Pharmacokinetics and Pharmacodynamic Effects of Different Single Oral Doses of BI 474121 in Healthy Male Subjects
Phase: PHASE1
Conditions: Healthy
Sponsor: Boehringer Ingelheim

001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
Clinical Trial Protocol
TITLE PAGE
Document Number:
c30700234-04
EudraCT No.
2020-002321-28
BI Trial No.
1411-0013
BI Investigational
Medicinal Product
BI 474121
Title
Pharmacokinetics and pharmacodynamic effects of different 
single oral doses of BI 474121 in healthy male subjects
Lay Title
A study in healthy men to test how different doses of BI 474121 
are taken up and how they influence the amount of a molecular 
messenger (cGMP) in the spinal fluid
Clinical Phase
I
Clinical Trial Leader
Phone: 
Fax:
Principal 
Investigator
Phone: 
Fax:
Status
Final Protocol (Revised Protocol (based on global amendment 3))
Version and Date
Version: 4.0
Date: 03 May 2021
Page 1 of 78
Proprietary confidential information
© 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies. All rights reserved.
This document may not - in full or in part - be passed on, reproduced, published or otherwise used without prior written permission

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 2 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
CLINICAL TRIAL PROTOCOL SYNOPSIS
Company name
Boehringer Ingelheim
Protocol date
29 October 2020
Revision date
03 May 2021
BI trial number
1411-0013
Title of trial
Pharmacokinetics and pharmacodynamic effects of different single oral doses of 
BI 474121 in healthy male subjects 
Principal Investigator:
Trial site
Clinical phase
I
Trial rationale
BI 474121 is an inhibitor of phosphodiesterase 2 (PDE-2). 
Inhibition of PDE2 is expected to increase cyclic guanosine monophosphate 
(cGMP) in cerebrospinal fluid (CSF).
The trial is performed to obtain information about functional target engagement by 
measuring cGMP concentrations in CSF as basis for further clinical development of 
BI 474121 and to guide dose selection in future clinical trials.
Trial objectives

To evaluate the effect of BI 474121 on cGMP level in CSF

To assess the exposure of BI 474121 in CSF relative to plasma

To determine the exposure effect relationship in CSF with different oral doses 
of BI 474121
Trial design
Part 1 (DG 1): Single-blind, randomized, placebo-controlled 
Part 2 (DG 2): Open-label, non-randomized
Part 3 (DG 3-4): Open-label, randomized

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 3 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
Trial endpoints
Primary endpoints:

Maximum exposure-related* change from baseline (calculated as ratio) of 
cGMP in CSF 

Cmax ratio of BI 474121 in CSF compared to plasma
Secondary endpoints:

Maximum measured concentration (Cmax) of BI 474121 in plasma

Maximum measured concentration (Cmax) of BI 474121 in CSF

Time from dosing to maximum measured BI 474121 concentrations in 
plasma and CSF (tmax)

Maximum measured exposure-related* cGMP concentration in CSF
* time interval around tmax of BI 474121 in CSF
Number of subjects
total entered
24 subjects
each treatment
Part 1:10 subjects in DG 1 (6 subjects treatment B, 4 subjects treatment P)
Part 2: 6 subjects in DG 2 (6 subjects treatment A)
Part 3: 4 subjects in DG 3 (treatment C), 4 subjects in DG 4 (treatment D)
Diagnosis
Not applicable
Main criteria
for inclusion
Healthy male subjects, age of 18 to 65 years (inclusive), body mass index (BMI) of 
18.5 to 29.9 kg/m2 (inclusive)
Test product
BI 474121 uncoated tablets, tablet strengths: 2.5 mg, 10 mg
dose
Part 1: 20 mg (treatment B)
Part 2: 40 mg (treatment A)
Part 3: 10 mg (treatment C), 2.5 mg (treatment D)
mode of admin.
Oral with 240 mL of water after an overnight fast of at least 10 h
Duration of treatment
Single dose 
Reference product
Part 1 only: Matching Placebo to 10 mg BI 474121 (treatment P), uncoated tablets 
dose
Not applicable
mode of admin.
Oral with 240 mL of water after an overnight fast of at least 10 h
Duration of treatment
One day (single dose) 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 4 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
Statistical methods
The maximum exposure-related* cGMP change from baseline in CSF will be 
explored using an ANCOVA model, including ‘treatment’ as a factor and ‘cGMP 
value at baseline’ as covariate. 
The exposure of BI 474121 in CSF compared to plasma will be analysed with an 
ANOVA including the two factors ‘treatment’ and ‘pkmatrix’ (CSF versus plasma).
Dose proportionality of BI 474121 in plasma and CSF will be assessed using a 
power model.
Descriptive statistics will be calculated for all endpoints.
* time interval around tmax of BI 474121 in CSF

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 5 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
FLOW CHART
Period
Visit
Day
Planned time (relative to drug 
administration) [h:min]
Approximate clock time of actual 
day [h:min]
Event and comment
Safety laboratory10
Blood sampling for PK 
CSF sampling for PK and PD
In-house stay8
12-lead ECG
Medical Examinations
Vital signs (BP, PR)
Questioning for AEs and 
concomitant therapy 6
SCR
1
-21 to -2
Screening (SCR)1
xA
x
x7
x
-1
-24:00
09:00
Admission to the trial site
xB,5,12
▲
│
x
x7
x
x
-20:00
13:00
Lunch
│
-16:00
17:00
Snack
│
-14:00
19:00
Dinner
│
Treatment period
2
1
-2:00
07:00
Allocation to treatment 2
Placement of spinal 
catheter2
x2
x2,9
│
│
x2
x2
-1:00
08:00
x9
│
-0:10
08:50
x9
│
0:00
09:00
Drug administration11
│
0:15
09:15
x
│
0:30
09:30
x
x
│
1:00
10:00
x
x
│
x
1:30
10:30
x
x
│
2:00
11:00
240 mL fluid intake
x
x
│
x
3:00
12:00
x
x
│
4:00
13:00
240 mL fluid intake, there-
after lunch3
x
x
│
│
x
x
5:00
14:00
x
x
│
6:00
15:00
x
x
│
7:00
16:00
x
x
│
8:00
17:00
Snack (voluntary) 3
x
x
│
x
x
10:00
19:00
x
x
│
11:00
20:00
Dinner
│
12:00
21:00
x
x
│
14:00
23:00
x
x
│
x
2
24:00
09:00
Removal of spinal catheter,
Breakfast3
x B,12
x
x
│
│
x7
x
x
28:00
13:00
Lunch3
│
x
32:00
17:00
Snack (voluntary) 3
│
34:00
19:00
Dinner3
x
│
36:00
21:00
│
x
x
3
48:00
09:00
Confirmation of fitness, 
discharge from trial site, 
breakfast (voluntary)3
x
│
▼
x
x7
x
x
4
72:00
09:00
Ambulatory visit
x B
x
x7
x
x
FU
3
8 to 14
End of trial (EoTrial)4
xC
x
x
x
x

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 6 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
1.
Subject must be informed and written informed consent obtained prior to starting any screening procedures. Screening 
procedures include physical examination, check of vital signs, ECG, safety laboratory (including drug screening), 
demographics (including determination of body height and weight, smoking status and alcohol history), relevant medical 
history, concomitant therapy and review of inclusion/exclusion criteria.
2.
The time is approximate; the procedure is to be performed and completed within the 3 h prior to drug administration.
3.
If several actions are indicated at the same time, the intake of meals will be the last action.
4.
At the end of trial visit the EoTrial medical examination includes physical examination, vital signs, ECG, safety 
laboratory, recording of AEs and concomitant therapies, and visual inspection of lumbar puncture site.
5.
Safety lab includes urine drug screening and alcohol breath test
6.
AEs and concomitant therapies will be recorded throughout the trial, but will be specifically asked for at the times 
indicated in the Flow Chart above. Depending on local procedures at the trial site, a more frequent AE/CT questioning 
may be performed but not less.
7.
At screening or on day -1, prior to subjects’ inclusion into the study, fundoscopy using an ophthalmoscope will be 
performed as part of the medical examination. 
On day -1 and on day 2-4, the medical examination includes a symptom-directed physical examination. 
On day 2-4, additionally a visual inspection of the lumbar puncture site is performed.
8.
The subjects remain inhouse from day -1 to day 3. 
9. 
The planned times for the baseline CSF samples are an approximate. The first one is taken in the context of spinal catheter 
placement, the last one within 10 minutes prior to drug administration and one sample in the interval between the first and 
the last sample.
10. Letters A, B, and C define different sets of safety lab tests (for details refer to Section 5.2.3)
11. Administration of trial medication will be performed after subjects have fasted overnight; fasting is to start no less than 
10 h before the scheduled dosing. From 1 h before drug intake until lunch, fluid intake is restricted to the water 
administered with the drug, and an additional 240 mL of water at 2 h and 4 h post-dose. No food is allowed for at least 4 h 
after drug intake (see Section 4.2.2.2).
12. Safety lab includes severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) swab test.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 7 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
TABLE OF CONTENTS
TITLE PAGE ......................................................................................................1
CLINICAL TRIAL PROTOCOL SYNOPSIS ................................................2
FLOW CHART...................................................................................................5
TABLE OF CONTENTS ...................................................................................7
ABBREVIATIONS.......................................................................................... 11
1.
INTRODUCTION.................................................................................... 14
1.1
MEDICAL BACKGROUND............................................................................14
1.3
RATIONALE FOR PERFORMING THE TRIAL........................................23
1.4
BENEFIT - RISK ASSESSMENT ...................................................................23
2.
TRIAL OBJECTIVES AND ENDPOINTS........................................... 28
2.1
MAIN OBJECTIVES, PRIMARY AND SECONDARY ENDPOINTS ......28
2.1.1
Main objectives......................................................................................28
2.1.2
Primary endpoints ................................................................................28
2.1.3
Secondary endpoints.............................................................................28
2.2.2.2
Safety and tolerability..............................................................30
3.
DESCRIPTION OF DESIGN AND TRIAL POPULATION.............. 31
3.1
OVERALL TRIAL DESIGN AND PLAN ......................................................31
3.2
DISCUSSION OF TRIAL DESIGN, INCLUDING THE CHOICE OF 
CONTROL GROUP..........................................................................................33
3.3
SELECTION OF TRIAL POPULATION ......................................................34
3.3.1
Main diagnosis for trial entry..............................................................34
3.3.2
Inclusion criteria...................................................................................34
3.3.3
Exclusion criteria ..................................................................................34
3.3.4
Withdrawal of subjects from treatment or assessments ...................36

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 8 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
3.3.4.1
Discontinuation of trial treatment ............................................37
3.3.4.2
Withdrawal of consent to trial participation ............................37
3.3.4.3
Discontinuation of the trial by the sponsor..............................37
3.3.5
Replacement of subjects .......................................................................38
4.
TREATMENTS........................................................................................ 39
4.1
INVESTIGATIONAL TREATMENTS ..........................................................39
4.1.1
Identity of the Investigational Medicinal Products ...........................39
4.1.2
Selection of doses in the trial................................................................40
4.1.3
Method of assigning subjects to treatment groups ............................40
4.1.4
Drug assignment and administration of doses for each subject .......40
4.1.5
Blinding and procedures for unblinding ............................................41
4.1.6
Packaging, labelling, and re-supply ....................................................41
4.1.7
Storage conditions.................................................................................41
4.1.8
Drug accountability ..............................................................................42
4.2
OTHER TREATMENTS, EMERGENCY PROCEDURES, 
RESTRICTIONS ...............................................................................................42
4.2.1
Other treatments and emergency procedures....................................42
4.2.2
Restrictions............................................................................................43
4.2.2.1
Restrictions regarding concomitant treatment .........................43
4.2.2.2
Restrictions on diet and life style.............................................43
4.3
TREATMENT COMPLIANCE.......................................................................44
5.
ASSESSMENTS....................................................................................... 45
5.1
ASSESSMENT OF EFFICACY.......................................................................45
5.2
ASSESSMENT OF SAFETY............................................................................45
5.2.1
Medical examination.............................................................................45
5.2.2
Vital signs...............................................................................................45
5.2.3
Safety laboratory parameters..............................................................45
5.2.4
Electrocardiogram................................................................................48
5.2.5
Assessment of adverse events...............................................................49
5.2.5.1
Definitions of adverse events...................................................49
Adverse event ............................................................49
Serious adverse event ................................................49
AEs considered ‘Always Serious’.............................49
Adverse events of special interest .............................50
Intensity (severity) of AEs.........................................51
Causal relationship of AEs ........................................51
5.2.5.2
Adverse event collection and reporting ...................................52
AE collection.............................................................52
AE reporting to the sponsor and timelines ................53
Information required..................................................53
Pregnancy ..................................................................53
5.3
DRUG CONCENTRATION MEASUREMENTS AND 
PHARMACOKINETICS..................................................................................53

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 9 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
5.3.1
Assessment of pharmacokinetics .........................................................53
5.3.2
Methods of sample collection...............................................................54
5.3.2.1
Blood sampling for pharmacokinetic analysis.........................54
5.3.2.2
CSF sampling for pharmacokinetic analysis............................54
5.3.4
Pharmacokinetic - pharmacodynamic relationship...........................55
5.4
ASSESSMENT OF BIOMARKERS................................................................56
5.4.1
Method and timing of sample collection.............................................56
5.4.1.1
CSF sampling for pharmacokinetic and pharmacodynamic 
analysis ...................................................................................56
5.5
BIOBANKING ...................................................................................................57
5.6
OTHER ASSESSMENTS .................................................................................57
5.7
APPROPRIATENESS OF MEASUREMENTS.............................................57
6.
INVESTIGATIONAL PLAN.................................................................. 58
6.1
VISIT SCHEDULE............................................................................................58
6.2
DETAILS OF TRIAL PROCEDURES AT SELECTED VISITS ................58
6.2.1
Screening period....................................................................................58
6.2.2
Treatment period ..................................................................................58
6.2.3
Follow-up period and trial completion ...............................................59
7.
STATISTICAL METHODS AND DETERMINATION OF
SAMPLE SIZE......................................................................................... 60
7.1
STATISTICAL DESIGN – MODEL ...............................................................60
7.2
NULL AND ALTERNATIVE HYPOTHESES ..............................................60
7.3
PLANNED ANALYSES....................................................................................60
7.3.1
General considerations.........................................................................60
7.3.2
Primary endpoint analyses...................................................................62
7.3.3
Secondary endpoint analyses ...............................................................63
7.3.5
Safety analyses.......................................................................................64
7.4
INTERIM ANALYSIS ......................................................................................65
7.5
HANDLING OF MISSING DATA ..................................................................66
7.5.1
Safety......................................................................................................66
7.5.2
Pharmacokinetics..................................................................................66
7.5.3
Pharmacodynamics...............................................................................66
7.6
RANDOMISATION ..........................................................................................66
7.7
DETERMINATION OF SAMPLE SIZE ........................................................66

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 10 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
8.
INFORMED CONSENT, TRIAL RECORDS, DATA 
PROTECTION, PUBLICATION POLICY, AND 
ADMINISTRATIVE STRUCTURE...................................................... 67
8.1
TRIAL APPROVAL, SUBJECT INFORMATION, INFORMED 
CONSENT ..........................................................................................................67
8.2
DATA QUALITY ASSURANCE .....................................................................68
8.3
RECORDS..........................................................................................................68
8.3.1
Source documents .................................................................................68
8.3.2
Direct access to source data and documents.......................................69
8.3.3
Storage period of records.....................................................................69
8.4
EXPEDITED REPORTING OF ADVERSE EVENTS .................................70
8.5
STATEMENT OF CONFIDENTIALITY AND SUBJECT PRIVACY.......70
8.5.1
Collection, storage and future use of biological samples and 
corresponding data ...............................................................................70
8.6
TRIAL MILESTONES .....................................................................................70
8.7
ADMINISTRATIVE STRUCTURE OF THE TRIAL ..................................71
9.
REFERENCES......................................................................................... 72
9.1
PUBLISHED REFERENCES...........................................................................72
9.2
UNPUBLISHED REFERENCES.....................................................................72
10. APPENDICES .......................................................................................... 74
10.1
COVID-19 RISK ASSESSMENT AND MITIGATION STRATEGIES......74
10.1.1 COVID-19 RISK ASSESSMENT........................................................74
10.1.2 COVID-19 RISK MITIGATION MEASURES.................................75
11. DESCRIPTION OF GLOBAL AMENDMENTS................................. 76
11.1
GLOBAL AMENDMENT 1 .............................................................................76
11.2
GLOBAL AMENDMENT 2 .............................................................................77
11.3
GLOBAL AMENDMENT 3 .............................................................................78

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 11 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
ABBREVIATIONS
AD
Alzheimer’s disease
AE
Adverse event
AESI
Adverse events of special interest
ANOVA
Analysis of variance
AUC0-∞
Area under the concentration-time curve of the analyte in plasma over the 
time interval from 0 extrapolated to infinity
%AUCtz-∞
Percentage of AUC0-∞ obtained by extrapolation
AUCt1-t2
Area under the concentration-time curve of the analyte in plasma over the 
time interval t1 to t2
AUC0-tz
Area under the concentration-time curve of the analyte in plasma over the 
time interval from 0 to the last quantifiable data point
AUEC0-tz
Area under the biomarker effect vs. time curve over the time interval 
from 0 to the last quantifiable data point
BA
Bioavailability
BI
Boehringer Ingelheim
BLQ
Below limit of quantification
BMI
Body mass index (weight divided by height squared)
BP
Blood pressure
CA
Competent authority
cAMP
Cyclic adenosine monophosphate
cGMP
Cyclic guanosine monophosphate
CIAS
Cognitive impairment associated with schizophrenia
CI
Confidence interval
CKD-EPI
Chronic kidney disease epidemiology collaboration
CL/F
Apparent clearance of the analyte in plasma after extravascular 
administration
Cmax
Maximum measured concentration of the analyte in plasma or CSF
CNS
Central nervous system
COVID
Corona virus disease 2019
CTM
Clinical Trial Monitor
CRF
Case Report Form, paper or electronic (sometimes referred to as ‘eCRF’)
CSF
Cerebrospinal fluid
CTL
Clinical Trial Leader
CTP
Clinical trial protocol
CTR
Clinical trial report

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 12 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
CV
Arithmetic coefficient of variation
DG
Dose group
DILI
Drug induced liver injury
ECG
Electrocardiogram
eCRF
Electronic case report form
eDC
Electronic data capture 
EDTA
Ethylenediaminetetraacetic acid
eGFR
Estimated glomerular filtration rate
EoTrial
End of trial
EudraCT
European Clinical Trials Database
F
Absolute bioavailability factor
FAS
Full Analysis Set
FDA
Food and Drug Administration
FIH
First in Human
FU
Follow-up
GCP
Good Clinical Practice
gCV
Geometric coefficient of variation
gMean
Geometric mean
HR
Heart rate
IB
Investigator’s brochure
ICF
Informed Consent Form
IEC
Independent Ethics Committee
IPD
Important protocol deviation
IRB
Institutional Review Board
ISF
Investigator site file
z
Terminal rate constant of the analyte in plasma or CSF
LC-MS/MS
Liquid chromatography with tandem mass spectrometry
LLOQ
Lower limit of quantification
MDA
Methylenedioxyamphetamine
MDMA
Methylenedioxymethamphetamine
MedDRA
Medical Dictionary for Regulatory Activities
MRTpo
Mean residence time of the analyte in the body after po
administration
NMDA
N-methyl-D-aspartate
NOAEL
No adverse effect level
PCR
Polymerase chain reaction
PD
Pharmacodynamics

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 13 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
PDE-2
PhosphoDiEsterase 2
PDS
Pharmacodynamic set
PE
Polyethylene
PfOS
Powder for reconstitution of an oral solution
PK
Pharmacokinetic(s)
PKS
Pharmacokinetic set
PoPP
Proof of Pharmacological Principle
PP
Polypropylene
PR
Pulse rate
p.o.
Per os, oral administration
QT
Time between start of the Q-wave and the end of the T-wave in an 
electrocardiogram
QTc
QT interval corrected for heart rate using the method of Fridericia (QTcF) 
or Bazett (QTcB)
REP
Residual effect period
SAE
Serious adverse event
SARS-CoV-2
Severe acute respiratory syndrome coronavirus 2
SCR
Screening
SOP
Standard operating procedure
SRD
Single-rising dose
ss
(at) steady state
SUSAR
Suspected unexpected serious adverse reaction
TMF
Trial master file
t1/2
Terminal half-life of the analyte in plasma
tmax
Time from (last) dosing to the maximum measured concentration of the 
analyte in plasma or CSF
TS
Treated set
tz
Time of last measurable concentration of the analyte in plasma or CSF
TDMAP
Trial Data Management and Analysis Plan
TSAP
Trial statistical analysis plan
ULN
Upper limit of normal
Vz/F
Apparent volume of distribution during the terminal phase after 
extravascular administration
XTC
Ecstasy 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 14 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
1.
INTRODUCTION
 
1.1
MEDICAL BACKGROUND
AD and schizophrenia are chronic, severe, and disabling brain disorders affecting both men 
and women. Available symptomatic treatments for AD consist of acetylcholinesterase 
inhibitors (AChEIs) and memantine which, however, are widely acknowledged as having very 
limited efficacy. More effective symptomatic treatment remains a major unmet medical need. 
Existing treatment options for schizophrenia (i.e., first- and second-generation antipsychotics) 
are primarily efficacious in treating positive symptoms, but have limited efficacy for treating 
the cognitive and negative symptoms of the disorder. No pharmacologic therapies have been 
approved for the symptomatic treatment of the cognitive impairment seen in patients with 
schizophrenia. 
Schizophrenia and AD are characterized by abnormalities in glutamatergic pathways related to 
N-methyl-D-aspartate (NMDA) receptor hypofunction in cortical and hippocampal brain areas 
[R13-4518]; [R13-4521]. These abnormalities are hypothesized to lead to negative symptoms 
and cognitive impairment in schizophrenia and cognitive impairment in AD. NMDA receptor 
activation triggers a cascade of intracellular, post-synaptic signalling events through elevation 
of second messengers such as cyclic adenosine monophosphate (cAMP) and cyclic guanosine 
monophosphate (cGMP) with subsequent activation of protein kinases and manifestation of 
synaptic plasticity determined by long term potentiation (LTP), key processes underlying
learning and memory formation [R10-5092], [R10-5102].
PDE2 inhibitors increase the neuronal pre-synaptic levels of the cyclic nucleotides cAMP and 
cGMP, thus increasing synaptic function by facilitating glutamate release upon action potential 
in brain regions involved in learning and memory. This results in a functional potentiation of 
glutamatergic neurotransmission, NMDA receptor function and synaptic plasticity, and 
consequently, should lead to cognitive improvement in patients with AD or schizophrenia. 
Enhancement of cognitive functions is expected to reduce the disease burden and improve the
quality of life (QoL) in affected patients.
 
 
 
 
 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 15 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 16 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 17 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 18 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 19 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 20 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 21 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 22 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 23 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
1.3
RATIONALE FOR PERFORMING THE TRIAL
BI 474121 is an inhibitor of phosphodiesterase 2 (PDE-2). Inhibition of PDE2 is expected to 
increase cGMP in CSF.
 
 
Therefore, this trial is designed to obtain information about functional target engagement by 
measuring cGMP concentrations in CSF as basis for further clinical development and to guide 
dose selection in future clinical trials.
 
 
1.4
BENEFIT - RISK ASSESSMENT
Participation in this clinical trial is without any (therapeutic) benefit for healthy subjects. Their 
participation, however, is of major importance for the development of BI 474121 as a 
treatment for AD and CIAS. Subjects are exposed to risks of study procedures and risks related 
to the exposure to the trial medication. These risks as well as the safety measures for risk 
mitigations are described below. 
Procedure-related risks
Subjects participating in the trial will undergo a serial CSF sampling via an indwelling spinal 
catheter. The most common adverse events associated with the serial CSF sample collection 
are headache, nausea, light headedness, retro-ocular pressure sensation, dizziness, muscle pain 
of the lower back, neck pain, back pain, catheter site pain, back discomfort and tenderness of 
the spinal catheter insertion site [R20-0666]. 
However, the procedure is potentially associated with rare but more severe adverse events, 
such as epidural infection, meningitis, spinal cord or nerve root trauma, spinal/epidural 
hematoma and cerebral herniation [R20-2943].
In this publication [R20-0666], the procedural-related risks are summarized with focus on 
procedural (i.e. post-spinal) headache:
In 71 subjects (25 females, 56 males), mean age 45 years, 24 (33.8%) subjects experienced 
post-spinal headache. The mean duration of headache was 120 hours. Thirteen (18.3%) 
subjects required an epidural blood patch. Sciatic pain, paraesthesia and muscle cramping were 
noted as adverse events in subjects where a spinal catheter was placed. Specifically, after 24 h 
serial CSF sampling regime procedural headache is reported as 16 out of 43 subjects (37.2%). 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 24 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
The total volume of sampled CSF during this entire trial will be not more than 50 mL. It is 
expected that in a healthy subject the collected CSF volume will be completely substituted via 
arachnoidal production as the rate of CSF production is about 500 mL/day.
The use of an indwelling venous catheter or venepuncture for e.g. blood sampling may result in
mild bruising, and in rare cases, in transient inflammation of the wall of the vein, or nerve 
injury, potentially resulting in paraesthesia, reduced sensibility, and/or pain for an indefinite 
period.
The total volume of blood withdrawn per subject during the entire study will not exceed the 
volume of a normal blood donation (500 mL). No health-related risk to healthy subjects is 
expected from withdrawal of this volume of blood.
Drug-related risks

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 25 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
Although rare, a potential for drug-induced liver injury (DILI) is under constant surveillance 
by sponsors and regulators. Therefore, this trial requires timely detection, evaluation, and 
follow-up of laboratory alterations in selected liver laboratory parameters to ensure subjects´ 
safety; see also Section 5.2.5.1.4, adverse events of special interest.
SARS-CoV-2 related risks
Due to the SARS-CoV-2 pandemic, there is a risk of infection for subjects. 
Guidance related to COVID-19 infection and risk assessment for trials with BI 474121 is 
provided in the IB [c26859058]. 
 
 
 Appropriate risk minimization measures are to be taken in accordance 
with the public health precautions implemented in the country where the study will be 
conducted (see Section 10.1.)
Safety measures
The safety measures in this trial address both drug- and procedure-related risks. 
Trial design

The design involves sequential dosing of dose groups with up to two preliminary data 
analyses to decide about the further conduct of the trial (see flow diagram of trial conduct 
in Figure 1.4: 1). Depending on the preliminary data analyses, a trial part may be omitted or 
the trial may be terminated. Hence, by this trial design, the number of subjects exposed to 
drug- and procedure-related risks is limited. A detailed description of the trial design is 
provided in Section 3.1.

Careful dose selection in first DG: 
20 mg BI 474121 was selected as dose in DG 1 since it might provide early evidence about 
 
 
 
 
 

Split in cohorts within a trial part
For safety reasons, no more than 3 subjects will receive treatment on the same day in any 
given trial part. 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 26 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
PoPP = Proof of Pharmacological Principle
Figure 1.4: 1 Flow diagram of trial conduct
Part I (randomized single-blind placebo-controlled)
Preliminary data analysis
BI 474121 (20 mg), 6 subjects 
Placebo, 4 subjects
Part III (randomized open-label)
BI 474121 (2.5 mg), 4 
subjects 
BI 474121 (10 mg), 4 
subjects 
PoPP
No PoPP
Part II (non-randomized open-label)
PoPP
Preliminary data analysis
BI 474121 (40 mg), 6 subjects 
No PoPP
Stop the trial

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 27 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
Site selection
The site has been selected according to their experience with the serial CSF sampling 
technique
Spinal catheterization and CSF sampling

Definition of enrolment criteria to decrease the likelihood of enrolling individuals 
susceptible to procedural complications

Placement of catheter will be performed by an anesthesiologist or neurologist according 
to standard procedures at the trial site [c34094265]

Placement of the catheter and collection of the CSF samples will be performed under 
strict aseptic conditions to minimize the risk of infections

Special spinal catheters will be used to prevent CSF leakage [c34094265]

Proper hydration of subjects will be ensured

Regular visual inspection of catheter insertion site for signs of infection or CSF leakage

Restriction of total CSF sampling volume to 50 mL at maximum 
Summary:
Overall, BI 474121 has the potential to become a treatment of AD and CIAS.
 
 
 
.
Considering the medical need of the development of a safer and effective treatment for AD and 
CIAS, the sponsor feels that the benefit of this trial outweighs the potential risks and justifies 
exposure of healthy subjects.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 28 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
2.
TRIAL OBJECTIVES AND ENDPOINTS
2.1
MAIN OBJECTIVES, PRIMARY AND SECONDARY ENDPOINTS
2.1.1
Main objectives
The main objective of this trial is 

To evaluate the effect of BI 474121 on cGMP levels in CSF

To assess the exposure of BI 474121 in CSF relative to plasma

To determine the exposure effect relationship in CSF with different oral doses of 
BI 474121 
2.1.2
Primary endpoints
The following pharmacodynamic parameters will be determined

Maximum exposure-related* change from baseline (calculated as ratio) of cGMP in 
CSF (see Section 7.3.1)
The following pharmacokinetic parameters will be determined for BI 474121:

Cmax ratio of BI 474121 in CSF compared to plasma
2.1.3
Secondary endpoints

Maximum measured concentration (Cmax) of BI 474121 in plasma

Maximum measured concentration (Cmax) of BI 474121 in CSF

Time from dosing to maximum measured BI 474121 concentrations in plasma and CSF 
(tmax)

Maximum measured exposure-related* cGMP concentration in CSF
____________________
* time interval around tmax of BI 474121 in CSF

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 29 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 30 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
2.2.2.2
Safety and tolerability
Safety and tolerability of BI 474121 will be assessed based on:

Adverse events (including clinically relevant findings from the physical examination)

Safety laboratory tests

12-lead ECG

Vital signs (blood pressure, pulse rate)

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 31 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
3.
DESCRIPTION OF DESIGN AND TRIAL POPULATION
3.1
OVERALL TRIAL DESIGN AND PLAN
In this trial, up to three parts will be conducted, depending on analyses of preliminary data (see 
Figure 3.1: 1 and Figure 1.4: 1).
Figure 3.1: 1 Flow diagram of trial conduct
The dose groups are outlined in Table 3.1: 1 below.
Table 3.1: 1
Dose groups
Part 1
Part 2
Part 3
Dose Group (DG)
1
2
3
4
Treatment
B
P
Preliminary data analysis
A
Preliminary data analysis
C
D
Number of subjects on BI 474121 6
0
6
4
4
Number of subjects on placebo
0
4
0
0
0
BI 474121 dose (mg)
20 
-
40
10
2.5
Trial design
Randomized single-
blind
placebo-controlled
Non-
randomized
open-label
Randomized
open-label
For safety reasons, no more than 3 subjects will receive treatment on the same day in any given
trial part. The time interval between drug administrations per day is not specified and solely 
Part 1 (randomized 
single-blind placebo-controlled)
Placebo
4 subjects
BI 474121
DG 1 (20 mg)
6 subjects
BI 474121
DG 2 (40 mg)
6 subjects
Part 2
(non-randomized open-label)
Preliminary data analysis
BI 474121
DG 3 (10 mg)
4 subjects
BI 474121
DG 4 (2.5 mg)
4 subjects
Part 3
(randomized open-label)
Preliminary data analysis

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 32 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
depends on the logistical setup at the trial site. 
An overview of all relevant trial activities is provided in the Flow Chart. For visit schedule and 
details of trial procedures at selected visits, refer to Sections 6.1 and 6.2, respectively.
Conduct of Part 1 (20 mg BI 474121 or placebo)
10 subjects will receive randomized treatment, 6 subjects on active, 4 subjects on placebo.
After DG 1 (20 mg BI 474121 or placebo), a documented data review based on an analysis of 
preliminary data (see Section 7.4) will take place to decide whether to continue with Part 2 or 
Part 3 of the trial (see Figure 1.4: 1). The decision will be taken based on PD, PK and safety 
criteria.
PD criterion (see criterion 1, Section 3.3.4.3):
If the desired PD effect is observed after administration of 20 mg BI 474121, the trial continues 
with Part 3 (given the observed safety profile allows to proceed), i.e. Part 2 will be omitted.
If the desired PD effect is not observed after administration of 20 mg BI 474121, the trial may 
continue with Part 2 (DG 2, 40 mg), if the following PK and safety criteria are fulfilled. 
PK criteria:
-
none of the individual observed exposure values in DG 1 exceeded the maximum 
acceptable exposure, 
 
-
systemic exposure of DG 2 (
 
 is not expected to exceed the maximum acceptable exposure, 
 
Safety criterion:
-
DG 1 (20 mg) was safe and showed acceptable tolerability
Minimum data set to be reviewed after Part 1 (DG 1, 20 mg) for escalating to Part 2
PD data from at least 4 subjects on active and at least 3 subjects on placebo need to be 
evaluated to assess the PD effect after trial Part 1.
If the desired PD effect is not observed in Part 1, the following minimum data from 4 subjects 
on active need to be evaluated to assess whether it is safe to proceed to Part 2 (40 mg) based on 
the assessment of

PK in plasma up to at least 24 hours post dosing

Adverse events, vital signs, ECG, safety lab up to at least 24 hours post dosing
Conduct of Part 2 (DG 2, 40 mg BI 474121) – if applicable:
6 subjects will receive non-randomized treatment, all subjects on active. 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 33 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
After DG 2 (40 mg) a documented data review based on an analysis of preliminary data (see 
Section 7.4) will take place to decide whether to continue with Part 3 or to terminate the trial
(see Figure 1.4: 1 and Section 3.3.4.3). 
If the desired PD effect is observed after administration of 40 mg BI 474121, the trial continues 
with Part 3 given the observed safety profile allows to proceed.
If the desired PD effect is not observed after administration of 40 mg BI 474121, the sponsor 
reserves the right to terminate the trial.
Minimum data set to be reviewed after Part 2 (DG 2, 40 mg BI 474121)
Data from at least 4 subjects on active (from DG 2) and at least 3 subjects on placebo (from 
DG 1) needs to be evaluated to assess the PD effect.
For safety data, no minimum data set is specified, since in Part 3 of the trial lower doses are 
administered. However, the documented data review includes the review of all available safety 
data.
The decision about the further conduct of the trial based on the preliminary data analysis will 
be made jointly by the Principal Investigator (PI), the Team Member Medicine (TMM), and 
the Clinical Trial Leader (CTL) or their respective authorised deputy. The documented data
reviews may be conducted by video/telephone conference. The CTL is responsible for the 
organisation and minutes of the reviews. Minutes will be signed off by the PI (or an authorised 
deputy), the CTL (or authorised deputy), and the TMM and will be filed in the ISF and TMF. 
Conduct of Part 3 (DG 3, 10 mg BI 474121 and DG 4, 2.5 mg BI 474121) – if applicable: 
8 subjects will receive randomized treatment, all subjects on active, 4 subjects in DG 3 (10 mg) 
and 4 subjects in DG 4 (2.5 mg). 
3.2
DISCUSSION OF TRIAL DESIGN, INCLUDING THE CHOICE OF 
CONTROL GROUP
The design described in Section 3.1. was chosen to support with two pre-defined preliminary 
data analyses early decision(s) about further trial conduct (see Figure 1.4:1). This approach 
seeks to avoid that subjects are unnecessarily exposed to drug- and procedure-related risks.
With the same consideration (i.e. reducing the number of subjects exposed to drug- und 
procedure-related risks), placebo subjects were only included in Part 1 of the trial. 
Since no sequence effects are expected, it appears acceptable to use the placebo subjects from 
Part 1 for the PD assessment in Part 2. 
The open-label treatment in Parts 2 and 3 of the trial is not expected to bias results, since the 
primary and secondary study endpoints are derived from measurement of plasma and CSF 
concentrations of the analytes and placebo subjects from part 1 serve as control.
 
 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 34 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
 
 
3.3
SELECTION OF TRIAL POPULATION
It is planned that at maximum 24 healthy male subjects will enter the study. They will be 
recruited from the volunteers' pool of the trial site.
Only male subjects will be included in the study because no data on reproductive toxicology 
are available at this time.
A log of all subjects enrolled into the trial (i.e. who have signed informed consent) will be 
maintained in the ISF irrespective of whether they have been treated with investigational drug 
or not.
3.3.1
Main diagnosis for trial entry
The study will be performed in healthy male subjects.
3.3.2
Inclusion criteria
Subjects will only be included in the trial if they meet the following criteria:
1. Healthy male subjects according to the assessment of the investigator, as based on a 
complete medical history including a physical examination, vital signs (BP, PR), 12-lead 
ECG, and clinical laboratory tests 
2. Age of 18 to 65 years (inclusive) 
3. BMI of 18.5 to 29.9 kg/m2 (inclusive) 
4. Signed and dated written informed consent prior to admission to the study, in accordance 
with GCP and local legislation
3.3.3
Exclusion criteria
Subjects will not be allowed to participate if any of the following general criteria apply:
1. Any finding in the medical examination (including BP, PR or ECG) deviating from normal 
and assessed as clinically relevant by the investigator
2. Repeated measurement of systolic blood pressure outside the range of 90 to 150 mmHg, 
diastolic blood pressure outside the range of 50 to 90 mmHg, or pulse rate outside the range 
of 45 to 90 bpm
3. Any laboratory value outside the reference range that the investigator considers to be of 
clinical relevance
4. Any evidence of a concomitant disease assessed as clinically relevant by the investigator
5. Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or 
hormonal disorders assessed as clinically relevant by the investigator

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 35 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
6. Cholecystectomy or other surgery of the gastrointestinal tract that could interfere with the 
pharmacokinetics of the trial medication (except appendectomy or simple hernia repair)
7. Diseases of the central nervous system (including but not limited to any kind of seizures or 
stroke), and other relevant neurological or psychiatric disorders 
8. History of relevant orthostatic hypotension, fainting spells, or blackouts
9. Chronic or relevant acute infections
10. History of relevant allergy or hypersensitivity (including allergy to the trial medication or 
its excipients) 
11. Use of drugs within 30 days of planned administration of trial medication that might 
reasonably influence the results of the trial (including drugs that cause QT/QTc interval
prolongation)
12. Intake of an investigational drug in another clinical trial within 30 days of planned 
administration of investigational drug in the current trial, or concurrent participation in 
another clinical trial in which investigational drug is administered
13. Smoker (more than 10 cigarettes or 3 cigars or 3 pipes per day)
14. Inability to refrain from smoking on specified trial days
15. Alcohol abuse (consumption of more than 30 g or 3 alcoholic units per day)
16. Drug abuse or positive drug screening
17. Blood donation of more than 100 mL within 30 days of planned administration of trial 
medication or intended blood donation during the trial
18. Intention to perform excessive physical activities within one week prior to the 
administration of trial medication or during the trial
19. Inability to comply with the dietary regimen of the trial site
20. A marked baseline prolongation of QT/QTc interval (such as QTc intervals that are 
repeatedly greater than 450 ms in males) or any other relevant ECG finding at screening
21. A history of additional risk factors for Torsade de Pointes (such as heart failure, clinically 
relevant hypokalaemia, or family history of Long QT Syndrome)
22. Subject is assessed as unsuitable for inclusion by the investigator, for instance, because the 
subject is not considered able to understand and comply with study requirements, or has a 
condition that would not allow safe participation in the study 
23. Male subjects with WOCBP partner who are unwilling to use a highly effective method of 
birth control from time point of administration of trial medication until 90 days thereafter. 
Highly effective methods of birth control are:
- Male subject is sexually abstinent
- Male subjects is vasectomised (vasectomy at least 1 year prior to enrolment), plus
condom in male subject
- Use of intrauterine device (IUD) or intrauterine hormone-releasing system (IUS)
- Use of progestogen-only hormonal contraception by female partner that inhibits 
ovulation (only injectables or implants), plus condom in male subject
- Use of combined (estrogen and progestogen containing) hormonal contraception by 
female partner that prevents ovulation (oral, intravaginal or transdermal), plus condom
in male subject

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 36 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
- Female partner is surgically sterilised (including hysterectomy)
- Female partner is postmenopausal, defined as no menses for 1 year without an 
alternative medical cause (in questionable cases a blood sample with FSH above 40 
U/L and estradiol below 30 ng/L is confirmatory)
Sperm donation is not allowed from the time point of drug administration until 90 days 
thereafter.
In addition, the following trial-specific exclusion criteria apply:
24. ALT (alanine transaminase), AST (aspartate transaminase), exceed 1.5 x upper limit of 
normal range at screening, confirmed by a repeat test
25. Estimated glomerular filtration rate (eGFR) according to CKD-EPI formula below or equal 
60 ml/min at screening, confirmed by a repeat test
26. History of migraine or other types of headache more than twice/month, history of 
intervertebral disc disease or chronic significant low back pain
27. Use of blood thinning compounds within 10 days (for low and high molecular weight 
heparins, aspirin) and within 30 days (for all other drugs with anticoagulatory effects) of 
spinal catheter placement 
28. History or presence of head injuries with documented loss of consciousness 
for >5 minutes
29. History of spinal cord compression
30. An infection or inflammation of the skin in or in close proximity to the area of the lumbar 
puncture site or has absolute or relative anatomic abnormalities that would be a 
contraindication to lumbar puncture
31. Spinal surgery and spinal deformities incompatible with lumbar puncture and/or spinal 
catheter insertion. Microdiscectomy procedures are allowed.
32. Signs of increased intracranial pressure as determined by fundoscopy
In addition, the following SARS-CoV-2 specific exclusion criterion applies
33. A positive PCR test for SARS-CoV-2 and clinical symptoms suggestive for this disease at 
Day -1
For study restrictions, refer to Section 4.2.2.
3.3.4
Withdrawal of subjects from treatment or assessments
Subjects may discontinue trial treatment or withdraw consent to trial participation as a whole 
(‘withdrawal of consent’) with very different implications; please see Sections 3.3.4.1 and 
3.3.4.2 below.
If a subject is removed from or withdraws from the trial prior to the administration of trial 
medication, the data of this subject will not be entered in the case report form (CRF) and will 
not be reported in the clinical trial report (CTR). If a subject is removed from or withdraws 
from the trial after the administration of trial medication, this will be documented and the 
reason for discontinuation must be recorded in the CRF; in addition, the data will be included 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 37 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
in the CRF and will be reported in the CTR. At the time of discontinuation, a complete end of
trial examination will be performed, if possible, and the information will be recorded in the 
CRF. If the discontinuation occurs before the end of the REP (see Section 1.2.2), the 
discontinued subject should if possible be questioned for AEs and concomitant therapies at or 
after the end of the REP in order to ensure collection of AEs and concomitant therapies 
throughout the REP, if not contrary to any consent withdrawal of the subject.
Since the risks of drug exposure of a (pregnant) female partner of a male study participant via 
the seminal fluid are yet unknown, adequate contraception as outlined in Section 3.3.3 is a 
prerequisite for participation in the study.
3.3.4.1
Discontinuation of trial treatment
An individual subject will discontinue trial treatment if:
1. The subject wants to discontinue trial treatment, without the need to justify the decision
2. The subject has repeatedly shown to be non-compliant with important trial procedures and, 
in the opinion of both, the investigator and sponsor representative, is not willing or able to 
adhere to the trial requirements in the future.
3. The subject needs to take concomitant medication that interferes with the investigational 
medicinal product or other trial treatment
4. The subject can no longer receive trial treatment for medical reasons (such as surgery, 
adverse events [AEs], or diseases)
5. The subject has an elevation of AST and/or ALT ≥3-fold ULN and an elevation of total 
bilirubin ≥2-fold ULN (measured in the same blood sample) and/or needs to be followed 
up according to the DILI checklist provided in the ISF
In addition to these criteria, the investigator may discontinue subjects at any time based on his 
or her clinical judgment.
Even if the trial treatment is discontinued, the subject remains in the trial and, given his/her 
agreement, will undergo the procedures for early treatment discontinuation and follow up as 
outlined in the Flow Chart and Section 6.2.3.
3.3.4.2
Withdrawal of consent to trial participation
Subjects may withdraw their consent to trial participation at any time without the need to
justify the decision. If a subject wants to withdraw consent, the investigator should be involved 
in the discussion with the subject and explain the difference between trial treatment 
discontinuation and withdrawal of consent to trial participation, as well as explain the options 
for continued follow up after trial treatment discontinuation, please see Section 3.3.4.1 above.
3.3.4.3
Discontinuation of the trial by the sponsor
Boehringer Ingelheim reserves the right to discontinue the trial at any time for any of the 
following reasons:

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 38 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
 
2. Failure to meet expected enrolment goals 
3. New toxicological findings, serious adverse events, or any safety information invalidating
the earlier positive benefit-risk-assessment. More specifically, the trial will be terminated if 
more than 50% of the subjects have drug-related and clinically relevant adverse events of 
moderate or severe intensity, or if at least 1 drug-related serious adverse event is reported
4. Violation of GCP, or the CTP, or the contract with BI impairing the appropriate conduct of 
the trial
Further reasons for termination of the trial:
5. If the judgement of the competent medical research ethics committee that has assessed the 
study is irrevocably revoked;
6. If a reasonable case can be made for terminating the study in the interests of the health of 
the research subjects;
7. If it transpires that continuation of the study cannot serve any scientific purpose, and this is 
confirmed by the medical research ethics committee that has issued a positive decision on 
the study;
8. If one of the parties or the funder has been declared insolvent or a bankruptcy/winding-up 
petition has been filed in respect of one of the parties or the financier, or one of the parties 
or the financier is dissolved as a legal entity;
9. If the principal investigator is no longer capable of performing the tasks of the principal 
investigator, and no replacement agreeable to both parties can be found;
10. If one of the two parties fails to comply with the obligations arising from the agreement 
and, provided compliance is not permanently impossible, this compliance has not taken 
place within thirty days of the defaulting party receiving a written request to comply, unless 
failure to comply is not in reasonable proportion to the premature termination of the study;
11. If circumstances beyond the control of the sponsor, investigator or funder make it 
unreasonable to require the study's continuation.
The investigator / trial site will be reimbursed for reasonable expenses incurred in case of trial 
termination (except if item 4 applies).
3.3.5
Replacement of subjects
In case one or more subjects do not complete the trial, the Trial Clinical Leader together with 
the Trial Pharmacokineticist and the Trial Statistician are to decide, if and how many subjects 
will be replaced. A replacement subject will be assigned a unique trial subject number, and will 
be assigned to the same treatment as the subject he or she replaces.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 39 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
4.
TREATMENTS
4.1
INVESTIGATIONAL TREATMENTS
 
4.1.1
Identity of the Investigational Medicinal Products
The characteristics of the test product are given below:

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 40 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
4.1.2
Selection of doses in the trial
 
 
 
 
.
4.1.3
Method of assigning subjects to treatment groups
Prior to screening visit, subjects will be contacted in writing and informed about the planned 
visit dates. The subjects willing to participate will be recruited to trial parts according to their 
temporal availability. Therefore, the allocation of subjects to dose groups is not influenced by 
trial personnel, but only by the subjects’ temporal availability. 
Subjects will be assigned to treatments (B, P, A, C, D) prior to drug administration. For this 
purpose, the randomisation list (for the randomized parts of the trial, i.e. part 1 and part 3) will 
be provided to the pharmacy and the trial site in advance. Numbers of the randomization list 
will be allocated to subjects on a first come first serve basis. Subjects are assigned to treatment 
according to the randomisation list in part 1 and part 3. In part 2 (non-randomized) all subjects 
receive treatment A. 
The randomization procedure is described in Section 7.6.
4.1.4
Drug assignment and administration of doses for each subject
The treatments are outlined in Table 4.1.4: 1 below.
 
DG= dose group
Administration of trial medication will be performed after subjects have fasted overnight; 
fasting is to start no less than 10 h before the scheduled dosing. The investigator (or authorised 
designee) will administer the trial medication as an oral dose together with about 240 mL of 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 41 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
water to subjects who are in a semi-recumbent position. For drug administration, the so-called 
four-eye principle (two-person rule) should be applied. For this, one authorised employee of 
the trial site should witness the administration of trial medication, and – if applicable – its 
preparation, if correct dosage cannot be ensured otherwise.
During the first 2 h after drug administration, subjects are not allowed to lie down (i.e. no 
declination of the upper body of more than 45 degrees from upright posture except for medical 
examination) or to sleep.
Subjects will be kept under close medical surveillance until 48 h after drug administration. 
4.1.5
Blinding and procedures for unblinding
Part 1 of this trial will be handled single-blind and Part 2 and Part 3 in an open fashion 
throughout (that is, during the conduct, including data cleaning and preparation of the 
analysis). This is considered acceptable because the potential for bias seems to be low and does 
not outweigh practical considerations.
Emergency envelopes will not be provided, because the trial is conducted single-blind in Part 1
and open-label in Parts 2 and 3, i.e. the investigator is aware of the treatment.
All trial data will be handled open label. This means that trial functions of the sponsor are 
unblinded (including CTL, clinical trial manager, data manager, statistician, bioanalyst, 
pharmacokineticist, pharmacometrician, drug metabolism scientist as well as dedicated 
personal of the trial site).
4.1.6
Packaging, labelling, and re-supply
The investigational medicinal products will be provided by BI. They will be packaged and 
labelled in accordance with local law and the principles of Good Manufacturing Practice. 
For details of packing and the description of the label, refer to the ISF.
The telephone number of the sponsor and the name, address and telephone number of the trial 
site are provided in the subject information form. The EudraCT number is indicated on the title 
page of this protocol as well as on the subject information and informed consent forms. 
Examples of the labels will be available in the ISF.
No re-supply is planned.
4.1.7
Storage conditions
Drug supplies will be kept in their original packaging and in a secure limited access storage 
area in accordance with the recommended (labelled) storage conditions. If necessary, a 
temperature log must be maintained to make certain that the drug supplies are stored at the 
correct temperature. If the storage conditions are found to be outside the specified range, the 
clinical trial manager (as provided in the list of contacts) is to be contacted immediately.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 42 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
4.1.8
Drug accountability
The investigator or designee (pharmacist at the
)
will receive the investigational drugs delivered from the sponsor following requirements are 
fulfilled:

Approval of the clinical trial protocol by the IRB / ethics committee

Availability of a signed and dated clinical trial contract between the sponsor and the 
investigational site

Approval/notification of the regulatory authority, e.g. competent authority

Availability of the curriculum vitae of the Principal Investigator

Availability of a signed and dated clinical trial protocol
Only authorised personnel documented in the form 'Delegation Log' may dispense medication 
to trial subjects. The trial medication must be administered in the manner specified in the CTP.
The investigator or designee must maintain records of the product’s delivery to the trial site, 
the inventory at the site, the use by each subject, and the disposal of unused products.These 
records will include dates, quantities, batch / serial numbers, expiry ('use-by') dates, and the 
unique code numbers assigned to the investigational medicinal product and trial subjects. The 
investigator or designee will maintain records that document adequately that the subjects were 
provided the doses specified by the CTP and reconcile all investigational medicinal products 
received from the sponsor. At the time of disposal of remaining trial medication, the 
investigator or designee must verify that no remaining supplies are in the investigator’s 
possession.
All unused medication will be disposed locally by the pharmacy of the
upon written 
authorisation of the clinical trial leader. Receipt, usage and disposal of trial medication must be 
documented on the appropriate forms. Account must be given for any discrepancies.
4.2
OTHER TREATMENTS, EMERGENCY PROCEDURES, RESTRICTIONS
4.2.1
Other treatments and emergency procedures
No additional treatment is planned. However, if adverse events require treatment, the 
investigator can authorise symptomatic therapy. In those cases, subjects will be treated as 
necessary and, if required, kept under supervision at the trial site or transferred to a hospital 
until all results of medical evaluations are acceptable.
For the treatment of post-spinal headache the application of an epidural blood patch may be 
applied at the discretion of the investigator.
Local anesthesia may be infiltrated subcutaneously for lumbar puncture and spinal catheter 
insertion.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 43 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
4.2.2
Restrictions
4.2.2.1
Restrictions regarding concomitant treatment
In principle, no concomitant therapy is allowed. All concomitant or rescue therapies will be 
recorded (including time of intake on study days) on the appropriate pages of the CRF.
Known inhibitors or inducers of CYP3A4 activity should be avoided during the entire study
due to drug-drug interaction potential with BI 474121.
Due to the spinal catheter placement, drugs that may negatively influence coagulation (e.g. 
acetylsalicylic acid due to the impact on platelet function) must not be administered starting 
from screening throughout the trial up to the end of trial visit. The minimum time between last 
dose of aspirin and lumbar puncture or spinal catheter insertion is 10 days for aspirin, low and 
high molecular weight heparins, 30 days for all other drugs with anticoagulatory effect.
Paracetamol may be used as analgesic drug if needed. 
4.2.2.2 Restrictions on diet and life style
While admitted to the trial site, the subjects will be instructed not to consume any foods or 
drinks other than those provided by the staff. Standardised meals will be served at the times
indicated in the Flow Chart. No food is allowed for at least 4 h after drug intake.
From 1 h before drug intake until lunch, fluid intake is restricted to the water administered with 
the drug, and an additional 240 mL of water at 2 h and 4 h post-dose (mandatory for all 
subjects). From lunch until 24 h post-dose, total fluid intake is restricted to 3000 mL. From 24 
h post-dose until discharge from trial site there are no restrictions regarding amount of fluid 
intake. 
Alcoholic beverages, grapefruits, Seville oranges (sour or bitter oranges) and their juices, and 
dietary supplements and products containing St. John's wort (Hypericum perforatum) are not 
permitted from 7 days before the first administration of trial medication until after the last PK 
sample is collected.
Methylxanthine-containing drinks or foods (such as coffee, tea, cola, energy drinks, or 
chocolate) are not allowed from 24 h before until 24 h after administration of trial medication.
Smoking is not allowed during in-house confinement while admitted to the trial site.
Excessive physical activity (such as competitive sport) should be avoided from 7 days before 
the administration of trial medication until the end of trial examination.
Direct exposure to the sun or exposure to solarium radiation should be avoided during the 
entire study.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 44 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
4.3
TREATMENT COMPLIANCE
Compliance will be assured by administration of all trial medication in the study centre under 
supervision of the investigating physician or a designee. The measured plasma concentrations 
of trial medication will provide additional confirmation of compliance.
Subjects who are non-compliant (for instance, who do not appear for scheduled visits or violate 
trial restrictions) may be removed from the trial and the CRF will be completed accordingly 
(for further procedures, please see Section 3.3.4.1).

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 45 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
5.
ASSESSMENTS
5.1
ASSESSMENT OF EFFICACY
Not applicable.
5.2
ASSESSMENT OF SAFETY
5.2.1
Medical examination
At screening, the medical examination will include demographics, height and body weight, 
smoking and alcohol history, relevant medical history and concomitant therapy, review of 
inclusion and exclusion criteria, review of vital signs (BP, PR), 12-lead ECG, laboratory tests, 
and a physical examination.
At screening or on day -1, prior to subjects’ inclusion in to the study, fundoscopy, using an 
ophtalmoscope, will be performed as part of the medical examination.
The medical examination is mandatory to exclude increased intracranial pressure or other 
clinically significant signs which would preclude spinal catheter placement.
On day -1 and on day 2-4, the medical examination also includes a symptom-directed physical 
examination.
On day 2-4, additionally a visual inspection of the lumbar puncture site is performed.
At the end of trial examination, the medical examination will include review of vital signs, 12-
lead ECG, laboratory tests, and a physical examination including inspection of the lumbar 
puncture site.
5.2.2
Vital signs
Automated oscillometric systolic and diastolic blood pressures and pulse rate will be measured 
using a Dash 3000, Dash 4000, Dynamap 400 or Dynamap ProCare 400 device at the times 
indicated in the Flow Chart, after subjects have rested for at least 5 min in a supine position. 
All recordings should be made using the same type of blood pressure recording instrument on 
the same arm, if possible.
5.2.3
Safety laboratory parameters
For the assessment of laboratory parameters, blood and urine samples will be collected by the 
trial site at the times indicated in the Flow Chart after the subjects have fasted for at least 10 h. 
For retests, at the discretion of the investigator or designee, overnight fasting is not required.
The parameters that will be determined are listed in Tables 5.2.3: 1 and 5.2.3: 2. Reference 
ranges will be provided in the ISF, section 10. 
Manual differential white blood cell count or urine sediment examinations will only be 
performed if there is an abnormality in the automatic blood cell count or in the urinalysis, 
respectively.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 46 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
Table 5.2.3: 1
Routine laboratory tests
Functional lab group
BI test name [comment/abbreviation]
A
B
C
Haematology
Haematocrit
Haemoglobin
Red Blood Cell Count/Erythrocytes 
White Blood Cells/Leucocytes
Platelet Count/Thrombocytes (quant)
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Automatic WBC 
differential, absolute
Neutrophils/Leukocytes; Eosinophils/Leukocytes; Basophils/ 
Leukocytes; Monocytes/Leukocytes; 
Lymphocytes/Leukocytes 
X
X
X
Manual differential 
WBC (if automatic
differential WBC is 
abnormal)
Neut. Poly (segs); Neut. Poly (segs), absol.; Neutrophils 
Bands; Neutrophils Bands, absol.; Eosinophils/Leukocytes; 
Eosinophils, absol.; Basophils/ Leukocytes; Basophils, absol.; 
Monocytes/ Leukocytes; Monocytes, absol.; 
Lymphocytes/Leukocytes; Lymphocytes, absol.
Coagulation
Activated Partial Thromboplastin Time 
Prothrombin time – INR (International Normalization Ratio)
Fibrinogen
X
X
X
X
X
X
--
--
--
Enzymes
AST [Aspartate transaminase] /GOT, SGOT 
ALT [Alanine transaminase] /GPT, SGPT
Alkaline Phosphatase
Gamma-Glutamyl Transferase 
Creatine Kinase [CK]
Troponin T 
LDH [Lactic dehydrogenase]
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Hormones
Thyroid Stimulating Hormone 
X
--
--
Substrates
Glucose (Plasma)
Creatinine 
eGFR (CKD-EPI)
Bilirubin, Total 
Bilirubin, Direct
Protein, Total
C-Reactive Protein (Quant)
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 47 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
Table 5.2.3: 1
Routine laboratory tests (cont.)
Functional lab group
BI test name [comment/abbreviation]
A
B
C
Electrolytes
Sodium
Potassium
X
X
X
X
X
X 
Urinalysis (Stix)
Urine Nitrite (qual)
Urine Protein (qual)
Urine Glucose (qual)
Urine Ketone (qual)
Urobilinogen (qual)
Urine Bilirubin (qual)
Urine RBC/Erythrocytes (qual)
Urine WBC/Leucocytes (qual)
Urine pH
X
X
X
X
X
X
X
X
X
--
--
--
--
--
--
--
--
--
X
X
X
X
X
X
X
X
X
Urine sediment 
(microscopic 
examination if 
erythrocytes, 
leukocytes nitrite or 
protein are abnormal 
in urine)
Only positive findings will be reported (for instance, the 
presence of sediment bacteria, casts in sediment, squamous 
epithelial cells, erythrocytes, leukocytes)
A: parameters to be determined at Visit 1 (screening examination) 
B: parameters to be determined at Visit 2 (for time points refer to Flow Chart)
C: parameters to be determined at Visit 3 (end of trial examination)
The tests listed in Table 5.2.3: 2 are exclusionary laboratory tests that may be repeated as 
required. The results will not be entered in the CRF/database and will not be reported in the 
CTR. It is planned to perform these tests during screening only. Drug screening will be 
performed at screening and at admission to the trial site as indicated in the Flow Chart.
Table 5.2.3: 2
Exclusionary laboratory tests
Functional lab group
Test name 
Drug screening (urine)
Amphetamine/MDA
Barbiturates
Benzodiazepine
Cannabis
Cocaine 
Methadone
Methamphetamines/MDMA/XTC
Opiates 
Phencyclidine
Tricyclic antidepressants
Infectious serology (blood)
Hepatitis B surface antigen (qualitative)
Hepatitis B core antibody (qualitative)
Hepatitis C antibodies (qualitative)
HIV-1 and HIV-2 antibody (qualitative)
To encourage compliance with alcoholic restrictions, a breath alcohol test (e.g. Alco-sensor 
VXL, 
) will be performed prior to each treatment period, and may 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 48 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
be repeated at any time during the study at the discretion of an investigator or designee. The 
results will not be included in the CTR.
SARS-COV-2 specific test will be conducted on day -1 and on day 2.
The laboratory tests listed in Tables 5.2.3: 1 and 5.2.3: 2 will be performed at the 
, with 
the exception of drug screening tests. These tests will be performed at the trial site using 
InstAlert™ Test 
 or 
comparable test systems.
Laboratory data will be transmitted electronically from the laboratory to the trial site.
5.2.4
Electrocardiogram
Twelve-lead ECGs (I, II, III, aVR, aVL, aVF, V1 - V6) will be recorded using a computerised 
electrocardiograph system Marquette 800/2000/5500 or Dash 3000 at the times provided in the 
Flow Chart.
To achieve a stable heart rate at rest and to assure high quality recordings, the site personnel 
will be instructed to assure a relaxed and quiet environment, so that all subjects are at complete 
rest.
All ECGs will be recorded for a 10 sec duration after subjects have rested for at least 5 min in a 
supine position. ECG assessment will always precede all other study procedures scheduled for 
the same time to avoid compromising ECG quality. 
All ECGs will be stored electronically on the Muse CV Cardiology System (
). Electrode placement will be performed according to the method 
of Wilson, Goldberger and Einthoven. 
All locally recorded ECGs will be evaluated by the investigator or a designee. 
The investigator will assess the ECG recording as 'normal', 'abnormal - not clinically 
significant', or 'abnormal - clinically significant' and include a description of the abnormality as 
required. The ECG parameters assessed will include heart rate, PR, QRS, QT, and QTcF 
(calculated using Fridericia's method).
Abnormal findings will be reported as AEs (during the trial) or baseline conditions (at 
screening) if assessed to be clinically relevant by the investigator. Any ECG abnormalities will 
be carefully monitored and, if necessary, the subject will be removed from the trial and will 
receive the appropriate medical treatment. 
ECGs may be repeated for quality reasons (for instance, due to alternating current artefacts, 
muscle movements, or electrode dislocation) and the repeated ECG will be used for analysis. 
Additional (unscheduled) ECGs may be collected by the investigator for safety reasons. 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 49 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
5.2.5
Assessment of adverse events
5.2.5.1
Definitions of adverse events
Adverse event
An adverse event (AE) is defined as any untoward medical occurrence in a patient or clinical 
investigation subject administered a medicinal product and which does not necessarily have to 
have a causal relationship with this treatment.
An AE can therefore be any unfavourable and unintended sign (including an abnormal 
laboratory finding), symptom, or disease temporally associated with the use of a medicinal 
product, whether or not considered related to the medicinal product.
The following should also be recorded as an AE in the CRF and BI SAE form (if applicable):

Worsening of pre-existing conditions 

Changes in vital signs, ECG, physical examination, and laboratory test results, if they 
are judged clinically relevant by the investigator
If such abnormalities already pre-exist prior to trial inclusion, they will be considered as 
baseline conditions and should be collected in the eCRF only.
Serious adverse event
A serious adverse event (SAE) is defined as any AE which fulfils at least one of the following 
criteria:

Results in death 

Is life-threatening, which refers to an event in which the patient was at risk of death at 
the time of the event; it does not refer to an event that hypothetically might have caused 
death if more severe 

Requires inpatient hospitalisation

Requires prolongation of existing hospitalisation

Results in persistent or significant disability or incapacity 

Is a congenital anomaly/birth defect 

Is deemed serious for any other reason if it is an important medical event when based 
upon appropriate medical judgment which may jeopardise the patient and may require 
medical or surgical intervention to prevent one of the other outcomes listed in the 
above definitions. Examples of such events are intensive treatment in an emergency 
room or at home for allergic bronchospasm, blood dyscrasias or convulsions that do 
not result in hospitalisation or development of dependency or abuse
AEs considered ‘Always Serious’
Cancers of new histology and exacerbations of existing cancer must be classified as a serious 
event regardless of the time since discontinuation of the trial medication and must be reported 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 50 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
as described in Section 5.2.5.2, subsections ‘AE Collection’ and ‘AE reporting to sponsor 
and timelines’.
In accordance with the European Medicines Agency initiative on Important Medical Events, 
Boehringer Ingelheim has set up a list of further AEs, which, by their nature, can always be 
considered to be ‘serious’ even though they may not have met the criteria of an SAE as defined 
above.
The latest list of ‘Always Serious AEs’ can be found in the eDC system, an electronic data 
capture system which allows the entry of trial data at the trial site. These events should always 
be reported as SAEs as described above.
Adverse events of special interest
The term adverse events of special interest (AESI) relates to any specific AE that has been 
identified at the project level as being of particular concern for prospective safety monitoring 
and safety assessment within this trial, e.g. the potential for AEs based on knowledge from 
other compounds in the same class. AESIs need to be reported to the sponsor’s 
Pharmacovigilance Department within the same timeframe that applies to SAEs, please see 
Section 5.2.5.2.2.
The following are considered as AESIs:

Hepatic injury
A hepatic injury is defined by the following alterations of hepatic laboratory 
parameters: 
o
An elevation of AST (aspartate transaminase) and/or ALT (alanine 
transaminase) ≥3-fold ULN combined with an elevation of total bilirubin 
≥2-fold ULN measured in the same blood sample, or
o
Aminotransferase (ALT, and/or AST) elevations ≥10 fold ULN
These lab findings constitute a hepatic injury alert and the subjects showing these lab 
abnormalities need to be followed up according to the ‘DILI checklist’ provided in the 
ISF and/or ECD. In case of clinical symptoms of hepatic injury (icterus, unexplained 
encephalopathy, unexplained coagulopathy, right upper quadrant abdominal pain, etc.) 
without lab results (ALT, AST, total bilirubin) available, the Investigator should make 
sure that these parameters are analysed, if necessary in an unscheduled blood test. 
Should the results meet the criteria of hepatic injury alert, the procedures described in 
the DILI checklist should be followed.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 51 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
Intensity (severity) of AEs
The intensity (severity) of the AE should be judged based on the following:
Mild:
Awareness of sign(s) or symptom(s) that is/are easily tolerated
Moderate:
Sufficient discomfort to cause interference with usual activity
Severe:
Incapacitating or causing inability to work or to perform usual activities
Causal relationship of AEs
Medical judgment should be used to determine the relationship, considering all relevant 
factors, including pattern of reaction, temporal relationship, de-challenge or re-challenge, 
confounding factors such as concomitant medication, concomitant diseases and relevant 
history.
Arguments that may suggest that there is a reasonable possibility of a causal relationship could 
be:

The event is consistent with the known pharmacology of the drug 

The event is known to be caused by or attributed to the drug class

A plausible time to onset of the event relative to the time of drug exposure

Evidence that the event is reproducible when the drug is re-introduced

No medically sound alternative aetiologies that could explain the event (e.g. pre-
existing or concomitant diseases, or co-medications)

The event is typically drug-related and infrequent in the general population not exposed 
to drugs (e.g. Stevens-Johnson syndrome)

An indication of dose-response (i.e. greater effect size if the dose is increased, smaller 
effect size if dose is reduced)
Arguments that may suggest that there is no reasonable possibility of a causal relationship 
could be:

No plausible time to onset of the event relative to the time of drug exposure is 
evident (e.g. pre-treatment cases, diagnosis of cancer or chronic disease within 
days / weeks of drug administration; an allergic reaction weeks after 
discontinuation of the drug concerned)

Continuation of the event despite the withdrawal of the medication, taking into 
account the pharmacological properties of the compound (e.g. after 5 half-lives). 
Of note, this criterion may not be applicable to events whose time course is 
prolonged despite removing the original trigger

Additional arguments amongst those stated before, like alternative explanation 
(e.g. situations where other drugs or underlying diseases appear to provide a 
more likely explanation for the observed event than the drug concerned)

Disappearance of the event even though the trial drug treatment continues or 
remains unchanged

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 52 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
5.2.5.2
Adverse event collection and reporting
AE collection
Upon enrolment into a trial, the subject’s baseline condition is assessed (for instance, by 
documentation of medical history/concomitant diagnoses), and relevant changes from baseline 
are noted subsequently. 
Subjects will be required to report spontaneously any AEs as well as the time of onset, end
time, and intensity of these events. In addition, each subject will be regularly assessed by the 
medical staff throughout the clinical trial and whenever the investigator deems necessary. As a 
minimum, subjects will be questioned for AEs (and concomitant therapies) at the time points 
indicated in the Flow Chart. Assessment will be made using non-specific questions such as 
‘How do you feel?’. Specific questions will be asked wherever necessary in order to more 
precisely describe an AE.
A carefully written record of all AEs shall be kept by the investigator in charge of the trial. 
Records of AEs shall include data on the time of onset, end time, intensity of the event, and 
any treatment or action required for the event and its outcome.
The following must be collected and documented on the appropriate CRF(s) by the 
investigator:

From signing the informed consent onwards until an individual subject’s end of trial: 
o
All AEs (serious and non-serious) and all AESIs 
o
The only exception to this rule are AEs (serious and non-serious) and AESIs in 
Phase I trials in healthy volunteers, when subjects discontinue from the trial due 
to screening failures prior to administration of any trial medication. In these 
cases, the subjects’ data must be collected at trial site but will not be entered in 
the CRF or trial database and will not be reported in the CTR.

After the individual subject’s end of trial: 
o
The investigator does not need to actively monitor the subject for AEs but 
should only report any occurrence of cancer and related SAEs and related 
AESIs of which the investigator may become aware of by any means of 
communication, e.g. phone call. Those AEs should, however, not be reported in 
the CRF.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 53 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
AE reporting to the sponsor and timelines
The Investigator must report SAEs, AESIs, and non-serious AEs which are relevant for the 
reported SAE or AESI, on the BI SAE form via fax immediately (within 24 hours) to the 
sponsor’s unique entry point (country specific contact details will be provided in the ISF). The 
same timeline applies if follow-up information becomes available. In specific occasions the 
Investigator could inform the sponsor upfront via telephone. This does not replace the 
requirement to complete and fax the BI SAE form. 
With receipt of any further information to these events, a follow-up SAE form has to be 
provided. For follow-up information, the same rules and timeline apply as for initial 
information.
Information required
All (S)AEs, including those persisting after the individual subject’s end of trial, must be 
followed up until they have resolved, have been sufficiently assessed as ‘chronic’ or ‘stable’, 
or no further information can be obtained.
Pregnancy
Once the male subject has been enrolled in the clinical trial and has taken trial medication, and 
if a partner of the male trial participant becomes pregnant, the investigator must report any 
drug exposure during pregnancy in a partner of the male trial participant immediately (within 
24 hours) by means of Part A of the Pregnancy Monitoring Form to the sponsor’s unique entry 
point, after a written consent of the pregnant partner.
The outcome of the pregnancy associated with the drug exposure during pregnancy must be 
followed up and reported to the sponsor’s unique entry point on the Pregnancy Monitoring 
Form for Clinical Trials (Part B).
The ISF will contain the Pregnancy Monitoring Form for Clinical Trials (Part A and Part B) as 
well as non-trial specific information and consent for the pregnant partner.
As pregnancy itself is not to be reported as an AE, in the absence of an accompanying SAE
and/or AESI, only the Pregnancy Monitoring Form for Clinical Trials and not the SAE form is 
to be completed. If there is an SAE and/or AESI associated with the pregnancy, an SAE form 
must be completed in addition.
5.3
DRUG CONCENTRATION MEASUREMENTS AND 
PHARMACOKINETICS
5.3.1
Assessment of pharmacokinetics
For the assessment of pharmacokinetics, blood and CSF samples will be collected at the time 
points indicated in the Flow Chart. The actual sampling times will be recorded and used for 
determination of pharmacokinetic parameters.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 54 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
5.3.2
Methods of sample collection
5.3.2.1
Blood sampling for pharmacokinetic analysis
For quantification of BI 474121 concentrations in plasma, about 2.7 mL of blood will be drawn 
from an antecubital or forearm vein into an K2-EDTA (dipotassium ethylenediaminetetraacetic 
acid)-anticoagulant blood drawing tube at the times indicated in the Flow Chart. Blood will be 
withdrawn by means of either an indwelling venous catheter or by venepuncture with a metal 
needle.
The EDTA-anticoagulated blood samples will be centrifuged for approximately 10 min at 
approximately 2000 x g to 4000 x g and at 4 to 8 °C. Two plasma aliquots will be obtained and 
stored in polypropylene tubes. The first aliquot should contain at least 0.5 mL of plasma. The 
process from blood collection until transfer of plasma aliquots into the freezer should be 
completed in less than 120 min. During this period, samples can be stored and handled at room 
temperature The time each aliquot was placed in the freezer will be documented. Until transfer 
on dry ice to the analytical laboratory, the aliquots will be stored upright at 
approximately -20°C or below at the trial site. The second aliquot will be transferred to the 
analytical laboratory after the bioanalyst has acknowledged safe arrival of the first aliquot. At 
the analytical laboratory, the plasma samples will be stored at approximately -20°C or below 
until analysis.
At a minimum, the sample tube labels should list
trial number, subject number, visit, 
and planned sampling time. 
After completion of the trial, the plasma samples may be used for further methodological 
investigations (e.g. for stability testing or assessment of metabolites). However, only data 
related to the analyte and/or its metabolite(s) including anti-drug antibodies (if applicable) will 
be generated by these additional investigations. The study samples will be discarded after 
completion of the additional investigations but not later than 5 years after the CTR is archived.
5.3.2.2
CSF sampling for pharmacokinetic analysis
Method for CSF sampling is described in Section 5.4.1 since the CSF samples are taken for PK 
and PD analyses.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 55 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
5.3.4
Pharmacokinetic - pharmacodynamic relationship
Exposure-effect relationship between BI 474121 (in plasma and CSF) and cGMP (in CSF) will 
be explored as feasible and appropriate.
In addition, plasma and CSF PK data, as well as CSF PD data, might be used for population 
PK/PD (PopPK/PD) analysis. If a formal PopPK/PD report is written, it will be as a separate 
report.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 56 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
5.4
ASSESSMENT OF BIOMARKERS
. 
CSF samples will be collected at the time points indicated in the Flow Chart. The actual 
sampling times will be recorded and used for determination of pharmacodynamic parameters.
5.4.1
Method and timing of sample collection 
Specimen Collection
CSF samplings will be done on the scheduled time points in a sterile manner. CSF will be
withdrawn using a 5 or 2 mL syringe under gentle aspiration.
Approximately 2 ml of CSF will be obtained at each time point scheduled in the Flow Chart.
At each sampling time point, the CSF is drawn in two separate syringes (syringe 1 and 2). 
The CSF sampling schedule with separation in aliquots, purpose and target lab are summarized 
in Table 5.4.1.1: 1
5.4.1.1
CSF sampling for pharmacokinetic and pharmacodynamic analysis
Table 5.4.1.1: 1 
CSF sampling scheme
Syringe Aliquot
Syringe
Volume 
Purpose
Lab
1
0
1
at least 0.3 mL up to 0.5 mL
amount of the CSF from the spinal 
catheter “dead space”. No CSF is 
discarded.
bioanalytics
2
1
2
at least 0.5 mL
PK
2
at least 0.5 mL
PK
3
at least 0.1 mL
PD
4
at least 0.1 mL
PD
5
at least 0.1 mL
PD
6
at least 0.1 mL
PD
7
at least 0.1 mL
PD
The process from CSF collection until transfer of CSF into aliquots into the freezer should be 
completed in less than 60 min. During this period, samples should be stored and handled on 
ice/ice bath.
Until transfer on dry ice to the analytical laboratory, the aliquots will be stored upright at 
approximately -70°C or below at the trial site. At the analytical laboratory, the CSF samples 
will be stored at approximately -70°C or below until analysis.
After completion of the study, leftover CSF samples may be used for further exploratory 
analyses such as identification/quantification of metabolites in CSF, methodological 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 57 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
investigations or exploration of other markers related to the treatment with BI 474121. Such 
further analyses would be conducted after completion of the study and will not be included in 
the clinical trial report.
All samples and leftovers will be discarded after completion of the additional investigations but 
not later than 5 years after the final study report has been signed.
5.5
BIOBANKING
Not applicable.
5.6
OTHER ASSESSMENTS
Not applicable.
5.7
APPROPRIATENESS OF MEASUREMENTS
All measurements performed during this trial are standard measurements and will be 
performed in order to monitor subjects’ safety and to determine pharmacokinetic and 
pharmacodynamic parameters in an appropriate way. The scheduled measurements will allow 
monitoring of changes in vital signs, standard laboratory values, and ECG parameters that 
might occur as a result of administration of trial medication. 
The safety assessments are standard, are accepted for evaluation of safety and tolerability of an 
orally administered drug, and are widely used in clinical trials. 
The pharmacokinetic parameters and measurements outlined in Section 5.3 are generally used 
assessments of drug exposure. 
The pharmacodynamic parameters and measurements are outlined in Sections 5.4. 
The pharmacodynamics measurements will employ validated methods and assays to allow 
exploring changes of cGMP level in CSF after exposure to BI 474121 as marker.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 58 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
6.
INVESTIGATIONAL PLAN
6.1
VISIT SCHEDULE
Exact times of measurements outside the permitted time windows will be documented. The 
acceptable time windows for screening and the end of trial examination are provided in the 
Flow Chart.
Study measurements and assessments scheduled to occur ‘before’ trial medication 
administration on Day 1 are to be performed and completed within a 3 h-period prior to the 
trial drug administration.
The acceptable deviation from the scheduled time for vital signs, ECG, and sample collection 
for laboratory tests will be ± 30 min.
If scheduled in the Flow Chart at the same time as a meal, blood sampling, vital signs, and 12-
lead ECG recordings have to be done first. Furthermore, if several measurements including 
venepuncture are scheduled for the same time, venepuncture should be the last of the 
measurements due to its inconvenience to the subject and possible influence on physiological
parameters. For the same reason, spinal cathether placement as invasive procedure should be 
done after ECG or vital signs measurements.
For planned blood sampling times, refer to the Flow Chart. While these nominal times should 
be adhered to as closely as possible, the actual sampling times will be recorded and used for 
the determination of pharmacokinetic and pharmacodynamics parameters.
If a subject misses an appointment, it will be rescheduled if possible. The relevance of 
measurements outside the permitted time windows will be assessed no later than at the Report 
Planning Meeting.
6.2
DETAILS OF TRIAL PROCEDURES AT SELECTED VISITS
6.2.1
Screening period
After having been informed about the trial, all subjects will provide written informed consent 
in accordance with GCP and local legislation prior to enrolment in the study.
For information regarding laboratory tests (including drug and virus screening), ECG, vital 
signs, and medical examination, refer to Sections 5.2.3 to 5.2.5.
6.2.2
Treatment period
Subjects will be admitted to the trial site on day -1. For activities on day -1 to day 4, see 
Flow Chart.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 59 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
Spinal catheter for CSF sampling
On day 1, prior to drug administration, the spinal catheter is inserted.
The spinal catheterisation procedure, as well as CSF sampling and removal of catheter follows 
medical standards with appropriate safety measures as laid down in the 
 SOP on 
continuous CSF sampling using a spinal catheter [c34094265].
For syringes used and volumes drawn see Section 5.4.1 of the CTP. In this respect, the
SOP does not apply.
Safety measurements
The safety measurements performed during the treatment period are specified in Section 5.2 of 
this protocol and in the Flow Chart. For details on times of all other trial procedures, refer to 
the Flow Chart. AEs and concomitant therapy will be assessed continuously from screening 
until the end of trial examination.
6.2.3
Follow-up period and trial completion
For AE assessment, laboratory tests, recording of ECG and vital signs, and medical
examination during the follow-up period, see Sections 5.2.1 to 5.2.5.
Subjects who discontinue treatment before the end of the planned treatment period should 
undergo the EoTrial Visit.
All abnormal values (including laboratory parameters) that are assessed as clinically relevant 
by the investigator will be monitored using the appropriate tests until a return to a medically 
acceptable level is achieved. (S)AEs persisting after a subject’s EoTrial Visit must be followed 
until they have resolved, have been sufficiently characterised, or no further information can be 
obtained. 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 60 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
7.
STATISTICAL METHODS AND DETERMINATION OF
SAMPLE SIZE
7.1
STATISTICAL DESIGN – MODEL
Due to the exploratory nature of this trial, there is no primary objective in a confirmatory 
sense. The primary endpoints (see Section 2.1.2) of this trial will be assessed by ANCOVA 
models.
 
The assessment of safety and tolerability is a further objective of this trial, and will be 
evaluated by descriptive statistics for the parameters specified in Section 2.2.2.2.
7.2
NULL AND ALTERNATIVE HYPOTHESES
It is not planned to test any statistical hypotheses in this study.
Any confidence intervals computed are to be interpreted in the perspective of the exploratory 
character of the study; i.e., confidence intervals are considered as interval estimates for effects.
7.3
PLANNED ANALYSES
7.3.1
General considerations
Statistical analyses will be based on the following analysis sets:

Treated set (TS):
The treated set includes all subjects who were randomized and treated with at least one 
dose of study drug (i.e. verum or placebo). The treated set will be used for safety 
analyses
Pharmacokinetic parameter analysis set (PKS):
This set includes all subjects in the treated set (TS) who provide at least one PK 
endpoint that was defined as primary or secondary and was not excluded due to a 
protocol deviation relevant to the evaluation of PK or due to PK non-evaluability (as 
specified in the following subsection ‘Pharmacokinetics’). Thus, a subject will be 
included in the PKS, even if he/she contributes only one PK parameter value to the 
statistical assessment. Descriptive and model based analysis of PK parameters will be 
based on the PKS
Pharmacodynamic parameter analysis set (PDS):
This set includes all evaluable subjects from the TS who provide at least one evaluable 
pre- and post-dose measure for a PD endpoint. Descriptive and model based analysis of 
the PD endpoints will be based on the PDS

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 61 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
All individual data will be listed.
Adherence to the protocol will be assessed by the trial team. Important protocol deviation 
(IPD) categories will be specified in the iPD specification file prior to trial initiation, IPDs will 
be identified no later than in the Report Planning Meeting, and the IPD categories will be 
updated as needed.
Pharmacokinetics
The pharmacokinetic parameters listed in Section 2.1 and 2.2 for drug BI 474121 will be 
calculated according to the relevant BI internal procedures. 
Plasma and CSF concentration data and parameters of a subject will be included in the 
statistical pharmacokinetic (PK) analyses if they are not flagged for exclusion due to a protocol 
deviation relevant to the evaluation of PK (to be decided no later than in the Report Planning 
Meeting) or due to PK non-evaluability (as revealed during data analysis, based on the criteria 
specified below). Exclusion of a subject’s data will be documented in the CTR.
Relevant protocol deviations may be

Incorrect trial medication taken, i.e. the subject received at least one dose of trial
medication the subject was not assigned to

Incorrect dose of trial medication taken

Use of restricted medications
Plasma and CSF concentrations and/or parameters of a subject will be considered as non-
evaluable, if for example

The subject experienced emesis that occurred at or before two times median tmax of the 
respective treatment (Median tmax is to be determined excluding the subjects 
experiencing emesis)

Missing samples/concentration data at important phases of PK disposition curve
Plasma and CSF concentration data and parameters of a subject which is flagged for exclusion 
will be reported with its individual values but will not be included in the statistical analyses. 
Descriptive and inferential statistics of PK parameters will be based on the PKS.
Only concentration values within the validated concentration range and actual sampling times 
will be used for the calculation of pharmacokinetic parameters. Concentrations used in the 
pharmacokinetic calculations will be in the same format provided in the bioanalytical report, 
(that is, to the same number of decimal places provided in the bioanalytical report). 
Biomarkers
The pharmacodynamic parameters listed in Section 2.1 and 2.2 for cGMP will be calculated 
according to the relevant BI internal procedures. 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 62 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
7.3.2
Primary endpoint analyses
Maximum exposure-related change from baseline of cGMP in CSF
The maximum exposure-related change from baseline in cGMP in CSF will be explored using 
an ANCOVA model, which can be described by the following equation:
yi,j = α ln(cGMPbase,i) + treatmentj + ei,j,
Where
yi,j
= natural logarithm of the ratio cGMPmax,i/cGMPbase,i for subject i receiving 
treatment j
α
= slope parameter for the baseline effect
cGMPbase,i = cGMPbase for subject i
treatmentj = the jth treatment effect, (placebo, 2.5mg, 10mg, 20 mg, 40mg)
ei,j
= random error associated with ith subject who received treatment j 
For the endpoint cGMPmax/cGMPbase, the difference between the expected means for ln(T) –
ln(R) will be estimated by the difference in the corresponding least square means (point 
estimate) and two-sided 90% confidence intervals based on the t-distribution will be computed. 
These quantities will then be back-transformed to the original scale to give the point estimator 
and interval estimates.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 63 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
Estimates will be computed for the different dose groups (T) versus placebo (R), respectively.
Final analysis will include data from all dose groups.
Cmax ratio of BI 474121 in CSF compared to plasma 
The relationship between exposures of BI 474121 in CSF compared to plasma will be
explored using an ANOVA model, which can be described by the following equation:
ln(Cmaxi,j,k) = pkmatrixk + treatmentj + ei,j,k
where
pkmatrixk = kth substance effect, (CSF or plasma)
treatmentj = the jth treatment effect, (2.5mg, 10mg, 20 mg, 40mg)
ei,j,k
= random error associated with ith subject who received treatment j in 
substance k
All effects will be considered as fixed. Estimates will be provided by treatment as well as 
overall.
The pharmacokinetic parameter Cmax will be log transformed (natural logarithm) prior to fitting 
the ANOVA model. The difference between the expected means for ln(Cmax in CSF)-ln(Cmax in 
plasma) will be estimated by the difference in the corresponding least square means (point 
estimate) and two-sided 90% confidence intervals based on the t-distribution will be computed. 
These quantities will then be back-transformed to the original scale to give the point estimator 
and interval estimates for the geometric mean of the ratio between exposure in CSF and 
exposure in plasma. Estimates will computed separately for each treatment.
Additionally, the primary endpoints will be analysed using descriptive statistics.
7.3.3
Secondary endpoint analyses
The secondary endpoints (refer to Section 2.1.3) will be analysed using descriptive statistics.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 64 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
7.3.5
Safety analyses
Safety will be analysed based on the assessments described in Section 2.2.2.2. All treated 
subjects (TS, refer to Section 7.3) will be included in the safety analysis. Safety analyses will 
be descriptive in nature and based on BI standards. No hypothesis testing is planned.
For all analyses, the treatment actually administered (= treatment at onset) to the subject will 
be used (any deviations from the randomised treatment will be discussed in the minutes of the 
Report Planning Meeting).
Treatments will be compared in a descriptive way. Tabulations of frequencies/proportions will 
be used to evaluate categorical (qualitative) data, and tabulations of descriptive statistics will 
be used to analyse continuous (quantitative) data.
Measurements (such as vital signs, or laboratory parameters) or AEs will be assigned to 
treatments (see Section 4.1) based on the actual treatment at the planned time of the 
measurement or on the recorded time of AE onset (concept of treatment emergent AEs). 
Therefore, measurements planned or AEs recorded prior to first intake of trial medication will 
be assigned to the screening period, those between first trial medication intake and end of REP 
(see Section 1.2.2) will be assigned to the treatment period. Events occurring after the REP but 
prior to end of trial termination date will be assigned to ’follow-up’. These assignments 
including the corresponding time intervals will be defined in detail in the TSAP. Note that AEs 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 65 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
occurring after the last per protocol contact but entered before final database lock will be 
reported to Pharmacovigilance only and will not be captured in the trial database.
Additionally, further treatment intervals (analysing treatments) may be defined in the TSAP in 
order to provide summary statistics for time intervals, on-treatment totals, or periods without 
treatment effects (such as screening and follow-up intervals).
Adverse events will be coded using the Medical Dictionary for Regulatory Activities 
(MedDRA). Frequency, severity, and causal relationship of AEs will be tabulated by treatment,
system organ class, and preferred term. SAEs, AESIs (see Section 5.2.5.1), and other 
significant AEs (according to ICH E3) will be listed separately.
Previous and concomitant therapies will be presented per treatment group without 
consideration of time intervals and treatment periods.
Laboratory data will be compared to their reference ranges. Values outside the reference range 
as well as values defined as possibly clinically significant will be highlighted in the listings. 
Additionally, differences from baseline will be evaluated.
Vital signs or other safety-relevant data will be assessed with regard to possible on-treatment 
changes from baseline.
Relevant ECG findings will be reported as AEs.
7.4
INTERIM ANALYSIS
No formal interim analyses is planned.
However, a preliminary analysis of PK and PD parameters in CSF and plasma (including Cmax
and AUC0-24 for BI 474121 in plasma) provided as individual values and gMeans per dose 
level, will be performed after Part 1 and Part 2 (if applicable). These preliminary analyses will 
additionally comprise analyses of safety parameters.
In contrast to the final PK and PD calculations, the preliminary analysis will be based on 
planned sampling times rather than on actual times. Therefore, minor deviations of preliminary 
and final results may occur. The preliminary results will be distributed to the investigator and 
the trial team.
Depending on the results of available preliminary PK analyses, the tolerability and safety of the 
compound, additional PK preliminary analysis may be performed based on the request of the 
Clinical Trial Leader, the investigator, or Trial Clinical Pharmacokineticist. No formal 
preliminary PK and PD report will be written.
In addition, after Part 1 and Part 2 (if applicable) the ANCOVA model for evaluation of 
maximum exposure-related changes in cGMP as described in Section 7.3.1 will be computed. 
After trial Part 1 the data (treatment B and placebo) will be analysed, after trial Part 2 the data 
from treatment A and placebo (from part 1) will be analysed.
If the placebo adjusted change in cGMPmax is not considered sufficient, the sponsor reserves 
the right to terminate the trial.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 66 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
7.5
HANDLING OF MISSING DATA
7.5.1
Safety
It is not planned to impute missing values for safety parameters.
7.5.2
Pharmacokinetics
Handling of missing PK data will be performed according to the relevant BI internal 
procedures.
PK parameters that cannot be reasonably calculated based on the available drug concentration-
time data will not be imputed.
7.5.3
Pharmacodynamics
It is not planned to impute missing values for safety parameters.
7.6
RANDOMISATION
In Part 1 subjects will be randomised to the two treatments in a 3:2 ratio, which reflects the 
ratio of subjects receiving active drug to placebo. In Part 2 all subjects will receive active 
treatment. In Part 3 subjects will be randomised to the two treatment groups in a 1:1 ratio.
The sponsor will arrange for the randomisation as well as packaging and labelling of study 
medication. The randomisation lists will be generated using a validated system, which involves 
a pseudo-random number generator and a supplied seed number so that the resulting allocation 
of medication numbers to treatment is both reproducible and non-predictable.
The randomisation lists will contain mirror sets for part 1 and part 3 to allow for subject 
replacement (refer to Section 3.3.5).
7.7
DETERMINATION OF SAMPLE SIZE
It is planned to include a total of 24 subjects in this trial. The planned sample size is not based 
on a power calculation. The size of 4 subjects for dose group 3 and 4 (all on active treatment) 
is commonly used in studies of the present type and is in general considered as sufficient for 
the exploratory evaluation of single dose safety, pharmacokinetics, and pharmacodynamics.
The data of study Part 1 and 2 is used to decide on the further conduct of the trial. Therefore, in 
this part the sample size has been increased to 12 active subjects and 4 control subjects, to 
reduce the risk for missing data (see Section 3.1). 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 67 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
8.
INFORMED CONSENT, TRIAL RECORDS, DATA 
PROTECTION, PUBLICATION POLICY, AND
ADMINISTRATIVE STRUCTURE
The trial will be carried out in compliance with the protocol, the ethical principles laid down in 
the Declaration of Helsinki, in accordance with the ICH Harmonized Guideline for Good 
Clinical Practice (GCP), relevant BI Standard Operating Procedures (SOPs), the EU regulation 
536/2014, and other relevant regulations. Investigators and site staff must adhere to these 
principles.
Standard medical care (prophylactic, diagnostic, and therapeutic procedures) remains the 
responsibility of the subject’s treating physician.
The investigator will inform the sponsor immediately of any urgent safety measures taken to 
protect the trial subjects against any immediate hazard, as well as of any serious breaches of 
the protocol or of ICH GCP.
The Boehringer Ingelheim transparency and publication policy can be found on the following 
web page: trials.boehringer-ingelheim.com. The rights of the investigator and of the sponsor 
with regard to publication of the results of this trial are described in the investigator contract. 
As a general rule, no trial results should be published prior to archiving of the CTR.
The terms and conditions of the insurance coverage are made available to the investigator and 
the subjects, and are stored in the ISF.
8.1
TRIAL APPROVAL, SUBJECT INFORMATION, INFORMED CONSENT
This trial will be initiated only after all required legal documentation has been reviewed and 
approved by the respective Institutional Review Board (IRB) / Independent Ethics Committee 
(IEC) and competent authority (CA) according to national and international regulations. The 
same applies for the implementation of changes introduced by amendments.
Prior to a subject’s participation in the trial, written informed consent must be obtained from 
each subject (or the subject’s legally accepted representative) according to ICH-GCP and to the 
regulatory and legal requirements of the participating country. Each signature must be 
personally dated by each signatory and the informed consent and any additional subject-
information form retained by the investigator as part of the trial records. A signed copy of the 
informed consent and any additional subject information must be given to each subject or the 
subject’s legally accepted representative.
The subject must be given sufficient time to consider participation in the trial. The investigator 
or delegate obtains written consent of the subject’s own free will with the informed consent 
form after confirming that the subject understands the contents. The investigator or
 delegate 
must sign (or place a seal on) and date the informed consent form. If a trial collaborator has 
given a supplementary explanation, the trial collaborator also signs (or places a seal on) and 
dates the informed consent. For subjects enrolled during the COVID-19 pandemic: In addition 
to the study specific informed consent, separate written consent will be obtained for testing on 
SARS-CoV-2 infection.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 68 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
Re-consenting may become necessary when new relevant information becomes available and 
should be conducted according to the sponsor’s instructions.
The consent and re-consenting process should be properly documented in the source 
documentation.
8.2
DATA QUALITY ASSURANCE
A risk-based approach is used for trial quality management. It is initiated by the assessment of 
critical data and processes for trial subject protection and reliability of the results as well as 
identification and assessment of associated risks. An Integrated Quality and Risk Management 
Plan documents the rationale and strategies for risk management during trial conduct including 
monitoring approaches, vendor management and other processes focusing on areas of greatest 
risk. 
Continuous risk review and assessment may lead to adjustments in trial conduct, trial design or 
monitoring approaches. 
A quality assurance audit/inspection of this trial may be conducted by the sponsor, sponsor’s 
designees, or by IRB / IEC or by regulatory authorities. The quality assurance auditor will have 
access to all medical records, the investigator’s trial-related files and correspondence, and the 
informed consent documentation of this clinical trial.
8.3
RECORDS
CRFs for individual subjects will be provided by the sponsor. For drug accountability, refer to 
Section 4.1.8.
8.3.1
Source documents
In accordance with regulatory requirements, the investigator should prepare and maintain 
adequate and accurate source documents and trial records for each trial subject that include all 
observations and other data pertinent to the investigation. Source data as well as reported data 
should follow the ‘ALCOA principles’ and be attributable, legible, contemporaneous, original, 
and accurate. Changes to the data should be traceable (audit trail).
Data reported on the CRF must be consistent with the source data or the discrepancies must be 
explained.
Before providing any copy of subjects’ source documents to the sponsor, the investigator must 
ensure that all subject identifiers (e.g., subject’s name, initials, address, phone number, and 
social security number) have properly been removed or redacted to ensure subject 
confidentiality.
If the subject is not compliant with the protocol, any corrective action (e.g. re-training) must be 
documented in the subject file.
For the CRF, data must be derived from source documents, for example:

Subject identification: sex, year of birth (in accordance with local laws and regulations)

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 69 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018

Subject participation in the trial (substance, trial number, subject number, date subject 
was informed)

Dates of subject’s visits, including dispensing of trial medication

Medical history (including trial indication and concomitant diseases, if applicable)

Medication history

AEs and outcome events (onset date [mandatory], and end date [if available])

SAEs (onset date [mandatory], and end date [if available])

Concomitant therapy (start date, changes)

Originals or copies of laboratory results and other imaging or testing results, with 
proper documented medical evaluation (in validated electronic format, if available)

ECG results (original or copies of printouts)

Fundoscopy results

Completion of subject’s participation in the trial (end date; in case of premature 
discontinuation, document the reason for it, if known)

Prior to allocation of a subject to a treatment into a clinical trial, there must be 
documented evidence in the source data (e.g. medical records) that the trial participant 
meets all inclusion criteria and does not meet any exclusion criteria. The absence of 
records (either medical records, verbal documented feedback of the subject or testing 
conducted specific for a protocol) to support inclusion/exclusion criteria does not make 
the subject eligible for the clinical trial.

Volunteer Inclusion Period check documentation
8.3.2
Direct access to source data and documents
The investigator /institution will allow site trial-related monitoring, audits, IRB / IEC review 
and regulatory inspections. Direct access must be provided to the CRF and all source 
documents/data, including progress notes, copies of laboratory and medical test results, which 
must be available at all times for review by the Clinical Research Associate, auditor and 
regulatory inspector (e.g. FDA). They may review all CRFs and informed consents. The 
accuracy of the data will be verified by direct comparison with the source documents described 
in Section 8.3.1. The sponsor will also monitor compliance with the protocol and GCP.
8.3.3
Storage period of records
Trial site:
The trial site must retain the source and essential documents (including ISF) according to 
contract or the local requirements valid at the time of the end of the trial (whatever is longer).
Sponsor:
The sponsor must retain the essential documents according to the sponsor’s SOPs.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 70 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
8.4
EXPEDITED REPORTING OF ADVERSE EVENTS
BI is responsible to fulfil their legal and regulatory reporting obligation in accordance with 
regulatory requirements.
8.5
STATEMENT OF CONFIDENTIALITY AND SUBJECT PRIVACY
Individual subject data obtained as a result of this trial is considered confidential and disclosure 
to third parties is prohibited with the exceptions noted in Section 8.7. 
Data protection and data security measures are implemented for the collection, storage and 
processing of patient data in accordance with the principles 6 and 12 of the WHO GCP 
handbook.
Personalised treatment data may be given to the subject’s personal physician or to other 
appropriate medical personnel responsible for the subject’s welfare. Data generated at the site 
as a result of the trial need to be available for inspection on request by the participating 
physicians, the sponsor’s representatives, by the IRB / IEC and the regulatory authorities.
8.5.1
Collection, storage and future use of biological samples and corresponding 
data
Measures are in place to comply with the applicable rules for the collection, storage, and future 
use of biological samples and clinical data, in particular

Sample and data usage has to be in accordance with the informed consent

The BI-internal or external facilities storing biological samples from clinical trial
participants are qualified for the storage of biological samples collected in clinical 
trials.

An appropriate sample and data management system, incl. audit trail for clinical data 
and samples to identify and destroy such samples according to the informed consent 
form (ICF) is in place

A fit for the purpose documentation ensures compliant usage

A fit for purpose approach will be used for assay/equipment validation depending on 
the intended use of the biomarker data
Samples and/or data may be transferred to third parties and other countries as specified in the 
ICF.
8.6
TRIAL MILESTONES
The start of the trial is defined as the date of the enrolment of the first subject in the trial.
The end of the trial is defined as the ‘date of the last visit of the last subject in whole trial’ 
(‘Last Subject Completed’) or ‘end date of the last open AE’ or ‘date of the last follow-up test’ 
or ‘date of an AE has been decided as sufficiently followed-up’, whichever is latest.
Early termination of the trial is defined as the premature termination of the trial for any 
reason before the end of the trial as specified in this protocol.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 71 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
Temporary halt of the trial is defined as any unplanned interruption of the trial by the 
sponsor with the intention to resume it.
Suspension of the trial is defined as an interruption of the trial based on a Health Authority 
request.
The EC/competent authority in each participating EU member state will be notified about the 
trial milestones according to the laws of each member state. 
A final report of the clinical trial data will be written only after all subjects have completed the 
trial in all countries (EU or non-EU), so that all data can be incorporated and considered in the 
report.
8.7
ADMINISTRATIVE STRUCTURE OF THE TRIAL
The trial is sponsored by Boehringer Ingelheim (BI).
The trial will be conducted at
 under the supervision of the 
Principal Investigator. Relevant documentation on the participating (Principal) Investigators 
(e.g. their curricula vitae) will be filed in the ISF.
BI has appointed a Clinical Trial Leader, responsible for coordinating all required trial 
activities, in order to 

Manage the trial in accordance with applicable regulations and internal SOPs

Direct the clinical trial team in the preparation, conduct, and reporting of the trial

ensure appropriate training and information of clinical trial managers (CTMs), Clinical
Research Associates, and investigators of participating trial sites
The trial medication will be provided by the 
 
.
Safety laboratory tests will be performed by the local laboratory of the trial site.
Analyses of BI 474121 concentrations in plasma and CSF will be performed at 
 
.
Analyses of cGMP in CSF will be performed at 
 
On-site monitoring will be performed by BI or a contract research organisation appointed by 
BI.
Data management and statistical evaluation will be done by BI or a contract research 
organisation appointed by BI according to BI SOPs.
Tasks and functions assigned in order to organise, manage, and evaluate the trial are defined 
according to BI SOPs. A list of responsible persons and relevant local information can be 
found in the ISF.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 72 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
9.
REFERENCES 
9.1
PUBLISHED REFERENCES
R10-5092
Cooke SF, Bliss TVP. Plasticity in the human central nervous system. Brain 
2006. 129: 1659-1673
R10-5102
Reymann KG, Frey JU. The late maintenance of hippocampal LTP: 
requirements, phases, 'synaptic tagging', 'late-associativity' and implications.
Neuropharmacology 52, 24 - 40 (2007)
R13-4518
Hu NW, Ondrejcak T, Rowan MJ. Glutamate receptors in preclinical 
research on Alzheimer's disease: update on recent advances. Pharmacol 
Biochem Behav 100, 855 - 862 (2012)
R13-4521
Lin CH, Lane HY, Tsai GE. Glutamate signaling in the pathophysiology and 
therapy of schizophrenia. Pharmacol Biochem Behav 100, 665 - 677 (2012)
R20-0666
Daas I den, Wemer J, Farha KA, Tamminga W, Boer T de, Spanjersberg R, 
et al. Serial CSF sampling over a period of 30 h via an indwelling spinal 
catheter in healthy volunteers: headache, back pain, tolerability and measured 
acetylcholine profile. Eur J Clin Pharmacol 2013; 69: 1083-1090.
R20-2943
Cavens L, Ramael S. Cerebrospinal fluid sampling in phase 1 clinical trials: 
mind over matter?
website.sgs.co.mz/~/media/Global/Documents/Technical%20Documents/SG
S-Clinica l-Cerebrospinal-Fluid-EN-09.pdf (access date: 11 September 2020) 
; SGS Life Science
9.2
UNPUBLISHED REFERENCES
c26859058
BI 474121 - Investigator’s Brochure, Current Version
c33667635
Snapshot analysis – 1411-0001 safety data as of 18-Sep-2020 
c33854225
2020-09-16-ecg-report-dg-1-7-fig. 08 Oct 2020.
c33854226
2020-09-16-ecg-reports-dg-1-7-tbl. 08 Oct 2020.
c33854260
2020-09-16-ecg-report-dg-1-7-tbl. 08 Oct 2020.
c34094265
SOP “Continous cerebrospinal fluid sampling using a spinal 
catheter”, current version
c34094272
procedures and measures during the COVID-19 pandemic, current 
version
n00265648
 
. 18B128. BI 474121: 4-week 
oral (gavage) toxicity study in rats
n00269861
 In vitro inhibition of human, rat and monkey 
recombinant phosphodiesterase (PDE) 2A and human recombinant PDE1a, 
1b and 1c by BI 47412. 05 June 2019

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 73 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
n00271367
GM20LK. BI 474121. Toxicity Study by Oral Gavage 
Administration to Cynomolgus Monkeys for 4 Weeks Followed by a 4 Week 
Recovery Period

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 74 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
10.
APPENDICES
10.1
COVID-19 RISK ASSESSMENT AND MITIGATION STRATEGIES
The current SARS-CoV-2 pandemic can pose a challenge to integrity of the trials, protection of 
participants’ rights, safety and wellbeing and the safety of clinical trial staff. Therefore, risk 
mitigation strategies will be put in place for this trial following the Central Committee on 
Research Involving Human Subjects (CCMO) guidance Recommendations for the conduct of 
clinical research at the time of restrictive measures due to the coronavirus. These mitigation 
strategies will be kept in place and evaluated on an ongoing basis for the duration of this trial, 
or until there is a consensus that the period of the SARS-CoV-2 outbreak in the Netherlands 
has passed. If the dynamics of the SARS-CoV-2 outbreak change in such a way that the safety 
of the trial participants and clinical trial staff or integrity of the data collected during this 
clinical trial cannot be guaranteed the trial will be halted.
10.1.1
COVID-19 RISK ASSESSMENT
Risk for Trial Participants and Trial Staff
Healthy subjects in the current study fall in a low risk category for complications of COVID-
19, the disease caused by the SARS-CoV-2 virus. To prevent SARS-CoV-2 infections among 
trial participants, measures and procedures based on the advice issued by the D
 
) and COVID-19 measures declared by the Dutch 
government will be adhered to as outlined in 
SOP
procedures and measures 
during the COVID-19 pandemic” [c34094272]. Site trial staff in direct contact and/or within 
1.5 m distance of study subjects will receive additional protection via the use of Personal 
Protective Equipment (PPE). All trial subjects will be screened for SARS-CoV-2 with a PCR: 
1) prior to the/each admission at the clinical unit with at least one overnight stay, and; 2) in 
case of symptoms possibly related to COVID-19. Healthy subjects/patients will be excluded 
from the study when tested positive for SARS-CoV-2.
Protection of Trial Integrity
Adherence to the protocol and
SOP [c34094272] protects the integrity of the data 
collected during this clinical trial, as well as participants’ data protection rights. 
Impact of Investigational Drug on COVID-19 disease
Based on the mechanism of action of the investigational drug and the available information in 
the Investigators Brochure, there is currently no reason to believe that the investigational drug 
could 1) increase the susceptibility of trial participants to the SARS-CoV-2 virus, or 2) worsen 
or mask any COVID-19 signs, symptoms or complications.
COVID-19 Contingency Plan 
Any subject that presents with COVID-19-related symptoms and/or has a positive SARS-CoV-
2 PCR will be excluded from (further) participation in the trial and will receive follow-up
medical attention per 
 SOP, see [c34094272].

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 75 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
10.1.2
COVID-19 RISK MITIGATION MEASURES
SARS-CoV-2 Screening
Upon admission to the clinical research unit in the morning of day -1 and on day 2, a 
nasopharyngeal and throat swab will be taken to test for SARS-CoV-2 infection. Subjects will 
be required to fast for at least 1 hour prior to the nasopharyngeal and throat swab. Samples will 
be sent to NMDL-LCPL lab for qPCR analysis. Only subjects with a negative SARS-CoV-2 
qPCR analysis prior to first dosing will be included in the study. 
Subjects that test positive for a SARS-CoV-2 infection prior to the first dose will be withdrawn 
from the study and may be replaced. Subjects that test positive for a SARS-CoV-2 infection 
after the first study dose will be withdrawn from the study and may be replaced. Subjects with 
a SARS-CoV-2 infection will be followed-up according to SOP [c34094272].
COVID-19 Arrival Checklist and Temperature Measurement
Trial participants are requested to come to the clinic only if they have no symptoms that could 
indicate a COVID-19 infection and if they have not been in contact with a COVID-19 patient 
according to 
) guidelines. A standard 
checklist and temperature measurement are used upon arrival at the clinic.
COVID-19 Lifestyle Restrictions
Trial participants will be required to adhere to the measures and procedures outlined in
SOP [c34094272], based on the advice issued by the
 and COVID-19 measures declared 
by the Dutch government, to prevent SARS-CoV-2 infections among trial participants and 
clinical site staff.

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 76 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
11.
DESCRIPTION OF GLOBAL AMENDMENTS
11.1
GLOBAL AMENDMENT 1
Date of amendment
10-Dec-2020
EudraCT number
EU number
2020-002321-28
BI Trial number
1411-0013
BI Investigational Medicinal 
Product(s)
BI 474121
Title of protocol
Pharmacokinetics and pharmacodynamic effects of 
different single oral doses of BI 474121 in healthy 
male subjects
To be implemented only after approval of the IRB / IEC / Competent 
Authorities
To be implemented immediately in order to eliminate hazard – IRB / IEC / 
Competent Authority to be notified of change with request for approval
Can be implemented without IRB / IEC / Competent Authority approval as 
changes involve logistical or administrative aspects only
Section to be changed
1) 3.3. Exclusion criteria
2) 5.2.3 Safety laboratory parameters
Description of change
1) Period for using highly effective methods of 
birth control was extended from 30 to 90 
days. Consistently, the period were sperm 
donation is not allowed was also extended to 
90 days.
2) GLDH and myoglobin removed
Rationale for change
1) Request from Ethics Committee
2) These parameters are not available at the 
local lab. Safety monitoring is considered 
sufficient with the available parameters. 

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 77 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
11.2
GLOBAL AMENDMENT 2
Date of amendment
14-Jan-2021
EudraCT number
EU number
2020-002321-28
BI Trial number
1411-0013
BI Investigational Medicinal 
Product(s)
BI 474121
Title of protocol
Pharmacokinetics and pharmacodynamic effects of 
different single oral doses of BI 474121 in healthy 
male subjects
To be implemented only after approval of the IRB / IEC / Competent
Authorities
To be implemented immediately in order to eliminate hazard – IRB / IEC / 
Competent Authority to be notified of change with request for approval
Can be implemented without IRB / IEC / Competent Authority approval as 
changes involve logistical or administrative aspects only
Section to be changed
Table 5.2.3: 1 Routine laboratory tests
in section 5.2.3
Title Page
Description of change
For the automatic differential WBC absolute instead 
of relative values will be provided.  
Troponin T test result will be provided irrespective 
of whether CK is increased or not. 
Title Page: Adding phone and fax number of CTL 
and PI
Rationale for change
Adaptations due to local lab requirements
Titel Page: Completion

Boehringer Ingelheim
03 May 2021
BI Trial No.: 1411-0013
c30700234-04
Trial Protocol
Page 78 of 78
Proprietary confidential information © 2021 Boehringer Ingelheim International GmbH or one or more of its affiliated companies
001-MCS-40-106-RD-13 (6.0) / Saved on: 13 Jun 2018
11.3
GLOBAL AMENDMENT 3
Date of amendment
03-May-2021
EudraCT number
EU number
2020-002321-28
BI Trial number
1411-0013
BI Investigational Medicinal 
Product(s)
BI 474121
Title of protocol
Pharmacokinetics and pharmacodynamic effects of 
different single oral doses of BI 474121 in healthy 
male subjects
To be implemented only after approval of the IRB / IEC / Competent 
Authorities
To be implemented immediately in order to eliminate hazard – IRB / IEC / 
Competent Authority to be notified of change with request for approval
Can be implemented without IRB / IEC / Competent Authority approval as 
changes involve logistical or administrative aspects only
Section to be changed
5.4.1
Description of change
Freezing temperature for CSF samples changed from 
“approximately -20°C or below” to 
“approximately -70°C or below”
Rationale for change
Bioanalytical requirement for stability reasons

 
 
 
 
APPROVAL / SIGNATURE PAGE 
 
Document Number: 
 
Technical Version Number:
 
Document Name: 
 
 
 
                                                                                                                 
 
Title: 
 
 
 
 
                                                                                                                   
 
Signatures (obtained electronically) 
 
Meaning of Signature  
Signed by 
Date Signed 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
c30700234
4.0
clinical-trial-protocol-version-04
Pharmacokinetics and pharmacodynamic effects of different single oral doses of BI
474121 in healthy male subjects
Approval-Team Member Medicine
03 May 2021 16:34 CEST
Author-Clinical Trial Leader
03 May 2021 18:47 CEST
Author-Trial Statistician
04 May 2021 09:31 CEST
Verification-Paper Signature
Completion
06 May 2021 09:12 CEST

Boehringer Ingelheim 
Page 2 of 2
Document Number: 
 Technical Version Number:
 
 
 
(Continued) Signatures (obtained electronically) 
 
Meaning of Signature  
Signed by 
Date Signed 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
c30700234
4.0