysis set for all analyses unless otherwise specified. 
Evaluation of Primary Efficacy Variables:
The proportion of positive pruritus assessments at the patient level over the 72-week treatment period will be 
summarized.
-point drop
from baseline on the Albireo ObsRO instrument. At each assessment, the AM score will be compared to the
baseline AM average, and the PM score will be compared to the baseline PM average. Both AM and PM

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
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Amendment 6.1 UK, 11 February 2022 
9 
 
 
 
Name of Sponsor/Company: 
Albireo AB 
Name of Product: 
A4250 
Name of Active Ingredient: 
A4250 
pruritus assessments will be included in the analysis of this endpoint. Baseline will be defined as the average 
score from 14 days prior to treatment start in A4250-008 for AM and PM, respectively. 
The change from baseline over the treatment period in serum bile acids will be analyzed mainly by using 
descriptive statistics. Fasting serum bile acids baseline will be calculated as the average of the pre-dose value 
in Study A4250-008 (Visit 1) and the previous visit (Visit 8 in study A4250-005) for Cohort 1. Fasting 
serum bile acids baseline will be calculated as the average of Visit S-2 and the pre-dose Visit 1 values in 
Study A4250-008 for Cohort 2. The end value is the average of the values at Weeks 70 and 72 in study 
A4250-008. 
Descriptive statistics will be summarized for Cohort 1, Cohort 2 excluding BRIC, Cohort 2 BRIC, and 
combined Cohort 1 + Cohort 2 excluding BRIC. Within Cohort 1, the following subgroups will be 
presented: ‘A4250 40 µg/kg/day (-005) to 120 µg/kg/day (-008)’, ‘A4250 120 µg/kg/day (-005) to 120 
µg/kg/day (-008)’, ‘A4250 40 µg/kg/day (-005) and 120 µg/kg/day (-005) to 120 µg/kg/day (-008)’, and 
‘placebo (-005) to 120 µg/kg/day (-008)’. Within Cohort 2 excluding BRIC, 3 subgroups (‘40 µg/kg/day’, 
‘40 µg/kg/day to 120 µg/kg/day’, and ‘120 µg/kg/day’) will be presented. Cohort 1 Placebo to A4250 
120 µg/kg/day will also be combined with Cohort 2 excluding BRIC for presentations. Change over time 
will also be displayed using graphical presentations (e.g., a spaghetti plot which illustrates the change in both 
Study A4250-005 and Study A4250-008 by treatment group in Study A4250-005). 
Evaluation of Secondary and Exploratory Efficacy Variables: 
All secondary and exploratory variables will be analyzed descriptively for categorical and continuous data, as 
applicable. For continuous data, the change from baseline will be analyzed in addition to the actual visit values. 
For categorical data, shift tables or frequency and percentages of patients will be presented as appropriate. 
Change in growth (Z-score, SD from P50 standard growth curve) will be analyzed by using one-sample T-test 
or Wilcoxon signed-rank test as appropriate. Change in growth (height/length for age, weight for age, mid- 
arm circumference and BMI) will also be displayed using graphical presentations. 
A 95% confidence interval (CI) will be calculated for the proportion of patients with at least one event, i.e., 
bile diversion or liver transplantation or death. The upper boundary will be compared to the expected 
proportion of events, using the event probability estimated from the untreated reference population in an 
ongoing observational cohort study. 
Time to first event, i.e., time to surgical bile diversion or liver transplantation or death, will be explored by 
descriptive statistics and Kaplan-Meier curves, which also will be used to make a comparison to the untreated 
reference population. 
Evaluation of Safety Variables: 
Safety data will be analyzed using descriptive statistics and summaries overall of SAEs, AEs, vital signs, 
clinical laboratory tests (hematology, clinical chemistry and urinalysis) and concomitant medication. Analyses 
will be performed using the full analysis set. 
Sample Size Determination: 
There is no formal hypothesis testing in this open label-study. Sample size for Cohort 1 was determined in 
Study A4250-005. For Cohort 1, patients will be enrolled following completion or participation of at least 12 
weeks of Study A4250-005. The expected proportion of patients with at least one event, i.e., surgical bile 
diversion or liver transplantation or death, in untreated patients is expected to be high enough to be able to 
detect an improvement after A4250 treatment. If the expected proportion with at least one event is estimated 
to be 30% in the study population of Cohort 1, and then if the proportion of patients with at least one event 
during A4250 long-term treatment are shown to be only 10% in the study, the power is approximately 89% to 
96% (1-sided test, alpha=2.5%) for a CI with upper boundary <30% based on a sample size of n=48 to 60. The 
sample size of 60 patients for Cohort 2 was estimated based on the availability of target patient population to 
evaluate the therapeutic benefit for those patients. 
Date of the Protocol: 11 February 2022 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.1 UK, 11 February 2022 
10 
 
 
 
3 
TABLE OF CONTENTS 
1 
ADMINISTRATIVE INFORMATION ................................................................... 4 
2 
STUDY SYNOPSIS ................................................................................................. 5 
3 
TABLE OF CONTENTS ....................................................................................... 10 
3.1 
List of Tables ............................................................................................ 14 
3.2 
List of Figures ........................................................................................... 14 
3.3 
List of Appendices and Supplements ........................................................ 14 
4 
LIST OF ABBREVIATIONS AND DEFINITION OF TERMS .......................... 15 
5 
INTRODUCTION .................................................................................................. 18 
5.1 
Investigational Medicinal Product ............................................................ 18 
5.2 
Background ............................................................................................... 18 
5.2.1 
Progressive Familial Intrahepatic Cholestasis ...................................... 18 
5.2.2 
Summary of Clinical and Nonclinical Studies ..................................... 20 
5.3 
Rationale .................................................................................................... 22 
5.3.1 
Risk/Benefit ........................................................................................... 24 
5.3.2 
Risk/Benefit  of  Receiving  COVID-19  Vaccine  during  Trial 
Participation ........................................................................................... 25 
6 
STUDY OBJECTIVES .......................................................................................... 26 
6.1 
Primary Objectives .................................................................................... 26 
6.2 
Secondary Objectives ................................................................................ 26 
7 
INVESTIGATIONAL PLAN ................................................................................ 27 
7.1 
Overall Study Design and Plan. ................................................................ 27 
7.1.1 
Description ............................................................................................. 27 
7.1.2 
Schedule of Assessments ....................................................................... 31 
7.1.3 
Study Procedures and Assessments....................................................... 38 
7.1.3.1 
Screening Period (Days -56 to 0) (For Cohort 2 only) ......... 39 
7.1.3.2 
Treatment Period ................................................................... 40 
7.1.3.3 
End of Treatment/Early Termination/Start of Optional 
Extension Period .................................................................... 45 
7.1.3.4 
Follow-up Visit ..................................................................... 45 
7.1.3.5 
Optional Extension Period .................................................... 46 
7.1.3.6 
Optional Extension Period End of Treatment ....................... 46 
7.2 
Study Population ....................................................................................... 47 
7.2.1 
Inclusion Criteria ................................................................................... 47 
7.2.2 
Exclusion Criteria .................................................................................. 48 
7.2.3 
Withdrawal of Patients .......................................................................... 50 

A4250 – IND 130591 
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M5.3.5.1 – Protocol A4250-008 
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Amendment 6.1 UK, 11 February 2022 
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7.2.4 
Study Termination by Sponsor ............................................................. 51 
8 
TREATMENT OF PATIENTS .............................................................................. 52 
8.1 
Identity of Study Drug .............................................................................. 52 
8.2 
Administration of Study Drug .................................................................. 52 
8.3 
Study Drug Packaging and Labelling ....................................................... 54 
8.3.1 
Packaging and Labelling ....................................................................... 54 
8.3.2 
Storage ................................................................................................... 54 
8.3.3 
Blinding and Randomization of Study Drug ........................................ 54 
8.4 
Procedure for Breaking the Randomization Code .................................... 54 
8.5 
Patient Compliance ................................................................................... 54 
8.6 
Patient Identification ................................................................................. 55 
8.7 
Study Drug Accountability........................................................................ 55 
8.8 
Concomitant Therapy and Prohibited Medications .................................. 55 
9 
ASSESSMENT OF EFFICACY ............................................................................ 56 
9.1 
Efficacy Endpoints .................................................................................... 56 
9.1.1 
Primary Efficacy Endpoints .................................................................. 56 
9.1.2 
Secondary Efficacy Endpoints .............................................................. 56 
9.1.3 
Exploratory Efficacy Endpoints ............................................................ 57 
9.2 
Efficacy Assessments ................................................................................ 58 
9.2.1 
Serum Bile Acids .................................................................................. 58 
9.2.2 
Itching and Sleep Score ......................................................................... 58 
9.2.3 
Growth ................................................................................................... 59 
9.2.4 
Biomarker Samples ............................................................................... 59 
9.2.5 
Change of Antipruritic Medication ....................................................... 59 
9.2.6 
Quality of Life Questionnaire (PedsQL) ............................................... 59 
9.2.7 
PELD/MELD Score .............................................................................. 59 
9.2.8 
Fibroscan® ............................................................................................................................................. 60 
9.2.9 
Markers of Fibrosis ............................................................................... 60 
9.2.10 
Liver Biopsy .......................................................................................... 60 
9.2.11 
Global Impression of Change and Global Impression of Symptom 
Measures ................................................................................................ 60 
10 
ASSESSMENT OF SAFETY ................................................................................ 61 
10.1 
Adverse Events ......................................................................................... 61 
10.1.1 
Definitions and Investigator Assessments ............................................ 61 
10.1.1.1 Clinical Significance .............................................................. 61 
10.1.1.2 Serious Adverse Events ......................................................... 61 

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10.1.1.3 Severity Assessment .............................................................. 62 
10.1.1.4 Causality Assessment ............................................................ 62 
10.1.2 
Recording of Adverse Events ............................................................... 63 
10.1.3 
Recording and Reporting of Serious Adverse Events .......................... 64 
10.1.4 
Reporting of Suspected Unexpected Serious Adverse Reactions ........ 65 
10.2 
Laboratory Values/Vital Signs/Physical Examinations and Other Safety 
Assessments ............................................................................................... 66 
10.2.1 
Laboratory Assessments ........................................................................ 66 
10.2.2 
Individual Patient Safety Monitoring .................................................... 67 
10.2.2.1 Liver Monitoring.................................................................... 67 
10.2.2.2 Close Observation .................................................................. 68 
10.2.2.3 De-challenge/Re-challenge for Liver and Clinical Hepatitis 
Monitoring ............................................................................. 69 
10.2.2.4 Diarrhea ................................................................................. 69 
10.2.2.5 Fat-soluble Vitamin Deficiency ............................................ 70 
10.2.2.6 Treatment-emergent Iron Deficiency Anemia ...................... 70 
10.2.2.7 Re-challenge after Discontinuation/Interruption of Study 
Drug ....................................................................................... 70 
10.2.2.8 Monitoring after Permanent Discontinuation of Study Drug 
Due to Safety ......................................................................... 71 
10.2.3 
Demographics/Medical and Surgical History (For Cohort 2 only) ...... 71 
10.2.4 
Clinical Genetic Testing (For Cohort 2 only) ....................................... 71 
10.2.5 
Physical Examination ............................................................................ 71 
10.2.6 
Vital Signs ............................................................................................. 72 
10.2.7 
Abdominal ultrasound ........................................................................... 72 
10.2.8 
Overdose ................................................................................................ 72 
10.2.9 
Pregnancy .............................................................................................. 72 
11 
STATISTICAL EVALUATION ............................................................................ 74 
11.1 
Sample Size and Power............................................................................. 74 
11.2 
Statistical Methods .................................................................................... 74 
11.2.1 
Statistical Analysis Sets ........................................................................ 74 
11.2.2 
Methods of Statistical Analyses ............................................................ 74 
11.2.2.1 General Principles .................................................................. 74 
11.2.2.2 Missing Data .......................................................................... 75 
11.2.2.3 Demographic and Baseline Characteristics ........................... 75 
11.2.2.4 Subject Disposition ................................................................ 75 

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11.2.2.5 Evaluation of Primary Efficacy Variables ............................ 76 
11.2.2.6 Evaluation of Secondary and Exploratory Efficacy Variables 
. ............................................................................................ 76 
11.2.2.7 Evaluation of Safety Variables .............................................. 77 
11.2.2.8 Compliance and Exposure ..................................................... 77 
11.2.3 
Interim Analysis .................................................................................... 78 
11.2.4 
Data Safety Monitoring Board .............................................................. 78 
12 
DIRECT ACCESS TO SOURCE DATA/NOTES ................................................. 79 
13 
QUALITY CONTROL AND QUALITY ASSURANCE ...................................... 80 
13.1 
Conduct of the Study ................................................................................. 80 
13.2 
Study Monitoring ....................................................................................... 80 
14 
ETHICS ................................................................................................................... 82 
14.1 
Independent Ethics Committee/Institutional Review Board ..................... 82 
14.2 
Written Informed Consents and Assents ................................................... 82 
15 
DATA HANDLING AND RECORD KEEPING .................................................. 84 
15.1 
Case Report Forms/Source Data Handling. ............................................... 84 
15.2 
Retention of Essential Documents ............................................................. 84 
16 
FINANCING AND INSURANCE .......................................................................... 85 
17 
PUBLICATION POLICY ....................................................................................... 86 
18 
REFERENCE LIST ................................................................................................. 87 
19 
APPENDICES ......................................................................................................... 89 

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3.1 
List of Tables 
Table 1 
Schedule of Assessments (Screening Period through Follow-up Period).. 32 
Table 2 
Schedule of Assessments (Optional Extension Period) ............................... 38 
Table 3 
Dosing and Capsule Strength ........................................................................ 53 
Table 4 
Routine Laboratory Parameters .................................................................... 67 
 
 
3.2 
List of Figures 
Figure 1 
Study Design up to Protocol Amendment 5.1 UK ....................................... 30 
Figure 2 
Study Design for Cohort 2 as of Protocol Amendment 6.1 UK .................. 30 
 
 
3.3 
List of Appendices and Supplements 
Appendix 1 
Concomitant Medication Guidelines ............................................................ 89 
Appendix 2 
Diary Questions including Albireo Patient-Reported 
Outcomes/Observer-Reported Outcome Instrument .................................... 91 
Appendix 3 
Patient Global Impression of Change (PGIC) and Patient Global Impression 
of Symptoms (PGIS) ..................................................................................... 94 
Appendix 4 
Pediatric Quality of Life Inventory (PedQL) Questionnaire ........................ 99 
Appendix 5 
Guideline for Fat-Soluble Vitamin Supplementation ................................. 120 
Appendix 6 
Contraceptive Requirements ....................................................................... 123 
Appendix 7 
Blood Volumes ........................................................................................... 126 

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4 
LIST OF ABBREVIATIONS AND DEFINITION OF TERMS 
A4250 
odevixibat (non-proprietary name); Bylvay (brand name) 
ADME 
absorption, distribution, metabolism, and excretion 
AE(s) 
adverse event(s) 
AFP 
alfa-fetoprotein 
ALT 
alanine aminotransferase 
APRI 
AST to platelet ratio index 
ASBT 
apical sodium-dependent bile transporter (also known as IBAT) 
AST 
aspartate aminotransferase 
ATC 
Anatomical Therapeutic Chemical 
BMI 
body mass index 
BRIC 
benign recurrent intrahepatic cholestasis 
BSEP 
bile salt export pump 
CI 
confidence interval 
COVID-19 
coronavirus disease 2019 
CPK 
creatine phosphokinase 
CRA 
clinical research associate 
CYP 
cytochrome P450 
DDI 
drug-drug interaction 
DILI 
drug-induced liver injury 
DSMB 
Data and Safety Monitoring Board 
eCRF 
electronic case report form 
eDiary 
electronic diary 
EMA 
European Medicines Agency 
EOT 
End of Treatment 
EU 
European Union 
EudraCT 
 European Union drug regulatory agency clinical trial 
FAS 
full analysis set 
FDA 
(United States) Food and Drug Administration 
Fib-4 
fibrosis-4 
FIC1 
familial intrahepatic cholestasis-1 
FXR 
farnesoid X receptor 
GCP 
Good Clinical Practice 
GGT 
gamma-glutamyl transferase 
GI 
gastrointestinal 
IB 
Investigator’s Brochure 

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IBAT
ileal bile acid transporter (also known as ASBT)
ICF
informed consent form
ICH
International Council for Harmonisation
IEC
Independent Ethics Committee
INR
international normalized ratio
IRB
Institutional Review Board
iRIS
ICON Results Integration Services
IWRS
Interactive Web Response System
LDH
lactate dehydrogenase
LFT
liver function test
LPLV
last patient last visit
MDR3
multidrug-resistance protein 3 
MedDRA
Medical Dictionary for Regulatory Activities
MELD
model for end-stage liver disease
NAPPED
Natural Course and Prognosis of PFIC and Effect of Biliary 
Diversion
ObsRO
observer-reported outcome
PBC
primary biliary cholangitis
p-C4
 
-hydroxy-4-cholesten-3-one 
PCS
potentially clinically significant
PEDFIC 1 
Study A4250-005
PEDFIC 2 
Study A4250-008
PedsQL
Pediatric Quality of Life Inventory
PELD
pediatric end-stage liver disease
PFIC
progressive familial intrahepatic cholestasis
PGIC
patient global impression of change
PGIS
patient global impression of symptoms
P-gp
P-glycoprotein
PK
pharmacokinetic
PRO
patient-reported outcome
PT
prothrombin time
PVM
pharmacovigilance manager
QD
once daily
QoL
quality of life
SAE(s)
serious adverse event(s)
SAP
statistical analysis plan

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s-FGF19 
serum fibroblast growth factor 19 
SD 
standard deviation 
SOC 
system organ class 
SUSAR 
suspected unexpected serious adverse reaction 
TEAE(s) 
treatment-emergent adverse event(s) 
TJP2 
tight junction protein 2 
ULN 
upper limit of normal 
US 
United States 
WHO 
World Health Organization 

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5
INTRODUCTION
5.1
Investigational Medicinal Product
A4250 is a small molecule and a potent selective inhibitor of the ileal bile acid transporter 
(IBAT), also known as the apical sodium-dependent bile acid transporter (ASBT). IBAT is an 
integral brush border membrane glycoprotein that co-transports sodium and bile acids and 
appears to be a critical component in the regulation of the bile acid pool size in animals and 
man. This transporter, expressed in the distal ileum, is a key element in the enterohepatic 
circulation of bile acids since it facilitates the high-affinity, high-capacity reabsorption of bile 
acids.
Indeed, 95% of secreted bile acids are reabsorbed via IBAT [Hofmann 2009;
Miethke 2016]. A4250 is orally administered and acts locally in the gut where it binds 
reversibly to IBAT to decrease the reuptake of bile acids. A4250 has minimal systemic 
exposure at the predicted therapeutic dose ranges.
5.2
Background
5.2.1
Progressive Familial Intrahepatic Cholestasis
PFIC is a rare autosomal recessive cholestatic liver disease estimated to affect between one in 
every 50,000 to 100,000 children born worldwide. PFIC represents 10% to 15% of causes of 
cholestasis in children and 10% to 15% of liver transplantation indications in children. All 
types of PFIC exist worldwide and both sexes appear to be equally affected. 
The common underlying pathogenesis of PFIC is disruption of bile formation and bile transport 
through the liver [Jacquemin 2000]. The classification of PFIC has evolved over the years. 
The most commonly used subclassification is PFIC Types 1 to 6 which is based on the 
associated affected gene and described in more detail below.
PFIC, Type 1: also referred to as “Byler disease” or “familial intrahepatic cholestasis 1 
(FIC1) protein deficiency.” FIC1 protein is located on the canalicular membrane of 
hepatocytes and facilitates movement of aminophospholipids from the outer to inner leaflet 
of the plasma membrane of the hepatocyte. The ATP8B1 gene encodes FIC1 protein. 
Biallelic pathologic variants in the ATP8B1 gene are associated with FIC1 dysfunction and 
classified clinically as PFIC Type 1 disease.
PFIC, Type 2: also referred to as “Byler syndrome” or “bile salt export pump (BSEP) 
deficiency.” BSEP is a transporter protein that is expressed at the canalicular membrane 
of hepatocytes and is the primary exporter of bile acids. The ABCB11 gene encodes the 
BSEP protein. Biallelic pathologic variations in the ABCB11 gene is associated with BSEP 
dysfunction and is classified clinically as PFIC Type 2 disease.
PFIC, Type 3: is caused by a deficiency of the multidrug-resistance protein 3 (MDR3) due 
to mutations in the ABCB4 gene. MDR3 is a phospholipid translocase critical for 
phospholipid secretion.

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PFIC, Type 4 (tight junction protein 2 [TJP2] deficiency): is caused by biallelic mutations
in the TJP2 gene which encodes the tight junction protein 2 (TJP2) which is also called
zona occludens-2 [Bull 2018]. TJP2 is a cytoplasmic protein of cell-cell junctional 
complexes. While not part of the tight junction itself, tight junction proteins are closely 
associated with proteins that do form tight junctions, such as the claudins. 
PFIC, Type 5 (farnesoid X receptor [FXR] deficiency): Loss of function mutations in the 
NR1H4 gene encoding the farnesoid X receptor (FXR) result in PFIC5 [Sticova 2018]. FXR 
is a nuclear receptor activated by bile acids and is directly involved in the expression of
both BSEP and MDR3, proteins affected in PFIC2 and PFIC3, respectively [Gomez-Ospina
2016].
PFIC, Type 6 (MYO5B deficiency): PFIC6 results from defects in the Myo5B gene that 
codes for the actin-associated molecular motor known as MYO5B, which is essential for
the polarisation of hepatocytes as well as localising BSEP to the canalicular membrane 
[Vitale 2019].
Severe pruritus is common in children diagnosed with PFIC. Itching (and subsequent 
scratching) is a significant morbidity for these patients and their families [Suchy 2007]. A 
more severe degree of pruritus is experienced compared to patients with other forms of liver 
disease and to other pruritic conditions such as atopic dermatitis [Murray 2011]. In patients 
with PFIC, liver biopsy reveals canalicular cholestasis and, later, the appearance of portal 
fibrosis. Serum biochemistry indicates cholestasis with hyperbilirubinemia, elevated alanine 
aminotransferase (ALT) and aspartate aminotransferase (AST). The concentrations of bile
acids in serum are very high, while serum gamma-glutamyl transferase (GGT) activity (the 
exception being MDR3 variants) and cholesterol [Hori 2010] are normal. Symptoms of portal 
hypertension and liver failure will develop during the course of the disease [Davit-Spraul 2009;
Alissa 2008]. Symptoms develop early; median age at onset of symptoms is 2 months, and
78% of PFIC patients present with jaundice [Pawlikowska 2010]. The life-threatening and 
debilitating nature of PFIC is reflected by the fact that survival in those not resorting to surgery 
is 50% at 10 years of age and almost zero at 20 years of age. Approximately half of PFIC 
patients undergo liver transplantation [Davit-Spraul 2009] and treatment resistant pruritus is 
the leading indication for the surgical procedure partial external biliary diversion, mostly in 
PFIC Type 1 and 2 patients. 
PFIC is life-threatening and debilitating. Other than odevixibat (A4250 non-proprietary name), 
which is approved for the treatment of PFIC by the European Medicines Agency (EMA) and
for the treatment of pruritus in patients with PFIC by the United States Food and Drug 
Administration (US FDA), the therapeutic choices are restricted to non-specific therapy of the 
symptoms and signs of the disease such as nutritional support, preventing vitamin deficiencies, 
and treatment of extrahepatic features. Medical treatment options include off-label use of 
ursodeoxycholic acid, rifampin, antihistamines, and naltrexone. A minority of patients respond 
nominally and transiently to these interventions. Biliary diversion is used to decrease systemic 

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bile acids through interruption of the enterohepatic circulation and so avoid transplantation. 
Liver transplantation is typically only viewed as an option when patients have failed medical 
treatment and/or biliary diversion and have liver failure or persistent uncontrolled pruritus. 
Previously, the term benign recurrent intrahepatic cholestasis (BRIC) was used to identify a 
group of patients with episodic cholestasis including severe pruritus and jaundice. Genetic 
analysis of patients with episodic cholestasis have identified mutations in the ATP8B1 and 
ABCB11 genes (the same mutations as PFIC1 and PFIC2). It is now generally recognised that, 
within each subtype, PFIC and BRIC represent 2 extremes of a continuous spectrum of 
phenotypes of the one disease [Bull 2018; Stapelbroek 2010; Sticova 2018]. 
Genetic diagnosis of BRIC Type 1 or BRIC Type 2 is based on evidence of mutations in both 
alleles of the corresponding genes. While the age of first manifestation can vary widely, BRIC 
usually manifests before the second decade of life. There is great variability in terms of 
frequency (months to years), duration (several days to several months), and intensity of 
cholestatic episodes. Clinical symptoms may include pruritus, jaundice, fatigue, anorexia, and 
steatorrhea [Strubbe 2012; Sticova 2018]. 
During cholestatic episodes, serum bile acids and bilirubin are typically increased, while GGT 
and serum cholesterol levels are normal [Sticova 2018]. Aminotransferases may be slightly 
elevated. Liver biopsies have shown hepatocanalicular cholestasis without fibrosis during 
cholestatic episodes and normal histology during the asymptomatic period. 
Therapeutic options for BRIC have not been very effective, including statins, corticosteroids, 
cholestyramine, or ursodeoxycholic acid [Sticova 2018]. While improvement in pruritus and 
decreased duration of symptomatic episodes have been reported with rifampicin, severe 
hepatotoxicity after long-term administration has been reported in patients with cholestatic 
disorders. 
5.2.2 
Summary of Clinical and Nonclinical Studies 
This is a summary of nonclinical and clinical studies. More detail is provided in the 
Investigator Brochure ([IB] see A4250 IB). 
A4250 is a potent selective IBAT inhibitor with no safety signals seen in the safety 
pharmacological studies. In addition, no safety signals were seen in repeat-dose oral toxicity 
studies in rats with up to 26 weeks of daily dosing and in dogs with up to 39 weeks of daily 
dosing. A4250 showed no carcinogenic potential in 2-year carcinogenicity studies conducted 
in mice and rats. No safety signals were identified when A4250 was administered daily to 
juvenile rats from age 14 days to 63 days. Based on findings from animal reproduction studies, 
A4250 may cause cardiac malformations when a fetus is exposed during pregnancy. In 
pregnant rabbits treated orally with A4250 during organogenesis, an increased incidence of 
malformations in fetal heart, great blood vessels, and other vascular sites occurred at all doses; 
maternal systemic exposure at the lowest dose was 2.1 times the maximum recommended dose. 
No such malformations were observed when A4250 was administered to pregnant rats. A4250 

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had no effect on the reproductive performance, fertility, embryo-foetal development, or 
prenatal/postnatal development studies in rats.
A4250 is minimally absorbed with very low systemic exposure in both humans and other 
species. In blood, protein binding is high (>99.7%). Systemically absorbed A4250 is slowly 
metabolized in humans and in preclinical studies by hydroxylation only, a metabolite that
retains IBAT activity.  A4250 did not show any significant inhibition of cytochrome 
P450 (CYP)
enzymes
in
the
rat.
A4250
inhibited
human
CYP3A4
and
CYP2D6 
(IC50: 16 µmol/L for both enzymes), and CYP2C9 (IC50: 1.2 µmol/L).
To date, A4250 has been studied in 6 completed Albireo-sponsored clinical studies: a study in 
healthy volunteers evaluating single and multiple administration of A4250; a single-dose 
absorption, distribution, metabolism, and excretion (ADME) study; a single-dose food 
interaction study in healthy subjects; a drug-drug interaction (DDI) study in healthy subjects; 
a Phase 2 study in children with cholestatic pruritus; and a Phase 3 study in children with PFIC. 
In addition, an investigator-sponsored study has been conducted in patients with primary biliary 
cholangitis (PBC). In total, 258 subjects/patients have been exposed to A4250 in completed
and ongoing studies.
In healthy volunteers (study A4250-001), dosing with A4250 at single doses of 0.1-10.0 mg
and multiple doses from 1-3 mg daily for up to 7 days induced anticipated changes in bile acid 
synthesis biomarkers (i.e., decreased serum fibroblast growth factor 19 [s-FGF19] and
increased 
hydroxy 4-cholesten-3-one [p-C4]). In addition, total plasma bile acids 
decreased and total fecal bile acids increased compared to placebo treatment.
The clinical development program has generated data demonstrating minimal systemic total 
exposure in the low nanomolar range with very high protein binding and no detectable levels 
of metabolites. An ADME study (A4250-007) demonstrated that A4250 is excreted unchanged 
primarily in the feces. A population pharmacokinetic (PK) analysis confirmed that A4250 
presented very low systemic exposure in pediatric patients with PFIC with rapid elimination.
No accumulation of A4250 is expected following repeated administration of therapeutic doses 
(40 and 120 µg/kg/day). No dose adjustment is required in subpopulations.
In a food interaction study (A4250-004) following administration of a single oral dose of
9.6 mg A4250, plasma concentrations and systemic exposure to A4250 were low, regardless 
of feeding status, indicating minimal absorption through the gastrointestinal (GI) tract. In a
DDI study (A4250-013), no clinically relevant drug-drug interactions with A4250 and a 
CYP3A4 substrate or a P-glycoprotein (P-gp) inhibitor were identified, although A4250 was a 
P-gp substrate. 
In a study with 4-week, once-daily oral treatment with A4250 in children with cholestatic liver 
disease and pruritus, A4250 reduced mean levels of serum bile acids in all treatment groups 
(5 dose groups ranging from 10-200 µg/kg/day [0.01-0.20 mg/kg/day]) (Study A4250-003). 
Patient-reported diaries documented improvement of the visual analogue scale (VAS)-itch

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score (Scale 0-10) in 17 of 24 patients during treatment, with the greatest improvement at a 
dose of 100 µg/kg/day. 
In a Phase 3 randomized double-blind study in children with PFIC, treatment with A4250 at 
doses of 40 and 120 µg/kg/day led to statistically significant reductions in serum bile acid levels 
and pruritus symptoms over 24 weeks compared with placebo (study A4250-005; PEDFIC 1). 
These improvements occurred rapidly and were sustained during continued treatment. Results 
for secondary and exploratory endpoints were generally consistent with the reductions in serum 
bile acids and pruritus showing improvements in sleep, hepatic biochemical parameters and 
hepatic health, and quality of life (QoL) measures. 
A4250 has been generally well tolerated in all completed studies. Adverse events (AEs) 
reported have primarily been of mild to moderate intensity. In total, 6 serious adverse events 
(SAEs) have been reported; none judged by the investigator to be causally related to the study 
drug. No deaths related to the drug have been reported. Abdominal pain and diarrhea have 
been the most prominent AEs in adults, while diarrhea, pyrexia, and upper respiratory tract 
infection have been the most commonly reported AEs in children. The most commonly 
reported study drug-related AEs in children were increases in alanine aminotransferase (ALT), 
aspartate aminotransferase (AST), and blood bilirubin. 
5.3 
Rationale 
The investigational product A4250 (non-proprietary name odevixibat; brand name Bylvay) has 
been approved for the treatment of PFIC by the EMA and for the treatment of pruritus in 
patients with PFIC by the US FDA. A4250 is also currently being developed for other orphan 
cholestatic liver diseases. 
In PFIC patients with severe pruritus, biliary diversion surgery is used to decrease systemic 
bile acids through interruption of the enterohepatic circulation and thereby reduce pruritus 
[Whitington 1988]. Liver transplantation is typically used as an option when patients have 
failed medical treatment and/or biliary diversion and have liver failure or persistent 
uncontrolled pruritus. 
By inhibiting IBAT with high selectivity and potency, A4250 has the potential to relieve 
cholestasis and improve liver function without surgical intervention in patients with PFIC. 
Since A4250 is minimally absorbed and achieves a substantial reduction of serum bile acids, it 
has the potential to be a safer and less invasive alternative to surgical biliary drainage. The 
rationale for using A4250 is to decrease serum bile acid levels, and to reduce the major 
morbidity of pruritus, improving the health and wellbeing of patients affected with PFIC. 
Ultimately, this noninvasive therapeutic approach has the potential to not only improve QoL, 
but also reduce the need for biliary diversion and subsequent liver failure and liver 
transplantation. 
The doses selected for the A4250-005 Phase 3 study, 40 and 120 µg/kg/day, were based on the 
efficacy and safety data generated from patients with PFIC (n=10 + 3 re-entered) and 

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supporting data from all patients (n=20 + 4 re-entered) in the five dose groups dosed in the 
A4250-003 Phase 2 study. Improvements of serum bile acids and pruritus were observed with 
doses from 30 to 100 µg/kg/day with a dose-related trend. The best dose response in all patients 
was at the 60 µg/kg/day for serum bile acids and 100 µg/kg/day for pruritus. The best dose 
response in the PFIC subgroup was at 30 µg/kg/day for both serum bile acids and pruritus. 
Patients with PFIC responded well to the doses given from 30 to 200 µg/kg/day; however, a 
clear dose relationship could not be established in order to select a single dose for the A4250- 
005 study. As efficacy was observed at both low and high doses, 40 and 120 µg/kg/day were 
considered to be the most optimal for the A4250-005 study. Both low and high doses, 
40 µg/kg/day 2 and 120 µg/kg/day, will be used in this study.  Patients not tolerating the 
120 µg/kg/day dose may down-titrate to the lower dose after a minimum of 1 week on the high 
dose. The patient should return to the higher dose as soon as deemed appropriate by the 
investigator. More than one upward dose titration (from 40 µg/kg/day directly to 120 
µg/kg/day) for the same event is not recommended. Any dose titration should be done in 
consultation with the sponsor Medical Monitor or designee. 
Rationale for patient selection: 
Cohort 1: Patients in Cohort 1 are children with PFIC Types 1 and 2 who have completed study 
A4250-005 (PEDFIC 1) and will be enrolled to collect data on the efficacy (impact on pruritus 
and clinical laboratory parameters) and safety of long-term administration of A4250. 
Cohort 2: Cohort 2 will enroll patients with PFIC who (1) have both pruritus and elevated 
serum bile acids but are otherwise not eligible to enroll in A4250-005 (PEDFIC 1) or (2) 
patients who are eligible for enrolment in A4250-005 after recruitment of study A4250-005 
has been completed. These patients will be enrolled to collect data on the efficacy (impact on 
pruritus and clinical laboratory parameters) and safety of long-term administration of A4250. 
Rationale for enrolling patients with PFIC types other than 1 and 2 
The purpose of enrolling patients with other types of PFIC in Cohort 2 is to allow for the 
collection of preliminary data in patients who are not eligible for the pivotal study A4250-005, 
but for whom there exists a reasonable potential to benefit from an IBAT therapy. The data 
obtained may inform both the safety of A4250 and future potential studies in these patient 
populations. 
High levels of bile acids are toxic to the liver. A4250 interrupts the enterohepatic bile acid 
circulation which in turn should lower the bile acid pool. A4250 therefore has the potential to 
ameliorate the effects of bile acid elevation in several conditions where bile acids are thought 
to play a pathological role. These include intrahepatic cholestatic diseases other than PFIC 
types 1 and 2. In the Albireo Phase 2 study A4250-003, 24 paediatric patients diagnosed with 
 
2 As of Protocol Amendment 6.1 UK, patients entering Cohort 2 will start treatment at 40 µg/kg/day with 
the possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus based 
on investigator judgment. 

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
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Amendment 6.1 UK, 11 February 2022
24
intrahepatic cholestasis were administered A4250 daily for up to 4 weeks. Of the PFIC patients 
included, one patient had PFIC-1, seven had PFIC-2, two had PFIC-3 and one had intrahepatic 
cholestasis associated with microvillus atrophy. Following treatment with A4250, the patients 
with PFIC-3 and microvillus atrophy experienced reductions in their serum bile acid levels and 
improvements in both their pruritus and sleep scores. These data suggest that A4250 has the 
potential to impact outcomes in cholestatic diseases other than PFIC types 1 and 2, and support 
the rationale for its investigation in patients with these conditions. With respect to safety,
A4250 has demonstrated a favourable profile in both healthy volunteers and paediatric patients 
with pruritic intrahepatic cholestatic diseases, at doses well above those currently under 
investigation in studies A4250-005 and A4250-008. As such, there are no specific safety risks
or concerns anticipated in the expanded PFIC populations, when A4250 is administered at the 
current doses in this study. 
This study will be conducted in compliance with the protocol and with the International
Council for Harmonisation (ICH) guidelines on Good Clinical Practice (GCP). 
5.3.1
Risk/Benefit
Following review of the available safety and efficacy data, A4250 (INN odevixibat) has been 
approved by the EMA and the US FDA for use in patients with PFIC. A4250 has been 
evaluated in 6 Albireo-sponsored clinical studies: a double-blind placebo-controlled study in 
healthy volunteers, a single-dose ADME study, a single-dose food interaction study, a DDI 
study, a Phase 2 study in children with cholestatic pruritus, and a Phase 3 study in children with 
PFIC. In addition, an investigator-sponsored study has been conducted in patients with PBC. 
A total of 258 subjects/patients have been exposed to A4250. Healthy subjects have been 
exposed to up to 10 mg as a single dose and up to 3 mg daily as part of a multiple-dose 
evaluation. Children with cholestatic liver disease have been treated with up to 200 µg/kg/day 
for 4 weeks. In the Phase 3 study in children with PFIC, children have been treated with A4250 
for 24 weeks at a dose of 40 
Two SAEs were reported in the 
Phase 2 study and 4 SAEs were reported in 3 patients receiving A4250 in the Phase 3 study; 
all were judged by the investigator to be not related to the study drug.
Patients with cholestatic liver diseases suffer from excess bile acids in the liver resulting in 
tissue damage. A commonly used treatment in these patients is bile diversion surgery, whereby 
approximately 50% to 100% of the enterohepatic circulation of bile acids is interrupted. 
Inhibition of IBAT with A4250, thereby interrupting the enterohepatic circulation of bile acids, 
is therefore a potential medical alternative to surgery which could be of benefit to these patients 
if shown to be effective and safe. Data from the Phase 2 and 3 studies showed efficacy of 
A4250 in reducing serum bile acid concentrations and pruritus in such patients. 
Based on the mode of action of A4250, an IBAT inhibitor, loose stools or diarrhea, and 
abdominal pain are expected AEs. Non-serious diarrhea and abdominal pain were reported in 
healthy volunteers and in the investigator-initiated PBC study and in one patient following

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
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Amendment 6.1 UK, 11 February 2022 
25 
 
 
 
single dose, but none following multiple dosing in the Phase 2 study in pediatric patients with 
pruritic cholestatic liver disease. Non-serious diarrhea, vomiting, and abdominal pain were 
observed in the Phase 3 study in pediatric patients with PFIC. 
A4250 taken once daily (QD) at doses up to 200 µg/kg/day, as tested in the Phase 2 study 
A4250-003, and up to 120 µg/kg/day as evaluated in the Phase 3 study A4250-005, was overall 
well tolerated. Gastrointestinal (GI) treatment-emergent adverse events (TEAEs) including 
abdominal pain, abdominal discomfort and diarrhea or loose stool, were associated in time with 
the onset of the treatment effect of A4250. In general, these AEs were mild to moderate in 
nature and self-limiting, did not require treatment intervention and were not linked to the degree 
of reduction of serum bile acid or a rapid reduction in serum bile acid levels. 
5.3.2 
Risk/Benefit of Receiving COVID-19 Vaccine during Trial Participation 
Nonclinical: The risk of immunotoxicity has been evaluated based on results from standard 
toxicity studies. No obvious signs in related organs have been detected in response to A4250 
treatment (e.g., changes in thymus, spleen, lymph nodes, or bone marrow). Altered hematology 
and incidence of infection have not been detected. Neither IBAT specifically nor bile acids in 
general are expected to perturb immunological responses. No signs of immunological reactions 
have been seen in clinical trials thus far. Based on the outcome from the standard toxicity 
studies and the general profile and mechanism of action of A4250, the risk of immunotoxicity 
has been considered low and dedicated immunotoxicity studies have not been performed. 
Clinical: Based on an integrated safety analysis of data from the completed A4250-005 study 
and the ongoing open-label extension study A4250-008 in patients with PFIC treated for 48 
weeks or longer with A4250, no safety signal or trends relative to immunological reactions 
have been reported. This is consistent with the mechanism of action of A4250 and the non- 
clinical data. No trends or safety signals were observed as it relates to hematology including 
white blood cell count, differential counts and C-reactive protein. No events of allergic 
reactions to A4250 or its excipients have been reported. 
The overall incidence of infections was 49% (41 of 84 patients) with upper respiratory tract 
infection being the most common type of infection reported in 24% of patients. Other 
commonly reported infections were 
nasopharyngitis, 
otitis media, influenza, 
and 
gastroenteritis, reported in 11%, 7%, 6%, and 6%, respectively, of patients in the PFIC Phase 
3 studies. 
The risk of an undesirable outcome after receiving the COVID-19 vaccine while treated with 
A4250 has not been studied and is unknown. 

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
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Amendment 6.1 UK, 11 February 2022
26
6
STUDY OBJECTIVES
6.1
Primary Objectives
Primary Objective (Cohort 1)
To demonstrate a sustained effect of A4250 on serum bile acids and pruritus in children with 
PFIC Types 1 and 2. 
Primary Objective (Cohort 2)
To evaluate the effect of A4250 on serum bile acids and pruritus in patients with PFIC who 
either (1) do not meet eligibility criteria for Study A4250-005 (PEDFIC 1) or (2) who do 
meet the eligibility criteria for Study A4250-005 after recruitment of Study A4250-005 has 
been completed. 
6.2
Secondary Objectives
Secondary Objectives (Cohorts 1 and 2)
The secondary objectives of this study are:
To evaluate the long-term safety and tolerability of repeated daily doses of A4250
 
To evaluate the effect of A4250 on growth 
To evaluate the effect of A4250 on biliary diversion and/or liver transplantation
To evaluate the effect of A4250 on biochemical markers of cholestasis and liver disease

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Confidential
Amendment 6.1 UK, 11 February 2022
27
7
INVESTIGATIONAL PLAN
7.1
Overall Study Design and Plan
7.1.1
Description
This is a Phase 3, multi-center, open-label extension study to investigate the long-term efficacy 
and safety of a 120 µg/kg daily dose of A4250 in patients with PFIC, including episodic forms 
also referred to as BRIC. Cohort 1 will consist of children with PFIC Types 1 and 2 who have 
participated in Study A4250-005. Cohort 2 will consist of approximately 60 patients with any 
type of PFIC who have elevated serum bile acids and cholestatic pruritus and who either (1) do 
not meet eligibility criteria for Study A4250-005 (PEDFIC 1) or (2) are eligible for enrolment
in A4250-005 after recruitment of study A4250-005 has been completed. Up to 40 patients
post biliary diversion surgery are allowed to participate in Cohort 2. 
The study includes a 72-week Treatment Period and a 4-week Follow-up Period. Patients who 
wish to continue receiving A4250 after 72 weeks will have the option to remain on treatment 
in an extension period with visits every 16 weeks until the drug is commercially available, 
provided continued use is supported by the risk-benefit profile and the subject has not been 
previously withdrawn or discontinued from the study. In that case the 4-week Follow-up 
Period will not occur.
The study data will be reviewed periodically (approximately on a quarterly basis) by a Data 
Safety and Monitoring Board (DSMB) until the last patient reaches 72 weeks. 
Eligible patients will be enrolled into this open-label extension study and treated with a daily 
dose of 40 µg/kg/day3 or 120 µg/kg/day of A4250 for 72 weeks, or 40 µg/kg/day for the first 
12 weeks followed by 120 µg/kg/day for the remaining 60 weeks3. Patients not tolerating the 
120 µg/kg/day dose after a minimum of 1 week for reasons other than new liver findings and 
severe diarrhea, as described in Section 10.2.2, will have the option to down-titrate to a lower 
dose (40 µg/kg/day). The patient should return to the higher dose as soon as deemed 
appropriate by the investigator. More than one upward dose titration (from 40 µg/kg/day
directly to 120 µg/kg/day) for the same event is not recommended. Any dose titration should 
be done in consultation with the sponsor Medical Monitor or designee.
Patients participating in the optional extension period will continue on a daily dose of 
40 µg/kg/day or 120 µg/kg/day of A4250 with the option to down-titrate to a lower dose 
(40 µg/kg/day). 
Patients in Cohort 2 will go through a screening period consisting of:
Visit S-1: Screening Visit 1 (Days -56 to -35). 
3 As of Protocol Amendment 6.1 UK, patients entering Cohort 2 will start treatment at 40 µg/kg/day with 
the possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus based 
on investigator judgment.

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Confidential
Amendment 6.1 UK, 11 February 2022
28
Visit S-2: Screening Visit 2 (Days -28 to -7)
Patients not meeting eligibility criteria may be re-screened after consultation with the Medical 
Monitor. Patients not fulfilling inclusion/exclusion criteria after 3 attempts are not allowed to 
rescreen.
Patients will have a minimum of 12 visits at the study site and 6 scheduled telephone contacts 
(see Figure 1 and Figure 2) as follows:
Visit 1: Screening/Inclusion Visit (Day 1; coincides with Visit 9 in Study A4250-005 for 
patients in Cohort 1) 
Visit 2: Week 4 
Telephone contact 1: Week 8 
Visit 3: Week 12
Telephone contact 2: Week 18
Visit 4: Week 22
Visit 5: Week 24
Telephone contact 3: Week 30
Visit 6: Week 36
Telephone contact 4: Week 42
Visit 7: Week 46
Visit 8: Week 48
Telephone contact 5: Week 54
Visit 9: Week 60
Telephone contact 6: Week 66
Visit 10: Week 70
Visit 11: Week 72/Optional extension period
Visit 12: Follow-up Visit; Week 76 (for those not participating in optional extension period) 
Optional extension period visits every 16 weeks; Week 88 and onwards 
Additional clinic visits may be required for patients who need direct site assistance including, 
but not limited to, AE monitoring for safety maintenance.
Informed consent must be obtained prior to performing any study procedures. After signing 
the informed consent form (ICF), patients will be evaluated for study eligibility and considered 
enrolled in the study. For Cohort 1, patients who completed 24 weeks, or who withdrew after 
a minimum of 12 weeks of treatment with A4250 due to intolerable symptoms in Study

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.1 UK, 11 February 2022 
29 
 
 
 
A4250-005 and meeting all inclusion criteria and no exclusion criteria are eligible for this 
study. Patients who withdraw from A4250-005 due to a study drug related AE will not be 
eligible. For Cohort 2, patients meeting all inclusion criteria and no exclusion criteria are 
eligible for this study. 
Patients/caregivers will be instructed to fill in the electronic diary (eDiary) every morning and 
evening for the first 24 weeks (Visit 1 through Visit 5) and the 21 days before each clinic visit 
thereafter (Visit 6 through Visit 12). In addition, Cohort 2 patients/caregivers will be instructed 
to fill in the eDiary during the screening period. Patients participating in the optional extension 
period will stop eDiary entries at Visit 11. The eDiary will include patient-reported outcome 
(PRO) and observer-reported outcome (ObsRO) items for evaluation of itching (PRO), 
scratching (ObsRO), and sleep disturbance (PRO and ObsRO). Observer-reported outcomes 
in patients of all ages will be recorded by a caregiver. If possible, the same caregiver will 
complete the ObsRO items throughout the study. Additionally, caregivers will be requested to 
report in the diary the time that study drug was administered during the Treatment Period. 
The patient will return to the clinic after 4 weeks and 12 weeks and thereafter every 10 to 
12 weeks for follow-up measurements. Between the clinic visits there will be a telephone 
contact with the patient/caregiver to report AEs. 
At Visit 11, patients will be offered the choice to continue receiving A4250 treatment in an 
optional extension period. In the extension period the patient will continue to receive A4250 
at the same dose as at the end of the 72-week treatment period, returning to clinic every 16 
weeks until the drug is commercially available, provided continued use is supported by the 
risk-benefit profile and the subject has not been previously withdrawn or discontinued from 
study. 
If the patient is prematurely withdrawn from the study, all assessments scheduled for Visit 11 
will be performed at the time the patient withdraws. If a patient participating in the optional 
extension study withdraws prior to commercial drug availability, all assessments scheduled for 
the optional Extension Period End of Treatment visit will be performed. 
If a liver biopsy is performed according to the local regulations or standard of care at any time 
during A4250-008, the biopsy results should be recorded in the electronic case report form 
(eCRF). If the patient had liver biopsy results collected in study A4250-005 or prior to Week 
24 in study A4250-008, the patient will be asked to consent to a follow-up liver biopsy, if 
allowed per local regulations, at Visit 11, unless 2 prior liver biopsy results have been collected 
with at least 1 year between biopsies. Liver biopsies will not be performed in Spain. 
For those not participating in the optional extension period, Visit 12 will take place 28 days 
after Visit 11. All patients prematurely withdrawn will have this visit 28 days after the last 
dose of study drug for AE and other follow-up. 
If a patient discontinues prior to Week 72, additional telephone contacts will be made every 
3 months after the Follow-up Visit (Visit 12) up to Week 72 to gather whether or not the patient 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.1 UK, 11 February 2022 
30 
 
 
 
has had biliary diversion or liver transplantation, and if TEAEs ongoing at the time of 
discontinuation have resolved. The telephone calls will take place up until 72 weeks even if the 
patient has biliary diversion or liver transplant. 
Details of study assessments are provided in the schedule of assessments (Table 1 and Table 2). 
Figure 1    Study Design up to Protocol Amendment 5.1 UK 
 
QD: once daily; T: telephone contact; V: study visit; VS: Visit Screening 
Note: Visit 1 coincides with Visit 9 of Study A4250-005. Patients who are not tolerating the 120 µg/kg/day dose 
may be down-titrated to the 40 µg/kg/day dose following a minimum of 1 week of treatment. The patient can 
return to the higher dose as soon as deemed appropriate. 
This figure is only applicable to Cohort 2 up to Protocol Amendment 5.1 UK. Figure 2 presents the study design 
for Cohort 2 as of Protocol Amendment 6.1 UK. 
Figure 2    Study Design for Cohort 2 as of Protocol Amendment 6.1 UK 
 
QD: once daily; T: telephone contact; V: study visit; VS: Visit Screening 
Note: As of Protocol Amendment 6.1 UK, patients entering Cohort 2 will start treatment at 40 µg/kg/day with the 
possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus based on 
investigator judgment. The patient can return to the lower dose if the 120 µg/kg/day dose is not tolerated following 
a minimum of 1 week of treatment. 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
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Amendment 6.1 UK, 11 February 2022 
31 
 
 
 
End of Study 
The end of the study is defined as follows: 
a) End of study in one country: last patient last visit (LPLV) and sites are closed. 
b) End of study globally: LPLV globally and all sites closed 
7.1.2 
Schedule of Assessments 
The schedule of assessments for the screening period through the follow-up period is presented 
in Table 1 and the schedule of assessments for the optional extension period is presented in 
Table 2. For information on blood volumes, please see Appendix 7. 

 
A4250-IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 - Protocol A4250-008 
Table 1 
Schedule of Assessments (Screening Period through Follow-up Period) 
 
Screening 
Period (Cohort 
2 only) 
Treatment Period 
Follow- 
up 
I
Period" 
Study Activity 
Screen!ng/ I 
4 
I 
12  I 
22  I 
24  I 
36  I 
46  I 
48  I 
60  I 
70  I 
72 
I 76 weeks 
IncVl iton 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
ISi 
Study Days 
-56- 
(±window) 
(-35) 
±2 
-28- 
(-7) 
±2 
1 
28 
84 
154 
168 
252 
322 
336 
420 
490 
504 (±7) 
I 532 (±7) 
(±5) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
I 
I 
I 
I 
I 
I 
I 
I 
I 
I 
Visit 
Clinic Visits 
Visit 
Visit 
Visit I" 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
11/EOT /Start of I 
Visit 12c 
S-1 
S-2 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Optional 
Extension Period' 
Informed consent 
X 
xct 
Inclusion/exclusion 
criteria 
X 
X 
Demography/Medical 
and Surgical History 
X 
Concomitant 
medicatione 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Physical examinationr 
X 
X 
X 
X 
X 
X 
Skin examination 
X 
X 
X 
X 
X 
X 
X 
Vital signss 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
eDiary: itching, 
scratching, and sleep 
scoresh 
Daily diary entry 
For 21 days before each clinic visit for Visit 6 through Visit 12 
 
 
Confidential 
32 
Amendment 6.1 UK, 11 February 2022 

A4250-IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 - Protocol A4250-008 
Confidential 
Amendment 6.1 UK, 11 February 2022 
34 
 
 
 
Screening 
Period (Cohort 
2 only) 
Treatment Period 
Follow- 
up 
Period" 
Study Activity 
Screen!ng/ I 
4 
I 
12  I 
22  I 
24  I 
36  I 
46  I 
48  I 
60  I 
70  I 
72 
I  76 weeks 
IncVl iton 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
ISi 
-56- 
-28- 
1 
28 
84 
154 
168 
252 
322 
336 
420 
490 
504 (±7) 
I 532 (±7) 
(±5) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
I 
I 
I 
I 
I 
I 
I 
Study Days 
(-35) 
(±window) 
±2 
(-7) 
±2 
Visit 
Clinic Visits 
Visit 
Visit 
Visit la 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
11/EOT /Start of 
I  Visit 12c 
S-1 
S-2 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Optmnal 
Extension Period' 
Fibroscan (where 
available) 
X 
X 
X 
X 
QoL questionnaire 
(PedsQL) 
X 
X 
X 
X 
Patient/Caregiver/Clin 
ician Patient Global 
Impression of Change 
X' 
X 
X 
X 
X 
X 
Patient/Caregiver/Clin 
ician Patient Global 
X 
X 
X 
X 
X 
X 
Impression of 
I 
I 
I 
I 
I 
I 
I 
I
 
Symptoms 
Pregnancy test1 
xi 
X 
xi 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Telephone contact 
Patients will be contacted via telephone for adverse event monitoring at Weeks 8, 18, 30, 42, 54, and 66 
Liver biopsy"' 
X 
Study drug dispensed11 
X 
X 
X 
X 
X 
X 
X 
X' 

A4250-IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 - Protocol A4250-008 
Confidential 
Amendment 6.1 UK, 11 February 2022 
35 
 
 
 
Screening 
Period (Cohort 
2 only) 
Treatment Period 
Follow­ 
up 
Period" 
Study Activity 
Screening/ 
Inclusion 
Visit 
4 
weeks 
12 
weeks 
22 
weeks 
24 
weeks 
36 
weeks 
46 
weeks 
48 
weeks 
60 
weeks 
70 
weeks 
I 
72 
weeks 
76 weeks 
Study Days 
(±window) 
-56- 
(-35) 
±2 
-28- 
(-7) 
±2 
1 
28 
(±5) 
84 
(±7) 
154 
(±7) 
168 
(±7) 
252 
(±7) 
322 
(±7) 
336 
(±7) 
420 
(±7) 
490 
(±7) 
504 (±7) 
532 (±7) 
Clinic Visits 
Visit 
S-1 
Visit 
S-2 
Visit la 
Visit 
Visit 
Visit 
Visit 
I 
 Visit 
I 
 Visit 
Visit 
Visit 
Visit 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Visit 
11/EOT /Start of I 
Optional 
Extension Period' 
Visit 12c 
Adverse events0P 
Continuous collection 
Study drug 
compliance evaluated 
X 
xq 
X 
xq 
X 
X 
xq 
eCRF: electronic case report form; eDiary: electronic diary; EOT: end of treatment; p-C4: plasma 7a Hydroxy 4-cholesten-3-one; PedsQL: pediatric quality of life; QoL: 
quality of life. 
a 
For patients in Cohort I, Visit I coincides with Visit 9 in Study A4250-005. Assessments that have been performed at Visit 9 during Study A4250-005 will not be 
repeated. 
b 
Assessments must also be performed at the time a patient is prematurely withdrawn from the study. If a patient discontinues prior to week 72, additional phone contact 
will be made every 3 months up to a total study participation of72 weeks to assess if the patient has had biliary diversion or liver transplantation. 
c 
Assessments must be performed 28 days following the final dose of study drug. 
d 
Only for Cohort 1. 
e 
Includes current medications. 
f 
A complete physical exam will be performed at Visits S-1, 1, 3, 5, 8, and 11/EOT. 
g 
Includes blood pressure, pulse, respiratory rate, temperature, height/length (using a certified stadiometer), mid-arm circumference (3 repeat measures), and body weight 
(using a certified weight scale). Body mass index will be calculated. 

A4250-IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 - Protocol A4250-008 
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Amendment 6.1 UK, 11 February 2022 
36 
 
 
 
Screening 
I 
Period (Cohort 
2 only) 
 
Treatment Period 
Follow­ 
up 
Period" 
Study Activity 
Screen!ng/ I 
IncVl iton 
ISi 
4 
I 
weeks 
12  I 
weeks 
22  I 
weeks 
24  I 
weeks 
36  I 
weeks 
46  I 
weeks 
48  I 
weeks 
60  I 
weeks 
70 
weeks 
72 
weeks 
76 weeks 
Study Days 
(±window) 
-56- 
(-35) 
±2  I 
-28- 
(-7) 
±2 
1 
I 
28 
(±5)  I 
84 
(±7) 
154 
(±7) 
168 
(±7)  I 
252 
(±7)  I 
322 
(±7)  I 
336 
(±7)  I 
420 
(±7) 
490 
(±7) 
504 (±7) 
532 (±7) 
Clinic Visits 
Visit 
S-1 
Visit 
Visit la 
S-2 
Visit 
2 
Visit 
3 
Visit 
4 
Visit 
5 
Visit 
6 
Visit 
7 
Visit 
8 
Visit 
9 
Visit 
10 
Visit 
11/EOTb/Start of 
Optional 
Extension Period' 
Visit 12c 
h 
Itching, scratching, and sleep will be assessed via an eDiary (issued with any necessary training to patients/caregivers at Visit I). Patients/caregivers will be instructed 
to fill in the eDiary every morning and evening for the first 24 weeks and the last 21 days before all the remaining visits to the clinic. There will be no interruption 
between Visits 11 and 12. Patients participating in the extension period will stop eDiary entries at Visit 11. 
See Table 4 for detailed parameters. 
j 
Patients will fast (only water intake is permissible) for at least 4 hours prior to the collection of samples for serum bile acids and vitamin A. Exceptions can be made for 
infants, less than 12 months of age, if unable to fast for the entire 4 hours. 
k 
Autotaxin and p-C4 samples will not be collected for patients :S 10 kg. 
For girls who have reached menarche. Serum test will be performed at Visit S-1 for Cohort 2 only and Visit I (for Cohort I only); urine test will be performed at all 
other visits. If a urine pregnancy test is positive, a serum pregnancy test should be performed to confirm the pregnancy. 
m 
If a liver biopsy is performed at any time during A4250-008 according to the local regulations or standard of care, the biopsy results should be recorded in the eCRF. If 
the patient has liver biopsy results collected in study A4250-005 or prior to Week 24 in study A4250-008, the patient will be asked to consent to a follow up liver 
biopsy, if allowed per local regulations, at Visit 11 unless 2 prior liver biopsy results have been collected with at least l year between biopsies. Liver biopsies will not 
be performed in Spain. 
n 
Study drug will be taken once daily from Day I through Day 504 as described in Section 8.2. 
o 
Adverse event information will be collected from the time of signing of the informed consent form to study discontinuation. 
p 
For hepatic adverse events and/or hepatic decompensation, a PK sample should be collected as close to the onset of the event as possible (PK samples not required 
during screening period). 
q 
Dosage form acceptability questions will be asked of the caregiver and/or patient at Visits 3, 6, and 11. 

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37 
 
 
 
Screening 
Period (Cohort 
2 only) 
Treatment Period 
Follow­ 
up 
Period" 
Study Activity 
Screening/ 
Inclusion 
Visit 
4 
weeks 
12 
weeks 
22 
weeks 
24 
weeks 
36 
weeks 
46 
weeks 
48 
weeks 
60 
weeks 
70 
weeks 
I 
72 
weeks 
76 weeks 
Study Days 
(±window) 
-56- 
(-35) 
-28- 
(-7) 
±2 
1 
28 
(±5) 
84 
(±7) 
154 
(±7) 
168 
(±7) 
252 
(±7) 
322 
(±7) 
336 
(±7) 
420 
(±7) 
490 
(±7) 
504 (±7) 
532 (±7) 
±2 
Clinic Visits 
Visit 
S-1 
Visit 
S-2 
Visit la 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Visit 
11/EOT /Start of I 
Optional 
Extension Period' 
Visit 12c 
r 
Patient/Caregiver/Clinician Patient Global Impression of Change not applicable for Cohort 2. 
s 
Patients who wish to continue receiving A4250 after 72 weeks, will have the option to remain on treatment in an optional extension period until the drug is 
commercially available, provided continued use is supported by the risk-benefit profile and the patient has not been previously withdrawn or discontinued from study. 
Dispensation only for patients moving into the optional extension period. 
u 
Only for patients who stop treatment at 72 weeks. 

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Table 2 
Schedule of Assessments (Optional Extension Period) 
 
Extension Period 
Extension Period EOT 
Study Activity 
Every 16 weeks 
Study Days (±window) 
Every 112 days (±7) 
Concomitant medicationa 
X 
X 
Vital signsb 
X 
X 
Clinical chemistryc 
X 
X 
Serum bile acidsd 
X 
X 
Vitamins Ad, E, and 25-hydroxy vitamin D 
X 
X 
International normalized ratio 
X 
X 
Urine pregnancye 
X 
X 
Adverse eventsf 
X 
X 
Study drug compliance evaluated 
X 
X 
Study drug dispensedg 
X 
QoL questionnaire (PedsQL) 
X 
X 
Patient/Caregiver/Clinician Patient Global 
Impression of Change 
X 
X 
Patient/Caregiver/Clinician Patient Global 
Impression of Symptoms 
X 
X 
a Includes current medications. 
b Includes blood pressure, pulse, respiratory rate, temperature, height/length (using a certified stadiometer), mid-arm 
circumference (3 repeat measures), and body weight (using a certified weight scale). Body mass index will be calculated. 
c See Table 4 for detailed parameters. 
d Patients will fast (only water intake is permissible) for at least 4 hours prior to the collection of samples for serum bile 
acids and vitamin A. 
e For girls who have reached menarche. 
f For hepatic adverse events and/or liver decompensation, a PK sample should be collected as close to the onset of the 
event as possible 
g Study drug will be taken once daily throughout the extension period. 
7.1.3 
Study Procedures and Assessments 
When the COVID-19 pandemic makes it challenging for a patient to attend a visit at the study 
center and where applicable country and local regulations and infrastructure allow, routine 
assessments may be performed outside of the study center (e.g., the patient’s home) by a trained 
healthcare professional at all timepoints following the Inclusion Visit (Visit 1). These 
assessments can include the following: vital signs, height and weight, mid-arm circumference, 
body assessement, blood draws, urine collection, and urine pregnancy test. All laboratory 
samples should be sent to the central laboratory; an exception is for situations related to the 
COVID-19 pandemic if central laboratory assessments are not possible, then a local laboratory 
may be used. These local laboratory results must be sent to the site for review by the 
investigator and submitted to iRIS (ICON Results Integration Services). Collection of other 

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visit requirements, e.g., concomitant medication and AE collection associated with visits
outside of the clinic will be collected by qualified site staff through verbal contact with the 
patient.
For any study visit, the study physician (or delegate) must, at a minimum, verbally contact the 
patient within the expected window for each study visit to collect relevant safety information 
(including, but not limited to, AEs, concomitant medications, hospitalizations/procedures, and 
vital status). Any missed assessment due to a study visit being performed outside of the study 
center will be considered a protocol deviation.
7.1.3.1
Screening Period (Days -56 to 0) (For Cohort 2 only)
If the screening period is expected to be prolonged due to COVID-19 related issues, site follow- 
up with the medical monitor and investigator is required to determine if the screening period
can be extended for another two weeks. Determination will be assessed on a case-by-case basis. 
During this allowed two-week extension period, it is anticipated that no additional testing and 
assessments will be required. If the screening period is extended beyond two weeks, additional 
assessments, including but not limited to safety labs, will be required.
Day -56 to Day -35/Clinic Visit S-1 
Cohort 2 patients will undergo a Screening Visit up to 56 days prior to the planned first day of 
study treatment. Screening procedures and assessments are as follows:
Obtain written informed consent
Assess inclusion/exclusion criteria (Section 7.2) 
Record demographics
Document concomitant medications
Medical and surgical history (date of diagnosis of PFIC Type, prior investigational 
medications for PFIC, historical liver function test [LFT] values, any surgery performed,
any other diagnosis, and historical liver biopsy data) 
For patients with episodic forms of PFIC (i.e., BRIC), collect information on frequency, 
duration, and severity of flares within the last 6 months at a minimum, and within the last 
5 years, if possible. If available, historical data on serum bile acid levels and pruritus should 
be collected
Collect, if available, past confirmatory clinical genetic laboratory report for PFIC, 
including BRIC, type and send to central reader for review. If a historical report is 
equivocal, unavailable, or unobtainable, a blood sample for clinical genetic testing will be 
collected to determine eligibility (Section 10.2.4) 
Physical examination (Section 10.2.5) and vital signs (Section 10.2.6) 
 
Skin examination (Section 10.2.5) 

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eDiary training and compliance requirements; caregivers and/or patients begin daily 
recording of pruritus using the eDiary (Appendix 2) 
Clinical chemistry (Section 10.2.1) 
Serum bile acids (Section 9.2.1) 
Serum pregnancy test for girls who have reached menarche. Please see Appendix 6 for 
contraceptive requirements
AE monitoring
Day -28 to Day -7/Clinic Visit S-2 
A second Screening Visit will be performed for patients in Cohort 2. Screening procedures 
and assessments are as follows:
Review concomitant medications 
Vital signs (Section 10.2.6) 
Albireo PRO/ObsRO eDiary review for compliance
Serum bile acids (Section 9.2.1)
International normalized ratio (INR)
Urine pregnancy test for girls of who have reached menarche
 
AE monitoring 
Clinical chemistry retest (if applicable)
7.1.3.2
Treatment Period 
Study Day 1/Visit 1
For Cohort 1, patients will undergo a Screening/Inclusion Visit that coincides with Visit 9 of 
Study A4250-005. 
For Cohort 1: Obtain written informed consent
For Cohort 2: Albireo PRO/ObsRO eDiary review for compliance and eligibility criteria (see 
Inclusion Criteria 4 [Cohort 2, excluding BRIC], Section 7.2.1).
The following procedures will be conducted for both cohorts:
Assess inclusion/exclusion criteria (Section 7.2) 
Document concomitant medications
Physical examination (Section 10.2.5) and vital signs (Section 10.2.6) 
 
Skin examination (Section 10.2.5) 

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Albireo PRO/ObsRO eDiary training, compliance requirements, and instructions to 
continue recording of pruritus (Appendix 2) 
Clinical chemistry, hematology, and urinalysis (Section 10.2.1) 
Serum bile acids (Section 9.2.1) 
p-C4 and autotaxin
Alfa-fetoprotein (AFP)
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1) 
 
Abdominal ultrasound (Section 10.2.7) 
Fibroscan, where available (Section 9.2.8) 
Administer QoL (Pediatric Quality of Life Inventory [PedsQL]) questionnaire
Serum pregnancy test for girls who have reached menarche (only for patients in Cohort 1).
Please see Appendix 6 for contraceptive requirements
Patient/caregiver/clinician complete the patient global impression of symptoms (PGIS) and 
the patient global impression of change (PGIC) 
AE monitoring
Study drug is dispensed
Week 4/Visit 2 
The following procedures and assessments will be conducted: 
Document concomitant medications
Vital signs (Section 10.2.6) 
Skin examination (Section 10.2.5) 
Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry and hematology (Section 10.2.1)
INR
Serum bile acids (Section 9.2.1) 
 
p-C4 and autotaxin 
Patient/caregiver/clinician complete the PGIS and the PGIC
Urine pregnancy test for girls who have reached menarche
AE monitoring
Evaluation of study drug compliance

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Study drug is dispensed
Week 8/Telephone contact 1 
A study nurse will contact patients via telephone for AE monitoring 4 weeks after Visit 2,
at Week 8
Week 12/Visit 3 
As of Protocol Amendment 6.1 UK, patients entering Cohort 2 will start treatment at 
40 µg/kg/day with the possibility to dose escalate to 120 µg/kg/day after 12 weeks (Visit 3) if 
there is no improvement in pruritus based on investigator judgment. 
The following procedures and assessments will be conducted (all patients): 
Document concomitant medications
Physical examination (Section 10.2.5) and vital signs (Section 10.2.6) 
 
Skin examination (Section 10.2.5) 
Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry and hematology (Section 10.2.1) 
INR
Serum bile acids (Section 9.2.1) 
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1) 
Patient/caregiver/clinician complete the PGIS and the PGIC
Urine pregnancy test for girls who have reached menarche
AE monitoring
Evaluation of study drug compliance; dosage form acceptability questions will be asked of 
the caregiver and/or patient
Study drug is dispensed

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Week 18/Telephone contact 2 
A study nurse will contact patients via telephone for AE monitoring 6 weeks after Visit 3,
at Week 18
Weeks 22 and 46/Visits 4 and 7 
The following procedures and assessments will be conducted: 
Document concomitant medications
Vital signs (Section 10.2.6) 
Albireo PRO/ObsRO eDiary review for compliance
INR
Serum bile acids (Section 9.2.1) 
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1) 
Urine pregnancy test for girls who have reached menarche
 
AE monitoring 
Weeks 24 and 48/Visits 5 and 8 
The following procedures and assessments will be conducted:
Document concomitant medications
Skin examination (Section 10.2.5) 
Physical examination (Section 10.2.5) and vital signs (Section 10.2.6)
Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry, hematology, and urinalysis (Section 10.2.1) 
Serum bile acids (Section 9.2.1)
p-C4 and autotaxin 
AFP
Abdominal ultrasound (Section 10.2.7) 
Fibroscan, where available (Section 9.2.8) 
Administer PedsQL questionnaire
Patient/caregiver/clinician complete the PGIS and the PGIC
Urine pregnancy test for girls who have reached menarche
AE monitoring
Evaluation of study drug compliance

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Study drug is dispensed
Weeks 30 and 54/Telephone contacts 3 and 5 
A study nurse will contact patients via telephone for AE monitoring 6 weeks after Visits 5 
and 8, at Weeks 30 and 54, respectively 
Weeks 36 and 60/Visits 6 and 9 
The following procedures and assessments will be conducted:
Document concomitant medications 
Vital signs (Section 10.2.6) 
Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry and hematology (Section 10.2.1) 
INR
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1) 
Serum bile acids (Section 9.2.1) 
Urine pregnancy test for girls who have reached menarche
 
AE monitoring 
Evaluation of study drug compliance; dosage form acceptability questions will be asked of 
the caregiver and/or patient (only at Visit 6) 
Study drug is dispensed
Weeks 42 and 66/Telephone contacts 4 and 6 
A study nurse will contact patients via telephone for AE monitoring 6 weeks after Visits 6 
and 9, at Weeks 42 and 66, respectively 
Week 70/Visit 10
The following procedures and assessments will be conducted: 
Document concomitant medications
Vital signs (Section 10.2.6)
Albireo PRO/ObsRO eDiary review for compliance
Serum bile acids (Section 9.2.1)
INR
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1) 
Urine pregnancy test for girls who have reached menarche

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AE monitoring
7.1.3.3
End of Treatment/Early Termination/Start of Optional Extension Period 
Week 72/Visit 11
The last dose of study drug will be administered in the morning the day before the visit and the 
following assessments will be performed:
Document concomitant medications
Physical examination (Section 10.2.5) and vital signs (Section 10.2.6) 
 
Skin examination (Section 10.2.5) 
Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry, hematology, and urinalysis (Section 10.2.1) 
Serum bile acids (Section 9.2.1) 
p-C4 and autotaxin 
AFP
Abdominal ultrasound (Section 10.2.7) 
Fibroscan, where available (Section 9.2.8) 
Administer PedsQL questionnaire
Urine pregnancy test for girls who have reached menarche
Patient/caregiver/clinician complete the PGIC and PGIS
AE monitoring
Evaluation of study drug compliance; dosage form acceptability questions will be asked of 
the caregiver and/or patient
Liver biopsy (if required; see Section 9.2.10) 
Patient/Caregiver decide whether to continue A4250 treatment 
 
Dispensing of drug for optional Extension Period (if applicable) 
7.1.3.4
Follow-up Visit
Week 76/Visit 12 (Patients/Caregivers not participating in Optional Extension Period)
Patients will return to the study site 28 days after Visit 11 or the last dose of study drug (for 
those patients who prematurely withdraw) for the following assessments: 
Document concomitant medications 
 
Vital signs (Section 10.2.6) 

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Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry and hematology (Section 10.2.1) 
INR
Serum bile acids (Section 9.2.1) 
Urine pregnancy test for girls who have reached menarche
 
AE monitoring 
7.1.3.5
Optional Extension Period
Week 88 and every 16 weeks thereafter up to commercial availability of drug
Document concomitant medications 
Vital signs (Section 10.2.6) 
Clinical Chemistry (Section 10.2.1) 
Serum bile acids (Section 9.2.1)
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1) 
INR
Urine pregnancy test for girls who have reached menarche
Administer PedsQL questionnaire
Patient/caregiver/clinician complete the PGIS and the PGIC
 
Evaluation of study drug compliance 
Study drug is dispensed 
 
AE monitoring 
7.1.3.6
Optional Extension Period End of Treatment
Upon commercial availability, patients should complete the End of Treatment (EOT) visit 
before starting commercial drug. For patients who decide to withdraw from the optional 
extension period prior to commercial availability, patients should immediately return to the site 
for the following EOT assessments:
Document concomitant medications 
Vital signs (Section 10.2.6) 
Clinical Chemistry (Section 10.2.1) 
Serum bile acids (Section 9.2.1)
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1)

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INR
Urine pregnancy test for girls who have reached menarche 
Administer PedsQL questionnaire 
Patient/caregiver/clinician complete the PGIS and the PGIC 
Evaluation of study drug compliance 
AE monitoring
7.2
Study Population
Cohort 1 will consist of approximately 60 children who completed 24 weeks, or who withdrew 
after a minimum of 12 weeks of treatment due to intolerable symptoms in Study A4250-005 
and meeting all inclusion criteria and no exclusion criteria are eligible for this study. Patients 
who withdraw from A4250-005 due to a study drug related AE will not be eligible. 
Cohort 2 will consist of approximately 60 patients with any type of PFIC who have elevated 
serum bile acids and cholestatic pruritus and who either (1) do not meet eligibility criteria for 
Study A4250-005 (PEDFIC 1) or (2) do meet the eligibility criteria for A4250-005 after 
recruitment of study A4250-005 has been completed. Up to 40 patients post biliary diversion 
surgery are allowed to participate in Cohort 2.
7.2.1
Inclusion Criteria
Cohort 1:
1. Completion of the 24-week Treatment Period of Study A4250-005 or withdrawn from
Study A4250-005 due to patient/caregiver judgment of intolerable symptoms after 
completing at least 12 weeks of treatment. Patients who withdraw from A4250-005 due to
a study drug related AE will not be eligible. 
2. Signed informed consent and assent as appropriate. Patients who turn 18 years of age (or 
legal age per country) during the study will be required to re-consent to remain on the study. 
3. Patients expected to have a consistent caregiver for the duration of the study.
4. Caregivers (and age-appropriate patients) must be willing and able to use an eDiary device 
as required by the study. 
Cohort 2:
1. A male or female patient of any age, with a clinical diagnosis of PFIC, including episodic 
forms (i.e., BRIC), and with a body weight 5 kg at Visit S-1.
2. Patient must have clinical genetic confirmation of PFIC.

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3. Patients with PFIC, excluding BRIC, must have elevated serum bile acid concentration,
s at least 7 days
apart (Visits S-1 and S-2) prior to the Screening/Inclusion Visit (Visit 1).
4. Patients with PFIC, excluding BRIC, must have history of significant pruritus and a 
caregiver-reported observed scratching or patient-reported itching (for patients >18 with no 
caregiver-reported observed scratching) 
2 weeks prior to the Screening/Inclusion Visit (Visit 1). 
5. Patients with episodic forms of PFIC (i.e., BRIC) must have an emerging flare
characterized by clinically significant pruritus and elevated serum bile acid
levels/cholestasis as judged by the investigator.
6. Patient and/or legal guardian must sign informed consent (and assent) as appropriate. 
Patients who turn 18 years of age (or legal age per country) during the study will be required 
to re-consent in order to remain in the study. 
7. Age appropriate patients are expected to have a consistent caregiver for the duration of the 
study.
8. Caregivers and age-
, if able) must be willing and able 
to use an eDiary device as required by the study. 
7.2.2
Exclusion Criteria
Patients meeting any of the following criteria at Visit 1 or Visit S-1 will not be eligible for 
study participation:
Cohort 1:
1. Decompensated liver disease: coagulopathy, history, or presence of clinically significant 
ascites, variceal hemorrhage, and/or encephalopathy. 
2. Sexually active males and females who are not using a reliable contraceptive method with
-uterine device, or complete 
abstinence) throughout the duration of the study and 90 days thereafter (from signed 
informed consent through 90 days after last dose of study drug). See Appendix 6 for further 
details.
3. Patients not compliant with treatment in study A4250-005.
4. Any other conditions or abnormalities which, in the opinion of the investigator or Medical 
Monitor, may compromise the safety of the patient, or interfere with the patient
participating in or completing the study. 
Cohort 2:
1. Known pathologic variations of the ABCB11 gene that have been demonstrated to result 
in complete absence of the BSEP protein.

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2. Patient with past medical history or ongoing presence of other types of liver disease 
including, but not limited to, the following: 
a) Biliary atresia of any kind.
b) Suspected or proven liver cancer or metastasis to the liver on imaging studies.
c) Histopathology on liver biopsy is suggestive of alternate non-PFIC related etiology of
cholestasis.
Note: Patients with clinically significant portal hypertension are allowed.
3. Patient with a past medical history or ongoing presence of any other disease or condition 
known to interfere with the absorption, distribution, metabolism (specifically bile acid 
metabolism), or excretion of drugs in the intestine, including but not limited to, 
inflammatory bowel disease.
4. Patient with past medical history or ongoing chronic (i.e., >3 months) diarrhea requiring 
intravenous fluid or nutritional intervention for treatment of the diarrhea and/or its 
sequelae.
5. Patient has a confirmed past diagnosis of infection with human immunodeficiency virus 
or other present and active, clinically significant, acute, or chronic infection, or past 
medical history of any major episode of infection requiring hospitalization or treatment 
with parenteral anti-infective treatment within 4 weeks of treatment start (Study Day 1) or 
completion of oral anti-infective treatment within 2 weeks prior to start of Screening
Period.
6. Any patient with suspected or confirmed cancers except for basal cell carcinoma, and 
non-liver cancers treated at least 5 years prior to Screening with no evidence of recurrence.
7. Patient has had a liver transplant, or a liver transplant is planned within 6 months of the 
Screening/Inclusion Visit. 
8. Decompensated liver disease, coagulopathy, history, or presence of clinically significant 
ascites, variceal hemorrhage, and/or encephalopathy. 
9. INR >1.4 (the patient may be treated with Vitamin K intravenously, and 
resampling the patient may be included).
10. Serum ALT >10 × upper limit of normal (ULN) at Screening.
11. Serum ALT >15 × ULN at any time point during the last 6 months unless an alternate 
etiology was confirmed for the elevation. 
12. Total bilirubin >10 × ULN at Screening.
13. Patient suffers from uncontrolled, recalcitrant pruritic condition other than PFIC. 
Examples include, but not limited to, refractory atopic dermatitis or other primary pruritic 
skin diseases.

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14. Any patient who is pregnant or lactating or who is planning to become pregnant within 
72 weeks of the Screening/Inclusion Visit. 
15. Sexually active males and females who are not using a reliable contraceptive method with
abstinence) throughout the duration of the study and 90 days thereafter (from signed 
informed consent through 90 days after last dose of study drug). See Appendix 6 for 
further details.
16. Patient with a past medical history of alcohol or substance abuse will be excluded. 
Patient must agree to refrain from illicit drug and alcohol use during the study. 
17. Administration of bile acid or lipid binding resins and medications that slow GI motility 
(Refer to Appendix 1 – Concomitant Medications Guidelines).
18. Patient has had investigational exposure to a drug, biologic agent, or medical device
within 30 days prior to Screening, or 5 half-lives of the study agent, whichever is longer. 
19. Any other conditions or abnormalities which, in the opinion of the investigator or Medical 
Monitor, may compromise the safety of the patient, or interfere with the patient
participating in or completing the study. 
20. Patient with surgical history of disruption of the enterohepatic circulation (biliary diversion 
surgery) within 6 months prior to start of Screening Period.
7.2.3
Withdrawal of Patients
Patients/caregivers will be informed that they have the right to withdraw from the study at any 
time, without prejudice to their medical care, and that they are not obliged to state their reasons.
Any withdrawal, and reasons for withdrawal, must be fully documented in the eCRF and source 
documents and the patient followed by the investigator/investigative staff. Withdrawn patients 
will not be replaced.
Patients will be withdrawn in the following circumstances:
A patient’s/caregiver’s desire for withdrawal for any reason
Lost to follow-up (every effort must be made to contact the patient/caregiver; a certified 
letter must be sent)
An AE which, in the opinion of the investigator, necessitates withdrawal 
Death
A patient’s/caregiver’s substantial non-compliance (eDiary and study drug compliance) or 
protocol violation

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An investigator’s opinion that continuing the patient in the study is not appropriate. The 
investigator may withdraw a patient at any time, if it is considered to be in the patient’s best 
interest 
Biliary diversion surgery or liver transplantation 
The reason and the date the patient is withdrawn from the study will be documented in the 
eCRF and source documents. If a patient is withdrawn from further treatment with the study 
drug, the investigator/investigative staff will attempt to complete all Visit 11 procedures at the 
time the patient is prematurely withdrawn from the study. The investigator/investigative staff 
will also attempt to complete all Visit 12 procedures 28 days following premature withdrawal 
(i.e., 28 days following the final dose of the study drug). 
If a patient discontinues prior to Week 72, additional telephone contacts will be made every 
3 months after the Follow-up Visit (Visit 12) up to Week 72 to gather whether or not the patient 
has had biliary diversion or liver transplantation, and of ongoing TEAEs at the time of 
discontinuation have resolved. The telephone calls will take place up until 72 weeks even if the 
patient has biliary diversion or liver transplant. 
7.2.4 
Study Termination by Sponsor 
This study may be terminated at any time by Albireo if significant safety concerns develop or, 
in the sponsor’s judgment, there are no further benefits to be achieved from continuation of the 
study. In this event, Albireo/designee will inform the study investigators, institutions and all 
regulatory authorities. 
Albireo may temporarily or permanently discontinue the study at an investigative site at any 
time for safety, ethical, compliance or other reasons. If this is necessary, Albireo will endeavor 
to provide advance notification to the site. If a site or the study is suspended or discontinued, 
the investigator/investigative staff will be responsible for promptly informing the Independent 
Ethics Committee (IEC)/Institutional Review Board (IRB) that this has happened. If required 
by local regulations, Albireo/designee will be responsible for informing the IEC/IRB and the 
Regulatory Authority of study or site discontinuation. In such an event, all study data and 
unused study drug must be returned to Albireo. 

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8
TREATMENT OF PATIENTS
8.1
Identity of Study Drug
A4250 will be supplied as capsules for oral administration. White opaque capsules filled with 
pellets containing A4250 will be provided. Two different capsule sizes will be available:
Capsule size 0 that can be opened
Capsule size 3 that should be swallowed intact. The size 3 capsules may be opened
only under exceptional circumstances, e.g., patient cannot swallow the capsule intact. 
Bottles with 34 capsules will be given to the patient at each visit. A patient who requires 2 or 
more capsules per day will be given multiple bottles. Refer to the Investigational Product 
Manual.
A 5-digit study drug number will identify study drug packs and will be detailed on the study 
drug label. Dispensing of study drug will be coordinated by the Interactive Web Response 
System (IWRS). The system will assign study drug number(s) using a packing list based on 
the patient’s weight and dose level (either 120 µg/kg/day or 40 µg/kg/day) for dispensation at 
each dispensing visit. In case of technical issues accessing the system online, please see the 
IWRS site user manual for country-specific contact telephone numbers to the ICON HelpDesk 
24/7 system support. 
8.2
Administration of Study Drug
Patients will be dosed with 120 µg/kg/day or 40 µg/kg/day4 for 72 weeks or 40 µg/kg/day for
the first 12 weeks followed by 120 µg/kg/day for the remaining 60 weeks4. Patients not 
tolerating the 120 µg/kg/day dose after a minimum of 1 week, for reasons other than new liver 
findings and severe diarrhea, will have the option to down-titrate to a lower dose 
(40 µg/kg/day). They should return to the higher dose as soon as deemed appropriate by the 
investigator.  More than one upward dose titration (from 40 µg/kg/day directly to
120 µg/kg/day) for the same event is not recommended. If, in the opinion of the investigator, 
a dose titration should be considered prior to the 1 week minimum, the investigator should 
consult with the Medical Monitor or designee.
Any dose titration should be done in 
consultation with the sponsor Medical Monitor or designee. 
Study drug will be dispensed to the patient at defined intervals from Visit 1 through Visit 9, 
together with instructions on how to store and take the drug. Study drug administration data, 
including whether each patient took each dose or partial doses of study drug, whether there
were any delayed or missed doses, and whether the capsule was opened or swallowed whole, 
will be documented through the diaries and transferred to the study database. 
4 As of Protocol Amendment 6.1 UK patients entering Cohort 2 will start treatment at 40 µg/kg/day with the 
possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus based on 
investigator judgment.

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Patients participating in the optional extension period will continue at the same dose as at the 
end of the 72-week treatment period (120 µg/kg/day or 40 µg/kg/day). Patients not tolerating 
the 120 µg/kg/day dose at any time throughout the extension period will have the option to 
down-titrate to a lower dose (40 µg/kg/day) following consultation with the sponsor Medical 
Monitor or designee. Patients should return to the higher dose as soon as deemed appropriate 
by the investigator. More than one upward dose titration (from 40 µg/kg/day directly to 
120 µg/kg/day) for the same event is not recommended. 
A4250 should be taken in the morning together with food. On clinic visits days when 
laboratory assessments are conducted (Visits 1 to 10; or Visits 1 to XX for those participating 
in the optional extension period), study drug should be taken after the visit. Patients should 
not crush or chew the capsule(s). When swallowing the capsule intact, the patient should 
administer the dose with a glass of water. 
If the study medicine needs to be mixed in a small amount of food because the patient is unable 
to swallow the capsule intact, the capsule can be twisted open and the contents sprinkled and 
mixed in a small amount (one or two tablespoons (15 to 30 mL)) of room-temperature yogurt, 
apple sauce, oatmeal, or fruit purée. If the patient has not yet been weaned onto solid foods, 
the capsule contents can be sprinkled into a small amount (a few milliliters) of water, baby 
formula or breast milk and administered with an oral dosing pipette. Please see Pharmacy 
manual for detailed instructions. 
If a patient’s weight changes at any time during the study, dose adjustment will be required. 
The number of capsules provided to the patient should be based on the body weight thresholds 
identified in Table 3. 
Table 3 
Dosing and Capsule Strength 
 
Body 
Weight (kg) 
Capsule 
Size 
Number of 
Capsules 
per Daya,b 
Capsule 
Strength, 
Low Dosea 
(µg) 
Total Dose 
(µg) a 
Capsule 
Strength, 
High Doseb 
(µg) 
Total Dose 
(µg) b 
5 to <7.5 
0 
1 
200 
200 
600 
600 
7.5 to <12.5 
0 
2 
200 
400 
600 
1200 
12.5 to <17.5 
0 
3 
200 
600 
600 
1800 
17.5 to <19.5 
0 
4 
200 
800 
600 
2400 
19.5 to <25.5 
3 
2 
400 
800 
1200 
2400 
25.5 to <35.5 
3 
3 
400 
1200 
1200 
3600 
35.5 to <45.5 
3 
4 
400 
1600 
1200 
4800 
45.5 to 55.5 
3 
5 
400 
2000 
1200 
6000 
>55.5 
3 
6 
400 
2400 
1200 
7200 
a Low dose: 40 µg/kg/day 
b High dose: 120 µg/kg/day 

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8.3 
Study Drug Packaging and Labelling 
8.3.1 
Packaging and Labelling 
The capsules will be packed in high-density polyethylene containers, with childproof 
polypropylene caps. Study drug capsules containing A4250 in the strength specified in the 
table above will be manufactured. 
Packaging and labelling will be prepared to comply with applicable regulatory requirements. 
8.3.2 
Storage 
Treatment packs containing A4250 capsules should be stored and dispensed in accordance with 
regulations in their original containers. The storage facility at the investigative site should be 
locked and storage should be between 15°C and 25°C. 
Patients/caregivers should be informed of appropriate storage conditions (i.e., room 
temperature, between 15°C and 25°C). 
Any deviations from the recommended storage conditions should be immediately reported to 
Albireo and the study drug should not be used until authorization has been given by Albireo. 
8.3.3 
Blinding and Randomization of Study Drug 
Not applicable. 
8.4 
Procedure for Breaking the Randomization Code 
Not applicable. 
8.5 
Patient Compliance 
The study nurse will monitor eDiary compliance by routine review of the CRF Health website. 
Patient/caregivers will be instructed to fill in the eDiary every morning and evening for the first 
24 weeks and the last 21 days before all the remaining visits to the clinic. There will be no 
interruption between Visits 11 and 12. Patients participating in the optional extension period 
will stop eDiary entries at Visit 11. If both diary entries on a day are missing during this time, 
the study nurse will call the caregiver/patient to remind them to complete all scheduled entries. 
Any non-compliance will be documented and explained in the source documents. 
Study drug compliance will be assessed by review of returned unused medication and by 
counting returned capsules at Visits 2 through 11 or Visits 2 through XX if participating in the 
optional extension phase, inclusive. Study drug compliance will be calculated for each patient 
and listed. 
Treatment Compliance = 100 × ((Number of study drug dispensed - number of study drug 
returned)/number of study drug that should be taken) 
Treatment compliance between 80% and 120% will be acceptable. 

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8.6 
Patient Identification 
After written informed consent is obtained from an eligible patient, an 8-digit patient 
identification number will be assigned. The first 2 digits will denote the country, followed by 
a 3-digit site number and a 3-digit patient sequence number. This number will be captured by 
the IWRS, when the patient first enters the system in A4250-008. Cohort 1 patients will be 
assigned the same patient number as used in the A4250-005 study, while Cohort 2 patients will 
be assigned a new unique patient number. 
8.7 
Study Drug Accountability 
Records shall be maintained of the delivery of study treatment to the study site(s), the inventory 
at the study site(s), the use of each patient and the return to Albireo. 
These records shall include dates, quantities, batch numbers, expiry dates and the unique code 
numbers assigned to the study drug and to the study patients. 
The investigator will be responsible for ensuring that the records adequately document that the 
patients were provided the quantities specified in the protocol and that all study drug received 
from Albireo is reconciled. 
8.8 
Concomitant Therapy and Prohibited Medications 
For Cohort 1 patients, the investigator will note all ongoing medication in the eCRF at Visit 1. 
For Cohort 2 patients, the investigator will note all ongoing medication and any medication 
recently stopped (within 1 month prior to Visit S-1) in the eCRF at Visit S-1. At Visits 2 to 
12, (and S-2 for Cohort 2) and visits in the optional extension period, all changes in medication 
(stopping or starting new medication or changes in dose) will be recorded in the eCRF. All 
medication (prescribed or over the counter) for pruritus, sleep, and vitamin supplementation 
will be recorded. 
All medications still being taken by a patient on or after first intake of study drug and which 
continue to be taken during the study are regarded as concomitant medication. 
The protocol allows for patients to be vaccinated against COVID-19 while in the study, based 
on the treating physician’s clinical assessment of the risks and benefits of study participation. 
Therefore, the COVID-19 vaccine can be administered as a concomitant medication. The date 
of COVID-19 vaccination must be recorded in the clinical database if administered during 
study participation. 
Concomitant medication guidelines are listed in Appendix 1. 

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9
ASSESSMENT OF EFFICACY
9.1
Efficacy Endpoints
9.1.1
Primary Efficacy Endpoints
The primary efficacy endpoints are:
EU and rest of world: Change from baseline in serum bile acids after 72 weeks of treatment.
US: Proportion of positive pruritus assessments at the patient level over the 72-week treatment 
period using the Albireo ObsRO instrument. 
9.1.2
Secondary Efficacy Endpoints
EU and rest of world: Proportion of positive pruritus assessments at the patient level over 
the 72-week treatment period using the Albireo ObsRO instrument. 
US: Change from baseline in serum bile acidsafter 72 weeks of treatment.
All Regions:
Change from baseline in serum bile acids at Weeks 4, 12, 22, 24, 36, 46, 48, 60, 70, 72, and
76
Proportion of individual assessments meeting the definition of a positive pruritus
assessment at the patient level using the Albireo ObsRO instrument from Weeks 0-4, 
Weeks 0-12, Weeks 0-22, Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, 
Weeks 0-60, and Weeks 0-70, respectively, or the proportion of positive pruritus 
assessments at each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then
by each visit between Visit 5/Week 24 to Visit 12/Week 76 
Proportion of individual AM assessments meeting the definition of a positive pruritus 
assessment at the patient level using the Albireo ObsRO instrument from Weeks 0-4, 
Weeks 0-12, Weeks 0-22, Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, 
Weeks 0-60, Weeks 0-70, and Weeks 0-72, respectively, or the proportion of positive 
pruritus  assessments
at  each
4-week
interval  between
Visit
1/Screening
and 
Visit 5/Week 24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 
Proportion of individual PM assessments meeting the definition of a positive pruritus 
assessment at the patient level using the Albireo ObsRO instrument from Weeks 0-4, 
Weeks 0-12, Weeks 0-22, Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, 
Weeks 0-60, Weeks 0-70, and Weeks 0-72, respectively, or the proportion of positive 
pruritus  assessments
at  each
4-week
interval  between
Visit
1/Screening
and 
Visit 5/Week 24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 
All-cause mortality, number of patients undergoing biliary diversion surgery or liver 
transplantation. These parameters will be evaluated separately and together at weeks 24,
48, and 72 

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Change in growth from baseline to Weeks 24, 48, and 72 after initiation of A4250
treatment, defined as the linear growth deficit (height/length for age, weight for age, mid- 
arm circumference, and body mass index [BMI]) compared to the standard growth curve
(Z-score, standard deviation [SD] from P50) 
Change in AST to platelet ratio index (APRI) score and Fib-4 score from baseline to Week 
72
Change in pediatric end-stage liver disease (PELD)/model for end-stage liver disease 
(MELD) score from baseline to Week 72
Change in use of antipruritic medication at Weeks 24, 48, and 72
9.1.3
Exploratory Efficacy Endpoints
All Exploratory Endpoints will be evaluated at Weeks 24, 48, and 72 unless otherwise noted. 
Baseline is calculated prior to initiation of A4250 treatment. Exploratory endpoints include:
Change in serum ALT, GGT, and total bilirubin concentration from baseline to Week 72
Proportion of individual assessments meeting the definition of a positive pruritus
assessment at the patient level over the 72-week Treatment Period. A positive pruritus 
assessment includes an itch score 
-point drop from baseline based on
the Albireo PRO instrument; 
the Albireo PRO 
instrument
Change from baseline over the 72-week treatment period in sleep parameters measured
with the Albireo PRO and ObsRO instruments
Change from baseline in INR, albumin, liver enzymes, leukocytes, and platelets
Change from baseline measures of bile acid synthesis (autotaxin, p-C4)
Assessment of Global Symptom Relief at Weeks 4, 12, 24, 48, and 72 as measured by 
patient, caregiver, and clinician PGIC items
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 
24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 in patient-reported and 
observer-reported night time itching and scratching severity scores, respectively
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 
24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 in patient-reported and 
observer-reported morning time itching and scratching severity scores, respectively
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 
24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 in pooled pruritus
score including observer-reported scratching for patients <8 years of age and patient- 
reported itch severity for pa
years of age
a

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Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 
24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 in additional patient- 
reported and observer-reported sleep parameters (e.g., tiredness, number of awakenings) 
Change from baseline in PedsQL questionnaire
Change from baseline in stage of liver fibrosis as assessed by Fibroscan® (where available)
Change from baseline in stage of liver fibrosis as assessed by post-treatment biopsy (when 
available)
9.2
Efficacy Assessments
9.2.1
Serum Bile Acids
Blood samples for analysis of fasting serum bile acids will be drawn at all study visits from
Visit 1 (Visit S-1 for Cohort 2) through Visit 12. Fasting serum bile acids will also be drawn 
at all visits during the optional extension period. Patients will fast (only water intake is 
permissible) for at least 4 hours prior to the collection of samples for serum bile acids. 
Exceptions can be made for infants, less than 12 months of age, if unable to fast for the full 4 
hours. For any visit at which a bile acid sample result is unreportable, an additional 
unscheduled visit for a repeat sample collection may be scheduled. Samples will be handled 
and transported to a central laboratory per instructions in the laboratory manual. 
9.2.2
Itching and Sleep Score
Itching, observed scratching, and sleep disturbance will be assessed twice each day via eDiary. 
Patient/caregivers will be instructed to fill in the eDiary every morning and evening for the first 
24 weeks and the last 21 days before all the remaining visits to the clinic. There will be no 
interruption between Visits 11 and 12. Patients participating in the optional extension period 
will stop eDiary entries at Visit 11. Patients and/or caregivers will be instructed to complete
the eDiary in the morning after the patient wakes and in the evening just before the patient goes 
to sleep. 
The eDiary includes Albireo ObsRO and PRO items. Patients <8 years of age will not be asked 
to complete the Albireo PRO items; only the Albireo ObsRO will be completed by caregivers
items and the caregiver will complete the Albireo ObsRO items. The Albireo PRO items assess 
severity of itch, aspects of sleep disturbance (morning diary only), and tiredness. For patients 
8 to 12 years of age, the caregiver will read the Albireo PRO items along with the child and 
record the child’s response. A guide will be provided to the caregivers that provides 
standardized explanations of the Albireo PRO items, in case the patient is confused or requires 
clarification about the meaning of a question. The Albireo ObsRO items assess severity of 
observed scratching, aspects of observed sleep disturbance (morning diary only), and observed 
signs of tiredness (evening diary only).  The Albireo ObsRO and PRO scratching and itch

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severity items use 0 to 4 response scales, where each response is distinguished by a unique 
facial expression, verbal anchor, number, and color code (Appendix 2).
A daily score AM and PM for the Albireo ObsRO scratching item will be averaged from the 
2 ratings for each day. A daily score will be considered missing if both of the daily 
assessments are missing. A weekly score will be calculated by averaging the daily scratching 
scores. A weekly score will be considered missing if 4 out of 7 days a week of data are 
missing. For AM and PM baseline, a 14-day daily score of AM and PM prior to the first dose 
of study medication will be averaged as the baseline score. 
For AM baseline, a 14-day AM score prior to the first dose of study medication will be 
averaged as the baseline AM score. The same approach will be used for PM baseline and to 
calculate a patient-reported itch severity score.
9.2.3
Growth
Growth (height and weight) will be measured by the standardized assessments outlined in the 
US FDA guidance document, Orally Inhaled and Intranasal Corticosteroids: Evaluation of the 
Effects on Growth in Children (March 2007). Height and length (velocity) will be measured 
using a certified stadiometer and weight (Z-score) using a certified weight scale.
Mid-arm circumference (3 repeat measurements) will be collected at the study site.
Study sites will be trained on using a standardized approach when measuring height with a 
stadiometer and additional detailed instructions will be provided in study documents. 
BMI will be calculated by weight (kg) / height (m)2. Change will be defined as linear growth 
deficit (weight and BMI for age) compared to a standard growth curve. 
9.2.4
Biomarker Samples
Blood samples for p-C4 and autotaxin will be drawn at Visits 1, 2, 5, 8, and 11 (p-C4 and 
autotaxin will only be drawn for patients with body weight >10 kg). Samples will be treated 
and transported to a central laboratory per instructions in the laboratory manual. 
9.2.5
Change of Antipruritic Medication
Any change of antipruritic medication must be noted in the eCRF.
9.2.6
Quality of Life Questionnaire (PedsQL)
Caregivers and, if applicable, patients will be asked to fill out a QoL questionnaire (PedsQL) 
at Visits 1, 5, 8, 11 and at all visits of the optional extension period. Details of the questions 
included on the questionnaire can be found in Appendix 4. 
9.2.7
PELD/MELD Score
The PELD score will be calculated for children up to 12 years of age. For patients 13 years or 
older, the MELD score will be calculated.

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PELD Score = 4.80 * ln(total bilirubin) + 18.57 * ln(INR) - 6.87 * ln(albumin) + 4.36 (if patient
<1 year: scores for patients listed for liver transplantation before the patient’s first birthday 
continue to include the value assigned for age (<1 year) until the patient reaches the age of 24 
months) + 6.67 (if patient has growth failure [<-2 SD])
Laboratory values less than 1.0 will be set to 1.0 for the calculation of the PELD score. 
MELD Score = 9.57 * ln(creatinine) + 3.78 * ln(total bilirubin) + 11.2 * ln(INR) + 6.43 
Laboratory values less than 1.0 will be set to 1.0 and serum creatinine values greater than
4.0 mg/dL (equivalent to 353.6 µmol/L) will be set to 4.0 for calculation of the MELD score.
If a patient goes from 11 years of age to 12 between the beginning and end of study, both PELD 
and MELD scores will be calculated at the first visit after the 12th birthday and move to MELD 
score. The results should be displayed in one summary table. 
9.2.8
Fibroscan®
Where available, Fibroscan® will be performed as per institution standard practice at Visits 1, 
5, 8, and 11. 
9.2.9
Markers of Fibrosis
APRI score and Fib-4 score will be calculated at Visits 1, 3, 5, 8, and 11.
APRI = [(AST in U/L) / (AST upper limit of normal [ULN] in U/L)] x 100 / (Platelets in 109/L) 
Fibrosis 4 Score = (Age*AST in U/L) / (Platelets in 109/L *  (ALT in U/L))
9.2.10
Liver Biopsy
If a liver biopsy is performed according to the local regulations or standard of care at any time 
during A4250-008, the biopsy results should be recorded in the eCRF. If the patient has liver 
biopsy results collected in study A4250-005 or prior to Week 24 in study A4250-008, the
patient will be asked to consent to a follow up liver biopsy, if allowed per local regulations, at 
Visit 11 unless 2 prior liver biopsy results have been collected with at least 1 year between 
biopsies. Liver biopsies will not be performed in Spain. 
9.2.11
Global Impression of Change and Global Impression of Symptom Measures
Patients, caregivers, and clinicians will complete the PGIC and the PGIS measures at Visits 1,
2, 3, 5, 8, 11, and at all visits of the optional extension period (Appendix 3).
The PGIC items assess change in itch (patient version), scratching (caregiver and clinician 
versions), and sleep (all versions) since starting the study drug. The PGIS items assess itch 
(patient version), scratching (caregiver and clinician versions), and sleep (all versions) in the 
past week. Caregivers and clinicians will complete the PGIC and PGIS for all patients; those 
years of age will complete the patient version.

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10
ASSESSMENT OF SAFETY
The timing and frequency of safety assessments are described in Section 7.1.2 and 
Section 7.1.3. 
The primary safety analysis for this study will include the incidence of total treatment-emergent 
adverse events (TEAE) and TEAEs categorized by causality, severity, and seriousness 
assessments.
Trends in safety will also be evaluated for the following assessments:
Physical examinations
Concomitant medications 
Vital signs
Laboratory test results (including clinical chemistry, hematology, urinalysis, AFP, vitamins 
A, E, and 25-hydroxy vitamin D, and INR) 
Abdominal ultrasound
Discontinuations due to AEs
10.1
Adverse Events
10.1.1
Definitions and Investigator Assessments
An AE is defined as any untoward medical occurrence in an enrolled patient regardless of
causal relationship with study drug. An AE can therefore be any clinically significant 
unfavorable and unintended sign, symptom, or disease that occurs once a patient is enrolled
(ICF is signed) in the study until the patient is discharged from the study, whether or not related 
to the study drug. 
10.1.1.1
Clinical Significance
Clinical significance is defined as any abnormal finding that results in further clinical 
investigation(s), treatment(s), or the diagnosis of new condition. Patient-reported events and 
protocol-mandated laboratory values, vital signs, and physical examination findings can be 
considered clinically significant (i.e., an AE) if there is a deterioration as compared to baseline. 
Examples of clinically significant worsening from baseline could include, but is not limited to, 
events causing withdrawal from the study and events requiring medical intervention outside of 
the study causing apparent clinical manifestations, or judged relevant by the investigator.
10.1.1.2
Serious Adverse Events
Serious criteria are applied by the investigator to each AE as specifically defined below. These 
criteria are used to determine whether an AE is serious or non-serious. The assessment is made 
independently of severity assessment (Section 10.1.1.3). For example, the development of a 

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severe rash that occurs after signing of informed consent may not meet serious criteria as 
defined below and therefore would be considered a severe, non-serious AE.
Any AE that meets any 1 of the following 6 criteria is considered an SAE: 
The outcome of the AE is death
The AE is immediately life-threatening. Life-threatening means that the patient is, in the 
opinion of the investigator, at immediate risk of death from the reaction as it occurred. This 
does not include an AE that, if more severe, might have caused death
The AE results in persistent or significant disability/incapacity. Disability means a 
substantial disruption of a person's ability to conduct normal life functions
The AE requires or prolongs hospitalization
The AE results in a congenital anomaly/birth defect
The AE is an important medical event. Important medical events may meet serious 
criteria should the investigator assess that they may significantly jeopardize the patient, 
represent a significant hazard, or requires medical/surgical intervention to prevent one of
the outcomes listed above. Examples of potential SAEs based on this criterium include, 
but are not limited to, allergic bronchospasm requiring intensive treatment in an emergency 
room or at home, blood dyscrasias or convulsions even if they do not result in inpatient 
hospitalization, or the development of drug dependency and drug abuse. 
10.1.1.3
Severity Assessment
Severity assessments are based on the intensity of the event in relation to expectation. The 
investigator will assess the intensity of AEs based on the following definitions: 
Mild (awareness of sign or symptom, but easily tolerated)
Moderate (discomfort sufficient to cause interference with normal activities)
 
Severe (incapacitating, with inability to perform normal activities) 
Severity is a measure of intensity where seriousness is defined by the criteria outlined in
Section 10.1.1.2. An AE of severe intensity need not necessarily be considered serious. For 
example, nausea that persists for several hours may be considered severe nausea, but not meet 
serious criteria, and therefore would be assessed as a severe AE but not an SAE.
10.1.1.4
Causality Assessment
The investigator determines the causality of all AEs to the study drug using medical judgment 
and considering all relevant factors such as (but not limited to) the underlying study indication, 
coexisting disease, concomitant medication, relevant history, pattern of the AE, temporal 
relationship to the study drug, and de-challenge or re-challenge. The causality assessment of
the AE/SAE is to be made as follows.

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Related to study drug (possibly, probably, or definitely related)
Based on medical judgment, there is at least a reasonable possibility that the study drug caused 
the event; one or more of the following criteria apply:
The event follows a reasonable temporal sequence from administration of study drug
The event could not be reasonably attributed to the known characteristics of the patient's 
clinical state, environmental or toxic factors, or other modes of therapy administered to the 
patient
The event follows a known pattern of response to study drug
The event disappears or decreases on cessation or reduction in dose of the study drug. (It 
should be noted that in some situations an AE will not disappear or decrease in intensity 
upon discontinuation of study drug despite other clear indications of relatedness) 
The event reappears or worsens when the study drug is re-administered
Unrelated to study drug (unlikely or unrelated)
Based on medical judgment there is no reasonable possibility that the study drug caused the 
event; one or more of the following criteria apply: 
The event does not follow a reasonable temporal sequence from administration of study
drug
The event could be reasonably attributed to the known characteristics of the patient's
clinical state, concurrent illness, environment or toxic factors, or other modes of therapy 
administered to the patient
The event does not follow a known pattern of response to study drug
The event does not disappear or decrease on cessation or reduction in dose of the study
drug, and it does not reappear or worsen when the study drug is re-administered
10.1.2
Recording of Adverse Events
It is the investigator’s responsibility to assess whether each untoward event is a clinically 
significant worsening from baseline, thereby considered an AE. For all AEs, the severity, 
seriousness, and causality to study drug for each AE as outlined in Section 10.1.1 will be 
assessed and recorded in the eCRF.
All serious and non-serious AEs are collected once the caregiver/patient has signed the ICF 
and until the post-treatment follow-up (Visit 12), 28 days after the last dose of study drug. 
Collection of all serious and non-serious AEs will continue for the optional extension period. 
Any AEs or SAEs that are unresolved at the patient’s last AE assessment in the study are 
followed up by the investigator until resolution or stabilization up to the database lock and

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recorded in the eCRF. Albireo retains the right to request additional information for any patient 
with ongoing AE(s) or SAE(s) at the end of the study. 
TEAEs that are ongoing at time of discontinuation will be followed up until week 72 by 
telephone calls every 3 months. No new AEs will be recorded after the patient has permanently 
discontinued study drug. 
TEAEs are defined as any AE that occurs after dosing (Day 1), including new AEs or the 
worsening of an event after the first dose.
If there is a clinically significant deterioration of a laboratory value/vital sign or other routine 
study assessment that is associated with a diagnosis, the clinical diagnosis will be reported as
an AE and the associated signs and symptoms will be considered additional information unless 
the sign or symptom is more severe than expected given the diagnosis. For example, if an 
investigator diagnoses a study patient with hepatitis during the study period, hepatitis would 
be considered the AE and the concomitant signs and symptoms of abdominal pain, vomiting, 
and elevated ALT and AST would not be reported separately unless, in the opinion of the 
investigator, one of these signs or symptoms is more severe than expected and therefore a 
separate AE assessment is indicated.
10.1.3
Recording and Reporting of Serious Adverse Events
Every SAE (regardless of severity and causality) that occurs once the caregiver/patient has 
signed the ICF and until the post-treatment follow-up (Visit 12), and 28 days after the final 
dose of study drug, should immediately and not later than within 24 hours of knowledge of the 
event, be reported by the investigator or delegate in the SAE Report Form. 
Report of a SAE must include at least the following information:
Patient identification information (study number, site number, initials, and date of birth [as 
per local country requirements for data protection]) 
The last study drug administration date
The  diagnosis  of  the  event  with  the  description  (or  a  brief  description  of 
signs/symptoms/clinical course if the diagnosis is not available) and the date of onset
The action used to treat the event (i.e., treatment medications, temporary discontinuation) 
The reason(s) for considering the event serious
The relationship of the event to the study drug or to the study procedure (e.g., the 
investigator's assessment of causality)
A brief narrative of the SAE
Follow-up reports including all new information obtained of the subsequent course of the SAE 
must be prepared and the information collected in the SAE Report Form submitted to ICON

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DRUG SAFETY (Pharmacovigilance and Safety Services Department) by e-mail within 
24 hours of knowledge of the event. 
The pharmacovigilance manager (PVM) may contact the investigator to obtain further 
information on a reported SAE. The investigator/investigative staff must respond to any 
request for follow-up information or answers to questions regarding the SAE within the same 
timelines as for initial reports. 
The PVM reports the occurrence of the SAE and follow-up to the Albireo Medical Monitor for 
medical assessment of the case. 
Should an outcome of death occur within the study period or within 28 days after the last 
administration of study drug, an SAE Report Form should be completed including the main 
and contributory causes of death. 
All SAE reports must be e-mailed to the following e-mail address within 24 hours: 
ICON DRUG SAFETY (Pharmacovigilance and Safety Services Department) 
E-mail: 
 
If email is unavailable, SAEs may be transmitted via fax to the following number: 
Fax No.: 
 
In a study-related medical emergency situation, when the assigned Medical Monitors for the 
study cannot be reached by a caller, an on-call physician can be reached 24 hours per day, 
7 days per week, via the ICON call center. The following number is a chargeable telephone 
number allowing a global reach from both landlines and mobile phones and the internet page 
indicated below contains a list of country-specific toll-free telephone numbers. It should be 
noted that not all countries globally have access to toll-free numbers as indicated on the 
“24/7 Medical Help desk” index. Countries without toll-free numbers need to dial the 
chargeable number as indicated below. Furthermore, toll-free numbers might not be available 
from mobile phones. 
On Call Telephone No.: 
 
https://icophone.iconplc.com 
10.1.4 
Reporting of Suspected Unexpected Serious Adverse Reactions 
Suspected unexpected serious adverse reaction (SUSAR) is an SAE that occurs in a patient, 
the nature or severity of which is not expected per the applicable product information (e.g., the 
IB for an unauthorized investigational product or summary of product characteristics for an 
authorized product). 
Reporting and tracking of SUSARs will be in accordance with all applicable competent 
authority regulations. The Ethics Committees and all investigators involved in this study will 
be informed according to national and international requirements. 
PPD
PPD
PPD

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10.2 
Laboratory Values/Vital Signs/Physical Examinations and Other Safety 
Assessments 
10.2.1 
Laboratory Assessments 
At the clinic visits indicated in Table 1, samples will be drawn for clinical chemistry, 
hematology, and urinalysis analyses. The parameters assessed are presented in Table 4. 
Blood for AFP will be drawn at Visits 1, 5, 8, and 11. Fat-soluble vitamin levels including 
vitamins A and E, and 25-hydroxy vitamin D will be assessed at Visits 1, 3, 4, 6, 7, 9, 10, and 
all optional extension period visits and INR (surrogate for vitamin K) will be assessed at Visits 
S-2 (Cohort 2 only), 2, 3, 4, 6, 7, 9, 10, and 12, and all optional extension period visits. Patients 
will fast (water intake only is permissible) for at least 4 hours prior to the collection of samples 
for vitamin A. Exceptions can be made for infants, <12 months of age, if unable to fast for the 
full 4 hours. If a patient has any vitamin level(s) that are outside of the reference range, vitamin 
supplementation adjustments may be required. Target ranges and supplementation strategy 
guidelines can be found in Appendix 5. 
A serum pregnancy test will be performed at Visits S-1 (Cohort 2) and Visit 1 (Cohort 1), and 
a urine pregnancy test will be collected at all other visits, including the optional extension 
period visits, for girls who have reached menarche. If a urine pregnancy test is positive, a 
serum pregnancy test should be performed to confirm the pregnancy. Study drug 
administration will be held pending the confirmatory results. If the serum pregnancy test is 
negative, the patient can resume dosing. If the serum pregnancy test is positive, the patient 
should be discontinued (see Section 10.2.9). 
All samples will be processed and transported to a laboratory per instructions in the laboratory 
manual. 
The observed values will be recorded and assessed as “normal” or “abnormal not clinically 
significant” or “abnormal clinically significant”. 
For hepatic adverse events and/or hepatic decompensation, a PK sample should be collected as 
close to the onset of the event as possible (PK samples are not required during the screening 
period). 
Additional safety blood samples may be needed due to follow-up of an abnormal value or 
analysis failure. The blood samples collected for safety laboratory analysis will be destroyed 
after the analyses have been completed. 

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Table 4 
Routine Laboratory Parameters
Clinical Chemistry
Hematology
Urinalysis
Albumin*
Hematocrit
Blood
ALT*
Hemoglobin
Glucose
Alkaline phosphatase*
Platelet count
Ketones
AST*
Red blood cell count
Leukocytes
Bilirubin – total and 
conjugated*
Calcium 
Chloride
White blood cell count and 
differential (neutrophils, 
eosinophils, basophils, 
lymphocytes, and monocytes)
Nitrites 
pH 
Protein
Creatinine
Creatine kinase
GGT
Potassium
Sodium
* Clinical chemistry for 
optional extension period
10.2.2
Individual Patient Safety Monitoring
10.2.2.1
Liver Monitoring
Strategies to monitor markers of liver disease throughout the study are outlined below where
the ULN will be based on central laboratory reference values for age and gender.
For abnormalities classified as hepatic adverse events and/or hepatic decompensation, a PK 
sample should be collected as close to the onset of the event as possible (PK samples are not 
required during the screening period).
If isolated transaminase elevations are observed, defined as:
1. Normal bilirubin AND absence of clinical hepatitis symptoms AND
whichever comes first
U/L, whichever comes first
Then:
a) Repeat liver profile (AST, ALT, bilirubin, and prothrombin time [PT] or INR) within 
2 to 3 days 
b) Evaluate creatine phosphokinase (CPK) and lactate dehydrogenase (LDH)
c) As needed (for example, persistent ALT/total bilirubin elevation or worsening of liver 
function), consider evaluation for alternative etiologies 

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Monitor the patient using close observation found in Section 10.2.2.2.
If any ONE of the following criteria are met:
1.
 
 or absolute threshold increase of +300 U/L,
whichever comes first) AND bilirubin increases to such where total bilirubin > 2 × ULN if 
total bilirubin was within normal range at baseline
2. Transaminase elevations alone (ALT or AST >5 × ULN for patients that were normal at 
baseline) or absolute threshold of +300 U/L (for patients starting with transaminases above 
ULN at baseline) in presence of normal LDH and CPK
3. Total bilirubin increased, unrelated to hemolysis (elevated reticulocyte count) or
established genetic diseases, such as Gilbert’s syndrome
a)
Doubling if total bilirubin was <3 mg/dL (equivalent to 51.3 µmol/L) at baseline and 
total bilirubin is greater than 2 × ULN 
b)
OR Increase by >3 mg/dL (equivalent to 
(equivalent to 51.3 µmol/L) at baseline
4. INR increase refractory to vitamin K administration
a)
Increase by >1.5 if INR was normal at baseline
b)
OR Increase by >0.4 if INR was abnormal at baseline
5. Any increase in total bilirubin and transaminases if accompanied by EITHER a symptom 
of clinical hepatitis (e.g., vomiting, nausea, right upper quadrant pain) OR immunological 
reaction (rash or >5% eosinophilia) 
Then:
a)
Interrupt study medication
b)
Initiate drug-induced liver injury work-up for alternative etiologies
c)
Repeat liver profile (AST, ALT, total bilirubin, direct bilirubin) and PT or INR within 
48 to 72 hours 
d)
Monitor the patient using close observation found in Section 10.2.2.2
e)
If a patient lives in a remote area, they may be tested locally and the results 
communicated to the investigator site promptly
10.2.2.2
Close Observation
Repeat liver enzyme and serum bilirubin tests two or three times weekly. Frequency 
of re-testing can decrease to once a week or less if abnormalities stabilize or the trial 
drug has been discontinued and the patient is asymptomatic 
Obtain a more detailed history of symptoms and prior or concurrent diseases

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Obtain a history of concomitant drug use (including non-prescription medications and 
herbal and dietary supplement preparations), alcohol use, recreational drug use, and 
special diets
Consider ruling out alternate etiology including acute viral hepatitis types A, B, C, D, 
and 
E; 
autoimmune 
or 
alcoholic 
hepatitis; 
non-alcoholic 
steatohepatitis; 
hypoxic/ischemic hepatopathy; and biliary tract disease 
Obtain a history of exposure to environmental chemical agents
Obtain additional tests to evaluate liver function, as appropriate (e.g., INR, direct 
bilirubin)
Consider gastroenterology or hepatology consultations
Follow subjects with potential drug-induced liver injury (DILI) until the laboratory, and 
new associated clinical abnormalities have normalized or returned to baseline 
(enrollment) values or have stabilized (defined as laboratory values being stable for 
3 months). Continue to work up for alternate etiologies for the abnormal liver disease 
as stated above until case has resolved. If imaging changes are found as part of the 
assessment for etiology, these should be continued to be followed until normalization 
or returned to baseline or until the investigator feels the changes have stabilized.
10.2.2.3
De-challenge/Re-challenge for Liver and Clinical Hepatitis Monitoring
1. Re-challenge is not recommended:
a) If a patient has had possible/probable drug-induced liver injury
b) If a decompensation event has occurred (i.e., variceal hemorrhage, ascites, hepatic 
encephalopathy, etc.). 
2. If the event is assessed as due to underlying cholestatic liver disease variability or another 
alternative etiology is identified AND liver tests returned to baseline, re-challenge may be 
considered after consultation with the sponsor Medical Monitor.
3. If the ALT/total bilirubin elevations are observed after re-challenge, then repeat
re-challenge is discouraged.
If a patient is permanently discontinued, monitoring should be continued as outlined in 
Section 10.2.2.8.
10.2.2.4
Diarrhea
Study drug should be discontinued if a patient develops diarrhea with at least 1 of the following 
concomitant signs or symptoms: grossly bloody stools, vomiting, dehydration requiring
°C)
and/or the diarrhea persists for 7 or more days.
should be assessed using hemoccult cards. 

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Blood in stools or any other signs of bleeding should trigger clinical and laboratory assessment 
such as measurement of PT/aPTT, INR, platelets, etc. Any deficits should be corrected, as 
clinically indicated.
Cause of bleeding should be investigated, and an evaluation should be obtained. If there is a 
reduction in hemoglobin greater than 2 g/dL there should be a discussion with the Medical 
Monitor and the appropriate work up will be decided. Information needed for this discussion 
should include presence of any diarrhea, recent iron studies, any signs of gross bleeding and 
what organs are involved, recent and current complete blood count, INR, any changes in heart 
rate, blood pressure, weight, last results of imaging and endoscopy/ colonoscopy and recent 
infectious work up, if done. 
If gross blood in stool/bleeding is seen, an AE of blood in stool/bleeding should be reported.
Study drug will be reintroduced (re-challenge) when the symptoms have resolved. If the 
diarrhea re-occurs within 1 week after the re-challenge with no alternate etiology, the patient 
will be permanently discontinued and monitored as outlined in Section 10.2.2.8.
10.2.2.5
Fat-soluble Vitamin Deficiency
Queries related to TEAEs indicative of end-organ damage, i.e., impaired hepatic synthetic 
function presenting as e.g., bone fracture/rickets, GI or other organ bleeding/ecchymosis or
night blindness, will be issued when a patient presents with worsening of fat-soluble vitamin 
deficiency (see Section 10.2.1 for monitoring fat-soluble vitamin levels by laboratory 
assessments). Treatment should be discontinued in patients with evidence of end-organ damage 
due to fat-soluble vitamin deficiency.
10.2.2.6
Treatment-emergent Iron Deficiency Anemia
Events of iron deficiency anemia are identified as part of TEAE reporting and hematology 
assessments. Patients will be evaluated for fecal blood loss if they present with:
A decrease
 2 g/dL
A report of blood in stool; if so, a further diagnostic work up will be performed, 
following confirmation of blood in stool with hemoccult cards. 
Patients will be managed per institutional standard of care with iron supplementation.
10.2.2.7
Re-challenge after Discontinuation/Interruption of Study Drug
The DSMB will evaluate the safety data for patients who have discontinued study drug for an 
extended period on a case-by-case basis to determine whether re-challenge with A4250 is 
appropriate. The minimal duration of the discontinuation should be at least one to two weeks.
Patients that have discontinued for an extended period and allowed re-challenge by DSMB will 
use the last labs prior to restart as the new baseline for determining if DILI criteria are met.

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10.2.2.8 
Monitoring after Permanent Discontinuation of Study Drug Due to Safety 
Once study drug is permanently discontinued for liver, hepatitis, diarrhea, or other severe AE 
related to study drug, the patient will be monitored weekly until the laboratory and clinical 
parameters have normalized/stabilized. 
10.2.3 
Demographics/Medical and Surgical History (For Cohort 2 only) 
Demographic information per country regulations, along with medical and surgical history, 
will be obtained and recorded in the eCRF at Visit S-1. 
Medical and surgical history will be entered in the eCRF at Visit S-1. This includes date of 
diagnosis of PFIC, prior investigational medications for PFIC, historical (3 months prior to 
Screening, and up to 5 years prior to Screening for BRIC) hepatic biochemical parameters (e.g., 
AST, ALT, and total bilirubin), ongoing medication, any surgery performed, any other 
diagnosis, and historical biopsy data. 
For patients with BRIC, information on flares will be collected, including frequency, duration, 
and severity of flares within the last 6 months at a minimum, and within the last 5 years, if 
possible. A flare/cholestatic episode can be self-reported or clinically assessed based on 
medical history. Clinical signs and symptoms during a cholestatic episode/flare can include 
nausea, vomiting and pruritus followed by jaundice, fatigue, weight loss, malaise, steatorrhoa, 
night blindness. Increased bilirubin and alkaline phosphatase levels and increased INR can be 
observed. ALT, AST and GGT can be normal to mildly elevated. 
If a liver biopsy has been performed within 1 year prior to Screening, or during the study, the 
results will be recorded in the eCRF. 
10.2.4 
Clinical Genetic Testing (For Cohort 2 only) 
For previous confirmatory clinical genetic testing results for PFIC, including BRIC, Type 
performed prior to Screening Visit S-1, the confirmatory clinical genetic testing laboratory 
report will be verified to determine eligibility. 
If the historical clinical genetic result is equivocal, unavailable, or unobtainable, clinical 
genetic analysis will be performed to confirm pathologic biallelic variations of the ATP8B1, 
ABCB11 ABCB4, NR1H4, TJP2, DCDC2, CLDN1, and MYO5B genes and verified to 
determine eligibility. No other diagnostic genetic testing will be offered. 
10.2.5 
Physical Examination 
A physician or suitably trained qualified assistant will perform a complete physical 
examination, including a skin examination, at Visits S-1, 1, 3, 5, 8, and 11. 
A complete physical examination will include assessment of general appearance, eyes, ears, 
nose, throat, head/neck/thyroid, lymph nodes, cardiovascular, lungs/chest, abdomen, 
genitourinary, extremities, skin, musculoskeletal, neurologic, and other.  An abbreviated 

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physical examination will include general appearance, cardiovascular, abdomen, and other 
assessments based on patient status. 
Skin will be thoroughly examined and excoriations/scratch marks recorded. 
10.2.6 
Vital Signs 
Evaluation of vital signs will be performed at all visits. This includes blood pressure (systolic 
and diastolic), pulse, respiratory rate, temperature, height/length (using certified stadiometer), 
mid-arm circumference (3 repeat measures), and body weight (using a certified weight scale) 
at clinic visits. BMI will be calculated. 
10.2.7 
Abdominal ultrasound 
Ultrasound of the liver and spleen will be performed at Visits 1, 5, 8, and 11. Liver size, 
echogenicity, and presence of masses/nodules as well as spleen size will be recorded. If an 
ultrasound is performed as standard of care during the optional extension period, the data 
should be recorded in the electronic case report form (eCRF). 
10.2.8 
Overdose 
A4250 is minimally absorbed and has a very low systemic availability. Based on toxicology 
data, for study purposes any dose exceeding a total of >3 mg/kg body weight of A4250 taken 
as a single dose or as a cumulative dose within 24 hours is defined as an overdose. 
The no-adverse-effect dose level in the most sensitive species (defined as 20 mg/kg/day) in the 
rat 1 month toxicity study gives a human equivalent dose of approximately 194 mg/day in a 
60 kg person. This dose is approximately 10-fold higher than the maximum possible dose 
predicted in human studies (20 mg). 
The investigator/investigative staff should immediately, and not later than within 24 hours of 
knowledge, report an overdose in the SAE Report Form. In the event of an A4250 overdose, 
the patient should be monitored closely. 
10.2.9 
Pregnancy 
If a pregnancy is discovered in a female patient enrolled in the study before the end of dosing 
the patient will be immediately discontinued from the study and will attend the same visits as 
a prematurely withdrawn patient. If the pregnancy is discovered after the end of dosing the 
patient will continue in the study per protocol. If a pregnancy occurs in a male patient’s partner 
at any time during the study, the pregnancy should also be reported and followed. 
Pregnancy is not considered to be an AE. However, if the patient has been dosed with the study 
drug, the pregnancy must be reported on the Paper Pregnancy Notification Form immediately 
within 24 hours after recognition to Pharmacovigilance Manager and Pharmacovigilance and 
Safety Services Department (please refer to Section 10.1.3). Date of exposure and as far as 
possible, details of the period of gestation at the time of exposure must be given. 

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The pregnancy should be followed up to determine outcome, including spontaneous 
termination, details of birth, and presence of any birth defects, congenital anomalies or 
newborn or maternal complication. An infant who was exposed in-utero will be followed for 
up to 2 years after delivery. Individual cases with an abnormal outcome in association with 
the study drug should be reported on an expedited basis, i.e., reported rapidly to a competent 
authority. 

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11 
STATISTICAL EVALUATION 
11.1 
Sample Size and Power 
There is no formal hypothesis testing in this open label study. Sample size for Cohort 1 was 
determined in Study A4250-005. For Cohort 1, patients will be enrolled following completion 
or participation of 12 weeks of Study A4250-005. The expected proportion of patients with at 
least one event, i.e., surgical bile diversion or liver transplantation or death, in untreated 
patients is expected to be high enough to be able to detect an improvement after A4250 
treatment. For the other endpoints, mainly descriptive analyses will be performed. 
The proportion of patients with at least one event (i.e., surgical bile diversion or liver 
transplantation or death), that can be expected in a non-treated population depends on PFIC 
type and age distribution of the included patients. The expected proportion of patients with 
events will be calculated for the study population once each patient’s age and PFIC type are 
known, using the probability that a patient will get an event estimated from the reference 
population in the ongoing observational cohort study, NAtural Course and Prognosis of PFIC 
and Effect of Biliary Diversion (NAPPED). 
As an example, if the expected proportion with at least one event is estimated to be 30% in the 
study population, and then if the proportion of patients with at least one event during A4250 
long-term treatment are shown to be only 10% in the study, the power is approximately 89% 
to 96% (1-sided test, alpha=2.5%) for a confidence interval (CI) with upper boundary <30% 
based on a sample size of n=48 to 60. The sample size of 60 patients for Cohort 2 was estimated 
based on the availability of target patient population to evaluate the therapeutic benefit for those 
patients. 
11.2 
Statistical Methods 
11.2.1 
Statistical Analysis Sets 
Full Analysis Set 
The full analysis set (FAS) will consist of all patients who received at least 1 dose of study 
drug in Study A4250-008. The FAS will be the primary analysis set for all analyses unless 
otherwise specified. 
11.2.2 
Methods of Statistical Analyses 
11.2.2.1 
General Principles 
Descriptive statistics will mainly be used in this open-label extension study. Patients with BRIC 
will be presented separately in efficacy assessments. All statistical analyses will be performed 
using SAS version 9.3 or higher. 
The primary analysis will be performed after the last patient (from Cohort 1 or 2) completes 
the 72-week treatment period. Analyses during the extension period will consist of safety 

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summaries and other evaluations on an ongoing basis per the schedule of assessment for the 
extension period. 
Baseline 1 will be defined as the last value prior to treatment start in Study A4250-005 for 
Cohort 1 patients.
Baseline 2 will be defined as the last value prior to treatment start in Study A4250-008 for all 
patients. Baseline 2 will be used in all analyses unless otherwise specified.
Descriptive statistics will be summarized for Cohort 1, Cohort 2 excluding BRIC, Cohort 2 
BRIC, and combined Cohort 1 + Cohort 2 excluding BRIC. Within Cohort 1, the following 
subgroups will be presented: ‘A4250 40 µg/kg/day (-005) to 120 µg/kg/day (-008)’, ‘A4250
120 µg/kg/day (-005) to 120 µg/kg/day (-008)’, ‘A4250 40 µg/kg/day (-005) and 120 µg/kg/day
(-005) to 120 µg/kg/day (-008)’, and ‘placebo (-005) to 120 µg/kg/day (-008)’. Within Cohort
2 excluding BRIC, 3 subgoups (‘40 µg/kg/day’, ‘40 µg/kg/day to 120 µg/kg/day’, and ‘120 
µg/kg/day’) will be presented. Cohort 1 Placebo to A4250 120 µg/kg/day will also be
combined with Cohort 2 excluding BRIC for presentations. 
11.2.2.2
Missing Data
Missing data will be reported descriptively. In general, imputations of missing observations 
will not be made. Any additional sensitivity analysis concerning missingness and details 
regarding handling of missing data will be described in the statistical analysis plan (SAP).
Continued collection of efficacy data for patients who discontinue treatment will be made as 
far as possible.
11.2.2.3
Demographic and Baseline Characteristics
For Cohort 1, descriptive summaries of demographics and other baseline characteristics 
(including medical and surgical history) will be presented overall using the FAS. For Cohort 2, 
descriptive summaries of demographics and other baseline characteristics will be presented 
overall for the full analysis set as well as by the underlying diagnostics subgroups. 
Prior medication will be summarized overall using the full analysis set.
11.2.2.4
Subject Disposition
The following will be summarized overall by Cohort:
Patients enrolled (who signed the informed consent)
Patients treated
Patients completing treatment
Patients discontinuing treatment and reason 
Patients completing the study
Patients withdrawing early (including withdrawal reason)

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Additionally, patients enrolled, included in the FAS will be summarized by region by Cohort.
11.2.2.5
Evaluation of Primary Efficacy Variables
The proportion of positive pruritus assessments at the patient level over the 72-week 
treatment period will be summarized. A positive pruritus assessment is defined as a 
-point drop from baseline on the Albireo ObsRO 
instrument. At each assessment, the AM score will be compared to the baseline AM average, 
and the PM score will be compared to the baseline PM average. Both AM and PM pruritus 
assessments will be included in the analysis of this endpoint. Baseline will be defined as the 
average score from 14 days prior to treatment start in Study A4250-008 for AM and PM, 
respectively.
Fasting serum bile acids baseline will be calculated as the average of the pre-dose value in 
Study A4250-008 (Visit 1) and the previous visit (Visit 8 in study A4250-005) for Cohort 1. 
Fasting serum bile acids baseline will be calculated as the average of Visit S-2 and the pre- 
dose Visit 1 values in Study A4250-008 for Cohort 2. The end value is the average of the 
values at Weeks 70 and 72 in study A4250-008. 
The change from baseline over the Treatment Period in serum bile acids will be analyzed 
mainly by using descriptive statistics. Change over time will also be displayed using 
graphical presentations (e.g., a spaghetti plot which illustrates the change in both Study 
A4250-005 and Study A4250-008 by treatment group in Study A4250-005). In addition, 
change from baseline 1 to end of treatment will be analyzed by using one-sample T-test or 
Wilcoxon signed-rank test as appropriate.
As an exploratory analysis of pruritus and serum bile acids, a comparison of treatment with 
A4250 120 µg/kg/day during the first 24 weeks of Study 008 vs placebo patients over the 24- 
week treatment period from Study 005 will be carried out. 
11.2.2.6
Evaluation of Secondary and Exploratory Efficacy Variables
All secondary and exploratory variables listed under Sections 9.1.2 and 9.1.3 will be analyzed 
descriptively for categorical and continuous data, as applicable. For continuous data, the
change from baseline will be analyzed in addition to the actual visit values. For categorical 
data, shift tables or frequency and percentages of patients will be presented as appropriate.
Change in growth (Z-score, SD from P50 standard growth curve) will be analyzed by using
one-sample T-test or Wilcoxon signed-rank test as appropriate.
Change in growth
(height/length for age, weight for age, BMI, and mid-arm circumference) will also be displayed 
using graphical presentations.
A 95% CI will be calculated for the proportion of patients experiencing surgical bile diversion 
or liver transplantation or death as well as for the proportion of patients experiencing surgical 
bile diversion or death or liver transplantation. The upper boundary will be compared to the

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expected proportion of events, using the event probability estimated from the untreated 
reference population in an ongoing observational cohort study. 
Time to first event, i.e., time to surgical bile diversion or liver transplantation or death, will be 
explored by descriptive statistics and Kaplan-Meier curves, which also will be used to make a 
comparison to the NAPPED population. The propensity score matched cohort analysis using 
inverse probability of treatment weights will be used to match the study patient population to
the reference population based on age group and PFIC type. 
11.2.2.7
Evaluation of Safety Variables
Safety data will be analyzed using descriptive statistics and summaries overall of SAEs, AEs, 
vital signs, clinical laboratory tests (hematology, clinical chemistry and urinalysis) and 
concomitant medication. Analyses will be performed using the full analysis set.
Summaries of AEs (coded according to the Medical Dictionary for Regulatory Activities 
(MedDRA) system organ class and MedDRA preferred term) will include: 
Overview of the incidence of TEAEs (TEAEs, Drug-related TEAEs, TEAEs leading to 
study discontinuation, and Treatment-emergent SAEs)
TEAEs by system organ class (SOC) and preferred term
 
Intensity of TEAEs by SOC and preferred term 
Drug-related TEAEs by SOC and preferred term
TEAEs leading to study discontinuation by SOC and preferred term 
Treatment-emergent SAEs by SOC and preferred term
Concomitant medication use during the Treatment Period will be summarized by Anatomical 
Therapeutic Chemical (ATC) class and World Health Organization (WHO) preferred name.
Summaries of vital signs will be presented. For each visit, the actual results and the change 
from baseline, and the number and percentage of patients with potentially clinically significant 
(PCS) values observed post-baseline will be presented.
Summaries of clinical safety laboratory data will be presented. For each visit, the actual result 
and the change from baseline, and the number and percentage of patients with PCS values 
observed post-baseline will be presented.
Data listings will be provided for each patient for all safety parameters.
11.2.2.8
Compliance and Exposure
Exposure will be analyzed by calculating the number of days with exposure to study drug. For 
Cohort 2 patients who dose escalate from 40 µg/kg/day to 120 µg/kg/day, exposure in each
dose and overall will be calculated. Results will be presented overall using the full analysis 
set.

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The percentage compliance will be described overall, and the number of patients with a 
A summary of patients who down-titrated from 120 µg/kg/day to 40 µg/kg/day during the study 
will be presented as well.
11.2.3
Interim Analysis
Analyses may be performed at select time points throughout the collection of patient data for 
regulatory requirements and sponsor decision making purposes. 
11.2.4
Data Safety Monitoring Board
A DSMB consisting of sponsor-independent clinical experts and sponsor-independent
statistical expert(s) will be established for Study A4250-005, and continue for this study until 
the last patient completes the 72-week treatment period. The DSMB will periodically 
(approximately on a quarterly basis) meet for the review of accumulating study data, including 
safety (AE and laboratory data), and liver values. 
The DSMB will make recommendations for the remaining part of the study (further details will 
be provided in the DSMB charter). The DSMB may recommend continuing with the study as 
planned or stopping the study early for safety reasons.
The DSMB will submit its 
recommendations in writing to Albireo Medical/ICON who are responsible for responding to
the recommendations of the DSMB and taking appropriate action. The investigators will only 
be informed by Albireo Medical/ICON if the study requires a protocol amendment or is
stopped. The DSMB may choose to make additional evaluations at any time if they feel this is 
warranted from a safety point of view. 
The DSMB will act according to its own written standard operating procedure described in a 
charter and will prepare written minutes of its meetings. The charter of the DSMB will be 
stored in the Trial Master File. The DSMB will maintain records of its meetings and these will 
become part of the study file when the study is complete.

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12 
DIRECT ACCESS TO SOURCE DATA/NOTES 
The investigator/institution shall provide direct access to source data/documents for 
study-related monitoring, audits, IEC/IRB review and regulatory inspection. 

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13 
QUALITY CONTROL AND QUALITY ASSURANCE 
13.1 
Conduct of the Study 
Albireo/ICON shall implement and maintain quality control and quality assurance procedures 
with written standard operating procedures to ensure that the study is conducted and data are 
generated, documented, and reported in compliance with the protocol, Good Clinical Practice 
(GCP) and applicable regulatory requirements. 
This study shall be conducted in accordance with the provisions of the Declaration of Helsinki 
(October 1996) and all revisions thereof, and in accordance with US FDA regulations (Code 
of Federal Regulations, Sections 312.50 and 312.56) and with International Council for 
Harmonisation (ICH) GCP (EMA/CHMP/ICH/135/1995), as applicable. 
The investigator may not deviate from the protocol without a formal protocol amendment 
having been established and approved by the competent authority, as applicable, and IEC/IRB 
approval, except when necessary to eliminate immediate hazards to the patient or when the 
change(s) involve(s) only logistical or administrative aspects of the study. Any deviations may 
result in the patient having to be withdrawn from the study and render that patient 
non-evaluable. 
13.2 
Study Monitoring 
Before study initiation, at a site initiation visit or at an investigator’s meeting, an Albireo 
representative or designee will review the protocol and eCRF with the investigators and the 
investigative staff. During the study, the clinical monitor (clinical research associate [CRA]) 
will visit the site regularly to check the completeness of patient records, the accuracy of entries 
on the eCRFs, the adherence to the protocol and to GCP, the progress of enrollment, and to 
ensure that study drug is being stored, dispensed, and accounted for according to specifications. 
The investigator must ensure that eCRFs are completed within a timely period of the patient 
visits, as per individual site agreements, and must allow the CRA and Albireo representative 
or designee periodic access to patient records and all study-related materials, including relevant 
hospital or clinical records, to confirm their consistency with the eCRF entries. No information 
in these records about the identity of the patients will leave the study center. Albireo 
monitoring standards require full verification for the presence of the signed ICF, adherence to 
the inclusion/exclusion criteria, documentation of SAEs, and recording of primary efficacy and 
safety variables. The CRA will review source data compared with the eCRFs and will verify 
source data according to the study-specific monitoring plan. The design of the study, the 
frequency of patient visits, and the site enrollment rate will determine the frequency of 
monitoring visits. Upon study completion, the CRA will visit the site to conduct a study 
termination visit, which will include collection of any outstanding documentation. 

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Remote monitoring practices may be employed in accordance with the country/institution 
specific guidelines in circumstances where an on-site monitoring visit is not feasible (i.e., 
COVID-19). 
It is recommended that the investigator/investigative staff log into the eCRF system every 
working day or at minimum twice weekly in order to provide a prompt response to queries. 
The investigator/investigative staff should respond to queries and make any relevant changes 
to the study data within 3 working days. 

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14 
ETHICS 
14.1 
Independent Ethics Committee/Institutional Review Board 
Prior to the start of the study, the investigator is responsible for ensuring that the protocol and 
informed consent form (ICF) have been reviewed and approved by the applicable IEC/IRB and 
competent authority. The IEC/IRB shall be appropriately constituted and perform its functions 
in accordance with US FDA, ICH GCP and/or local requirements, as applicable. 
The IEC/IRB and regulatory authority (competent authority), as applicable, shall approve all 
protocol amendments (except for logistical or administrative changes), written informed 
consent 
documents 
and 
document 
updates, 
patient 
recruitment 
procedures 
(e.g., 
advertisements), written information to be provided to the patients, IB, available safety 
information, information about payment and compensation available to patients and caregivers, 
the investigator's curriculum vitae and/or other evidence of qualifications and any other 
documents requested by the IEC/IRB or competent authority. 
14.2 
Written Informed Consents and Assents 
The investigator (physician) or investigative staff, as according to local regulation, will explain 
to each patient (or legally authorized representative) the nature of the study, its purpose, the 
procedures involved, the expected duration, alternative treatment, the potential risks and 
benefits involved, and any discomfort that may occur. Each caregiver/patient will be informed 
that participation in the study is voluntary and that he/she or their child may withdraw from the 
study at any time and that withdrawal of consent will not affect his/her subsequent medical 
treatment or relationship with the treating physician. 
Caregivers/patients will be informed that they/their children may experience side-effects or be 
at risk for symptoms, illnesses, or complications that cannot be foreseen by Albireo. As with 
other medications, people treated with A4250 may be at risk of developing allergic reactions 
or anaphylaxis. Caregivers/patients will be advised that study procedures include regular blood 
sampling for measurement of safety parameters and biological markers and that some minor 
risks are associated with these procedures. 
This informed consent should be given by means of a signed ICF, written in non-technical 
language in accordance with applicable GCP, the Declaration of Helsinki, and regulatory 
authorities. The caregiver(s)/patient should read and consider the statements before signing 
and dating them and should be given a copy of each signed document. If written consent is not 
possible, oral consent can be obtained if witnessed and followed by a signed statement from 
one or more persons not involved in the study, indicating why the patient was unable to sign 
the form. No patient can enter the study before his/her or caregiver(s), as required by country 
regulation, informed consent has been obtained. 
The ICF must be submitted by the investigator/investigative staff with the protocol to the 
applicable IEC/IRB for review and approval. Albireo will supply an ICF which complies with 

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regulatory requirements and country laws and is considered appropriate for the study. Any 
changes to the ICF suggested by the investigator must be agreed to by Albireo before 
submission to the IEC and a copy of the approved version must be provided to the clinical 
monitor after IEC approval. 

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15 
DATA HANDLING AND RECORD KEEPING 
15.1 
Case Report Forms/Source Data Handling 
The investigator shall be provided with standardized eCRFs and shall ensure that all data from 
patient visits are promptly entered into the eCRFs in accordance with the specific instructions 
given. The investigator must sign each completed eCRF, verifying the accuracy and integrity 
of the data recorded. 
A list of the normal ranges for all laboratory tests to be undertaken forms part of the 
documentation to be collated prior to study start. As a central laboratory has been selected to 
conduct any or all tests, it is essential that all samples be analyzed at the central laboratory. 
The investigator must maintain source documents such as laboratory reports, consultation 
reports, and complete medical history and physical examination reports. 
As no ethnicity data can be collected in the source document for study sites in France, the eCRF 
will be the Source Document for “origines ethniques”. 
15.2 
Retention of Essential Documents 
Essential documents, as defined by ICH GCP, include: the signed protocol and any 
amendment(s); copies of the completed eCRFs (for site archiving, compact discs of eCRF data 
for participating patients will be provided); signed ICFs; hospital records and other source 
documents; IEC/IRB approvals, including the associated documents, and all related 
correspondence; drug accountability records; study correspondence; and a list of patients’ 
names and addresses. 
The investigator/investigative staff must retain copies of these essential documents for the 
minimal period specified by ICH GCP and/or by applicable regulatory requirements 
(whichever is longer). The investigator/investigative staff will inform Albireo of the location 
where the essential documents are stored and must contact Albireo for approval before 
disposing of any essential documents. The investigator/investigative staff should take 
measures to prevent accidental or premature destruction of these documents. 

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16 
FINANCING AND INSURANCE 
Financing and insurance are addressed in a separate agreement. 

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17 
PUBLICATION POLICY 
Albireo will retain the ownership of all data. When the study is complete, Albireo shall arrange 
the analysis, tabulation of data and preparation of a clinical study report. Albireo may also use 
the data for publication, presentation at scientific meetings and submission to regulatory 
authorities. All proposed publications based on this study must be subject to the sponsor’s 
approval requirements. 

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18
REFERENCE LIST
1. A4250 Investigator’s Brochure.
2. Alissa FT, Jaffe R, Shneider BL. Update on progressive familial intrahepatic cholestasis. J 
Pediatr Gastroenterol Nutr. 2008;46(3):241-52. 
3. Bull LN, Thompson RJ. Progressive Familial Intrahepatic Cholestasis. Clin Liver Dis. 2018 
Nov;22(4):657-669.
4. Davit-Spraul A, Gonzales E, Baussan C, et al. Progressive familial intrahepatic cholestasis. 
Orphanet J Rare Disease 2009;4:1-12. 
5. Gomez-Ospina N, Potter CJ, Xiao R, et al. Mutations in the nuclear bile acid receptor FXR 
cause progressive familial intrahepatic cholestasis. Nat Commun. 2016 Feb 18;7:10713. 
6. Hofmann AF. The enterohepatic circulation of bile acids in mammals: form and functions. 
Front Biosci (Landmark Ed). 2009 Jan 1;14:2584-98. 
7. Hori T, Justin H, Nguyen JH and Uemoto S. Progressive familial intrahepatic cholestasis. 
Hepatobiliary pancreat Dis Int. 2010; 9(6):570-8. 
8. Jacquemin E. Progressive familial intrahepatic cholestasis. Genetic basis and treatment.
Clin Liver Dis. 2000 Nov;4(4):753-63. 
9. Miethke AG, Zhang W, Simmons J, et al. Pharmacological inhibition of ASBT changes 
bile composition and blocks progression of sclerosing cholangitis in mdr2 knockout mice. 
Hepatology. 2016 February; 63(2):512-23. 
10. Murray CS, Rees JL. Are subjective accounts of itch to be relied on? The lack of relation 
between visual analogue itch scores and actigraphic measures of scratch. Acta Derm 
Venereol. 2011;91(1):18-23. 
11. Pawlikowska L, Strautnieks S, Jankowska I. et al. Differences in presentation and 
progression between severe FIC1 and BSEP deficiencies, J Hepatol. 2010; 53(1):170-8. 
12. Shneider BL, Magee JC, Bezerra JA, et al. Efficacy of fat-soluble vitamin supplementation 
in infants with biliary atresia. Pediatrics, 2012;130(3):e607-14. 
13. Stapelbroek JM, van Erpecum KJ, Klomp LW, Houwen RH. Liver disease associated with 
canalicular transport defects: current and future therapies. J Hepatol. 2010 Feb;52(2):258- 
71.
14.
Mechanisms  to  Clinical  Implications.  Can  J  Gastroenterol  Hepatol.  2018  Jul 
26;2018:2313675.
15. Strubbe B, Geerts A, Van Vlierberghe H, Colle I. Progressive familial intrahepatic 
cholestasis and benign recurrent intrahepatic cholestasis: a review. Acta Gastroenterol 
Belg. 2012 Dec;75(4):405-10. 

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16. Suchy FJ. “Approach to the Infant With Cholestasis.” Liver Disease in Children. Ed. 
Frederick J. Suchy. New York: Cambridge University Press; 2007 179-189. Print. 
17. Venkat VL, Shneider BL, Magee JC, et al. Total Serum Bilirubin Predicts Fat-Soluble 
Vitamin Deficiency Better Than Serum Bile Acids in Infants with Biliary Atresia. J Pediatr 
Gastroenterol Nutr. 2014;59(6):702-7. 
18. Vitale G, Gitto S, Vukotic R, et al. Familial intrahepatic cholestasis: New and wide 
perspectives. Dig Liver Dis. 2019 Jul;51(7):922-33. 
19. Whitington PF, Whitington GL. Partial external diversion of bile for the treatment of 
intractable 
pruritus 
associated 
with 
intrahepatic 
cholestasis. 
Gastroenterology. 
1988;95(1):130-6. 

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19 
APPENDICES 
Appendix 1 
Concomitant Medication Guidelines 

 
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Appendix 2 
Diary Questions including Albireo Patient-Reported 
Outcomes/Observer-Reported Outcome Instrument 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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Page 1 of 2 
 
 
 
Appendix 2: Diary Questions including Albireo Patient-Reported 
Outcomes/Observer-Reported Outcome Instrument 
Patient-Reported Outcome 
 
Morning Diary (to be completed shortly after waking each morning) 
Please answer the questions on the following screens. There are no right or wrong answers. Please 
think about the time since you went to bed last night (beginning when you started trying to fall 
asleep). 
1. How bad was your worst itching since you 
went to bed last night? 
 
2. How hard was it to fall asleep last night 
because of your itching? 
 
3. How hard was it to stay asleep last night 
because of your itching? 
 
4.  Did you wake up last night because of 
itching? 
No / Yes 
5.  How tired do you feel this morning? 
 
 
 
Bedtime Diary (to be completed when going to bed each night) 
Please answer the questions on the following screens. There are no right or wrong answers. Please 
think about the time since you woke up this morning. 
1. How bad was your worst itching since you 
woke up this morning? 
 
2. How tired were you since you woke up this 
morning? 
 

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Observer Reported Outcome 
 
Morning Diary (to be completed shortly after child wakes up each morning) 
Please answer the questions on the following screens. There are no right or wrong answers. Please 
think about the time since your child went to bed last night (beginning when your child started trying 
to fall asleep). As a reminder, when we use the term “scratching,” we would like you to think about all 
of the different types of scratching behaviors that you can see. 
1. How bad was your child’s worst scratching 
since he/she went to bed last night? 
 
2.  Since your child went to bed last night, did 
you see blood due to scratching? 
No / Yes 
3. Did your child need a caregiver to help 
him/her fall asleep last night due to his/her 
itching? 
No / Yes 
4. Did your child need a caregiver to soothe 
him/her at some time during the night last 
night due to his/her itching? 
No / Yes 
5.  Did your child need a caregiver to sleep 
with him/her at some time during the night 
last night due to his/her itching? 
No / Yes 
6. How many times did you notice that your 
child woke up last night? 
0-99 
7. Did your child take any prescribed or over- 
the-counter medicines before going to bed 
last night that may have made him/her 
sleepy? 
No / Yes 
 
 
Bedtime Diary (to be completed when child is going to bed each night) 
Please answer the questions on the following screens. There are no right or wrong answers. Please 
think about the time since your child woke up this morning. As a reminder, when we use the term 
“scratching,” we would like you to think about all of the different types of scratching behaviors that 
you can see. 
1. How bad was your child’s worst scratching 
since he/she woke up this morning? 
 
2.  How tired did your child seem to be today? 
 

 
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Appendix 3 
Patient Global Impression of Change (PGIC) and Patient Global 
Impression of Symptoms (PGIS) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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Page 1 of 4
Appendix 3: Patient Global Impression of Change (PGIC) and Patient Global 
Impression of Symptoms (PGIS)
ITCH
PGIC – CHILD
Please pick the answer below that best describes the overall change in your itch since you started 
taking the study medicine.
Very much better 
Much better
A little better 
No change
A little worse 
Much worse
Very much worse
PGIC – PARENT
Please choose the response below that best describes the overall change in your child’s
scratching since he/she started taking the study medication.
Very much better 
Moderately better 
A little better
No change
A little worse
Moderately worse 
Very much worse
PGIC – CLINICIAN
Please choose the response below that best describes the overall change in your patient’s 
scratching since he/she started taking the study medication.
Very much better 
Moderately better 
A little better
No change
A little worse
Moderately worse 
Very much worse

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PGIS – CHILD
Please choose the answer below that best describes how bad your itch has been the past week.
None
A little
Medium 
Bad
Very Bad
PGIS – PARENT
Please choose the response below that best describes the severity of your child’s scratching over 
the past week.
None 
Mild
Moderate 
Severe
Very Severe
PGIS – CLINICIAN
Please choose the response below that best describes the severity of your patient’s scratching 
over the past week.
None 
Mild
Moderate 
Severe
Very Severe

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SLEEP
PGIC – CHILD
Please choose the answer below that best describes the overall change in your sleep problems 
since you started taking the study medicine.
Very much better 
Much better
A little better 
No change
A little worse 
Much worse
Very much worse
PGIC – PARENT
Please choose the response below that best describes the overall change in your child’s sleep
problems since he/she started taking the study medication.
Very much better 
Moderately better 
A little better
No change
A little worse
Moderately worse 
Very much worse
PGIC – CLINICIAN
Please choose the response below that best describes the overall change in your patient’s sleep 
problems since he/she started taking the study medication.
Very much better 
Moderately better 
A little better
No change
A little worse
Moderately worse 
Very much worse
PGIS – CHILD
Please choose the answer below that best describes how bad your sleep problems have been 
over the past week.
None
A little
Medium 
Bad

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Very Bad
PGIS – PARENT
Please choose the response below that best describes the severity of your child’s sleep problems 
over the past week.
None 
Mild
Moderate 
Severe
Very Severe
PGIS – CLINICIAN
Please choose the response below that best describes the severity of your patient’s sleep 
problems over the past week.
None 
Mild
Moderate 
Severe
Very Severe

 
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Appendix 4 
Pediatric Quality of Life Inventory (PedQL) Questionnaire 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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PedsQL 4.0 - Parent (2-4) 
01/00 
Not to be reproduced without permission 
Copyright © 1998 JW Varni, Ph.D. All rights reserved 
PedsQL-4.0-Core-PT - United States/English – Original version 
PedsQL-4.0-Core-PT_AU4.0_eng-USori 
 
 
DIRECTIONS 
On the following page is a list of things that might be a problem for your child. 
Please tell us how much of a problem each one has been for your child 
during the past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
 
PedsQL 
™
™ 
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee 
IInnvveennttoorryy 
Version 4.0 
 
 
PARENT REPORT for TODDLERS (ages 2-4) 
 
 
 
ID#  
 
Date: 
 

 
 
 
How much of a problem is this for you? 
 
 
Not at all 
Sometimes 
A lot 
© 
© 
® 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
PedsQL 4.0 - (5-7) 
01/00 
Not to be reproduced without permission 
Copyright© 1998 JW Varni, Ph.D. All rights reserved. 
PedsQL-4.0-Core - United States/English - Original version 
PedsQL-4.0-Core-YC_AU4.0_eng-USori 

PedsQL 4.0 - Parent (5-7) 
01/00 
Not to be reproduced without permission 
Copyright © 1998 JW Varni, Ph.D. All rights reserved 
PedsQL-4.0-Core-PYC – United States/English – Original version 
PedsQL-4.0-Core-PYC_AU4.0_eng-USori 
 
 
DIRECTIONS 
On the following page is a list of things that might be a problem for your child. 
Please tell us how much of a problem each one has been for your child 
during the past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
 
PedsQL 
™
™ 
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee 
IInnvveennttoorryy 
Version 4.0 
 
 
PARENT REPORT for YOUNG CHILDREN (ages 5-7) 
 
 
 
ID#  
 
Date: 
 

PedsQL 4.0 - (8-12) 
01/00 
Not to be reproduced without permission 
Copyright © 1998 JW Varni, Ph.D. All rights reserved 
PedsQL-4.0-Core-C – United States/English – Original version 
PedsQL-4.0-Core-C_AU4.0_eng-USori 
 
 
DIRECTIONS 
On the following page is a list of things that might be a problem for you. 
Please tell us how much of a problem each one has been for you 
during the past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
 
PedsQL 
™
™ 
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee 
IInnvveennttoorryy 
Version 4.0 
 
 
CHILD REPORT (ages 8-12) 
 
 
 
ID#  
 
Date: 
 

PedsQL 4.0 - Parent (8-12) 
01/00 
Not to be reproduced without permission 
Copyright © 1998 JW Varni, Ph.D. All rights reserved 
PedsQL-4.0-Core-PC – United States/English – Original version 
PedsQL-4.0-Core-PC_AU4.0_eng-USori 
 
 
DIRECTIONS 
On the following page is a list of things that might be a problem for your child. 
Please tell us how much of a problem each one has been for your child 
during the past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
 
PedsQL 
™
™ 
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee 
IInnvveennttoorryy 
Version 4.0 
 
 
PARENT REPORT for CHILDREN (ages 8-12) 
 
 
 
ID#  
 
Date: 
 

PedsQL 4.0 - Parent (13-18) 
01/00 
Not to be reproduced without permission 
Copyright © 1998 JW Varni, Ph.D. All rights reserved 
PedsQL-4.0-Core-PA – United States/English – Original version 
PedsQL-4.0-Core-PA_AU4.0_eng-USori 
 
 
DIRECTIONS 
On the following page is a list of things that might be a problem for your teen. 
Please tell us how much of a problem each one has been for your teen 
during the past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
 
PedsQL 
™
™ 
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee 
IInnvveennttoorryy 
Version 4.0 
 
 
PARENT REPORT for TEENS (ages 13-18) 
 
 
 
ID# 
 
Date: 
 

PedsQL 4.0 - (13-18) 
01/00 
Not to be reproduced without permission 
Copyright © 1998 JW Varni, Ph.D. All rights reserved 
PedsQL-4.0-Core-A – United States/English – Original version 
PedsQL-4.0-Core-A_AU4.0_eng-USori 
 
 
DIRECTIONS 
On the following page is a list of things that might be a problem for you. 
Please tell us how much of a problem each one has been for you 
during the past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
 
PedsQL 
™
™ 
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee 
IInnvveennttoorryy 
Version 4.0 
 
 
TEEN REPORT (ages 13-18) 
 
 
 
ID#  
 
Date: 
 

PedsQL 4.0 - (18-25) 
2/07 
Not to be reproduced without permission 
Copyright © 1998 JW Varni, Ph.D. All rights reserved 
PedsQL-4.0-Core-Yad – United States/English – Original version 
PedsQL-4.0-Core-Yad_AU4.0_eng-USori 
 
 
DIRECTIONS 
On the following page is a list of things that might be a problem for you. 
Please tell us how much of a problem each one has been for you 
during the past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
PedsQL
™
™
 
YYoouunngg AAdduulltt Q
Quuaalliittyy ooff LLiiffee 
IInnvveennttoorryy 
Version 4.0 
 
 
YOUNG ADULT REPORT (ages 18-25) 
 
 
 
ID#  
 
Date: 
 

Copyright © 1998 JW Varni, PhD. 
PedsQL 2.0 - Parent Family Impact 
06/04 
Not to be reproduced without permission 
PedsQL-2.0-FIM - United States/English – Original version 
PedsQL-2.0-FIM_AU2.0_eng-USori 
 
 
DIRECTIONS 
Families of children sometimes have special concerns or difficulties because of the 
child’s health. On the following page is a list of things that might be a problem for 
you. Please tell us how much of a problem each one has been for you during the 
past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
 
PedsQL
™
 
Family Impact Module 
Version 2.0 
 
 
PARENT REPORT 
 
 
 
ID# 
 
Date: 
 

 
A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
 
 
Appendix 5 
Guideline for Fat-Soluble Vitamin Supplementation 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confidential 
 
Amendment 6.1 UK, 11 February 2022 
 
120 

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Confidential
Amendment 6.1 UK, 11 February 2022
Page 1 of 2
Appendix 5: Guideline for Fat-Soluble Vitamin Supplementation
Cholestasis predisposes to fat-soluble vitamin deficiencies. Fat-soluble vitamin levels, 
i.e., vitamins A and E, 25-hydroxy vitamin D, and INR (surrogate for vitamin K) are 
measured routinely during the study. If a patient has any fat-soluble vitamin level(s) that 
are out of range, vitamin supplementation adjustments may be required. Below are 
suggested guidelines for fat-soluble vitamin deficiency treatment [Venkat 2014; Shneider
2012]. Additional patient monitoring and/or treatment strategies may be warranted at the 
discretion of the investigator.
Target Fat-soluble Vitamin Levels and Replacement Regimens
Vitamin
Target Range 
(Serum Level)
Supplementation Strategy
A (retinol)
19 to 77 µg/dL* 
retinol:retinol-binding 
protein molar ratio > 0.8 
Increments of 5000 IU (up to 25,000 
to 50,000 IU/day) orally or monthly 
intramuscular administration of 
50,000 IU**
D (25-hydroxy 
vitamin D)
15 to 45 ng/mL*
Increments of 1200 to 8000 IU 
orally daily of cholecalciferol or 
ergocalciferol; alternatively
calcitriol at 0.05 to 0.2 µg/kg/day*
tocopherol)
3.8 to 20.3 µg/mL 
vitamin E:total serum 
lipids ratio >0.6 mg/g
Increments of 25 IU/kg of
d- -tocopheryl polyethylene glycol 
– 1000 succinate (TPGS) orally 
daily (to 100 IU/kg/day)
K (phytonadione)
INR 1.2
1.2 <INR 1.5: 2.5 mg
vitamin K orally daily
1.5 <INR 1.8: 2.0 to 5.0 mg
vitamin K intramuscular and
2.5 mg vitamin K orally daily
INR >1.8: 2.0 to 5.0 mg vitamin 
K intramuscular and 5.0 mg 
vitamin K orally daily
*Clinical practice may vary. This is meant as a guidance only and does not override local standard of care. Investigators
should provide best case practices for management and treatment

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.1 UK, 11 February 2022 
Page 2 of 2 
 
 
 
** For further detail regarding age related Tolerable Upper Intake (UL) for preformed vitamin A please refer to page 163 in 
the European Food Safety Authority guidance: Tolerable Upper Intake Levels for Vitamins and Minerals; Scientific Committee 
on food Scientific Panel on Dietetic Products, Nutrition and Allergies 
http://www.efsa.europa.eu/sites/default/files/efsa_rep/blobserver_assets/ndatolerableuil.pdf 

 
A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
 
 
Appendix 6 
Contraceptive Requirements 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confidential 
 
Amendment 6.1 UK, 11 February 2022 
 
123 

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Confidential
Amendment 6.1 UK, 11 February 2022
Page 1 of 2
Appendix 6: Contraceptive Requirements
A woman is considered of childbearing potential (WOCBP), i.e. fertile, following 
menarche and until becoming post-menopausal unless permanently sterile. Permanent 
sterilisation methods include hysterectomy, bilateral salpingectomy and bilateral 
oophorectomy.
Contraceptive methods, or combinations of contraceptive methods, for males and females 
that can achieve a failure rate of less than 1% per year when used consistently and 
correctly are considered as highly effective birth control methods and must be used at 
least to up to 90 days following the last day of treatment. 
Such methods include:
Combined (estrogen and progestogen containing) hormonal contraception 
associated with inhibition of ovulation:
o oral
o intravaginal
o transdermal
Progestogen-only hormonal contraception associated with inhibition of ovulation:
o oral
o injectable
o implantable
Intrauterine device (IUD)
Intrauterine hormone-releasing system (IUS) 
Bilateral tubal occlusion
Vasectomised partner 
 
Sexual abstinence 
Sexual abstinence is considered a highly effective method only if defined as refraining 
from heterosexual intercourse during the entire study period up to at least 90 days after 
the last day of treatment. The reliability of sexual abstinence needs to be evaluated in 
relation to the duration of the clinical trial and the preferred and usual lifestyle of the 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 6.1 UK, 11 February 2022 
Page 2 of 2 
 
 
 
subject. Periodic abstinence (e.g., calendar, ovulation, symptothermal, post-ovulation 
methods) and withdrawal are not acceptable methods of contraception. 
Requirements according to “Recommendations related to contraception and pregnancy 
testing in clinical trials”, HMA CTFG (Clinical Trial Facilitation Group), 2014 

 
A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
 
 
Appendix 7 
Blood Volumes 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confidential 
 
Amendment 6.1 UK, 11 February 2022 
 
126 

ICON Central Laboratories 
Scientific Affairs 
Estimated Blood Volume Request 
Version: 15.0 
Protocol#: A4250-008 
SPONSOR: Albireo 
Age Group 0 months to 30 years of age 
Estimated Blood Volume Request (MS Excel) 
Eff. 25 October 2011, Vs. 1 
QS#: MA706App105 
Page 3 of 3 
 
 
Visit^ 
Testing^1-9 
Tube 
volume 
(mL) 
Tube 
Type 
# of 
Collection 
Tubes 
# of 
Aliquots 
Volume 
(mLs) 
Volume/ 
visit 
(mL) 
Volume/
visit 
(tsp) 
Volume/ 
visit 
(TBS) 
#5. Autotaxin serum samples will be tested at LGC 
#6. For subjects requiring optional pregnancy testing, collect 1.1 mL SST 
#7. Optional Sample. Only collected if required 
#8. Collection requirements for Extension Period Visit added per provision of schedule of assessments provided by sponsor for utiliztion in an upcoming revised protocol. 
#9. For patients who experience a hepatic adverse event and/or hepatic decompensation, collect 1.1. mL Plasma for PK 
 
Created by: Jennifer Rodriguez, Protocol Review 
Date: 19-Mar-2020 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 06, 21 December 2021 
1 
 
 
 
CLINICAL STUDY PROTOCOL A4250-008 
An Open-label Extension Study to Evaluate Long-term Efficacy and Safety of A4250 in 
Children with Progressive Familial Intrahepatic Cholestasis Types 1 and 2 (PEDFIC 2) 
 
 
IND Number: 
130591 
EudraCT Number 
2017-002325-38 
 
Text Product: 
A4250 
 
Indication: 
Progressive Familial Intrahepatic Cholestasis (PFIC) 
 
Sponsor: 
Albireo AB 
 
Development Phase: 
Phase 3 
 
Sponsor Signatory: 
 Patrick Horn, MD, PhD 
Sponsor Medical Monitor: 
 
Principal Investigator: 
Richard Thompson, MD, PhD 
Date of the Protocol: 
21 December 2021 
Version of the Protocol: 
Amendment 06 
 
 
 
 
 
 
 
 
 
Confidential 
 
The information in this document contains trade secrets and commercial information that are privileged or 
confidential and may not be used, divulged, published, or otherwise disclosed without the written consent of 
Albireo AB. These restrictions on disclosure apply equally to all future information supplied to you or 
generated by you in connection with the study. 
PPD

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 06, 21 December 2021 
2 
 
 
 
 
SPONSOR SIGNATURE PAGE 
PROTOCOL TITLE: An Open-label Extension Study to Evaluate Long-term Efficacy 
and Safety of A4250 in Children with Progressive Familial Intrahepatic Cholestasis 
Types 1 and 2 (PEDFIC 2) 
 
 
PROTOCOL NUMBER: A4250-008 
 
 
Albireo AB 
 
 
Patrick Horn, MD, PhD 
Date (day/month/year) 
PPD

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 06, 21 December 2021 
3 
 
 
 
INVESTIGATOR SIGNATURE PAGE 
 
 
PROTOCOL TITLE: An Open-label Extension Study to Evaluate Long-term Efficacy 
and Safety of A4250 in Children with Progressive Familial Intrahepatic Cholestasis 
Types 1 and 2 (PEDFIC 2) 
 
 
PROTOCOL NUMBER: A4250-008 
I have read this protocol and agree that it contains all necessary details for performing this 
study. I will conduct the study as outlined herein and will complete the study within the time 
designated, in accordance with all stipulations of the protocol and in accordance with Good 
Clinical Practice (GCP), local regulatory requirements, and the Declaration of Helsinki. 
I will provide copies of the protocol and all pertinent information to all individuals responsible 
to me who assist in the conduct of this study. I will discuss this material with them to ensure 
that they are fully informed regarding the study drug and the conduct of the study. 
I will use only the informed consent approved by the Independent Ethics Committee 
(IEC)/Institutional Review Board (IRB) and will fulfil all responsibilities for submitting 
pertinent information to the IEC/IRB responsible for this study. 
I agree that the Sponsor (Albireo AB) shall have access to any source documents from which 
case report form information may have been generated. 
I further agree not to originate or use the name of Albireo AB or A4250 in any publicity, news 
release, or other public announcement, written or oral, whether to the public, press, or 
otherwise, relating to this protocol, to any amendment to the protocol, or to the performance of 
this protocol without the prior written consent of Albireo AB. 
 
 
 
 
 
Name of Investigator 
 
 
 
 
 
Signature 
Date (day/month/year) 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 06, 21 December 2021 
4 
 
 
 
1 
ADMINISTRATIVE INFORMATION 
An Open-label Extension Study to Evaluate Long-term Efficacy and Safety of A4250 in 
Children with Progressive Familial Intrahepatic Cholestasis Types 1 and 2 (PEDFIC 2) 
Protocol No.: 
A4250-008 
Date of the initial Protocol: 
24 August 2017 
Date and Number of Amendment(s): 
Amendment 01, 18 April 2018 
Amendment 02, 18 January 2019 
Amendment 03, 11 March 2019 
Amendment 04, 25 October 2019 
Amendment 05, 18 March 2020 
Amendment 06, 21 December 2021 
Sponsor: 
Albireo AB 
Arvid Wallgrens Backe 20 
413 46 Göteborg 
Sweden 
Clinical Research Organization: 
ICON Clinical Research Ltd 
South County Business Park 
Leopardstown, Dublin 18, 
D18 X5R3 
Ireland 
Sponsor Signatory: 
Patrick Horn, MD, PhD 
Albireo Pharma, Inc. 
10 Post Office Square, Suite 502 South 
Boston, MA 02109 
United States 
Tel 
 
Sponsor Medical Monitor: 
 
Tel 
 
Principal Investigator: 
Richard Thompson, MD, PhD 
SE5 9RS, London 
United Kingdom 
Tel 
Fax
PPD
PPD
PPD
PPD
PPD

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 06, 21 December 2021 
5 
 
 
 
2 
STUDY SYNOPSIS 
 
Name of Sponsor/Company: 
Albireo AB 
Name of Product: 
A4250 
Name of Active Ingredient: 
A4250 
Title of Study: 
An Open-label Extension Study to Evaluate Long-term Efficacy and Safety of A4250 in Children with 
Progressive Familial Intrahepatic Cholestasis Types 1 and 2 (PEDFIC 2) 
Principal Investigator: 
Richard Thompson, MD, PhD 
Study Centers: 
Up to 50 sites will be included in this study in the United States (US), Canada, Europe, Australia, and Middle 
East. 
Publication(s): 
None. 
Planned Study Period: 
Q3 2018 to Q3 2023 
Development Phase: 
Phase 3 
Objectives: 
Primary Objective (Cohort 1) 
To demonstrate a sustained effect of A4250 on serum bile acids and pruritus in children with progressive 
familial intrahepatic cholestasis (PFIC) Types 1 and 2. 
Primary Objective (Cohort 2) 
To evaluate the effect of A4250 on serum bile acids and pruritus in patients with PFIC who either (1) do not 
meet eligibility criteria for Study A4250-005 (PEDFIC 1) or (2) patients who do meet the eligibility criteria 
for Study A4250-005 after recruitment of Study A4250-005 has been completed. 
Secondary Objectives (Cohorts 1 and 2) 
To evaluate the long-term safety and tolerability of repeated daily doses of A4250 
To evaluate the effect of A4250 on growth 
To evaluate the effect of A4250 on biliary diversion and/or liver transplantation 
To evaluate the effect of A4250 on biochemical markers of cholestasis and liver disease 
Methodology: 
This is a Phase 3, multi-center, open-label extension study to investigate the long-term efficacy and safety of a 
120 µg/kg/day daily dose of A4250 in patients with PFIC, including episodic forms also referred to as benign 
recurrent intrahepatic cholestasis (BRIC). Cohort 1 will consist of children with PFIC Types 1 and 2 who have 
participated in study A4250-005. Cohort 2 will consist of approximately 60 patients with PFIC who have 
elevated serum bile acids and cholestatic pruritus and who either (1) do not meet eligibility criteria for Study 
A4250-005 (PEDFIC 1) or (2) are eligible for enrolment in A4250-005 after recruitment of study A4250-005 
has been completed. Up to 40 patients post biliary diversion surgery are allowed to participate in Cohort 2. 
Eligible patients will be enrolled into this open-label extension study and treated with a daily dose of 
40 µg/kg/day1 or 120 µg/kg/day of A4250 for 72 weeks, or 40 µg/kg/day for the first 12 weeks followed by 
120 µg/kg/day for the remaining 60 weeks1. Patients not tolerating the 120 µg/kg/day dose after a minimum 
of 1 week will have the option to down-titrate to a lower dose (40 µg/kg/day). The patient should return to 
the higher dose as soon as deemed appropriate by the investigator. More than one upward dose titration 
(from 40 µg/kg/day directly to 120 µg/kg/day) for the same event is not recommended. Any dose titration 
should be done in consultation with the sponsor Medical Monitor or designee. 
 
1 As of Protocol Amendment 6, patients entering Cohort 2 will start treatment at 40 µg/kg/day with the 
possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus based on 
investigator judgment. 

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Confidential
Amendment 06, 21 December 2021
6
Name of Sponsor/Company:
Albireo AB
Name of Product:
A4250
Name of Active Ingredient:
A4250
Patients who wish to continue receiving A4250 after 72 weeks, will have the option to remain on treatment 
until the drug is commercially available, provided continued use is supported by the risk-benefit profile and 
the subject has not been previously withdrawn or discontinued from the study.
The primary analysis will be performed after the last patient (from Cohort 1 or 2) completes the 72-week 
treatment period. Analyses during the extension period will consist of safety summaries and other evaluations 
on an ongoing basis per the schedule of assessment for the extension period.
Number of Patients:
Approximately 120 patients in total. Approximately 60 patients will be enrolled following participation in 
Study A4250-005 (Cohort 1) and approximately 60 patients will be enrolled directly into this study (Cohort 2).
Diagnosis and Main Criteria for Inclusion:
Cohort 1:
1.
Completion
of
the 24-week
Treatment
Period
of
Study
A4250-005
or withdrawn from 
Study A4250-005 due to patient/caregiver judgment of intolerable symptoms after completing at least 
12 weeks of treatment. Patients who withdraw from A4250-005 due to a study drug related adverse 
event (AE) will not be eligible.
2.
Signed informed consent and assent as appropriate. Patients who turn 18 years of age (or legal age 
per country) during the study will be required to re-consent to remain on the study.
3.
Patients expected to have a consistent caregiver for the duration of the study.
4.
Caregivers (and age-appropriate patients) must be willing and able to use an electronic diary 
(eDiary) device as required by the study.
Cohort 2:
1.
A male or female patient of any age, with a clinical diagnosis of PFIC, including episodic forms 
(i.e., BRIC), and with a body weight 5 kg at Visit S-1.
2.
Patient must have clinical genetic confirmation of PFIC.
3.
Patients with PFIC, excluding BRIC, must have elevated serum bile acid concentration, specifically 
measured to be
at least 7 days apart (Visits S-1 and 
S-2) prior to the Screening/Inclusion Visit (Visit 1).
4.
Patients with PFIC, excluding BRIC, must have history of significant pruritus and a caregiver- 
reported observed scratching or patient-reported itching (for patients >18 with no caregiver-reported 
observed scratching) 
the 2 weeks prior to the
Screening/Inclusion Visit (Visit 1).
5.
Patients with episodic forms of PFIC (i.e., BRIC) must have an emerging flare characterized by 
clinically significant pruritus and elevated serum bile acid levels/cholestasis as judged by the 
investigator.
6.
Patient and/or legal guardian must sign informed consent (and assent) as appropriate. Patients who 
turn 18 years of age (or legal age per country) during the study will be required to re-consent in 
order to remain in the study.
7.
Age-appropriate patients are expected to have a consistent caregiver for the duration of the study.
8.
Caregivers and age-
, if able) must be willing and able to use an 
eDiary device as required by the study.
Test Product, Dose and Mode of Administration:
A4250, 40 or 120 µg/kg/day orally administered.
Reference Therapy, Dose and Duration of Administration:
Not applicable.
Duration of Treatment:
72 weeks
Variables:

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 06, 21 December 2021 
7 
 
 
 
Name of Sponsor/Company: 
Albireo AB 
Name of Product: 
A4250 
Name of Active Ingredient: 
A4250 
Efficacy: 
Primary Efficacy Endpoints 
European Union (EU) and rest of world: Change from baseline in serum bile acids after 72 weeks of 
treatment. 
US: Proportion of positive pruritus assessments at the patient level over the 72-week treatment period using 
the Albireo observer-reported outcome (ObsRO) instrument. 
Secondary Efficacy Endpoints 
EU and rest of world: Proportion of positive pruritus assessments at the patient level over the 72-week 
treatment period using the Albireo ObsRO instrument. 
US: Change from baseline in serum bile acids after 72 weeks of treatment. 
All Regions: 
Change from baseline in serum bile acids at Weeks 4, 12, 22, 24, 36, 46, 48, 60, 70, 72, and 76 
Proportion of individual assessments meeting the definition of a positive pruritus assessment at the 
patient level using the Albireo ObsRO instrument from Weeks 0-4, Weeks 0-12, Weeks 0-22, 
Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, Weeks 0-60, and Weeks 0-70, respectively, or 
the proportion of positive pruritus assessments at each 4-week interval between Visit 1/Screening 
and Visit 5/Week 24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 
Proportion of individual AM assessments meeting the definition of a positive pruritus assessment at 
the patient level using the Albireo ObsRO instrument from Weeks 0-4, Weeks 0-12, Weeks 0-22, 
Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, Weeks 0-60, Weeks 0-70, and Weeks 0-72, 
respectively, or the proportion of positive pruritus assessments at each 4-week interval between 
Visit 1/Screening and Visit 5/Week 24, then by each visit between Visit 5/Week 24 to 
Visit 12/Week 76 
Proportion of individual PM assessments meeting the definition of a positive pruritus assessment at 
the patient level using the Albireo ObsRO instrument from Weeks 0-4, Weeks 0-12, Weeks 0-22, 
Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, Weeks 0-60, Weeks 0-70, and Weeks 0-72, 
respectively, or the proportion of positive pruritus assessments at each 4-week interval between 
Visit 1/Screening and Visit 5/Week 24, then by each visit between Visit 5/Week 24 to 
Visit 12/Week 76 
All-cause mortality, number of patients undergoing biliary diversion surgery or liver transplantation. 
These parameters will be evaluated separately and together at weeks 24, 48, and 72 
Change in growth from baseline to Weeks 24, 48, and 72 after initiation of A4250 treatment, defined 
as the linear growth deficit (height/length for age, weight for age, mid-arm circumference and body 
mass index [BMI]) compared to a standard growth curve (Z-score, standard deviation [SD] from P50) 
Change in aspartate aminotransferase (AST) to platelet ratio index (APRI) score and fibrosis-4 (Fib-4) 
score from baseline to Week 72 
Change in pediatric end-stage liver disease (PELD)/model for end-stage liver disease (MELD) score 
from baseline to Week 72 
Change in use of antipruritic medication at Weeks 24, 48, and 72 
Exploratory Efficacy Endpoints 
All Exploratory Endpoints will be evaluated at Weeks 24, 48, and 72 unless otherwise noted. Baseline is 
calculated prior to initiation of A4250 treatment. Exploratory endpoints include: 
Change in serum alanine aminotransferase (ALT), gamma-glutamyl transferase, and total bilirubin 
concentration from baseline to Week 72 

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Name of Sponsor/Company:
Albireo AB
Name of Product:
A4250
Name of Active Ingredient:
A4250
Proportion of individual assessments meeting the definition of a positive pruritus assessment at the 
patient level over the 72-week Treatment Period. A positive pruritus assessment includes an itch score
-point drop from baseline based on the Albireo patient-reported outcome (PRO) 
instrument;
years of age will complete the Albireo PRO instrument
Change from baseline over the 72-week treatment period in sleep parameters measured with the 
Albireo PRO and ObsRO instruments
Change from baseline in international normalized ratio, albumin, liver enzymes, leukocytes, and 
platelets
Change from baseline
-hydroxy-4-cholesten-3-
one [p-C4])
Assessment of Global Symptom Relief at weeks 4, 12, 24, 48 and 72 as measured by patient, caregiver, 
and clinician global impression of change (PGIC) items
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then 
by each visit between Visit 5/Week 24 to Visit 12/Week 76 in patient-reported and observer-reported 
night time itching and scratching severity scores, respectively
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then 
by each visit between Visit 5/Week 24 to Visit 12/Week 76 in patient-reported and observer-reported 
morning time itching and scratching severity scores, respectively
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then 
by each visit between Visit 5/Week 24 to Visit 12/Week 76 in pooled pruritus score including 
observer-reported scratching for patients <8 years of age and patient-reported itch severity for patients
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then 
by each visit between Visit 5/Week 24 to Visit 12/Week 76 in additional patient-reported and 
observer-reported sleep parameters (e.g., tiredness, number of awakenings)
Change from baseline in Pediatric Quality of Life Inventory (PedsQL) questionnaire 
Change from baseline in stage of liver fibrosis as assessed by Fibroscan® (where available)
Change from baseline in stage of liver fibrosis as assessed by post-treatment biopsy (when available)
Safety:
Safety criteria are as follows:
Occurrence of treatment-emergent AEs including severity and relatedness to study drug at all visits
The incidence of treatment-emergent serious adverse events (SAEs), based upon information from 
patient reports, including the description, causality, and severity of an SAE
Trends evaluated for the following assessments: physical examinations, concomitant medications, 
vital signs, laboratory test results (including clinical chemistry, hematology, urinalysis, alfa- 
fetoprotein, and vitamins A, E, and 25-hydroxy vitamin D), and abdominal ultrasound
Statistical Methods:
Descriptive statistics will mainly be used in this open-label extension study.
Baseline 1 will be defined as the last value prior to treatment start in study A4250-005 for Cohort 1 patients.
Baseline 2 will be defined as the last value prior to treatment start in Study A4250-008 for all patients. 
Baseline 2 will be used in all analyses unless otherwise specified.
The full analysis set (FAS) will consist of all patients who received at least 1 dose of study drug in Study 
A4250-008. The full analysis set will be the primary analysis set for all analyses unless otherwise specified. 
Evaluation of Primary Efficacy Variables:
The proportion of positive pruritus assessments at the patient level over the 72-week treatment period will be 
summarized.
-point drop
from baseline on the Albireo ObsRO instrument. At each assessment, the AM score will be compared to the
baseline AM average, and the PM score will be compared to the baseline PM average. Both AM and PM

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Name of Sponsor/Company: 
Albireo AB 
Name of Product: 
A4250 
Name of Active Ingredient: 
A4250 
pruritus assessments will be included in the analysis of this endpoint. Baseline will be defined as the average 
score from 14 days prior to treatment start in A4250-008 for AM and PM, respectively. 
The change from baseline over the treatment period in serum bile acids will be analyzed mainly by using 
descriptive statistics. Fasting serum bile acids baseline will be calculated as the average of the pre-dose value 
in Study A4250-008 (Visit 1) and the previous visit (Visit 8 in study A4250-005) for Cohort 1. Fasting 
serum bile acids baseline will be calculated as the average of Visit S-2 and the pre-dose Visit 1 values in 
Study A4250-008 for Cohort 2. The end value is the average of the values at Weeks 70 and 72 in study 
A4250-008. 
Descriptive statistics will be summarized for Cohort 1, Cohort 2 excluding BRIC, Cohort 2 BRIC, and 
combined Cohort 1 + Cohort 2 excluding BRIC. Within Cohort 1, the following subgroups will be 
presented: ‘A4250 40 µg/kg/day (-005) to 120 µg/kg/day (-008)’, ‘A4250 120 µg/kg/day (-005) to 120 
µg/kg/day (-008)’, ‘A4250 40 µg/kg/day (-005) and 120 µg/kg/day (-005) to 120 µg/kg/day (-008)’, and 
‘placebo (-005) to 120 µg/kg/day (-008)’. Within Cohort 2 excluding BRIC, 3 subgroups (‘40 µg/kg/day’, 
‘40 µg/kg/day to 120 µg/kg/day’, and ‘120 µg/kg/day’) will be presented. Cohort 1 Placebo to A4250 
120 µg/kg/day will also be combined with Cohort 2 excluding BRIC for presentations. Change over time 
will also be displayed using graphical presentations (e.g., a spaghetti plot which illustrates the change in both 
Study A4250-005 and Study A4250-008 by treatment group in Study A4250-005). 
Evaluation of Secondary and Exploratory Efficacy Variables: 
All secondary and exploratory variables will be analyzed descriptively for categorical and continuous data, as 
applicable. For continuous data, the change from baseline will be analyzed in addition to the actual visit values. 
For categorical data, shift tables or frequency and percentages of patients will be presented as appropriate. 
Change in growth (Z-score, SD from P50 standard growth curve) will be analyzed by using one-sample T-test 
or Wilcoxon signed-rank test as appropriate. Change in growth (height/length for age, weight for age, mid- 
arm circumference and BMI) will also be displayed using graphical presentations. 
A 95% confidence interval (CI) will be calculated for the proportion of patients with at least one event, i.e., 
bile diversion or liver transplantation or death. The upper boundary will be compared to the expected 
proportion of events, using the event probability estimated from the untreated reference population in an 
ongoing observational cohort study. 
Time to first event, i.e., time to surgical bile diversion or liver transplantation or death, will be explored by 
descriptive statistics and Kaplan-Meier curves, which also will be used to make a comparison to the untreated 
reference population. 
Evaluation of Safety Variables: 
Safety data will be analyzed using descriptive statistics and summaries overall of SAEs, AEs, vital signs, 
clinical laboratory tests (hematology, clinical chemistry and urinalysis) and concomitant medication. Analyses 
will be performed using the full analysis set. 
Sample Size Determination: 
There is no formal hypothesis testing in this open label-study. Sample size for Cohort 1 was determined in 
Study A4250-005. For Cohort 1, patients will be enrolled following completion or participation of at least 12 
weeks of Study A4250-005. The expected proportion of patients with at least one event, i.e., surgical bile 
diversion or liver transplantation or death, in untreated patients is expected to be high enough to be able to 
detect an improvement after A4250 treatment. If the expected proportion with at least one event is estimated 
to be 30% in the study population of Cohort 1, and then if the proportion of patients with at least one event 
during A4250 long-term treatment are shown to be only 10% in the study, the power is approximately 89% to 
96% (1-sided test, alpha=2.5%) for a CI with upper boundary <30% based on a sample size of n=48 to 60. The 
sample size of 60 patients for Cohort 2 was estimated based on the availability of target patient population to 
evaluate the therapeutic benefit for those patients. 
Date of the Protocol: 21 December 2021 

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3 
TABLE OF CONTENTS 
1 
ADMINISTRATIVE INFORMATION ................................................................... 4 
2 
STUDY SYNOPSIS ................................................................................................. 5 
3 
TABLE OF CONTENTS ....................................................................................... 10 
3.1 
List of Tables ............................................................................................ 14 
3.2 
List of Figures ........................................................................................... 14 
3.3 
List of Appendices and Supplements ........................................................ 14 
4 
LIST OF ABBREVIATIONS AND DEFINITION OF TERMS .......................... 15 
5 
INTRODUCTION .................................................................................................. 18 
5.1 
Investigational Medicinal Product ............................................................ 18 
5.2 
Background ............................................................................................... 18 
5.2.1 
Progressive Familial Intrahepatic Cholestasis ...................................... 18 
5.2.2 
Summary of Clinical and Nonclinical Studies ..................................... 20 
5.3 
Rationale .................................................................................................... 22 
5.3.1 
Risk/Benefit ........................................................................................... 23 
5.3.2 
Risk/Benefit  of  Receiving  COVID-19  Vaccine  during  Trial 
Participation ........................................................................................... 24 
6 
STUDY OBJECTIVES .......................................................................................... 26 
6.1 
Primary Objectives .................................................................................... 26 
6.2 
Secondary Objectives ................................................................................ 26 
7 
INVESTIGATIONAL PLAN ................................................................................ 27 
7.1 
Overall Study Design and Plan. ................................................................ 27 
7.1.1 
Description ............................................................................................. 27 
7.1.2 
Schedule of Assessments ....................................................................... 31 
7.1.3 
Study Procedures and Assessments....................................................... 40 
7.1.3.1 
Screening Period (Days -56 to 0) (For Cohort 2 only) ......... 40 
7.1.3.2 
Treatment Period ................................................................... 41 
7.1.3.3 
End of Treatment/Early Termination/Start of Optional 
Extension Period .................................................................... 46 
7.1.3.4 
Follow-up Visit ..................................................................... 46 
7.1.3.5 
Optional Extension Period .................................................... 47 
7.1.3.6 
Optional Extension Period End of Treatment ....................... 47 
7.2 
Study Population ....................................................................................... 48 
7.2.1 
Inclusion Criteria ................................................................................... 48 
7.2.2 
Exclusion Criteria .................................................................................. 49 
7.2.3 
Withdrawal of Patients .......................................................................... 51 

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7.2.4 
Study Termination by Sponsor ............................................................. 52 
8 
TREATMENT OF PATIENTS .............................................................................. 53 
8.1 
Identity of Study Drug .............................................................................. 53 
8.2 
Administration of Study Drug .................................................................. 53 
8.3 
Study Drug Packaging and Labelling ....................................................... 56 
8.3.1 
Packaging and Labelling ....................................................................... 56 
8.3.2 
Storage ................................................................................................... 56 
8.3.3 
Blinding and Randomization of Study Drug ........................................ 56 
8.4 
Procedure for Breaking the Randomization Code .................................... 56 
8.5 
Patient Compliance ................................................................................... 56 
8.6 
Patient Identification ................................................................................. 57 
8.7 
Study Drug Accountability........................................................................ 57 
8.8 
Concomitant Therapy and Prohibited Medications .................................. 57 
9 
ASSESSMENT OF EFFICACY ............................................................................ 58 
9.1 
Efficacy Endpoints .................................................................................... 58 
9.1.1 
Primary Efficacy Endpoints .................................................................. 58 
9.1.2 
Secondary Efficacy Endpoints .............................................................. 58 
9.1.3 
Exploratory Efficacy Endpoints ............................................................ 59 
9.2 
Efficacy Assessments ................................................................................ 60 
9.2.1 
Serum Bile Acids .................................................................................. 60 
9.2.2 
Itching and Sleep Score ......................................................................... 60 
9.2.3 
Growth ................................................................................................... 61 
9.2.4 
Biomarker Samples ............................................................................... 61 
9.2.5 
Change of Antipruritic Medication ....................................................... 61 
9.2.6 
Quality of Life Questionnaire (PedsQL) ............................................... 61 
9.2.7 
PELD/MELD Score .............................................................................. 61 
9.2.8 
Fibroscan® ............................................................................................................................................. 62 
9.2.9 
Markers of Fibrosis ............................................................................... 62 
9.2.10 
Liver Biopsy .......................................................................................... 62 
9.2.11 
Global Impression of Change and Global Impression of Symptom 
Measures ................................................................................................ 62 
10 
ASSESSMENT OF SAFETY ................................................................................ 63 
10.1 
Adverse Events ......................................................................................... 63 
10.1.1 
Definitions and Investigator Assessments ............................................ 63 
10.1.1.1 Clinical Significance .............................................................. 63 
10.1.1.2 Serious Adverse Events ......................................................... 63 

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10.1.1.3 Severity Assessment .............................................................. 64 
10.1.1.4 Causality Assessment ............................................................ 64 
10.1.2 
Recording of Adverse Events ............................................................... 65 
10.1.3 
Recording and Reporting of Serious Adverse Events .......................... 66 
10.1.4 
Reporting of Suspected Unexpected Serious Adverse Reactions ........ 67 
10.2 
Laboratory Values/Vital Signs/Physical Examinations and Other Safety 
Assessments ............................................................................................... 68 
10.2.1 
Laboratory Assessments ........................................................................ 68 
10.2.2 
Individual Patient Safety Monitoring .................................................... 69 
10.2.2.1 Liver Monitoring.................................................................... 69 
10.2.2.2 Close Observation .................................................................. 70 
10.2.2.3 De-challenge/Re-challenge for Liver and Clinical Hepatitis 
Monitoring ............................................................................. 71 
10.2.2.4 Diarrhea ................................................................................. 71 
10.2.2.5 Fat-soluble Vitamin Deficiency ............................................ 72 
10.2.2.6 Treatment-emergent Iron Deficiency Anemia ...................... 72 
10.2.2.7 Re-challenge after Discontinuation/Interruption of Study 
Drug ....................................................................................... 72 
10.2.2.8 Monitoring after Permanent Discontinuation of Study Drug 
Due to Safety ......................................................................... 73 
10.2.3 
Demographics/Medical and Surgical History (For Cohort 2 only) ...... 73 
10.2.4 
Clinical Genetic Testing (For Cohort 2 only) ....................................... 73 
10.2.5 
Physical Examination ............................................................................ 73 
10.2.6 
Vital Signs ............................................................................................. 74 
10.2.7 
Abdominal ultrasound ........................................................................... 74 
10.2.8 
Overdose ................................................................................................ 74 
10.2.9 
Pregnancy .............................................................................................. 74 
11 
STATISTICAL EVALUATION ............................................................................ 76 
11.1 
Sample Size and Power............................................................................. 76 
11.2 
Statistical Methods .................................................................................... 76 
11.2.1 
Statistical Analysis Sets ........................................................................ 76 
11.2.2 
Methods of Statistical Analyses ............................................................ 76 
11.2.2.1 General Principles .................................................................. 76 
11.2.2.2 Missing Data .......................................................................... 77 
11.2.2.3 Demographic and Baseline Characteristics ........................... 77 
11.2.2.4 Subject Disposition ................................................................ 77 

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11.2.2.5 Evaluation of Primary Efficacy Variables ............................ 78 
11.2.2.6 Evaluation of Secondary and Exploratory Efficacy Variables 
. ............................................................................................ 78 
11.2.2.7 Evaluation of Safety Variables .............................................. 79 
11.2.2.8 Compliance and Exposure ..................................................... 79 
11.2.3 
Interim Analysis .................................................................................... 80 
11.2.4 
Data Safety Monitoring Board .............................................................. 80 
12 
DIRECT ACCESS TO SOURCE DATA/NOTES ................................................. 81 
13 
QUALITY CONTROL AND QUALITY ASSURANCE ...................................... 82 
13.1 
Conduct of the Study ................................................................................. 82 
13.2 
Study Monitoring ....................................................................................... 82 
14 
ETHICS ................................................................................................................... 84 
14.1 
Independent Ethics Committee/Institutional Review Board ..................... 84 
14.2 
Written Informed Consents and Assents ................................................... 84 
15 
DATA HANDLING AND RECORD KEEPING .................................................. 86 
15.1 
Case Report Forms/Source Data Handling. ............................................... 86 
15.2 
Retention of Essential Documents ............................................................. 86 
16 
FINANCING AND INSURANCE .......................................................................... 87 
17 
PUBLICATION POLICY ....................................................................................... 88 
18 
REFERENCE LIST ................................................................................................. 89 
19 
APPENDICES ......................................................................................................... 91 

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3.1 
List of Tables 
Table 1 
Schedule of Assessments (Screening Period through Follow-up Period).. 32 
Table 2 
Schedule of Assessments (Optional Extension Period) ............................... 38 
Table 3 
Dosing and Capsule Strength ........................................................................ 55 
Table 4 
Routine Laboratory Parameters .................................................................... 69 
 
 
3.2 
List of Figures 
Figure 1 
Study Design ................................................................................................. 30 
Figure 2 
Study Design for Cohort 2 as of Protocol Amendment 6 ............................ 30 
 
 
3.3 
List of Appendices and Supplements 
Appendix 1 
Concomitant Medication Guidelines ............................................................ 91 
Appendix 2 
Diary Questions including Albireo Patient-Reported 
Outcomes/Observer-Reported Outcome Instrument .................................... 93 
Appendix 3 
Patient Global Impression of Change (PGIC) and Patient Global Impression 
of Symptoms (PGIS) ..................................................................................... 96 
Appendix 4 
Pediatric Quality of Life Inventory (PedQL) Questionnaire ...................... 101 
Appendix 5 
Guideline for Fat-Soluble Vitamin Supplementation ................................. 122 
Appendix 6 
Contraceptive Requirements ....................................................................... 125 
Appendix 7 
Blood Volumes ........................................................................................... 128 

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4 
LIST OF ABBREVIATIONS AND DEFINITION OF TERMS 
A4250 
odevixibat (non-proprietary name); Bylvay (brand name) 
ADME 
absorption, distribution, metabolism, and excretion 
AE(s) 
adverse event(s) 
AFP 
alfa-fetoprotein 
ALT 
alanine aminotransferase 
APRI 
AST to platelet ratio index 
ASBT 
apical sodium-dependent bile transporter (also known as IBAT) 
AST 
aspartate aminotransferase 
ATC 
Anatomical Therapeutic Chemical 
BMI 
body mass index 
BRIC 
benign recurrent intrahepatic cholestasis 
BSEP 
bile salt export pump 
CI 
confidence interval 
COVID-19 
coronavirus disease 2019 
CPK 
creatine phosphokinase 
CRA 
clinical research associate 
CYP 
cytochrome P450 
DDI 
drug-drug interaction 
DILI 
drug-induced liver injury 
DSMB 
Data and Safety Monitoring Board 
eCRF 
electronic case report form 
eDiary 
electronic diary 
EMA 
European Medicines Agency 
EOT 
End of Treatment 
EU 
European Union 
EudraCT 
 European Union drug regulatory agency clinical trial 
FAS 
full analysis set 
FDA 
(United States) Food and Drug Administration 
Fib-4 
fibrosis-4 
FIC1 
familial intrahepatic cholestasis-1 
FXR 
farnesoid X receptor 
GCP 
Good Clinical Practice 
GGT 
gamma-glutamyl transferase 
GI 
gastrointestinal 
IB 
Investigator’s Brochure 

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IBAT
ileal bile acid transporter (also known as ASBT)
ICF
informed consent form
ICH
International Council for Harmonisation
IEC
Independent Ethics Committee
INR
international normalized ratio
IRB
Institutional Review Board
iRIS
ICON Results Integration Services
IWRS
Interactive Web Response System
LDH
lactate dehydrogenase
LFT
liver function test
LPLV
last patient last visit
MDR3
multidrug-resistance protein 3 
MedDRA
Medical Dictionary for Regulatory Activities
MELD
model for end-stage liver disease
NAPPED
Natural Course and Prognosis of PFIC and Effect of Biliary 
Diversion
ObsRO
observer-reported outcome
PBC
primary biliary cholangitis
p-C4
 
-hydroxy-4-cholesten-3-one 
PCS
potentially clinically significant
PEDFIC 1 
Study A4250-005
PEDFIC 2 
Study A4250-008
PedsQL
Pediatric Quality of Life Inventory
PELD
pediatric end-stage liver disease
PFIC
progressive familial intrahepatic cholestasis
PGIC
patient global impression of change
PGIS
patient global impression of symptoms
P-gp
P-glycoprotein
PK
pharmacokinetic
PRO
patient-reported outcome
PT
prothrombin time
PVM
pharmacovigilance manager
QD
once daily
QoL
quality of life
SAE(s)
serious adverse event(s)
SAP
statistical analysis plan

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s-FGF19 
serum fibroblast growth factor 19 
SD 
standard deviation 
SOC 
system organ class 
SUSAR 
suspected unexpected serious adverse reaction 
TEAE(s) 
treatment-emergent adverse event(s) 
TJP2 
tight junction protein 2 
ULN 
upper limit of normal 
US 
United States 
WHO 
World Health Organization 

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5
INTRODUCTION
5.1
Investigational Medicinal Product
A4250 is a small molecule and a potent selective inhibitor of the ileal bile acid transporter 
(IBAT), also known as the apical sodium-dependent bile acid transporter (ASBT). IBAT is an 
integral brush border membrane glycoprotein that co-transports sodium and bile acids and 
appears to be a critical component in the regulation of the bile acid pool size in animals and 
man. This transporter, expressed in the distal ileum, is a key element in the enterohepatic 
circulation of bile acids since it facilitates the high-affinity, high-capacity reabsorption of bile 
acids.
Indeed, 95% of secreted bile acids are reabsorbed via IBAT [Hofmann 2009;
Miethke 2016]. A4250 is orally administered and acts locally in the gut where it binds 
reversibly to IBAT to decrease the reuptake of bile acids. A4250 has minimal systemic 
exposure at the predicted therapeutic dose ranges.
5.2
Background
5.2.1
Progressive Familial Intrahepatic Cholestasis
PFIC is a rare autosomal recessive cholestatic liver disease estimated to affect between one in 
every 50,000 to 100,000 children born worldwide. PFIC represents 10% to 15% of causes of 
cholestasis in children and 10% to 15% of liver transplantation indications in children. All 
types of PFIC exist worldwide and both sexes appear to be equally affected. 
The common underlying pathogenesis of PFIC is disruption of bile formation and bile transport 
through the liver [Jacquemin 2000]. The classification of PFIC has evolved over the years. 
The most commonly used subclassification is PFIC Types 1 to 6 which is based on the 
associated affected gene and described in more detail below.
PFIC, Type 1: also referred to as “Byler disease” or “familial intrahepatic cholestasis 1 
(FIC1) protein deficiency.” FIC1 protein is located on the canalicular membrane of 
hepatocytes and facilitates movement of aminophospholipids from the outer to inner leaflet 
of the plasma membrane of the hepatocyte. The ATP8B1 gene encodes FIC1 protein. 
Biallelic pathologic variants in the ATP8B1 gene are associated with FIC1 dysfunction and 
classified clinically as PFIC Type 1 disease.
PFIC, Type 2: also referred to as “Byler syndrome” or “bile salt export pump (BSEP) 
deficiency.” BSEP is a transporter protein that is expressed at the canalicular membrane 
of hepatocytes and is the primary exporter of bile acids. The ABCB11 gene encodes the 
BSEP protein. Biallelic pathologic variations in the ABCB11 gene is associated with BSEP 
dysfunction and is classified clinically as PFIC Type 2 disease.
PFIC, Type 3: is caused by a deficiency of the multidrug-resistance protein 3 (MDR3) due 
to mutations in the ABCB4 gene. MDR3 is a phospholipid translocase critical for 
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PFIC, Type 4 (tight junction protein 2 [TJP2] deficiency): is caused by biallelic mutations
in the TJP2 gene which encodes the tight junction protein 2 (TJP2) which is also called
zona occludens-2 [Bull 2018]. TJP2 is a cytoplasmic protein of cell-cell junctional 
complexes. While not part of the tight junction itself, tight junction proteins are closely 
associated with proteins that do form tight junctions, such as the claudins. 
PFIC, Type 5 (farnesoid X receptor [FXR] deficiency): Loss of function mutations in the 
NR1H4 gene encoding the farnesoid X receptor (FXR) result in PFIC5 [Sticova 2018]. FXR 
is a nuclear receptor activated by bile acids and is directly involved in the expression of
both BSEP and MDR3, proteins affected in PFIC2 and PFIC3, respectively [Gomez-Ospina
2016].
PFIC, Type 6 (MYO5B deficiency): PFIC6 results from defects in the Myo5B gene that 
codes for the actin-associated molecular motor known as MYO5B, which is essential for
the polarisation of hepatocytes as well as localising BSEP to the canalicular membrane 
[Vitale 2019]. 
Severe pruritus is common in children diagnosed with PFIC. Itching (and subsequent 
scratching) is a significant morbidity for these patients and their families [Suchy 2007]. A 
more severe degree of pruritus is experienced compared to patients with other forms of liver 
disease and to other pruritic conditions such as atopic dermatitis [Murray 2011]. In patients 
with PFIC, liver biopsy reveals canalicular cholestasis and, later, the appearance of portal 
fibrosis. Serum biochemistry indicates cholestasis with hyperbilirubinemia, elevated alanine 
aminotransferase (ALT) and aspartate aminotransferase (AST). The concentrations of bile
acids in serum are very high, while serum gamma-glutamyl transferase (GGT) activity (the 
exception being MDR3 variants) and cholesterol [Hori 2010] are normal. Symptoms of portal 
hypertension and liver failure will develop during the course of the disease [Davit-Spraul 2009;
Alissa 2008]. Symptoms develop early; median age at onset of symptoms is 2 months, and
78% of PFIC patients present with jaundice [Pawlikowska 2010]. The life-threatening and 
debilitating nature of PFIC is reflected by the fact that survival in those not resorting to surgery 
is 50% at 10 years of age and almost zero at 20 years of age. Approximately half of PFIC 
patients undergo liver transplantation [Davit-Spraul 2009] and treatment resistant pruritus is 
the leading indication for the surgical procedure partial external biliary diversion, mostly in 
PFIC Type 1 and 2 patients. 
PFIC is life-threatening and debilitating. Other than odevixibat, which is approved for the 
treatment of PFIC by the European Medicines Agency (EMA) and for the treatment of pruritus 
in patients with PFIC by the United States Food and Drug Administration (US FDA), the 
therapeutic choices are restricted to non-specific therapy of the symptoms and signs of the 
disease such as nutritional support, preventing vitamin deficiencies, and treatment of 
extrahepatic features. Medical treatment options include off-label use of ursodeoxycholic acid, 
rifampin, antihistamines, and naltrexone. A minority of patients respond nominally and 
transiently to these interventions. Biliary diversion is used to decrease systemic bile acids

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through interruption of the enterohepatic circulation and so avoid transplantation. Liver 
transplantation is typically only viewed as an option when patients have failed medical 
treatment and/or biliary diversion and have liver failure or persistent uncontrolled pruritus. 
Previously, the term benign recurrent intrahepatic cholestasis (BRIC) was used to identify a 
group of patients with episodic cholestasis including severe pruritus and jaundice. Genetic 
analysis of patients with episodic cholestasis have identified mutations in the ATP8B1 and 
ABCB11 genes (the same mutations as PFIC1 and PFIC2). It is now generally recognised that, 
within each subtype, PFIC and BRIC represent 2 extremes of a continuous spectrum of 
phenotypes of the one disease [Bull 2018; Stapelbroek 2010; Sticova 2018]. 
Genetic diagnosis of BRIC Type 1 or BRIC Type 2 is based on evidence of mutations in both 
alleles of the corresponding genes. While the age of first manifestation can vary widely, BRIC 
usually manifests before the second decade of life. There is great variability in terms of 
frequency (months to years), duration (several days to several months), and intensity of 
cholestatic episodes. Clinical symptoms may include pruritus, jaundice, fatigue, anorexia, and 
steatorrhea [Strubbe 2012; Sticova 2018]. 
During cholestatic episodes, serum bile acids and bilirubin are typically increased, while GGT 
and serum cholesterol levels are normal [Sticova 2018]. Aminotransferases may be slightly 
elevated. Liver biopsies have shown hepatocanalicular cholestasis without fibrosis during 
cholestatic episodes and normal histology during the asymptomatic period. 
Therapeutic options for BRIC have not been very effective, including statins, corticosteroids, 
cholestyramine, or ursodeoxycholic acid [Sticova 2018]. While improvement in pruritus and 
decreased duration of symptomatic episodes have been reported with rifampicin, severe 
hepatotoxicity after long-term administration has been reported in patients with cholestatic 
disorders. 
5.2.2 
Summary of Clinical and Nonclinical Studies 
This is a summary of nonclinical and clinical studies. More detail is provided in the 
Investigator Brochure ([IB] see A4250 IB). 
A4250 is a potent selective IBAT inhibitor with no safety signals seen in the safety 
pharmacological studies. In addition, no safety signals were seen in repeat-dose oral toxicity 
studies in rats with up to 26 weeks of daily dosing and in dogs with up to 39 weeks of daily 
dosing. A4250 showed no carcinogenic potential in 2-year carcinogenicity studies conducted 
in mice and rats. No safety signals were identified when A4250 was administered daily to 
juvenile rats from age 14 days to 63 days. Based on findings from animal reproduction studies, 
A4250 may cause cardiac malformations when a fetus is exposed during pregnancy. In 
pregnant rabbits treated orally with A4250 during organogenesis, an increased incidence of 
malformations in fetal heart, great blood vessels, and other vascular sites occurred at all doses; 
maternal systemic exposure at the lowest dose was 2.1 times the maximum recommended dose. 
No such malformations were observed when odevixibat was administered to pregnant rats. 

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A4250 had no effect on the reproductive performance, fertility, embryo-foetal development, or 
prenatal/postnatal development studies in rats.
A4250 is minimally absorbed with very low systemic exposure in both humans and other 
species. In blood, protein binding is high (>99.7%). Systemically absorbed A4250 is slowly 
metabolized in humans and in preclinical studies by hydroxylation only, a metabolite that
retains IBAT activity.  A4250 did not show any significant inhibition of cytochrome 
P450 (CYP)
enzymes
in
the
rat.
A4250
inhibited
human
CYP3A4
and
CYP2D6 
(IC50: 16 µmol/L for both enzymes), and CYP2C9 (IC50: 1.2 µmol/L).
To date, A4250 has been studied in 6 completed Albireo-sponsored clinical studies: a study in 
healthy volunteers evaluating single and multiple administration of A4250; a single-dose 
absorption, distribution, metabolism, and excretion (ADME) study; a single-dose food 
interaction study in healthy subjects; a drug-drug interaction (DDI) study in healthy subjects; 
a Phase 2 study in children with cholestatic pruritus; and a Phase 3 study in children with PFIC. 
In addition, an investigator-sponsored study has been conducted in patients with primary biliary 
cholangitis (PBC). In total, 258 subjects/patients have been exposed to A4250 in completed
and ongoing studies.
In healthy volunteers (study A4250-001), dosing with A4250 at single doses of 0.1-10.0 mg
and multiple doses from 1-3 mg daily for up to 7 days induced anticipated changes in bile acid 
synthesis biomarkers (i.e., decreased serum fibroblast growth factor 19 [s-FGF19] and
increased 
hydroxy 4-cholesten-3-one [p-C4]). In addition, total plasma bile acids 
decreased and total fecal bile acids increased compared to placebo treatment.
The clinical development program has generated data demonstrating minimal systemic total 
exposure in the low nanomolar range with very high protein binding and no detectable levels 
of metabolites. An ADME study (A4250-007) demonstrated that A4250 is excreted unchanged 
primarily in the feces. A population pharmacokinetic (PK) analysis confirmed that A4250 
presented very low systemic exposure in pediatric patients with PFIC with rapid elimination.
No accumulation of A4250 is expected following repeated administration of therapeutic doses 
(40 and 120 µg/kg/day). No dose adjustment is required in subpopulations.
In a food interaction study (A4250-004) following administration of a single oral dose of
9.6 mg A4250, plasma concentrations and systemic exposure to A4250 were low, regardless 
of feeding status, indicating minimal absorption through the gastrointestinal (GI) tract. In a
DDI study (A4250-013), no clinically relevant drug-drug interactions with A4250 and a 
CYP3A4 substrate or a P-glycoprotein (P-gp) inhibitor were identified, although A4250 was a 
P-gp substrate. 
In a study with 4-week, once-daily oral treatment with A4250 in children with cholestatic liver 
disease and pruritus, A4250 reduced mean levels of serum bile acids in all treatment groups 
(5 dose groups ranging from 10-200 µg/kg/day [0.01-0.20 mg/kg/day]) (Study A4250-003). 
Patient-reported diaries documented improvement of the visual analogue scale (VAS)-itch

A4250 – IND 130591 
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score (Scale 0-10) in 17 of 24 patients during treatment, with the greatest improvement at a 
dose of 100 µg/kg/day. 
In a Phase 3 randomized double-blind study in children with PFIC, treatment with A4250 at 
doses of 40 and 120 µg/kg/day led to statistically significant reductions in serum bile acid levels 
and pruritus symptoms over 24 weeks compared with placebo (study A4250-005; PEDFIC 1). 
These improvements occurred rapidly and were sustained during continued treatment. Results 
for secondary and exploratory endpoints were generally consistent with the reductions in serum 
bile acids and pruritus showing improvements in sleep, hepatic biochemical parameters and 
hepatic health, and quality of life (QoL) measures. 
A4250 has been generally well tolerated in all completed studies. Adverse events (AEs) 
reported have primarily been of mild to moderate intensity. In total, 6 serious adverse events 
(SAEs) have been reported; none judged by the investigator to be causally related to the study 
drug. No deaths related to the drug have been reported. Abdominal pain and diarrhea have 
been the most prominent AEs in adults, while diarrhea, pyrexia, and upper respiratory tract 
infection have been the most commonly reported AEs in children. The most commonly 
reported study drug-related AEs in children were increases in alanine aminotransferase (ALT), 
aspartate aminotransferase (AST), and blood bilirubin. 
 
 
5.3 
Rationale 
The investigational product A4250 (non-proprietary name odevixibat; brand name Bylvay) has 
been approved for the treatment of PFIC by the EMA and for the treatment of pruritus in 
patients with PFIC by the US FDA. A4250 is also currently being developed for other orphan 
cholestatic liver diseases. 
In PFIC patients with severe pruritus, biliary diversion surgery is used to decrease systemic 
bile acids through interruption of the enterohepatic circulation and thereby reduce pruritus 
[Whitington 1988]. Liver transplantation is typically used as an option when patients have 
failed medical treatment and/or biliary diversion and have liver failure or persistent 
uncontrolled pruritus. 
By inhibiting IBAT with high selectivity and potency, A4250 has the potential to relieve 
cholestasis and improve liver function without surgical intervention in patients with PFIC. 
Since A4250 is minimally absorbed and achieves a substantial reduction of serum bile acids, it 
has the potential to be a safer and less invasive alternative to surgical biliary drainage. The 
rationale for using A4250 is to decrease serum bile acid levels, and to reduce the major 
morbidity of pruritus, improving the health and wellbeing of patients affected with PFIC. 
Ultimately, this noninvasive therapeutic approach has the potential to not only improve QoL, 
but also reduce the need for biliary diversion and subsequent liver failure and liver 
transplantation. 

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The doses selected for the A4250-005 Phase 3 study, 40 and 120 µg/kg/day, were based on the 
efficacy and safety data generated from patients with PFIC (n=10 + 3 re-entered) and 
supporting data from all patients (n=20 + 4 re-entered) in the five dose groups dosed in the 
A4250-003 Phase 2 study. Improvements of serum bile acids and pruritus were observed with 
doses from 30 to 100 µg/kg/day with a dose-related trend. The best dose response in all patients 
was at the 60 µg/kg/day for serum bile acids and 100 µg/kg/day for pruritus. The best dose 
response in the PFIC subgroup was at 30 µg/kg/day for both serum bile acids and pruritus. 
Patients with PFIC responded well to the doses given from 30 to 200 µg/kg/day; however, a 
clear dose relationship could not be established in order to select a single dose for the A4250- 
005 study. As efficacy was observed at both low and high doses, 40 and 120 µg/kg/day were 
considered to be the most optimal for the A4250-005 study. Both low and high doses, 
40 µg/kg/day 2 and 120 µg/kg/day, will be used in this study.  Patients not tolerating the 
120 µg/kg/day dose may down-titrate to the lower dose after a minimum of 1 week on the high 
dose. The patient should return to the higher dose as soon as deemed appropriate by the 
investigator. More than one upward dose titration (from 40 µg/kg/day directly to 120 
µg/kg/day) for the same event is not recommended. Any dose titration should be done in 
consultation with the sponsor Medical Monitor or designee. 
Rationale for patient selection: 
Cohort 1: Patients in Cohort 1 are children with PFIC Types 1 and 2 who have completed study 
A4250-005 (PEDFIC 1) and will be enrolled to collect data on the efficacy (impact on pruritus 
and clinical laboratory parameters) and safety of long-term administration of A4250. 
Cohort 2: Cohort 2 will enroll patients with PFIC who (1) were not eligible to enroll in 
A4250-005 (PEDFIC 1) or (2) are eligible for enrolment in A4250-005 after recruitment of 
study A4250-005 has been completed. As these patients will have cholestatic liver disease 
with elevated serum bile acids and pruritus, reduction of serum bile acids with A4250 treatment 
is believed to provide a therapeutic benefit for these patients. These patients will be enrolled 
to collect data on the efficacy (impact on pruritus and clinical laboratory parameters) and safety 
of long-term administration of A4250. 
This study will be conducted in compliance with the protocol and with the International 
Council for Harmonisation (ICH) guidelines on Good Clinical Practice (GCP). 
5.3.1 
Risk/Benefit 
Following review of the available safety and efficacy data, A4250 has been approved by the 
EMA and the US FDA for use in patients with PFIC. A4250 has been evaluated in 6 Albireo- 
sponsored clinical studies: a double-blind placebo-controlled study in healthy volunteers, a 
single-dose ADME study, a single-dose food interaction study, a DDI study, a Phase 2 study 
 
2 As of Protocol Amendment 6, patients entering Cohort 2 will start treatment at 40 µg/kg/day with the 
possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus based on 
investigator judgment. 

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in children with cholestatic pruritus, and a Phase 3 study in children with PFIC. In addition, 
an investigator sponsored study has been conducted in patients with PBC. 
A total of 258 subjects/patients have been exposed to A4250. Healthy subjects have been 
exposed to up to 10 mg as a single dose and up to 3 mg daily as part of a multiple-dose 
evaluation. Children with cholestatic liver disease have been treated with up to 200 µg/kg/day 
for 4 weeks. In the Phase 3 study in children with PFIC, children have been treated with A4250 
for 24 weeks at a dose of 40 
Two SAEs were reported in the 
Phase 2 study and 4 SAEs were reported in 3 patients receiving A4250 in the Phase 3 study; 
all were judged by the investigator to be not related to the study drug.
Patients with cholestatic liver diseases suffer from excess bile acids in the liver resulting in 
tissue damage. A commonly used treatment in these patients is bile diversion surgery, whereby 
approximately 50% to 100% of the enterohepatic circulation of bile acids is interrupted. 
Inhibition of IBAT with A4250, thereby interrupting the enterohepatic circulation of bile acids, 
is therefore a potential medical alternative to surgery which could be of benefit to these patients 
if shown to be effective and safe. Data from the Phase 2 and 3 studies showed efficacy of 
A4250 in reducing serum bile acid concentrations and pruritus in such patients. 
Based on the mode of action of A4250, an IBAT inhibitor, loose stools or diarrhea, and 
abdominal pain are expected AEs. Non-serious diarrhea and abdominal pain were reported in 
healthy volunteers and in the investigator-initiated PBC study and in one patient following 
single dose, but none following multiple dosing in the Phase 2 study in pediatric patients with 
pruritic cholestatic liver disease. Non-serious diarrhea, vomiting, and abdominal pain were 
observed in the Phase 3 study in pediatric patients with PFIC. 
A4250 taken once daily (QD) at doses up to 200 µg/kg/day, as tested in the Phase 2 study 
A4250-003, and up to 120 µg/kg/day as evaluated in the Phase 3 study A4250-005, was overall 
well tolerated. Gastrointestinal (GI) treatment-emergent adverse events (TEAEs) including 
abdominal pain, abdominal discomfort and diarrhea or loose stool, were associated in time with 
the onset of the treatment effect of A4250. In general, these AEs were mild to moderate in 
nature and self-limiting, did not require treatment intervention and were not linked to the degree 
of reduction of serum bile acid or a rapid reduction in serum bile acid levels. 
5.3.2
Risk/Benefit of Receiving COVID-19 Vaccine during Trial Participation
Nonclinical: The risk of immunotoxicity has been evaluated based on results from standard 
toxicity studies. No obvious signs in related organs have been detected in response to A4250 
treatment (e.g., changes in thymus, spleen, lymph nodes, or bone marrow). Altered hematology 
and incidence of infection have not been detected. Neither IBAT specifically nor bile acids in 
general are expected to perturb immunological responses. No signs of immunological reactions 
have been seen in clinical trials thus far. Based on the outcome from the standard toxicity 
studies and the general profile and mechanism of action of A4250, the risk of immunotoxicity 
has been considered low and dedicated immunotoxicity studies have not been performed. 

A4250 – IND 130591 
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Clinical: Based on an integrated safety analysis of data from the completed A4250-005 study 
and the ongoing open-label extension study A4250-008 in patients with PFIC treated for 48 
weeks or longer with A4250, no safety signal or trends relative to immunological reactions 
have been reported. This is consistent with the mechanism of action of A4250 and the non- 
clinical data. No trends or safety signals were observed as it relates to hematology including 
white blood cell count, differential counts and C-reactive protein. No events of allergic 
reactions to A4250 or its excipients have been reported. 
The overall incidence of infections was 49% (41 of 84 patients) with upper respiratory tract 
infection being the most common type of infection reported in 24% of patients. Other 
commonly reported infections were 
nasopharyngitis, 
otitis media, influenza, 
and 
gastroenteritis, reported in 11%, 7%, 6%, and 6%, respectively, of patients in the PFIC Phase 
3 studies. 
The risk of an undesirable outcome after receiving the COVID-19 vaccine while treated with 
A4250 has not been studied and is unknown. 

A4250 – IND 130591 
EudraCT 2017-002325-38
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6
STUDY OBJECTIVES
6.1
Primary Objectives
Primary Objective (Cohort 1)
To demonstrate a sustained effect of A4250 on serum bile acids and pruritus in children with 
PFIC Types 1 and 2. 
Primary Objective (Cohort 2)
To evaluate the effect of A4250 on serum bile acids and pruritus in patients with PFIC who 
either (1) do not meet eligibility criteria for Study A4250-005 (PEDFIC 1) or (2) who do 
meet the eligibility criteria for Study A4250-005 after recruitment of Study A4250-005 has 
been completed. 
6.2
Secondary Objectives
Secondary Objectives (Cohorts 1 and 2)
The secondary objectives of this study are:
To evaluate the long-term safety and tolerability of repeated daily doses of A4250 
 
To evaluate the effect of A4250 on growth 
To evaluate the effect of A4250 on biliary diversion and/or liver transplantation
To evaluate the effect of A4250 on biochemical markers of cholestasis and liver disease

A4250 – IND 130591 
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7
INVESTIGATIONAL PLAN
7.1
Overall Study Design and Plan
7.1.1
Description
This is a Phase 3, multi-center, open-label extension study to investigate the long-term efficacy 
and safety of a 120 µg/kg daily dose of A4250 in patients with PFIC, including episodic forms 
also referred to as BRIC. Cohort 1 will consist of children with PFIC Types 1 and 2 who have 
participated in Study A4250-005. Cohort 2 will consist of approximately 60 patients with any 
type of PFIC who have elevated serum bile acids and cholestatic pruritus and who either (1) do 
not meet eligibility criteria for Study A4250-005 (PEDFIC 1) or (2) are eligible for enrolment
in A4250-005 after recruitment of study A4250-005 has been completed. Up to 40 patients
post biliary diversion surgery are allowed to participate in Cohort 2. 
The study includes a 72-week Treatment Period and a 4-week Follow-up Period. Patients who 
wish to continue receiving A4250 after 72 weeks will have the option to remain on treatment 
in an extension period with visits every 16 weeks until the drug is commercially available, 
provided continued use is supported by the risk-benefit profile and the subject has not been 
previously withdrawn or discontinued from the study. In that case the 4-week Follow-up 
Period will not occur.
The study data will be reviewed periodically (approximately on a quarterly basis) by a Data 
Safety and Monitoring Board (DSMB) until the last patient reaches 72 weeks. 
Eligible patients will be enrolled into this open-label extension study and treated with a daily 
dose of 40 µg/kg/day3 or 120 µg/kg/day of A4250 for 72 weeks, or 40 µg/kg/day for the first 
12 weeks followed by 120 µg/kg/day for the remaining 60 weeks3. Patients not tolerating the 
120 µg/kg/day dose after a minimum of 1 week for reasons other than new liver findings and 
severe diarrhea, as described in Section 10.2.2, will have the option to down-titrate to a lower 
dose (40 µg/kg/day). The patient should return to the higher dose as soon as deemed 
appropriate by the investigator. More than one upward dose titration (from 40 µg/kg/day
directly to 120 µg/kg/day) for the same event is not recommended. Any dose titration should 
be done in consultation with the sponsor Medical Monitor or designee.
Patients participating in the optional extension period will continue on a daily dose of 
40 µg/kg/day or 120 µg/kg/day of A4250 with the option to down-titrate to a lower dose 
(40 µg/kg/day). 
Patients in Cohort 2 will go through a screening period consisting of:
Visit S-1: Screening Visit 1 (Days -56 to -35). 
3 As of Protocol Amendment 6, patients entering Cohort 2 will start treatment at 40 µg/kg/day with the 
possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus based on 
investigator judgment.

A4250 – IND 130591 
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Visit S-2: Screening Visit 2 (Days -28 to -7)
Patients not meeting eligibility criteria may be re-screened after consultation with the Medical 
Monitor. Patients not fulfilling inclusion/exclusion criteria after 3 attempts are not allowed to 
rescreen.
Patients will have a minimum of 12 visits at the study site and 6 scheduled telephone contacts 
(see Figure 1 and Figure 2) as follows:
Visit 1: Screening/Inclusion Visit (Day 1; coincides with Visit 9 in Study A4250-005 for 
patients in Cohort 1) 
Visit 2: Week 4 
Telephone contact 1: Week 8 
Visit 3: Week 12
Telephone contact 2: Week 18
Visit 4: Week 22
Visit 5: Week 24
Telephone contact 3: Week 30
Visit 6: Week 36
Telephone contact 4: Week 42
Visit 7: Week 46
Visit 8: Week 48
Telephone contact 5: Week 54
Visit 9: Week 60
Telephone contact 6: Week 66
Visit 10: Week 70
Visit 11: Week 72/Optional extension period
Visit 12: Follow-up Visit; Week 76 (for those not participating in optional extension period) 
Optional extension period visits every 16 weeks; Week 88 and onwards 
Additional clinic visits may be required for patients who need direct site assistance including, 
but not limited to, AE monitoring for safety maintenance.
Informed consent must be obtained prior to performing any study procedures. After signing 
the informed consent form (ICF), patients will be evaluated for study eligibility and considered 
enrolled in the study. For Cohort 1, patients who completed 24 weeks, or who withdrew after 
a minimum of 12 weeks of treatment with A4250 due to intolerable symptoms in Study A4250- 

A4250 – IND 130591 
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005 and meeting all inclusion criteria and no exclusion criteria are eligible for this study. 
Patients who withdraw from A4250-005 due to a study drug related AE will not be eligible. 
For Cohort 2, patients meeting all inclusion criteria and no exclusion criteria are eligible for 
this study. 
Patients/caregivers will be instructed to fill in the electronic diary (eDiary) every morning and 
evening for the first 24 weeks (Visit 1 through Visit 5) and the 21 days before each clinic visit 
thereafter (Visit 6 through Visit 12). In addition, Cohort 2 patients/caregivers will be instructed 
to fill in the eDiary during the screening period. Patients participating in the optional extension 
period will stop eDiary entries at Visit 11. The eDiary will include patient reported outcome 
(PRO) and observer-reported outcome (ObsRO) items for evaluation of itching (PRO), 
scratching (ObsRO), and sleep disturbance (PRO and ObsRO). Observer-reported outcomes 
in patients of all ages will be recorded by a caregiver. If possible, the same caregiver will 
complete the ObsRO items throughout the study. Additionally, caregivers will be requested to 
report in the diary the time that study drug was administered during the Treatment Period. 
The patient will return to the clinic after 4 weeks and 12 weeks and thereafter every 10 to 
12 weeks for follow-up measurements. Between the clinic visits there will be a telephone 
contact with the patient/caregiver to report AEs. 
At Visit 11, patients will be offered the choice to continue receiving A4250 treatment in an 
optional extension period. In the extension period the patient will continue to receive A4250 
at the same dose as at the end of the 72-week treatment period, returning to clinic every 16 
weeks until the drug is commercially available, provided continued use is supported by the 
risk-benefit profile and the subject has not been previously withdrawn or discontinued from 
study. 
If the patient is prematurely withdrawn from the study, all assessments scheduled for Visit 11 
will be performed at the time the patient withdraws. If a patient participating in the optional 
extension study withdraws prior to commercial drug availability, all assessments scheduled for 
the optional Extension Period End of Treatment visit will be performed. 
If a liver biopsy is performed according to the local regulations or standard of care at any time 
during A4250-008, the biopsy results should be recorded in the electronic case report form 
(eCRF). If the patient had liver biopsy results collected in study A4250-005 or prior to Week 
24 in study A4250-008, the patient will be asked to consent to a follow-up liver biopsy, if 
allowed per local regulations, at Visit 11, unless 2 prior liver biopsy results have been collected 
with at least 1 year between biopsies. Liver biopsies will not be performed in Spain. 
For those not participating in the optional extension period, Visit 12 will take place 28 days 
after Visit 11. All patients prematurely withdrawn will have this visit 28 days after the last 
dose of study drug for AE and other follow-up. 
If a patient discontinues prior to Week 72, additional telephone contacts will be made every 
3 months after the Follow-up Visit (Visit 12) up to Week 72 to gather whether or not the patient 

A4250 – IND 130591 
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has had biliary diversion or liver transplantation, and if TEAEs ongoing at the time of 
discontinuation have resolved. The telephone calls will take place up until 72 weeks even if the 
patient has biliary diversion or liver transplant. 
Details of study assessments are provided in the schedule of assessments (Table 1 and Table 2). 
Figure 1    Study Design 
 
QD: once daily; T: telephone contact; V: study visit; VS: Visit Screening 
Note: Visit 1 coincides with Visit 9 of Study A4250-005. Patients who are not tolerating the 120 µg/kg/day dose 
may be down-titrated to the 40 µg/kg/day dose following a minimum of 1 week of treatment. The patient can 
return to the higher dose as soon as deemed appropriate. 
This figure is only applicable to Cohort 2 up to Protocol Amendment 5. Figure 2 presents the study design for 
Cohort 2 as of Protocol Amendment 6. 
Figure 2    Study Design for Cohort 2 as of Protocol Amendment 6 
 
QD: once daily; T: telephone contact; V: study visit; VS: Visit Screening 
Note: As of Protocol Amendment 6, patients entering Cohort 2 will start treatment at 40 µg/kg/day with the 
possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus based on 
investigator judgment. The patient can return to the lower dose if the 120 µg/kg/day dose is not tolerated following 
a minimum of 1 week of treatment. 

A4250 – IND 130591 
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End of Study 
The end of the study is defined as follows: 
a) End of study in one country: last patient last visit (LPLV) and sites are closed. 
b) End of study globally: LPLV globally and all sites closed 
7.1.2 
Schedule of Assessments 
The schedule of assessments for the screening period through the follow-up period is presented 
in Table 1 and the schedule of assessments for the optional extension period is presented in 
Table 2. For information on blood volumes, please see Appendix 7. 

 
A4250-IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
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Table 1 
Schedule of Assessments (Screening Period through Follow-up Period) 
 
Screening 
Period (Cohort 
2 only) 
Treatment Period 
Follow- 
up 
I
Period" 
Study Activity 
Screen!ng/ I 
4 
I 
12  I 
22  I 
24  I 
36  I 
46  I 
48  I 
60  I 
70  I 
72 
I 76 weeks 
IncVl iton 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
ISi 
Study Days 
-56- 
(±window) 
(-35) 
±2 
-28- 
(-7) 
±2 
1 
28 
84 
154 
168 
252 
322 
336 
420 
490 
504 (±7) 
I 532 (±7) 
(±5) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
I 
I 
I 
I 
I 
I 
I 
I 
I 
I 
Visit 
Clinic Visits 
Visit 
Visit 
Visit I" 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
11/EOT /Start of I 
Visit 12c 
S-1 
S-2 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Optional 
Extension Period' 
Informed consent 
X 
xct 
Inclusion/exclusion 
criteria 
X 
X 
Demography/Medical 
and Surgical History 
X 
Concomitant 
medicatione 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Physical examinationr 
X 
X 
X 
X 
X 
X 
Skin examination 
X 
X 
X 
X 
X 
X 
X 
Vital signss 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
eDiary: itching, 
scratching, and sleep 
scoresh 
Daily diary entry 
For 21 days before each clinic visit for Visit 6 through Visit 12 
 
 
Confidential 
32 
Amendment 06, 21 December 2021 

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Amendment 06, 21 December 2021 
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Screening 
Period (Cohort 
2 only) 
Treatment Period 
Follow- 
up 
Period" 
Study Activity 
Screen!ng/ I 
4 
I 
12  I 
22  I 
24  I 
36  I 
46  I 
48  I 
60  I 
70  I 
72 
I  76 weeks 
IncVl iton 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
weeks 
ISi 
-56- 
-28- 
1 
28 
84 
154 
168 
252 
322 
336 
420 
490 
504 (±7) 
I 532 (±7) 
(±5) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
(±7) 
I 
I 
I 
I 
I 
I 
I 
Study Days 
(-35) 
(±window) 
±2 
(-7) 
±2 
Visit 
Clinic Visits 
Visit 
Visit 
Visit la 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
11/EOT /Start of 
I  Visit 12c 
S-1 
S-2 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Optmnal 
Extension Period' 
Fibroscan (where 
available) 
X 
X 
X 
X 
QoL questionnaire 
(PedsQL) 
X 
X 
X 
X 
Patient/Caregiver/Clin 
ician Patient Global 
Impression of Change 
X' 
X 
X 
X 
X 
X 
Patient/Caregiver/Clin 
ician Patient Global 
X 
X 
X 
X 
X 
X 
Impression of 
I 
I 
I 
I 
I 
I 
I 
I
 
Symptoms 
Pregnancy test1 
xi 
X 
xi 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Telephone contact 
Patients will be contacted via telephone for adverse event monitoring at Weeks 8, 18, 30, 42, 54, and 66 
Liver biopsy"' 
X 
Study drug dispensed11 
X 
X 
X 
X 
X 
X 
X 
X' 

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Amendment 06, 21 December 2021 
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Screening 
Period (Cohort 
2 only) 
Treatment Period 
Follow­ 
up 
Period" 
Study Activity 
Screening/ 
Inclusion 
Visit 
4 
weeks 
12 
weeks 
22 
weeks 
24 
weeks 
36 
weeks 
46 
weeks 
48 
weeks 
60 
weeks 
70 
weeks 
I 
72 
weeks 
76 weeks 
Study Days 
(±window) 
-56- 
(-35) 
±2 
-28- 
(-7) 
±2 
1 
28 
(±5) 
84 
(±7) 
154 
(±7) 
168 
(±7) 
252 
(±7) 
322 
(±7) 
336 
(±7) 
420 
(±7) 
490 
(±7) 
504 (±7) 
532 (±7) 
Clinic Visits 
Visit 
S-1 
Visit 
S-2 
Visit la 
Visit 
Visit 
Visit 
Visit 
I 
 Visit 
I 
 Visit 
Visit 
Visit 
Visit 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Visit 
11/EOT /Start of I 
Optional 
Extension Period' 
Visit 12c 
Adverse events0P 
Continuous collection 
Study drug 
compliance evaluated 
X 
xq 
X 
xq 
X 
X 
xq 
eCRF: electronic case report form; eDiary: electronic diary; EOT: end of treatment; p-C4: plasma 7a Hydroxy 4-cholesten-3-one; PedsQL: pediatric quality of life; QoL: 
quality of life. 
a 
For patients in Cohort I, Visit I coincides with Visit 9 in Study A4250-005. Assessments that have been performed at Visit 9 during Study A4250-005 will not be 
repeated. 
b 
Assessments must also be performed at the time a patient is prematurely withdrawn from the study. If a patient discontinues prior to week 72, additional phone contact 
will be made every 3 months up to a total study participation of72 weeks to assess if the patient has had biliary diversion or liver transplantation. 
c 
Assessments must be performed 28 days following the final dose of study drug. 
d 
Only for Cohort 1. 
e 
Includes current medications. 
f 
A complete physical exam will be performed at Visits S-1, 1, 3, 5, 8, and 11/EOT. 
g 
Includes blood pressure, pulse, respiratory rate, temperature, height/length (using a certified stadiometer), mid-arm circumference (3 repeat measures), and body weight 
(using a certified weight scale). Body mass index will be calculated. 

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Amendment 06, 21 December 36 I 
36 
 
 
 
Screening 
I 
Period (Cohort 
2 only) 
 
Treatment Period 
Follow­ 
up 
Period" 
Study Activity 
Screen!ng/ I 
IncVl iton 
ISi 
4 
I 
weeks 
12  I 
weeks 
22  I 
weeks 
24  I 
weeks 
36  I 
weeks 
46  I 
weeks 
48  I 
weeks 
60  I 
weeks 
70 
weeks 
72 
weeks 
76 weeks 
Study Days 
(±window) 
-56- 
(-35) 
±2  I 
-28- 
(-7) 
±2 
1 
I 
28 
(±5)  I 
84 
(±7) 
154 
(±7) 
168 
(±7)  I 
252 
(±7)  I 
322 
(±7)  I 
336 
(±7)  I 
420 
(±7) 
490 
(±7) 
504 (±7) 
532 (±7) 
Clinic Visits 
Visit 
S-1 
Visit 
Visit la 
S-2 
Visit 
2 
Visit 
3 
Visit 
4 
Visit 
5 
Visit 
6 
Visit 
7 
Visit 
8 
Visit 
9 
Visit 
10 
Visit 
11/EOTb/Start of 
Optional 
Extension Period' 
Visit 12c 
h 
Itching, scratching, and sleep will be assessed via an eDiary (issued with any necessary training to patients/caregivers at Visit I). Patients/caregivers will be instructed 
to fill in the eDiary every morning and evening for the first 24 weeks and the last 21 days before all the remaining visits to the clinic. There will be no interruption 
between Visits 11 and 12. Patients participating in the extension period will stop eDiary entries at Visit 11. 
See Table 4 for detailed parameters. 
j 
Patients will fast (only water intake is permissible) for at least 4 hours prior to the collection of samples for serum bile acids and vitamin A. Exceptions can be made for 
infants, less than 12 months of age, if unable to fast for the entire 4 hours. 
k 
Autotaxin and p-C4 samples will not be collected for patients :S 10 kg. 
For girls who have reached menarche. Serum test will be performed at Visit S-1 for Cohort 2 only and Visit I (for Cohort I only); urine test will be performed at all 
other visits. If a urine pregnancy test is positive, a serum pregnancy test should be performed to confirm the pregnancy. 
m 
If a liver biopsy is performed at any time during A4250-008 according to the local regulations or standard of care, the biopsy results should be recorded in the eCRF. If 
the patient has liver biopsy results collected in study A4250-005 or prior to Week 24 in study A4250-008, the patient will be asked to consent to a follow up liver 
biopsy, if allowed per local regulations, at Visit 11 unless 2 prior liver biopsy results have been collected with at least l year between biopsies. Liver biopsies will not 
be performed in Spain. 
n 
Study drug will be taken once daily from Day I through Day 504 as described in Section 8.2. 
o 
Adverse event information will be collected from the time of signing of the informed consent form to study discontinuation. 
p 
For hepatic adverse events and/or hepatic decompensation, a PK sample should be collected as close to the onset of the event as possible (PK samples not required 
during screening period). 
q 
Dosage form acceptability questions will be asked of the caregiver and/or patient at Visits 3, 6, and 11. 

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Amendment 06, 21 December 2021 
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Screening 
Period (Cohort 
2 only) 
Treatment Period 
Follow­ 
up 
Period" 
Study Activity 
Screening/ 
Inclusion 
Visit 
4 
weeks 
12 
weeks 
22 
weeks 
24 
weeks 
36 
weeks 
46 
weeks 
48 
weeks 
60 
weeks 
70 
weeks 
I 
72 
weeks 
76 weeks 
Study Days 
(±window) 
-56- 
(-35) 
-28- 
(-7) 
±2 
1 
28 
(±5) 
84 
(±7) 
154 
(±7) 
168 
(±7) 
252 
(±7) 
322 
(±7) 
336 
(±7) 
420 
(±7) 
490 
(±7) 
504 (±7) 
532 (±7) 
±2 
Clinic Visits 
Visit 
S-1 
Visit 
S-2 
Visit la 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
Visit 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Visit 
11/EOT /Start of I 
Optional 
Extension Period' 
Visit 12c 
r 
Patient/Caregiver/Clinician Patient Global Impression of Change not applicable for Cohort 2. 
s 
Patients who wish to continue receiving A4250 after 72 weeks, will have the option to remain on treatment in an optional extension period until the drug is 
commercially available, provided continued use is supported by the risk-benefit profile and the patient has not been previously withdrawn or discontinued from study. 
Dispensation only for patients moving into the optional extension period. 
u 
Only for patients who stop treatment at 72 weeks. 

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Table 2 
Schedule of Assessments (Optional Extension Period) 
 
Extension Period 
Extension Period EOT 
Study Activity 
Every 16 weeks 
Study Days (±window) 
Every 112 days (±7) 
Concomitant medication" 
X 
X 
Vital signsb 
X 
X 
Clinical chemistryc 
X 
X 
Serum bile acidsd 
X 
X 
Vitamins Ad, E, and 25-hydroxy vitamin D 
X 
X 
International normalized ratio 
X 
X 
Urine pregnancye 
X 
X 
Adverse eventsr 
X 
X 
Study drug compliance evaluated 
X 
X 
Study drug dispensedg 
X 
QoL questionnaire (PedsQL) 
X 
X 
Patient/Caregiver/Clinician Patient Global Impression of Change 
X 
X 
Patient/Caregiver/Clinician Patient Global Impression of Symptoms 
X 
X 
a Includes current medications. 
b Includes blood pressure, pulse, respiratory rate, temperature, height/length (using a certified stadiometer), mid-arm circumference (3 repeat measures), and body weight (using a certified 
weight scale). Body mass index will be calculated. 
c See Table 4 for detailed parameters. 
d Patients will fast (only water intake is permissible) for at least 4 hours prior to the collection of samples for serum bile acids and vitamin A. 
e For girls who have reached menarche. 
f For hepatic adverse events and/or liver decompensation, a PK sample should be collected as close to the onset of the event as possible 

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Extension Period 
Extension Period EOT 
Study Activity 
Every 16 weeks 
Study Days (±window) 
Every 112 days (±7) 
g Study drug will be taken once daily throughout the extension period. 

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7.1.3
Study Procedures and Assessments
When the COVID-19 pandemic makes it challenging for a patient to attend a visit at the study 
center and where applicable country and local regulations and infrastructure allow, routine 
assessments may be performed outside of the study center (e.g., the patient’s home) by a trained 
healthcare professional at all timepoints following the Inclusion Visit (Visit 1). These 
assessments can include the following: vital signs, height and weight, mid-arm circumference, 
body assessement, blood draws, urine collection, and urine pregnancy test. All laboratory 
samples should be sent to the central laboratory; an exception is for situations related to the 
COVID-19 pandemic if central laboratory assessments are not possible, then a local laboratory 
may be used. These local laboratory results must be sent to the site for review by the
investigator and submitted to iRIS (ICON Results Integration Services). Collection of other
visit requirements, e.g., concomitant medication and AE collection associated with visits
outside of the clinic will be collected by qualified site staff through verbal contact with the 
patient.
For any study visit, the study physician (or delegate) must, at a minimum, verbally contact the 
patient within the expected window for each study visit to collect relevant safety information 
(including, but not limited to, AEs, concomitant medications, hospitalizations/procedures, and 
vital status). Any missed assessment due to a study visit being performed outside of the study 
center will be considered a protocol deviation.
7.1.3.1
Screening Period (Days -56 to 0) (For Cohort 2 only)
If the screening period is expected to be prolonged due to COVID-19 related issues, site follow- 
up with the medical monitor and investigator is required to determine if the screening period
can be extended for another 2 weeks. Determination will be assessed on a case-by-case basis. 
During this allowed two-week extension period, it is anticipated that no additional testing and 
assessments will be required. If the screening period is extended beyond two weeks, additional 
assessments, including but not limited to safety labs, will be required.
Day -56 to Day -35/Clinic Visit S-1 
Cohort 2 patients will undergo a Screening Visit up to 56 days prior to the planned first day of 
study treatment. Screening procedures and assessments are as follows:
Obtain written informed consent
Assess inclusion/exclusion criteria (Section 7.2)
Record demographics
Document concomitant medications
Medical and surgical history (date of diagnosis of PFIC Type, prior investigational 
medications for PFIC, historical liver function test [LFT] values, any surgery performed,
any other diagnosis, and historical liver biopsy data) 

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Amendment 06, 21 December 2021
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For patients with episodic forms of PFIC (i.e., BRIC), collect information on frequency, 
duration, and severity of flares within the last 6 months at a minimum, and within the last 
5 years, if possible. If available, historical data on serum bile acid levels and pruritus should 
be collected
Collect, if available, past confirmatory clinical genetic laboratory report for PFIC,
including BRIC, type and send to central reader for review. If a historical report is 
equivocal, unavailable, or unobtainable, a blood sample for clinical genetic testing will be 
collected to determine eligibility (Section 10.2.4)
Physical examination (Section 10.2.5) and vital signs (Section 10.2.6)
Skin examination (Section 10.2.5)
eDiary training and compliance requirements; caregivers and/or patients begin daily 
recording of pruritus using the eDiary (Appendix 2)
Clinical chemistry (Section 10.2.1)
Serum bile acids (Section 9.2.1)
Serum pregnancy test for girls who have reached menarche. Please see Appendix 6 for 
contraceptive requirements
AE monitoring
Day -28 to Day -7/Clinic Visit S-2 
A second Screening Visit will be performed for patients in Cohort 2. Screening procedures 
and assessments are as follows:
Review concomitant medications 
 
Vital signs (Section 10.2.6)
Albireo PRO/ObsRO eDiary review for compliance
Serum bile acids (Section 9.2.1)
International normalized ratio (INR)
Urine pregnancy test for girls of who have reached menarche
 
AE monitoring 
Clinical chemistry retest (if applicable)
7.1.3.2
Treatment Period 
Study Day 1/Visit 1
For Cohort 1, patients will undergo a Screening/Inclusion Visit that coincides with Visit 9 of 
Study A4250-005. 

A4250 – IND 130591 
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Amendment 06, 21 December 2021
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For Cohort 1: Obtain written informed consent
For Cohort 2: Albireo PRO/ObsRO eDiary review for compliance and eligibility criteria (see 
Inclusion Criteria 4 [Cohort 2, excluding BRIC], Section 7.2.1). 
The following procedures will be conducted for both cohorts:
Assess inclusion/exclusion criteria (Section 7.2)
Document concomitant medications
Physical examination (Section 10.2.5) and vital signs (Section 10.2.6)
Skin examination (Section 10.2.5)
Albireo PRO/ObsRO eDiary training, compliance requirements, and instructions to 
continue recording of pruritus (Appendix 2)
Clinical chemistry, hematology, and urinalysis (Section 10.2.1)
Serum bile acids (Section 9.2.1)
p-C4 and autotaxin
Alfa-fetoprotein (AFP)
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1) 
Abdominal ultrasound (Section 10.2.7)
Fibroscan, where available (Section 9.2.8)
Administer QoL (Pediatric Quality of Life Inventory [PedsQL]) questionnaire
Serum pregnancy test for girls who have reached menarche (only for patients in Cohort 1).
Please see Appendix 6 for contraceptive requirements
Patient/caregiver/clinician complete the patient global impression of symptoms (PGIS) and 
the patient global impression of change (PGIC) 
AE monitoring
Study drug is dispensed
Week 4/Visit 2 
The following procedures and assessments will be conducted: 
Document concomitant medications
Vital signs (Section 10.2.6)
Skin examination (Section 10.2.5)
Albireo PRO/ObsRO eDiary review for compliance

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Clinical chemistry and hematology (Section 10.2.1)
INR
Serum bile acids (Section 9.2.1)
p-C4 and autotaxin 
Patient/caregiver/clinician complete the PGIS and the PGIC
Urine pregnancy test for girls who have reached menarche
AE monitoring
Evaluation of study drug compliance 
 
Study drug is dispensed 
Week 8/Telephone contact 1 
A study nurse will contact patients via telephone for AE monitoring 4 weeks after Visit 2,
at Week 8
Week 12/Visit 3 
As of Protocol Amendment 6, patients entering Cohort 2 will start treatment at 40 µg/kg/day 
with the possibility to dose escalate to 120 µg/kg/day after 12 weeks (Visit 3) if there is no 
improvement in pruritus based on investigator judgment. 
The following procedures and assessments will be conducted (all patients): 
Document concomitant medications
Physical examination (Section 10.2.5) and vital signs (Section 10.2.6)
Skin examination (Section 10.2.5)
Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry and hematology (Section 10.2.1) 
INR
Serum bile acids (Section 9.2.1)
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1) 
Patient/caregiver/clinician complete the PGIS and the PGIC
Urine pregnancy test for girls who have reached menarche
AE monitoring
Evaluation of study drug compliance; dosage form acceptability questions will be asked of 
the caregiver and/or patient

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Study drug is dispensed
Week 18/Telephone contact 2 
A study nurse will contact patients via telephone for AE monitoring 6 weeks after Visit 3,
at Week 18
Weeks 22 and 46/Visits 4 and 7 
The following procedures and assessments will be conducted: 
Document concomitant medications
Vital signs (Section 10.2.6)
Albireo PRO/ObsRO eDiary review for compliance
INR
Serum bile acids (Section 9.2.1)
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1)
Urine pregnancy test for girls who have reached menarche
 
AE monitoring 
Weeks 24 and 48/Visits 5 and 8 
The following procedures and assessments will be conducted:
Document concomitant medications
Skin examination (Section 10.2.5)
Physical examination at Visit 5 (Section 10.2.5) and vital signs (Section 10.2.6) 
Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry, hematology, and urinalysis (Section 10.2.1) 
Serum bile acids (Section 9.2.1)
p-C4 and autotaxin 
AFP
Abdominal ultrasound (Section 10.2.7)
Fibroscan, where available (Section 9.2.8)
Administer PedsQL questionnaire
Patient/caregiver/clinician complete the PGIS and the PGIC
Urine pregnancy test for girls who have reached menarche
AE monitoring

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Amendment 06, 21 December 2021
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Evaluation of study drug compliance 
 
Study drug is dispensed 
Weeks 30 and 54/Telephone contacts 3 and 5 
A study nurse will contact patients via telephone for AE monitoring 6 weeks after Visits 5 
and 8, at Weeks 30 and 54, respectively 
Weeks 36 and 60/Visits 6 and 9 
The following procedures and assessments will be conducted:
Document concomitant medications 
Vital signs (Section 10.2.6)
Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry and hematology (Section 10.2.1)
INR
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1) 
Serum bile acids (Section 9.2.1)
Urine pregnancy test for girls who have reached menarche
 
AE monitoring 
Evaluation of study drug compliance; dosage form acceptability questions will be asked of 
the caregiver and/or patient (only at Visit 6) 
Study drug is dispensed
Weeks 42 and 66/Telephone contacts 4 and 6 
A study nurse will contact patients via telephone for AE monitoring 6 weeks after Visits 6 
and 9, at Weeks 42 and 66, respectively 
Week 70/Visit 10
The following procedures and assessments will be conducted: 
Document concomitant medications
Vital signs (Section 10.2.6)
Albireo PRO/ObsRO eDiary review for compliance
Serum bile acids (Section 9.2.1)
INR
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1)

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Amendment 06, 21 December 2021
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Urine pregnancy test for girls who have reached menarche
 
AE monitoring 
7.1.3.3
End of Treatment/Early Termination/Start of Optional Extension Period 
Week 72/Visit 11
The last dose of study drug will be administered in the morning the day before the visit and the 
following assessments will be performed:
Document concomitant medications
Physical examination (Section 10.2.5) and vital signs (Section 10.2.6)
Skin examination (Section 10.2.5)
Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry, hematology, and urinalysis (Section 10.2.1)
Serum bile acids (Section 9.2.1)
p-C4 and autotaxin 
AFP
Abdominal ultrasound (Section 10.2.7)
Fibroscan, where available (Section 9.2.8)
Administer PedsQL questionnaire
Urine pregnancy test for girls who have reached menarche
Patient/caregiver/clinician complete the PGIC and PGIS
AE monitoring
Evaluation of study drug compliance; dosage form acceptability questions will be asked of 
the caregiver and/or patient
Liver biopsy (if required; see Section 9.2.10)
Patient/Caregiver decide whether to continue A4250 treatment 
 
Dispensing of drug for optional Extension Period (if applicable) 
7.1.3.4
Follow-up Visit
Week 76/Visit 12 (Patients/Caregivers not participating in Optional Extension Period)
Patients will return to the study site 28 days after Visit 11 or the last dose of study drug (for 
those patients who prematurely withdraw) for the following assessments: 
Document concomitant medications

A4250 – IND 130591 
EudraCT 2017-002325-38
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Amendment 06, 21 December 2021
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Vital signs (Section 10.2.6)
Albireo PRO/ObsRO eDiary review for compliance
Clinical chemistry and hematology (Section 10.2.1)
INR
Serum bile acids (Section 9.2.1)
Urine pregnancy test for girls who have reached menarche
 
AE monitoring 
7.1.3.5
Optional Extension Period
Week 88 and every 16 weeks thereafter up to commercial availability of drug
Document concomitant medications 
 
Vital signs (Section 10.2.6)
Clinical Chemistry (Section 10.2.1) 
Serum bile acids (Section 9.2.1)
Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1) 
INR
Urine pregnancy test for girls who have reached menarche
Administer PedsQL questionnaire
Patient/caregiver/clinician complete the PGIS and the PGIC
 
Evaluation of study drug compliance 
Study drug is dispensed 
 
AE monitoring 
7.1.3.6
Optional Extension Period End of Treatment
Upon commercial availability, patients should complete the End of Treatment (EOT) visit 
before starting commercial drug. For patients who decide to withdraw from the optional 
extension period prior to commercial availability, patients should immediately return to the site 
for the following EOT assessments:
Document concomitant medications 
Vital signs (Section 10.2.6)
Clinical Chemistry (Section 10.2.1) 
Serum bile acids (Section 9.2.1)

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Amendment 06, 21 December 2021
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Vitamins A, E, and 25-hydroxy vitamin D (Section 10.2.1)
INR
Urine pregnancy test for girls who have reached menarche 
Administer PedsQL questionnaire 
Patient/caregiver/clinician complete the PGIS and the PGIC 
Evaluation of study drug compliance 
AE monitoring
7.2
Study Population
Cohort 1 will consist of approximately 60 children who completed 24 weeks, or who withdrew 
after a minimum of 12 weeks of treatment due to intolerable symptoms in Study A4250-005 
and meeting all inclusion criteria and no exclusion criteria are eligible for this study. Patients 
who withdraw from A4250-005 due to a study drug related AE will not be eligible. 
Cohort 2 will consist of approximately 60 patients with any type of PFIC who have elevated 
serum bile acids and cholestatic pruritus and who either (1) do not meet eligibility criteria for 
Study A4250-005 (PEDFIC 1) or (2) do meet the eligibility criteria for A4250-005 after 
recruitment of study A4250-005 has been completed. Up to 40 patients post biliary diversion 
surgery are allowed to participate in Cohort 2.
7.2.1
Inclusion Criteria
Cohort 1:
1. Completion of the 24-week Treatment Period of Study A4250-005 or withdrawn from
Study A4250-005 due to patient/caregiver judgment of intolerable symptoms after 
completing at least 12 weeks of treatment. Patients who withdraw from A4250-005 due to
a study drug related AE will not be eligible. 
2. Signed informed consent and assent as appropriate. Patients who turn 18 years of age (or 
legal age per country) during the study will be required to re-consent to remain on the study. 
3. Patients expected to have a consistent caregiver for the duration of the study.
4. Caregivers (and age-appropriate patients) must be willing and able to use an eDiary device 
as required by the study. 
Cohort 2:
1. A male or female patient of any age, with a clinical diagnosis of PFIC, including episodic 
forms (i.e., BRIC), and with a body weight 5 kg at Visit S-1.
2. Patient must have clinical genetic confirmation of PFIC.

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3. Patients with PFIC, excluding BRIC, must have elevated serum bile acid concentration,
s at least 7 days
apart (Visits S-1 and S-2) prior to the Screening/Inclusion Visit (Visit 1).
4. Patients with PFIC, excluding BRIC, must have history of significant pruritus and a 
caregiver-reported observed scratching or patient-reported itching (for patients >18 with no 
caregiver-reported observed scratching) 
2 weeks prior to the Screening/Inclusion Visit (Visit 1). 
5. Patients with episodic forms of PFIC (i.e., BRIC) must have an emerging flare
characterized by clinically significant pruritus and elevated serum bile acid
levels/cholestasis as judged by the investigator.
6. Patient and/or legal guardian must sign informed consent (and assent) as appropriate. 
Patients who turn 18 years of age (or legal age per country) during the study will be required 
to re-consent in order to remain in the study. 
7. Age appropriate patients are expected to have a consistent caregiver for the duration of the 
study.
8. Caregivers and age-
, if able) must be willing and able 
to use an eDiary device as required by the study. 
7.2.2
Exclusion Criteria
Patients meeting any of the following criteria at Visit 1 or Visit S-1 will not be eligible for 
study participation:
Cohort 1:
1. Decompensated liver disease: coagulopathy, history, or presence of clinically significant 
ascites, variceal hemorrhage, and/or encephalopathy. 
2. Sexually active males and females who are not using a reliable contraceptive method with
-uterine device, or complete 
abstinence) throughout the duration of the study and 90 days thereafter (from signed 
informed consent through 90 days after last dose of study drug). See Appendix 6 for further 
details.
3. Patients not compliant with treatment in study A4250-005.
4. Any other conditions or abnormalities which, in the opinion of the investigator or Medical 
Monitor, may compromise the safety of the patient, or interfere with the patient
participating in or completing the study. 
Cohort 2:
1. Known pathologic variations of the ABCB11 gene that have been demonstrated to result 
in complete absence of the BSEP protein.

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2. Patient with past medical history or ongoing presence of other types of liver disease 
including, but not limited to, the following: 
a) Biliary atresia of any kind.
b) Suspected or proven liver cancer or metastasis to the liver on imaging studies.
c) Histopathology on liver biopsy is suggestive of alternate non-PFIC related etiology of
cholestasis.
Note: Patients with clinically significant portal hypertension are allowed.
3. Patient with a past medical history or ongoing presence of any other disease or condition 
known to interfere with the absorption, distribution, metabolism (specifically bile acid 
metabolism), or excretion of drugs in the intestine, including but not limited to, 
inflammatory bowel disease.
4. Patient with past medical history or ongoing chronic (i.e., >3 months) diarrhea requiring 
intravenous fluid or nutritional intervention for treatment of the diarrhea and/or its 
sequelae.
5. Patient has a confirmed past diagnosis of infection with human immunodeficiency virus 
or other present and active, clinically significant, acute, or chronic infection, or past 
medical history of any major episode of infection requiring hospitalization or treatment 
with parenteral anti-infective treatment within 4 weeks of treatment start (Study Day 1) or 
completion of oral anti-infective treatment within 2 weeks prior to start of Screening
Period.
6. Any patient with suspected or confirmed cancers except for basal cell carcinoma, and 
non-liver cancers treated at least 5 years prior to Screening with no evidence of recurrence.
7. Patient has had a liver transplant, or a liver transplant is planned within 6 months of the 
Screening/Inclusion Visit. 
8. Decompensated liver disease, coagulopathy, history, or presence of clinically significant 
ascites, variceal hemorrhage, and/or encephalopathy. 
9. INR >1.4 (the patient may be treated with Vitamin K intravenously, and 
resampling the patient may be included).
10. Serum ALT >10 × upper limit of normal (ULN) at Screening.
11. Serum ALT >15 × ULN at any time point during the last 6 months unless an alternate 
etiology was confirmed for the elevation. 
12. Total bilirubin >10 × ULN at Screening.
13. Patient suffers from uncontrolled, recalcitrant pruritic condition other than PFIC. 
Examples include, but not limited to, refractory atopic dermatitis or other primary pruritic 
skin diseases.

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14. Any patient who is pregnant or lactating or who is planning to become pregnant within 
72 weeks of the Screening/Inclusion Visit. 
15. Sexually active males and females who are not using a reliable contraceptive method with
complete 
abstinence) throughout the duration of the study and 90 days thereafter (from signed 
informed consent through 90 days after last dose of study drug). See Appendix 6 for 
further details.
16. Patient with a past medical history of alcohol or substance abuse will be excluded. 
Patient must agree to refrain from illicit drug and alcohol use during the study. 
17. Administration of bile acid or lipid binding resins and medications that slow GI motility 
(Refer to Appendix 1 – Concomitant Medications Guidelines).
18. Patient has had investigational exposure to a drug, biologic agent, or medical device
within 30 days prior to Screening, or 5 half-lives of the study agent, whichever is longer. 
19. Any other conditions or abnormalities which, in the opinion of the investigator or Medical 
Monitor, may compromise the safety of the patient, or interfere with the patient
participating in or completing the study. 
7.2.3
Withdrawal of Patients
Patients/caregivers will be informed that they have the right to withdraw from the study at any 
time, without prejudice to their medical care, and that they are not obliged to state their reasons.
Any withdrawal, and reasons for withdrawal, must be fully documented in the eCRF and source 
documents and the patient followed by the investigator/investigative staff. Withdrawn patients 
will not be replaced.
Patients will be withdrawn in the following circumstances:
A patient’s/caregiver’s desire for withdrawal for any reason
Lost to follow-up (every effort must be made to contact the patient/caregiver; a certified 
letter must be sent)
An AE which, in the opinion of the investigator, necessitates withdrawal 
Death
A patient’s/caregiver’s substantial non-compliance (eDiary and study drug compliance) or 
protocol violation
An investigator’s opinion that continuing the patient in the study is not appropriate. The 
investigator may withdraw a patient at any time, if it is considered to be in the patient’s best 
interest
Liver transplantation

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The reason and the date the patient is withdrawn from the study will be documented in the 
eCRF and source documents. If a patient is withdrawn from further treatment with the study 
drug, the investigator/investigative staff will attempt to complete all Visit 11 procedures at the 
time the patient is prematurely withdrawn from the study. The investigator/investigative staff 
will also attempt to complete all Visit 12 procedures 28 days following premature withdrawal 
(i.e., 28 days following the final dose of the study drug). 
If a patient discontinues prior to Week 72, additional telephone contacts will be made every 
3 months after the Follow-up Visit (Visit 12) up to Week 72 to gather whether or not the patient 
has had biliary diversion or liver transplantation, and of ongoing TEAEs at the time of 
discontinuation have resolved. The telephone calls will take place up until 72 weeks even if the 
patient has biliary diversion or liver transplant. 
7.2.4 
Study Termination by Sponsor 
This study may be terminated at any time by Albireo if significant safety concerns develop or, 
in the sponsor’s judgment, there are no further benefits to be achieved from continuation of the 
study. In this event, Albireo/designee will inform the study investigators, institutions and all 
regulatory authorities. 
Albireo may temporarily or permanently discontinue the study at an investigative site at any 
time for safety, ethical, compliance or other reasons. If this is necessary, Albireo will endeavor 
to provide advance notification to the site. If a site or the study is suspended or discontinued, 
the investigator/investigative staff will be responsible for promptly informing the Independent 
Ethics Committee (IEC)/Institutional Review Board (IRB) that this has happened. If required 
by local regulations, Albireo/designee will be responsible for informing the IEC/IRB and the 
Regulatory Authority of study or site discontinuation. In such an event, all study data and 
unused study drug must be returned to Albireo. 

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8
TREATMENT OF PATIENTS
8.1
Identity of Study Drug
A4250 will be supplied as capsules for oral administration. White opaque capsules filled with 
pellets containing A4250 will be provided. Two different capsule sizes will be available:
Capsule size 0 that can be opened
Capsule size 3 that should be swallowed intact. The size 3 capsules may be opened
only under exceptional circumstances, e.g., patient cannot swallow the capsule intact. 
Bottles with 34 capsules will be given to the patient at each visit. A patient who requires 2 or 
more capsules per day will be given multiple bottles. Refer to the Investigational Product 
Manual.
A 5-digit study drug number will identify study drug packs and will be detailed on the study 
drug label. Dispensing of study drug will be coordinated by the Interactive Web Response 
System (IWRS). The system will assign study drug number(s) using a packing list based on 
the patient’s weight and dose level (either 120 µg/kg/day or 40 µg/kg/day) for dispensation at 
each dispensing visit. In case of technical issues accessing the system online, please see the 
IWRS site user manual for country-specific contact telephone numbers to the ICON HelpDesk 
24/7 system support. 
8.2
Administration of Study Drug
Patients will be dosed with 120 µg/kg/day or 40 µg/kg/day4 for 72 weeks or 40 µg/kg/day for
the first 12 weeks followed by 120 µg/kg/day for the remaining 60 weeks4. Patients not 
tolerating the 120 µg/kg/day dose after a minimum of 1 week, for reasons other than new liver 
findings and severe diarrhea, will have the option to down-titrate to a lower dose 
(40 µg/kg/day). They should return to the higher dose as soon as deemed appropriate by the 
investigator.  More than one upward dose titration (from 40 µg/kg/day directly to
120 µg/kg/day) for the same event is not recommended. If, in the opinion of the investigator, 
a dose titration should be considered prior to the 1 week minimum, the investigator should 
consult with the Medical Monitor or designee.
Any dose titration should be done in 
consultation with the sponsor Medical Monitor or designee. 
Study drug will be dispensed to the patient at defined intervals from Visit 1 through Visit 9, 
together with instructions on how to store and take the drug. Study drug administration data, 
including whether each patient took each dose or partial doses of study drug, whether there
were any delayed or missed doses, and whether the capsule was opened or swallowed whole, 
will be documented through the diaries and transferred to the study database. 
4 As of Protocol Amendment 6 patients entering Cohort 2 will start treatment at 40 µg/kg/day with the 
possibility to dose escalate to 120 µg/kg/day after 12 weeks if there is no improvement in pruritus based on 
investigator judgment.

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Patients participating in the optional extension period will continue at the same dose as at the 
end of the 72-week treatment period (120 µg/kg/day or 40 µg/kg/day). Patients not tolerating 
the 120 µg/kg/day dose at any time throughout the extension period will have the option to 
down-titrate to a lower dose (40 µg/kg/day) following consultation with the sponsor Medical 
Monitor or designee. Patients should return to the higher dose as soon as deemed appropriate 
by the investigator. More than one upward dose titration (from 40 µg/kg/day directly to 
120 µg/kg/day) for the same event is not recommended. 
A4250 should be taken in the morning together with food. On clinic visits days when 
laboratory assessments are conducted (Visits 1 to 10; or Visits 1 to XX for those participating 
in the optional extension period), study drug should be taken after the visit. Patients should 
not crush or chew the capsule(s). When swallowing the capsule intact, the patient should 
administer the dose with a glass of water. 
If the study medicine needs to be mixed in a small amount of food because the patient is unable 
to swallow the capsule intact, the capsule can be twisted open and the contents sprinkled and 
mixed in a small amount (one or two tablespoons (15 to 30 mL)) of room-temperature yogurt, 
apple sauce, oatmeal, or fruit purée. If the patient has not yet been weaned onto solid foods, 
the capsule contents can be sprinkled into a small amount (a few milliliters) of water, baby 
formula or breast milk and administered with an oral dosing pipette. Please see Pharmacy 
manual for detailed instructions. 
If a patient’s weight changes at any time during the study, dose adjustment will be required. 
The number of capsules provided to the patient should be based on the body weight thresholds 
identified in Table 3. 

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Table 3 
Dosing and Capsule Strength 
 
Body 
Weight (kg) 
Capsule 
Size 
Number of 
Capsules 
per Daya,b 
Capsule 
Strength, 
Low Dosea 
(µg) 
Total Dose 
(µg) a 
Capsule 
Strength, 
High Doseb 
(µg) 
Total Dose 
(µg) b 
5 to <7.5 
0 
1 
200 
200 
600 
600 
7.5 to <12.5 
0 
2 
200 
400 
600 
1200 
12.5 to <17.5 
0 
3 
200 
600 
600 
1800 
17.5 to <19.5 
0 
4 
200 
800 
600 
2400 
19.5 to <25.5 
3 
2 
400 
800 
1200 
2400 
25.5 to <35.5 
3 
3 
400 
1200 
1200 
3600 
35.5 to <45.5 
3 
4 
400 
1600 
1200 
4800 
45.5 to 55.5 
3 
5 
400 
2000 
1200 
6000 
>55.5 
3 
6 
400 
2400 
1200 
7200 
a Low dose: 40 µg/kg/day 
b High dose: 120 µg/kg/day 

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8.3 
Study Drug Packaging and Labelling 
8.3.1 
Packaging and Labelling 
The capsules will be packed in high-density polyethylene containers, with childproof 
polypropylene caps. Study drug capsules containing A4250 in the strength specified in the 
table above will be manufactured. 
Packaging and labelling will be prepared to comply with applicable regulatory requirements. 
8.3.2 
Storage 
Treatment packs containing A4250 capsules should be stored and dispensed in accordance with 
regulations in their original containers. The storage facility at the investigative site should be 
locked and storage should be between 15°C and 25°C. 
Patients/caregivers should be informed of appropriate storage conditions (i.e., room 
temperature, between 15°C and 25°C). 
Any deviations from the recommended storage conditions should be immediately reported to 
Albireo and the study drug should not be used until authorization has been given by Albireo. 
8.3.3 
Blinding and Randomization of Study Drug 
Not applicable. 
8.4 
Procedure for Breaking the Randomization Code 
Not applicable. 
8.5 
Patient Compliance 
The study nurse will monitor eDiary compliance by routine review of the CRF Health website. 
Patient/caregivers will be instructed to fill in the eDiary every morning and evening for the first 
24 weeks and the last 21 days before all the remaining visits to the clinic. There will be no 
interruption between Visits 11 and 12. Patients participating in the optional extension period 
will stop eDiary entries at Visit 11. If both diary entries on a day are missing during this time, 
the study nurse will call the caregiver/patient to remind them to complete all scheduled entries. 
Any non-compliance will be documented and explained in the source documents. 
Study drug compliance will be assessed by review of returned unused medication and by 
counting returned capsules at Visits 2 through 11 or Visits 2 through XX if participating in the 
optional extension phase, inclusive. Study drug compliance will be calculated for each patient 
and listed. 
Treatment Compliance = 100 × ((Number of study drug dispensed - number of study drug 
returned)/number of study drug that should be taken) 
Treatment compliance between 80% and 120% will be acceptable. 

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8.6 
Patient Identification 
After written informed consent is obtained from an eligible patient, an 8-digit patient 
identification number will be assigned. The first 2 digits will denote the country, followed by 
a 3-digit site number and a 3-digit patient sequence number. This number will be captured by 
the IWRS, when the patient first enters the system in A4250-008. Cohort 1 patients will be 
assigned the same patient number as used in the A4250-005 study, while Cohort 2 patients will 
be assigned a new unique patient number. 
8.7 
Study Drug Accountability 
Records shall be maintained of the delivery of study treatment to the study site(s), the inventory 
at the study site(s), the use of each patient and the return to Albireo. 
These records shall include dates, quantities, batch numbers, expiry dates and the unique code 
numbers assigned to the study drug and to the study patients. 
The investigator will be responsible for ensuring that the records adequately document that the 
patients were provided the quantities specified in the protocol and that all study drug received 
from Albireo is reconciled. 
8.8 
Concomitant Therapy and Prohibited Medications 
For Cohort 1 patients, the investigator will note all ongoing medication in the eCRF at Visit 1. 
For Cohort 2 patients, the investigator will note all ongoing medication and any medication 
recently stopped (within 1 month prior to Visit S-1) in the eCRF at Visit S-1. At Visits 2 to 
12, (and S-2 for Cohort 2) and visits in the optional extension period, all changes in medication 
(stopping or starting new medication or changes in dose) will be recorded in the eCRF. All 
medication (prescribed or over the counter) for pruritus, sleep, and vitamin supplementation 
will be recorded. 
All medications still being taken by a patient on or after first intake of study drug and which 
continue to be taken during the study are regarded as concomitant medication. 
The protocol allows for patients to be vaccinated against COVID-19 while in the study, based 
on the treating physician’s clinical assessment of the risks and benefits of study participation. 
Therefore, the COVID-19 vaccine can be administered as a concomitant medication. The date 
of COVID-19 vaccination must be recorded in the clinical database if administered during 
study participation. 
Concomitant medication guidelines are listed in Appendix 1. 

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9
ASSESSMENT OF EFFICACY
9.1
Efficacy Endpoints
9.1.1
Primary Efficacy Endpoints
The primary efficacy endpoints are:
EU and rest of world: Change from baseline in serum bile acids after 72 weeks of treatment.
US: Proportion of positive pruritus assessments at the patient level over the 72-week treatment 
period using the Albireo ObsRO instrument. 
9.1.2
Secondary Efficacy Endpoints
EU and rest of world: Proportion of positive pruritus assessments at the patient level over 
the 72-week treatment period using the Albireo ObsRO instrument. 
US: Change from baseline in serum bile acidsafter 72 weeks of treatment.
All Regions:
Change from baseline in serum bile acids at Weeks 4, 12, 22, 24, 36, 46, 48, 60, 70, 72, and
76
Proportion of individual assessments meeting the definition of a positive pruritus
assessment at the patient level using the Albireo ObsRO instrument from Weeks 0-4, 
Weeks 0-12, Weeks 0-22, Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, 
Weeks 0-60, and Weeks 0-70, respectively, or the proportion of positive pruritus 
assessments at each 4-week interval between Visit 1/Screening and Visit 5/Week 24, then
by each visit between Visit 5/Week 24 to Visit 12/Week 76 
Proportion of individual AM assessments meeting the definition of a positive pruritus 
assessment at the patient level using the Albireo ObsRO instrument from Weeks 0-4, 
Weeks 0-12, Weeks 0-22, Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, 
Weeks 0-60, Weeks 0-70, and Weeks 0-72, respectively, or the proportion of positive 
pruritus  assessments
at  each
4-week
interval  between
Visit
1/Screening
and 
Visit 5/Week 24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 
Proportion of individual PM assessments meeting the definition of a positive pruritus 
assessment at the patient level using the Albireo ObsRO instrument from Weeks 0-4, 
Weeks 0-12, Weeks 0-22, Weeks 0-24, Weeks 0-36, Weeks 0-46, Weeks 0-48, 
Weeks 0-60, Weeks 0-70, and Weeks 0-72, respectively, or the proportion of positive 
pruritus  assessments
at  each
4-week
interval  between
Visit
1/Screening
and 
Visit 5/Week 24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 
All-cause mortality, number of patients undergoing biliary diversion surgery or liver 
transplantation. These parameters will be evaluated separately and together at weeks 24,
48, and 72 

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Change in growth from baseline to Weeks 24, 48, and 72 after initiation of A4250
treatment, defined as the linear growth deficit (height/length for age, weight for age, mid- 
arm circumference, and body mass index [BMI]) compared to the standard growth curve
(Z-score, standard deviation [SD] from P50) 
Change in AST to platelet ratio index (APRI) score and Fib-4 score from baseline to Week 
72
Change in pediatric end-stage liver disease (PELD)/model for end-stage liver disease 
(MELD) score from baseline to Week 72
Change in use of antipruritic medication at Weeks 24, 48, and 72
9.1.3
Exploratory Efficacy Endpoints
All Exploratory Endpoints will be evaluated at Weeks 24, 48, and 72 unless otherwise noted. 
Baseline is calculated prior to initiation of A4250 treatment. Exploratory endpoints include:
Change in serum ALT, GGT, and total bilirubin concentration from baseline to Week 72
Proportion of individual assessments meeting the definition of a positive pruritus
assessment at the patient level over the 72-week Treatment Period. A positive pruritus 
assessment includes an itch score 
-point drop from baseline based on
the Albireo PRO instrument; 
instrument
Change from baseline over the 72-week treatment period in sleep parameters measured
with the Albireo PRO and ObsRO instruments
Change from baseline in INR, albumin, liver enzymes, leukocytes, and platelets
Change from baseline measures of bile acid synthesis (autotaxin, p-C4)
Assessment of Global Symptom Relief at Weeks 4, 12, 24, 48, and 72 as measured by 
patient, caregiver, and clinician PGIC items
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 
24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 in patient-reported and 
observer-reported night time itching and scratching severity scores, respectively
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 
24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 in patient-reported and 
observer-reported morning time itching and scratching severity scores, respectively
Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 
24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 in pooled pruritus
score including observer-reported scratching for patients <8 years of age and patient- 
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Change from baseline by each 4-week interval between Visit 1/Screening and Visit 5/Week 
24, then by each visit between Visit 5/Week 24 to Visit 12/Week 76 in additional patient- 
reported and observer-reported sleep parameters (e.g., tiredness, number of awakenings) 
Change from baseline in PedsQL questionnaire
Change from baseline in stage of liver fibrosis as assessed by Fibroscan® (where available)
Change from baseline in stage of liver fibrosis as assessed by post-treatment biopsy (when 
available)
9.2
Efficacy Assessments
9.2.1
Serum Bile Acids
Blood samples for analysis of fasting serum bile acids will be drawn at all study visits from
Visit 1 (Visit S-1 for Cohort 2) through Visit 12. Fasting serum bile acids will also be drawn 
at all visits during the optional extension period. Patients will fast (only water intake is 
permissible) for at least 4 hours prior to the collection of samples for serum bile acids. 
Exceptions can be made for infants, less than 12 months of age, if unable to fast for the full 4 
hours. For any visit at which a bile acid sample result is unreportable, an additional 
unscheduled visit for a repeat sample collection may be scheduled. Samples will be handled 
and transported to a central laboratory per instructions in the laboratory manual. 
9.2.2
Itching and Sleep Score
Itching, observed scratching, and sleep disturbance will be assessed twice each day via eDiary. 
Patient/caregivers will be instructed to fill in the eDiary every morning and evening for the first 
24 weeks and the last 21 days before all the remaining visits to the clinic. There will be no 
interruption between Visits 11 and 12. Patients participating in the optional extension period 
will stop eDiary entries at Visit 11. Patients and/or caregivers will be instructed to complete
the eDiary in the morning after the patient wakes and in the evening just before the patient goes 
to sleep. 
The eDiary includes Albireo ObsRO and PRO items. Patients <8 years of age will not be asked 
to complete the Albireo PRO items; only the Albireo ObsRO will be completed by caregivers
items and the caregiver will complete the Albireo ObsRO items. The Albireo PRO items assess 
severity of itch, aspects of sleep disturbance (morning diary only), and tiredness. For patients 
8 to 12 years of age, the caregiver will read the Albireo PRO items along with the child and 
record the child’s response. A guide will be provided to the caregivers that provides 
standardized explanations of the Albireo PRO items, in case the patient is confused or requires 
clarification about the meaning of a question. The Albireo ObsRO items assess severity of 
observed scratching, aspects of observed sleep disturbance (morning diary only), and observed 
signs of tiredness (evening diary only).  The Albireo ObsRO and PRO scratching and itch

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severity items use 0 to 4 response scales, where each response is distinguished by a unique 
facial expression, verbal anchor, number, and color code (Appendix 2). 
A daily score AM and PM for the Albireo ObsRO scratching item will be averaged from the 
2 ratings for each day. A daily score will be considered missing if both of the daily
assessments are missing. A weekly score will be calculated by averaging the daily scratching 
scores. A weekly score will be considered missing if 4 out of 7 days a week of data are 
missing. For AM and PM baseline, a 14-day daily score of AM and PM prior to the first dose 
of study medication will be averaged as the baseline score. 
For AM baseline, a 14-day AM score prior to the first dose of study medication will be 
averaged as the baseline AM score. The same approach will be used for PM baseline and to 
calculate a patient-reported itch severity score.
9.2.3
Growth
Growth (height and weight) will be measured by the standardized assessments outlined in the 
US FDA guidance document, Orally Inhaled and Intranasal Corticosteroids: Evaluation of the 
Effects on Growth in Children (March 2007). Height and length (velocity) will be measured 
using a certified stadiometer and weight (Z-score) using a certified weight scale.
Mid-arm circumference (3 repeat measurements) will be collected at the study site.
Study sites will be trained on using a standardized approach when measuring height with a 
stadiometer and additional detailed instructions will be provided in study documents. 
BMI will be calculated by weight (kg) / height (m)2. Change will be defined as linear growth 
deficit (weight and BMI for age) compared to a standard growth curve. 
9.2.4
Biomarker Samples
Blood samples for p-C4 and autotaxin will be drawn at Visits 1, 2, 5, 8, and 11 (p-C4 and 
autotaxin will only be drawn for patients with body weight >10 kg). Samples will be treated 
and transported to a central laboratory per instructions in the laboratory manual. 
9.2.5
Change of Antipruritic Medication
Any change of antipruritic medication must be noted in the eCRF.
9.2.6
Quality of Life Questionnaire (PedsQL)
Caregivers and, if applicable, patients will be asked to fill out a QoL questionnaire (PedsQL) 
at Visits 1, 5, 8, 11 and at all visits of the optional extension period. Details of the questions 
included on the questionnaire can be found in Appendix 4.
9.2.7
PELD/MELD Score
The PELD score will be calculated for children up to 12 years of age. For patients 13 years or 
older, the MELD score will be calculated.

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PELD Score = 4.80 * ln(total bilirubin) + 18.57 * ln(INR) - 6.87 * ln(albumin) + 4.36 (if patient
<1 year: scores for patients listed for liver transplantation before the patient’s first birthday 
continue to include the value assigned for age (<1 year) until the patient reaches the age of 24 
months) + 6.67 (if patient has growth failure [<-2 SD])
Laboratory values less than 1.0 will be set to 1.0 for the calculation of the PELD score. 
MELD Score = 9.57 * ln(creatinine) + 3.78 * ln(total bilirubin) + 11.2 * ln(INR) + 6.43 
Laboratory values less than 1.0 will be set to 1.0 and serum creatinine values greater than
4.0 mg/dL (equivalent to 353.6 µmol/L) will be set to 4.0 for calculation of the MELD score.
If a patient goes from 11 years of age to 12 between the beginning and end of study, both PELD 
and MELD scores will be calculated at the first visit after the 12th birthday and move to MELD 
score. The results should be displayed in one summary table. 
9.2.8
Fibroscan®
Where available, Fibroscan® will be performed as per institution standard practice at Visits 1, 
5, 8, and 11. 
9.2.9
Markers of Fibrosis
APRI score and Fib-4 score will be calculated at Visits 1, 3, 5, 8, and 11.
APRI = [(AST in U/L) / (AST upper limit of normal [ULN] in U/L)] x 100 / (Platelets in 109/L) 
Fibrosis 4 Score = (Age*AST in U/L) / (Platelets in 109/L *  (ALT in U/L))
9.2.10
Liver Biopsy
If a liver biopsy is performed according to the local regulations or standard of care at any time 
during A4250-008, the biopsy results should be recorded in the eCRF. If the patient has liver 
biopsy results collected in study A4250-005 or prior to Week 24 in study A4250-008, the
patient will be asked to consent to a follow up liver biopsy, if allowed per local regulations, at 
Visit 11 unless 2 prior liver biopsy results have been collected with at least 1 year between 
biopsies. Liver biopsies will not be performed in Spain. 
9.2.11
Global Impression of Change and Global Impression of Symptom Measures
Patients, caregivers, and clinicians will complete the PGIC and the PGIS measures at Visits 1,
2, 3, 5, 8, 11, and at all visits of the optional extension period (Appendix 3). 
The PGIC items assess change in itch (patient version), scratching (caregiver and clinician 
versions), and sleep (all versions) since starting the study drug. The PGIS items assess itch 
(patient version), scratching (caregiver and clinician versions), and sleep (all versions) in the 
past week. Caregivers and clinicians will complete the PGIC and PGIS for all patients; those 
years of age will complete the patient version.

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10
ASSESSMENT OF SAFETY
The timing and frequency of safety assessments are described in Section 7.1.2 and 
Section 7.1.3.
The primary safety analysis for this study will include the incidence of total treatment-emergent 
adverse events (TEAE) and TEAEs categorized by causality, severity, and seriousness 
assessments.
Trends in safety will also be evaluated for the following assessments:
Physical examinations
Concomitant medications 
Vital signs
Laboratory test results (including clinical chemistry, hematology, urinalysis, AFP, vitamins 
A, E, and 25-hydroxy vitamin D, and INR) 
Abdominal ultrasound
Discontinuations due to AEs
10.1
Adverse Events
10.1.1
Definitions and Investigator Assessments
An AE is defined as any untoward medical occurrence in an enrolled patient regardless of
causal relationship with study drug. An AE can therefore be any clinically significant 
unfavorable and unintended sign, symptom, or disease that occurs once a patient is enrolled
(ICF is signed) in the study until the patient is discharged from the study, whether or not related 
to the study drug. 
10.1.1.1
Clinical Significance
Clinical significance is defined as any abnormal finding that results in further clinical 
investigation(s), treatment(s), or the diagnosis of new condition. Patient-reported events and 
protocol-mandated laboratory values, vital signs, and physical examination findings can be 
considered clinically significant (i.e., an AE) if there is a deterioration as compared to baseline. 
Examples of clinically significant worsening from baseline could include, but is not limited to, 
events causing withdrawal from the study and events requiring medical intervention outside of 
the study causing apparent clinical manifestations, or judged relevant by the investigator.
10.1.1.2
Serious Adverse Events
Serious criteria are applied by the investigator to each AE as specifically defined below. These 
criteria are used to determine whether an AE is serious or non-serious. The assessment is made 
independently of severity assessment (Section 10.1.1.3). For example, the development of a 

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severe rash that occurs after signing of informed consent may not meet serious criteria as 
defined below and therefore would be considered a severe, non-serious AE.
Any AE that meets any 1 of the following 6 criteria is considered an SAE: 
The outcome of the AE is death
The AE is immediately life-threatening. Life-threatening means that the patient is, in the 
opinion of the investigator, at immediate risk of death from the reaction as it occurred. This 
does not include an AE that, if more severe, might have caused death
The AE results in persistent or significant disability/incapacity. Disability means a 
substantial disruption of a person's ability to conduct normal life functions
The AE requires or prolongs hospitalization
The AE results in a congenital anomaly/birth defect
The AE is an important medical event. Important medical events may meet serious 
criteria should the investigator assess that they may significantly jeopardize the patient, 
represent a significant hazard, or requires medical/surgical intervention to prevent one of
the outcomes listed above. Examples of potential SAEs based on this criterium include, 
but are not limited to, allergic bronchospasm requiring intensive treatment in an emergency 
room or at home, blood dyscrasias or convulsions even if they do not result in inpatient 
hospitalization, or the development of drug dependency and drug abuse. 
10.1.1.3
Severity Assessment
Severity assessments are based on the intensity of the event in relation to expectation. The 
investigator will assess the intensity of AEs based on the following definitions: 
Mild (awareness of sign or symptom, but easily tolerated)
Moderate (discomfort sufficient to cause interference with normal activities)
 
Severe (incapacitating, with inability to perform normal activities) 
Severity is a measure of intensity where seriousness is defined by the criteria outlined in
Section 10.1.1.2. An AE of severe intensity need not necessarily be considered serious. For 
example, nausea that persists for several hours may be considered severe nausea, but not meet 
serious criteria, and therefore would be assessed as a severe AE but not an SAE.
10.1.1.4
Causality Assessment
The investigator determines the causality of all AEs to the study drug using medical judgment 
and considering all relevant factors such as (but not limited to) the underlying study indication, 
coexisting disease, concomitant medication, relevant history, pattern of the AE, temporal 
relationship to the study drug, and de-challenge or re-challenge. The causality assessment of
the AE/SAE is to be made as follows.

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Related to study drug (possibly, probably, or definitely related)
Based on medical judgment, there is at least a reasonable possibility that the study drug caused 
the event; one or more of the following criteria apply:
The event follows a reasonable temporal sequence from administration of study drug
The event could not be reasonably attributed to the known characteristics of the patient's 
clinical state, environmental or toxic factors, or other modes of therapy administered to the 
patient
The event follows a known pattern of response to study drug
The event disappears or decreases on cessation or reduction in dose of the study drug. (It 
should be noted that in some situations an AE will not disappear or decrease in intensity 
upon discontinuation of study drug despite other clear indications of relatedness) 
The event reappears or worsens when the study drug is re-administered
Unrelated to study drug (unlikely or unrelated)
Based on medical judgment there is no reasonable possibility that the study drug caused the 
event; one or more of the following criteria apply: 
The event does not follow a reasonable temporal sequence from administration of study
drug
The event could be reasonably attributed to the known characteristics of the patient's
clinical state, concurrent illness, environment or toxic factors, or other modes of therapy 
administered to the patient
The event does not follow a known pattern of response to study drug
The event does not disappear or decrease on cessation or reduction in dose of the study
drug, and it does not reappear or worsen when the study drug is re-administered
10.1.2
Recording of Adverse Events
It is the investigator’s responsibility to assess whether each untoward event is a clinically 
significant worsening from baseline, thereby considered an AE. For all AEs, the severity, 
seriousness, and causality to study drug for each AE as outlined in Section 10.1.1 will be 
assessed and recorded in the eCRF.
All serious and non-serious AEs are collected once the caregiver/patient has signed the ICF 
and until the post-treatment follow-up (Visit 12), 28 days after the last dose of study drug. 
Collection of all serious and non-serious AEs will continue for the optional extension period. 
Any AEs or SAEs that are unresolved at the patient’s last AE assessment in the study are 
followed up by the investigator until resolution or stabilization up to the database lock and

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recorded in the eCRF. Albireo retains the right to request additional information for any patient 
with ongoing AE(s) or SAE(s) at the end of the study. 
TEAEs that are ongoing at time of discontinuation will be followed up until week 72 by 
telephone calls every 3 months. No new AEs will be recorded after the patient has permanently 
discontinued study drug. 
TEAEs are defined as any AE that occurs after dosing (Day 1), including new AEs or the 
worsening of an event after the first dose.
If there is a clinically significant deterioration of a laboratory value/vital sign or other routine 
study assessment that is associated with a diagnosis, the clinical diagnosis will be reported as
an AE and the associated signs and symptoms will be considered additional information unless 
the sign or symptom is more severe than expected given the diagnosis. For example, if an 
investigator diagnoses a study patient with hepatitis during the study period, hepatitis would 
be considered the AE and the concomitant signs and symptoms of abdominal pain, vomiting, 
and elevated ALT and AST would not be reported separately unless, in the opinion of the 
investigator, one of these signs or symptoms is more severe than expected and therefore a 
separate AE assessment is indicated.
10.1.3
Recording and Reporting of Serious Adverse Events
Every SAE (regardless of severity and causality) that occurs once the caregiver/patient has 
signed the ICF and until the post-treatment follow-up (Visit 12), and 28 days after the final 
dose of study drug, should immediately and not later than within 24 hours of knowledge of the 
event, be reported by the investigator or delegate in the SAE Report Form. 
Report of a SAE must include at least the following information:
Patient identification information (study number, site number, initials, and date of birth [as 
per local country requirements for data protection]) 
The last study drug administration date
The  diagnosis  of  the  event  with  the  description  (or  a  brief  description  of 
signs/symptoms/clinical course if the diagnosis is not available) and the date of onset
The action used to treat the event (i.e., treatment medications, temporary discontinuation) 
The reason(s) for considering the event serious
The relationship of the event to the study drug or to the study procedure (e.g., the 
investigator's assessment of causality)
A brief narrative of the SAE
Follow-up reports including all new information obtained of the subsequent course of the SAE 
must be prepared and the information collected in the SAE Report Form submitted to ICON

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DRUG SAFETY (Pharmacovigilance and Safety Services Department) by e-mail within 
24 hours of knowledge of the event. 
The pharmacovigilance manager (PVM) may contact the investigator to obtain further 
information on a reported SAE. The investigator/investigative staff must respond to any 
request for follow-up information or answers to questions regarding the SAE within the same 
timelines as for initial reports. 
The PVM reports the occurrence of the SAE and follow-up to the Albireo Medical Monitor for 
medical assessment of the case. 
Should an outcome of death occur within the study period or within 28 days after the last 
administration of study drug, an SAE Report Form should be completed including the main 
and contributory causes of death. 
All SAE reports must be e-mailed to the following e-mail address within 24 hours: 
ICON DRUG SAFETY (Pharmacovigilance and Safety Services Department) 
E-mail: 
 
If email is unavailable, SAEs may be transmitted via fax to the following number: 
Fax No.: 
 
In a study-related medical emergency situation, when the assigned Medical Monitors for the 
study cannot be reached by a caller, an on-call physician can be reached 24 hours per day, 
7 days per week, via the ICON call center. The following number is a chargeable telephone 
number allowing a global reach from both landlines and mobile phones and the internet page 
indicated below contains a list of country-specific toll-free telephone numbers. It should be 
noted that not all countries globally have access to toll-free numbers as indicated on the 
“24/7 Medical Help desk” index. Countries without toll-free numbers need to dial the 
chargeable number as indicated below. Furthermore, toll-free numbers might not be available 
from mobile phones. 
On Call Telephone No.: 
 
https://icophone.iconplc.com 
10.1.4 
Reporting of Suspected Unexpected Serious Adverse Reactions 
Suspected unexpected serious adverse reaction (SUSAR) is an SAE that occurs in a patient, 
the nature or severity of which is not expected per the applicable product information (e.g., the 
IB for an unauthorized investigational product or summary of product characteristics for an 
authorized product). 
Reporting and tracking of SUSARs will be in accordance with all applicable competent 
authority regulations. The Ethics Committees and all investigators involved in this study will 
be informed according to national and international requirements. 
PPD
PPD
PPD

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10.2 
Laboratory Values/Vital Signs/Physical Examinations and Other Safety 
Assessments 
10.2.1 
Laboratory Assessments 
At the clinic visits indicated in Table 1, samples will be drawn for clinical chemistry, 
hematology, and urinalysis analyses. The parameters assessed are presented in Table 4. 
Blood for AFP will be drawn at Visits 1, 5, 8, and 11. Fat-soluble vitamin levels including 
vitamins A and E, and 25-hydroxy vitamin D will be assessed at Visits 1, 3, 4, 6, 7, 9, 10, and 
all optional extension period visits and INR (surrogate for vitamin K) will be assessed at Visits 
S-2 (Cohort 2 only), 2, 3, 4, 6, 7, 9, 10, and 12, and all optional extension period visits. Patients 
will fast (water intake only is permissible) for at least 4 hours prior to the collection of samples 
for vitamin A. Exceptions can be made for infants, <12 months of age, if unable to fast for the 
full 4 hours. If a patient has any vitamin level(s) that are outside of the reference range, vitamin 
supplementation adjustments may be required. Target ranges and supplementation strategy 
guidelines can be found in Appendix 5. 
A serum pregnancy test will be performed at Visits S-1 (Cohort 2) and Visit 1 (Cohort 1), and 
a urine pregnancy test will be collected at all other visits, including the optional extension 
period visits, for girls who have reached menarche. If a urine pregnancy test is positive, a 
serum pregnancy test should be performed to confirm the pregnancy. Study drug 
administration will be held pending the confirmatory results. If the serum pregnancy test is 
negative, the patient can resume dosing. If the serum pregnancy test is positive, the patient 
should be discontinued (see Section 10.2.9). 
All samples will be processed and transported to a laboratory per instructions in the laboratory 
manual. 
The observed values will be recorded and assessed as “normal” or “abnormal not clinically 
significant” or “abnormal clinically significant”. 
For hepatic adverse events and/or hepatic decompensation, a PK sample should be collected as 
close to the onset of the event as possible (PK samples are not required during the screening 
period). 
Additional safety blood samples may be needed due to follow-up of an abnormal value or 
analysis failure. The blood samples collected for safety laboratory analysis will be destroyed 
after the analyses have been completed. 

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Table 4 
Routine Laboratory Parameters
Clinical Chemistry
Hematology
Urinalysis
Albumin*
Hematocrit
Blood
ALT*
Hemoglobin
Glucose
Alkaline phosphatase*
Platelet count
Ketones
AST*
Red blood cell count
Leukocytes
Bilirubin – total and 
conjugated*
Calcium 
Chloride
White blood cell count and 
differential (neutrophils, 
eosinophils, basophils, 
lymphocytes, and monocytes)
Nitrites 
pH 
Protein
Creatinine
Creatine kinase
GGT
Potassium
Sodium
* Clinical chemistry for 
optional extension period
10.2.2
Individual Patient Safety Monitoring
10.2.2.1
Liver Monitoring
Strategies to monitor markers of liver disease throughout the study are outlined below where
the ULN will be based on central laboratory reference values for age and gender.
For abnormalities classified as hepatic adverse events and/or hepatic decompensation, a PK 
sample should be collected as close to the onset of the event as possible (PK samples are not 
required during the screening period).
If isolated transaminase elevations are observed, defined as:
1. Normal bilirubin AND absence of clinical hepatitis symptoms AND
whichever comes first
U/L, whichever comes first
Then:
a) Repeat liver profile (AST, ALT, bilirubin, and prothrombin time [PT] or INR) within 
2 to 3 days 
b) Evaluate creatine phosphokinase (CPK) and lactate dehydrogenase (LDH)
c) As needed (for example, persistent ALT/total bilirubin elevation or worsening of liver 
function), consider evaluation for alternative etiologies 

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Monitor the patient using close observation found in Section 10.2.2.2.
If any ONE of the following criteria are met:
1.
 
 or absolute threshold increase of +300 U/L,
whichever comes first) AND bilirubin increases to such where total bilirubin > 2 × ULN if 
total bilirubin was within normal range at baseline
2. Transaminase elevations alone (ALT or AST >5 × ULN for patients that were normal at 
baseline) or absolute threshold of +300 U/L (for patients starting with transaminases above 
ULN at baseline) in presence of normal LDH and CPK
3. Total bilirubin increased, unrelated to hemolysis
(elevated reticulocyte count) or
established genetic diseases, such as Gilbert’s syndrome
a)
Doubling if total bilirubin was <3 mg/dL (equivalent to 51.3 µmol/L) at baseline and 
total bilirubin is greater than 2 x ULN 
b)
OR Increase by >3 mg/dL 
(equivalent to 51.3 µmol/L) at baseline
4. INR increase refractory to vitamin K administration
a)
Increase by >1.5 if INR was normal at baseline
b)
OR Increase by >0.4 if INR was abnormal at baseline
5. Any increase in total bilirubin and transaminases if accompanied by EITHER a symptom 
of clinical hepatitis (e.g., vomiting, nausea, right upper quadrant pain) OR immunological 
reaction (rash or >5% eosinophilia) 
Then:
a)
Interrupt study medication
b)
Initiate drug-induced liver injury work-up for alternative etiologies
c)
Repeat liver profile (AST, ALT, total bilirubin, direct bilirubin) and PT or INR within 
48 to 72 hours 
d)
Monitor the patient using close observation found in Section 10.2.2.2
e)
If a patient lives in a remote area, they may be tested locally and the results 
communicated to the investigator site promptly
10.2.2.2
Close Observation
Repeat liver enzyme and serum bilirubin tests two or three times weekly. Frequency 
of re-testing can decrease to once a week or less if abnormalities stabilize or the trial 
drug has been discontinued and the patient is asymptomatic 
Obtain a more detailed history of symptoms and prior or concurrent diseases

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Obtain a history of concomitant drug use (including non-prescription medications and 
herbal and dietary supplement preparations), alcohol use, recreational drug use, and 
special diets
Consider ruling out alternate etiology including acute viral hepatitis types A, B, C, D, 
and 
E; 
autoimmune 
or 
alcoholic 
hepatitis; 
non-alcoholic 
steatohepatitis; 
hypoxic/ischemic hepatopathy; and biliary tract disease 
Obtain a history of exposure to environmental chemical agents
Obtain additional tests to evaluate liver function, as appropriate (e.g., INR, direct 
bilirubin)
Consider gastroenterology or hepatology consultations
Follow subjects with potential drug-induced liver injury (DILI) until the laboratory, and 
new associated clinical abnormalities have normalized or returned to baseline 
(enrollment) values or have stabilized (defined as laboratory values being stable for 
3 months). Continue to work up for alternate etiologies for the abnormal liver disease 
as stated above until case has resolved. If imaging changes are found as part of the 
assessment for etiology, these should be continued to be followed until normalization 
or returned to baseline or until the investigator feels the changes have stabilized.
10.2.2.3
De-challenge/Re-challenge for Liver and Clinical Hepatitis Monitoring
1. Re-challenge is not recommended:
a) If a patient has had possible/probable drug-induced liver injury
b) If a decompensation event has occurred (i.e., variceal hemorrhage, ascites, hepatic 
encephalopathy, etc.). 
2. If the event is assessed as due to underlying cholestatic liver disease variability or another 
alternative etiology is identified AND liver tests returned to baseline, re-challenge may be 
considered after consultation with the sponsor Medical Monitor.
3. If the ALT/total bilirubin elevations are observed after re-challenge, then repeat
re-challenge is discouraged.
If a patient is permanently discontinued, monitoring should be continued as outlined in 
Section 10.2.2.8.
10.2.2.4
Diarrhea
Study drug should be discontinued if a patient develops diarrhea with at least 1 of the following 
concomitant signs or symptoms: grossly bloody stools, vomiting, dehydration requiring
°C)
and/or the diarrhea persists for 7 or more days.
should be assessed using hemoccult cards. 

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Blood in stools or any other signs of bleeding should trigger clinical and laboratory assessment 
such as measurement of PT/aPTT, INR, platelets, etc. Any deficits should be corrected, as 
clinically indicated.
Cause of bleeding should be investigated, and an evaluation should be obtained. If there is a 
reduction in hemoglobin greater than 2 g/dL there should be a discussion with the Medical 
Monitor and the appropriate work up will be decided. Information needed for this discussion 
should include presence of any diarrhea, recent iron studies, any signs of gross bleeding and 
what organs are involved, recent and current complete blood count, INR, any changes in heart 
rate, blood pressure, weight, last results of imaging and endoscopy/ colonoscopy and recent 
infectious work up, if done. 
If gross blood in stool/bleeding is seen, an AE of blood in stool/bleeding should be reported.
Study drug will be reintroduced (re-challenge) when the symptoms have resolved. If the 
diarrhea re-occurs within 1 week after the re-challenge with no alternate etiology, the patient 
will be permanently discontinued and monitored as outlined in Section 10.2.2.8.
10.2.2.5
Fat-soluble Vitamin Deficiency
Queries related to TEAEs indicative of end-organ damage, i.e., impaired hepatic synthetic 
function presenting as e.g., bone fracture/rickets, GI or other organ bleeding/ecchymosis or
night blindness, will be issued when a patient presents with worsening of fat-soluble vitamin 
deficiency (see Section 10.2.1 for monitoring fat-soluble vitamin levels by laboratory 
assessments). Treatment should be discontinued in patients with evidence of end-organ damage 
due to fat-soluble vitamin deficiency.
10.2.2.6
Treatment-emergent Iron Deficiency Anemia
Events of iron deficiency anemia are identified as part of TEAE reporting and hematology 
assessments. Patients will be evaluated for fecal blood loss if they present with:
A decrease
 2 g/dL
A report of blood in stool; if so, a further diagnostic work up will be performed, 
following confirmation of blood in stool with hemoccult cards. 
Patients will be managed per institutional standard of care with iron supplementation.
10.2.2.7
Re-challenge after Discontinuation/Interruption of Study Drug
The DSMB will evaluate the safety data for patients who have discontinued study drug for an 
extended period on a case-by-case basis to determine whether re-challenge with A4250 is 
appropriate. The minimal duration of the discontinuation should be at least one to two weeks.
Patients that have discontinued for an extended period and allowed re-challenge by DSMB will 
use the last labs prior to restart as the new baseline for determining if DILI criteria are met.

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10.2.2.8 
Monitoring after Permanent Discontinuation of Study Drug Due to Safety 
Once study drug is permanently discontinued for liver, hepatitis, diarrhea, or other severe AE 
related to study drug, the patient will be monitored weekly until the laboratory and clinical 
parameters have normalized/stabilized. 
10.2.3 
Demographics/Medical and Surgical History (For Cohort 2 only) 
Demographic information per country regulations, along with medical and surgical history, 
will be obtained and recorded in the eCRF at Visit S-1. 
Medical and surgical history will be entered in the eCRF at Visit S-1. This includes date of 
diagnosis of PFIC, prior investigational medications for PFIC, historical (3 months prior to 
Screening, and up to 5 years prior to Screening for BRIC) hepatic biochemical parameters (e.g., 
AST, ALT, and total bilirubin), ongoing medication, any surgery performed, any other 
diagnosis, and historical biopsy data. 
For patients with BRIC, information on flares will be collected, including frequency, duration, 
and severity of flares within the last 6 months at a minimum, and within the last 5 years, if 
possible. A flare/cholestatic episode can be self-reported or clinically assessed based on 
medical history. Clinical signs and symptoms during a cholestatic episode/flare can include 
nausea, vomiting and pruritus followed by jaundice, fatigue, weight loss, malaise, steatorrhoa, 
night blindness. Increased bilirubin and alkaline phosphatase levels and increased INR can be 
observed. ALT, AST and GGT can be normal to mildly elevated. 
If a liver biopsy has been performed within 1 year prior to Screening, or during the study, the 
results will be recorded in the eCRF. 
10.2.4 
Clinical Genetic Testing (For Cohort 2 only) 
For previous confirmatory clinical genetic testing results for PFIC, including BRIC, Type 
performed prior to Screening Visit S-1, the confirmatory clinical genetic testing laboratory 
report will be verified to determine eligibility. 
If the historical clinical genetic result is equivocal, unavailable, or unobtainable, clinical 
genetic analysis will be performed to confirm pathologic biallelic variations of the ATP8B1, 
ABCB11 ABCB4, NR1H4, TJP2, DCDC2, CLDN1, and MYO5B genes and verified to 
determine eligibility. No other diagnostic genetic testing will be offered. 
10.2.5 
Physical Examination 
A physician or suitably trained qualified assistant will perform a complete physical 
examination, including a skin examination, at Visits S-1, 1, 3, 5, 8, and 11. 
A complete physical examination will include assessment of general appearance, eyes, ears, 
nose, throat, head/neck/thyroid, lymph nodes, cardiovascular, lungs/chest, abdomen, 
genitourinary, extremities, skin, musculoskeletal, neurologic, and other.  An abbreviated 

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physical examination will include general appearance, cardiovascular, abdomen, and other 
assessments based on patient status. 
Skin will be thoroughly examined and excoriations/scratch marks recorded. 
10.2.6 
Vital Signs 
Evaluation of vital signs will be performed at all visits. This includes blood pressure (systolic 
and diastolic), pulse, respiratory rate, temperature, height/length (using certified stadiometer), 
mid-arm circumference (3 repeat measures), and body weight (using a certified weight scale) 
at clinic visits. BMI will be calculated. 
10.2.7 
Abdominal ultrasound 
Ultrasound of the liver and spleen will be performed at Visits 1, 5, 8, and 11. Liver size, 
echogenicity, and presence of masses/nodules as well as spleen size will be recorded. If an 
ultrasound is performed as standard of care during the optional extension period, the data 
should be recorded in the electronic case report form (eCRF). 
10.2.8 
Overdose 
A4250 is minimally absorbed and has a very low systemic availability. Based on toxicology 
data, for study purposes any dose exceeding a total of >3 mg/kg body weight of A4250 taken 
as a single dose or as a cumulative dose within 24 hours is defined as an overdose. 
The no-adverse-effect dose level in the most sensitive species (defined as 20 mg/kg/day) in the 
rat 1 month toxicity study gives a human equivalent dose of approximately 194 mg/day in a 
60 kg person. This dose is approximately 10-fold higher than the maximum possible dose 
predicted in human studies (20 mg). 
The investigator/investigative staff should immediately, and not later than within 24 hours of 
knowledge, report an overdose in the SAE Report Form. In the event of an A4250 overdose, 
the patient should be monitored closely. 
10.2.9 
Pregnancy 
If a pregnancy is discovered in a female patient enrolled in the study before the end of dosing 
the patient will be immediately discontinued from the study and will attend the same visits as 
a prematurely withdrawn patient. If the pregnancy is discovered after the end of dosing the 
patient will continue in the study per protocol. If a pregnancy occurs in a male patient’s partner 
at any time during the study, the pregnancy should also be reported and followed. 
Pregnancy is not considered to be an AE. However, if the patient has been dosed with the study 
drug, the pregnancy must be reported on the Paper Pregnancy Notification Form immediately 
within 24 hours after recognition to Pharmacovigilance Manager and Pharmacovigilance and 
Safety Services Department (please refer to Section 10.1.3). Date of exposure and as far as 
possible, details of the period of gestation at the time of exposure must be given. 

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The pregnancy should be followed up to determine outcome, including spontaneous 
termination, details of birth, and presence of any birth defects, congenital anomalies or 
newborn or maternal complication. An infant who was exposed in-utero will be followed for 
up to 2 years after delivery. Individual cases with an abnormal outcome in association with 
the study drug should be reported on an expedited basis, i.e., reported rapidly to a competent 
authority. 

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11 
STATISTICAL EVALUATION 
11.1 
Sample Size and Power 
There is no formal hypothesis testing in this open label study. Sample size for Cohort 1 was 
determined in Study A4250-005. For Cohort 1, patients will be enrolled following completion 
or participation of 12 weeks of Study A4250-005. The expected proportion of patients with at 
least one event, i.e., surgical bile diversion or liver transplantation or death, in untreated 
patients is expected to be high enough to be able to detect an improvement after A4250 
treatment. For the other endpoints, mainly descriptive analyses will be performed. 
The proportion of patients with at least one event (i.e., surgical bile diversion or liver 
transplantation or death), that can be expected in a non-treated population depends on PFIC 
type and age distribution of the included patients. The expected proportion of patients with 
events will be calculated for the study population once each patient’s age and PFIC type are 
known, using the probability that a patient will get an event estimated from the reference 
population in the ongoing observational cohort study, NAtural Course and Prognosis of PFIC 
and Effect of Biliary Diversion (NAPPED). 
As an example, if the expected proportion with at least one event is estimated to be 30% in the 
study population, and then if the proportion of patients with at least one event during A4250 
long-term treatment are shown to be only 10% in the study, the power is approximately 89% 
to 96% (1-sided test, alpha=2.5%) for a confidence interval (CI) with upper boundary <30% 
based on a sample size of n=48 to 60. The sample size of 60 patients for Cohort 2 was estimated 
based on the availability of target patient population to evaluate the therapeutic benefit for those 
patients. 
11.2 
Statistical Methods 
11.2.1 
Statistical Analysis Sets 
Full Analysis Set 
The full analysis set (FAS) will consist of all patients who received at least 1 dose of study 
drug in Study A4250-008. The FAS will be the primary analysis set for all analyses unless 
otherwise specified. 
11.2.2 
Methods of Statistical Analyses 
11.2.2.1 
General Principles 
Descriptive statistics will mainly be used in this open-label extension study. Patients with BRIC 
will be presented separately in efficacy assessments. All statistical analyses will be performed 
using SAS version 9.3 or higher. 
The primary analysis will be performed after the last patient (from Cohort 1 or 2) completes 
the 72-week treatment period. Analyses during the extension period will consist of safety 

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summaries and other evaluations on an ongoing basis per the schedule of assessment for the 
extension period. 
Baseline 1 will be defined as the last value prior to treatment start in Study A4250-005 for 
Cohort 1 patients.
Baseline 2 will be defined as the last value prior to treatment start in Study A4250-008 for all 
patients. Baseline 2 will be used in all analyses unless otherwise specified.
Descriptive statistics will be summarized for Cohort 1, Cohort 2 excluding BRIC, Cohort 2 
BRIC, and combined Cohort 1 + Cohort 2 excluding BRIC. Within Cohort 1, the following 
subgroups will be presented: ‘A4250 40 µg/kg/day (005) to 120 µg/kg/day (008)’, ‘A4250 120
µg/kg/day (005) to 120 µg/kg/day (008)’, ‘A4250 40 µg/kg/day (005) and 120 µg/kg/day (005)
to 120 µg/kg/day (008)’, and ‘placebo (005) to 120 µg/kg/day (008)’.  Within Cohort 2 
excluding BRIC, 3 subgoups (‘40 µg/kg/day’, ‘40 µg/kg/day to 120 µg/kg/day’, and ‘120 
µg/kg/day’) will be presented. Cohort 1 Placebo to A4250 120 µg/kg/day will also be
combined with Cohort 2 excluding BRIC for presentations. 
11.2.2.2
Missing Data
Missing data will be reported descriptively. In general, imputations of missing observations 
will not be made. Any additional sensitivity analysis concerning missingness and details 
regarding handling of missing data will be described in the statistical analysis plan (SAP).
Continued collection of efficacy data for patients who discontinue treatment will be made as 
far as possible.
11.2.2.3
Demographic and Baseline Characteristics
For Cohort 1, descriptive summaries of demographics and other baseline characteristics 
(including medical and surgical history) will be presented overall using the FAS. For Cohort 2, 
descriptive summaries of demographics and other baseline characteristics will be presented 
overall for the full analysis set as well as by the underlying diagnostics subgroups. 
Prior medication will be summarized overall using the full analysis set.
11.2.2.4
Subject Disposition
The following will be summarized overall by Cohort:
Patients enrolled (who signed the informed consent)
Patients treated
Patients completing treatment
Patients discontinuing treatment and reason 
Patients completing the study
Patients withdrawing early (including withdrawal reason)

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Additionally, patients enrolled, included in the FAS will be summarized by region by Cohort.
11.2.2.5
Evaluation of Primary Efficacy Variables
The proportion of positive pruritus assessments at the patient level over the 72-week 
treatment period will be summarized. A positive pruritus assessment is defined as a 
-point drop from baseline on the Albireo ObsRO 
instrument. At each assessment, the AM score will be compared to the baseline AM average, 
and the PM score will be compared to the baseline PM average. Both AM and PM pruritus 
assessments will be included in the analysis of this endpoint. Baseline will be defined as the 
average score from 14 days prior to treatment start in Study A4250-008 for AM and PM, 
respectively.
Fasting serum bile acids baseline will be calculated as the average of the pre-dose value in 
Study A4250-008 (Visit 1) and the previous visit (Visit 8 in study A4250-005) for Cohort 1. 
Fasting serum bile acids baseline will be calculated as the average of Visit S-2 and the pre- 
dose Visit 1 values in Study A4250-008 for Cohort 2. The end value is the average of the 
values at Weeks 70 and 72 in study A4250-008. 
The change from baseline over the Treatment Period in serum bile acids will be analyzed 
mainly by using descriptive statistics. Change over time will also be displayed using 
graphical presentations (e.g., a spaghetti plot which illustrates the change in both Study 
A4250-005 and Study A4250-008 by treatment group in Study A4250-005). In addition, 
change from baseline 1 to end of treatment will be analyzed by using one-sample T-test or 
Wilcoxon signed-rank test as appropriate.
As an exploratory analysis of pruritus and serum bile acids, a comparison of treatment with 
A4250 120 µg/kg/day during the first 24 weeks of Study 008 vs placebo patients over the 24- 
week treatment period from Study 005 will be carried out. 
11.2.2.6
Evaluation of Secondary and Exploratory Efficacy Variables
All secondary and exploratory variables listed under Sections 9.1.2 and 9.1.3 will be analyzed 
descriptively for categorical and continuous data, as applicable. For continuous data, the
change from baseline will be analyzed in addition to the actual visit values. For categorical 
data, shift tables or frequency and percentages of patients will be presented as appropriate.
Change in growth (Z-score, SD from P50 standard growth curve) will be analyzed by using
one-sample T-test or Wilcoxon signed-rank test as appropriate.
Change in growth
(height/length for age, weight for age, BMI, and mid-arm circumference) will also be displayed 
using graphical presentations.
A 95% CI will be calculated for the proportion of patients experiencing surgical bile diversion 
or liver transplantation or death as well as for the proportion of patients experiencing surgical 
bile diversion or death or liver transplantation. The upper boundary will be compared to the

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expected proportion of events, using the event probability estimated from the untreated 
reference population in an ongoing observational cohort study. 
Time to first event, i.e., time to surgical bile diversion or liver transplantation or death, will be 
explored by descriptive statistics and Kaplan-Meier curves, which also will be used to make a 
comparison to the NAPPED population. The propensity score matched cohort analysis using 
inverse probability of treatment weights will be used to match the study patient population to
the reference population based on age group and PFIC type. 
11.2.2.7
Evaluation of Safety Variables
Safety data will be analyzed using descriptive statistics and summaries overall of SAEs, AEs, 
vital signs, clinical laboratory tests (hematology, clinical chemistry and urinalysis) and 
concomitant medication. Analyses will be performed using the full analysis set.
Summaries of AEs (coded according to the Medical Dictionary for Regulatory Activities 
(MedDRA) system organ class and MedDRA preferred term) will include: 
Overview of the incidence of TEAEs (TEAEs, Drug-related TEAEs, TEAEs leading to 
study discontinuation, and Treatment-emergent SAEs)
TEAEs by system organ class (SOC) and preferred term
 
Intensity of TEAEs by SOC and preferred term 
Drug-related TEAEs by SOC and preferred term
TEAEs leading to study discontinuation by SOC and preferred term 
Treatment-emergent SAEs by SOC and preferred term
Concomitant medication use during the Treatment Period will be summarized by Anatomical 
Therapeutic Chemical (ATC) class and World Health Organization (WHO) preferred name.
Summaries of vital signs will be presented. For each visit, the actual results and the change 
from baseline, and the number and percentage of patients with potentially clinically significant 
(PCS) values observed post-baseline will be presented.
Summaries of clinical safety laboratory data will be presented. For each visit, the actual result 
and the change from baseline, and the number and percentage of patients with PCS values 
observed post-baseline will be presented.
Data listings will be provided for each patient for all safety parameters.
11.2.2.8
Compliance and Exposure
Exposure will be analyzed by calculating the number of days with exposure to study drug. For 
Cohort 2 patients who dose escalate from 40 µg/kg/day to 120 µg/kg/day, exposure in each
dose and overall will be calculated. Results will be presented overall using the full analysis 
set.

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The percentage compliance will be described overall, and the number of patients with a 
A summary of patients who down-titrated from 120 µg/kg/day to 40 µg/kg/day during the study 
will be presented as well.
11.2.3
Interim Analysis
Analyses may be performed at select time points throughout the collection of patient data for 
regulatory requirements and sponsor decision making purposes. 
11.2.4
Data Safety Monitoring Board
A DSMB consisting of sponsor-independent clinical experts and sponsor-independent
statistical expert(s) will be established for Study A4250-005, and continue for this study until 
the last patient completes the 72-week treatment period. The DSMB will periodically 
(approximately on a quarterly basis) meet for the review of accumulating study data, including 
safety (AE and laboratory data), and liver values. 
The DSMB will make recommendations for the remaining part of the study (further details will 
be provided in the DSMB charter). The DSMB may recommend continuing with the study as 
planned or stopping the study early for safety reasons.
The DSMB will submit its 
recommendations in writing to Albireo Medical/ICON who are responsible for responding to
the recommendations of the DSMB and taking appropriate action. The investigators will only 
be informed by Albireo Medical/ICON if the study requires a protocol amendment or is
stopped. The DSMB may choose to make additional evaluations at any time if they feel this is 
warranted from a safety point of view. 
The DSMB will act according to its own written standard operating procedure described in a 
charter and will prepare written minutes of its meetings. The charter of the DSMB will be 
stored in the Trial Master File. The DSMB will maintain records of its meetings and these will 
become part of the study file when the study is complete.

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12 
DIRECT ACCESS TO SOURCE DATA/NOTES 
The investigator/institution shall provide direct access to source data/documents for 
study-related monitoring, audits, IEC/IRB review and regulatory inspection. 

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13 
QUALITY CONTROL AND QUALITY ASSURANCE 
13.1 
Conduct of the Study 
Albireo/ICON shall implement and maintain quality control and quality assurance procedures 
with written standard operating procedures to ensure that the study is conducted and data are 
generated, documented, and reported in compliance with the protocol, Good Clinical Practice 
(GCP) and applicable regulatory requirements. 
This study shall be conducted in accordance with the provisions of the Declaration of Helsinki 
(October 1996) and all revisions thereof, and in accordance with US FDA regulations (Code 
of Federal Regulations, Sections 312.50 and 312.56) and with International Council for 
Harmonisation (ICH) GCP (EMA/CHMP/ICH/135/1995), as applicable. 
The investigator may not deviate from the protocol without a formal protocol amendment 
having been established and approved by the competent authority, as applicable, and IEC/IRB 
approval, except when necessary to eliminate immediate hazards to the patient or when the 
change(s) involve(s) only logistical or administrative aspects of the study. Any deviations may 
result in the patient having to be withdrawn from the study and render that patient 
non-evaluable. 
13.2 
Study Monitoring 
Before study initiation, at a site initiation visit or at an investigator’s meeting, an Albireo 
representative or designee will review the protocol and eCRF with the investigators and the 
investigative staff. During the study, the clinical monitor (clinical research associate [CRA]) 
will visit the site regularly to check the completeness of patient records, the accuracy of entries 
on the eCRFs, the adherence to the protocol and to GCP, the progress of enrollment, and to 
ensure that study drug is being stored, dispensed, and accounted for according to specifications. 
The investigator must ensure that eCRFs are completed within a timely period of the patient 
visits, as per individual site agreements, and must allow the CRA and Albireo representative 
or designee periodic access to patient records and all study-related materials, including relevant 
hospital or clinical records, to confirm their consistency with the eCRF entries. No information 
in these records about the identity of the patients will leave the study center. Albireo 
monitoring standards require full verification for the presence of the signed ICF, adherence to 
the inclusion/exclusion criteria, documentation of SAEs, and recording of primary efficacy and 
safety variables. The CRA will review source data compared with the eCRFs and will verify 
source data according to the study-specific monitoring plan. The design of the study, the 
frequency of patient visits, and the site enrollment rate will determine the frequency of 
monitoring visits. Upon study completion, the CRA will visit the site to conduct a study 
termination visit, which will include collection of any outstanding documentation. 

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Remote monitoring practices may be employed in accordance with the country/institution 
specific guidelines in circumstances where an on-site monitoring visit is not feasible (i.e., 
COVID-19). 
It is recommended that the investigator/investigative staff log into the eCRF system every 
working day or at minimum twice weekly in order to provide a prompt response to queries. 
The investigator/investigative staff should respond to queries and make any relevant changes 
to the study data within 3 working days. 

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14 
ETHICS 
14.1 
Independent Ethics Committee/Institutional Review Board 
Prior to the start of the study, the investigator is responsible for ensuring that the protocol and 
informed consent form (ICF) have been reviewed and approved by the applicable IEC/IRB and 
competent authority. The IEC/IRB shall be appropriately constituted and perform its functions 
in accordance with US FDA, ICH GCP and/or local requirements, as applicable. 
The IEC/IRB and regulatory authority (competent authority), as applicable, shall approve all 
protocol amendments (except for logistical or administrative changes), written informed 
consent 
documents 
and 
document 
updates, 
patient 
recruitment 
procedures 
(e.g., 
advertisements), written information to be provided to the patients, IB, available safety 
information, information about payment and compensation available to patients and caregivers, 
the investigator's curriculum vitae and/or other evidence of qualifications and any other 
documents requested by the IEC/IRB or competent authority. 
14.2 
Written Informed Consents and Assents 
The investigator (physician) or investigative staff, as according to local regulation, will explain 
to each patient (or legally authorized representative) the nature of the study, its purpose, the 
procedures involved, the expected duration, alternative treatment, the potential risks and 
benefits involved, and any discomfort that may occur. Each caregiver/patient will be informed 
that participation in the study is voluntary and that he/she or their child may withdraw from the 
study at any time and that withdrawal of consent will not affect his/her subsequent medical 
treatment or relationship with the treating physician. 
Caregivers/patients will be informed that they/their children may experience side-effects or be 
at risk for symptoms, illnesses, or complications that cannot be foreseen by Albireo. As with 
other medications, people treated with A4250 may be at risk of developing allergic reactions 
or anaphylaxis. Caregivers/patients will be advised that study procedures include regular blood 
sampling for measurement of safety parameters and biological markers and that some minor 
risks are associated with these procedures. 
This informed consent should be given by means of a signed ICF, written in non-technical 
language in accordance with applicable GCP, the Declaration of Helsinki, and regulatory 
authorities. The caregiver(s)/patient should read and consider the statements before signing 
and dating them and should be given a copy of each signed document. If written consent is not 
possible, oral consent can be obtained if witnessed and followed by a signed statement from 
one or more persons not involved in the study, indicating why the patient was unable to sign 
the form. No patient can enter the study before his/her or caregiver(s), as required by country 
regulation, informed consent has been obtained. 
The ICF must be submitted by the investigator/investigative staff with the protocol to the 
applicable IEC/IRB for review and approval. Albireo will supply an ICF which complies with 

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regulatory requirements and country laws and is considered appropriate for the study. Any 
changes to the ICF suggested by the investigator must be agreed to by Albireo before 
submission to the IEC and a copy of the approved version must be provided to the clinical 
monitor after IEC approval. 

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15 
DATA HANDLING AND RECORD KEEPING 
15.1 
Case Report Forms/Source Data Handling 
The investigator shall be provided with standardized eCRFs and shall ensure that all data from 
patient visits are promptly entered into the eCRFs in accordance with the specific instructions 
given. The investigator must sign each completed eCRF, verifying the accuracy and integrity 
of the data recorded. 
A list of the normal ranges for all laboratory tests to be undertaken forms part of the 
documentation to be collated prior to study start. As a central laboratory has been selected to 
conduct any or all tests, it is essential that all samples be analyzed at the central laboratory. 
The investigator must maintain source documents such as laboratory reports, consultation 
reports, and complete medical history and physical examination reports. 
As no ethnicity data can be collected in the source document for study sites in France, the eCRF 
will be the Source Document for “origines ethniques”. 
15.2 
Retention of Essential Documents 
Essential documents, as defined by ICH GCP, include: the signed protocol and any 
amendment(s); copies of the completed eCRFs (for site archiving, compact discs of eCRF data 
for participating patients will be provided); signed ICFs; hospital records and other source 
documents; IEC/IRB approvals, including the associated documents, and all related 
correspondence; drug accountability records; study correspondence; and a list of patients’ 
names and addresses. 
The investigator/investigative staff must retain copies of these essential documents for the 
minimal period specified by ICH GCP and/or by applicable regulatory requirements 
(whichever is longer). The investigator/investigative staff will inform Albireo of the location 
where the essential documents are stored and must contact Albireo for approval before 
disposing of any essential documents. The investigator/investigative staff should take 
measures to prevent accidental or premature destruction of these documents. 

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16 
FINANCING AND INSURANCE 
Financing and insurance are addressed in a separate agreement. 

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17 
PUBLICATION POLICY 
Albireo will retain the ownership of all data. When the study is complete, Albireo shall arrange 
the analysis, tabulation of data and preparation of a clinical study report. Albireo may also use 
the data for publication, presentation at scientific meetings and submission to regulatory 
authorities. All proposed publications based on this study must be subject to the sponsor's 
approval requirements. 

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18
REFERENCE LIST
1. A4250 Investigator’s Brochure.
2. Alissa FT, Jaffe R, Shneider BL. Update on progressive familial intrahepatic cholestasis. J 
Pediatr Gastroenterol Nutr. 2008;46(3):241-52. 
3. Bull LN, Thompson RJ. Progressive Familial Intrahepatic Cholestasis. Clin Liver Dis. 2018 
Nov;22(4):657-669.
4. Davit-Spraul A, Gonzales E, Baussan C, et al. Progressive familial intrahepatic cholestasis. 
Orphanet J Rare Disease 2009;4:112. 
5. Gomez-Ospina N, Potter CJ, Xiao R, et al. Mutations in the nuclear bile acid receptor FXR 
cause progressive familial intrahepatic cholestasis. Nat Commun. 2016 Feb 18;7:10713. 
6. Hofmann AF. The enterohepatic circulation of bile acids in mammals: form and functions. 
Front Biosci (Landmark Ed). 2009 Jan 1;14:258498. 
7. Hori T, Justin H, Nguyen JH and Uemoto S. Progressive familial intrahepatic cholestasis. 
Hepatobiliary pancreat Dis Int. 2010; 9(6):5708. 
8. Jacquemin E. Progressive familial intrahepatic cholestasis. Genetic basis and treatment.
Clin Liver Dis. 2000 Nov;4(4):75363. 
9. Miethke AG, Zhang W, Simmons J, et al. Pharmacological inhibition of ASBT changes 
bile composition and blocks progression of sclerosing cholangitis in mdr2 knockout mice. 
Hepatology. 2016 February; 63(2):512–23.
10. Murray CS, Rees JL. Are subjective accounts of itch to be relied on? The lack of relation 
between visual analogue itch scores and actigraphic measures of scratch. Acta Derm 
Venereol. 2011;91(1):1823. 
11. Pawlikowska L, Strautnieks S, Jankowska I. et al. Differences in presentation and 
progression between severe FIC1 and BSEP deficiencies, J Hepatol. 2010; 53(1):1708. 
12. Shneider BL, Magee JC, Bezerra JA, et al. Efficacy of fat-soluble vitamin supplementation 
in infants with biliary atresia. Pediatrics, 2012;130(3):e607-14. 
13. Stapelbroek JM, van Erpecum KJ, Klomp LW, Houwen RH. Liver disease associated with 
canalicular transport defects: current and future therapies. J Hepatol. 2010 Feb;52(2):258- 
71.
14.
Mechanisms  to  Clinical  Implications.  Can  J  Gastroenterol  Hepatol.  2018  Jul 
26;2018:2313675.
15. Strubbe B, Geerts A, Van Vlierberghe H, Colle I. Progressive familial intrahepatic 
cholestasis and benign recurrent intrahepatic cholestasis: a review. Acta Gastroenterol 
Belg. 2012 Dec;75(4):405-10. 

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16. Suchy FJ. “Approach to the Infant With Cholestasis.” Liver Disease in Children. Ed. 
Frederick J. Suchy. New York: Cambridge University Press; 2007 179-189. Print. 
17. Venkat VL, Shneider BL, Magee JC, et al. Total Serum Bilirubin Predicts Fat-Soluble 
Vitamin Deficiency Better Than Serum Bile Acids in Infants with Biliary Atresia. J Pediatr 
Gastroenterol Nutr. 2014;59(6):702-7. 
18. Vitale G, Gitto S, Vukotic R, et al. Familial intrahepatic cholestasis: New and wide 
perspectives. Dig Liver Dis. 2019 Jul;51(7):922-33. 
19. Whitington PF, Whitington GL. Partial external diversion of bile for the treatment of 
intractable 
pruritus 
associated 
with 
intrahepatic 
cholestasis. 
Gastroenterology. 
1988;95(1):1306. 

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19 
APPENDICES 
Appendix 1 
Concomitant Medication Guidelines 

 
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Appendix 2 
Diary Questions including Albireo Patient-Reported 
Outcomes/Observer-Reported Outcome Instrument 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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Appendix 2: Diary Questions including Albireo Patient-Reported 
Outcomes/Observer-Reported Outcome Instrument 
Patient-Reported Outcome 
 
Morning Diary (to be completed shortly after waking each morning) 
Please answer the questions on the following screens. There are no right or wrong answers. Please 
think about the time since you went to bed last night (beginning when you started trying to fall 
asleep). 
1. How bad was your worst itching since you 
went to bed last night? 
 
2. How hard was it to fall asleep last night 
because of your itching? 
 
3. How hard was it to stay asleep last night 
because of your itching? 
 
4. Did you wake up last night because of 
itching? 
No / Yes 
5.  How tired do you feel this morning? 
 
 
 
Bedtime Diary (to be completed when going to bed each night) 
Please answer the questions on the following screens. There are no right or wrong answers. Please 
think about the time since you woke up this morning. 
1. How bad was your worst itching since you 
woke up this morning? 
 
2. How tired were you since you woke up this 
morning? 
 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 05, 18 March 2020 
 
 
 
Observer Reported Outcome 
 
Morning Diary (to be completed shortly after child wakes up each morning) 
Please answer the questions on the following screens. There are no right or wrong answers. Please 
think about the time since your child went to bed last night (beginning when your child started trying 
to fall asleep). As a reminder, when we use the term “scratching,” we would like you to think about all 
of the different types of scratching behaviors that you can see. 
1. How bad was your child’s worst scratching 
since he/she went to bed last night? 
 
2. Since your child went to bed last night, did 
you see blood due to scratching? 
No / Yes 
3. Did your child need a caregiver to help 
him/her fall asleep last night due to his/her 
itching? 
No / Yes 
4.  Did your child need a caregiver to soothe 
him/her at some time during the night last 
night due to his/her itching? 
No / Yes 
5.  Did your child need a caregiver to sleep 
with him/her at some time during the night 
last night due to his/her itching? 
No / Yes 
6.  How many times did you notice that your 
child woke up last night? 
0-99 
7. Did your child take any prescribed or over- 
the-counter medicines before going to bed 
last night that may have made him/her 
sleepy? 
No / Yes 
 
 
Bedtime Diary (to be completed when child is going to bed each night) 
Please answer the questions on the following screens. There are no right or wrong answers. Please 
think about the time since your child woke up this morning. As a reminder, when we use the term 
“scratching,” we would like you to think about all of the different types of scratching behaviors that 
you can see. 
1. How bad was your child’s worst scratching 
since he/she woke up this morning? 
 
2.  How tired did your child seem to be today? 
 

 
A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
 
 
Appendix 3 
Patient Global Impression of Change (PGIC) and Patient Global 
Impression of Symptoms (PGIS) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confidential 
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Amendment 06, 21 December 2021 

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Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Page 1 of 4
Confidential
Amendment 05, 18 March 2020
Appendix 3: Patient Global Impression of Change (PGIC) and Patient Global 
Impression of Symptoms (PGIS)
ITCH
PGIC – CHILD
Please pick the answer below that best describes the overall change in your itch since you started 
taking the study medicine.
Very much better 
 
 Much better
A little better 
 
 No change
A little worse 
 
 Much worse
Very much worse
PGIC – PARENT
Please choose the response below that best describes the overall change in your child’s 
scratching since he/she started taking the study medication.
Very much better 
 
 Moderately better 
A little better
No change
A little worse
 
 Moderately worse 
Very much worse
PGIC – CLINICIAN
Please choose the response below that best describes the overall change in your patient’s 
scratching since he/she started taking the study medication.
Very much better 
 
 Moderately better 
A little better
No change
A little worse
 
 Moderately worse 
Very much worse

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Page 2 of 4
Confidential
Amendment 05, 18 March 2020
PGIS – CHILD
Please choose the answer below that best describes how bad your itch has been the past week.
 
 None 
A little
 
 Medium 
Bad
Very Bad
PGIS – PARENT
Please choose the response below that best describes the severity of your child’s scratching over 
the past week.
None 
Mild
Moderate 
Severe
Very Severe
PGIS – CLINICIAN
Please choose the response below that best describes the severity of your patient’s scratching 
over the past week.
None 
Mild
Moderate 
Severe
Very Severe

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Page 3 of 4
Confidential
Amendment 05, 18 March 2020
SLEEP
PGIC – CHILD
Please choose the answer below that best describes the overall change in your sleep problems 
since you started taking the study medicine.
Very much better 
 
 Much better
A little better 
 
 No change
A little worse 
 
 Much worse
Very much worse
PGIC – PARENT
Please choose the response below that best describes the overall change in your child’s sleep
problems since he/she started taking the study medication.
Very much better 
 
 Moderately better 
A little better
No change
A little worse
 
 Moderately worse 
Very much worse
PGIC – CLINICIAN
Please choose the response below that best describes the overall change in your patient’s sleep 
problems since he/she started taking the study medication.
Very much better 
 
 Moderately better 
A little better
No change
A little worse
 
 Moderately worse 
Very much worse
PGIS – CHILD
Please choose the answer below that best describes how bad your sleep problems have been 
over the past week.
 
 None 
A little
 
 Medium 
Bad

A4250 – IND 130591 
EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Page 4 of 4
Confidential
Amendment 05, 18 March 2020
Very Bad
PGIS – PARENT
Please choose the response below that best describes the severity of your child’s sleep problems 
over the past week.
None 
Mild
Moderate 
Severe
Very Severe
PGIS – CLINICIAN
Please choose the response below that best describes the severity of your patient’s sleep
problems over the past week.
None 
Mild
Moderate 
Severe
Very Severe

 
A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
 
 
Appendix 4 
Pediatric Quality of Life Inventory (PedQL) Questionnaire 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confidential 
101 
Amendment 06, 21 December 2021 

PedsQL 4.0 - Parent (2-4) 
01/00 
Not to be reproduced without permission 
Copyright © 1998 JW Varni, Ph.D. All rights reserved 
PedsQL-4.0-Core-PT - United States/English – Original version 
PedsQL-4.0-Core-PT_AU4.0_eng-USori 
 
 
DIRECTIONS 
On the following page is a list of things that might be a problem for your child. 
Please tell us how much of a problem each one has been for your child 
during the past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
 
PedsQL 
™
™ 
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee 
IInnvveennttoorryy 
Version 4.0 
 
 
PARENT REPORT for TODDLERS (ages 2-4) 
 
 
 
ID#  
 
Date: 
 

 
 
 
How much of a problem is this for you? 
 
 
Not at all 
Sometimes 
A lot 
© 
© 
® 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
PedsQL 4.0 - (5-7) 
01/00 
Not to be reproduced without permission 
Copyright© 1998 JW Varni, Ph.D. All rights reserved. 
PedsQL-4.0-Core - United States/English - Original version 
PedsQL-4.0-Core-YC_AU4.0_eng-USori 

PedsQL 4.0 - Parent (5-7) 
01/00 
Not to be reproduced without permission 
Copyright © 1998 JW Varni, Ph.D. All rights reserved 
PedsQL-4.0-Core-PYC – United States/English – Original version 
PedsQL-4.0-Core-PYC_AU4.0_eng-USori 
 
 
DIRECTIONS 
On the following page is a list of things that might be a problem for your child. 
Please tell us how much of a problem each one has been for your child 
during the past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
 
PedsQL 
™
™ 
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee 
IInnvveennttoorryy 
Version 4.0 
 
 
PARENT REPORT for YOUNG CHILDREN (ages 5-7) 
 
 
 
ID#  
 
Date: 
 

PedsQL 4.0 - (8-12) 
01/00 
Not to be reproduced without permission 
Copyright © 1998 JW Varni, Ph.D. All rights reserved 
PedsQL-4.0-Core-C – United States/English – Original version 
PedsQL-4.0-Core-C_AU4.0_eng-USori 
 
 
DIRECTIONS 
On the following page is a list of things that might be a problem for you. 
Please tell us how much of a problem each one has been for you 
during the past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
 
PedsQL 
™
™ 
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee 
IInnvveennttoorryy 
Version 4.0 
 
 
CHILD REPORT (ages 8-12) 
 
 
 
ID#  
 
Date: 
 

PedsQL 4.0 - Parent (8-12) 
01/00 
Not to be reproduced without permission 
Copyright © 1998 JW Varni, Ph.D. All rights reserved 
PedsQL-4.0-Core-PC – United States/English – Original version 
PedsQL-4.0-Core-PC_AU4.0_eng-USori 
 
 
DIRECTIONS 
On the following page is a list of things that might be a problem for your child. 
Please tell us how much of a problem each one has been for your child 
during the past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
 
PedsQL 
™
™ 
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee 
IInnvveennttoorryy 
Version 4.0 
 
 
PARENT REPORT for CHILDREN (ages 8-12) 
 
 
 
ID#  
 
Date: 
 

PedsQL 4.0 - Parent (13-18) 
01/00 
Not to be reproduced without permission 
Copyright © 1998 JW Varni, Ph.D. All rights reserved 
PedsQL-4.0-Core-PA – United States/English – Original version 
PedsQL-4.0-Core-PA_AU4.0_eng-USori 
 
 
DIRECTIONS 
On the following page is a list of things that might be a problem for your teen. 
Please tell us how much of a problem each one has been for your teen 
during the past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
 
PedsQL 
™
™ 
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee 
IInnvveennttoorryy 
Version 4.0 
 
 
PARENT REPORT for TEENS (ages 13-18) 
 
 
 
ID# 
 
Date: 
 

PedsQL 4.0 - (13-18) 
01/00 
Not to be reproduced without permission 
Copyright © 1998 JW Varni, Ph.D. All rights reserved 
PedsQL-4.0-Core-A – United States/English – Original version 
PedsQL-4.0-Core-A_AU4.0_eng-USori 
 
 
DIRECTIONS 
On the following page is a list of things that might be a problem for you. 
Please tell us how much of a problem each one has been for you 
during the past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
 
PedsQL 
™
™ 
PPeeddiiaattrriicc Q
Quuaalliittyy ooff LLiiffee 
IInnvveennttoorryy 
Version 4.0 
 
 
TEEN REPORT (ages 13-18) 
 
 
 
ID#  
 
Date: 
 

PedsQL 4.0 - (18-25) 
2/07 
Not to be reproduced without permission 
Copyright © 1998 JW Varni, Ph.D. All rights reserved 
PedsQL-4.0-Core-Yad – United States/English – Original version 
PedsQL-4.0-Core-Yad_AU4.0_eng-USori 
 
 
DIRECTIONS 
On the following page is a list of things that might be a problem for you. 
Please tell us how much of a problem each one has been for you 
during the past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
PedsQL
™
™
 
YYoouunngg AAdduulltt Q
Quuaalliittyy ooff LLiiffee 
IInnvveennttoorryy 
Version 4.0 
 
 
YOUNG ADULT REPORT (ages 18-25) 
 
 
 
ID#  
 
Date: 
 

Copyright © 1998 JW Varni, PhD. 
PedsQL 2.0 - Parent Family Impact 
06/04 
Not to be reproduced without permission 
PedsQL-2.0-FIM - United States/English – Original version 
PedsQL-2.0-FIM_AU2.0_eng-USori 
 
 
DIRECTIONS 
Families of children sometimes have special concerns or difficulties because of the 
child’s health. On the following page is a list of things that might be a problem for 
you. Please tell us how much of a problem each one has been for you during the 
past ONE month by circling: 
0 if it is never a problem 
1 if it is almost never a problem 
2 if it is sometimes a problem 
3 if it is often a problem 
4 if it is almost always a problem 
There are no right or wrong answers. 
If you do not understand a question, please ask for help. 
 
 
PedsQL
™
 
Family Impact Module 
Version 2.0 
 
 
PARENT REPORT 
 
 
 
ID# 
 
Date: 
 

 
A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
 
 
Appendix 5 
Guideline for Fat-Soluble Vitamin Supplementation 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confidential 
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EudraCT 2017-002325-38
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Confidential
Amendment 05, 18 March 2020
Page 1 of 2
Appendix 5: Guideline for Fat-Soluble Vitamin Supplementation
Cholestasis predisposes to fat-soluble vitamin deficiencies. Fat-soluble vitamin levels, 
i.e., vitamins A and E, 25-hydroxy vitamin D, and INR (surrogate for vitamin K) are 
measured routinely during the study. If a patient has any fat-soluble vitamin level(s) that 
are out of range, vitamin supplementation adjustments may be required. Below are 
suggested guidelines for fat-soluble vitamin deficiency treatment [Venkat 2014; 
Shneider 2012]. Additional patient monitoring and/or treatment strategies may be 
warranted at the discretion of the investigator. 
Target Fat-soluble Vitamin Levels and Replacement Regimens
Vitamin
Target Range 
(Serum Level)
Supplementation Strategy
A (retinol)
19 to 77 µg/dL* 
retinol:retinol-binding 
protein molar ratio > 0.8 
Increments of 5000 IU (up to 25,000 
to 50,000 IU/day) orally or monthly 
intramuscular administration of 
50,000 IU**
D (25-hydroxy 
vitamin D)
15 to 45 ng/mL*
Increments of 1200 to 8000 IU 
orally daily of cholecalciferol or
ergocalciferol; alternatively 
calcitriol at 0.05 to 0.2 µg/kg/day*
E (  tocopherol)
3.8 to 20.3 µg/mL 
vitamin E:total serum 
lipids ratio >0.6 mg/g
Increments of 25 IU/kg of
d- -tocopheryl polyethylene glycol
– 1000 succinate (TPGS) orally 
daily (to 100 IU/kg/day)
K (phytonadione)
INR 1.2
1.2 <INR 1.5: 2.5 mg
vitamin K orally daily
1.5 <INR 1.8: 2.0 to 5.0 mg
vitamin K intramuscular and
2.5 mg vitamin K orally daily
INR >1.8: 2.0 to 5.0 mg vitamin 
K intramuscular and 5.0 mg 
vitamin K orally daily
*Clinical practice may vary. This is meant as a guidance only and does not override local standard of care. Investigators
should provide best case practices for management and treatment
 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Confidential 
Amendment 05, 18 March 2020 
Page 2 of 2 
 
 
 
** For further detail regarding age related Tolerable Upper Intake (UL) for preformed vitamin A please refer to page 163 in 
the European Food Safety Authority guidance: Tolerable Upper Intake Levels for Vitamins and Minerals; Scientific Committee 
on food Scientific Panel on Dietetic Products, Nutrition and Allergies 
http://www.efsa.europa.eu/sites/default/files/efsa_rep/blobserver_assets/ndatolerableuil.pdf 

 
A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
 
 
Appendix 6 
Contraceptive Requirements 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confidential 
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Amendment 06, 21 December 2021 

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Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008
Page 1 of 2
Confidential
Amendment 05, 18 March 2020
Appendix 6: Contraceptive Requirements
A woman is considered of childbearing potential (WOCBP), i.e. fertile, following 
menarche and until becoming post-menopausal unless permanently sterile. Permanent 
sterilisation methods include hysterectomy, bilateral salpingectomy and bilateral 
oophorectomy.
Contraceptive methods, or combinations of contraceptive methods, for males and females 
that can achieve a failure rate of less than 1% per year when used consistently and 
correctly are considered as highly effective birth control methods and must be used at 
least to up to 90 days following the last day of treatment. 
Such methods include:
Combined (estrogen and progestogen containing) hormonal contraception 
associated with inhibition of ovulation:
o
oral
o
intravaginal
o
transdermal
Progestogen-only hormonal contraception associated with inhibition of ovulation:
o
oral
o
injectable
o
implantable
Intrauterine device (IUD)
Intrauterine hormone-releasing system (IUS) 
Bilateral tubal occlusion
Vasectomised partner 
 
Sexual abstinence 
Sexual abstinence is considered a highly effective method only if defined as refraining 
from heterosexual intercourse during the entire study period up to at least 90 days after 
the last day of treatment. The reliability of sexual abstinence needs to be evaluated in 
relation to the duration of the clinical trial and the preferred and usual lifestyle of the 

A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
Page 2 of 2 
Confidential 
Amendment 05, 18 March 2020 
 
 
 
subject. Periodic abstinence (e.g., calendar, ovulation, symptothermal, post-ovulation 
methods) and withdrawal are not acceptable methods of contraception. 
Requirements according to “Recommendations related to contraception and pregnancy 
testing in clinical trials”, HMA CTFG (Clinical Trial Facilitation Group), 2014 

 
A4250 – IND 130591 
EudraCT 2017-002325-38 
Module 5: Clinical Study Reports 
M5.3.5.1 – Protocol A4250-008 
 
 
Appendix 7 
Blood Volumes 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confidential 
128 
Amendment 06, 21 December 2021 

ICON Central Laboratories 
Scientific Affairs 
Estimated Blood Volume Request 
Version: 15.0 
Protocol#: A4250-008 
SPONSOR: Albireo 
Age Group 0 months to 30 years of age 
Estimated Blood Volume Request (MS Excel) 
Eff. 25 October 2011, Vs. 1 
QS#: MA706App105 
Page 3 of 3 
 
 
Visit^ 
Testing^1-9 
Tube 
volume 
(mL) 
Tube 
Type 
# of 
Collection 
Tubes 
# of 
Aliquots 
Volume 
(mLs) 
Volume/ 
visit 
(mL) 
Volume/
visit 
(tsp) 
Volume/ 
visit 
(TBS) 
#5. Autotaxin serum samples will be tested at LGC 
#6. For subjects requiring optional pregnancy testing, collect 1.1 mL SST 
#7. Optional Sample. Only collected if required 
#8. Collection requirements for Extension Period Visit added per provision of schedule of assessments provided by sponsor for utiliztion in an upcoming revised protocol. 
#9. For patients who experience a hepatic adverse event and/or hepatic decompensation, collect 1.1. mL Plasma for PK 
 
Created by: Jennifer Rodriguez, Protocol Review 
Date: 19-Mar-2020