A Multicenter, Phase 3, Randomized, Double-Blind, Placebo-Controlled Study Evaluating the Efficacy and Safety of Bimekizumab in the Treatment of Subjects With Active Psoriatic Arthritis
Phase: PHASE3
Conditions: Psoriatic Arthritis
Sponsor: UCB Biopharma SRL

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 1 of 142 
PROTOCOL PA0011 AMENDMENT 2 
A MULTICENTER, PHASE 3, RANDOMIZED, DOUBLE-BLIND, 
PLACEBO-CONTROLLED STUDY EVALUATING THE 
EFFICACY AND SAFETY OF BIMEKIZUMAB IN THE 
TREATMENT OF SUBJECTS WITH ACTIVE PSORIATIC 
ARTHRITIS 
PHASE 3 
EudraCT Number: 2017-002804-29 
IND Number: 128708 
Sponsor: 
UCB Biopharma SRL 
Allée de la Recherche 60 
1070 Brussels 
BELGIUM 
 
 
Protocol/Amendment number 
Date 
Type of amendment 
Final Protocol 
29 Nov 2018 
Not applicable 
Protocol Amendment 1 
14 May 2020 
Substantial 
Protocol Amendment 2 
01 Apr 2021 
Substantial 
Confidential Material 
Confidential 
This document is the property of UCB and may not – in full or in part – be passed on, 
reproduced, published, or otherwise used without the express permission of UCB. 
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 2 of 142 
STUDY CONTACT INFORMATION 
Sponsor 
UCB Biopharma SRL 
Allée de la Recherche 60  
1070 Brussels  
BELGIUM 
Sponsor Study Physician 
Name: 
 
Address: 
UCB Celltech Ltd 
208 Bath Road 
Slough SL1 3WE 
UNITED KINGDOM 
Phone: 
 
Clinical Project Manager 
Name: 
 
Address: 
UCB Biopharma SRL 
Chemin du Foriest 
Brain-l'Alleud B-1420 
Belgium 
Phone: 
 
Clinical Trial Biostatistician 
Name: 
 
Address: 
UCB BIOSCIENCES Inc.  
4000 Paramount Pkwy, 
 
Morrisville, NC 27560 
UNITED STATES 
Phone: 
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 3 of 142 
Clinical Monitoring Contract Research Organization 
Name: 
PAREXEL International (IRL) Limited-Ireland 
Address: 
Ireland Limited at 70 Sir John Rogerson’s Quay, Dublin 2, Ireland 
Phone: 
+353-(1)-477-3171 
Fax: 
+353-(1)-477-3308 
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 4 of 142 
SERIOUS ADVERSE EVENT REPORTING 
Serious adverse event reporting (24h) 
All serious adverse events will be reported and transmitted to Patient Safety through the 
eCRF system. The numbers below are to be used to send ancillary documentation only 
(discharge summaries, death certificates, etc) or in the event that the electronic reporting 
(eCRF) is not available. 
Fax 
Europe and Rest of the World: +32-2-386-24-21 
USA and Canada: +1-800-880-6949 or +1-866-890-3175 
Email 
Global: DS_ICT@ucb.com  
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 5 of 142 
TABLE OF CONTENTS 
LIST OF ABBREVIATIONS .................................................................................................. 11 
1 
SUMMARY ..................................................................................................................... 16 
2 
INTRODUCTION ........................................................................................................... 17 
2.1 
Psoriatic arthritis .......................................................................................................... 17 
2.1.1 
Psoriatic arthritis epidemiology ........................................................................... 17 
2.1.2 
Current treatments for psoriatic arthritis .............................................................. 17 
2.2 
Bimekizumab ............................................................................................................... 18 
2.2.1 
Nonclinical ........................................................................................................... 18 
2.2.2 
Clinical ................................................................................................................. 19 
2.2.2.1 
Completed studies ..................................................................................... 19 
2.2.2.2 
Ongoing studies ......................................................................................... 22 
3 
STUDY OBJECTIVES .................................................................................................... 23 
3.1 
Primary objective ......................................................................................................... 23 
3.2 
Secondary objectives ................................................................................................... 23 
3.3 
Other objectives ........................................................................................................... 23 
4 
STUDY VARIABLES ..................................................................................................... 24 
4.1 
Efficacy variables......................................................................................................... 24 
4.1.1 
Primary efficacy variable ..................................................................................... 24 
4.2 
Secondary variables ..................................................................................................... 24 
4.2.1 
Secondary efficacy variables ............................................................................... 24 
4.2.2 
Secondary safety variables .................................................................................. 24 
4.3 
Other variables ............................................................................................................. 24 
4.3.1 
Other efficacy variables ....................................................................................... 24 
4.3.2 
Other safety variables .......................................................................................... 26 
4.3.3 
Pharmacokinetic variable ..................................................................................... 27 
4.3.4 
Pharmacogenomic variables ................................................................................ 27 
4.3.5 
Immunological variables ..................................................................................... 27 
5 
STUDY DESIGN ............................................................................................................. 27 
5.1 
Study description ......................................................................................................... 27 
5.2 
Screening Period/Baseline ........................................................................................... 28 
5.2.1 
Within-study rescreening/retesting requirements ................................................ 28 
5.3 
Treatment Period .......................................................................................................... 28 
5.3.1 
Double-Blind Treatment Period .......................................................................... 28 
5.4 
Safety Follow-Up Visit ................................................................................................ 29 
5.5 
Study duration per subject ........................................................................................... 29 
5.6 
Planned number of subjects and sites .......................................................................... 29 
5.7 
Anticipated regions and countries ................................................................................ 29 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 6 of 142 
5.8 
Schedule of study assessments..................................................................................... 29 
5.9 
Schematic diagram ....................................................................................................... 35 
5.10 
Rationale for study design and selection of dose ......................................................... 35 
6 
SELECTION AND WITHDRAWAL OF SUBJECTS ................................................... 36 
6.1 
Inclusion criteria .......................................................................................................... 36 
6.2 
Exclusion criteria ......................................................................................................... 37 
6.3 
Withdrawal criteria ...................................................................................................... 40 
6.3.1 
Potential drug-induced liver injury IMP discontinuation criteria ........................ 43 
7 
STUDY TREATMENTS ................................................................................................. 43 
7.1 
Description of investigational medicinal products ...................................................... 43 
7.2 
Treatments to be administered ..................................................................................... 44 
7.3 
Packaging ..................................................................................................................... 44 
7.4 
Labeling ....................................................................................................................... 44 
7.5 
Handling and storage requirements ............................................................................. 44 
7.6 
Drug accountability ...................................................................................................... 45 
7.7 
Procedures for monitoring subject compliance ............................................................ 45 
7.8 
Concomitant medications/treatments ........................................................................... 45 
7.8.1 
Permitted concomitant treatments (medications and therapies) .......................... 46 
7.8.1.1 
Psoriasis treatments ................................................................................... 46 
7.8.2 
Prohibited concomitant treatments (medications and therapies) ......................... 46 
7.8.3 
Vaccines ............................................................................................................... 48 
7.9 
Blinding........................................................................................................................ 48 
7.9.1 
Procedures for maintaining and breaking the treatment blind ............................. 48 
7.9.1.1 
Maintenance of study treatment blind ....................................................... 48 
7.9.1.2 
Breaking the treatment blind in an emergency situation ........................... 48 
7.10 
Randomization and numbering of subjects .................................................................. 49 
8 
STUDY PROCEDURES BY VISIT ............................................................................... 49 
8.1 
Screening Period/Baseline ........................................................................................... 49 
8.1.1 
Screening ............................................................................................................. 49 
8.1.2 
Baseline (Day 1) .................................................................................................. 51 
8.2 
Double-Blind Treatment Period ................................................................................... 52 
8.2.1 
Week 4 ................................................................................................................. 52 
8.2.2 
Week 8 ................................................................................................................. 53 
8.2.3 
Week 12 ............................................................................................................... 54 
8.2.4 
Week 16 ............................................................................................................... 55 
8.3 
Early Termination Visit ............................................................................................... 57 
8.4 
Safety Follow-Up Visit (20 weeks [-3 days/+7 days] after the final dose) ................. 58 
8.5 
Unscheduled Visits ...................................................................................................... 59 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 7 of 142 
9 
ASSESSMENT OF EFFICACY ...................................................................................... 60 
9.1 
Joint assessments ......................................................................................................... 60 
9.1.1 
68/66 joint evaluation for ACR response and verification of Inclusion 
Criterion 5 ............................................................................................................ 60 
9.1.2 
28 joint evaluation for determination of DAS28(CRP) ....................................... 61 
9.2 
ACR20, ACR50, and ACR70 response ....................................................................... 61 
9.3 
Patient’s Global Assessments ...................................................................................... 61 
9.3.1 
Patient’s Global Assessment of Psoriatic Arthritis (PGA-PsA) .......................... 61 
9.3.2 
Patient’s Global Assessment of Arthritis (PGA-arthritis) ................................... 62 
9.4 
Physician’s Global Assessments .................................................................................. 62 
9.4.1 
Physician’s Global Assessment of Psoriatic Arthritis (PhGA-PsA) .................... 62 
9.4.2 
Physician’s Global Assessment of Arthritis (PhGA-Arthritis) ............................ 62 
9.5 
Patient’s Assessment of Arthritis Pain (PtAAP) .......................................................... 62 
9.6 
Health Assessment Questionnaire-Disability Index score (HAQ-DI) ......................... 63 
9.7 
High sensitivity C-reactive protein levels (hs-CRP) .................................................... 63 
9.8 
Evaluation of psoriasis ................................................................................................. 63 
9.8.1 
Body surface area psoriasis (BSA-PSO) ............................................................. 63 
9.8.2 
Psoriasis Area and Severity Index (PASI) ........................................................... 63 
9.8.3 
Investigator’s Global Assessment (IGA) ............................................................. 64 
9.8.4 
Modified Nail Psoriasis Severity Index (mNAPSI) ............................................. 65 
9.9 
Minimal Disease Activity (MDA) and Very Low Disease Activity (VLDA) ............. 65 
9.10 
Disease Activity Index for Psoriatic Arthritis (DAPSA) ............................................. 65 
9.11 
Disease Activity Score-28 based on C-reactive protein (DAS28[CRP]) ..................... 66 
9.12 
Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) ............................... 66 
9.13 
Leeds Enthesitis Index (LEI) ....................................................................................... 66 
9.14 
Spondyloarthritis Research Consortium of Canada (SPARCC) .................................. 66 
9.15 
Leeds Dactylitis Index (LDI) ....................................................................................... 66 
9.16 
Psoriatic Arthritis Quality of Life (PsAQoL) .............................................................. 67 
9.17 
Psoriatic Arthritis Impact of Disease-12 (PsAID-12) .................................................. 67 
9.18 
Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue subscale ......... 67 
9.19 
Short-Form 36-item Health Survey (SF-36) ................................................................ 67 
9.20 
Euro Quality of life 5-Dimensions-3 Level (EQ-5D-3L) ............................................ 68 
9.21 
Work Productivity and Activity Impairment Questionnaire – Specific Health Problem 
(WPAI-SHP) ................................................................................................................ 68 
9.22 
Psoriatic Arthritis Response Criteria (PsARC) ............................................................ 68 
9.23 
Psoriatic Arthritis Disease Activity Score (PASDAS) ................................................ 68 
10 ASSESSMENT OF PHARMACOKINETIC AND PHARMACOGENOMIC 
VARIABLES ................................................................................................................... 69 
10.1 
Pharmacokinetic variable ............................................................................................. 69 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 8 of 142 
10.2 
Pharmacogenomic variables ........................................................................................ 69 
11 ASSESSMENT OF IMMUNOLOGICAL VARIABLES ............................................... 70 
12 ASSESSMENT OF SAFETY .......................................................................................... 70 
12.1 
Adverse events ............................................................................................................. 70 
12.1.1 
Definitions ........................................................................................................... 70 
12.1.1.1 
Adverse event ............................................................................................ 70 
12.1.1.2 
Serious adverse event ................................................................................ 71 
12.1.1.3 
Adverse events of special interest ............................................................. 72 
12.1.1.4 
Other safety topics of interest .................................................................... 73 
12.1.2 
Procedures for reporting and recording adverse events ....................................... 73 
12.1.2.1 
Description of adverse events .................................................................... 73 
12.1.2.2 
Rule for repetition of an adverse event...................................................... 73 
12.1.2.3 
Additional procedures for reporting serious adverse events ..................... 74 
12.1.3 
Follow up of adverse events ................................................................................ 74 
12.1.4 
Pregnancy ............................................................................................................ 75 
12.1.5 
Suspected transmission of an infectious agent via a medicinal product .............. 76 
12.1.6 
Overdose of investigational medicinal product ................................................... 76 
12.1.7 
Safety signal detection ......................................................................................... 76 
12.2 
Laboratory measurements ............................................................................................ 76 
12.2.1 
Evaluation of potential drug-induced liver injury................................................ 78 
12.2.1.1 
Consultation with Medical Monitor and local hepatologist ...................... 83 
12.2.1.2 
Immediate action: determination of IMP discontinuation ......................... 83 
12.2.1.3 
Testing: identification/exclusion of alternative etiology ........................... 84 
12.2.1.4 
Follow-up evaluation ................................................................................. 86 
12.3 
Other safety measurements .......................................................................................... 86 
12.3.1 
Vital signs ............................................................................................................ 86 
12.3.2 
Body weight and height ....................................................................................... 87 
12.3.3 
Physical examination ........................................................................................... 87 
12.3.4 
12-lead electrocardiogram ................................................................................... 87 
12.3.5 
Patient Health Questionnaire-9 (PHQ-9) ............................................................. 87 
12.3.6 
Assessment and management of TB and TB risk factors .................................... 87 
12.3.6.1 
Tuberculosis assessment by IGRA ............................................................ 91 
12.3.6.2 
Chest x-ray for tuberculosis ...................................................................... 91 
12.3.6.3 
Tuberculosis questionnaire ........................................................................ 91 
12.3.6.4 
Tuberculosis management ......................................................................... 91 
12.3.7 
Pregnancy testing ................................................................................................. 92 
12.3.8 
Assessment of suicidal ideation and behavior ..................................................... 92 
13 STUDY MANAGEMENT AND ADMINISTRATION ................................................. 93 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 9 of 142 
13.1 
Adherence to protocol .................................................................................................. 93 
13.2 
Monitoring ................................................................................................................... 93 
13.2.1 
Definition of source data ..................................................................................... 93 
13.2.2 
Source data verification ....................................................................................... 94 
13.3 
Data handling ............................................................................................................... 94 
13.3.1 
Case Report form completion .............................................................................. 94 
13.3.2 
Database entry and reconciliation ........................................................................ 94 
13.3.3 
Subject Screening and Enrollment log/Subject Identification Code list.............. 95 
13.4 
Termination of the study .............................................................................................. 95 
13.5 
Archiving and data retention ........................................................................................ 95 
13.6 
Audit and inspection .................................................................................................... 96 
13.7 
Good Clinical Practice ................................................................................................. 96 
14 STATISTICS ................................................................................................................... 96 
14.1 
Definition of analysis sets ............................................................................................ 96 
14.2 
General statistical considerations ................................................................................. 97 
14.3 
Planned efficacy analyses ............................................................................................ 97 
14.3.1 
Analysis of the primary and secondary efficacy variables .................................. 97 
14.3.1.1 
Analysis of the primary efficacy variable ................................................. 98 
14.3.1.2 
Analyses of the secondary efficacy variables .......................................... 100 
14.3.2 
Analyses of the other efficacy variables ............................................................ 101 
14.3.3 
Subgroup analyses ............................................................................................. 102 
14.4 
Planned safety analyses.............................................................................................. 103 
14.4.1 
Safety analyses ................................................................................................... 103 
14.5 
Other planned analyses .............................................................................................. 103 
14.5.1 
Pharmacokinetics analyses ................................................................................ 103 
14.5.2 
Immunological analyses .................................................................................... 103 
14.6 
Handling of protocol deviations................................................................................. 103 
14.7 
Handling of dropouts or missing data ........................................................................ 104 
14.8 
Planned interim analysis and data monitoring ........................................................... 105 
14.8.1 
Data monitoring ................................................................................................. 105 
14.8.2 
Interim analysis .................................................................................................. 105 
14.9 
Determination of sample size ..................................................................................... 105 
14.9.1 
Power calculation for primary endpoint ............................................................ 106 
14.9.2 
Power calculations for secondary endpoints ...................................................... 106 
15 ETHICS AND REGULATORY REQUIREMENTS .................................................... 107 
15.1 
Informed consent ....................................................................................................... 107 
15.2 
Subject identification cards ........................................................................................ 108 
15.3 
Institutional Review Boards and Independent Ethics Committees ............................ 108 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 10 of 142 
15.4 
Subject privacy........................................................................................................... 109 
15.5 
Protocol amendments ................................................................................................. 109 
16 FINANCE, INSURANCE, AND PUBLICATION ....................................................... 109 
17 REFERENCES .............................................................................................................. 109 
18 APPENDICES ............................................................................................................... 114 
18.1 
Classification Criteria for Psoriatic Arthritis ............................................................. 114 
18.2 
Protocol Amendment 1 .............................................................................................. 115 
18.3 
Protocol Amendment 2 .............................................................................................. 129 
19 DECLARATION AND SIGNATURE OF INVESTIGATOR ..................................... 141 
20 SPONSOR DECLARATION ........................................................................................ 142 
 
LIST OF TABLES 
Table 5-1: 
Schedule of study assessments......................................................................... 30 
Table 7‒1: 
Prohibited or restricted medications and required wash-out periods ............... 46 
Table 7-2: 
Additional prohibited psoriasis treatments ...................................................... 48 
Table 9-1: 
Swelling and tenderness grading ..................................................................... 61 
Table 9-2: 
Body areas for calculation of percent BSA for PASI ...................................... 64 
Table 9-3: 
Five-point IGA ................................................................................................. 64 
Table 12-1: 
Anticipated SAEs for the population of subjects with PsA ............................. 72 
Table 12-2: 
Laboratory measurements ................................................................................ 78 
Table 12‒3: 
Required investigations and follow-up for PDILI ........................................... 80 
Table 12-4: 
PDILI laboratory measurements ...................................................................... 85 
Table 12-5: 
PDILI information to be collected ................................................................... 86 
Table 18-1: 
CASPAR Criteria ........................................................................................... 114 
 
LIST OF FIGURES 
Figure 5-1: 
Study schematic diagram ................................................................................. 35 
Figure 12-1: 
Schematic diagram of TB test results and study eligibility ............................. 89 
Figure 12‒2: Schematic diagram of TB test results during the study ................................... 90 
Figure 14-1: 
Sequential testing procedure of primary/secondary efficacy endpoints 
(fixed sequence testing procedure) .................................................................. 98 
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 11 of 142 
LIST OF ABBREVIATIONS 
ACR 
American College of Rheumatology 
AE 
adverse event 
ALP 
alkaline phosphatase 
ALT 
alanine aminotransferase 
ANCOVA 
analysis of covariance 
AS 
ankylosing spondylitis 
AST 
aspartate aminotransferase 
BA 
bioanalytics 
BASDAI 
Bath Ankylosing Spondylitis Disease Activity Index 
bDMARD 
biologic disease modifying antirheumatic drug 
BP 
blood pressure 
BSA 
body surface area 
CASPAR 
Classification Criteria for Psoriatic Arthritis 
CCP 
cyclic citrullinated peptide 
CDMS 
clinical data management system 
CI 
confidence interval 
cDMARD 
conventional disease-modifying antirheumatic drugs 
COVID-19 
coronavirus disease 2019 
COX-2 
cyclooxygenase-2 
CPM 
Clinical Project Manager 
CRO 
contract research organization 
CRP 
C-reactive protein 
CSR 
Clinical Study Report 
CZP 
certolizumab pegol 
DAPSA 
Disease Activity Index for Psoriatic Arthritis 
DAS28(CRP) 
Disease Activity Score-28 based on C-reactive protein 
DIP 
distal interphalangeal  
DMARD 
disease-modifying antirheumatic drug 
DMC 
Data Monitoring Committee 
DNA 
deoxyribonucleic acid 
ECG 
electrocardiogram 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 12 of 142 
eCRF 
electronic Case Report Form 
eC-SSRS 
electronic Columbia-Suicide Severity Rating Scale 
EDC 
electronic data capture 
ePRO 
electronic Patient-Reported Outcome 
EQ-5D-3L 
EuroQol-5 Dimensions-3 Level 
ET 
Early Termination 
EudraCT 
European Union Drug Regulating Authorities Clinical Trials 
FACIT 
Functional Assessment of Chronic Illness Therapy 
FAS 
Full Analysis Set 
GCP 
Good Clinical Practice 
GI  
gastrointestinal  
GMP 
Good Manufacturing Practice 
HAQ-DI 
Health Assessment Questionnaire – Disability Index 
HCQ 
hydroxychloroquine 
HCV 
hepatitis C virus 
HDL 
high density lipoprotein 
HIV 
human immunodeficiency virus 
HLA-B27 
human leukocyte antigen B27 
HRQoL 
Health-Related Quality of Life 
HS 
hidradenitis suppurativa 
hs-CRP 
high sensitivity C-reactive protein 
IB 
Investigator’s Brochure 
IBD 
inflammatory bowel disease 
ICF 
Informed Consent form 
ICH 
International Council for Harmonisation 
IEC 
Independent Ethics Committee 
IGA 
Investigator’s Global Assessment 
IGRA 
interferon gamma release assay 
IL 
interleukin 
IMP 
investigational medicinal product 
IRB 
Institutional Review Board 
iv 
intravenous 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 13 of 142 
IXRS 
interactive voice or web response system  
LDI 
Leeds Dactylitis Index 
LDL 
low density lipoprotein 
LEF 
leflunomide 
LEI 
Leeds Enthesitis Index 
LN 
natural logarithm 
LTB 
latent tuberculosis 
LTBI 
latent tuberculosis infection 
MAR 
missing at random 
MCMC 
Markov-Chain Monte Carlo 
MCS 
Mental Component Summary 
MDA 
Minimal Disease Activity 
MI 
multiple imputation 
mNAPSI 
modified Nail Psoriasis Severity Index 
mRNA 
messenger ribonucleic acid 
MTX 
methotrexate 
NRI 
Nonresponder Imputation 
NSAID 
nonsteroidal anti-inflammatory drug 
NTMB 
nontuberculous mycobacteria 
OC 
observed case 
OLE 
open-label extension  
PASDAS 
Psoriatic Arthritis Disease Activity Score 
PASI 
Psoriasis Area and Severity Index 
PCS 
Physical Component Summary 
PD 
pharmacodynamics 
PDILI 
potential drug-induced liver injury 
PFS 
prefilled syringe 
PGADA 
Patient’s Global Assessment of Disease Activity 
PGA-Arthritis 
Patient’s Global Assessment of Arthritis 
PGA-PsA 
Patient’s Global Assessment of Psoriatic Arthritis 
PhGADA 
Physician’s Global Assessment of Disease Activity 
PhGA-arthritis 
Physician’s Global Assessment of Arthritis 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 14 of 142 
PhGA-PsA 
Physician’s Global Assessment of Psoriatic Arthritis 
PHQ-9 
Patient Health Questionnaire-9 
PK 
pharmacokinetic 
PK-PPS 
Pharmacokinetics Per-Protocol Set 
PPS 
Per-Protocol Set 
PS 
Patient Safety 
PsA 
psoriatic arthritis 
PsAID-12 
Psoriatic Arthritis Impact of Disease-12 
PsAQoL 
Psoriatic Arthritis Quality of Life 
PsARC 
Psoriatic Arthritis Response Criteria  
PSO 
psoriasis 
PtAAP 
Patient’s Assessment of Arthritis Pain 
Q4W 
every 4 weeks 
RA 
rheumatoid arthritis 
RNA 
ribonucleic acid 
RS 
Randomized Set 
SAE 
serious adverse event 
SAP 
Statistical Analysis Plan 
sc 
subcutaneous(ly) 
SD 
standard deviation 
SF-36 
Short-Form 36-item Health Survey 
SFU 
Safety Follow-Up 
SJC 
swollen joint count 
SOP 
Standard Operating Procedure 
SPARCC 
Spondyloarthritis Research Consortium of Canada 
SS 
Safety Set 
SSZ 
sulfasalazine 
TB 
tuberculosis 
TEAE 
treatment-emergent adverse event 
TJC 
tender joint count 
TNF 
tumor necrosis factor 
TNFα 
tumor necrosis factor alpha 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 15 of 142 
TNFα-IR 
TNFα-inadequate responders 
UC 
ulcerative colitis 
ULN 
upper limit of normal 
VAS 
visual analog scale 
VLDA 
Very Low Disease Activity 
WPAI-SHP 
Work Productivity and Activity Impairment Questionnaire – Specific 
Health Problem 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 16 of 142 
1 
SUMMARY 
This is a Phase 3, multicenter, randomized, double-blind, placebo-controlled study to evaluate 
the efficacy and safety of bimekizumab in subjects with active psoriatic arthritis (PsA). To be 
eligible to participate in this study, subjects must be adults with a diagnosis of active PsA based 
on the Classification Criteria for Psoriatic Arthritis (CASPAR), and have disease with tender 
joint count (TJC) ≥3 and swollen joint count (SJC) ≥3, as well as an inadequate response (lack of 
efficacy after at least 3 months of therapy at an approved dose) or intolerance to treatment with 
1 or 2 tumor necrosis factor alpha (TNFα) inhibitors for either PsA or psoriasis (PSO). 
The primary objective is to demonstrate the efficacy of bimekizumab administered 
subcutaneously (sc) every 4 weeks (Q4W) for 16 weeks compared with placebo in the treatment 
of prior TNFα-inadequate responder (TNFα-IR) (inadequate or intolerance to prior 
TNFα inhibitors) subjects with active PsA, as assessed by the American College of 
Rheumatology (ACR) 50% response. The secondary efficacy and safety objectives of the study 
are listed in Section 3.2, and other objectives are listed in Section 3.3. 
The primary efficacy variable for this study is the ACR50 at Week 16. The secondary and other 
efficacy variables are listed in Section 4.2.1 and Section 4.3.1, respectively. 
Safety variables are listed in Section 4.2.2 (secondary) and Section 4.3.2 (other). The 
pharmacokinetic (PK), and pharmacogenomic variables are listed in Section 4.3.3, and 
Section 4.3.4, respectively. The immunological variable is listed in Section 4.3.5.  
PA0011 will evaluate the efficacy and safety of bimekizumab 160mg sc Q4W in adult subjects 
with active PsA. The dose regimen was selected based on available efficacy data, safety data, 
and PK/pharmacodynamics (PD) modeling.  
The overall study design consists of a Screening Period (≥14 days to ≤35 days), a 16-week 
placebo-controlled Double-Blind Treatment Period, and a Safety Follow-Up 
(SFU) Visit, 20 weeks after the final dose of investigational medicinal product (IMP) (for 
subjects not entering the open-label extension [OLE] study or who discontinue early, including 
those withdrawn from IMP). The maximum study duration per subject will be up to 37 weeks.  
Subjects completing Week 16 are eligible for enrollment in an OLE study to continue to receive 
bimekizumab. 
Approximately 390 subjects will be randomly assigned in a 2:1 ratio to the following treatment 
groups: bimekizumab 160mg sc Q4W (260 subjects), and placebo (130 subjects). The planned 
number of study sites is approximately 89.  
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 17 of 142 
2 
INTRODUCTION 
2.1 
Psoriatic arthritis 
Psoriatic arthritis is a chronic inflammatory musculoskeletal disorder, which occurs in 
approximately 6% to 41% of people affected by PSO (Ogdie and Weiss, 2015). A substantial 
proportion of subjects have polyarthritis (McHugh et al, 2003). These disorders are distinct from 
rheumatoid arthritis (RA), the prototypical inflammatory arthritis, and generally have an earlier 
onset, distal interphalangeal (DIP) joint involvement, asymmetric distribution, dactylitis 
(inflammation of the whole digit), enthesitis (inflammation at the site of tendon insertion into 
bone), spinal involvement, and an association with the human leukocyte antigen (HLA)-B27 
allele.  
Previous work has implicated various isoforms of the interleukin (IL)-17 cytokine family in the 
pathophysiology of PSO and of PsA (Raychaudhuri et al, 2012; Fujishima et al, 2010; 
Watanabe et al, 2009; Harper et al, 2009; Johansen et al, 2009). Numbers of IL-17A-positive 
cells are increased and localized in psoriatic skin lesions (Fujishima et al, 2010; 
Watanabe et al, 2009; Harper et al, 2009; Johansen et al, 2009), and IL-17A and IL-17F are 
overexpressed in the serum and skin lesions of subjects with PSO (Johansen et al, 2009), while 
IL-17F in particular is a key inflammatory cytokine contributing to PSO pathology 
(Fujishima et al, 2010; Watanabe et al, 2009). Cluster of differentiation (CD) 4 + T helper 17 
(Th17) cells, IL-17A, and IL-17 receptor A (IL-17-RA) have recently been shown to play a role 
in PsA (Raychaudhuri et al, 2012). Anti-IL-17 antibodies have been shown to be effective 
treatments for PSO (Papp et al, 2012; Leonardi et al, 2012; Hueber et al, 2010) and have also 
shown activity in subjects with RA, PsA, and ankylosing spondylitis (AS) (McInnes et al, 2014; 
Mease et al, 2015; Hueber et al, 2010; Genovese et al, 2010). Taken together, these data suggest 
that inhibition of both IL-17A and IL-17F could be therapeutically effective in subjects with 
PSO, PsA, and axial spondyloarthritis. 
2.1.1 
Psoriatic arthritis epidemiology 
Psoriatic arthritis is usually diagnosed years after PSO appears. A substantial proportion of 
subjects have polyarthritis (Gladman, 2015; McHugh et al, 2003). More than 50% of patients 
with PsA experience progressive, erosive arthritis that is often accompanied by pain, fatigue, and 
functional impairment. The combination of joint and skin manifestations of PsA can have a 
profound impact on patient function, well-being, and Health-Related Quality of Life (HRQoL). 
The functional impairments are also associated with significant direct health care costs and 
substantial work-related disability, including a lower rate of employment (Lee et al, 2010, 
Salaffi et al, 2009). 
2.1.2 
Current treatments for psoriatic arthritis 
Disease-modifying anti-rheumatic drugs (DMARDs) and biological agents targeting tumor 
necrosis factor alpha (TNFα), IL-17, and IL-12/23 are effective for the treatment of PsA 
(Kavanaugh et al, 2012; Kavanaugh et al, 2009; Gottlieb et al, 2009; Gladman et al, 2007; 
Genovese et al, 2007; Kavanaugh et al, 2006; Antoni et al, 2005a; Antoni et al, 2005b; 
Mease et al, 2005; Mease et al, 2004; McInnes et al, 2015; Mease et al, 2015). Current treatments 
include DMARDs (hydroxychloroquine, azathioprine, cyclosporine, cyclophosphamide, 
mycophenolic acid, mycophenolate mofetil, sulfasalazine [SSZ], tofacitinib, apremilast, 
methotrexate [MTX], and leflunomide [LEF]), IL-17A inhibitor (secukinumab), and 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 18 of 142 
TNFα inhibitors (infliximab, adalimumab, etanercept, golimumab, and certolizumab pegol 
[CZP]). However, some subjects are not responsive to these treatments (defined as achieving 
ACR20 response criteria), do not maintain a clinical response, or have contraindications or 
intolerance to these agents. The long-term goals of therapy include improvement in symptoms of 
the disease, psoriatic plaque clearance, inhibition of disease progression, and prevention of bone 
destruction. 
2.2 
Bimekizumab 
Bimekizumab (UCB4940) is an engineered, humanized full-length monoclonal antibody of the 
immunoglobulin G1 (IgG1) subclass of approximately 150,000 Dalton, which is expressed in a 
genetically engineered Chinese Hamster Ovarian (CHO) cell line. Bimekizumab has high affinity 
for human IL-17A and human IL-17F, and selectively and potently inhibits the activity of both 
isoforms in vitro. Interleukin-17A and IL-17F are key proinflammatory cytokines believed to 
play important roles in autoimmune and inflammatory diseases. Interleukin-17A has been shown 
to have a role in pathogenesis of several autoimmune disorders and IL-17F has been increasingly 
recognized to contribute to the pathogenesis of a number of inflammatory diseases, including 
PSO, ulcerative colitis, asthma, AS, PsA, and RA (Raychaudhuri et al, 2012; 
Fujishima et al, 2010; Watanabe et al, 2009).  
While anti-IL-17A antibodies have demonstrated efficacy in subjects with PSO, PsA, and AS, 
there is currently no therapeutic approach available that fully inhibits the activity of IL-17F. 
Bimekizumab selectively and potently inhibits the activity of both IL-17A and IL-17F isoforms 
in vitro. Therefore, it permits an evaluation of the potential for additional efficacy, which may be 
conferred by dual inhibition of both cytokines in patients with diseases in which both cytokines 
are active. Furthermore, a proof-of-concept study (PA0007) with bimekizumab in subjects with 
moderate to severe PsA demonstrated a strong efficacy signal that warrants further exploration of 
bimekizumab in this indication. A Phase 2b, dose-ranging study (PA0008) was designed to 
investigate the efficacy and safety of various bimekizumab dose regimens in subjects with active 
PsA. The current Phase 3, randomized, double-blind, placebo-controlled confirmatory study 
(PA0011) is designed to investigate the efficacy and safety of bimekizumab in subjects with 
active PsA. 
2.2.1 
Nonclinical 
There is increasing evidence of the role of IL-17F in various inflammatory diseases. 
Simultaneous inhibition of IL-17A and IL-17F has been shown to be more efficacious than 
inhibition of IL-17A alone in in vitro models. Intravenously or sc administered bimekizumab 
was well tolerated in repeat-dose toxicology studies in Cynomolgus monkeys with dosing up to 
200mg/kg/week for up to 26 weeks. The findings of note varied from study to study but were all 
compatible with decreased muco-epidermal immunity induced by the inhibition of IL-17A and F 
signaling. They consisted of diarrhea-related to infectious enteritis, asymptomatic proliferation of 
a protozoan commonly found in the Cynomolgus monkey, Balantidium coli, superficial 
dermatitis associated with increased bacterial load on the skin (mainly gram-positive cocci, 
including Staphylococcus aureus), and abscesses.  
Infection-related safety findings in a nonhuman primate can be highly variable from study to 
study and have limited ability to accurately predict the incidence and type of infection that can be 
expected in humans, especially because nonhuman primates bear different commensal flora and 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 19 of 142 
show different sensitivity to different pathogens. Immunomodulators can increase the 
susceptibility of monkeys to potential pathogens that are endemic in nonhuman primate 
populations and usually remain clinically undetectable or are mild and self-limiting in 
immunocompetent animals. Moreover, infections associated with the gastrointestinal (GI) tract 
that result in chronic enterocolitis are a persistent and widespread colony problem in nonhuman 
primates, often multifactorial in origin.  
The nonclinical studies have highlighted the already known risk of infection linked to decreased 
muco-epidermal immunity that needs to be carefully monitored in the clinic but are unlikely to 
predict the risk of infection in humans based on dose and exposure for the aforementioned 
reasons. To date, similar findings have not been seen in studies in humans. 
Results from the embryofetal and postnatal study conducted in the Cynomolgus monkey indicate 
no effects of bimekizumab on the gestation, gestation duration, or the parturition of pregnant 
females. No bimekizumab-related effects were noted in infants at birth, during postnatal 
development, or on infant survival rate. Toxicokinetic data confirmed dose-related exposure of 
maternal animals during the pregnancy and the lactation phase, and of infants at birth and during 
the postnatal phase. 
Additional information on the nonclinical data for bimekizumab is available in the current 
version of the Investigator’s Brochure (IB). 
2.2.2 
Clinical 
2.2.2.1 
Completed studies 
In the overall bimekizumab development program, the following clinical studies in healthy 
volunteers and subjects with PSO, RA, PsA, AS, ulcerative colitis (UC), and hidradenitis 
suppurativa (HS) have been completed: 
• UP0008 was a Phase 1, first-in-human study in subjects with mild to moderate PSO.  
• RA0124 and UP0031 were 2 Phase 1, bioavailability studies in healthy subjects. 
• UP0033 was a Phase 1, open-label, multicenter, randomized, parallel-group, 3-arm, single-
dose bioequivalence study of bimekizumab injected sc either by a prefilled syringe (PFS) or 
by an auto-injector in adult healthy subjects. 
• UP0034 is a Phase 1, open-label, randomized, parallel-group, single-dose study to evaluate 
the antibody response of influenza vaccination following concomitant exposure to 
bimekizumab in adult healthy subjects. 
• UP0074 was a Phase 1, open-label, randomized, parallel-group, single-dose study to evaluate 
the PK, safety, and tolerability of bimekizumab given as 2x1mL or 1x2mL sc administration 
in healthy subjects. 
• PA0007 was a Phase 1b study in subjects with moderate to severe PsA. 
• UP0042 was a Phase 1, PK study in healthy Japanese and Caucasian subjects. 
• RA0123 was a Phase 2a study evaluating safety, PK, PD, and efficacy in subjects with 
moderate to severe RA who received bimekizumab as an add-on therapy to CZP. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 20 of 142 
• UC0011 was a Phase 2a, multinational, multicenter, subject- and Investigator-blind, 
randomized, placebo-controlled study to evaluate the efficacy, safety, tolerability, and PK of 
bimekizumab in adult subjects with moderate to severe active UC (discontinued study). 
• PS0016 was a Phase 2a study evaluating the time course of Psoriasis Area and Severity Index 
(PASI) response, safety, and PK in subjects with moderate to severe chronic plaque PSO. 
PS0018 was the corresponding Phase 2 extension study. 
• PS0018 was a Phase 2 OLE study evaluating the long-term safety, tolerability, and efficacy 
of bimekizumab in subjects who completed PS0016. 
• PS0010 was a Phase 2b, placebo-controlled, dose-ranging study evaluating safety, efficacy, 
PK, and PD in subjects with moderate to severe PSO. 
• PS0011 was a Phase 2b, multicenter, 48-week, double-blind, parallel-group, extension study 
to assess the long-term safety, tolerability, and efficacy of bimekizumab in adult subjects 
with moderate to severe chronic plaque PSO who completed PS0010. 
• PS0008 is a Phase 3, multicenter, randomized, double-blind, parallel-group, active-
comparator-controlled study to evaluate the efficacy and safety of bimekizumab in adult 
subjects with moderate to severe chronic plaque PSO. 
• PS0009 is a Phase 3 randomized, double-blind, placebo- and active comparator-controlled 
study to evaluate the efficacy and safety of bimekizumab administered sc to adult subjects 
with moderate to severe plaque PSO. 
• PS0013 is a Phase 3, multicenter, randomized withdrawal, double-blind, placebo-controlled 
study to evaluate the efficacy and safety of bimekizumab in adult subjects with moderate to 
severe chronic plaque PSO. 
• PA0008 was a Phase 2b study evaluating the efficacy and safety in subjects with active PsA. 
• AS0008 was a Phase 2b, placebo-controlled study evaluating the efficacy and safety of 
bimekizumab in subjects with active AS. 
• HS0001 was a Phase 2 study to evaluate the safety, efficacy, and PK of bimekizumab in 
subjects with moderate to severe HS. 
To evaluate treatment in subjects with PsA, bimekizumab has also been investigated in a 
Phase 1b, proof of concept, randomized, placebo-controlled, multiple dose study (PA0007). The 
primary objective of PA0007 was to assess the safety and PK of multiple dose administration of 
iv bimekizumab in subjects with PsA. Four active doses and a placebo were tested. Drug was 
administered as a loading dose at Week 1, and 2 additional doses were administered at Week 4 
and Week 7. In each treatment group, subjects received a total of 3 doses of bimekizumab, 
administered every 3 weeks as shown below: 
• 80mg loading dose followed by 40mg at Weeks 4 and 7 
• 160mg loading dose followed by 80mg at Weeks 4 and 7 
• 240mg loading dose followed by 160mg at Weeks 4 and 7 
• 560mg loading dose followed by 320mg at Weeks 4 and 7 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 21 of 142 
The results of this study demonstrated that all doses of bimekizumab were well tolerated and 
there were no unexpected clinically relevant safety findings. 
Infections (mostly nasopharyngitis) were the most commonly reported events in both the active 
treatment and the placebo group. None of the infections were considered serious or required 
treatment with antibiotics. Two subjects in the active treatment group experienced 1 local 
candida infection each (oropharyngitis and vulvovaginitis, respectively) that were nonserious and 
resolved with topical therapy. There was a potential reduction in mean neutrophil count in the 
active treatment group, although this drop was not clinically relevant and a clear relationship 
with dose or time was not evident. Some increases in liver function tests were reported, but none 
had a clear relationship to exposure to IMP. The exploratory analysis showed clinically relevant 
improvement in activity of PsA and in skin involvement in those subjects with concomitant 
active psoriatic lesions. 
PA0008 was a Phase 2b, placebo-controlled study to evaluate the efficacy, safety, tolerability, 
PK, PD, and immunogenicity of bimekizumab in subjects with active PsA. The primary 
objective of PA0008 was to assess the dose response based on the efficacy of bimekizumab 
administered sc Q4W (monthly) for 12 weeks in the treatment of subjects with active PsA. 
During the 12-week Double-Blind Period, subjects were randomized 1:1:1:1:1 (stratified by 
region and prior tumor necrosis factor [TNF] inhibitor exposure) to receive the following blinded 
IMP regimens. The enrollment of TNF inhibitor-experienced subjects was planned to be limited 
to approximately 30% of the total study population (actual enrollment was 18.9% of all subjects). 
• Placebo 
• Bimekizumab 16mg administered sc Q4W 
• Bimekizumab 160mg administered sc Q4W 
• Bimekizumab 320mg administered sc Q4W 
• Bimekizumab 320mg loading dose followed by 160mg administered sc starting at Week 4 
and Q4W thereafter  
After the 12-week Double-Blind Period, subjects entered the 36-week Dose-Blind Period. At the 
Week 12 Visit, subjects were allocated to bimekizumab treatment regimens: 160mg Q4W or 
320mg Q4W. 
The results of this study demonstrated a statistically significant dose response in the primary 
efficacy variable (ACR50 response at Week 12), and the dose response was linear for 
bimekizumab doses up to 160mg. The results of all secondary efficacy endpoints (ACR20, 
ACR70, PASI75, and PASI90 response at Week 12) were consistent with and supported the 
findings of the primary endpoint. All bimekizumab doses were associated with a greater response 
compared with placebo. 
In PA0008, all doses of bimekizumab were well tolerated, and there were no unexpected 
clinically relevant safety findings. During the overall study, the most commonly reported adverse 
events (AEs) in subjects treated with bimekizumab were nasopharyngitis (12.3%), upper 
respiratory tract infection (10.3%), respiratory tract infection (5.9%), and pharyngitis (5.4%); all 
other AEs were reported by <5.0% of subjects. There was no apparent relationship to 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 22 of 142 
bimekizumab dose with regard to the incidence of treatment-emergent adverse events (TEAEs). 
Eight subjects (3.9%) had serious adverse events (SAEs) in bimekizumab arms, and no SAE (by 
preferred term) was reported by more than 1 subject. Eight subjects (3.9%) discontinued due to a 
TEAE. 
Additional information on the clinical data for bimekizumab is available in the current version of 
the IB. 
2.2.2.2 
Ongoing studies 
The following studies of bimekizumab are ongoing:  
• PS0014 is a Phase 3, long-term extension study for eligible subjects from the Phase 3 PSO 
feeder studies to assess the safety, tolerability, and efficacy of bimekizumab. 
− DV0002 and DV0006 are multicenter, randomized, open-label studies to evaluate the 
safe and effective use of the prefilled safety syringe or the auto-injector for the sc 
self-injection of bimekizumab solution by subjects with moderate to severe PSO. 
DV0002 and DV0006 are substudies of PS0014; DV0002 is being conducted in North 
America, and DV0006 is being conducted in the EU and Japan. 
• PS0015 is a Phase 3b, randomized, double-blind, secukinumab-controlled, parallel-group 
study to evaluate the efficacy and safety of bimekizumab administered sc to subjects with 
moderate to severe chronic plaque PSO. 
• PA0009 is a Phase 2b, long-term extension study for eligible subjects from PA0008 to assess 
the safety, tolerability, and efficacy of bimekizumab. 
• PA0010 is a Phase 3, multicenter, randomized, double-blind, placebo-controlled study 
evaluating the efficacy and safety of bimekizumab in the treatment of subjects with active 
PsA. 
• PA0012 is a Phase 3, multicenter, OLE study to assess the long-term safety, tolerability, and 
efficacy of bimekizumab in the treatment of subjects with active PsA who complete PA0010 
or PA0011. 
− DV0004 is a multicenter, randomized, open-label study to evaluate the safe and effective 
use of the prefilled safety syringe or auto-injector for the sc self-injection of 
bimekizumab solution by subjects with active PsA. DV0004 is a substudy of PA0012. 
• AS0009 is a Phase 2b, long-term extension study for eligible subjects from AS0008 to assess 
the safety, tolerability, and efficacy of bimekizumab.  
• AS0010 is a Phase 3, multicenter, randomized, double-blind, placebo-controlled study 
evaluating the efficacy and safety of bimekizumab in subjects with active nonradiographic 
axial spondyloarthritis. 
• AS0011 is a Phase 3, multicenter, randomized, double-blind, placebo-controlled study 
evaluating the efficacy and safety of bimekizumab in subjects with active AS. 
• AS0014 is a Phase 3, multicenter, OLE study to assess the long-term safety, tolerability, and 
efficacy of bimekizumab in the treatment of subjects who complete AS0010 or AS0011. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 23 of 142 
• AS0013 is a Phase 2a, active-controlled study evaluating the efficacy and safety of 
bimekizumab compared with CZP in subjects with active AS. 
• HS0003 and HS0004 are Phase 3, multicenter, randomized, double-blind, placebo-controlled 
studies evaluating the efficacy and safety of bimekizumab in subjects with moderate to 
severe HS. 
• HS0005 is a Phase 3, multicenter, OLE study to assess the long-term safety, tolerability, and 
efficacy of bimekizumab in the treatment of subjects who complete HS0003 or HS0004. 
Additional information on the clinical data for bimekizumab is available in the current version of 
the IB. 
3 
STUDY OBJECTIVES 
3.1 
Primary objective 
The primary objective is to demonstrate the clinical efficacy of bimekizumab administered sc 
Q4W for 16 weeks compared with placebo in the treatment of TNFα-IR subjects with active 
PsA, as assessed by the ACR50 response. 
3.2 
Secondary objectives 
The secondary objectives of the study are as follows: 
• To assess the efficacy of bimekizumab compared with placebo  
• To assess the safety and tolerability of bimekizumab 
• To assess the impact of bimekizumab on patient-reported quality of life 
• To assess the impact of bimekizumab on skin PSO in the subgroup of affected subjects at 
Baseline 
• To assess the impact of bimekizumab on functional improvement  
3.3 
Other objectives 
Other objectives are as follows: 
• To assess the immunogenicity of bimekizumab 
• To assess the impact of bimekizumab on extra-articular disease manifestations (dactylitis, 
enthesitis) 
• To assess nail PSO in the subgroup of affected subjects at Baseline 
• To explore the exposure-response relationship of bimekizumab 
• To assess the impact of bimekizumab treatment on axial disease 
• To assess the effect of bimekizumab on gene and protein expression, and explore the 
relationship between genomic, genetic, and proteomic biomarkers and disease biology, drug 
treatment and inflammatory and immune responses (from consenting subjects who agree to 
participate in the biomarkers substudy) 
• To assess the impact of bimekizumab on social life and work productivity 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 24 of 142 
4 
STUDY VARIABLES 
4.1 
Efficacy variables 
4.1.1 
Primary efficacy variable 
The primary efficacy variable for this study is the ACR50 response at Week 16. 
4.2 
Secondary variables 
4.2.1 
Secondary efficacy variables 
The secondary efficacy variables for this study are as follows: 
• Change from Baseline in Health Assessment Questionnaire—Disability Index (HAQ-DI) at 
Week 16 
• PASI90 response at Week 4 and Week 16 in the subgroup of subjects with PSO involving at 
least 3% BSA at Baseline 
• Change from Baseline in the Short-Form 36-item Health Survey (SF-36) Physical 
Component Summary (PCS) score at Week 16 
• Minimal Disease Activity (MDA) response at Week 16 
• ACR20 response at Week 16 
• ACR70 response at Week 16 
• Proportion of subjects with an Investigator Global Assessment (IGA) score of 0 (clear) or 
1 (almost clear) AND at least a 2-grade reduction from Baseline at Week 4 and Week 16 in 
the subset of subjects with psoriatic skin lesions at Baseline  
• Change from Baseline in the Patient’s Assessment of Arthritis Pain (PtAAP) at Week 16 
• Change from Baseline in Psoriatic Arthritis Impact of Disease-12 (PsAID-12) total score at 
Week 16  
4.2.2 
Secondary safety variables 
Secondary safety variables to be assessed are as follows: 
• Incidence of TEAEs 
• Incidence of treatment-emergent SAEs 
• Treatment-emergent adverse events leading to withdrawal from IMP  
4.3 
Other variables 
4.3.1 
Other efficacy variables 
Other efficacy variables will be assessed as specified in Table 5-1 (all time points not specified 
in Section 4.1.1 or Section 4.2.1 are exploratory):  
• Time to ACR20, ACR50, and ACR70 response from Baseline (Day 1)  
• ACR20, ACR50, and ACR70 response  
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 25 of 142 
• PASI75, PASI90 and PASI100 response in the subgroup of subjects with PSO involving at 
least 3% BSA at Baseline 
• Composite endpoint composed of ACR50 and PASI90 response in subjects with PSO 
involving at least 3% BSA at Baseline 
• Composite endpoint composed of ACR50 and PASI100 response in subjects with PSO 
involving at least 3% BSA at Baseline 
• Proportion of Psoriatic Arthritis Response Criteria (PsARC) responders 
• Psoriatic Arthritis Disease Activity Score (PASDAS) categories 
• Change from Baseline in the PASDAS  
• MDA response 
• Very Low Disease Activity (VLDA) response 
• Proportion of subjects with an IGA score of 0 (clear) or 1 (almost clear) AND at least a 
2-grade reduction from Baseline in the subset of subjects with psoriatic skin lesions at 
Baseline 
• Disease Activity Index for Psoriatic Arthritis (DAPSA) score categories 
• Change from Baseline in DAPSA score 
• Change from Baseline in the Disease Activity Score-28 based on C-reactive protein 
(DAS28[CRP]) 
• Change from Baseline in all individual ACR core components: 
− SJC 
− TJC 
− HAQ-DI  
− PtAAP  
− Physician’s Global Assessment of Psoriatic Arthritis (PhGA-PsA)  
− Patient’s Global Assessment of Psoriatic Arthritis (PGA-PsA) 
− High sensitivity C-reactive protein (hs-CRP) 
• Enthesitis-free state based on the Leeds Enthesitis Index (LEI) in the subgroup of subjects 
with enthesitis at Baseline 
• Change from Baseline in the LEI in the subgroup of subjects with enthesitis at Baseline 
• Enthesitis-free state based on the Spondyloarthritis Research Consortium of Canada 
(SPARCC) index in the subgroup of subjects with enthesitis at Baseline 
• Change from Baseline in SPARCC index in the subgroup of subjects with enthesitis at 
Baseline 
• Dactylitis-free state based on the Leeds Dactylitis Index (LDI) in the subgroup of subjects 
with dactylitis at Baseline 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 26 of 142 
• Change from Baseline in the LDI in the subgroup of subjects with dactylitis at Baseline 
• Proportion of subjects with a decrease of HAQ-DI from Baseline of at least 0.35 in those 
subjects with HAQ-DI>0.35 at Baseline 
• Change from Baseline in the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) 
in the subgroup of subjects with axial involvement defined by a score of ≥4 at Baseline 
• Change from Baseline in the modified Nail Psoriasis Severity Index (mNAPSI) score in the 
subgroup of subjects with psoriatic nail disease at Baseline 
• Change from Baseline in PsAID-12 total score 
• Change from Baseline in the individual domain scores of PsAID-12 
• Proportion of subjects achieving PsAID-12 total score ≤4 
• Proportion of PsAID-12 responders (decrease from Baseline in PsAID-12 total score ≥3) in 
subjects with PsAID-12 total score >3 at Baseline 
• Change from Baseline in the Psoriatic Arthritis Quality of Life (PsAQoL) total score 
• Change from Baseline in the SF-36 PCS and SF-36 Mental Component Summary (MCS) 
scores, as well as the 8 domain scores (Physical Functioning, Role Physical, Bodily Pain, 
General Health, Vitality, Social Functioning, Role Emotional, and Mental Health) 
• Change from Baseline in Functional Assessment of Chronic Illness Therapy (FACIT)-
Fatigue subscale score 
• Proportion of FACIT-Fatigue subscale responders (subjects with a minimum clinically-
important difference for FACIT-Fatigue subscale score, defined as an increase of ≥4) in 
subjects with FACIT-Fatigue subscale score ≤48 at Baseline 
• Change from Baseline in Work Productivity and Activity Impairment Questionnaire–Specific 
Health Problem (WPAI-SHP) v2.0 adapted to PsA scores 
• Responses to the EuroQol-5D-3-Level (EQ-5D-3L) dimensions 
• Change from Baseline in EQ-5D-3L Visual Analog Scale (VAS) scores 
• Change from Baseline in Physician's Global Assessment of Arthritis (PhGA-Arthritis) 
• Change from Baseline in Patient's Global Assessment of Arthritis (PGA-Arthritis) 
4.3.2 
Other safety variables 
Other safety variables to be assessed are: 
• Change from Baseline in vital signs (blood pressure [BP], temperature, and pulse rate) 
• Standard 12-lead electrocardiogram (ECG) results 
• Change from Baseline in clinical laboratory values (hematology, biochemistry and 
urinalysis) 
• Change from Baseline in Patient Health Questionnaire-9 (PHQ-9) 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 27 of 142 
Physical examination findings considered clinically significant changes since the physical 
examination at the Screening Visit will be recorded as AEs. 
4.3.3 
Pharmacokinetic variable 
The PK variable is the plasma concentration of bimekizumab. 
4.3.4 
Pharmacogenomic variables 
Additional blood samples will be collected from subjects who consent to participate in the 
substudy at specific time points and stored at -80°C for up to 20 years. 
Genomic, genetic, epigenetic, proteins, and metabolite biomarkers may be measured to evaluate 
the relationship with response to treatment with bimekizumab, psoriatic arthritis disease biology, 
and inflammatory and immune response processes. The nature and format of these tentative 
substudy analyses will be determined when the results of the main study are made available. 
The candidate exploratory variables are the blood or blood derivative (eg, serum) concentrations 
of cytokines and chemokines of relevance to IL-17A/F signaling pathway and psoriatic arthritis 
biology. Additional variables may include but will not be limited to serum complement 
concentrations. 
4.3.5 
Immunological variables 
The immunological variables are the anti-bimekizumab antibody status and the 
treatment-emergent antibody positivity derived from anti-drug antibody assays. 
5 
STUDY DESIGN 
5.1 
Study description 
This is a Phase 3, multicenter, randomized, double-blind, placebo-controlled study to evaluate 
the efficacy and safety of bimekizumab in subjects with active PsA. To be eligible to participate 
in this study, subjects must be adults with a diagnosis of active PsA based on the CASPAR 
criteria, and have disease with TJC ≥3 and SJC ≥3, as well as an inadequate response (lack of 
efficacy after at least 3 months of therapy at an approved dose) or intolerance to treatment with 
1 or 2 TNFα inhibitors for either PsA or PSO. Detailed inclusion and exclusion criteria are 
presented in Section 6.1 and Section 6.2, respectively. 
The study will include 3 periods: a Screening Period (≥14 days to ≤35 days), a Double-Blind 
Treatment Period (16 weeks), and a Safety Follow-Up Period (20 weeks after the final dose of 
IMP). The maximum study duration per subject will be up to 37 weeks. 
Eligible subjects will be randomized 2:1 to receive 1 of 2 blinded treatments (bimekizumab 
160mg sc Q4W or placebo) and will remain on their allowable background medication. Details 
of the Treatment Period are provided in Section 5.3. 
Subjects completing Week 16 and meeting eligibility criteria are eligible for enrollment in an 
OLE study to continue to receive bimekizumab.  
A final analysis of all available data will be undertaken after all randomized subjects have 
completed 16 weeks of treatment or have been withdrawn from the study. The purpose of this 
analysis is to compare the efficacy and safety of the 2 treatment arms. For subjects who are 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 28 of 142 
ineligible for the OLE study at Week 16, a follow up analysis will be undertaken after the 
SFU Visit.  
Additional details for data monitoring in this study are provided in Section 14.8.1. A detailed 
schedule of study assessments is presented in Table 5-1 and a study schematic diagram is 
presented in Figure 5-1.  
5.2 
Screening Period/Baseline 
The Screening Period will last for a minimum duration of 14 days and a maximum duration of 
35 days and will involve obtaining laboratory data and verifying that the doses of nonsteroidal 
anti-inflammatory drugs (NSAIDs) or permitted DMARDs, if used to treat PsA, are stable. The 
Screening Period will also enable washout of any medications not permitted for use during the 
study.  
5.2.1 
Within-study rescreening/retesting requirements 
Rules for rescreening or repetition of screening tests within the study are listed below: 
• Subjects who fail to meet the eligibility criteria for PHQ-9, electronic Columbia-Suicide 
Severity Rating Scale (eC-SSRS), or the tuberculosis (TB) questionnaire are not allowed to 
be rescreened. 
The Medical Monitor must be contacted for confirmation of rescreening/retesting in all other 
cases. 
• Subjects who initially fail to meet selected eligibility criteria (eg, documented completion of 
latent tuberculosis infection [LTBI] prophylactic therapy) may be rescreened. 
• Subjects for whom eligibility assessments could not be completed as planned (eg, for 
technical reasons) within the defined Screening Period of 35 days may be rescreened.  
• Subjects with individual laboratory screening tests for which the results are exclusionary, can 
be retested.  
Of note, repetition of laboratory screening tests within the Screening Period is permitted for 
technical reasons (eg, frozen sample, expired laboratory kit) without contacting the Medical 
Monitor. 
5.3 
Treatment Period 
5.3.1 
Double-Blind Treatment Period 
During the Double-Blind Treatment Period, subjects will be randomized 2:1 (stratified by region 
and prior TNFα inhibitor exposure [inadequate response to 1 or 2 prior TNFα inhibitors, or 
intolerance to TNFα inhibitors]) to receive 1 of 2 blinded treatment regimens. 
Investigational medicinal product treatment details are provided in Section 7.2. 
Visit windows of ±3 days are allowed from the first dose at all visits through Week 16. The visit 
window is relative to the Day 1 (Baseline) Visit.  
Bimekizumab and placebo will be administered sc by unblinded study personnel at the clinical 
site. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 29 of 142 
The time between IMP doses should be ≥21 days and ≤35 days during the Double-Blind 
Treatment Period. The Double-Blind Treatment Period is 16 weeks in duration. 
Subjects discontinuing IMP during the Double-Blind Treatment Period will return for all 
scheduled visits through Week 16 and the SFU Visit (20 weeks after the final dose of IMP) as 
applicable (Section 8.4). Subjects withdrawing from the study will have an Early 
Termination (ET) Visit and a SFU Visit 20 weeks after the final dose of IMP, as applicable.  
5.4 
Safety Follow-Up Visit 
All subjects who complete the study and do not enter the extension study will undergo the 
SFU Visit 20 weeks after their final dose of IMP (see Section 8.4). 
Subjects withdrawing from the IMP during the study, will return for all scheduled visits through 
Week 16 and the SFU Visit. 
Subjects withdrawing from IMP who are not continuing for all scheduled visits, will undergo the 
ET Visit and the SFU Visit 20 weeks after their final dose of IMP. 
5.5 
Study duration per subject 
For each subject, the study will last up to 37 weeks, as follows: 
• ≥14 days to ≤35 days in the Screening Period  
• 16 weeks in the placebo-controlled, Double-Blind Treatment Period 
• An SFU Visit 20 weeks after the final dose of IMP (for subjects not entering the OLE study 
or who discontinue early, including those withdrawn from IMP) 
The end of the study is defined as the date of the last visit of the last subject in the study. 
Subjects completing Week 16 are eligible for enrollment in an OLE study to continue to receive 
bimekizumab. 
5.6 
Planned number of subjects and sites 
Approximately 390 subjects will be randomly assigned in a 2:1 ratio to the following treatment 
groups: bimekizumab 160mg sc Q4W (260 subjects) and placebo (130 subjects). The planned 
number of study sites is approximately 120.  
5.7 
Anticipated regions and countries 
This will be a multicenter, international study. Enrollment will be competitive among study sites 
and may be capped at sites.  
5.8 
Schedule of study assessments 
The schedule of study assessments is presented in Table 5-1. 
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 30 of 142 
Table 5-1: 
Schedule of study assessments 
                                                                     Visita/ 
                                                                     Week 
Protocol activity 
Screening 
(V1) 
Baseline 
(Day 1) (first 
dose) (V2 
Double-Blind Treatment Period 
(weeks after first dose) 
ET 
SFU b 
3/ 
(4) 
4/ 
(8) 
5/ 
(12) 
6/ 
(16) 
Written Informed consent 
X 
 
 
 
 
 
 
 
Inclusion/exclusion 
X 
X 
 
 
 
 
 
 
Demographic data c 
X 
 
 
 
 
 
 
 
Psoriatic arthritis history 
X 
 
 
 
 
 
 
 
Significant past medical history and concomitant 
diseases 
X 
X d 
 
 
 
 
 
 
Prior medication 
X 
 
 
 
 
 
 
 
Concomitant medication 
X 
X 
X 
X 
X 
X 
X 
X 
PHQ-9 
X 
X 
X 
X 
X 
X 
X 
X 
eC-SSRS 
X 
X 
X 
X 
X 
X 
X 
X 
Height e 
 
X 
 
 
 
 
 
 
Weight e 
 
X 
 
 
 
X 
X 
X 
Vital signs f 
X 
X  
X 
X 
X 
X 
X 
X 
ECG by central reader 
X 
 
 
 
 
X 
X 
X 
Hematology/biochemistry g 
X 
X 
X 
X 
X 
X 
X 
X 
hs-CRP h 
X 
X 
X 
X 
X 
X 
X 
X 
Urinalysis 
X 
X 
X 
X 
X 
X 
X 
X 
Pregnancy testing i 
X 
X 
X 
X 
X 
X 
X 
X 
Urine drug screen 
X 
 
 
 
 
 
 
 
Hepatitis B and C testing 
X 
 
 
 
 
 
 
 
HIV testing 
X 
 
 
 
 
 
 
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 31 of 142 
Table 5-1: 
Schedule of study assessments 
                                                                     Visita/ 
                                                                     Week 
Protocol activity 
Screening 
(V1) 
Baseline 
(Day 1) (first 
dose) (V2 
Double-Blind Treatment Period 
(weeks after first dose) 
ET 
SFU b 
3/ 
(4) 
4/ 
(8) 
5/ 
(12) 
6/ 
(16) 
HLA-B27 
 
X 
 
 
 
 
 
 
RF and anti-CCP antibodies 
X 
 
 
 
 
 
 
 
Blood sample for bimekizumab plasma concentrations j 
 
X 
X 
X 
X 
X 
X 
X 
Anti-bimekizumab antibody detection j 
 
X 
X 
X 
X 
X 
X 
X 
Serum and plasma blood samples for exploratory 
biomarkersj 
 
X 
 
 
 
X 
 
 
RNA blood samples for exploratory biomarkers j 
 
X 
 
 
 
X 
 
 
Blood samples for genetic/epigenetic analysis j 
 
X 
 
 
 
X 
 
 
IGRA tuberculosis test 
X 
 
 
 
X 
 
 
 
Tuberculosis questionnaire 
X 
X 
 
 
X 
X 
X 
X 
Physical examination k 
X 
X 
 
 
 
X 
X 
X 
BSA affected by PSO l 
X 
X 
X 
X 
X 
X 
X 
X 
PASI m 
X 
X 
X 
X 
X 
X 
X 
X 
IGAm 
X 
X 
X 
X 
X 
X 
X 
X 
TJC and SJC 
X 
X 
X 
X 
X 
X 
X 
X 
HAQ-DI 
 
X 
X 
X 
X 
X 
X 
X 
PtAAP 
 
X 
X 
X 
X 
X 
X 
X 
PhGA-PsA 
 
X 
X 
X 
X 
X 
X 
X 
PhGA-Arthritis 
 
X 
X 
X 
X 
X 
X 
X 
PGA-PsA 
 
X 
X 
X 
X 
X 
X 
X 
PGA-Arthritis 
 
X 
X 
X 
X 
X 
X 
X 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 32 of 142 
Table 5-1: 
Schedule of study assessments 
                                                                     Visita/ 
                                                                     Week 
Protocol activity 
Screening 
(V1) 
Baseline 
(Day 1) (first 
dose) (V2 
Double-Blind Treatment Period 
(weeks after first dose) 
ET 
SFU b 
3/ 
(4) 
4/ 
(8) 
5/ 
(12) 
6/ 
(16) 
BASDAI 
 
X 
X 
X 
X 
X 
X 
X 
mNAPSIn 
 
X 
X 
X 
X 
X 
X 
 
LEI 
 
X 
X 
X 
X 
X 
X 
X 
SPARCC 
 
X 
X 
X 
X 
X 
X 
X 
LDI o 
 
X 
X 
X 
X 
X 
X 
X 
PsAQoL 
 
X 
X 
 
X 
X 
X 
X 
PsAID-12 
 
X 
X 
 
X 
X 
X 
 
FACIT-Fatigue subscale 
 
X 
X 
 
X 
X 
X 
 
SF-36 
 
X 
X 
 
X 
X 
X 
X 
EQ-5D-3L 
 
X 
X 
 
X 
X 
X 
 
WPAI-SHP 
 
X 
 
 
X 
X 
X 
 
Chest x-ray p 
X 
 
 
 
 
 
 
 
X-ray of hands and feet q 
X 
 
 
 
 
 
 
 
Adverse events r 
X 
X 
X 
X 
X 
X 
X 
X 
IXRS s 
X 
X 
X 
X 
X 
X 
X 
X 
IMP administrationt 
 
X 
X 
X 
X 
 
 
 
BASDAI=Bath Ankylosing Spondylitis Disease Index; BP=blood pressure; BSA=body surface area; CASPAR=Classification Criteria for Psoriatic 
Arthritis; CCP=cyclic citrullinated peptide; ECG=electrocardiogram; eC-SSRS=electronic Columbia-Suicide Severity Rating Scale; 
EQ-5D-3L=EuroQol-5-Dimensions-3L; ET=Early Termination; FACIT=Functional Assessment of Chronic Illness Therapy; HAQ-DI=Health 
Assessment Questionnaire—Disability Index; HDL=high density lipoprotein; HIV=human immunodeficiency virus; HLA-B27=human leukocyte 
antigen B27; hs-CRP=C-reactive protein; IGA=Investigator’s Global Assessment; IGRA=interferon gamma release assay; IMP=investigational 
medicinal product; IXRS=interactive voice or web response system; LDI=Leeds Dactylitis Index; LDL=low density lipoprotein; LEI=Leeds Enthesitis 
Index; OLE=open-label extension; mNAPSI=modified Nail Psoriasis Severity Index; PASI=Psoriasis Area and Severity Index; PGA-arthritis=Patient’s 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 33 of 142 
Table 5-1: 
Schedule of study assessments 
                                                                     Visita/ 
                                                                     Week 
Protocol activity 
Screening 
(V1) 
Baseline 
(Day 1) (first 
dose) (V2 
Double-Blind Treatment Period 
(weeks after first dose) 
ET 
SFU b 
3/ 
(4) 
4/ 
(8) 
5/ 
(12) 
6/ 
(16) 
Global Assessment of Arthritis; PGA-PsA=Patient’s Global Assessment of Psoriatic Arthritis; PhGA-arthritis=Physician’s Global Assessment of 
Arthritis; PhGA-PsA=Physician’s Global Assessment of Psoriatic Arthritis; PHQ-9=Patient Health Questionnaire-9; PsA=psoriatic arthritis; 
PsAID=Psoriatic Arthritis Impact of Disease; PsAQoL=Psoriatic Arthritis Quality of Life; PSO=psoriasis; PtAAP=Patient’s Assessment of Arthritis 
Pain; Q4W=every 4 weeks; RF=rheumatoid factor; RNA=ribonucleic acid; SF-36=Short-Form 36-item Health Survey; SFU=Safety Follow-Up; 
SJC=swollen joint count; SPARCC= Spondyloarthritis Research Consortium of Canada; TB=tuberculosis; TJC=tender joint count; V=visit; WPAI-
SHP=Work Productivity and Activity Impairment Questionnaire – Specific Health Problem 
a Visit windows of ±3 days from the first dose at all visits through Week 16. The time between IMP doses should be ≥21 days and ≤35 days during 
the Double-Blind Treatment Period. For the SFU Visit, the visit should occur no more than 3 days prior to the scheduled visit date and within 7 
days after the scheduled visit date (-3 days/+7 days). 
b Safety Follow-Up Visit occurs 20 weeks after the final dose of IMP for all subjects who complete the study and do not enter the OLE study or who 
discontinue early, including those withdrawn from IMP.  
c A complete history of lifestyle (alcohol, drug and nicotine consumption at the time of screening) and infections (fungal skin infections within 12 
months prior to Screening). 
d Confirm there are no significant changes in medical history that would exclude the subject based on the exclusion criteria. 
e The Investigator or designee will measure the height of the subject with shoes removed in meters and the weight of the subject in kilograms. 
f Collect vital signs (pulse rate, BP, and temperature) prior to IMP administration and then approximately at 30 minutes after administration and 
1 hour after administration at Baseline. At all other applicable visits, vital signs will be collected once prior to IMP administration. All other 
procedures are done prior to dosing. 
g Biochemistry testing will include triglycerides, cholesterol, HDL cholesterol, and LDL cholesterol at Baseline, Week 16, and at the ET. 
h After Screening, the hs-CRP data will not be sent to the Investigator to protect the blinded nature of the treatment assignments. 
i Pregnancy testing will consist of serum testing at Screening for all women of childbearing potential. The pregnancy test will be urine at all other 
visits. 
j At dosing visits, all blood samples are taken prior to dosing. Blood samples for bimekizumab and anti-bimekizumab antibody detection will be 
processed as per instructions in the laboratory manual. 
k Includes evaluation of signs and symptoms of active TB and risk for exposure to TB.  
l Any subject with PSO lesions at Baseline will have a BSA-PSO assessment (Section 9.8.1) at each scheduled visit. 
m Only subjects with a BSA of ≥3% at Baseline will be required to have the PASI and IGA assessed at visits post Baseline (Day 1). 
n Only for subjects who have nail PSO at Baseline. 
o Circumference measured in millimeters. The LDI assessment of dactylitis will be obtained for all subjects at all visits after the Screening Visit.  
p If a subject has had a radiograph of the chest within 3 months prior to the Screening Visit, it may be used as the Screening chest x-ray.  
q The x-ray at Screening will be used for CASPAR classification (for inclusion). 
r Adverse events are to be collected beginning at the signing of the Informed Consent form. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 34 of 142 
Table 5-1: 
Schedule of study assessments 
                                                                     Visita/ 
                                                                     Week 
Protocol activity 
Screening 
(V1) 
Baseline 
(Day 1) (first 
dose) (V2 
Double-Blind Treatment Period 
(weeks after first dose) 
ET 
SFU b 
3/ 
(4) 
4/ 
(8) 
5/ 
(12) 
6/ 
(16) 
s The IXRS will be used to register subjects at Screening, to randomize eligible subjects to treatment groups at Day 1 (Baseline) and to register visits. 
t For the full details of bimekizumab and placebo dosing, see Section 7.2.  
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 35 of 142 
5.9 
Schematic diagram 
The study schematic PA0011 is presented in Figure 5-1. 
Figure 5-1: Study schematic diagram 
 
ACR50=American College of Rheumatology 50% response criteria; Q4W=every 4 weeks; SFU=Safety Follow-Up; 
sc=subcutaneous; W=week 
5.10 
Rationale for study design and selection of dose 
Bimekizumab doses of 16mg, 160mg, 160mg with an initial 320mg dose, and 320mg were 
evaluated in PA0008, a Phase 2b multicenter, randomized, double-blind, placebo-controlled, 
parallel group, dose-ranging study. In this study, doses up to 320mg were well tolerated by 
subjects and found to have acceptable safety profile.  
PA0011 will evaluate the efficacy and safety of bimekizumab 160mg sc Q4W in adult subjects 
with active PsA. The dose was selected based on the data from Phase 2b study. In PA0008, both 
ACR50 and PASI90 responder rates saturate at bimekizumab 160mg Q4W, further increase in 
dose does not provide a significant benefit on either ACR50 or PASI90 responder rates. An 
exposure-response analysis was performed on both endpoints which also indicated that 
bimekizumab 160mg Q4W is the optimal dose for these subjects. 
There were no dose-related safety concerns or changes in laboratory values in the preliminary 
data review up to 48 weeks that preclude the use of any of the tested doses in PA0008 for the 
Phase 3 program in PsA. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 36 of 142 
6 
SELECTION AND WITHDRAWAL OF SUBJECTS 
6.1 
Inclusion criteria 
To be eligible to participate in this study, all of the following criteria must be met at Screening 
and be reconfirmed at the Baseline Visit: 
1a. An Institutional Review Board (IRB)/Independent Ethics Committee (IEC) approved written 
Informed Consent form (ICF) is signed and dated by the subject.  
2a. Subject is considered reliable and capable of adhering to the protocol (eg, able to understand 
and complete diaries), visit schedule, or medication intake according to the judgment of the 
Investigator. 
3. Subject is male or female at least 18 years of age. 
4. Female subjects must be: 
− postmenopausal (menopause is defined as 12 consecutive months of amenorrhea, for 
which there is no other obvious pathological or physiological cause),  
− permanently sterilized (eg, tubal occlusion, hysterectomy, bilateral salpingectomy),  
− or, if of childbearing potential (and engaged in sexual activity that could result in 
procreation), must be willing to use a highly effective method of contraception 
throughout the duration of the study until 20 weeks after last administration of IMP, and 
have a negative pregnancy test at Screening and immediately prior to the first dose.  
The following methods are considered highly effective when used consistently and correctly: 
− combined (estrogen and progestogen) hormonal contraception associated with inhibition 
of ovulation (oral, intravaginal, or transdermal)  
− progestogen-only hormonal contraception associated with inhibition of ovulation (oral, 
injectable, or implantable) 
− intrauterine device  
− intrauterine hormone-releasing system 
− vasectomized partner  
− Abstinence as a form of birth control is generally not allowed in the study unless 
abstinence is in accordance with a subject’s preferred and common lifestyle. Study 
personnel must confirm the continued use of abstinence is still in accordance with the 
subject’s lifestyle at regular intervals during the study.  
5. Subject has a documented diagnosis of adult-onset PsA classified and meets the CASPAR 
classification criteria (Table 18-1) for at least 6 months prior to Screening with active PsA 
and must have at Baseline TJC ≥3 out of 68 and SJC ≥3 out of 66 (dactylitis of a digit counts 
as 1 joint each). 
6. Subject must be negative for rheumatoid factor and anti-cyclic citrullinated peptide (CCP) 
antibodies. 
7. Subject must have at least 1 active psoriatic lesion(s) and/or a documented history of PSO. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 37 of 142 
8. Subject has a history of inadequate response (lack of efficacy after at least 3 months of 
therapy at an approved dose) or intolerance to treatment with 1 or 2 TNF(α) inhibitors for 
either PsA or PSO. 
9. Subjects who are regularly taking NSAIDs/COX-2 inhibitors/mild opioid analgesics as part 
of their PsA therapy are required to be on a stable dose/dose regimen for at least 14 days 
before Baseline and should remain on a stable dose through the duration of the study. 
10. Subjects taking oral corticosteroids must be on an average daily dose of ≤10mg/day 
prednisone or equivalent for at least 14 days before Baseline and should remain on a stable 
dose through the duration of the study. 
11. Subjects taking MTX (≤25mg/week) are allowed to continue their medication if started at 
least 12 weeks prior to Baseline, with a stable dose for at least 8 weeks before randomization. 
Dose, dosing schedule and route of administration (oral or sc) should remain stable through 
the duration of the study. It is strongly recommended that subjects taking MTX are also 
taking folic acid supplementation. 
12. Subjects taking LEF (≤20mg/day or an average of 20mg/day if not dosed daily) are allowed 
to continue their medication if started at least 12 weeks prior to Baseline, with a stable dose 
for at least 8 weeks before randomization. Dose and dosing schedule should remain stable 
through the duration of the study. 
13. Subjects taking SSZ (up to 3g/day for arthritis or 4/g per day if in accordance with local 
standard of care), HCQ (up to 400mg/day), or apremilast (up to 60mg/day and dosed as per 
local label) are allowed to continue their medication if started 8 weeks prior Baseline, with a 
stable dose for at least 4 weeks before randomization. 
6.2 
Exclusion criteria 
Subjects are not permitted to enroll in the study if any of the following criteria are met: 
1. Female subjects who are breastfeeding, pregnant, or plan to become pregnant during the 
study or within 20 weeks following final dose of IMP.  
2. Subjects with current or prior exposure to any biologics except TNF inhibitors for the 
treatment of PsA or PSO, including participation in a bimekizumab clinical study who 
received at least 1 dose of IMP (including placebo). 
3. Subject previously participated in another study of a medication (systemic) under 
investigation. Subject must be washed out of the medication for 12 weeks or at least 
5 half-lives prior to the Baseline Visit, whichever is greater, or is currently participating in 
another study of a medication (systemic) under investigation.  
4. Subject previously participated in another study of a medical device under investigation 
within the 4 weeks prior to the Screening Visit or is currently participating in another study 
of a medical device under investigation. 
5. Subject has a known hypersensitivity to any excipients of bimekizumab. 
6. Subject is taking or has taken prohibited PsA or PSO medications without meeting the 
mandatory wash-out period relative to the Baseline Visit (Table 7‒1 and Table 7-2). 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 38 of 142 
7. Subject has an active infection or history of infections as follows: 
− Any active infection (except common cold) within 14 days prior to Baseline. 
− A serious infection, defined as requiring hospitalization or iv anti-infectives within 
2 months prior to Baseline. 
− A history of opportunistic, recurrent or chronic infections that, in the opinion of the 
Investigator, might cause this study to be detrimental to the subject. Opportunistic 
infections are infections caused by uncommon pathogens (eg, pneumocystis jirovicii, 
cryptococcosis) or unusually severe infections caused by common pathogens 
(eg, cytomegalovirus, herpes zoster).  
8. Subject has concurrent acute or chronic viral hepatitis B or C or human immunodeficiency 
virus (HIV) infection. Subjects who have evidence of or tested positive for hepatitis B or 
hepatitis C are excluded.  
A positive test for the hepatitis B virus is defined as:  
• positive for hepatitis B surface antigen; or,  
• positive for anti-hepatitis B core antibody  
A positive test for the hepatitis C virus (HCV) is defined as:  
• positive for hepatitis C antibody (anti-HCV antibody), and  
• positive via a confirmatory test for HCV (for example, HCV polymerase chain reaction) 
9. Subject has received any live (includes attenuated) vaccination within the 8 weeks prior to 
the Baseline (eg, inactivated influenza and pneumococcal vaccines are allowed but nasal 
influenza vaccination is not permitted). 
10. Subject has received Bacillus Calmette-Guerin (BCG) vaccinations within 1 year prior to the 
Baseline Visit. 
11. Subject has known tuberculosis (TB) infection, is at high risk of acquiring TB infection, or 
has current or history of nontuberculous mycobacterium (NTMB) infection. A subject with 
latent tuberculosis (LTB) (a positive interferon gamma release assay [IGRA] and diagnosis 
confirmed by TB specialist) may be rescreened once and enrolled after receiving at least 
4 weeks of appropriate LTB infection (LTBI) therapy and if no evidence of therapy-related 
hepatotoxicity has occurred prior to the first injection (alanine aminotransferase 
[ALT]/aspartate aminotransferase [AST] remain ≤3 times upper limit of normal [ULN]).  
Subject has a past history of active TB involving any organ system unless adequately treated 
according to World Health Organization/Center for Disease Control and Prevention 
therapeutic guidance and proven to be fully recovered upon consult with a TB specialist.  
Refer to Section 12.3.6 for details on determining full TB exclusion criteria. 
12. Subject has a history of a lymphoproliferative disorder including lymphoma and/or current 
signs and symptoms suggestive of lymphoproliferative disease. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 39 of 142 
13. Subject has a diagnosis of inflammatory conditions other than PSO or PsA including but not 
limited to RA, sarcoidosis, systemic lupus erythematosus, and reactive arthritis. Subjects 
with a diagnosis of Crohn’s disease, ulcerative colitis, or other inflammatory bowel disease 
(IBD) are allowed as long as they have no active symptomatic disease at Screening or 
Baseline. 
14. Subject had acute anterior uveitis within 6 weeks of Baseline. 
15. Subjects with fibromyalgia or osteoarthritis symptoms that, in the Investigator’s opinion, 
would have potential to interfere with efficacy assessments. 
16. Subject has any active malignancy or history of malignancy within 5 years prior to the 
Screening Visit EXCEPT treated and considered cured cutaneous squamous or basal cell 
carcinoma, or in situ cervical cancer. 
17. Subject has a form of PSO other than chronic plaque-type (eg, pustular, erythrodermic and 
guttate PSO, or drug-induced PSO). 
18. Subject has had major surgery (including joint surgery) within the 3 months prior to 
Baseline, or planned surgery within 6 months after entering the study. 
19. Subject has any systemic disease (cardiovascular, neurological, renal, liver, metabolic, GI, 
hematological, immunological, etc) considered by the Investigator to be uncontrolled, 
unstable or likely to progress to a clinically significant degree during the course of the study. 
20. Subject has had myocardial infarction or stroke within the 6 months prior to the Screening 
Visit. 
21. Subject has laboratory abnormalities at Screening, including any of the following:  
a. ≥3x ULN of any of the following: ALT, AST, alkaline phosphatase (ALP); or >ULN 
total bilirubin (≥1.5xULN total bilirubin if known Gilbert’s syndrome) 
b. White blood cell count (WBC) <3.0x103/μL  
c. Absolute neutrophil count <1.5x103/μL 
d. Lymphocyte count <500 cells/μL 
e. Hemoglobin <8.5g/dL 
f. Creatinine >2mg/dL 
g. Any other laboratory abnormality, which, in the opinion of the Investigator, will prevent 
the subject from completing the study or will interfere with the interpretation of the study 
results.  
Individual screening tests for which the results are in error, borderline, or indeterminate for 
inclusion in the study, can be repeated once for confirmation during the Screening Period. 
Upon retesting, subjects whose results remain outside this threshold should not be 
randomized. 
22. Subject has any other condition including medical or psychiatric which, in the Investigator's 
judgment, would make the subject unsuitable for inclusion in the study. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 40 of 142 
23. Presence of active suicidal ideation, or positive suicide behavior using the “Screening” 
version of the electronic Columbia-Suicide Severity Rating Scale (eC-SSRS) with either of 
the following criteria: 
− Subject has a history of a suicide attempt within the 5 years prior to the Screening Visit. 
Subjects with a history of a suicide attempt more than 5 years ago should be evaluated by 
a mental healthcare professional (eg, locally licensed psychiatrist, psychologist, or 
master’s level therapist) before enrolling into the study. 
− Subject has suicidal ideation in the past month prior to the Screening Visit as indicated by 
a positive response (“Yes”) to either Question 4 or Question 5 of the “Screening” version 
of the eC-SSRS. 
24. Subject has presence of moderately severe major depression, or severe major depression, 
indicated by a score ≥15 using the screening PHQ-9. Medication used to treat depression 
should be stable for 8 weeks prior to Baseline. 
25. Subjects taking PsA medications other than MTX, SSZ, apremilast, HCQ, LEF, 
NSAIDs/COX-2 inhibitors, and oral corticosteroids as outlined in the Inclusion criteria 
(Section 6.1). Stable doses/regimens of analgesics are also permitted. 
26. Subject has a history of chronic alcohol or drug abuse within 6 months prior to Screening 
evaluated by the Investigator based on medical history, site interview, and results of the 
specified urine drug screen.   
27. Subject is a member of Investigator site personnel directly affiliated with this study and/or 
their immediate families. Immediate family is defined as a spouse, parent, child, or sibling, 
whether biological or legally adopted. 
28. Subject is a UCB employee or is an employee of third-party organizations involved in the 
study. 
6.3 
Withdrawal criteria 
Subjects are free to withdraw from the study at any time, without prejudice to their continued 
care. Subjects who withdraw from the study should complete the Early Termination Visit (see 
Section 8.3).  
Subjects should be withdrawn from the study and will be asked to come back for the SFU Visit 
20 weeks after final dose of IMP if the subject withdraws his/her consent. 
Subjects should be withdrawn from IMP and will be asked to come back for all scheduled visits 
(up to Week 16) and the SFU Visit 20 weeks after the final dose of IMP if any of the following 
events occur: 
1. The Sponsor or a regulatory agency requests withdrawal of the subject. 
2. Subject develops an illness that, in the opinion of the Investigator, would interfere with 
his/her continued participation, if the risk of continuing with IMP outweighs the potential 
benefit. 
3. Subject is noncompliant with the study procedures or medications, which may present a risk 
to the safety of the subject, in the opinion of the Investigator. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 41 of 142 
4. Subject uses prohibited concomitant medications, as defined in Section 7.8.2, that may 
present a risk to the safety of the subject in the opinion of the Investigator and the Medical 
Monitor. 
5. Subject has a clinical laboratory value meeting any of the following criteria: 
a. Hepatotoxicity as described in Section 6.3.1. 
b. A laboratory value meeting any of the following criteria: 
− Absolute neutrophil count <1.0x103/μL 
− Absolute lymphocyte count <0.2x103/μL 
Subjects may remain on the IMP if the result is transient. A retest is required within 
1 to 2 weeks at a scheduled or unscheduled visit. If the repeat absolute neutrophil count or 
absolute lymphocyte count is still below the allowable values, the subject must be withdrawn 
from the IMP. If the repeat absolute neutrophil count or absolute lymphocyte count is above 
the allowable values, the subject may continue to receive IMP. 
6. The subject experiences a severe AE, an SAE, or a clinically significant change in a 
laboratory value occurs that, in the opinion of the Investigator, merits the discontinuation of 
the IMP and appropriate measures being taken. 
7. There is confirmation of a pregnancy during the study, as evidenced by a positive pregnancy 
test (see Section 12.1.4 for more information regarding pregnancies). 
8. Subject develops erythrodermic, guttate or generalized pustular form of PSO. 
9. A subject considered as having either a suspected new LTB infection or who develops active 
TB or NTMB infection during the study (including but not limited to, conversion 
demonstrated by IGRA or other diagnostic means) must be immediately discontinued from 
IMP, an ET Visit must be scheduled as soon as possible, but not later than the next regular 
visit. 
The subject must be permanently withdrawn if further examinations result in a diagnosis of 
active TB, or if the subject is diagnosed with LTB infection with no initiation of prophylactic 
treatment, prematurely discontinues prophylactic treatment, or, in the opinion of the 
Investigator or Sponsor, is noncompliant with prophylactic TB therapy. 
Confirmed active TB is an SAE and must be captured in the electronic Case Report Form 
(eCRF) in the SAE Report Form section. As with all SAEs, periodic follow-up reports should 
be completed as per protocol requirements until such time as the TB infection resolves. 
Additional information on TB policies is provided in Section 12.3.6. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 42 of 142 
10. Subjects with newly diagnosed IBD or with IBD flares during the study must: 
− Be referred, as appropriate, to a health care professional treating IBD, such as a 
gastroenterologist 
− Discontinue IMP and be followed-up until resolution of active IBD symptoms 
If IBD flares increase in severity or frequency during the study, the Investigator should use 
clinical judgment in deciding whether the subject should continue on IMP and contact the 
Medical Monitor and UCB study physician to confirm the subject's suitability for continued 
participation in the study. 
11. Subjects must be referred immediately to a mental health care professional and may be 
withdrawn from the study based upon the Investigator’s judgment of benefit/risk for: 
− Active suicidal ideation as indicated by a positive response (“Yes”) to Questions 4 of the 
“Since Last Visit” version of the eC-SSRS 
− Moderately severe major depression as indicated by a PHQ-9 score of 15 to 19 if this 
represents an increase of 3 points compared to last visit 
The mental health consultation must be recorded in the subject’s source documentation.  
12. Subjects must be referred immediately to a mental healthcare professional and must be 
withdrawn in case of: 
− Active suicidal ideation as indicated by a positive response (“Yes”) to Question 5 of the 
“Since Last Visit” version of the eC-SSRS. 
− Any suicidal behavior since the last visit.  
− Severe major depression as indicated by a PHQ-9 score ≥20. 
The mental health consultation must be recorded in the subject’s source documentation. 
13. Any subject who develops a clinically important infection or recurrent infections not 
responsive to standard therapy during the study must discontinue IMP until resolution of the 
infection. The Investigator should use clinical judgement in deciding whether the subject 
should restart IMP and contact the Medical Monitor and UCB study physician to confirm the 
subject’s suitability for continued participation in the study. 
Investigators should contact the Medical Monitor, whenever possible, to discuss the withdrawal 
of a subject from IMP or from the study in advance. 
Subjects withdrawing from the study who are not continuing for all scheduled visits, will 
undergo the ET Visit and the SFU Visit 20 weeks after their final dose of IMP. 
Investigators should attempt to obtain information on subjects in the case of withdrawal or 
discontinuation. For subjects considered as lost to follow-up, the Investigator should make an 
effort (at least 1 phone call and 1 written message to the subject), and document his/her effort 
(date and summary of the phone call and copy of the written message in the source documents), 
to complete the final evaluation. All results of these evaluations and observations, together with a 
narrative description of the reason(s) for removing the subject, must be recorded in the source 
documents. The eCRF must document the primary reason for withdrawal or discontinuation. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 43 of 142 
6.3.1 
Potential drug-induced liver injury IMP discontinuation criteria 
Subjects with potential drug-induced liver injury (PDILI) must be assessed to determine if IMP 
must be discontinued. In addition, all concomitant medications and herbal supplements that are 
not medically necessary should also be discontinued.  
The PDILI criteria below require immediate discontinuation of IMP:  
• Subjects with either of the following: 
− ALT or AST ≥8xULN  
− ALT or AST ≥3xULN and coexisting total bilirubin ≥2xULN  
• - Subjects with ALT or AST ≥3xULN who exhibit temporally associated symptoms of 
hepatitis or hypersensitivity. Hepatitis symptoms include fatigue, nausea, vomiting, right 
upper quadrant pain or tenderness. Hypersensitivity symptoms include fever (without clear 
alternative cause), rash, or eosinophilia (ie, >5%). 
If a nondrug-related cause for the symptoms can be confirmed, these subjects may resume IMP 
administration after discussion with the responsible UCB physician, but only when the 
requirements for rechallenge with IMP as provided in Section 12.2.1.2.1 are followed. 
The PDILI criterion below allows for subjects to continue on IMP at the discretion of the 
Investigator.  
• Subjects with ALT or AST ≥5xULN and <8xULN, total bilirubin <2xULN, and no 
eosinophilia (ie, ≤5%), with no fever, rash, or symptoms of hepatitis (eg, fatigue, nausea, 
vomiting, right upper quadrant pain or tenderness).  
Evaluation of PDILI must be initiated as described in Section 12.2.1 with repeat tests performed 
in 2 weeks. Upon retest, if ALT or AST values have reduced to <5xULN, the subject can 
continue with the study. However, if ALT or AST remains ≥5xULN <8xULN after retest, IMP 
should be temporarily withheld and subject should undergo a repeat test in 2 weeks. The subject 
will continue to be monitored at least twice per week until values normalize, stabilize, or return 
to within baseline values. If ALT or AST values remain ≥5xULN even after the second retest, 
then the subject should be permanently withdrawn from the study and should be followed for 
possible PDILI.  
If subjects are unable to comply with the applicable monitoring schedule, IMP must be 
discontinued immediately. 
Investigators should attempt to obtain information on subjects in the case of IMP discontinuation 
to complete the final evaluation. Subjects with PDILI should not be withdrawn from the study 
until investigation and monitoring are complete. All results of these evaluations and 
observations, as well as the reason(s) for IMP discontinuation and subject withdrawal (if 
applicable), must be recorded in the source documents. The eCRF must document the primary 
reason for IMP discontinuation. 
7 
STUDY TREATMENTS 
7.1 
Description of investigational medicinal products 
The IMPs used in this study are bimekizumab and placebo. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 44 of 142 
 
 
 
Placebo will be supplied as 0.9% sodium chloride aqueous solution (physiological saline, 
preservative-free) of pharmacopoeia (U.S. Pharmacopeia/European Pharmacopeia) quality in a 
1mL PFS for sc injection. 
Further details of the IMPs and their specification will be provided in the IMP Handling Manual. 
7.2 
Treatments to be administered 
Unblinded study staff will be responsible for preparation of the clinical study material, including 
recording the administration information on source documents, and administration of the IMP as 
sc injections. The unblinded personnel will not be involved in the study in any way other than 
assuring the medication is taken from the correct kit and administering the IMP to the subjects. 
Suitable areas for sc injections are the abdominal wall, thigh, or upper outer arm without 
massage. On Day 1 (Baseline) one 160mg injection or one injection of placebo will be 
administered. Injection sites should be rotated between visits and injections should not be given 
in areas where the skin is tender, bruised, red, or hard. 
An IMP Handling Manual will be provided to each site containing instructions regarding drug 
preparation and dosing. 
Double-Blind Treatment Period dosing 
During the Double-Blind Treatment Period, subjects will be randomized 2:1 to receive the 
following blinded IMP regimens: bimekizumab 160mg sc Q4W or placebo. 
All subjects will receive 1 injection sc on Day 1 (Baseline) and 1 injection sc Q4W based on the 
following dosing scheme: 
• Subjects randomized to receive bimekizumab will receive bimekizumab 160mg sc Q4W 
starting on Day 1 (Baseline). 
• Subjects randomized to receive placebo will receive placebo injections sc Q4W starting on 
Day 1 (Baseline).   
7.3 
Packaging 
The IMPs are manufactured, packaged, and labeled according to Good Manufacturing Practice 
(GMP) guidelines and applicable laws or regulations. Investigational medicinal products will be 
suitably packaged in such a way as to protect the IMPs from deterioration during transport and 
storage. 
7.4 
Labeling 
Clinical drug supplies will be labeled in accordance with the current International Council for 
Harmonisation (ICH) guidelines on Good Clinical Practice (GCP) and GMP and will include any 
locally required statements. If necessary, labels will be translated into the local language. 
7.5 
Handling and storage requirements 
Investigational Medicinal Products must be stored under refrigerated conditions (2ºC to 8ºC) 
protected from light. The IMPs must not be frozen. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 45 of 142 
The Investigator (or designee) is responsible for the safe and proper storage of IMP at the site. 
Investigational medicinal product stored by the Investigator is to be kept in a secured area with 
limited access according to the storage conditions mentioned on the label. 
Appropriate storage conditions must be ensured either by controlling the temperature (eg, room, 
refrigeration unit) or by completion of a temperature log in accordance with local requirements 
on a regular basis, showing actual and minimum/maximum temperatures reached over the time 
interval.  
In case an out-of-range temperature is noted, it must be immediately reported as per instructions 
contained in the IMP Handling Manual. 
7.6 
Drug accountability 
A Drug Accountability form will be used to record IMP dispensing and return information on a 
by-subject basis and will serve as source documentation during the course of the study. Details of 
any IMP lost, damaged (due to breakage or wastage), not used, partially used, disposed of at the 
study site, or returned to the Sponsor or designee must also be recorded on the appropriate forms. 
All supplies and pharmacy documentation must be made available throughout the study for UCB 
(or designee) to review. 
The packaging identifies each kit by a unique number that does not correlate to the contents and, 
therefore, does not unblind study site staff. Unblinded study staff will be responsible for 
preparation (eg, breaking tamper proof sticker on kit) of the clinical study material, including 
recording the administration information in the source document. 
The Investigator (or designee) is responsible for retaining all used, unused, and partially used 
containers of IMP until returned or destroyed. 
The Investigator must assign some of the Investigator’s duties for drug accountability at the 
study site to an appropriate pharmacist/designee. 
The Investigator must ensure that the IMP is used only in accordance with the protocol. 
Periodically, and/or after completion of the clinical phase of the study, all used (including empty 
containers)/partially used, unused, damaged, and/or expired IMP must be reconciled and either 
destroyed at the site according to local laws, regulations, and UCB standard operating procedures 
(SOPs), or returned to UCB (or designee). Investigational medicinal product intended for the 
study cannot be used for any other purpose than that described in this protocol. 
7.7 
Procedures for monitoring subject compliance 
Bimekizumab and placebo will be administered in the clinic and compliance will be determined 
at the visit by study personnel. Drug accountability must be recorded on the Drug Accountability 
form. 
7.8 
Concomitant medications/treatments 
All concomitant medications, including over-the-counter products, herbal, traditional remedies, 
vitamin/mineral supplements, other dietary supplements, “nutraceuticals,” and hormones must be 
recorded in the subject’s source documentation (eg, clinical chart) and in the eCRF. This record 
should include the name of the drug, the dose, the route and date(s) of administration, and the 
indication for use. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 46 of 142 
7.8.1 
Permitted concomitant treatments (medications and therapies) 
No medication increases or additions are permitted for medications taken for PsA, apart from the 
protocol allowed background medications at a stable dose. However, a decrease in dose or 
dosing frequency of any agent is permitted for reasons of intolerance/AEs/side-effects at any 
time.  
Subjects are allowed to use acetaminophen/paracetamol and mild opioids as needed, except 
within 24 hours of study visit with disease activity assessment. 
Subjects who are already receiving an established antidepressant regimen should be on a stable 
dose of the antidepressant for 8 weeks prior to Baseline. 
Subjects are allowed to use any other medications, including biologics, after at least 28 days of 
last dose of the IMP. This is applicable for subjects who discontinue from IMP or the study 
early, including those permanently withdrawn from IMP, or subjects who have completed the 
study treatment without entering the extension study and are in the SFU Period. 
7.8.1.1 
Psoriasis treatments 
For treatment of PSO, subjects may continue to use topical moisturizers, emollients, salicylic 
acid preparations, bath oils, and oatmeal bath preparations for skin conditions during the study, 
as needed. Over-the-counter shampoos for the treatment of PSO of the scalp are also permitted. 
Additionally, mild topical steroids are permitted for use limited to the face, axillae, and/or 
genitalia, as needed. Subjects who use prohibited topical medications will be allowed to stay in 
the study but will counseled to not use them further. No other topical preparations are allowed in 
the 2 weeks prior to randomization or during the study unless medically required to treat an AE. 
See Table 7-2 for prohibited PSO medications. 
Use of psoralen and ultraviolet A light (PUVA/UVA) therapy for the treatment of PSO is not 
permitted for the duration of the study. 
7.8.2 
Prohibited concomitant treatments (medications and therapies) 
Prohibited and/or restricted medications are summarized in Table 7‒1 and Table 7-2. 
Table 7‒1: 
Prohibited or restricted medications and required wash-out periods 
Drug class 
Dose 
Exclusion/Washout 
Analgesics, including mild 
opioid analgesics, 
acetaminophen/paracetamol, etc 
Any dose  
Any ad hoc use in the 24 hours prior to any study 
visit.  
 
Stable doses of analgesics are permitted. 
NSAIDs/COX-2 inhibitors  
Any dose 
regimen 
Any change in dose/dose regimen in the 14 days 
prior to the Baseline Visit. For the duration of the 
study, a subject’s NSAIDs/COX-2 inhibitor dose 
must remain stable. 
Oral corticosteroids 
Any dose 
regimen 
Any change in dose/dose regimen in the 14 days 
prior to the Baseline Visit. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 47 of 142 
Table 7‒1: 
Prohibited or restricted medications and required wash-out periods 
Drug class 
Dose 
Exclusion/Washout 
Intramuscular/intravenous 
/intra-articular corticosteroids  
Any dose  
Use in the 28 days prior to the Baseline Visit and 
during the study. 
Intra-articular hyaluronic acid  
Any dose  
Use in the 6 months prior to the Baseline Visit. 
DMARDs: 
-azathioprine,  
-cyclosporine,  
-cyclophosphamide,  
-mycophenolic acid 
-mycophenolate mofetil 
-any other small molecule 
DMARDs (eg, tofacitinib) 
Any dose 
Use within 8 weeks prior to the Baseline Visit and 
during the study. 
-apremilast  
Any dose 
Use within 8 weeks prior to the Baseline Visit 
unless Inclusion Criterion #13 is met.  
-hydroxychloroquine  
Any dose 
Use within 8 weeks prior to the Baseline Visit 
unless Inclusion Criterion #13 is met.  
-sulfasalazine  
Any dose 
Use within 8 weeks prior to the Baseline Visit 
unless Inclusion Criterion #13 is met.  
-methotrexate  
Any dose 
regimen 
Initiation less than 12 weeks prior to the Baseline 
Visit unless Inclusion Criterion #11 is met.   
Administration of LEF and MTX together is not 
permitted at any time during the study. 
-leflunomide  
Any dose 
Use in the 6 months prior to the Baseline Visit, 
unless (1) a cholestyramine washout has been 
performed, in which case, use up to 28 days prior 
to the Baseline Visit is acceptable, or (2) Inclusion 
Criterion #12 is met. 
TNF inhibitor a 
 
-infliximab  
-adalimumab 
-etanercept  
-golimumab  
-certolizumab pegol  
Any dose 
For ADA, IFX, GOL, and CZP any use within the 
3 months prior to the Baseline Visit. 
 
For ETN, use within the 28 days prior to the 
Baseline Visit. 
 
This applies to biosimilar versions of any 
TNF inhibitor 
Any non-TNF biologic 
medications 
Any dose 
Any exposure history. 
ADA=adalimumab; COX-2=cyclooxygenase-2; CZP=certolizumab pegol; DMARD=disease-modifying 
antirheumatic drug; ETN=etanercept; GOL=golimumab; HCQ= hydroxychloroquine; IFX=infliximab; 
LEF=leflunomide; MTX=methotrexate; NSAID=nonsteroidal anti-inflammatory drug; SSZ=sulfasalazine; 
TNF=tumor necrosis factor 
a  Subjects must not have been exposed to more than 2 TNFα inhibitors prior to the Baseline Visit. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 48 of 142 
Table 7-2: 
Additional prohibited psoriasis treatments 
Drug class 
Dose 
Exclusion criteria 
Phototherapy 
Any dose 
Use within the 28 days prior to the Baseline Visit. 
Topical corticosteroids for 
dermatological use except as 
detailed in Section 7.8.1, 
vitamin D analogues, topical 
retinoids, keratolytics, coal tar, 
and fumaric acid esters 
Any dose 
Use within 14 days prior to the Baseline Visit. 
Systemic retinoids 
Any dose 
Use within 3 months prior to the Baseline Visit 
7.8.3 
Vaccines 
Administration of live (including attenuated) vaccines is not allowed during the conduct of the 
study and for 20 weeks after the final dose of the IMP (see Exclusion Criterion #9, Section 6.2). 
Administration of inactivated vaccines is allowed during the study at the discretion of the 
Investigator. 
Administration of inactivated vaccines is allowed during the study at the discretion of the 
Investigator. This includes administration of non-live coronavirus disease 2019 (COVID-19) 
vaccines authorized at the time of issuance of this protocol version (eg, messenger ribonucleic 
acid [mRNA], deoxyribonucleic acid [DNA] viral vector types of vaccines). Considering the 
known mechanism of action and results from a human vaccination response study, bimekizumab 
is not expected to affect the safety and/or efficacy of COVID-19 vaccines.  
7.9 
Blinding 
Due to differences in presentation between the bimekizumab and placebo treatments, special 
precautions will be taken to ensure study blinding and study sites will have blinded and 
unblinded personnel.  
7.9.1 
Procedures for maintaining and breaking the treatment blind 
7.9.1.1 
Maintenance of study treatment blind 
All subject treatment details will be allocated and maintained by the interactive voice or web 
response system (IXRS) system.  
7.9.1.2 
Breaking the treatment blind in an emergency situation 
The integrity of this clinical study must be maintained by observing the treatment blind. In the 
event of an emergency for which the appropriate treatment for a subject cannot be made without 
knowing the treatment assignment, it will be possible to determine to which treatment arm and 
dose the subject has been allocated by contacting the IXRS. All sites will be provided with 
details of how to contact the system for code breaking at the start of the study. The Medical 
Monitor or equivalent should be consulted prior to unblinding, whenever possible. 
The Clinical Project Manager (CPM) will be informed immediately via the IXRS when a code is 
broken but will remain blinded to specific treatment information. Any unblinding of the IMP 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 49 of 142 
performed by the Investigator must be recorded in the source documents and on the Study 
Termination eCRF page. 
7.10 
Randomization and numbering of subjects 
An IXRS will be used for assigning eligible subjects to a treatment regimen based on a 
predetermined production randomization and/or packaging schedule provided by UCB (or 
designee). The randomization schedule will be produced by the IXRS vendor. The IXRS will 
generate individual assignments for subject kits of IMP, as appropriate, according to the visit 
schedule. 
To enroll a subject, the Investigator or designee will contact the IXRS and provide brief details 
about the subject to be enrolled. Each subject will receive a 5-digit number assigned at Screening 
that serves as the subject identifier throughout the study. The subject number will be required in 
all communication between the Investigator or designee and the IXRS regarding a particular 
subject. Subject numbers and kit numbers will be tracked via the IXRS. 
Eligible subjects will be randomized to treatment groups at Baseline (Day 1). To randomize a 
subject, the Investigator or designee will contact the IXRS and provide brief details about the 
subject to be randomized. The IXRS will automatically inform the Investigator or designee of the 
subject’s randomization number. The IXRS will allocate kit numbers to the subject based on the 
subject number during the course of the study. The randomization number must be documented 
into the eCRF. 
8 
STUDY PROCEDURES BY VISIT  
The schedule of study assessments (Table 5-1) provides an overview of study assessments. A list 
of procedures to be completed at each visit is described below. Visit windows of ±3 days from 
the first dose at all visits through Week 16 are permissible. For the SFU Visit (20 weeks after the 
final dose), the visit should occur no more than 3 days prior to the scheduled visit date and 
within 7 days after the scheduled visit date (-3 days/+7 days). 
8.1 
Screening Period/Baseline  
8.1.1 
Screening 
The Screening Period will last for a minimum of 14 days and up to a maximum of 35 days. 
Prior to any study-specific activities, subjects will be asked to read, sign, and date an Informed 
Consent form that has been approved by the Sponsor and an IRB/IEC, and that complies with 
regulatory requirements. Subjects will be given adequate time to consider any information 
concerning the study given to them by the Investigator or designee. As part of the informed 
consent procedure, subjects will be given the opportunity to ask the Investigator any questions 
regarding potential risks and benefits of participation in the study. 
Where local regulations permit, subjects will also be given the option to participate in the 
genomics, genetics, and proteomics substudy. Subjects agreeing to participate in the substudy 
will be required to complete a separate Informed Consent form (ICF). The ICF must be signed 
prior to collecting any samples for the substudy. The substudy will only be conducted where 
ethically accepted and authorized by the regulatory agencies. Refusal to participate in the 
substudy will not affect a subject’s ability to participate in the main PA0011 study. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 50 of 142 
The following procedures or assessments will be performed at the Screening Visit: 
• Obtain written informed consent 
• Assessment of eligibility criteria 
• Collect demographic data 
• Collect PsA history 
• Collect significant past medical history and concomitant diseases 
• Record prior medications 
• Record concomitant medications 
• PHQ-9 
• eC-SSRS 
• Vital signs (pulse rate, BP, and temperature) 
• ECG by central reader 
• Collect samples for hematology, biochemistry and urinalysis 
• Collect samples for hs-CRP 
• Pregnancy testing (serum) 
• Urine drug screen 
• Collect samples for Hepatitis B and Hepatitis C testing  
• Collect samples for HIV testing 
• Collect samples for rheumatoid factor and anti-CCP antibodies 
• IGRA TB test 
• TB questionnaire 
• Physical examination 
• BSA affected by PSO 
• PASI 
• IGA 
• Perform TJC and SJC 
• Chest x-ray 
• X-ray of hands and feet 
• AEs 
• IXRS 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 51 of 142 
8.1.2 
Baseline (Day 1) 
• Assessment of eligibility criteria 
• Collect significant past medical history and concomitant diseases 
• Record concomitant medications 
• PHQ-9 
• eC-SSRS 
• Height 
• Weight  
• Vital signs (pulse rate, BP, and temperature) 
• Collect samples for hematology, biochemistry (including triglycerides, cholesterol, high 
density lipoprotein [HDL] cholesterol, and low density lipoprotein [LDL] cholesterol), and 
urinalysis 
• Collect samples for hs-CRP 
• Pregnancy testing (urine) 
• Collect sample for HLA-B27 
• Blood sample for bimekizumab plasma concentrations 
• Blood sample for anti-bimekizumab antibody detection 
• Serum and plasma blood samples for exploratory biomarkers (participating subjects only) 
• RNA blood samples for exploratory biomarkers (participating subjects only) 
• Blood samples for genetic/epigenetic analysis (participating subjects only) 
• TB questionnaire 
• Physical examination 
• BSA affected by PSO 
• PASI 
• IGA 
• Perform TJC and SJC 
• HAQ-DI 
• PtAAP 
• PhGA-PsA 
• PhGA-Arthritis 
• PGA-PsA 
• PGA-Arthritis  
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 52 of 142 
• mNAPSI 
• BASDAI 
• LEI 
• SPARCC 
• LDI 
• PsAQoL 
• PsAID-12 
• FACIT-Fatigue subscale 
• SF-36 
• EQ-5D-3L 
• WPAI-SHP 
• AEs 
• Randomization using IXRS 
• IMP administration (vital signs will be measured 30 minutes and 1 hour after dosing)  
8.2 
Double-Blind Treatment Period 
8.2.1 
Week 4 
• Record concomitant medications 
• PHQ-9 
• eC-SSRS 
• Vital signs (pulse rate, BP, and temperature) 
• Collect samples for hematology, biochemistry and urinalysis 
• Collect samples for hs-CRP 
• Pregnancy testing (urine) 
• Blood sample for bimekizumab plasma concentrations 
• Blood sample for anti-bimekizumab antibody detection 
• BSA affected by PSO 
• PASI 
• IGA 
• Perform TJC and SJC 
• HAQ-DI 
• PtAAP 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 53 of 142 
• PhGA-PsA 
• PhGA-Arthritis 
• PGA-PsA 
• PGA-Arthritis  
• BASDAI 
• mNAPSI 
• LEI 
• SPARCC 
• LDI 
• PsAQoL  
• PsAID-12 
• FACIT-Fatigue subscale 
• SF-36 
• EQ-5D-3L 
• AEs  
• IXRS 
• IMP administration  
8.2.2 
Week 8 
• Record concomitant medications 
• PHQ-9 
• eC-SSRS 
• Vital signs (pulse rate, BP, and temperature) 
• Collect samples for hematology, biochemistry and urinalysis 
• Collect samples for hs-CRP 
• Pregnancy testing (urine) 
• Blood sample for bimekizumab plasma concentrations 
• Blood sample for anti-bimekizumab antibody detection 
• BSA affected by PSO 
• PASI 
• IGA 
• Perform TJC and SJC 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 54 of 142 
• HAQ-DI 
• PtAAP 
• PhGA-PsA 
• PhGA-Arthritis 
• PGA-PsA 
• PGA-Arthritis  
• BASDAI 
• mNAPSI 
• LEI 
• SPARCC 
• LDI 
• AEs  
• IXRS 
• IMP administration  
8.2.3 
Week 12 
• Record concomitant medications 
• PHQ-9 
• eC-SSRS 
• Vital signs (pulse rate, BP, and temperature) 
• Collect samples for hematology, biochemistry and urinalysis 
• Collect samples for hs-CRP 
• Pregnancy testing (urine) 
• Blood sample for bimekizumab plasma concentrations 
• Blood sample for anti-bimekizumab antibody detection 
• IGRA TB test 
• TB questionnaire 
• BSA affected by PSO 
• PASI 
• IGA 
• Perform TJC and SJC 
• HAQ-DI 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 55 of 142 
• PtAAP 
• PhGA-PsA 
• PhGA-Arthritis 
• PGA-PsA 
• PGA-Arthritis  
• BASDAI 
• mNAPSI 
• LEI 
• SPARCC 
• LDI 
• PsAQoL 
• PsAID-12 
• FACIT-Fatigue subscale 
• SF-36 
• EQ-5D-3L 
• WPAI-SHP   
• AEs  
• IXRS 
• IMP administration  
8.2.4 
Week 16 
• Record concomitant medications 
• PHQ-9 
• eC-SSRS 
• Weight  
• Vital signs (pulse rate, BP, and temperature) 
• ECG by central reader 
• Collect samples for hematology, biochemistry (including triglycerides, cholesterol, 
HDL cholesterol, and LDL cholesterol), and urinalysis 
• Collect samples for hs-CRP 
• Blood sample for bimekizumab plasma concentrations 
• Blood sample for anti-bimekizumab antibody detection 
• Serum and plasma blood samples for exploratory biomarkers (participating subjects only) 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 56 of 142 
• RNA blood samples for exploratory biomarkers (participating subjects only) 
• Blood samples for genetic/epigenetic analysis (participating subjects only) 
• Pregnancy testing (urine) 
• TB questionnaire 
• Physical examination 
• BSA affected by PSO 
• PASI 
• IGA 
• Perform TJC and SJC 
• HAQ-DI 
• PtAAP 
• PhGA-PsA 
• PhGA-Arthritis 
• PGA-PsA 
• PGA-Arthritis  
• BASDAI 
• mNAPSI 
• LEI 
• SPARCC 
• LDI 
• PsAQoL 
• PsAID-12 
• FACIT-Fatigue subscale 
• SF-36 
• EQ-5D-3L 
• WPAI-SHP 
• AEs  
• IXRS 
At the completion of the Treatment Period, Investigators should discuss treatment options with 
the subject. All subjects who complete the study and do not enter the OLE study or who 
discontinue early, including those withdrawn from IMP, will have a SFU Visit 20 weeks after 
their final dose of IMP. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 57 of 142 
8.3 
Early Termination Visit 
Subjects withdrawing early from the study will undergo the following ET Visit assessments and 
will enter the SFU Period: 
• Record concomitant medications 
• PHQ-9 
• eC-SSRS 
• Weight 
• Vital signs (pulse rate, BP, and temperature) 
• ECG 
• Collect samples for hematology, biochemistry (including triglycerides, cholesterol, 
HDL cholesterol, and LDL cholesterol), and urinalysis 
• Collect samples for hs-CRP 
• Pregnancy testing (urine) 
• Blood sample for bimekizumab plasma concentrations 
• Blood sample for anti-bimekizumab antibody detection 
• TB questionnaire 
• Physical examination 
• BSA affected by PSO 
• PASI 
• IGA 
• Perform TJC and SJC 
• HAQ-DI 
• PtAAP 
• PhGA-PsA 
• PhGA-Arthritis 
• PGA-PsA 
• PGA-Arthritis  
• BASDAI 
• mNAPSI 
• LEI 
• SPARCC 
• LDI 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 58 of 142 
• PsAQoL 
• PsAID-12 
• FACIT-Fatigue subscale 
• SF-36 
• EQ-5D-3L 
• WPAI-SHP 
• AEs  
• IXRS 
8.4 
Safety Follow-Up Visit (20 weeks [-3 days/+7 days] after the final 
dose) 
All subjects who complete the study and do not enter the OLE study or who discontinue early, 
including those withdrawn from IMP, will have an SFU Visit 20 weeks after their final dose of 
IMP. 
• Record concomitant medications 
• PHQ-9 
• eC-SSRS 
• Weight 
• Vital signs (pulse rate, BP, and temperature) 
• ECG 
• Collect samples for hematology, biochemistry and urinalysis 
• Collect samples for hs-CRP 
• Pregnancy testing (urine) 
• Blood sample for bimekizumab plasma concentrations 
• Blood sample for anti-bimekizumab antibody detection 
• TB questionnaire 
• Physical examination 
• BSA affected by PSO 
• PASI 
• IGA 
• Perform TJC and SJC 
• HAQ-DI 
• PtAAP 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 59 of 142 
• PhGA-PsA 
• PhGA-Arthritis 
• PGA-PsA 
• PGA-Arthritis  
• BASDAI 
• LEI 
• SPARCC 
• LDI 
• PsAQoL 
• SF-36 
• AEs  
• IXRS 
8.5 
Unscheduled Visits 
At the Investigator’s discretion, an Unscheduled Visit may be completed at any time during the 
study but prior to the SFU Visit, if deemed necessary for the subject’s safety and well-being.  
If an Unscheduled Visit is conducted due to safety or efficacy reasons, an eC-SSRS assessment 
will be performed with the subject during the visit. If an Unscheduled Visit is conducted for 
reasons other than safety or efficacy concerns (eg, replacement of lost medication, repeated 
collection of a laboratory specimen due to collection or analysis issues), an eC-SSRS will not be 
required at these visits. 
At this visit, any of the following assessments may be performed, depending on the reason for 
the visit: 
• Record concomitant medication 
• eC-SSRS 
• Vital signs (pulse rate, BP, and temperature) 
• Physical examination 
• ECG  
• If indicated, obtain blood sample(s) for: 
− Standard safety laboratory tests (hematology/biochemistry/urinalysis) 
− Bimekizumab plasma concentrations and anti-bimekizumab antibody detection  
• An IGRA TB test 
• Obtain urine sample for urine pregnancy test 
• AEs 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 60 of 142 
9 
ASSESSMENT OF EFFICACY 
The ACR50 response at Week 16 is the primary efficacy variable. In addition, the ACR20 and 
ACR70 responses are secondary or other efficacy variables. Several assessments must be 
completed in order to determine the ACR response. These include the TJC and SJC based on 
68 and 66 joints, respectively, PGA-PsA, PhGA-PsA, PtAAP, HAQ-DI, and hs-CRP. The 
methods for the component measures will be described first, followed by ACR response and 
assessments used in secondary and other efficacy variables.  
The timing for all assessments is specified in the schedule of study assessments (Table 5-1).  
9.1 
Joint assessments 
9.1.1 
68/66 joint evaluation for ACR response and verification of Inclusion 
Criterion 5 
The TJC/SJC, as recommended by ACR in RA, is the 68/66 count and it has since also been used 
in PsA studies; therefore, it will be utilized in this study.  
All joint assessments will be performed by an experienced independent evaluator who has had 
documented training on how to perform these assessments correctly. Preferably, the same 
evaluator should perform these assessments at all visits, as indicated in Table 5-1. The 
independent evaluator will not be involved in any other assessments. The following joints will be 
assessed for tenderness:  
• Upper body (6) - bilateral temporomandibular, sternoclavicular, and acromioclavicular joints 
• Upper extremity (34) - bilateral shoulders, elbows, wrists (includes radiocarpal, and carpal 
and carpometacarpal bones considered as a single unit), metacarpophalangeal (I, II, III, IV, 
and V), thumb interphalangeals, proximal interphalangeal (II, III, IV, and V), and distal 
interphalangeals (II, III, IV, and V). 
• Lower extremity (28) - bilateral hips, knees, ankles, tarsi (includes subtalar, transverse tarsal, 
and tarsometatarsal considered as a single unit), metatarsophalangeals (I, II, III, IV, and V), 
great toe interphalangeals, and proximal interphalangeals (II, III, IV, and V). 
All of these except for the hips are assessed for swelling.  
Artificial and ankylosed joints, as well as missing joints (ie, amputated joints), are excluded from 
both tenderness and swelling assessments.  
One dactylitic digit is to be counted as 1 swollen joint (instead of counting as 3 in the finger or 
2 in the toe). 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 61 of 142 
Table 9-1 summarizes the swelling and tenderness grading criteria. 
Table 9-1: 
Swelling and tenderness grading 
Grade 
Tenderness response (68) 
Swelling response (66) 
0 
Not tender 
None 
1 
Tenderness present 
Detectable synovial thickening 
Data mapping from collected data to the grades listed in Table 9-1 will be described in the 
Statistical Analysis Plan (SAP). 
9.1.2 
28 joint evaluation for determination of DAS28(CRP) 
The following 28 joints will be used for calculation of the DAS28(CRP). 
• Upper extremity (26)-bilateral shoulders, elbows, wrists (includes radiocarpal, and carpal and 
carpometacarpal bones considered as a single unit), metacarpophalangeal joints I, II, III, IV, 
and V, thumb interphalangeals, proximal interphalangeal II, III, IV, and V 
• Lower extremity (2)-knees 
9.2 
ACR20, ACR50, and ACR70 response 
The ACR20, ACR50, and ACR70 response rates are based on a 20%, 50%, and 70% or greater 
improvement relative to Baseline in the following measures: 
• TJC based on 68 joints 
• SJC based on 66 joints 
• 3 of the 5 remaining core set measures: 
− PGA-PsA 
− PhGA-PsA 
− PtAAP 
− HAQ-DI 
− hs-CRP 
9.3 
Patient’s Global Assessments  
9.3.1 
Patient’s Global Assessment of Psoriatic Arthritis (PGA-PsA) 
The subject’s global assessment of PsA will be performed using a 100mm VAS scale where 0 is 
“very good, no symptoms” and 100 is “very poor, severe symptoms.” The subject will be asked 
the following question:  
“Considering all the ways your psoriatic arthritis affects you, please mark a vertical line on 
the scale below to show how well you are doing today.” 
The subject should be asked to consider all aspects of their disease (including joint and skin 
components) in their response to this question. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 62 of 142 
9.3.2 
Patient’s Global Assessment of Arthritis (PGA-arthritis) 
The subject’s global assessment of arthritis will be performed using a 100mm VAS scale where 
0 is “very good, no symptoms” and 100 is “very poor, severe symptoms.” The subject will be 
asked the following question: 
“Considering all the ways your arthritis affects you, please mark a vertical line on the scale 
below to show how you are feeling today.” 
The subject should be asked to consider their arthritis symptoms and functional capacity in their 
response to this question. 
9.4 
Physician’s Global Assessments 
These assessments will be performed by the Principal Investigator, another delegated physician, 
or an appropriately trained medical professional (based on local requirements) who has 
documented training on how to perform these assessments correctly. The assessments should be 
made blind to the PGA-PsA and PGA-arthritis assessments. 
9.4.1 
Physician’s Global Assessment of Psoriatic Arthritis (PhGA-PsA) 
The Investigator or delegate will assess the overall status of the subject with respect to their PsA, 
which may include any element of the disease and may include arthritis, PSO, enthesitis, 
dactylitis, or spondylitis. This will be assessed using a 100mm VAS scale where 0 is “very good, 
asymptomatic and no limitation of normal activities” and 100 is “very poor, very severe 
symptoms which are intolerable and inability to carry out all normal activities”. The Investigator 
or delegate will be asked the following question: 
“Considering all the ways the disease affects your patient, mark a vertical line on the scale 
for how well his or her condition is today.”  
9.4.2 
Physician’s Global Assessment of Arthritis (PhGA-Arthritis) 
The Physician or delegate will assess how the subject’s overall arthritis appears at the time of the 
visit. This is an evaluation based on the subject’s disease signs, functional capacity, and physical 
examination using a 100mm VAS scale where 0 is “very good” and 100 is “very poor”. The 
physician will be asked to mark the Patient’s arthritis:  
The Patient’s arthritis at this time is: 
“Please mark a vertical line on the scale below to assess the overall status of the subject's 
arthritis signs and symptoms and the functional capacity of the subject.” 
Very Good--------------------------------------------------------Very Poor 
9.5 
Patient’s Assessment of Arthritis Pain (PtAAP) 
The PtAAP VAS or ‘Pain VAS’ is part of the ACR core set of measures in arthritis 
(Felson et al, 1993). Subjects will assess their arthritis pain using a VAS where 0 is “no pain” 
and 100 is “most severe pain.”  
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 63 of 142 
9.6 
Health Assessment Questionnaire-Disability Index score 
(HAQ-DI) 
The HAQ-DI contains 20 items divided into 8 domains that measure: dressing and grooming, 
arising, eating, walking, hygiene, reach, grip, and common daily activities. Subjects are required 
to indicate the degree of difficulty they have experienced in each domain in the past week on a 
4-point scale that ranges from 0 (without difficulty) to 3 (unable to do). Any individual score of 
less than 2 is adjusted to 2 if the activity requires assistance from another individual or the use of 
an assistive device. The highest score in each category is then summed (0 to 24) and divided by 
the number of categories scored to give a score that ranges from 0 to 3.  
9.7 
High sensitivity C-reactive protein levels (hs-CRP) 
High sensitivity CRP levels will be analyzed by the central laboratory according to Table 5-1. 
After Screening, the hs-CRP data will not be sent to the Investigator in order to protect the 
blinded nature of the treatment assignments and response. 
9.8 
Evaluation of psoriasis 
9.8.1 
Body surface area psoriasis (BSA-PSO) 
In the BSA-PSO assessment, the subject’s hand (including the palm, fingers, and thumb) is used 
as the reference point for measuring how much of their skin is affected by PSO, representing 
roughly 1% of the body’s surface.  
The BSA palm method will be used for the evaluation of BSA affected by PSO as follows: 
• Head and neck=10% (10 palms) 
• Upper extremities=20% (20 palms) 
• Trunk=30% (30 palms) 
• Lower extremities=40% (40 palms)  
• Total BSA=100% 
9.8.2 
Psoriasis Area and Severity Index (PASI) 
The PASI will be assessed in all subjects with Baseline/Day 1 BSA affected by PSO ≥3% 
determined by the method described in Section 9.8.1 (ie, the BSA palm method).  
The PASI is the most commonly used and validated assessment for grading the severity of PSO 
in clinical studies (Feldman, 2005). The PASI quantifies the severity and extent of the disease 
and weighs these with the percentage of BSA involvement.  
The percent area of involvement (BSA%) is estimated across 4 body areas (head, upper limbs, 
trunk, and lower limbs) and then transferred into a grade (Table 9-2).  
The Investigator assesses the average redness, thickness, and scaliness of lesions in each body 
area (each on a 5-point scale); 0=none, 1=slight, 2=moderate, 3=marked, and 4=very marked.  
The PASI score ranges from 0 to 72 with a higher score indicating increased disease severity.  
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 64 of 142 
Table 9-2: 
Body areas for calculation of percent BSA for PASI 
Body area 
Details of area 
BSA 
Degree of involvement of 
body area a 
Head 
Face, back of head 
10%  
0 to 6 
Upper limbs 
Left, right, upper lower, flexor 
surface, extensor surface 
20%  
0 to 6 
Trunk 
Front, back, groin 
30%  
0 to 6 
Lower limbs  
Left, right, upper lower, flexor 
surface, extensor surface, including 
buttocks 
40%  
0 to 6 
Total 
 
100%  
 
BSA=body surface area; PASI=Psoriasis Area and Severity Index 
a Where 0=none; 1=1% to <10% affected, 2=10% to <30% affected, 3=30% to <50% affected, 4=50% to <70% 
affected, 5=70% to <90% affected, 6=90% to 100% affected 
The PASI75, PASI90, and PASI100 responses are based on at least 75%, 90%, and 100% 
improvement in the PASI score. The PASI will be assessed at Screening and at Baseline/Day 1. 
Thereafter, the PASI will be assessed for the purposes of determining response only in subjects 
with PSO involving at least 3% of BSA at Baseline/Day 1.  
9.8.3 
Investigator’s Global Assessment (IGA) 
A static IGA for PSO will be used to assess disease severity in all subjects during the study. The 
IGA will be completed at the visits specified in Table 5-1.  
The Investigator will assess the overall severity of PSO using the following 5-point scale 
presented in Table 9-3. 
Table 9-3: 
Five-point IGA 
Score 
Short Descriptor 
Detailed Descriptor 
0 
Clear 
No signs of PSO; post-inflammatory hyperpigmentation may 
be present  
1 
Almost Clear 
No thickening; normal to pink coloration; no to minimal focal 
scaling 
2 
Mild 
Just detectable to mild thickening; pink to light red coloration; 
predominantly fine scaling 
3 
Moderate 
Clearly distinguishable to moderate thickening; dull to bright 
red, moderate scaling  
4 
Severe 
Severe thickening with hard edges; bright to deep dark red 
coloration severe/coarse scaling covering almost all or all 
lesions 
IGA=Investigator's Global Assessment; PSO=psoriasis 
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 65 of 142 
The IGA responder is defined as a subject with a clear (0) or almost clear (1) assessment with at 
least a 2-category improvement from Baseline, meaning that this parameter will be evaluable 
only for subjects with psoriatic skin lesions (IGA score ≥2) at Baseline.    
In this study, only subjects with BSA ≥ 3% at Baseline will have IGA assessed at post-Baseline 
visits. 
9.8.4 
Modified Nail Psoriasis Severity Index (mNAPSI) 
Subjects with psoriatic nail disease will have a target nail selected at the Baseline Visit for 
evaluation using the mNAPSI. The nail selected should be the most affected nail observed at 
Baseline and should be the only one assessed throughout the study. The target nail will be scored 
(0 to 3) for onycholysis/oil drop dyschromia, nail plate crumbling, and pitting and will be scored 
(0 for “no” or 1 for “yes”) for leukonychia, nail bed hyperkeratosis, splinter hemorrhages, and 
red spots in the lunula.  
9.9 
Minimal Disease Activity (MDA) and Very Low Disease Activity 
(VLDA) 
Minimal Disease Activity and VLDA are states of disease activity deemed useful targets of 
treatment by both the subject and physician, given current treatment possibilities and limitations. 
Criteria covering all of the domains of the disease have been developed to determine whether or 
not a subject has reached MDA or VLDA based on key outcome measures in PsA (Mease, 2011; 
Coates et al, 2010).  
A subject is considered as having MDA if 5 or more of the following 7 criteria are fulfilled: 
• Tender joint count ≤1 
• Swollen joint count ≤1 
• PASI ≤1 or BSA ≤3 
• Patient pain VAS ≤15 
• PGA-PsA VAS ≤20 
• HAQ-DI ≤0.5 
• Tender enthesial points ≤1 
A subject is considered as having VLDA if all 7 of the above criteria are fulfilled. 
9.10 
Disease Activity Index for Psoriatic Arthritis (DAPSA) 
Disease Activity Index for Psoriatic Arthritis is a composite score of patient global and pain 
VAS, TJC/SJC, and hs-CRP that incorporates a pattern of peripheral arthritis that often is 
encountered in PsA, and is calculated as follows: 
 DAPSA=SJC (range 0 to 66) + TJC (range 0 to 68) + PGA-Arthritis (VAS range 0 to 10cm; 
0=best, 10=worst) + PtAAP (VAS range 0 to 10cm) + hs-CRP 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 66 of 142 
9.11 
Disease Activity Score-28 based on C-reactive protein 
(DAS28[CRP]) 
The components for DAS28(CRP) include the TJC and SJC based on 28 joints (Section 9.11), 
CRP (Section 9.7) and the PGA-arthritis (Section 9.3.2). The DAS28(CRP) is calculated as 
follows:  
𝐷𝐴𝑆28(𝐶𝑅𝑃) = 0.56  √𝑇𝐽𝐶+ 0.28  √𝑆𝐽𝐶+ 0.014   𝑃𝐺𝐴−𝐴𝑟𝑡ℎ𝑟𝑖𝑡𝑖𝑠+ 0.36   𝑙𝑛 (𝐶𝑅𝑃+ 1) + 0.96 
9.12 
Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) 
The BASDAI is the most common instrument used to measure the disease activity of AS from 
the subject’s perspective (Garrett et al, 1994) and is considered useful for evaluating axial 
involvement in subjects with PsA (Fernandez-Sueiro et al, 2009). The BASDAI is a validated 
self-reported instrument which consists of six 10-unit horizontal numeric rating scales to 
measure severity of fatigue, spinal and peripheral joint pain and swelling, enthesitis, and morning 
stiffness (both severity and duration, respectively) over the last week (van Tubergen et al, 2015). 
The final BASDAI score ranges from 0 to 10, with lower scores indicating lower disease 
activity.  
The BASDAI is calculated as follows:  
𝐵𝐴𝑆𝐷𝐴𝐼=
Q1 + Q2 + Q3 + Q4 + (𝑄5 + 𝑄6
2
)
5
 
 
9.13 
Leeds Enthesitis Index (LEI) 
Enthesitis, the inflammation at the bone insertion of tendon, ligament, or joint capsule, is 
common in PsA. The LEI is a new enthesitis index designed for use in PsA (Healy and Helliwell, 
2008) adopted for use in randomized controlled studies involving patients with PsA. Enthesitis 
will be assessed by palpation on the lateral epicondyles of the humerus (elbows), medial femoral 
epicondyles (knees), and Achilles tendons (heels) bilaterally and scored as 0=no pain and 
1=painful for each of the 6 sites, for a score range of 0 to 6. 
9.14 
Spondyloarthritis Research Consortium of Canada (SPARCC) 
The SPARCC is an index that measures the severity of enthesitis through the assessment of 
16 sites (the greater trochanter [right/left [R/L]), quadriceps tendon insertion into the patella 
(R/L), patellar ligament insertion into the patella and tibial tuberosity (R/L), Achilles tendon 
insertion (R/L), plantar fascia insertion (R/L), medial and lateral epicondyles (R/L), and the 
supraspinatus insertion [R/L]) (Maksymowych et al, 2009). Tenderness on examination is 
recorded as either present (1) or absent (0) for each of the 16 sites, for an overall score range of 
0 to 16. 
9.15 
Leeds Dactylitis Index (LDI) 
Dactylitis, the swelling of an entire digit related to articular and periarticular inflammation is a 
characteristic of inflammatory spondyloarthropathies, including PsA. Presence of dactylitis will 
be assessed using the LDI basic. It measures the ratio of the circumference of the affected digit to 
the circumference of the digit on the contralateral hand or foot (millimeters): a minimum 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 67 of 142 
difference of 10% is used to define a dactylitic digit (Healy and Helliwell, 2007; 
Helliwell et al, 2005). If the contralateral digit is also dactylitic, a table of normative values 
based on population averages is used to provide the comparison. The ratio is then multiplied by 
the tenderness score, using a simple grading system (0=absent, 1=present). The results from each 
digit with dactylitis are then summed to produce a final score. The digits involved and the 
matching contralateral digit will also be recorded at the same visits. 
9.16 
Psoriatic Arthritis Quality of Life (PsAQoL) 
The use of the PsAQoL is recommended by the health regulatory authorities as 1 of the 
disease-specific HRQoL measures in PsA (CHMP/EWP/438/04). The PsAQoL comprises 
20 items so that the score ranges from 0 to 20 with higher scores indicating worse HRQoL. 
9.17 
Psoriatic Arthritis Impact of Disease-12 (PsAID-12) 
The PsAID-12 is a patient-reported outcome measure for assessing the impact of PsA in 
12 physical and psychological domains, including pain, fatigue, skin problems, work and/or 
leisure activities, functional capacity, discomfort, sleep disturbance, coping, 
anxiety/fear/uncertainty, embarrassment and/or shame, social participation, and depression. Each 
domain is assessed with a single question using a 0 to 10 numerical rating scale. Each domain 
score is multiplied by a weighting factor and the results are then summed to provide the total 
score. The total score ranges from 0 to 10, with higher scores indicating a worse status. The 
PsAID-12 demonstrated satisfactory psychometric properties in an international validation study; 
however, further validation is needed (Gossec et al, 2014). A score below 4 out of 10 is 
considered a patient-acceptable status. A change of 3 or more points is considered relevant 
absolute change.  
9.18 
Functional Assessment of Chronic Illness Therapy (FACIT)-
Fatigue subscale 
The FACIT-Fatigue is a 40-item measure that assesses self-reported fatigue and its impact upon 
daily activities and function over the past 7 days (FACIT.org). The scale consists of 5 subscales 
(physical well-being, social/family well-being, emotional well-being, functional well-being, and 
fatigue). The fatigue subscale is the only one used in this study . It is composed of 13 items, all 
scored from 0 (Not at all) to 4 (Very much). The FACIT-Fatigue subscale score ranges from 0 to 
52 with 0 being the worst possible score and 52 being the best possible score. To obtain a score 
from 0 to 52, all negatively worded questions have to be recoded, so that responses range from 
worst (0) to the best (4) outcome. 
The FACIT–Fatigue subscale has been validated in patients with PsA. The minimum 
clinically-important difference for FACIT-Fatigue subscale in patients with PsA was determined 
to be a 4-point change (Cella et al, 2019). 
9.19 
Short-Form 36-item Health Survey (SF-36) 
The SF-36 (version 2, standard recall) is a 36-item generic HRQoL instrument that uses a recall 
period of 4 weeks. Items are grouped into 8 domains as follows: Physical Functioning (10 items), 
Role Physical (4 items), Bodily Pain (2 items), General Health (5 items), Vitality (4 items), 
Social Functioning (2 items), Role Emotional (3 items), Mental Health (5 items), and 1 item for 
perceived stability or change in health (Health Transition) during the last year. The concepts 
represented by these domains contribute to physical, mental, and social aspects of HRQoL. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 68 of 142 
In addition to domain scores, the PCS and MCS scores are calculated from the 8 domains 
(excluding the Health Transition item). Component scores reflect the impact of each domain on 
physical and mental health status. The norm-based T-scores for the 2 SF-36 component summary 
(PCS and MCS) and the 8 domains are standardized with a mean of 50 and a standard deviation 
(SD) of 10 in the general US population (Maruish, 2011). An individual respondent’s score that 
falls outside the T-score range of 45 to 55 should be considered outside the average range for the 
US general population. When considering group-level data, a score below 47 should be 
considered indicative of impaired functioning within that health domain or dimension. Similar to 
individual respondent data, group mean scores of 47 or greater should be considered average or 
above average as compared to the general US population. Higher scores indicate a better health 
status. 
9.20 
Euro Quality of life 5-Dimensions-3 Level (EQ-5D-3L) 
The EQ-5D-3L is comprised of a 5-item health status dimension and a VAS. The response to 
each of the 5 health status dimensions is divided into 3 levels (no problem, some or moderate 
problems, or extreme problems) and is scored as 1, 2, and 3, respectively. The EQ-5D-3L VAS 
records the respondent’s self-rated health status on a vertical 20cm scale, 0 to 100 graduated 
(0=worst imaginable health status, 100=best imaginable health status). 
9.21 
Work Productivity and Activity Impairment Questionnaire – 
Specific Health Problem (WPAI-SHP) 
The WPAI-SHP V2.0 is a patient-reported questionnaire that assesses subject’s employment 
status, work absenteeism, work impairment while working (presenteeism), overall work, and 
daily activity impairment attributable to a specific health problem (Reilly et al, 1993).  
Five out of 6 items of the WPAI-SHP are regrouped into the 4 dimensions, with scores expressed 
as percentage, where higher numbers indicate greater impairment and less productivity (ie, worse 
outcomes) as described in the WPAI-SHP scoring rules. 
9.22 
Psoriatic Arthritis Response Criteria (PsARC) 
The PsARC is based on the TJC (68 joints) and SJC (66 joints), the PGA-PsA and PhGA-PsA 
VAS.  
The PsARC response is defined as improvement from Baseline in at least 2 of the 4 measures 
(TJC, SJC, PGA-PsA, PhGA-PsA) 1 of which must be TJC or SJC and no worsening from 
Baseline in any of the 4 measures. Improvement for TJC and SJC is defined as a reduction of 
≥30% and worsening is defined as an increase of ≥30%. Improvement of PGA-PsA and 
PhGA-PsA is defined as a reduction of the 100-point VAS of ≥20 points and worsening is 
defined as an increase of the 100-point VAS of ≥20. 
9.23 
Psoriatic Arthritis Disease Activity Score (PASDAS) 
The PASDAS (Coates et al, 2014) is a composite score that includes patient and physician global 
scores of skin and joint disease, SJC, TJC, LEI, tender dactylitis count, the physical component 
of the SF-36 Health Survey, and level of CRP. It was developed by the Group for Research and 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 69 of 142 
Assessment of Psoriasis and Psoriatic Arthritis and the European League Against Rheumatism. 
PASDAS is calculated using the following equation: 
PASDAS = (((0.18 × √Physician global VAS) + (0.159 × √Patient global VAS) − 
(0.253 × √SF36 − PCS) + (0.101 × LN (SJC + 1)) + (0.048 × LN (TJC + 1)) + (0.23 × 
LN (LEI + 1)) + (0.377 LN (tender Dactylitis count + 1)) + (0.102 × LN (CRPmg/dL 
+ 1)) +2)*1.5. 
Note: LN=natural logarithm 
The following categories are used to define the level of disease activity (Coates et al, 2018): 
• Remission: PASDAS ≤1.9 
• Low disease activity: PASDAS 1.9 to <3.2 
• Moderate disease activity: PASDAS 3.2 to <5.4 
• High disease activity: PASDAS ≥5.4 
10 
ASSESSMENT OF PHARMACOKINETIC AND 
PHARMACOGENOMIC VARIABLES 
10.1 
Pharmacokinetic variable 
The PK variable is the plasma concentrations of bimekizumab.   
The Investigator or designee will obtain blood samples for these measurements at the time points 
specified in Table 5-1. When these samples are required at a visit during which the subject is 
dosed with IMP, the blood samples will be drawn prior to dosing. Samples should be drawn at 
the same time of the sampling for clinical laboratory tests. The time and date of collection will be 
recorded in the eCRF. Instructions pertaining to sample collection, processing, storage, labeling, 
and shipping are provided in the laboratory manual for this study. Detailed information on 
sample analysis will be provided in a bioanalytical report. 
10.2 Pharmacogenomic variables 
A separate ICF will be required for those subjects who agree to participate in the genomics, 
genetics, and proteomics substudy, and must be signed prior to collection of any samples for the 
substudy. The substudy will only be conducted where ethically accepted and authorized by the 
regulatory agencies. Refusal to participate in the substudy will not affect a subject’s ability to 
participate in the main study. 
These analyses will enable evaluation of biomarkers relative to disease biology and progression, 
drug treatment and inflammatory and immune response processes. The nature and format of 
these tentative analyses will be determined at a later date. 
For individuals consenting to the genomics, genetics, and proteomics substudy, blood samples 
will be drawn for exploratory genetic/epigenetic, genomic, proteomic, and metabolomics 
analysis and for candidate exploratory biomarker analyses. Candidate exploratory biomarker 
evaluations may include, but are not limited to, IL 17A/IL-17F pathway signaling and PsA 
biology (eg, IL-17A, IL-17F, IL-23, IL-6, tumor necrosis factor, dendritic cell-specific 
transmembrane protein, and circulating osteoclast precursors). 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 70 of 142 
Collection of these samples will occur at the time points specified in the schedule of study 
assessments (Table 5-1). At dosing visits, blood samples will be drawn prior to dosing, and will 
be drawn at the same time of the sampling for clinical laboratory tests. The time and date of 
collection will be recorded in the eCRF. The samples will be stored at -80°C at the central 
biorepository for up to 20 years. 
Detailed information on the collection, storage, preparation, and shipping of samples for 
potential RNA, proteins, lipids, and metabolites analysis will be presented in the Laboratory 
Manual. 
The nature and format of these tentative analyses will be determined at a later date. Results for 
the exploratory parameters obtained from potential RNA, lipids, proteins and metabolites 
analysis will be described in a separate report. 
11 
ASSESSMENT OF IMMUNOLOGICAL VARIABLES 
Immunological variables are the anti-bimekizumab antibody status, and the treatment-emergent 
antibody positivity derived from anti-drug antibody assays.  
The Investigator or designee will obtain blood samples for these measurements at the time points 
specified in Table 5-1. When these samples are required at a visit during which the subject is 
dosed with IMP, the blood samples will be drawn prior to dosing. Samples should be drawn at 
the same time of the sampling for clinical laboratory tests. The time and date of collection will be 
recorded in the eCRF. Instructions pertaining to sample collection, processing, storage, labeling, 
and shipping are provided in the laboratory manual for this study. The presence of antibodies to 
bimekizumab will be determined using a validated bioanalytical method. Detailed information on 
sample analysis will be provided in a bioanalytical report.  
The presence of anti-bimekizumab antibodies will be determined using a tiered approach of 
screening, confirmatory, and titer assays. Where applicable, a neutralizing-antibody assay will be 
performed. 
12 
ASSESSMENT OF SAFETY 
12.1 
Adverse events 
12.1.1 
Definitions 
12.1.1.1 
Adverse event 
An AE is any untoward medical occurrence in a patient or clinical investigation subject 
administered a pharmaceutical product that does not necessarily have a causal relationship with 
this treatment. An AE can therefore be any unfavorable and unintended sign (including an 
abnormal laboratory finding), symptom, or disease temporally associated with the use of a 
medicinal (investigational) product, whether or not related to the medicinal (investigational) 
product. 
In order to ensure complete safety data collection, all AEs occurring during the study (ie, after 
the signing of the Informed Consent form), including any pretreatment and post-treatment 
periods required by the protocol, must be reported in the eCRF even if no IMP was taken but 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 71 of 142 
specific study procedures were conducted. This includes all AEs not present prior to the initial 
visit and all AEs that recurred or worsened after the initial visit. 
Signs or symptoms of the condition/disease for which the IMP is being studied should be 
recorded as AEs only if their nature changes considerably or their frequency or intensity 
increases in a clinically significant manner as compared to the clinical profile known to the 
Investigator from the subject’s history or the Baseline Period. 
12.1.1.2 
Serious adverse event 
Once it is determined that a subject experienced an AE, the seriousness of the AE must be 
determined. An SAE must meet 1 or more of the following criteria: 
• Death 
• Life-threatening 
(Life-threatening does not include a reaction that might have caused death had it occurred in 
a more severe form.) 
• Significant or persistent disability/incapacity 
• Congenital anomaly/birth defect (including that occurring in a fetus) 
• Important medical event that, based upon appropriate medical judgment, may jeopardize the 
patient or subject and may require medical or surgical intervention to prevent 1 of the other 
outcomes listed in the definition of serious 
(Important medical events may include, but are not limited to, potential Hy’s Law [see 
Section 12.1.1.3], allergic bronchospasm requiring intensive treatment in an emergency room 
or at home, blood dyscrasias that do not result in inpatient hospitalization, or the 
development of drug dependency or drug abuse.) 
• Initial inpatient hospitalization or prolongation of hospitalization 
(A patient admitted to a hospital, even if he/she is released on the same day, meets the 
criteria for the initial inpatient hospitalization. An emergency room visit that results in 
admission to the hospital would also qualify for the initial inpatient hospitalization criteria. 
However, emergency room visits that do not result in admission to the hospital would not 
qualify for this criteria and, instead, should be evaluated for 1 of the other criteria in the 
definition of serious [eg, life-threatening adverse experience, important medical event]. 
Hospitalizations for reasons not associated with the occurrence of an AE [eg, preplanned 
surgery or elective surgery for a pre-existing condition that has not worsened or manifested 
in an unusual or uncharacteristic manner] do not qualify for reporting. For example, if a 
subject has a condition recorded on his/her medical history and later has a preplanned surgery 
for this condition, it is not appropriate to record the surgery or hospitalization as an SAE, 
since there is no AE upon which to assess the serious criteria. Please note that, if the 
pre-existing condition has worsened or manifested in an unusual or uncharacteristic manner, 
this would then qualify as an AE and, if necessary, the seriousness of the event would need to 
be determined.) 
Note: Confirmed active TB is an SAE and must be captured on an SAE Report Form and 
provided to the Sponsor in accordance with SAE reporting requirements. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 72 of 142 
12.1.1.2.1 
Anticipated serious adverse events 
The following anticipated SAEs are anticipated to occur in the population studied in this protocol 
at some frequency that is independent of drug exposure. Note that listed events will not be 
regarded as anticipated SAEs if they are life threatening or if they result in the death of the study 
subject. 
This list does not change the Investigator’s obligation to report all SAEs (including anticipated 
SAEs) as detailed in Section 12.1.2.3. 
Table 12-1: Anticipated SAEs for the population of subjects with PsA 
MedDRA system organ class 
MedDRA preferred terms 
Eye disorders 
Uveitis 
Cardiac disorders 
Myocardial infarction 
Atrial fibrillation 
Gastrointestinal disorders 
Crohn's disease 
Hepatobiliary disorders 
Non-alcoholic steatohepatitis 
Metabolism and Nutrition disorders 
Metabolic syndrome 
Diabetes mellitus 
Musculoskeletal and connective tissue disorders 
Psoriatic arthropathy 
Neoplasms benign, malignant and unspecified 
(including cysts and polyps) 
Basal cell carcinoma 
Squamous cell carcinoma 
Nervous system disorders 
Embolic Stroke 
Ischaemic Stroke 
Psychiatric disorders 
Anxiety 
Depression 
Skin and subcutaneous tissue disorders 
Psoriasis 
MedDRA=Medical Dictionary for Regulatory Activities; PsA=psoriatic arthritis; SAE=serious adverse event 
Note: Exception: Listed events will not be regarded as anticipated SAEs if they are life threatening or if they 
result in the death of the study subject. 
12.1.1.3 
Adverse events of special interest 
An AE of special interest is any AE that a regulatory authority has mandated be reported on an 
expedited basis, regardless of the seriousness, expectedness, or relatedness of the AE to the 
administration of a UCB product/compound. 
Potential Hy’s Law, defined as ≥3xULN ALT or AST with coexisting ≥2xULN total bilirubin in 
the absence of ≥2xULN ALP, with no alternative explanation for the biochemical abnormality, 
must ALWAYS be reported to UCB as an AE of special interest (ie, without waiting for any 
additional etiologic investigations to have been concluded). Follow-up information should then 
be reported if an alternative etiology is identified during investigation and monitoring of the 
subject. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 73 of 142 
12.1.1.4 
Other safety topics of interest 
Prespecified safety topics of interest for the study are: infections (serious, opportunistic, fungal, 
and TB), neutropenia, hypersensitivity, suicidal ideation, and behavior, major cardiovascular 
events, liver function test changes/enzyme elevations, malignancies, and inflammatory bowel 
diseases (with gastroenterology referral, as appropriate).  
This is based on findings from the IMP clinical program to date, potential risks generally 
associated with biologic immunomodulators, or findings from other medicines with a related 
mechanism of action. There are no specific AE reporting requirements for these topics; however, 
special monitoring, additional data collection activities, and/or enhanced signal detection 
activities (within UCB) are in place. 
12.1.2 
Procedures for reporting and recording adverse events 
The subject will be given the opportunity to report AEs spontaneously. A general prompt will 
also be given at each study visit to detect AEs. For example: 
“Did you notice anything unusual about your health (since your last visit)?” 
In addition, the Investigator should review any self-assessment procedures employed in the 
study. 
12.1.2.1 
Description of adverse events 
When recording an AE, the Investigator should use the overall diagnosis or syndrome using 
standard medical terminology, rather than recording individual symptoms or signs. The eCRF 
and source documents should be consistent. Any discrepancies between the subject’s own words 
on his/her own records and the corresponding medical terminology should be clarified in the 
source documentation. 
When recording the intensity of an AE in the CRF (ie, mild, moderate, or severe), the 
Investigator should use the following criteria: 
• Mild: the subject is aware of the sign or symptom (syndrome), but it does not interfere with 
his/her usual activities and/or is of no clinical consequence 
• Moderate: the AE interferes with the usual activities of the subject or it is of some clinical 
consequence 
• Severe: the subject is unable to work normally or to carry out his/her usual activities, or the 
AE is of definite clinical consequence 
Details for completion of the AE eCRF (including judgment of relationship to IMP) are 
described in the eCRF Completion Guidelines. 
12.1.2.2 
Rule for repetition of an adverse event 
An increase in the intensity of an AE should lead to the repetition of the AE being reported with: 
• The outcome date of the first AE that is not related to the natural course of the disease being 
the same as the start date of the repeated AE, and the outcome of “worsening” 
• The AE verbatim term being the same for the first and repeated AE, so that the repeated AE 
can be easily identified as the worsening of the first one 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 74 of 142 
12.1.2.3 
Additional procedures for reporting serious adverse events 
If an SAE is reported, UCB must be informed within 24 hours of receipt of this information by 
the site. The Investigator must enter the information regarding the SAE into the appropriate 
eCRFs and transmit to UCB via the clinical database, even if the data are incomplete, or if it is 
obvious that more data will be needed in order to draw any conclusions. This information will be 
received by UCB and entered into the global safety database. Any ancillary documentation (eg, 
autopsy or other documentation) that is valid for the SAE can be sent to UCB using the contact 
information (fax/email) for SAE reporting listed in the Serious Adverse Event Reporting section 
at the front of the protocol. 
It is important for the Investigator, when entering the SAE data into the eCRF, to include the 
assessment as to a causal relationship between the SAE and the IMP administration. This insight 
from the Investigator is very important for UCB to consider in assessing the safety of the IMP 
and in determining whether the SAE requires reporting to the regulatory authorities in an 
expedited manner. 
Additional information received by the Investigator must be provided within 24 hours. All 
documents in the local language must be accompanied by a translation in English or the relevant 
information included in the same document must be summarized in the eCRF and transmitted to 
UCB via the clinical database. 
The Investigator is specifically requested to collect and report to UCB (or its representative) any 
SAEs (even if the Investigator is certain that they are in no way associated with the IMP), up to 
30 days from the end of the study for each subject, and to also inform participating subjects of 
the need to inform the Investigator of any SAE within this period. Serious AEs that the 
Investigator thinks may be associated with the IMP must be reported to UCB regardless of the 
time between the event and the end of the study. 
Upon receipt of the electronic transmission of the SAE, UCB will perform as assessment of 
expectedness of the reported SAE. The assessment of expectedness of the SAE is based on the 
IB. 
12.1.3 
Follow up of adverse events 
An AE should be followed until it has resolved, has stable sequelae, the Investigator determines 
that it is no longer clinically significant, or the subject is lost to follow up. This follow-up 
requirement applies to AEs, SAEs, and AEs of special interest; AEs of special monitoring, 
further details regarding follow up of PDILI events is provided in Section 12.2.1.4.  
If an AE is ongoing at the end of the study for a subject, follow up should be provided until 
resolution/stable level of sequelae is achieved, or until the Investigator no longer deems that it is 
clinically significant, or until the subject is lost to follow up. If no follow up is provided, the 
Investigator must provide a justification. The follow up will usually be continued for 20 weeks 
after the subject has discontinued his/her IMP. 
Information on SAEs obtained after clinical database lock will be captured through the Patient 
Safety (PS) database without limitation of time. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 75 of 142 
12.1.4 
Pregnancy 
If the Investigator is notified that a subject has become pregnant after the first intake of any IMP, 
the Investigator must immediately (within 24 hours) notify UCB’s PS department by entering all 
pregnancy information into the eCRF. An automatic notification will be sent to UCB PS. The 
subject should be permanently withdrawn from IMP as soon as pregnancy is known (by positive 
pregnancy test), and the following should be completed: 
• The subject should immediately stop the intake of the IMP. 
• The subject should return for an early ad-hoc study visit. 
• A Safety Follow-Up Visit should be scheduled 20 weeks after the final dose of IMP. 
The Investigator should discuss with the subject the possibility to continue the study by attending 
the scheduled visits for assessments without IMP administration. The tests or assessments, which 
are considered contraindicated during the pregnancy should not be performed. The early ad-hoc 
study visit will be considered as the ET visit if the subject does not wish to pursue the study 
investigations. 
The Investigator must inform the subject of information currently known about potential risks 
and about available treatment alternatives. 
The pregnancy will be documented in the eCRF provided to the Investigator. The progression of 
the pregnancy and the eventual birth (if applicable) must be followed up using the eCRF in 
which the Investigator has to report on the health of the mother and of the child. Every 
reasonable attempt should be made to follow the health of the child for 30 days after birth for any 
significant medical issues. In certain circumstances, UCB may request that follow up is 
continued for a period longer than 30 days. If the subject is lost to follow up and/or refuses to 
give information, written documentation of attempts to contact the subject needs to be provided 
by the Investigator and filed at the site. UCB’s PS department is the primary contact for any 
questions related to the data collection for the pregnancy, eventual birth, and follow up. 
In cases where the partner of a male subject enrolled in a clinical study becomes pregnant, the 
Investigator or designee is asked to contact the subject to request consent of the partner via the 
Partner Pregnancy Consent form that has been approved by the responsible IRB/IEC and should 
be available in the Investigator site file. In case of questions about the consent process, the 
Investigator may contact the UCB/contract research organization (CRO) contract monitor for the 
study. The Investigator will complete the information in the eCRF only after the partner has 
agreed that additional information can be captured and has provided the signed Partner 
Pregnancy Consent form. UCB’s PS department is also the primary contact for any questions 
related to the data collection for partner pregnancy, eventual birth, and follow-up. 
A pregnancy becomes an SAE in the following circumstances: miscarriage, elective abortion, 
medically indicated abortion (eg, when the pregnancy is endangering life or health of woman or 
when fetus will be born with severe abnormalities), unintended pregnancy after hormonal 
contraceptive failure (if the hormonal contraceptive was correctly used), ectopic pregnancy, fetal 
demise, or any congenital anomaly/birth defect of the baby. Those SAEs must be additionally 
reported using the eCRF. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 76 of 142 
12.1.5 
Suspected transmission of an infectious agent via a medicinal 
product 
For the purposes of reporting, any suspected transmission of an infectious agent via a medicinal 
product should be considered as an SAE; such cases must be reported immediately, recorded in 
the AE module of the eCRF, and followed as any other SAE. Any organism, virus, or infectious 
particle (eg, prion protein transmitting transmissible spongiform encephalopathy), pathogenic or 
nonpathogenic, is considered an infectious agent. 
12.1.6 
Overdose of investigational medicinal product 
Excessive dosing (beyond that prescribed in the protocol and including overdose) should be 
recorded in the eCRF. Any SAE or nonserious AE associated with excessive dosing must be 
followed as any other SAE or nonserious AE. These events are only considered AEs or SAEs if 
there are associated clinical signs and symptoms or if the act of taking the excess medicine itself 
is an AE or SAE (eg, suicide attempt). 
12.1.7 
Safety signal detection 
Selected data from this study will be reviewed periodically to detect as early as possible any 
safety concern(s) related to the IMP so that Investigators, clinical study subjects, regulatory 
authorities, and IRBs/IECs will be informed appropriately and as early as possible. 
The Study Physician or medically qualified designee/equivalent will conduct an ongoing review 
of SAEs and perform ongoing SAE reconciliations in collaboration with the PS representative. 
As appropriate for the stage of development and accumulated experience with the IMP, 
medically qualified personnel at UCB may identify additional safety measures (eg, AEs, vital 
signs, laboratory or ECG results) for which data will be periodically reviewed during the course 
of the study. 
In addition, an independent Data Monitoring Committee (DMC) will periodically review and 
monitor the safety data from this study and advise UCB. The DMC membership includes 
clinicians knowledgeable about the disease or the treatment. All members have experience and 
expertise in clinical studies. Board members may not participate in the study as principal or 
co-Investigators, or as study subject care physicians. The duration of membership for the DMC 
will be inclusive of planned analyses for PA0011. The DMC may also be asked to provide a 
review of final study results, as deemed appropriate. The DMC procedures will ensure that data 
remain blind to the study team and Investigators at all times throughout the conduct of the study. 
The detailed role, scope, responsibilities, and complete procedures, as well as the identity of the 
DMC members, will be described in a separate charter document. A Cardiovascular Adjudication 
Committee and a Neuropsychiatric Adjudication Committee will be in place for this study. 
Specific procedures will be outlined in the charters, which will be developed by the committee 
members. 
12.2 
Laboratory measurements 
Clinical laboratory assessments consist of serum biochemistry, hematology, urinalysis and 
pregnancy tests (serum or urine) (Table 5-1). A centralized laboratory will be used to supply all 
laboratory test supplies and analyze all blood and urine samples for hematology and 
biochemistry. Any unscheduled laboratory testing should also be collected using the central 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 77 of 142 
laboratory (with the exception of urgent safety laboratory measurements which should be 
performed locally and centrally simultaneously). Testing to rule out hepatitis B, hepatitis C, and 
HIV will be performed at Screening. Rheumatoid factor and anti-CCP testing will also be 
performed at Screening. Testing of HLA-B27 will be performed at Baseline. 
Specific details regarding the handling and processing of serum biochemistry and hematology, 
are provided in the study laboratory manuals. 
Laboratory parameters to be measured are presented in Table 12-2. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 78 of 142 
Table 12-2: Laboratory measurements 
Hematology 
Biochemistry 
Urinalysis  
Basophils 
Calcium 
pH 
Eosinophils 
Chloride 
Albumin (protein) 
Lymphocytes 
Magnesium 
Glucose 
 Monocytes 
Potassium 
Blood 
 Neutrophils 
Sodium 
Leukocyte esterase 
 Hematocrit 
Glucose 
Nitrite 
 Hemoglobin 
BUN 
Urine dipstick for pregnancy testing b 
 MCH 
Creatinine 
Urine drug screen c 
 MCHC 
hs-CRP 
 
 MCV 
AST 
 
 Platelet count 
ALT 
 
 RBC count 
GGT 
 
 WBC count 
ALP 
 
 
Total bilirubin 
 
 
Triglyceridesa 
 
 
Cholesterola 
 
 
HDL cholesterola 
 
 
LDL cholesterola 
 
 
LDH 
 
 
Serum pregnancy testing b 
 
ALP=alkaline phosphatase; ALT=alanine aminotransferase; AST=aspartate aminotransferase; BUN=blood urea 
nitrogen; ET=early termination; GGT=gamma-glutamyltransferase; HDL=high density lipoprotein; hs-
CRP=high sensitivity C-reactive protein; IMP=investigational medicinal product; LDH=lactate dehydrogenase; 
LDL=low density lipoprotein; MCH=mean corpuscular hemoglobin; MCHC=mean corpuscular hemoglobin 
concentration; MCV=mean corpuscular volume; RBC=red blood cell; SFU=Safety Follow-Up; WBC=white 
blood cell 
a Biochemistry will include triglycerides, cholesterol, HDL cholesterol, and LDL cholesterol at Baseline, Week 
16, and at the ET Visit. 
b Pregnancy testing will consist of serum testing at the Screening Visit for all women of childbearing potential. 
The pregnancy test will be urine at all other visits. 
c Urine drug screen will be performed at the Screening Visit. 
12.2.1 
Evaluation of potential drug-induced liver injury 
The PDILI IMP discontinuation criteria for this study are provided in Section 6.3.1, with the 
accompanying required follow-up investigation and monitoring detailed below. All PDILI events 
must be reported as AEs and PDILI events meeting SAE criteria should be reported to the study 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 79 of 142 
site and Sponsor within 24 hours of learning of their occurrence. Any PDILI event that meets the 
criterion for potential Hy’s Law must be reported within 24 hours of learning of their occurrence 
as an AE of special interest (see Section 12.1.1.3), and, if applicable, also reported as an SAE 
(see Section 12.1.1.2).  
Evaluation of PDILI consists of the diagnostic testing and continued monitoring included in 
Table 12‒3 (specific tests dependent on laboratory results and corresponding symptoms) and 
consultation with a local hepatologist (if applicable; discussed in Section 12.2.1.1). The local 
hepatologist is the expert usually consulted by the treating physician for assessment and 
management of potential hepatic disease. This would usually be a hepatologist but may be a 
gastroenterologist. Additional investigation and monitoring may be required and adapted based 
on the diagnosis after the cause of the liver injury/abnormality is confirmed (details in 
Section 12.2.1.4).  
The results of all monitoring, including laboratory testing and other testing, should be made 
available to the study site and Sponsor. 
All initial tests resulting in abnormal hepatic laboratory values need to be repeated, but 
appropriate medical action must not be delayed waiting for the repeat result. 
If tests are done locally for more rapid results, a concurrent sample should also be sent to the 
central laboratory whenever possible. Medical care decisions are to be made initially using the 
most rapidly available results and a conservative approach must be taken if the results from the 
2 laboratory tests are significantly different. Data from the local and central laboratory are to be 
recorded on the applicable eCRF pages. 
When IMP is discontinued, all concomitant medications and herbal supplements that are not 
medically necessary should also be discontinued. In these cases, the Investigator should also 
consider dose reduction for medically necessary concomitant medication and consider changing 
any medically required concomitant medication known to be hepatotoxic to a suitable 
alternative. 
When IMP is stopped due to PDILI (as described in Section 6.3.1), IMP must be permanently 
discontinued unless a subsequent alternative diagnosis fully explains the hepatic findings. If a 
subsequent alternative diagnosis fully explains the hepatic findings, and the requirements 
provided in Section 12.2.1.2.1 are met, rechallenge with IMP may be appropriate. 
The approach to investigate PDILI is summarized in Table 12‒3. 
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 80 of 142 
Table 12‒3: Required investigations and follow-up for PDILI 
Laboratory value 
 
Immediate 
Follow up 
ALT or 
AST 
Total 
bilirubin 
Symptomsa of 
hepatitis of 
hypersensitivity 
Consultation 
requirements 
Actions 
Testing 
Evaluation 
≥3xULN 
≥2xULNb NA 
Hepatology consultc 
Medical Monitor must 
be notified within 
24 hours (eg, by 
laboratory alert) and 
subject discussed with 
Medical Monitor 
ASAP. 
 
Immediate IMP 
discontinuation.d 
 
 
 
Essential: Must have 
repeat liver 
chemistry values 
and additional 
testing completed 
ASAP (see 
Section 12.2.1.3); 
recommended to 
occur at the site with 
HCP. 
Monitoring of liver 
chemistry values at least 
twice per week until 
values normalize, 
stabilize, or return to 
within baseline values.e 
≥3xULN 
NA 
Yes 
≥8xULN 
NA 
NA 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 81 of 142 
Table 12‒3: Required investigations and follow-up for PDILI 
Laboratory value 
 
Immediate 
Follow up 
ALT or 
AST 
Total 
bilirubin 
Symptomsa of 
hepatitis of 
hypersensitivity 
Consultation 
requirements 
Actions 
Testing 
Evaluation 
≥5xULN 
(and ≥2x 
baseline) 
and 
<8xULN  
<2xULN 
No 
Discussion with 
Medical Monitor 
required. 
Consider need for 
hepatology consult if 
there is no evidence of 
resolution (see Follow 
up requirements).c 
Further investigation 
– immediate IMP 
discontinuation not 
required (see 
Section 12.2.1.2). 
 
IMP discontinuation 
required if any of the 
following occur: 
• 
Subject cannot 
comply with 
monitoring 
schedule. 
• 
Liver chemistry 
values continue 
to increase. 
• 
Liver chemistry 
values remain 
≥5xULN (and 
≥2x baseline) 
after 4 weeks of 
monitoring 
without evidence 
of resolution. 
Essential: Every 
attempt must be 
made to have repeat 
liver chemistry 
values and 
additional testing 
completed within 
48 hours at the site 
with HCP (see 
Section 12.2.1.3). 
Monitoring of liver 
chemistry values at least 
twice per week for 
2 weeks.e 
• 
Immediate IMP 
discontinuation 
required if liver 
chemistry values 
continue to increase. 
After 2 weeks of 
monitoring liver 
chemistry values: 
• 
ALT or AST remains 
≥5xULN <8xULN, 
IMP should be 
temporarily withheld 
and subject should 
undergo repeat test in 
2 weeks. 
• 
Continue IMP if ALT 
or AST values 
<5xULN; continue to 
monitor at least twice 
per week until values 
normalize, stabilize, 
or return to within 
baseline values. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 82 of 142 
Table 12‒3: Required investigations and follow-up for PDILI 
Laboratory value 
 
Immediate 
Follow up 
ALT or 
AST 
Total 
bilirubin 
Symptomsa of 
hepatitis of 
hypersensitivity 
Consultation 
requirements 
Actions 
Testing 
Evaluation 
• 
If ALT or AST 
remains ≥5xULN 
after second re-test, 
immediate IMP 
discontinuation 
required. 
Continue to monitor until 
values normalize, 
stabilize, or return to 
within baseline values.e 
ALP=alkaline phosphatase; ALT=alanine aminotransferase; ASAP=as soon as possible; AST=aspartate aminotransferase; HCP=healthcare practitioner; 
IMP=investigational medicinal product; NA=not applicable; PDILI=potential drug-induced liver injury; ULN=upper limit of normal 
a Hepatitis symptoms include fatigue, nausea, vomiting, and right upper quadrant pain or tenderness; hypersensitivity symptoms include eosinophilia (>5%), 
rash, and fever (without clear alternative cause). 
b If the subject also has ≥2xULN ALP, the possibility of an indication of biliary obstruction should be discussed with the Medical Monitor. 
c Details provided in Section 12.2.1.1. The local hepatologist is the expert usually consulted by the treating physician for assessment and management of 
potential hepatic disease. This would usually be a hepatologist but may be a gastroenterologist. 
d Details are provided in Section 12.2.1.2.  
e Unless an alternative monitoring schedule is agreed by the Investigator and UCB responsible physician. Determination of stabilization is at the discretion of the 
Investigator in consultation with the hepatologist (as applicable) and UCB responsible physician, as needed. 
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 83 of 142 
12.2.1.1 
Consultation with Medical Monitor and local hepatologist  
Potential drug-induced liver injury events require notification of the Medical Monitor within 
24 hours (eg, by laboratory alert), and the subject must be discussed with the Medical Monitor as 
soon as possible. If required, the subject must also be discussed with the local hepatologist. The 
local hepatologist is the expert usually consulted by the treating physician for assessment and 
management of potential hepatic disease. This would usually be a hepatologist but may be a 
gastroenterologist. If determined necessary, this discussion should be followed by a full 
hepatology assessment (see Section 12.2.1.3) and SAE report (if applicable). 
12.2.1.2 
Immediate action: determination of IMP discontinuation 
All PDILI events require immediate action, testing, and monitoring.  
The immediate action is dependent on the laboratory values and symptoms of hepatitis or 
hypersensitivity and ranges from continuation of IMP (followed by immediate investigation) to 
immediate and permanent discontinuation (see Section 6.3.1 and Table 12‒3 for details). 
When IMP is discontinued, all concomitant medications and herbal supplements that are not 
medically necessary should also be discontinued. The Investigator should also consider dose 
reduction for medically necessary concomitant medication and consider changing any medically 
required concomitant medication known to be hepatotoxic to a suitable alternative. 
12.2.1.2.1 
IMP restart/rechallenge  
Subjects who are immediately discontinued from IMP due to having met certain criteria for 
PDILI (as described in Section 6.3.1 and Table 12‒3), but for whom an alternative diagnosis is 
confirmed, ie, drug-induced liver injury is excluded, can rarely restart IMP. Rechallenge with 
IMP can occur only if ALL of the following requirements are met at the time of the rechallenge: 
• The results of additional testing and monitoring described in Section 12.2.1.3 and 
Section 12.2.1.4 confirm a nondrug-related cause for the abnormal hepatic laboratory 
parameters and any associated symptoms (ie, a subsequent alternative diagnosis fully 
explains the hepatic findings).  
• No alternative treatment options are available to the subject. 
• The subject has shown clear therapeutic benefit from the IMP. 
• Subject’s ALT or AST elevations do not exceed ≥3xULN. 
• Subject’s total bilirubin is <1.5xULN. 
• Subject has no signs or symptoms of hypersensitivity.  
• The rechallenge is approved by the UCB responsible physician and a hepatologist. The 
hepatologist must be external to UCB. It is recommended that the hepatologist be a local 
hepatology expert or the hepatologist treating the subject. 
• Subject agrees to the investigator-recommended monitoring plan and understands their 
individual benefit/risk for restarting IMP and this is adequately documented.  
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 84 of 142 
12.2.1.3 
Testing: identification/exclusion of alternative etiology 
The measurements and additional information required for the assessment of PDILI events when 
there is a reasonable possibility that they may have been caused by the IMP are detailed in 
Table 12-4 (laboratory measurements) and Table 12-5 (additional information). Results of the 
laboratory measurements and information collected are to be submitted to the Sponsor on the 
corresponding eCRF. If the medical history of the subject indicates a requirement for other 
assessments not included below, these additional assessments should be completed and 
submitted, as applicable. 
All blood samples should be stored, if possible. If tests are done locally for more rapid results, a 
concurrent sample must also be sent to the central laboratory. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 85 of 142 
The following measurements are to be assessed: 
Table 12-4: PDILI laboratory measurements 
Virology-
related 
Hepatitis A IgM antibody 
HBsAg 
Hepatitis E IgM antibody 
HBcAb-IgM 
Hepatitis C RNA 
Cytomegalovirus IgM antibody 
Epstein-Barr viral capsid antigen IgM antibody (if unavailable, obtain heterophile 
antibody or monospot testing) 
Immunology 
Anti-nuclear antibody (qualitative and quantitative) 
Anti-smooth muscle antibody (qualitative and quantitative) 
Type 1 anti-liver kidney microsomal antibodies (qualitative and quantitative) 
Hematology 
Eosinophil count 
Urinalysis 
Toxicology screena 
Chemistry 
Amylase 
Sodium, potassium, chloride, glucose, BUN, creatinine 
Total bilirubin, ALP, AST, ALT, GGT, total cholesterol, albumin 
If total bilirubin ≥1.5xULN, obtain fractionated bilirubin to obtain % direct bilirubin 
Serum CPK and LDH to evaluate possible muscle injury causing transaminase 
elevation 
Additional 
Prothrombin time/INRb 
Serum pregnancy test 
PK sample 
ALT=alanine aminotransferase; CPK=creatine phosphokinase; HBcAb-IgM=hepatitis B core antibody-IgM; 
HBsAg=hepatitis B surface antigen; IgM=immunoglobulin M; INR=international normalized ratio; 
LDH=lactate dehydrogenase; PDILI=potential drug-induced liver injury; PK=pharmacokinetic; 
RNA=ribonucleic acid; ULN=upper limit of normal 
a For detecting substances (ie, amphetamines, benzodiazepines, opioids, marijuana, cocaine, phencyclidine, and 
tricyclic antidepressants), additional tests may be performed based on the Investigator’s medical judgment and 
subject’s history. 
b Measured only for subjects with ALT >8xULN, elevations in total bilirubin, and symptoms of hepatitis or 
hypersensitivity. Hepatitis symptoms include fatigue, nausea, vomiting, and right upper quadrant pain or 
tenderness; hypersensitivity symptoms include eosinophilia (>5%), rash, and fever (without clear alternative 
cause). 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 86 of 142 
Additional information to be collected is presented in Table 12-5.  
Table 12-5: PDILI information to be collected 
New or updated information 
Concomitant prescription and over-the-counter medications (eg, acetaminophen, herbal remedies, 
vitamins); dosages and dates should be included. 
Pertinent medical history, including the following: 
• 
History of liver disease (eg, autoimmune hepatitis, nonalcoholic steatohepatitis or other “fatty 
liver disease”) 
• 
Adverse reactions to drugs 
• 
Allergies 
• 
Relevant family history or inheritable disorders (eg, Gilbert’s syndrome, alpha-1 antitrypsin 
deficiency) 
• 
Recent travel  
• 
Progression of malignancy involving the liver (Note: Metastatic disease to the liver, by itself, 
should not be used as an explanation for significant AST and/or ALT elevations.) 
The appearance or worsening of clinical symptoms of hepatitis or hypersensitivity (eg, fatigue, nausea, 
vomiting, right upper quadrant pain or tenderness, decreased appetite, abdominal pain, jaundice, fever, 
or rash) 
Recent clinically significant hypotension or hypoxemia with compromised cardiopulmonary function 
Alcohol and illicit drug use 
Results of liver imaging or liver biopsy, if done 
Results of any specialist or hepatology consult, if done 
Any postmortem/pathology reports 
ALT=alanine aminotransferase; AST=aspartate aminotransferase; PDILI=potential drug-induced liver injury 
12.2.1.4 
Follow-up evaluation 
Potential drug-induced liver injury events require follow-up monitoring as described in 
Table 12‒3. Monitoring should continue until liver chemistry values normalize, stabilize, or 
return to baseline. Determination of stabilization is at the discretion of the Investigator in 
consultation with the hepatologist (as applicable) and UCB responsible physician, as needed. 
12.3 
Other safety measurements 
12.3.1 
Vital signs 
The Investigator or designee should measure all vital signs (BP, temperature [oral, axillary, or 
otic], and pulse rate) after the subject has been sitting for at least 5 minutes, and the subject 
should remain seated during the measurements. At Baseline, vital signs will be measured prior to 
IMP administration and then at approximately 30 minutes and 1 hour after dosing. At all other 
administrations of IMP, vital signs will be measured only once prior to dosing. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 87 of 142 
12.3.2 
Body weight and height 
The Investigator or designee will measure the height of the subject with shoes removed in meters 
and the weight of the subject in kilograms. The same scale should be utilized throughout the 
study where possible. 
12.3.3 
Physical examination 
The physical examination should be conducted by the Investigator or designee at the time points 
listed in Table 5-1 and will include general appearance; ear, nose, and throat; eyes, hair, and 
skin; respiratory; cardiovascular; gastrointestinal; musculoskeletal; hepatic; neurological 
(including limb reflexes); and mental status. Findings considered clinically significant changes 
since the physical examination at the Screening Visit will be recorded as AEs. 
12.3.4 
12-lead electrocardiogram 
The Investigator or designee will perform the ECGs which will be read centrally. Full details of 
ECG recording will be provided in the ECG Manual. 
12.3.5 
Patient Health Questionnaire-9 (PHQ-9)  
The PHQ-9 is a multipurpose instrument for screening, diagnosing, monitoring, and measuring 
the severity of depression. The PHQ-9 scores for depression range from 0 to 27 with higher 
scores indicating worse state. A score of 5 to 9 is considered to be minimal symptoms of 
depression. A score of 10 to 14 is considered minor depression, dysthymia, or mild major 
depression. A score of 15 to 19 is considered to indicate moderately severe major depression, 
and a score >20 is considered to be severe major depression.  
The PHQ-9 will be assessed at the visits specified in Table 5-1.  
Refer to Section 6.3 for PHQ-9-related withdrawal criteria. 
12.3.6 
Assessment and management of TB and TB risk factors 
All subjects will be assessed for TB at Screening and at the time points specified in the schedule 
of study assessments (Table 5-1) through physical examination for signs and symptoms of TB, 
chest x-ray (Section 12.3.6.2), laboratory testing (Section 12.3.6.1), and subject questionnaire 
(Section 12.3.6.3).  
At Screening, all subjects will have an IGRA test (QuantiFERON TB Test is recommended), a 
chest x-ray (unless already performed within 3 months of Screening) and examination for signs 
and symptoms of TB. In addition, each subject will complete a TB questionnaire directed at 
potential exposure to TB and symptoms of TB.  
For the purposes of this study, TB definitions are as follows: 
a. Known TB infection: 
− Active TB infection or clinical signs and symptoms suspicious for TB (pulmonary or 
extra-pulmonary). 
− History of active TB infection involving any organ system or findings in other organ 
systems consistent with TB infection, unless adequately treated and proven to be fully 
recovered upon consult with a TB specialist. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 88 of 142 
− Any evidence by radiography or other imaging modalities consistent with previously 
active TB infection that is not reported in the subject’s medical history. 
b. High risk of acquiring TB infection: 
− Known close exposure to another person with active TB infection within the 3 months 
prior to Screening. 
− Time spent in a healthcare delivery setting or institution where individuals infected with 
TB are housed and where the risk of transmission of infection is high. 
c. Latent TB infection (unless appropriate prophylaxis is initiated at least 4 weeks prior to IMP 
dosing and continued to completion of prophylaxis): 
− The absence of signs, symptoms, or physical findings suggestive of TB infection with a 
positive IGRA test (or 2 indeterminate IGRA test results) and a chest x-ray (or other 
imaging) without evidence of TB infection. If the result of the IGRA test is 
indeterminate, the particular IGRA test previously performed may be repeated once; if 
positive or indeterminate on retest, the subject may not be randomized to IMP without 
further evaluation by a TB specialist and discussion with the Study Physician, if LTB 
infection is identified. The retest must be done during the protocol-defined Screening 
window. 
− Note: If available, respiratory or other specimens must also be smear and culture negative 
for TB (Center for Disease Control diagnosis of LTBI; http://www.cdc.gov/TB/topic 
/testing/default.htm). 
d. NTMB infection is defined as a clinical infection caused by mycobacterial species other than 
those belonging to the Mycobacterium tuberculosis complex. 
e. Tuberculosis test conversion: 
− A positive IGRA result for the current test when previous IGRA test results were 
negative. All subjects with TB test conversion must immediately stop IMP administration 
and be referred to a TB specialist for further evaluation. Confirmed TB test conversions 
should be classified as due to LTBI, active TB infection, or NTMB, and reported to the 
UCB PS function. 
Subject eligibility, retesting requirements, and treatment requirements are presented in 
Figure 12-1. A schematic diagram of TB test results during the study is presented in Figure 12‒2. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 89 of 142 
Figure 12-1: Schematic diagram of TB test results and study eligibility 
 
CDC=Center for Disease Control; IGRA-interferon-gamma release assay; LTBI= latent tuberculosis infection; 
TB=tuberculosis; WHO=World Health Organization 
a IGRA retest must be done during the protocol-defined Screening window. 
b Subject has a past history of active TB involving any organ system unless adequately treated according to 
WHO/CDC therapeutic guidance and proven to be fully recovered upon consult with a TB specialist. Subjects who 
have recently (no more than 12 months prior to Screening) completed full treatment course of prophylaxis for 
LTBI are allowed. Prophylaxis should be in accordance with WHO/CDC guidelines and TB specialist judgment 
based on the origin of infection.  
c Subjects with LTBI may enter the study only after they have completed at least 4 weeks of appropriate 
prophylactic therapy and thereafter, will continue and complete the entire regimen. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 90 of 142 
Figure 12‒2: Schematic diagram of TB test results during the study 
 
ASAP=as soon as possible; IGRA-interferon-gamma release assay; LTBI=latent tuberculosis infection; 
TB=tuberculosis;  
a IGRA retest must be done ASAP and prior to the next dose. 
b Subjects with LTBI may continue the study only after they have completed at least 4 weeks of appropriate 
prophylactic therapy and thereafter, will continue and complete the entire regimen.  
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 91 of 142 
12.3.6.1 
Tuberculosis assessment by IGRA 
During conduct of the study, the TB assessment by IGRA (QuantiFERON-TB Test is 
recommended) will be performed as described in Table 5-1 for all subjects. The test results will 
be reported as positive, negative, or indeterminate. Positive and indeterminate TB test results that 
occur during the course of the study must be reported as an AE and appropriately updated once 
the final diagnosis is known (eg, active TB, latent TB, or false positive TB test). UCB also 
recommends that a TB specialist be consulted where TB (latent or active) is suspected or if there 
are doubts regarding test results. If latent or active TB is identified, subjects must undergo 
appropriate study-specified withdrawal procedures. The retest during Screening must be done 
during the protocol-defined Screening window. 
12.3.6.2 
Chest x-ray for tuberculosis 
A plain posteroanterior chest x-ray must be performed in the Screening Period unless one has 
been performed within 3 months prior to the Screening Visit. The chest x-ray (or, if done, 
Computed Axial Tomography of the chest) must be clear of signs of TB infection (previous or 
current) before first IMP administration. All chest imaging (particularly x-rays) should be 
available for review by the Investigator before randomization of the subject. The chest x-ray 
reading should be repeated if the TB test was confirmed positive. If the second read of the 
pretreatment chest x-ray is confirmed to be clear, the subject may be included in the study 
4 weeks after the start of the TB prophylactic treatment. If the pretreatment chest x-ray is not 
available for a re-read, it should be repeated after notification to the radiologist that this subject 
is IGRA positive and confirmed to be clear for signs of TB. 
The chest imaging must be negative for any old or recent TB infection as determined by a 
qualified radiologist and/or pulmonary physician. Any new clinically significant findings post 
Baseline on chest x-ray must be documented in the source documents and the eCRF as an AE. 
12.3.6.3 
Tuberculosis questionnaire 
The questionnaire “Evaluation of signs and symptoms of tuberculosis” should be used as a 
source document. The questionnaire will be completed as described in Table 5-1. The 
questionnaire will assist with the identification of subjects who may require therapy for TB. A 
subject who answers “Yes” to the question 
 
 at Screening 
is excluded. A “Yes” response to any of the other questions within the questionnaire at Screening 
should trigger further careful assessment to determine if subject has LTB or active TB (see 
Exclusion Criterion #11 in Section 6.2). A “Yes” response to any of the questions during the 
study should trigger further assessments to determine if the subject has either LTB or active TB 
infection.   
12.3.6.4 
Tuberculosis management 
LTB infection and active TB identified during study 
During the study, subjects who develop evidence of LTB infection or active TB must 
immediately stop further administration of IMP and will be referred to an appropriate TB 
specialist (pulmonologist or infectious disease specialist) for further evaluation. Evidence of 
LTB infection is defined as subject’s IGRA test converts to positive or indeterminate (and 
confirmed indeterminate on repeat), or the subject’s questionnaire or history and physical 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 92 of 142 
indicates that TB infection or exposure may have occurred. Evidence of active TB includes, in 
addition to the aforementioned tests, signs and symptoms of organ involvement. In either 
situation, the subject should be carefully assessed by a TB specialist for active TB. Subjects 
diagnosed with active TB should be withdrawn from the study and receive appropriate TB or 
prophylaxis therapy.  
If a TB specialist excludes an active TB infection, the subject can proceed with the IMP no 
earlier than 4 weeks after the start of an appropriate prophylactic therapy. 
Any presumptive diagnosis or diagnosis of a TB infection is a reportable event. Confirmed active 
TB must be reported as an SAE. The Investigator is to complete and submit the TB follow-up 
form provided. 
The subject should be transferred to the care of his/her physician and managed according to the 
best available standard of care. Subjects identified as having converted to active TB during the 
study must be withdrawn and scheduled to return for the ET Visit as soon as possible but no later 
than the next scheduled study visit and complete all ET Visit assessments.  
The subject should be encouraged to complete a SFU Visit (20 weeks after the final dose of 
IMP). 
If infection with NTMB is identified during the study, the same procedure as for active TB 
acquired during the study must be followed. 
12.3.7 
Pregnancy testing 
Pregnancy testing will consist of serum testing at Screening for all women of childbearing 
potential. The pregnancy test will be urine at all other visits. 
The Screening Visit serum pregnancy testing results must be negative and received and reviewed 
prior to randomization. A negative urine pregnancy test result should be obtained immediately 
prior to each administration of IMP at the visits specified in Table 5-1. Pregnancy tests should be 
administered to all female subjects of childbearing potential, regardless of their use of birth 
control.  
12.3.8 
Assessment of suicidal ideation and behavior 
Suicidal ideation and behavior will be assessed by trained study personnel using the eC-SSRS. 
This scale will be used to assess suicidal ideation and behavior that may occur during the study. 
The visits at which the eC-SSRS assessments will be performed are specified in the schedule of 
study assessments (Table 5-1). 
The eC-SSRS is a standardized and validated instrument developed for the assessment of the 
severity and frequency of suicidal ideation and behavior (Posner et al, 2011; Mundt et al, 2010). 
Subjects respond to standardized clinical questions that are presented in a uniform fashion. The 
eC-SSRS defines 5 subtypes of suicidal ideation and behavior in addition to self-injurious 
behavior with no suicidal intent. The eC-SSRS takes approximately 3 to 10 minutes to complete. 
Refer to Section 6.3 for eC-SSRS-related withdrawal criteria.  
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 93 of 142 
13 
STUDY MANAGEMENT AND ADMINISTRATION  
13.1 
Adherence to protocol 
The Investigator should not deviate from the protocol. However, the Investigator should take any 
measure necessary in deviation from or not defined by the protocol in order to protect clinical 
study subjects from any immediate hazard to their health and safety. In this case, this action 
should be taken immediately, without prior notification of the regulatory authority, IRB/IEC, or 
Sponsor. 
After implementation of such measure, the Investigator must notify the CPM of the Sponsor 
within 24 hours and follow any local regulatory requirements. 
13.2 
Monitoring 
UCB (or designee) will monitor the study to meet the Sponsor’s monitoring SOPs, ICH-GCP 
guideline, and applicable regulatory requirements, and to ensure that study initiation, conduct, 
and closure are adequate. Monitoring of the study may be delegated by UCB to a CRO or a 
contract monitor. 
The Investigator and his/her staff are expected to cooperate with UCB (or designee) and to be 
available during the monitoring visits to answer questions sufficiently and to provide any 
missing information. The Investigator(s)/institution(s) will permit direct access to source 
data/documents for study-related monitoring, audits, IRB/IEC review, and regulatory 
inspection(s). 
The Investigator will allow UCB (or designee) to periodically review all eCRFs and 
corresponding source documents (eg, hospital and laboratory records for each study participant). 
Monitoring visits will provide UCB (or designee) with the opportunity to evaluate the progress 
of the study, verify the accuracy and completeness of eCRFs, ensure that all protocol 
requirements, applicable authorities’ regulations, and Investigator’s obligations are being 
fulfilled, and resolve any inconsistencies in the study records. 
13.2.1 
Definition of source data 
All source documents must be accurate, clear, unambiguous, permanent, and capable of being 
audited. They should be made using some permanent form of recording (ink, typing, printing, 
optical disc). They should not be obscured by correction fluid or have temporary attachments 
(such as removable self-stick notes). Photocopies and/or printouts of eCRFs are not considered 
acceptable source documents. 
Source documents are original records in which raw data are first recorded. These may include 
hospital/clinic/general practitioner records, charts, diaries, x-rays, laboratory results, printouts, 
pharmacy records, care records, ECG or other printouts, completed scales, or QoL 
questionnaires, for example. Source documents should be kept in a secure, limited access area. 
Source documents that are computer generated and stored electronically must be printed for 
review by the monitor (eg, ECG reports). Once printed, these copies should be signed and dated 
by the Investigator and become a permanent part of the subject’s source documents. The 
Investigator will facilitate the process for enabling the monitor to compare the content of the 
printout and the data stored in the computer to ensure all data are consistent. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 94 of 142 
Electronic data records, such as Holter monitor records or electroencephalogram records, must 
be saved and stored as instructed by UCB (or designee). 
Electronic Patient-Reported Outcome (ePRO) measures (eg, PtAAP, EQ-5D-3L, SF-36, 
PGA-PsA, and PGA-arthritis) will be completed by each subject and will be collected 
electronically. 
The data collection and database management system will be supplied by a vendor and will be 
compliant with the relevant regulations. The data collected on the ePROs will be uploaded to a 
central server database and will be sent electronically to UCB (or a designated CRO). 
13.2.2 
Source data verification 
Source data verification ensures accuracy and credibility of the data obtained. During monitoring 
visits, reported data are reviewed with regard to being accurate, complete, and verifiable from 
source documents (eg, subject files, recordings from automated instruments, tracings [ECG], 
x-ray films, laboratory notes). All data reported on the eCRF should be supported by source 
documents, unless otherwise specified in Section 13.2.1. 
13.3 
Data handling 
13.3.1 
Case Report form completion 
This study will use electronic data capture (EDC); the Investigator is responsible for prompt 
reporting of accurate, complete, and legible data in the eCRFs and in all required reports. 
Any change or correction to the eCRF should be dated, initialed, and explained (if necessary) 
and should not obscure the original entry.  
Corrections made after the Investigator’s review and signature of the completed eCRF will be 
resigned and dated by the Investigator. 
The Investigator should maintain a list of personnel authorized to enter data into the eCRF. The 
Investigator is responsible for prompt reporting of accurate, complete, and legible data in the 
electronic eCRFs and in all required reports.  
Detailed instructions on the use of the EDC will be provided in the eCRF Completion 
Guidelines. 
Any change or correction to the eCRF after saving must be accompanied by a reason for the 
change. Corrections made after the Investigator’s review and approval (by means of a 
password/electronic signature) will be reapproved by the Investigator. 
13.3.2 
Database entry and reconciliation 
Case Report forms/external electronic data will be entered/loaded into a validated electronic 
database using a clinical data management system (CDMS). Computerized data cleaning checks 
will be used in addition to manual review to check for discrepancies and to ensure consistency of 
the data. Case Report form data are entered into the clinical database using independent, 
double-data entry, with the exception of comment fields, which are verified by a second person. 
The data are entered into the eCRFs once and are subsequently verified if the study is performed 
using electronic data capture. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 95 of 142 
An electronic audit trail system will be maintained within the CDMS to track all data changes in 
the database once the data have been saved initially into the system or electronically loaded. 
Regular backups of the electronic data will be performed. 
13.3.3 
Subject Screening and Enrollment log/Subject Identification Code list 
The subject’s screening and enrollment will be recorded in the Subject Screening and Enrollment 
Log. 
The Investigator will keep a Subject Identification Code list. This list remains with the 
Investigator and is used for unambiguous identification of each subject. 
The subject’s consent and enrollment in the study must be recorded in the subject’s medical 
record. These data should identify the study and document the dates of the subject’s 
participation. 
13.4 
Termination of the study 
UCB reserves the right to temporarily suspend or prematurely discontinue this study either at a 
single site, multiple sites, or at all sites at any time for reasons including, but not limited to, 
safety or ethical issues, inaccurate or incomplete data recording, noncompliance, or 
unsatisfactory enrollment with respect to quality or quantity. 
If the study is prematurely terminated or suspended, UCB (or its representative) will inform the 
Investigators/institutions and the regulatory authority(ies) of the termination or suspension and 
the reason(s) for the termination or suspension, in accordance with applicable regulatory 
requirement(s). The IRB/IEC should also be informed and provided with reason(s) for the 
termination or suspension by the Sponsor or by the Investigator/institution, as specified by the 
applicable regulatory requirement(s). In addition, arrangements will be made for the return of all 
unused IMP and other material in accordance with UCB procedures for the study. 
13.5 
Archiving and data retention 
The Investigator will maintain adequate records for the study, including eCRFs, medical records, 
laboratory results, Informed Consent documents, drug dispensing and disposition records, safety 
reports, information regarding participants who discontinued, and other pertinent data. 
All essential documents are to be retained by the Investigator until at least 2 years after the last 
approval of a marketing application in an ICH region and until there are no pending or 
contemplated marketing applications in an ICH region, or at least 2 years have elapsed since the 
formal discontinuation of clinical development of the IMP. These documents should be retained 
for a longer period, however, if required by the applicable regulatory requirement(s) or by an 
agreement with UCB (CPMP/ICH/135/95, 2002 [Section 4.9.5]). The Investigator will contact 
UCB for authorization prior to the destruction of any study records or in the event of accidental 
loss or destruction of any study records. The Investigator will also notify UCB should he/she 
relocate or move the study-related files to a location other than that specified in the Sponsor’s 
trial master file. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 96 of 142 
13.6 
Audit and inspection 
The Investigator will permit study-related audits mandated by UCB, after reasonable notice, and 
inspections by domestic or foreign regulatory authorities. 
The main purposes of an audit or inspection are to confirm that the rights and well-being of the 
subjects enrolled have been protected, that enrolled subjects (ie, signing consent and undergoing 
study procedures) are appropriate for the study, and that all data relevant for the evaluation of the 
IMP have been processed and reported in compliance with the planned arrangements, the 
protocol, investigational site, and IRB/IEC SOPs, ICH-GCP, and applicable regulatory 
requirements. 
The Investigator will provide direct access to all study documents, source records, and source 
data. If an inspection by a regulatory authority is announced, the Investigator will immediately 
inform UCB (or designee). 
13.7 
Good Clinical Practice 
Noncompliance with the protocol, ICH-GCP, or local regulatory requirements by the 
Investigator, institution, institution staff, or designees of the Sponsor will lead to prompt action 
by UCB to secure compliance. Continued noncompliance may result in the termination of the 
site’s involvement in the study. 
14 
STATISTICS 
A description of statistical methods follows and will be described in more detail in the SAP. 
14.1 
Definition of analysis sets 
The following analysis sets were defined: 
• The Enrolled Set (ES) consists of all subjects who have given informed consent. 
• The Randomized Set (RS) consists of all randomized subjects.  
• The Safety Set (SS) consists of all randomized subjects who received at least 1 dose of the 
IMP. 
• The Full Analysis Set (FAS) consists of all randomized subjects who received at least 1 dose 
of the IMP and have valid measurement of the components of the primary efficacy variable 
at Baseline. 
• The Per-Protocol Set (PPS) will consist of all subjects in the RS who had no important 
protocol deviations affecting the primary efficacy variable. Important protocol deviations 
will be predefined and subjects with important protocol deviations will be evaluated during 
ongoing data cleaning meetings prior to unblinding of the data. Exclusions from the FAS will 
be considered important protocol deviations that also result in exclusion from the PPS. 
• The Pharmacokinetic Per-Protocol Set (PK-PPS) consists of all randomized subjects who 
received at least one dose of the IMP and provided at least one quantifiable plasma 
concentration post-dose without important protocol deviations that would affect the 
concentration. Exclusions from the FAS will be considered important protocol deviations that 
also result in exclusion from the PK-PPS. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 97 of 142 
• The COVID-19-free Set will consist of all subjects in the RS who had no COVID-19 impact 
up to the primary efficacy endpoint. This will be defined as subjects not having a COVID-19 
related important protocol deviation, nor having an impact based on the COVID-19 eCRF 
nor having an AE related to COVID-19, nor discontinuing due to COVID-19 up to the time 
of the primary endpoint. 
14.2 
General statistical considerations 
Summary statistics will consist of frequency tables for categorical variables. For continuous 
variables, summary statistics will consist of number of available observations, arithmetic mean, 
SD, median, minimum, and maximum unless stated otherwise. 
All statistical tests will be performed 2-sided at a 5% level of significance unless stated 
otherwise. 
14.3 
Planned efficacy analyses 
14.3.1 
Analysis of the primary and secondary efficacy variables 
A fixed sequence testing procedure will be applied for the primary and selected secondary 
variables. The testing procedure will control the family-wise type-I-error and will account for 
multiplicity. The family-wise error will be set to α=0.05 (2-sided).  
For each test, on each binary efficacy endpoint, the null hypothesis is that the conditional odds 
ratio is equal to one.  
H0: ORT1T2 = 1 
The alternative hypothesis is that the conditional odds ratio is not equal to one. 
HA: ORT1T2≠ 0  
For each test, on each continuous efficacy endpoint, the null hypothesis is that there is no 
difference between treatment groups.   
H0: T1 – T2 = 0 
The alternative hypothesis is that there is a difference between treatment groups. 
HA: T1 – T2 ≠ 0  
For the primary and secondary variables, the primary comparison is the bimekizumab 160mg sc 
Q4W vs placebo. Point estimates and 95% confidence intervals (CI) will be calculated. 
The testing starts with H1. If H1 can be rejected at α=0.05 (2-sided), the corresponding α will be 
passed on to the next test in the sequence and testing will continue. The testing will be stopped if 
a hypothesis cannot be rejected at α=0.05 (2-sided). 
The fixed sequence testing procedure of primary and secondary efficacy endpoints is shown in 
Figure 14-1. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 98 of 142 
Figure 14-1: Sequential testing procedure of primary/secondary efficacy 
endpoints (fixed sequence testing procedure) 
 
ACR50=American College of Rheumatology 50% response criteria; BKZ=bimekizumab; CfB=change from 
Baseline; H=hypothesis; HAQ-DI=Health Assessment Questionnaire-Disability Index; MDA=Minimal Disease 
Activity; PASI90=Psoriasis Area and Severity Index 90; PCS=Physical Component Summary; Q4W=every 
4 weeks; SF-36= Short-Form 36-item Health Survey; W=Week 
14.3.1.1 
Analysis of the primary efficacy variable 
The primary efficacy variable will be analyzed for all subjects in the RS. 
The primary endpoint is the ACR50 response at Week 16. The primary efficacy analysis will 
evaluate the composite estimand in the RS. The composite estimand combines the clinically 
meaningful improvement from Baseline in ACR50 response and not discontinuing treatment 
early. This composite estimand is similar to nonresponder imputation (NRI). 
The following 4 attributes describe the estimand that will be used to define the treatment effect 
of interest for the primary efficacy analysis: 
1. Population = Subjects enrolled according to the protocol-specified inclusion/exclusion 
criteria and randomized to IMP 
2. Subject-level outcome = ACR50 at Week 16 
3. Intercurrent event handling = An intercurrent event is defined as discontinuation of study 
treatment prior to Week 16. A composite strategy will be implemented in which a positive 
clinical outcome is defined as achieving ACR50 at Week 16 and not discontinuing study 
treatment through Week 16.  
4. Population-level summary measure = Conditional odds ratio comparing bimekizumab to 
placebo. 
As the ACR response is based on 7 different component scores, it is necessary to consider 
various data scenarios that could impact the calculation of response. The rules described here are 
applicable in the context of the calculation of ACR response and may differ from the rules 
applied for calculating and summarizing the components individually (some values may need to 
be imputed for component analysis but are not required here to evaluate ACR response).  
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 99 of 142 
The following rules will be applied prior to invoking any imputation analysis at the variable 
level: 
• If a subject has a component value that is equal to 0 at Baseline and the post-Baseline 
value is greater than or equal to 0, then the percent improvement for that component will 
be treated as 0 for purposes of ACR response calculations.  
• If a subject has component values that are missing at Baseline, then the percent 
improvement for that component will be treated as missing for purposes of ACR response 
calculations 
Observed data will be used to calculate ACR response where possible. In case of partial missing 
data where an observed response may be calculated, imputed data will not change the result. 
Missing data at Week 16 that are not preceded by an intercurrent event, and any data after an 
intercurrent event will be imputed as nonresponders. 
The statistical hypothesis for the ACR50 response at Week 16 is that the conditional odds ratio 
for ACR50 response in the bimekizumab treatment compared with placebo is equal to 1.  
A logistic regression model will be used to assess the treatment effect on ACR50 response at 
Week 16. The model will include fixed effects for treatment. The suitability of including the 
randomization stratification variables, prior TNFα exposure and region will be assessed, and will 
be added to the model if appropriate. Comparisons will be made using the 2-sided Wald test at a 
significance level of α=0.05 (ie, H1 Figure 14-1). The odds ratio vs placebo, p-value and the 
95% CI will be calculated. 
Any use of prohibited or rescue medications through Week 16 would constitute an important 
protocol deviation which would be accounted for when the sensitivity analysis based on the PPS 
is performed (see Section 14.3.1.1.1). 
14.3.1.1.1 
Supportive analyses 
Supportive analyses for the primary efficacy variable will be conducted: 
1. The analysis will be repeated based on the PPS to evaluate the effect of important protocol 
deviations on the analysis.  
2. The analyses will be repeated for all subjects in the FAS to evaluate the consistency between 
the RS and the more restrictive FAS. This analysis will only be performed if the number of 
subjects in RS and FAS are different. 
3. The primary comparison will also be repeated for all individual components of the 
ACR50 response to explore the effect of the signs and symptoms of the individual 
components on the composite endpoint. Since all ACR components are continuous variables 
(eg, change from Baseline in TJC), an analysis of covariance (ANCOVA) with treatment, 
prior TNFα exposure and region, as fixed effects and the Baseline value as covariate will be 
used for the analysis. Note as outlined above, some additional values may need to be imputed 
for component analysis which are not required to evaluate the overall ACR response. 
4. The analysis will be repeated using a modified composite estimand where intercurrent events 
are defined only as discontinuation due to AE or lack of efficacy. 
5. The analysis will be repeated using a treatment policy approach. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 100 of 142 
6. The analysis will be repeated using observed cases only. 
7. The analysis will be repeated using the COVID-free Set. 
Additional sensitivity and supportive analyses to evaluate varying assumptions related to the 
handling of missing data will also be performed and are described in Section 14.7. 
14.3.1.2 
Analyses of the secondary efficacy variables 
The secondary efficacy variables will be analyzed for all subjects in the RS.  
All binary variables that are part of the testing hierarchy are given below: 
• PASI90 responders at Week 16 will be analyzed to evaluate the composite estimand. The 
composite estimand combines the clinically meaningful improvement from Baseline in 
PASI90 response and not discontinuing treatment early. 
• The proportion of subjects achieving MDA status at Week 16 will be analyzed to evaluate 
the composite estimand. The composite estimand combines (1) achieving the MDA status 
with (2) not discontinuing treatment early. 
The statistical hypothesis for the binary variables at Week 16 is that the conditional odds ratio for 
binary variable in the bimekizumab treatment compared with placebo groups is equal to 1. 
The binary variables will be analyzed using the same analysis methods as used for the primary 
variable (Section 14.3.1.1). 
All continuous variables that are part of the testing hierarchy are given below: 
• Change from Baseline in HAQ-DI at Week 16.   
• Change from Baseline in SF-36 PCS score at Week 16.   
Continuous variables will be analyzed to evaluate the hypothetical estimand as defined below: 
1. Population = Subjects enrolled according to the protocol-specified inclusion/exclusion 
criteria and randomized to IMP 
2. Subject level outcome = variable as stated in Section 4.2.1  
3. Intercurrent event handling = An intercurrent event is defined as discontinuation of study 
treatment prior to Week 16. A hypothetical strategy for addressing intercurrent events will be 
implemented. This estimand targets the treatment difference in a scenario where withdrawal 
from study treatment does not occur, such that outcomes for subjects without an intercurrent 
event are as observed, and outcomes for subjects with an intercurrent event are treated as 
though they had completed the randomized study treatment through Week 16. A multiple 
imputation strategy will be used to impute data following an intercurrent event. 
4. Population-level summary measure = the difference in the adjusted means between 
bimekizumab 160mg Q4W and placebo.  
Any missing data at Week 16 that is not preceded by an intercurrent event (ie, discontinuation of 
study medication) will also be imputed based on a predefined MI model. In MI, the missing 
value is replaced by a set of plausible values, where each value is a Bayesian draw from the 
conditional distribution of the missing data given the observed data. Intermittent missing data 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 101 of 142 
will be imputed using the MCMC method, followed by monotone regression for monotone 
missing data. 
The statistical model for continuous endpoints for the comparison of bimekizumab and placebo 
will be an ANCOVA model with treatment, prior TNFα exposure and region as fixed effects and 
the Baseline value as covariate. The statistical hypothesis for the continuous variables at 
Week 16 is that the treatment difference between the bimekizumab treatment group and placebo 
is equal to 0. 
All secondary efficacy variables will also be summarized based on observed case data as well as 
multiple imputation using the modified composite estimand for binary variables. 
Variables that are included in the hierarchy will additionally be rerun using the COVID-free Set. 
14.3.2 
Analyses of the other efficacy variables 
All other efficacy variables will be analyzed for all subjects in the RS.  
Generally, the estimand structure for binary other efficacy variables is as described below. Note 
that further details will be provided in the SAP. 
1. Population = Subjects enrolled according to the protocol-specified inclusion/exclusion 
criteria and randomized to IMP. 
2. Subject-level outcome = The given variable and time point being summarized (eg, ACR20 at 
Week 8) 
3. Intercurrent event handling = An intercurrent event is defined as discontinuation of study 
treatment prior to the time point being summarized. A composite strategy will be 
implemented in which a positive clinical outcome is defined as achieving the given variable 
at the specified time point and not discontinuing study treatment through that time point.   
4. Population-level summary measure = Unadjusted proportion of responders 
Any missing data that are not preceded by an intercurrent event as described above will be 
imputed based on NRI as described for the primary and secondary efficacy variables. 
Continuous variables will be summarized using descriptive statistics by treatment group and by 
each visit. Generally, the estimand structure for continuous other efficacy variables is as 
described below. Note that further details will be provided in the SAP. 
1. Population = Subjects enrolled according to the protocol-specified inclusion/exclusion 
criteria and randomized to IMP 
2. Subject-level outcome = The given variable and time point being summarized (eg, change 
from Baseline in HAQ-DI at Week 8) 
3. Intercurrent event handling = An intercurrent event is defined as discontinuation of study 
treatment prior to the time point being summarized. A hypothetical strategy will be 
implemented in which outcomes for subjects without an intercurrent event are as observed at 
the given time point, and outcomes for subjects with an intercurrent event are treated as 
though they had completed the randomized study treatment through the time point being 
summarized. A multiple imputation strategy will be used to impute data following an 
intercurrent event.  
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 102 of 142 
4. Population-level summary measure = Unadjusted mean. 
Any missing data that are not preceded by an intercurrent event as described above will be 
imputed based on a predefined multiple imputation model as described for continuous secondary 
efficacy variables. 
Other binary and continuous efficacy variables will also be summarized based on observed case 
(OC) data (ie, subjects with missing data or who have prematurely discontinued study treatment 
are treated as missing). Further, binary outcomes will be summarized using the modified 
composite estimand. 
The time to ACR20/50/70 response will be estimated and presented using the Kaplan Meier 
product limit method for each treatment. Time to a given response will be defined as the time in 
days from Baseline until the first date when the response is achieved. Subjects who discontinue 
study treatment prior to achieving a response will be censored at the date of study treatment 
discontinuation. The median time to response, including the 2-sided 95% CI, will be calculated 
for each treatment. Between group differences will be analyzed using a log-rank statistic. 
The time to ACR20/50/70 endpoints will be analyzed using OC data. All other efficacy variables 
will be analyzed based on imputed and on OC data. 
14.3.3 
Subgroup analyses 
Subgroup analyses will be performed on the ACR50 response and the PASI90 response at 
Week 16. The following variables for subgroup analyses will be defined:  
• Age (<45 years of age, ≥45 years of age) 
• Gender (male, female) 
• Disease duration (<1 years, ≥1 years) 
• Region (eg, Asia, Eastern Europe, North America, Western Europe) 
• Race 
• Weight at Baseline (≤100kg, >100kg)  
• hs-CRP at Baseline (<6mg/L, ≥6mg/L) 
• Prior TNF exposure (intolerance to TNFα, inadequate response to 1 TNFα, inadequate 
response to 2 TNFα inhibitors) 
• Prior conventional disease-modifying antirheumatic drugs (cDMARDs) (0, 1, ≥2) 
• Concomitantly receiving cDMARDs versus no concomitant cDMARDs  
• Concomitantly receiving MTX versus no concomitant MTX 
• PSO affected BSA at Baseline (<3%, ≥3% to ≤10%, >10%) 
• BASDAI at Baseline (≤4, >4) 
• Anti-bimekizumab antibody status (positive, negative) 
• HLA-B27 status (positive, negative) 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 103 of 142 
14.4 
Planned safety analyses 
14.4.1 
Safety analyses 
Safety variables will be analyzed for all subjects in the SS. 
Adverse events will be coded according to the Medical Dictionary for Regulatory Activities 
(MedDRA® 19.0). Adverse events with an onset date on or after the date of first IMP 
administration and up to 20 weeks after the last (most recent) dose of IMP will be defined as 
TEAEs. Treatment-emergent AEs will be summarized descriptively by treatment group, primary 
system organ class, high-level term, and preferred term. Additional tables will summarize 
TEAEs leading to withdrawal from IMP, TEAEs by intensity and relationship to IMP. 
Treatment-emergent AEs leading to withdrawal from both IMP or the study, serious TEAEs, 
TEAEs of special interest, TEAEs of special monitoring and deaths will be also be tabulated and 
listed. TEAEs adjusted for exposure will also be presented.  
When analyzing categorical data, the number and percentage of subjects in each category will be 
presented by treatment group. In addition, shift tables may be used to evaluate the number and 
percentage of subjects having a different post-Baseline status when compared to their baseline 
status. 
Laboratory value (including markedly abnormal values), urinary values, vital signs, ECGs, 
eC-SSRS, and extent of exposure will be presented descriptively by treatment group. Definitions 
for markedly abnormal laboratory values will be provided in the SAP. 
14.5 
Other planned analyses 
14.5.1 
Pharmacokinetics analyses 
Pharmacokinetic variables will be analyzed for all subjects in the PK-PPS.  
Bimekizumab plasma concentrations will be summarized for each treatment at each scheduled 
visit. 
The relationship between bimekizumab plasma concentrations and efficacy response (for 
example ACR20/50/70) and/or safety endpoints may be explored via a graphical and/or a model 
based (PK-PD) approach. The data may also be combined with that from other bimekizumab 
studies. The details of such analysis will be described separately in a data analysis plan, and the 
analysis itself will be reported separately from the CSR.   
14.5.2 
Immunological analyses 
Anti-bimekizumab antibodies will be assessed using a tiered approach: screening, confirmatory, 
and titer assays will be used. Anti-bimekizumab antibodies (including positivity) will be 
summarized by treatment at each scheduled visit at which samples are collected.  
14.6 
Handling of protocol deviations 
Important protocol deviations are deviations from the protocol which potentially could have a 
meaningful impact on study conduct or on the primary efficacy, key safety, or PK outcomes for 
an individual subject. The criteria for identifying important protocol deviations will be defined 
within the appropriate protocol-specific document. Important protocol deviations will be 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 104 of 142 
reviewed as part of the ongoing data cleaning process, and all important deviations will be 
identified and documented prior to unblinding to confirm exclusion from analysis sets. 
14.7 
Handling of dropouts or missing data 
The primary method for assessing the efficacy variables will be the composite estimand 
approach to handling missing data that is similar to NRI. The sensitivity of results to the 
approach for handling missing data will be evaluated via supportive analyses using different 
missing data mechanisms. 
In instances where MI is used, the missing value is replaced by a set of plausible values, where 
each value is a Bayesian draw from the conditional distribution of the missing data given the 
observed data. Intermittent missing data will be imputed using the MCMC method, followed by 
regression for monotone missing data. The multiple imputation procedures planned for efficacy 
analyses are based on an assumption of data missing at random (MAR).  
The following sensitivity analyses for the primary efficacy variable and for those secondary 
efficacy variables that are part of the hierarchical testing will be conducted: 
1.  Multiple imputation as described above will be performed using the modified composite 
estimand. The definition of an intercurrent event is changed from all treatment 
discontinuation, to discontinuation of treatment due to AE or lack of efficacy.  
2. A tipping point analysis will be performed to evaluate missingness assumptions. The tipping 
point analysis will be performed on the monotone missing data and only if the primary 
analysis is significant at α=0.05. Various delta adjustments will be made to the assumed 
responses on the monotone missing data in each treatment group independently with various 
degrees of plausibility. It will include scenarios where subjects who have missing data and 
are randomized to bimekizumab have a lower probability of response compared to subjects 
who have missing data and were randomized to placebo. For binary variables this includes 
the worst case scenario where subjects who have missing data and are randomized to 
bimekizumab are considered nonresponders. The goal of the tipping point analysis is to 
systematically vary assumptions until there is no evidence of a treatment effect (if possible). 
The plausibility of such required delta adjustment will then be assessed. Details will be 
provided in the SAP.  
3. The treatment policy strategy for addressing intercurrent events will be considered. This will 
be based on an analysis in which all available data at Week 16 regardless of the occurrence 
of intercurrent events will be considered. This analysis will use the same models specified for 
the primary and secondary analyses where subjects are analyzed according to their 
randomized treatment, even if they discontinued study treatment for any reason prior to 
Week 16 and were no longer on the randomized study treatment when the assessment was 
performed at Week 16. Even though efforts will be made to collect the primary outcome data 
for all subjects at Week 16, there may still be some subjects for whom Week 16 efficacy data 
cannot be obtained. In this case, missing data will be imputed using MI under the assumption 
of MAR. Results will be combined into a single inference using Rubin's rule. It should be 
noted that this measures something different from the primary analysis and could be 
confounded by placebo subjects who withdraw and are subsequently on another active 
medication at the time of the Week 16 assessment. Therefore, the results of this analysis 
should be interpreted in the appropriate context. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 105 of 142 
4. An additional sensitivity analysis will be based on observed data only for subjects who are 
still on the randomized treatment at Week 16. Subjects with missing data or who have 
prematurely discontinued study treatment will be treated as missing. The same analysis 
procedure described in the main efficacy analysis will be used. 
Additional details on these sensitivity analyses will be provided in the SAP. 
14.8 
Planned interim analysis and data monitoring 
14.8.1 
Data monitoring 
A DMC will be reviewing safety data on an ongoing basis. The DMC membership includes 
experienced clinicians and a statistician, all of whom have expertise in clinical studies. Further 
details are specified in the DMC Charter.  
Cardiovascular and Neuropsychiatric Adjudication Committees will also periodically review 
data from this study. Details are provided in the Cardiovascular Adjudication Committee and 
Neuropsychiatric Adjudication Committee charters. 
Other adjudication committees may be added as necessary. 
Both Data Monitoring and Adjudication Committee members may not participate in the study as 
principal or co-Investigators, or as study subject care physicians and must not be members of the 
study team at UCB or the conducting CRO. The duration of membership for the committees will 
be inclusive of planned analyses for PA0011. 
14.8.2 
Interim analysis 
One interim analysis will be performed after all randomized subjects have completed the 
Double-Blind Treatment Period at Week 16.  
The purpose of the Week 16 interim analysis is to perform a comprehensive evaluation of all 
available double-blind data for the 2 treatment arms and to prepare a regulatory submission for a 
marketing authorization application based on this analysis. 
For the Week 16 interim analysis, the database will be locked, and the treatment codes will be 
made available to UCB personnel with exception of operational staff working on the study. An 
interim report will be written. The Investigators and subjects will remain blind to the assigned 
bimekizumab dosing regimen until the final analysis is completed. 
The interim analysis will evaluate the primary and secondary efficacy variables, as well as all 
other efficacy, safety, and PK variables up to Week 16 according to the statistical methods 
specified in the SAP. No formal alterations to the further study conduct (eg, stopping rules, 
sample size re-estimation, or changes to eligibility criteria) are planned for this interim analysis. 
To ensure blinding of Investigators and subjects, a blinding plan will be written to evaluate the 
potential bias of the Active Treatment-Blind period, define blinded and unblinded teams, and 
describe the process of interim results generation and dissemination. The plan will be finalized 
prior to the lock of the database at the interim analysis. 
14.9 
Determination of sample size 
Approximately 390 subjects will be randomly assigned in a 2:1 ratio to the following treatment 
groups: bimekizumab 160mg sc Q4W (260 subjects) and placebo (130 subjects).  
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 106 of 142 
The primary efficacy analysis is based on the primary comparison of bimekizumab versus 
placebo for ACR50 response at Week 16. 
All sample size and power calculations were done at a significance level of 0.05. 
All sample size and power calculations were performed using the software nQuery Advisor® 7.0. 
14.9.1 
Power calculation for primary endpoint 
The sample size assumptions for bimekizumab vs placebo are based on the ACR50 response data 
in the subgroup of TNFα-IR patients from the Phase 2b bimekizumab study in a mixed prior 
TNFα therapy population of subjects with moderate to severe PsA (PA0008). Sample size 
calculations for a TNFα-IR population are also based on ACR50 responses at Week 16 in the 
SPIRIT-P2 study.  
Observed ACR50 at Week 12 results in the PA0008 TNFα-IR populations were in a small 
number of subjects; bimekizumab 160mg (n=7), 320mg (n=8), and 320mg (initial dose) plus 
160mg (n=8) and ranged from 14.3% to 37.5%.  
The ixekizumab Phase 3 study SPIRIT–P2 is conducted on a similar patient population to that in 
this study and showed a 35% (n=122) ACR50 response at Week 16. Therefore, taking into 
account the range of ACR50 responses at Week 12 in PA0008, the estimated ACR50 response at 
Week 16 in the bimekizumab 160mg sc Q4W group is conservatively assumed to be 26%.  
For placebo, a similar approach as above is used. In the PA0008 TNFα-IR population, an 
ACR50 response of 11.1% (n=9) was observed at Week 12. The observed placebo 
ACR50 response at Week 16 was less than 10% in the SPIRIT-P2 study (n=118). Therefore, the 
estimated ACR50 response at Week 16 in the placebo group is assumed to be 10%. 
The sample size for showing statistical superiority of bimekizumab vs placebo was calculated 
using a 2-sided 2-sample Chi-square test with continuity correction (Fleiss et al, 1980). 
Assuming 260 subjects in the bimekizumab group and 130 subjects in the placebo group, the test 
for detecting statistical superiority of bimekizumab 160mg vs placebo based on ACR50 response 
at Week 16 has 96% power to detect a true treatment difference of 16% (odds ratio of 3.16).  
14.9.2 
Power calculations for secondary endpoints 
The assumptions for power calculations of the secondary endpoints included in the hierarchy and 
for which supporting data are available, in the TNFα-IR population are based on the results of 
PA0008 and the SPIRIT-P2 studies. All power calculations for binary endpoints were performed 
using a 2-sided 2-sample Chi-square test with continuity correction (Fleiss et al, 1980). All 
power calculations for continuous endpoints were performed using a 2-sided 2-group 
Satterthwaite t-test (Moser et al, 1989). 
For PASI90 response at Week 16, a PASI90 response at Week 12 of 38% (N=122), from the 
SPIRIT-P2 study is assumed. The PASI90 response at Week 12 in the bimekizumab 160mg 
group is 50.0% (n=8) in the subgroup analysis of the TNFα-IR patients. Placebo PASI90 
response at Week 16 is based on SPIRIT-P2 data (6.0% at Week 12). However, for this endpoint 
the placebo response is rounded to 10%. With those assumptions, the endpoint has 99% power to 
detect a treatment difference of 28% (odds ratio 5.52) at an assumed 50% of subjects with 
BSA ≥3% of the planned sample size. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 107 of 142 
For the change from Baseline in HAQ-DI at Week 16, based on data from the TNFα-IR 
population in SPIRIT-P2 Week 12 as well as Week 12 and Week 16 data from the PA0008 and 
PsA001 studies respectively, estimates of the SD in the active treatment and placebo groups 
are 0.71. A 2-group Satterthwaite t-test with a 0.050 2-sided significance level will have 85% 
power to detect a difference of 0.23 in the mean change from Baseline in HAQ-DI at Week 16 
between bimekizumab treatment and placebo assuming a sample size of 390 subjects 
randomized 2:1. 
For the change from Baseline in PCS score of SF-36 at Week 16, based on data from the TNFα-
IR population in SPIRIT-P2 where estimates of the SD in the active treatment and placebo 
groups at Week 12 are ixekizumab Q4W (SD=11.95) and placebo (SD=12.15). A two-group 
Satterthwaite t-test with a 0.050 2-sided significance level will have 89% power to detect a 
difference in means of 4.4 change from Baseline in SF-36 PCS score at Week 16 between the 
bimekizumab and placebo treatment groups with a sample size of 390 subjects randomized 2:1. 
For MDA at Week 16, it is assumed that 5% of the placebo subjects achieve MDA at Week 16 
(SPIRIT-P2 Week 12). Given the planned sample size and using a 2-sided 2-sample Chi-square 
test with continuity correction this study has 92% power to detect an absolute difference in MDA 
response at Week 16 of 12% (odds ratio of 3.892) with a total sample size of 390 patients. 
15 
ETHICS AND REGULATORY REQUIREMENTS 
15.1 
Informed consent 
Subject’s informed consent must be obtained and documented in accordance with local 
regulations, ICH-GCP requirements, and the ethical principles that have their origin in the 
principles of the Declaration of Helsinki. 
Prior to obtaining informed consent, information should be given in a language and at a level of 
complexity understandable to the subject in both oral and written form by the Investigator (or 
designee). Each subject will have the opportunity to discuss the study and its alternatives with 
the Investigator. 
Prior to participation in the study, the Informed Consent form should be signed and personally 
dated by the subject and by the person who conducted the informed consent discussion 
(Investigator or designee). The subject must receive a copy of the signed and dated Informed 
Consent form. As part of the consent process, each subject must consent to direct access to 
his/her medical records for study-related monitoring, auditing, IRB/IEC review, and regulatory 
inspection. 
If the Informed Consent form is amended during the study, the Investigator (or the Sponsor, if 
applicable) must follow all applicable regulatory requirements pertaining to the approval of the 
amended Informed Consent form by the IRB/IEC and use of the amended form. 
All studies conducted at centers in the US must include the use of a Health Insurance Portability 
and Accountability Act Authorization form. 
The subject may withdraw his/her consent to participate in the study at any time. A subject is 
considered as enrolled in the study when he/she has signed the Informed Consent form. An eCRF 
must not be started, nor may any study specific procedure be performed for a given subject, 
without having obtained his/her written consent to participate in the study. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 108 of 142 
15.2 
Subject identification cards 
Upon signing the Informed Consent form, the subject will be provided with a subject 
identification card in the language of the subject. The Investigator will fill in the subject 
identifying information and medical emergency contact information. The Investigator will 
instruct the subject to keep the card with him/her at all times. 
15.3 
Institutional Review Boards and Independent Ethics 
Committees 
The study will be conducted under the auspices of an IRB/IEC, as defined in local regulations, 
ICH-GCP, and in accordance with the ethical principles that have their origin in the Declaration 
of Helsinki. 
The Investigator/UCB will ensure that an appropriately constituted IRB/IEC that complies with 
the requirements of the current ICH-GCP version or applicable country-specific regulations will 
be responsible for the initial and continuing review and approval of the clinical study. Prior to 
initiation of the study, the Investigator/UCB will forward copies of the protocol, Informed 
Consent form, IB, Investigator’s curriculum vitae (if applicable), advertisement (if applicable), 
and all other subject-related documents to be used for the study to the IRB/IEC for its review and 
approval. 
Before initiating a study, the Investigator will have written and dated full approval from the 
responsible IRB/IEC for the protocol. 
The Investigator will also promptly report to the IRB/IEC all changes in the study, all 
unanticipated problems involving risks to human subjects or others, and any protocol deviations, 
to eliminate immediate hazards to subjects. 
The Investigator will not make any changes in the study or study conduct without IRB/IEC 
approval, except where necessary to eliminate apparent immediate hazards to the subjects. For 
minor changes to a previously approved protocol during the period covered by the original 
approval, it may be possible for the Investigator to obtain an expedited review by the IRB/IEC as 
allowed. 
As part of the IRB/IEC requirements for continuing review of approved studies, the Investigator 
will be responsible for submitting periodic progress reports to the IRB/IEC (based on IRB/IEC 
requirements), at intervals appropriate to the degree of subject risk involved, but no less than 
once per year. The Investigator should provide a final report to the IRB/IEC following study 
completion. 
UCB (or its representative) will communicate safety information to the appropriate regulatory 
authorities and all active Investigators in accordance with applicable regulatory requirements. 
The appropriate IRB/IEC will also be informed by the Investigator or the Sponsor, as specified 
by the applicable regulatory requirements in each concerned country. Where applicable, 
Investigators are to provide the Sponsor (or its representative) with evidence of such IRB/IEC 
notification. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 109 of 142 
15.4 
Subject privacy 
UCB staff (or designee) will affirm and uphold the subject’s confidentiality. Throughout this 
study, all data forwarded to UCB (or designee) will be identified only by the subject number 
assigned at Screening. 
The Investigator agrees that representatives of UCB, its designee, representatives of the relevant 
IRB/IEC, or representatives of regulatory authorities will be allowed to review that portion of the 
subject’s primary medical records that directly concerns this study (including, but not limited to, 
laboratory test result reports, ECG reports, admission/discharge summaries for hospital 
admissions occurring during a subject’s study participation, and autopsy reports for deaths 
occurring during the study). 
15.5 
Protocol amendments 
Protocol changes may affect the legal and ethical status of the study and may also affect the 
statistical evaluations of sample size and the likelihood of the study fulfilling its primary 
objective. 
Significant changes to the protocol will only be made as an amendment to the protocol and must 
be approved by UCB, the IRB/IEC, and the regulatory authorities (if required), prior to being 
implemented. 
16 
FINANCE, INSURANCE, AND PUBLICATION 
Insurance coverage will be handled according to local requirements. 
Finance, insurance, and publication rights are addressed in the Investigator and/or CRO 
agreements, as applicable. 
17 
REFERENCES 
Antoni CE, Kavanaugh A, Kirkham B, Tutuncu Z, Burmester GR, Schneider U, et al. Sustained 
benefits of infliximab therapy for dermatologic and articular manifestations of psoriatic arthritis: 
results from the infliximab multinational psoriatic arthritis controlled trial (IMPACT). Arthritis 
Rheum. 2005a;52:1227-36. 
Antoni C, Krueger GG, de Vlam K, Birbara C, Beutler A, Guzzo C, et al. Infliximab improves 
signs and symptoms of psoriatic arthritis: results of the IMPACT 2 trial. Ann Rheum Dis. 
2005b;64:1150–57. 
Carpenter JR, Kenward MG. 2013. Multiple imputation and its application. John Wiley & Sons, 
345 pp.  
Cella D, Wilson H, Shalhoub H, et al. Content validity and psychometric evaluation of 
Functional Assessment of Chronic Illness Therapy-Fatigue in patients with psoriatic arthritis. J 
Patient Rep Outcomes. 2019;3(1):5. 
CHMP/EWP/438/04. Guideline of Clinical Investigation of Medicinal Products for the 
Treatment of Psoriatic Arthritis. 14 December 2006. 
Coates LC, FitzGerald O, Mease PJ, et al. Development of a disease activity and responder index 
for psoriatic arthritis – Report of the Psoriatic Arthrits Module at OMERACT 11. J Rheumatol 
2014;41:782-91. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 110 of 142 
Coates LC, Fransen J, Helliwell PS. Defining minimal disease activity in psoriatic arthritis: a 
proposed objective target for treatment. Ann Rheum Dis. 2010;69:48–53. 
Coates LC, Gladman DD, Nash P, et al. Secukinumab provides sustained PASDAS-defined 
remission in psoriatic arthritis and improves health-related quality of life in patients achieving 
remission: 2-year results from the Phase III FUTURE 2 study. Arthritis Res Ther. 
2018;20(1):272. doi: 10.1186/s13075-018-1773-y. 
Cochran WG. Some Methods for Strengthening the Common χ2 Tests. Biometrics. 
1954;10(4):417–51. 
Feldman SR, Krueger GG. Psoriasis assessment tools in clinical trials. Ann Rheum Dis 
2005;64(Suppl II):ii65–ii68. 
Felson DT, Anderson J, Boers M, Bombardier C, Chernoff M, Fried B. The American college of 
rheumatology preliminary core set of disease activity measures for rheumatoid arthritis clinical 
trials. Arthritis & Rheum. 1993;36(6):729-740. 
Fernández-Sueiro JL, Willisch A, Pertega-Díaz S, Tasende JA, Fernández-Lopez C, Galdo F, et 
al. Evaluation of ankylosing spondylitis spinal mobility measurements in the assessment of 
spinal involvement in psoriatic arthritis. Arthritis Rheum. 2009;61:386-92. 
Fleiss JL, Tytun A, Ury SHK. A simple approximation for calculating sample sizes for 
comparing independent proportions. Biometrics. 1980;36:343-6. 
Fujishima S, Watanabe H, Kawaguchi M, Suzuki T, Matsukura S, Homma T, et al. Involvement 
of IL-17F via the induction of IL-6 in psoriasis. Arch Dermatol Res. 2010;302:499-505. 
Garrett S, Jenkinson T, Kennedy LG, Whitelock H, Gaisford P, Calin A. A new approach to 
defining disease status in ankylosing spondylitis: the Bath Ankylosing Spondylitis Disease 
Activity Index. J Rheumatol. 1994;21(12):2286 91. 
Genovese MC, Mease PJ, Thomson GT, Kivitz AJ, Perdok RJ, Weinberg MA, et al. Safety and 
efficacy of adalimumab in treatment of patients with psoriatic arthritis who had failed disease 
modifying antirheumatic drug therapy. J Rheumatol. 2007;34:1040–50. 
Genovese MC, Van den Bosch F, Roberson SA, Bojin S, Biagini IM, Ryan P, et al. LY2439821, 
a humanized anti-interleukin-17 monoclonal antibody, in the treatment of patients with 
rheumatoid arthritis: a phase I randomized, double-blind, placebo-controlled, proof-of-concept 
study. Arthritis Rheum. 2010;62:929-39. 
Gladman DD. Clinical features and diagnostic considerations in psoriatic arthritis. Rheum Dis 
Clin North Am. 2015;41(4):569-79 
Gladman DD, Mease PJ, Cifaldi MA, Perdok RJ, Sasso E, Medich J. Adalimumab improves 
joint-related and skin-related functional impairment in patients with psoriatic arthritis: patient 
reported outcomes of the Adalimumab Effectiveness in Psoriatic Arthritis Trial. Ann Rheum Dis. 
2007;66:163–68. 
Gossec L, de Wit M, Klitz U, Braun J, Kalyoncu U, Scrivo R, et al. A patient-derived and 
patient-reported outcome measure for assessing psoriatic arthritis: elaboration and preliminary 
validation of the Psoriatic Arthritis Impact of Disease (PsAID) questionnaire, a 13-country 
EULAR initiative. Ann Rheum Dis. 2014;73:1012-19.  
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 111 of 142 
Gottlieb A, Menter A, Mendelsohn A, Shen Y-K, Li S, Guzzo C, et al. Ustekinumab, a human 
interleukin 12/23 monoclonal antibody, for psoriatic arthritis: randomised, double-blind, 
placebo-controlled, crossover trial. Lancet. 2009;373:633-40. 
Harper EG, Guo C, Rizzo H, Lillis JV, Kurtz SE, Skorcheva I, et al. Th17 cytokines stimulate 
CCL20 expression in keratinocytes in vitro and in vivo: implications for psoriasis pathogenesis. 
J Invest Dermatol. 2009;129:2175 83. 
Healy PJ, Helliwell PS. Measuring dactylitis in clinical trials: Which is the best instrument to 
use? J Rheumatol. 2007;34:1302-6. 
Heuft-Dorenbosch L, Spoorenberg A, van Tubergen A, Landewé R, van der Tempel H, 
Mielants H, et al. Assessment of enthesitis in ankylosing spondylitis. Ann Rheum Dis. 
2003;62:127-32. 
Helliwell PS, Firth J, Ibrahim GH, Melsom RD, Shah I, Turner DE. Development of an 
assessment tool for dactylitis in patients with psoriatic arthritis. J Rheumatol. 2005;32:1745-50. 
Hueber W, Patel DD, Dryja T, Wright AM, Koroleva I, Bruin G, et al. Effects of AIN457, a fully 
human antibody to interleukin-17A on psoriasis, rheumatoid arthritis, and uveitis. Sci Transl 
Med. 2010;2:52-72. 
Johansen C, Usher PA, Kjellerup RB, Lundsgaard D, Iversen L, Kragballe K. Characterization of 
the interleukin-17 isoforms and receptors in lesional psoriatic skin. Br J Dermatol. 
2009;160:319-24. 
Kavanaugh A, Antoni C, Krueger GG, Yan S, Bala M, Dooley LT, et al. Infliximab improves 
health related quality of life and physical function in patients with psoriatic arthritis. Ann Rheum 
Dis. 2006;65:471–77. 
Kavanaugh A, McInnes I, Mease P, Krueger GG, Gladman D, Gomez-Reino J, et al. 
Golimumab, a new human tumor necrosis factor alpha antibody, administered every four weeks 
as a subcutaneous injection in psoriatic arthritis: twenty-four–week efficacy and safety results of 
a randomized, placebo-controlled study. Arthritis Rheum. 2009;60:976 86. 
Kavanaugh A, van der Heijde D, McInnes IB, Mease P, Krueger GG, Gladman DD, et al. 
Golimumab in psoriatic arthritis: one-year clinical efficacy, radiographic, and safety results from 
a phase III, randomized, placebo controlled trial. Arthritis Rheum. 2012;64:2504-17. 
Kavanaugh A, McInnes I, Mease P, Hall S, Chinoy H, Kivitz AJ, et al. Efficacy of subcutaneous 
secukinumab in patients with active psoriatic arthritis stratified by prior tumor necrosis factor 
inhibitor use: results from the randomized placebo-controlled FUTURE 2 study. J Rheum. 
2016;43:9. 
Lee S, Mendelsohn A, Sarnes E. The burden of psoriatic arthritis: a literature review from a 
global health systems perspective. P T 2010;35:680-9. 
Leonardi C, Matheson R, Zachariae C, Cameron G, Li L, Edson-Heredia E, et al. 
Anti-interleukin-17 monoclonal antibody ixekizumab in chronic plaque psoriasis. N Engl J Med. 
2012;366:1190-9. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 112 of 142 
Maksymowych WP, Mallon C, Morrow S, Shojania K, Olszynski WP, Wong RL, et al. 
Development and validation of the Spondyloarthritis Research Consortium of Canada 
(SPARCC) Enthesitis Index. Ann Rheum Dis. 2009;68(6):948-953. 
Maruish ME, editor. User’s manual for the SF-36v2 Health Survey. 3rd ed. Lincoln, RI: 
QualityMetric Incorporated; 2011. 
McHugh NJ, Balachrishnan C, Jones SM. Progression of peripheral joint disease in psoriatic 
arthritis: a 5-year prospective study. Rheumatology. 2003;42:778–83. 
McInnes IB, Mease PJ, Kirkham B, Kavanaugh A, Ritchlin CT, Rahman P, et al. Secukinumab, 
a human anti-interleukin-17A monoclonal antibody, in patients with psoriatic arthritis 
(FUTURE 2): a randomised, double-blind, placebo-controlled, phase 3 trial. Lancet. 
2015;386:1137-46.  
McInnes IB, Sieper J, Braun J, Emery P, van der Heijde D, Isaacs JD, et al. Efficacy and safety 
of secukinumab, a fully human anti interleukin-IL17A monoclonal antibody, in patients with 
moderate-to-severe psoriatic arthritis: a 24-week, randomised, double-blind, placebo-controlled, 
phase II proof-of-concept trial. Ann Rheum Dis. 2014;73:349-56. 
Mease PJ. Measures of psoriatic arthritis. Arthritis Care & Research 2011;63(S11):S64-85. 
Mease PJ, Gladman DD, Ritchlin CT, Ruderman EM, Steinfeld SD, Choy EH, et al. 
Adalimumab for the treatment of subjects with moderately to severely active psoriatic arthritis: 
results of a double-blind, randomized, placebo controlled trial. Arthritis Rheum. 
2005;52:3279-89. 
Mease PJ, Kivitz AJ, Burch FX, Siegel EL, Cohen SB, Ory P, et al. Etanercept treatment of 
psoriatic arthritis: safety, efficacy, and effect on disease progression. Arthritis Rheum. 
2004;50:2264–72. 
Mease PJ, McInnes IB, Kirkham B, Kavanaugh, A, Rahman, P, van der Heijde D, et al. 
Secukinumab inhibition of Interleukin-17A in patients with psoriatic arthritis. N Engl J Med. 
2015;373:1329-39. 
Moser, BK; Stevens, GR; Watts, CL. The Two-Sample T Test Versus Satterthwaite's 
Approximate F Test. Communication in Statistics- Theory and Methods 18(11):3963-3975 ·  
Mundt JC, Greist JH, Gelenberg AJ, Katzelnick DJ, Jefferson JW, Modell JG. Feasibility and 
Validation of a Computer-Automated Columbia-Suicide severity Rating Scale Using Interactive 
Voice Response Technology. J Psychiatr Res. 2010;44(16):1224-8. 
Ogdie A, Weiss P. The Epidemiology of Psoriatic Arthritis. Rheum Dis Clin North Am. 
2015;41(4):545-68. 
Papp KA, Leonardi C, Menter A, Ortonne JP, Krueger JG, Kricorian G, et al. Brodalumab, an 
anti–interleukin-17–receptor antibody for psoriasis. N Engl J Med. 2012;366:1181-9. 
Posner K, Brown GK, Stanley B, Brent DA, Yershova KV, Oquendo MA, et al. The 
Columbia-Suicide Severity Rating Scale: initial validity and internal consistency findings from 
three multisite studies with adolescents and adults. Am J Psychiatry. 2011;168(12):1266-77. 
Raychaudhuri SP, Raychaudhuri SK, Genovese MC. IL-17 receptor and its functional 
significance in psoriatic arthritis. Mol Cell Biochem. 2012;359:419–29. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 113 of 142 
Reilly MC, Zbronzek AS, Dukes EM. The Validity and Reproducibility of a Work Productivity 
and Activitiy Impairment Instrument. PharmacoEconomics. 1993:4(5):353-365. 
Salaffi F, Carotti M, Gasparini S, INtorcia M, Grassi W. The health-related quality of life in 
rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis: a comparison with a selected 
sample of healthy people. Health Qual Life Outcomes. 2009;7:25. 
van Tubergen A, Black PM, Coteur G. Are patient-reported outcome instruments for ankylosing 
spondylitis fit-for-purpose for the axial spondyloarthritis patient? A Qualitative and 
Psychometric Analysis. Rheum. 2015;54:1842-51. 
Watanabe H, Kawaguchi M, Fujishima S, Ogura M, Matsukura S, Takeuchi H, et al. Functional 
characterization of IL-17F as a selective neutrophil attractant in psoriasis. J Invest Dermatol. 
2009;129:650-6. 
Woodworth T, Furst DE, Alten R, Bingham C, Yocum D, Sloan V, et al. Standardizing 
assessment and reporting of adverse effects in rheumatology clinical trials II: the Rheumatology 
Common Toxicity Criteria v.2.0. J Rheumatol. 2007;34:1401-14. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 114 of 142 
18 
APPENDICES 
18.1 
Classification Criteria for Psoriatic Arthritis  
Inflammatory articular disease (joint, spine, or entheseal) AND at least 3 points of the following 
5 categories: 
Table 18-1: CASPAR Criteria 
Category 
Definition 
Points 
1) Evidence of psoriasis:  
(Score for 1 of the following a) 
 
 
Current psoriasis 
Psoriatic skin or scalp disease present today as 
judged by a dermatologist or rheumatologist 
2 points 
Personal history of psoriasis 
A history of psoriasis that may be obtained from the 
subject, family physician, dermatologist, 
rheumatologist, or other qualified health care 
provider 
1 point 
Family history of psoriasis 
A history of psoriasis in a first- or second-degree 
relative according to subject report 
1 point 
2) Psoriatic nail dystrophy 
Typical psoriatic nail dystrophy, including 
onycholysis, pitting, and hyperkeratosis, observed on 
current physical examination 
1 point 
3) A negative test for rheumatoid 
factor 
By any method except latex, but preferably by 
enzyme-linked immunosorbent assay (ELISA) or 
nephelometry, according to the local laboratory 
reference range 
1 point 
4) Dactylitis:  
(Score for 1 of the following) 
 
 
Current dactylitis 
Swelling of an entire digit 
1 point 
History of dactylitis 
A history of dactylitis recorded by a rheumatologist 
1 point 
5) Radiologic evidence of 
juxta-articular new bone 
formation 
Ill-defined ossification near joint margins (but 
excluding osteophyte formation) on plain radiographs 
of the hand or foot 
1 point 
CASPAR=Classification Criteria for Psoriatic Arthritis  
a “Score for 1 of the following” means that only 1 of the 3 criteria is applicable (either current psoriasis [scores 2 
points], personal history [scores 1 point], or family history [scores 1 point]). 
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 115 of 142 
18.2 
Protocol Amendment 1 
The main purpose of this protocol amendment was to update the completed and ongoing studies 
information, clarify study procedures, add re-screening rules, update the description of the IMP, 
change the statistical hierarchy, and update the statistical section. 
Modifications and changes 
Global changes: 
The following changes were made throughout the protocol and are not included in specific 
changes table that follows:  
• The company name was changed from UCB Biopharma SPRL to UCB Biopharma SRL 
• The term “legal representative” was deleted from protocol, as it is not applicable to PA0011 
• Minor spelling, editorial, and formatting changes were made throughout the document  
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 116 of 142 
Specific changes: 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Change 1: Administrative section 
Study contact details 
 
UCB PHARMA Ltd 
208 Bath Road 
Slough SL1 3WE 
 
 
UCB BIOSCIENCES GmbH 
Alfred-Nobel-Str. 10 
40789 Monheim 
GERMANY 
 
The Sponsor Study Physician has 
changed. 
 
UCB BIOSCIENCES Inc. 
8010 Arco Corporate Drive 
Raleigh, NC 27617 
UNITED STATES 
 
 
UCB BIOSCIENCES GmbH 
Alfred-Nobel-Str. 10 
40789 Monheim 
GERMANY 
 
The Clinical Project Manager has 
changed.  
 
UCB PHARMA Ltd 
Alfred-Nobel-Strasse 10 
40789 Monheim am Rhein 
GERMANY 
 
 
UCB BIOSCIENCES Inc. 
8010 Arco Corporate Drive 
Raleigh, NC 27617 
UNITED STATES 
 
The Clinical Trial Biostatistician 
has changed. 
Change 2: Abbreviations added 
List of abbreviations 
Abbreviations and definitions are added for the following: HS, OC, and UC 
Abbreviations used in text. 
Change 3: Updated text in bimekizumab section 
Section 2.2 
Furthermore, a proof-of-concept study 
with bimekizumab in subjects with 
moderate-to-severe PsA demonstrated 
a strong efficacy signal that warrants 
further exploration of bimekizumab in 
Furthermore, a proof-of-concept study 
(PA0007) with bimekizumab in 
subjects with moderate to severe PsA 
demonstrated a strong efficacy signal 
that warrants further exploration of 
Added PA0007 study number and 
updated PA0008 sentence since the 
study is now completed. Also, 
corrected error in statement about 
PA0011. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 117 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
this indication. A Phase 2b, dose-
ranging study (PA0008) is an ongoing 
study that was designed to investigate 
the efficacy and safety of various 
bimekizumab dose regimens in 
subjects with active PsA. The current 
Phase 3, randomized, double-blind, 
placebo-controlled, and active-
controlled confirmatory study 
(PA0011) is designed to investigate the 
efficacy and safety of bimekizumab in 
subjects with active PsA. 
bimekizumab in this indication. A 
Phase 2b, dose-ranging study 
(PA0008) is an ongoing study that was 
designed to investigate the efficacy 
and safety of various bimekizumab 
dose regimens in subjects with active 
PsA. The current Phase 3, randomized, 
double-blind, placebo-controlled, and 
active controlled confirmatory study 
(PA0011) is designed to investigate the 
efficacy and safety of bimekizumab in 
subjects with active PsA. 
Change 4: Updated text in nonclinical studies section 
Section 2.2.1 
Preliminary results from the 
embryofetal and postnatal study 
conducted in the Cynomolgus monkey 
indicate no effects of bimekizumab on 
the gestation, gestation duration, or the 
parturition of pregnant females. 
Preliminary rResults from the 
embryofetal and postnatal study 
conducted in the Cynomolgus monkey 
indicate no effects of bimekizumab on 
the gestation, gestation duration, or the 
parturition of pregnant females. 
This nonclinical study is now 
completed. 
Change 5: Updated text in clinical studies section 
Section 2.2.2.1 
This section was updated to reflect the studies that have completed as of 02 Dec 
2019. Detailed study descriptions for non-PsA studies were deleted and cross-
reference to the bimekizumab IB was added for detail of these studies. Psoriatic 
arthritis PA0007 summary remains, and a summary of the recently completed 
PA0008 was added. 
More studies have completed, and 
additional studies have started since 
the original protocol was written. 
Section 2.2.2.2 
This section was updated to reflect studies that are ongoing as of 02 Dec 2019. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 118 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Change 6: Updated secondary efficacy variables 
Section 4.2.1 
The secondary efficacy variables for 
this study are as follows: 
• 
PASI90 response at Week 4 and 
Week 16 in the subgroup of 
subjects with PSO involving at 
least 3% BSA at Baseline 
• 
Change from Baseline in Health 
Assessment Questionnaire—
Disability Index (HAQ-DI) at 
Week 16 
• 
Change from Baseline in the 
Short-Form 36-item Health Survey 
(SF-36) Physical Component 
Summary (PCS) at Week 16 
• 
etc  
The secondary efficacy variables for 
this study are as follows: 
• 
Change from Baseline in Health 
Assessment Questionnaire—
Disability Index (HAQ-DI) at 
Week 16 
• 
PASI90 response at Week 4 and 
Week 16 in the subgroup of 
subjects with PSO involving at 
least 3% BSA at Baseline 
• 
Change from Baseline in Health 
Assessment Questionnaire—
Disability Index (HAQ-DI) at 
Week 16 
• 
Change from Baseline in the 
Short-Form 36-item Health Survey 
(SF-36) Physical Component 
Summary (PCS) score at Week 16 
• 
etc 
The HAQ-DI variable was 
promoted in the testing hierarchy. 
Section 14.3.1 
Figure 14-1 
In Figure 14-1 Sequential testing procedure of primary/secondary efficacy 
endpoints (fixed sequence testing procedure), the variable of Change from 
Baseline HAQ-DI at Week 16 superior to placebo was moved from the 3rd 
position in the sequential testing hierarchy to the 2nd position (after the primary 
variable). 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 119 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Change 7: Made minor update to secondary safety variables 
Section 4.2.2 
Secondary safety variables to be 
assessed are as follows: 
• 
Incidence of treatment-emergent 
adverse events (TEAEs) 
• 
Incidence of SAEs 
• 
Adverse events leading to 
withdrawal from IMP 
 
Secondary safety variables to be 
assessed are as follows: 
• 
Incidence of treatment-emergent 
adverse events (TEAEs) 
• 
Incidence of treatment-emergent 
SAEs 
• 
Treatment-emergent adverse 
events leading to withdrawal from 
IMP 
Clarified variables. 
Change 8: Updated PsAID-12 variables 
Section 4.3.1  
• Change from Baseline PsAID-12 
• 
Change from Baseline in 
PsAID-12 total score 
• 
Change from Baseline in the 
individual domain scores of 
PsAID-12 
• 
Proportion of subjects achieving 
PsAID-12 total score ≤4 
• Change from Baseline in PsAID-
12 total score ≥3 (PsAID-12 
responders) 
The variables were updated for 
consistency with the SAP. 
Change 9: Updated Other efficacy variables 
Section 4.3.1 
• 
Change from Baseline in the 
Psoriatic Arthritis Quality of Life 
(PsAQoL) 
• 
Change from Baseline in the SF-
36 PCS and Mental Component 
Summary (MCS), as well as the 8 
domain scores (Physical 
Functioning, Role Physical, Bodily 
Pain, General Health, Vitality, 
• 
Change from Baseline in the 
Psoriatic Arthritis Quality of Life 
(PsAQoL) global score 
• 
Change from Baseline in the 
SF-36 PCS and SF-36 Mental 
Component Summary (MCS) 
scores, as well as the 8 domain 
scores (Physical Functioning, Role 
Physical, Bodily Pain, General 
Minor editorial changes and 
variables were updated for 
consistency with the SAP. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 120 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Social Functioning, Role 
Emotional, and Mental Health) 
• 
Change from Baseline in 
Functional Assessment of Chronic 
Illness Therapy—Fatigue 
(FACIT-F) 
• 
Change from Baseline in Work 
Productivity and Activity 
Impairment Questionnaire–
Specific Health Problem (WPAI-
SHP) v2.0 adapted to PsA scores 
• 
Responses to the EuroQol-5D-3-
Level (EQ-5D-3L) dimensions 
• 
Change from Baseline in the EQ-
5D-3L utility score 
• 
Change from Baseline in EQ-5D-
3L Visual Analog Scale (VAS) 
scores 
Health, Vitality, Social 
Functioning, Role Emotional, and 
Mental Health) 
• 
Change from Baseline in 
Functional Assessment of Chronic 
Illness Therapy—Fatigue 
(FACIT-F) score 
• 
Change from Baseline in Work 
Productivity and Activity 
Impairment Questionnaire–
Specific Health Problem (WPAI-
SHP) v2.0 adapted to PsA scores 
• 
Responses to the EuroQol-5D-3-
Level (EQ-5D-3L) dimensions 
• 
Change from Baseline in the EQ-
5D-3L utility score 
• 
Change from Baseline in EQ-5D-
3L Visual Analog Scale (VAS) 
scores 
• 
Change from Baseline in 
Physician’s Global Assessment 
of Arthritis (PhGA-Arthritis) 
• 
Change from Baseline in 
Patient’s Global Assessment of 
Arthritis (PGA-Arthritis) 
Change 10: Moved PHQ-9 variable 
Section 4.3.1 
Section 4.3.2 
• Change from Baseline in Patient 
Health Questionnaire-9 (PHQ-9)   
Was in Section 4.3.1 Other efficacy 
variables 
• Change from Baseline in Patient 
Health Questionnaire-9 (PHQ-9)  
Is now in Section 4.3.2 Other safety 
variables 
PHQ-9 is a safety variable. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 121 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Change 11: Made minor update to study design section 
Section 5.1 
Subjects completing Week 16 are 
eligible for enrollment in an OLE 
study to continue to receive 
bimekizumab. 
Subjects completing Week 16 and 
meeting eligibility criteria are 
eligible for enrollment in an OLE 
study to continue to receive 
bimekizumab. 
Clarification of procedure. 
Change 12: Added text regarding rescreening and retesting requirements 
Section 5.2 
The following new section was added in Section 5.2: 
5.2.1  Within-study rescreening/retesting requirements  
Clarified rules for when rescreening 
and/or retesting is allowed. 
Change 13: Made minor updates to Schedule of study assessments 
Table 5-1 
a Visit windows of ±3 days from the first 
dose at all visits through Week 16. The 
time between IMP doses should be ≥21 
days and ≤35 days during the Double-
Blind Treatment Period. The Safety 
Follow-Up Visit window is -3 and +7 
days from the final dose. 
a Visit windows of ±3 days from the first 
dose at all visits through Week 16. The 
time between IMP doses should be ≥21 
days and ≤35 days during the Double-
Blind Treatment Period. The Safety 
Follow-UpFor the SFU Visit window is, 
the visit should occur no more than 3 
days prior to the scheduled -3visit date 
and +within 7 days from the final 
dose.after the scheduled visit date (-3 
days/+7 days). 
Clarification of the SFU Visit 
timing. 
o 
Circumference measured in 
millimeters. 
o Circumference measured in 
millimeters. The LDI assessment of 
dactylitis will be obtained for all 
subjects at all visits after the 
Screening Visit. 
Clarification of the LDI assessment 
timing. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 122 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Change 14: Made minor updates to Inclusion criteria  
Section 6.1 
1. An Institutional Review Board 
(IRB)/Independent Ethics 
Committee (IEC) approved written 
Informed Consent form is signed 
and dated by the subject or legal 
representative. 
2. Subject/legal representative is 
considered reliable and capable of 
adhering to the protocol (eg, able to 
understand and complete diaries), 
visit schedule, or medication intake 
according to the judgment of the 
Investigator. 
1a. An Institutional Review Board 
(IRB)/Independent Ethics 
Committee (IEC) approved written 
Informed Consent form is signed 
and dated by the subject or legal 
representative. 
2a. Subject/legal representative is 
considered reliable and capable of 
adhering to the protocol (eg, able to 
understand and complete diaries), 
visit schedule, or medication intake 
according to the judgment of the 
Investigator. 
Numbering of these inclusion 
criteria needed to change due to 
change in wording.  
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 123 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Change 15: Made updates to potential drug-induced livery injury (PDILI) IMP discontinuation criteria 
Section 6.3.1 
Section 12.2.1.2 
The PDILI criteria below require 
immediate and permanent 
discontinuation of IMP:  
• 
Subjects with either of the 
following: 
− 
ALT or AST ≥8xULN  
− 
ALT or AST ≥3xULN and 
coexisting total bilirubin 
≥2xULN  
The PDILI criterion below requires 
immediate discontinuation of IMP for: 
• 
Subjects with ALT or AST 
≥3xULN who exhibit temporally 
associated symptoms of hepatitis 
or hypersensitivity. Hepatitis 
symptoms include fatigue, nausea, 
vomiting, right upper quadrant 
pain or tenderness. 
Hypersensitivity symptoms 
include fever (without clear 
alternative cause), rash, or 
eosinophilia (ie, >5%). 
The PDILI criteria below require 
immediate and permanent 
discontinuation of IMP:  
• 
Subjects with either of the 
following: 
− 
ALT or AST ≥8xULN  
− 
ALT or AST ≥3xULN and 
coexisting total bilirubin 
≥2xULN  
The PDILI criterion below requires 
immediate discontinuation of IMP for: 
• 
Subjects with ALT or AST 
≥3xULN who exhibit temporally 
associated symptoms of hepatitis 
or hypersensitivity. Hepatitis 
symptoms include fatigue, nausea, 
vomiting, right upper quadrant 
pain or tenderness. 
Hypersensitivity symptoms 
include fever (without clear 
alternative cause), rash, or 
eosinophilia (ie, >5%). 
Requirements for IMP 
discontinuation were clarified, and 
the requirement for permanent 
discontinuation of IMP was 
removed. 
Section 12.2.1, 
Table 12-3 
The table was simplified and criteria for IMP discontinuation was updated in line 
with changes made to Section 6.3.1. 
In addition, a table footnote with cross-reference to Section 12.2.1.2 was added 
as footnote d and the previous footnote d became footnote e. 
Section 12.2.1.2.1 
Subjects who are immediately 
discontinued from IMP due to having 
met certain criteria for PDILI (as 
described in Section 6.3.1 and Table 
12‒3), but for whom an alternative 
Subjects who are immediately 
discontinued from IMP due to having 
met certain criteria for PDILI (as 
described in Section 6.3.1 and Table 
12‒3), but for whom an alternative 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 124 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
diagnosis is confirmed, ie, drug-
induced liver injury is excluded, can 
rarely restart IMP. Rechallenge with 
IMP can occur only if ALL of the 
following requirements are met: 
diagnosis is confirmed, ie, drug-
induced liver injury is excluded, can 
rarely restart IMP. Rechallenge with 
IMP can occur only if ALL of the 
following requirements are met at the 
time of the rechallenge: 
Change 16: Updated description of IMP 
Section 7.1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Updated to be consistent with other 
studies in bimekizumab clinical 
development program. 
Change 17: Updated prohibited concomitant treatments section  
Section 7.8.2, 
Table 7-1 
Exclusion/washout for oral 
corticosteroids: 
Any change in dose/dose regimen in 
the 28 days prior to the Baseline Visit. 
Exclusion/washout for oral 
corticosteroids: 
Any change in dose/dose regimen in 
the 28 14 days prior to the Baseline 
Visit. 
Updated washout timing 
requirements. 
Exclusion/washout for methotrexate: 
Use within 8 weeks prior to the 
Baseline Visit unless Inclusion 
Criterion #11 is met.   
Exclusion/washout for methotrexate: 
Use within 8Initiation less than 
12 weeks prior to the Baseline Visit 
unless Inclusion Criterion #11 is met.   
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 125 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Change 18: Updated text in IGA section  
Section 9.8.3 
Added the following text under Table 9-3: 
The IGA responder is defined as a subject with a clear (0) or almost clear 
(1) assessment with at least a 2-category improvement from Baseline, 
meaning that this parameter will be evaluable only for subjects with 
psoriatic skin lesions (IGA score ≥2) at Baseline. 
In this study, only subjects with BSA ≥ 3% at Baseline will have IGA 
assessed at post-Baseline visits. 
The section needed a definition of 
IGA responder added to assessment 
description. 
Change 19: Updated DAPSA formula  
Section 9.10 
SJC (range 0 to 66) + TJC (range 0 to 
68) + PGA-Arthritis and patient’s pain 
assessment (VAS range 0 to 10; 
0=best, 10=worst) + hs-CRP 
DAPSA=SJC (range 0 to 66) + TJC 
(range 0 to 68) + PGA-Arthritis and 
patient’s pain assessment (VAS range 
0 to 10cm; 0=best, 10=worst) + 
PtAAP (VAS range 0 to 10cm) + hs-
CRP 
Corrected formula. 
Change 20: Updated DAS28(CRP) formula  
Section 9.11 
DAS28(CRP)=0.56 √TJC+0.28 
√SJC+0.014 PGA-Arthritis+0.36 
ln(hs-CRP+1)+0.96 
DAS28(CRP)=0.56 √TJC+0.28 
√SJC+0.014 PGA-Arthritis+0.36 
ln(hs-CRP+1)+0.96 
Corrected formula. 
Change 21: Moved PHQ-9 assessment section from efficacy assessments to safety assessments  
Old Section 9.22 
moved to  
New Section 12.3.5 
12.3.5 Assessment and management of 
TB and TB risk factors 
12.3.6 Pregnancy testing 
12.3.7 Assessment of suicidal ideation 
and behavior  
12.3.5 Patient Health 
Questionnaire-9 (PHQ-9) 
12.3.6 Assessment and management of 
TB and TB risk factors 
12.3.7 Pregnancy testing 
12.3.8 Assessment of suicidal ideation 
and behavior 
The PHQ-9 is a safety variable and 
was moved to Other safety 
variables from Other efficacy 
variables in the current amendment. 
The assessment description section 
was moved to align with the 
variable change. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 126 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Change 22: Updated text in pregnancy section  
Section 12.1.4 
If the Investigator is notified that a 
subject has become pregnant after the 
first intake of any IMP, the 
Investigator must immediately notify 
UCB’s PS department by entering all 
pregnancy information into the eCRF. 
An automatic notification will be sent 
to UCB PS. The subject should be 
withdrawn from the study as soon as 
pregnancy is known (by positive 
pregnancy test), and the following 
should be completed: 
• 
The subject should return for the 
ET Visit. 
• 
The subject should immediately 
stop the intake of the IMP. 
• 
A Safety Follow-Up Visit should 
be scheduled 20 weeks after the 
final dose of IMP. 
The Investigator must inform the 
subject of information currently known 
about potential risks and about 
available treatment alternatives. 
 
If the Investigator is notified that a 
subject has become pregnant after the 
first intake of any IMP, the 
Investigator must immediately (within 
24 hours) notify UCB’s PS 
department by entering all pregnancy 
information into the eCRF. An 
automatic notification will be sent to 
UCB PS. The subject should be 
permanently withdrawn from the 
study IMP as soon as pregnancy is 
known (by positive pregnancy test), 
and the following should be 
completed: 
• 
The subject should return for the 
ET Visit. 
• 
The subject should immediately 
stop the intake of the IMP. 
• 
The subject should return for an 
early ad-hoc study visit. 
• 
A Safety Follow-Up Visit should 
be scheduled 20 weeks after the 
final dose of IMP. 
The Investigator should discuss with 
the subject the possibility to 
continue the study by attending the 
Clarified pregnancy instructions. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 127 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
scheduled visits for assessments 
without IMP administration. The 
tests or assessments, which are 
considered contraindicated during 
the pregnancy should not be 
performed. The early ad-hoc study 
visit will be considered as the ET 
visit if the subject does not wish to 
pursue the study investigations. 
The Investigator must inform the 
subject of information currently known 
about potential risks and about 
available treatment alternatives. 
Section 12.1.4 
Last paragraph regarding the “option to enroll in a separate observational 
pregnancy follow-up study” was deleted. 
There is no pregnancy registrational 
study. 
Change 23: Updated text in analysis of the primary efficacy variable section 
Section 14.3.1.1 
Provided additional detail regarding the statistical approach to be used for 
analyzing ACR response. 
Updated protocol to be consistent 
with SAP. 
Section 14.3.1.1.1 
Added clarification regarding sensitivity analyses to be used. 
Change 24: Updated text in analysis of the secondary efficacy variables section 
Section 14.3.1.2 
Provided additional detail regarding the statistical approach to be used for 
analyzing secondary efficacy variables. 
Updated protocol to be consistent 
with SAP. 
Change 25: Updated text in analysis of the other efficacy variables section 
Section 14.3.2 
Provided additional detail regarding the statistical approach to be used for 
analyzing the other efficacy variables. 
Updated protocol to be consistent 
with SAP. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 128 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Change 26: Updated subgroup analyses section 
Section 14.3.3 
Added the following subgroup: 
• 
Concomitantly receiving MTX versus no concomitant MTX 
Added subgroup consistent with 
SAP. 
Change 27: Updated text in handling of dropouts or missing data section 
Section 14.7 
Added some detail regarding the statistical approach to be used for missing data 
for composite endpoints and the supportive analyses based on OC and NRI. 
Updated protocol to be consistent 
with SAP. 
Change 28: Updated text in data monitoring section 
Section 14.8.1 
Added the following statement: 
Other adjudication committees may be added as necessary. 
Allowing the possibility for 
additional committees to be utilized 
during study. 
 
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 129 of 142 
18.3 
Protocol Amendment 2 
The main purpose of this protocol amendment was to modify the secondary variables and fixed 
sequence testing procedure, update the statistical section, and make other procedural 
clarifications. 
Modifications and changes 
Global changes: 
Throughout the protocol, FACIT-F has been corrected to FACIT-Fatigue subscale, as it is the 
fatigue subscale that is being assessed in this study. In addition, minor spelling, editorial, and 
formatting changes were made throughout the protocol. These global changes are not included in 
specific changes table that follows.  
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 130 of 142 
 
Specific changes: 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Change 1: Administrative section 
Study contact details 
 
UCB BIOSCIENCES GmbH 
Alfred-Nobel-Str. 10 
40789 Monheim 
GERMANY 
 
 
 
UCB Celltech Ltd 
208 Bath Road 
Slough SL1 3WE 
 
The Sponsor Study Physician has 
changed. 
 
UCB BIOSCIENCES GmbH 
Alfred-Nobel-Str. 10 
40789 Monheim 
GERMANY 
 
 
UCB Biopharma SRL 
Chemin du Foriest 
Brain-l’Alleud B-1420 
BELGIUM 
 
The Sponsor Clinical Project 
Manager has changed. 
 
UCB BIOSCIENCES Inc.  
8010 Arco Corporate Drive 
Raleigh, NC 27617 
UNITED STATES 
 
 
UCB BIOSCIENCES Inc.  
4000 Paramount Pkwy, 
 
Morrisville, NC 27560 
UNITED STATES 
 
The address of the North Carolina, 
US office has changed. 
Change 2: Abbreviations added 
List of abbreviations 
Abbreviations and definitions added for the following: COVID-19, DNA, 
mRNA, LN, PsARC, PASDAS 
Abbreviations used in text. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 131 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Change 3: Updated text in clinical studies section 
Section 2.2.2.1 
The list of completed studies was updated consistent with the current 
bimekizumab IB.  
More studies have completed, and 
additional studies have started, 
since the last protocol amendment. 
Section 2.2.2.2 
The list of ongoing studies was updated consistent with the current bimekizumab 
IB. 
Change 4: Added 6 new Other efficacy variables 
Section 4.3.1 
Added the following variables:  
• 
Composite endpoint composed of ACR50 and PASI100 response in 
subjects with PSO involving at least 3% BSA at Baseline 
• 
Proportion of Psoriatic Arthritis Response Criteria (PsARC) responders 
• 
Psoriatic Arthritis Disease Activity Score (PASDAS) categories 
• 
Change from Baseline in the PASDAS  
• 
Proportion of subjects with a decrease of HAQ-DI from Baseline of at 
least 0.35 in those subjects with HAQ-DI >0.35 at Baseline 
• 
Proportion of FACIT-Fatigue subscale responders (subjects with a 
minimum clinically important difference for FACIT-Fatigue subscale 
score, defined as an increase of ≥4) in subjects with FACIT-Fatigue 
subscale score ≤48 at Baseline 
Updated to be consistent with 
variables added to the SAP 
Change 5: Updated wording in other efficacy variables 
Section 4.3.1 
• 
Disease Activity Index for 
Psoriatic Arthritis (DAPSA) score 
• 
Disease Activity Index for Psoriatic 
Arthritis (DAPSA) score categories 
Corrected wording  
• 
Change from Baseline in PsAID-
12 total score ≥3 (PsAID-12 
responders) 
• 
Proportion of PsAID-12 
responders (decrease Change from 
Baseline in PsAID-12 total score 
≥3) (PsAID-12 responders) in 
subjects with PsAID-12 total 
score >3 at Baseline 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 132 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
• 
Change from Baseline in the 
Psoriatic Arthritis Quality of Life 
(PsAQoL) global score 
• 
Change from Baseline in the 
Psoriatic Arthritis Quality of Life 
(PsAQoL) global total score 
• 
Change from Baseline in 
Functional Assessment of 
Chronic Illness Therapy—Fatigue 
(FACIT-F) 
• 
Change from Baseline in 
Functional Assessment of Chronic 
Illness Therapy—Fatigue 
(FACIT-F) subscale score 
Change 6: Updated the planned number of sites 
Section 5.6 
Approximately 390 subjects will be 
randomly assigned in a 2:1 ratio to the 
following treatment groups: 
bimekizumab 160mg sc Q4W (260 
subjects) and placebo (130 subjects). 
The planned number of study sites is 
approximately 89. 
Approximately 390 subjects will be 
randomly assigned in a 2:1 ratio to the 
following treatment groups: 
bimekizumab 160mg sc Q4W (260 
subjects) and placebo (130 subjects). 
The planned number of study sites is 
approximately 89120. 
The planned number of sites was 
adjusted. 
Change 7: Added a withdrawal criterion 
Section 6.3 
Added the following to the list of withdrawal criteria: 
13. Any subject who develops a clinically important infection or recurrent 
infections not responsive to standard therapy during the study must 
discontinue IMP until resolution of the infection. The Investigator should 
use clinical judgement in deciding whether the subject should restart IMP 
and contact the Medical Monitor and UCB study physician to confirm the 
subject’s suitability for continued participation in the study. 
In line with the exclusion 
criterion 11 regarding infections, a 
specific infection-related 
withdrawal criterion was added to 
clarify that patients with serious or 
recurrent infections not responding 
to standard therapies are not 
exposed to immunomodulatory 
therapies until their infection is 
resolved. This is in line with most 
biologic therapies, including other 
anti-IL17s. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 133 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Change 8: Updated the permitted concomitant treatments section 
Section 7.8.1 
Added the following paragraph to the section:  
Subjects are allowed to use any other medications, including biologics, after at 
least 28 days of last dose of the IMP. This is applicable for subjects who 
discontinue from IMP or the study early, including those permanently withdrawn 
from IMP, or subjects who have completed the study treatment without entering 
the extension study and are in the SFU period.  
Clarification of permitted 
concomitant medications. 
Change 9: Updated the vaccines section 
Section 7.8.3 
Added the following paragraph to the section: 
Administration of inactivated vaccines is allowed during the study at the 
discretion of the Investigator. This includes administration of non-live 
coronavirus disease 2019 (COVID-19) vaccines authorized at the time of 
issuance of this protocol version (eg, messenger ribonucleic acid [mRNA], 
deoxyribonucleic acid [DNA] viral vector types of vaccines). Considering the 
known mechanism of action and results from a human vaccination response 
study, bimekizumab is not expected to affect the safety and/or efficacy of 
COVID-19 vaccines. 
Clarification that administration of 
COVID-19 vaccines are allowed at 
the discretion of the Investigator. 
Change 10: Updated FACIT-Fatigue assessment section 
Section 9.18 
The FACIT–F scale (Cella et al, 
2005) will be used to assess fatigue in 
PsA patients. The FACIT-F has been 
validated in the general population, in 
patients with RA, and in patients with 
PsA. The minimum clinically 
important difference for FACIT-F in 
patients with RA was determined to 
be a 3 to 4-point change; this 
minimum clinically important 
difference will be used in evaluating 
The FACIT–F scale (Cella et al, 2005) 
will be used to assess fatigue in PsA 
patients. The FACIT-Fatigue is a 
40-item measure that assesses 
self-reported fatigue and its impact 
upon daily activities and function 
over the past 7 days (FACIT.org). 
The scale consists of 5 subscales 
(physical well-being, social/family 
well-being, emotional well-being, 
functional well-being, and fatigue). 
The fatigue subscale is the only one 
Added a reference for FACIT-
Fatigue subscale use in PsA. 
Wording changes implemented for 
consistency with the user manuals 
and to reflect precise description of 
the patient-reported outcomes 
(PRO) tool and scoring (change in 
terminology but no change in the 
method). 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 134 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
clinically meaningful changes in 
fatigue for patients with PsA. 
used in this study. It is composed of 
13 items, all scored from 0 (Not at all) 
to 4 (Very much). The 
FACIT-Fatigue subscale score ranges 
from 0 to 52 with 0 being the worst 
possible score and 52 being the best 
possible score. To obtain a score from 
0 to 52, all negatively worded 
questions have to be recoded, so that 
responses range from worst (0) to the 
best (4) outcome. 
The FACIT-Fatigue subscale has been 
validated in the general population, in 
patients with RA, and in patients with 
PsA. The minimum clinically important 
difference for FACIT-Fatigue subscale 
in patients with RAPsA was determined 
to be a 3   to 4-point change (Cella et 
al, 2019); this minimum clinically 
important difference will be used in 
evaluating clinically meaningful 
changes in fatigue for patients with 
PsA. 
Change 11: Updated SF-36 assessment section 
Section 9.19 
In addition to domain scores, the PCS 
and MCS scores are calculated from 
the 8 domains (excluding the Health 
Transition item). Component scores 
appreciate the impact of each domain 
on physical and mental health status 
(Maruish, 2011). Each of the 8 
domain scores and the component 
summary scores range from 0 to 100, 
In addition to domain scores, the PCS 
and MCS scores are calculated from the 
8 domains (excluding the Health 
Transition item). Component scores 
appreciate reflect the impact of each 
domain on physical and mental health 
status (Maruish, 2011). Each of the 8 
domain scores and the component 
summary scores range from 0 to 100, 
Wording changes implemented for 
consistency with the user manuals 
and to reflect precise description of 
the PRO tools and scoring (change 
in terminology but no change in the 
method). 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 135 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
with a higher score indicating a better 
health status. The 2 component 
summary scores are standardized with 
a mean of 50 and a standard deviation 
(SD) of 10 in the general US 
population. 
with a higher score indicating a better 
health status. The norm-based T-
scores for the 2 SF-36 component 
summary scores (PCS and MCS) and 
the 8 domains are standardized with a 
mean of 50 and a standard deviation 
(SD) of 10 in the general US population 
(Maruish, 2011). An individual 
respondent’s score that falls outside 
the T-score range of 45 to 55 should 
be considered outside the average 
range for the US general population. 
When considering group-level data, a 
score below 47 should be considered 
indicative of impaired functioning 
within that health domain or 
dimension. Similar to individual 
respondent data, group mean scores 
of 47 or greater should be considered 
average or above average as 
compared to the general US 
population. Higher scores indicate a 
better health status. 
Change 12: Added 2 new sections to describe the PsARC and PASDAS efficacy assessments added in new Other efficacy variables 
New Section 9.22 
Section 9.22 Psoriatic Arthritis Response Criteria (PsARC) added to describe the 
PsARC efficacy assessment 
The PsARC was added in a new 
Other efficacy variable 
New Section 9.23 
Section 9.23 Psoriatic Arthritis Disease Activity Score (PASDAS) added to 
describe the PASDAS efficacy assessment 
The PASDAS was added in 2 new 
Other efficacy variables. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 136 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Change 13: Updated Other safety topics of interest section 
Section 12.1.1.4 
Prespecified safety topics of interest 
for the study are: infections (serious, 
opportunistic, fungal and TB), 
neutropenia, hypersensitivity, suicidal 
ideation and behavior, depression, 
major cardiovascular events, liver 
function test changes/enzyme 
elevations, malignancies, and 
inflammatory bowel diseases (with 
gastroenterology referral, as 
appropriate). 
Prespecified safety topics of interest for 
the study are: infections (serious, 
opportunistic, fungal and TB), 
neutropenia, hypersensitivity, suicidal 
ideation and behavior, depression, 
major cardiovascular events, liver 
function test changes/enzyme 
elevations, malignancies, and 
inflammatory bowel diseases (with 
gastroenterology referral, as 
appropriate). 
With progressive development of 
bimekizumab and based on the 
ongoing review of emerging safety 
data, depression has been removed 
as a safety topic of interest. 
Nevertheless, depression will 
continue to be monitored as a safety 
parameter by the PHQ-9 and will 
be captured via routine AE 
reporting during the study. This 
update is considered a procedural 
change. 
Change 14: Updated Evaluation of PDILI section 
Section 12.2.1 
The PDILI IMP discontinuation 
criteria for this study are provided in 
Section 6.3.1, with the accompanying 
required follow-up investigation and 
monitoring detailed below. All PDILI 
events must be reported as AEs and 
reported to the study site and Sponsor 
within 24 hours of learning of their 
occurrence. Any PDILI event that 
meets the criterion for potential Hy’s 
Law must be reported as an AE of 
special interest (see Section 12.1.1.3), 
and, if applicable, also reported as an 
SAE (see Section 12.1.1.2). 
The PDILI IMP discontinuation criteria 
for this study are provided in Section 
6.3.1, with the accompanying required 
follow-up investigation and monitoring 
detailed below. All PDILI events must 
be reported as AEs and reported to the 
study site PDILI events meeting SAE 
criteria should be reported to the 
Sponsor within 24 hours of learning of 
their occurrence. Any PDILI event that 
meets the criterion for potential Hy’s 
Law must be reported within 24 hours 
of learning of their occurrence as an 
AE of special interest (see 
Section 12.1.1.3), and, if applicable, 
also reported as an SAE (see 
Section 12.1.1.2). 
Clarified PDILI event reporting 
procedure. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 137 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Section 12.2.1.2 
The immediate action is dependent on 
the laboratory values and symptoms 
of hepatitis or hypersensitivity and 
ranges from continuation of IMP 
(followed by immediate investigation) 
to immediate discontinuation (see 
Section 6.3.1 and Table 12‒3 for 
details). 
The immediate action is dependent on 
the laboratory values and symptoms of 
hepatitis or hypersensitivity and ranges 
from continuation of IMP (followed by 
immediate investigation) to immediate 
and permanent discontinuation (see 
Section 6.3.1 and Table 12‒3 for 
details). 
Clarify the range of potential 
actions. 
Change 15: Updated the analysis set definition section 
Section 14.1 
• 
The Per-Protocol Set (PPS) will 
consist of all subjects in the RS 
who had no important protocol 
deviations affecting the primary 
efficacy variable. Important 
protocol deviations will be 
predefined and subjects with 
important protocol deviations will 
be evaluated during ongoing data 
cleaning meetings prior to 
unblinding of the data. 
• 
The Pharmacokinetic Per-
Protocol Set (PK-PPS) consists of 
all randomized subjects who 
received at least one dose of the 
IMP and provided at least one 
quantifiable plasma concentration 
post-dose without important 
protocol deviations that would 
affect the concentration.  
 
• 
The Per-Protocol Set (PPS) will 
consist of all subjects in the RS 
who had no important protocol 
deviations affecting the primary 
efficacy variable. Important 
protocol deviations will be 
predefined and subjects with 
important protocol deviations will 
be evaluated during ongoing data 
cleaning meetings prior to 
unblinding of the data. Exclusions 
from the FAS will be considered 
important protocol deviations 
that also result in exclusion from 
the PPS. 
• 
The Pharmacokinetic Per-Protocol 
Set (PK-PPS) consists of all 
randomized subjects who received 
at least one dose of the IMP and 
provided at least one quantifiable 
plasma concentration post-dose 
without important protocol 
deviations that would affect the 
Clarified PPS and PK-PPS 
definitions. 
Added COVID-19-free analysis set 
to determine if COVID-19 has an 
impact on analyses. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 138 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
concentration. Exclusions from the 
FAS will be considered important 
protocol deviations that also 
result in exclusion from the PK-
PPS. 
• 
The COVID-19-free Set will 
consist of all subjects in the RS 
who had no COVID-19 impact up 
to the primary efficacy endpoint. 
This will be defined as subjects 
not having a COVID-19 related 
important protocol deviation, nor 
having an impact based on the 
COVID-19 eCRF, nor having an 
AE related to COVID-19, nor 
discontinuing due to COVID-19 
up to the time of the primary 
endpoint. 
Change 16: Updated text in analysis of the primary efficacy variables section 
Section 14.3.1.1 
Updated text regarding the statistical approach to be used for analyzing primary 
efficacy variable. 
Updated statistical methods based 
on feedback from the FDA. 
Change 17: Updated title and text in former Sensitivity analyses section 
Section 14.3.1.1.1 
Updated title of this section from Sensitivity analyses to SensitivitySupportive 
analyses. Also, updated text regarding the statistical approach to be used for the 
supportive analyses. 
Updated statistical methods based 
on feedback from the FDA. 
Change 18: Updated text in analysis of the secondary efficacy variables section 
Section 14.3.1.2 
Updated text regarding the statistical approach to be used for analyzing 
secondary efficacy variables. 
Updated statistical methods based 
on feedback from the FDA. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 139 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
Change 19: Updated text in analysis of the other efficacy variables section 
Section 14.3.2 
Updated text regarding the statistical approach to be used for analyzing the other 
efficacy variables. 
Updated statistical methods based 
on feedback from the FDA. 
Change 20: Updated text in handling of dropouts or missing data section 
Section 14.7 
Updated the statistical approach to be used for missing data. 
Updated statistical methods based 
on feedback from the FDA. 
Change 21: Updated reference list 
References 
Deleted the following 2 references due to updates made in Section 14.7 Handling 
of dropouts or missing data: 
Mallinckrodt CH, Lin Q, Lipkovich I, Molenberghs G. A structured approach 
to choosing estimands and estimators in longitudinal clinical trials. Pharm 
Stat. 2012;11:456-61. 
Mallinckrodt CH. Preventing and Treating Missing Data in Longitudinal 
Clinical Trials: A Practical Guide. New York, NY: Cambridge University 
Press; 2013. 
Added the following 3 references, 1 for FACIT-Fatigue subscale and 2 for 
PASDAS: 
Cella D, Wilson H, Shalhoub H, et al. Content validity and psychometric 
evaluation of Functional Assessment of Chronic Illness Therapy-Fatigue in 
patients with psoriatic arthritis. J Patient Rep Outcomes. 2019;3(1):5. 
Coates LC, FitzGerald O, Mease PJ, et al. Development of a disease activity 
and responder index for psoriatic arthritis – Report of the Psoriatic Arthrits 
Module at OMERACT 11. J Rheumatol 2014;41:782-91. 
Coates LC, Gladman DD, Nash P, et al. Secukinumab provides sustained 
PASDAS-defined remission in psoriatic arthritis and improves health-related 
quality of life in patients achieving remission: 2-year results from the Phase 
Deleted Mallinckrodt references, as 
they are no longer applicable due to 
statistical updates. 
Additional references were 
deleted/added to support the 
assessments of FACIT-Fatigue 
subscale and PASDAS. 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 140 of 142 
Protocol section 
impacted 
Key components of previous 
protocol text 
Key components of revised protocol 
text 
Rationale 
III FUTURE 2 study. Arthritis Res Ther. 2018;20(1):272. doi: 
10.1186/s13075-018-1773-y. 
Deleted the following FACIT reference because it was superseded by the Cella 
et al, 2019 reference: 
Cella D, Yount S, Sorensen M, Chartash E, Sengupta N, Grober J. Validation 
of the Functional Assessment of Chronic Illness Therapy Fatigue Scale 
relative to other instrumentation in patients with rheumatoid arthritis. J 
Rheumatol. 2005;32:811–19. 
 
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 141 of 142 
19 
DECLARATION AND SIGNATURE OF INVESTIGATOR 
I confirm that I have carefully read and understood this protocol and agree to conduct this 
clinical study as outlined in this protocol, according to current Good Clinical Practice and local 
laws and requirements. 
I will ensure that all subinvestigators and other staff members read and understand all aspects of 
this protocol. 
I have received and read all study-related information provided to me. 
The objectives and content of this protocol as well as the results deriving from it will be treated 
confidentially and will not be made available to third parties without prior authorization by UCB. 
All rights of publication of the results reside with UCB, unless other agreements were made in a 
separate contract. 
Investigator: 
 
  
Printed name 
 Date/Signature 
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

UCB 
 
01 Apr 2021 
Clinical Study Protocol 
Bimekizumab 
PA0011 
 
 
 
Confidential 
Page 142 of 142 
20 
SPONSOR DECLARATION 
I confirm that I have carefully read and understand this protocol and agree to conduct this 
clinical study as outlined in this protocol and according to current GCP. 
 
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.

Approval Signatures
Name:
PA0011-protocol-amend-2
Version:
1. 0
Document Number:
CLIN-000171699
Title:
PA0011 Protocol-Amendment-2-Phase 3 - Placebo - controlled - Double-blind
Approved Date:
12 Apr 2021
Document Approvals
Approval
Verdict: Approved
Name: 
Capacity: Clinical
Date of Signature: 08-Apr-2021 13:33:04 GMT+0000
Approval
Verdict: Approved
Name: 
Capacity: Clinical
Date of Signature: 08-Apr-2021 17:24:32 GMT+0000
Approval
Verdict: Approved
Name: 
Capacity: Medical
Date of Signature: 12-Apr-2021 08:08:01 GMT+0000
PUBLIC COPY 
This document cannot be used to support any marketing authorization 
application and any extensions or variations thereof.