A Randomized, Double-blind, Phase 3 Comparison of Platinum-based Therapy With TSR-042 and Niraparib Versus Standard of Care Platinum-based Therapy as First-line Treatment of Stage III or IV Nonmucinous Epithelial Ovarian Cancer
Phase: PHASE3
Conditions: Ovarian Neoplasms, Ovarian, Fallopian Tube and Primary Peritoneal Carcinoma
Sponsor: Tesaro, Inc.

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NIRAPARIB (GSK3985771); DOSTARLIMAB (TSR-042) 
3000-03-005/ENGOT-OV44/ GSK 213350 (FIRST) 
The FIRST (First-line ovarian cancer treatment with Niraparib plus TSR-042) Study:  
A RANDOMIZED, DOUBLE-BLIND, PHASE 3 COMPARISON OF PLATINUM-
BASED THERAPY WITH TSR-042 AND NIRAPARIB VERSUS STANDARD OF 
CARE PLATINUM-BASED THERAPY AS FIRST-LINE TREATMENT OF 
STAGE III OR IV NONMUCINOUS EPITHELIAL OVARIAN CANCER 
Sponsor: 
TESARO, Inc., a Glaxo 
Smith Kline Company 
1000 Winter Street, Suite 
3300 
Waltham, MA 02451 
 
TESARO Bio Netherlands B.V, a Glaxo 
Smith Kline Company 
Joop Geesinkweg 901  
1114AB Amsterdam-Duivendrecht  
The Netherlands 
 
Medical Monitor: 
, MD 
 
Direct Phone: 
  
Principal Investigator: 
Anne-Claire Hardy-Bessard, MD, GINECO 
Scientific Coordinator: 
, MD, PhD, GINECO 
Biostatistician: 
, Project Statistician, GSK 
, MD, PhD, GINECO  
CRO: 
 
IND No.: 
126,472  
EudraCT No.: 
2018-000413-20 
EU CT No.: 
2024-510605-28 
NCT No.: 
NCT03602859 
Development Phase: 
3 
Date of Original Protocol: 
27 April 2018 (Version 1.0), 07 May 2018 (Version 2.0) 
Date of Amendment 1: 
11 July 2018 
Date of Amendment 2: 
Date of Amendment 3: 
Date of Amendment 4: 
Date of Amendment 5: 
Date of Amendment 6: 
Date of Amendment 7: 
Date of Amendment 8: 
Date of Amendment 9: 
Date of Amendment 10: 
Version of Protocol: 
01 November 2018 
17 July 2019 
14 January 2020 
19 August 2020 
01 February 2022 
07 June 2024 
24 October 2024 
03 March 2025 
08 Aug 2025 
Version 12.0 
Confidentiality Statement 
All information contained in this document is privileged and confidential to TESARO. Any 
distribution, copying, or disclosure is strictly prohibited without prior written approval by TESARO. 
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SPONSOR SIGNATURE PAGE 
Declaration of Sponsor or Responsible Medical Officer 
Title (Study Number): A Randomized, Double-Blind, Phase 3 Comparison of 
Platinum-Based Therapy with TSR-042 and Niraparib Versus Standard of Care 
Platinum-Based Therapy as First-line Treatment of Stage III or IV Nonmucinous 
Epithelial Ovarian Cancer (3000-03-005/ENGOT-OV44/GSK 213350 [FIRST])  
This study protocol was subjected to critical review and has been approved by the 
Sponsor. The information it contains is consistent with the current risk/benefit evaluation 
of the investigational products and other study treatments as well as with the moral, 
ethical, and scientific principles governing clinical research as set out in the Declaration 
of Helsinki and the guidelines on Good Clinical Practice.  
_____________________________  
 
___________________________ 
Rébécca Phaëton, MD 
 
 
 
 
 
 
 
Date 
DD Month YYYY
 
 
 
 
 
Senior Medical Director, GSK 
The signed page is a separate document. 

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INVESTIGATOR’S AGREEMENT 
I have received and read the Investigator’s Brochures for niraparib and dostarlimab 
(formerly referred to as TSR-042). I have read the 3000-03-005/ENGOT-OV44/GSK 
213350 (FIRST) protocol and agree to conduct the study as outlined. I agree to maintain 
the confidentiality of all information received or developed in connection with this 
protocol.  
 
 
 
 
 
 
 
 
 
 
 
 
 
Printed Name of Investigator 
 
 
 
 
 
 
 
 
 
 
 
 
 
Signature of Investigator 
 
 
 
 
 
 
 
Date 

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PROTOCOL AMENDMENT SUMMARY OF CHANGES 
Table 1: 
Document History 
Document 
Date 
Document Number 
Amendment 10 (Version 12.0) 
08 Aug 2025 
TMF-22277333 
Amendment 09 (Version 11.0) 
03 March 2025 
TMF-21225961 
Amendment 08 (Version 10.0) 
24 October 2024 
TMF-19990252 
Amendment 07 (Version 9.0) 
07 June 2024 
TMF-16341903 
Amendment 06 (Version 8.0) 
01 February 2022 
TMF-14338694 
Amendment 05 (Version 7.0) 
19 August 2020 
TMF-11847898 
Amendment 04 (Version 6.0) 
14 January 2020 
TMF-19350677 
Amendment 03 (Version 5.0) 
17 July 2019 
TMF-1903499 
Amendment 02 (Version 4.0) 
01 November 2018 
TMF-14456931 
Amendment 01 (Version 3.0) 
11 July 2018 
TMF-19350665 
Original Protocol (Version 2.0) 
07 May 2018 
TMF-11847688 
Original Protocol (Version 1.0) 
27 April 2018 
TMF-19361612 
Overall rationale for the current Amendment: This is a substantial amendment to 
 
 
 
  
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Table 2: 
Summary of Changes for Amendment 10 
Section(s) Affected 
Description of Change 
Brief Rationale 
Headers, cover page, 
Protocol Amendment 
Summary of Changes, 
and throughout 
Headers and cover page were updated with 
new document number and amendment 
information; Protocol Amendment 
Summary of Changes section was updated 
to include rationale for this amendment; 
editorial revisions for consistency with 
Sponsor’s ways of working and to add 
clarification and/or remove discrepancies. 
Editorial changes to align with 
the Sponsor’s standard 
protocol template and ways of 
working and for accuracy, 
clarity, conformity, flow, and 
typographical error correction.  
Throughout 
Editorial, administrative, and document 
formatting revisions. 
Minor changes for 
consistency, clarifications, and 
corrections to text. 
Synopsis 
Update of estimated date last participant 
completed to Q3 2029. 
Update of study completion 
date following the 
incorporation of the PACT 
phase. 
Synopsis, 
Section 3.1.1 
Adaption to Study 
Design,  
Section 9.6 Interim 
Analyses, Appendix 1 
Schedule of Events 
Information added to reflect no further 
efficacy analyses will be conducted 
following analysis at DCO date 
31 October 2024 prior to PACT phase for all 
ongoing patients. Consequently, scope of 
data collection is reduced. Adjustments to 
EOT Visit and Safety Follow-up visits prior 
to PACT reflected in the revised schedule of 
events (Table 15). 
To provide information on the 
reduction of scope of data 
collection as a consequence of 
no further efficacy analysis 
will be carried out post DCO 
date 31 October 2024.   
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Section(s) Affected 
Description of Change 
Brief Rationale 
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Section(s) Affected 
Description of Change 
Brief Rationale 
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Section(s) Affected 
Description of Change 
Brief Rationale 
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SYNOPSIS 
Name of Sponsor/Company: TESARO, Inc., a Glaxo Smith Kline Company 
Name of Investigational Treatment Combination: Niraparib and dostarlimab (formerly 
referred to as TSR-042) 
Name of Active Ingredients: Niraparib and dostarlimab  
TITLE OF STUDY: A Randomized, Double-Blind, Phase 3 Comparison of Platinum-Based 
Therapy with TSR-042 and Niraparib Versus Standard of Care Platinum-Based Therapy as 
First-line Treatment of Stage III or IV Nonmucinous Epithelial Ovarian Cancer 
(3000-03-005/ENGOT-OV44/GSK 213350) (FIRST)  
Study Center(s): Approximately 225 sites in approximately 25 countries 
Principal Investigator: Anne-Claire Hardy-Bessard, MD, GINECO 
Studied Period (years): 
Estimated date first participant enrolled: Q3 
2018  
Estimated date last participant completed: Q3 
2029  
Phase of Development:  
Phase 3 
Objectives: 
Primary Objective 
• 
To compare the progression free survival (PFS) of platinum-based combination 
therapy, dostarlimab, and niraparib treatment (Arm 3) to platinum-based 
combination therapy and niraparib treatment (Arm 2) in participants with Stage III 
or IV high-grade nonmucinous epithelial ovarian cancer. 
 
 
Secondary Objectives 
 
 
• 
Overall survival (OS, 
 
• 
Blinded Independent Central Review (BICR)-determined PFS per RECIST v1.1 
criteria 
• 
Health related quality of life (HRQoL) 
• 
Time to first subsequent therapy (TFST) 
• 
Time to second subsequent therapy (TSST)  
• 
Time from randomization to the earliest date of assessment of progression after 
initiation of subsequent anticancer therapy following study treatment or death by 
any cause (PFS2) 
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• 
Objective response rate (ORR) per 
 
  
• 
Duration of response (DOR) per 
 
  
• 
Disease control rate (DCR) per 
 
  
• 
Pharmacokinetics (PK) and immunogenicity of dostarlimab 
• 
PK of niraparib 
Secondary objectives for platinum-based combination therapy (Arm 1), platinum-based 
combination therapy and niraparib (Arm 2) and platinum-based combination therapy, 
dostarlimab, and niraparib (Arm 3) for all participants will evaluate: 
• 
Safety and tolerability  
Exploratory Objectives 
Methodology: 
Overall Study Design 
This is a global, multicenter, randomized, double-blind, controlled Phase 3 study in 
participants with newly diagnosed, Stage III or IV high-grade nonmucinous epithelial ovarian, 
fallopian tube, or peritoneal cancer (collectively referred to as “ovarian cancer”). The currently 
recommended standard-of-care (SOC) for the first-line treatment of Stage III or IV ovarian 
cancer is a combination of paclitaxel-carboplatin, with or without concurrent and maintenance 
bevacizumab. The use of bevacizumab must be determined prior to randomization. 
The study is open to participants with inoperable ovarian cancer, participants who have 
macroscopic residual disease at the end of the primary debulking surgery (PDS) and have 
recovered from PDS and participants for whom platinum-based combination neoadjuvant 
chemotherapy (NACT) is planned. Participants with Stage IIIC disease that has been 
completely resected (also known as complete cytoreduction score of ‘0’ [CC0]) are eligible if 
the following criteria is present: aggregate ≥5 cm extra-pelvic disease during PDS as assessed 
by the Investigator. The use of bevacizumab is optional and permitted if considered SOC per 
local treatment guidelines and/or practices. 
All eligible enrolled participants will receive SOC during the Cycle 1 Chemotherapy Run-In 
Period before randomization at Cycle 2.  
Treatment Arm 1 consists of SOC and intravenous (IV) dostarlimab placebo followed by oral 
niraparib placebo and IV dostarlimab placebo in the maintenance phase of treatment. Arm 2 
consists of SOC and IV dostarlimab placebo followed by oral niraparib and IV dostarlimab 
placebo maintenance therapy. Arm 3 consists of SOC and IV dostarlimab followed by oral 
niraparib and IV dostarlimab maintenance therapy.  
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This study is designed to enable rapid adaptation to evolving treatment paradigms for 
participants with advanced ovarian cancer. This ensures that study participants will have access 
to the most current regimen with or without investigational treatment while maintaining the 
integrity of the study. Full details on adaptations to the study design are located in the protocol. 
In Amendment 2, dated 01 November 2018, 
 
 
 
 
 There was no change to participants with 
BRCAwt HRRpos and BRCAwt HRRneg/not determined status; they continued to be 
randomized to Arm 1, Arm 2, or Arm 3. Arm 1 BRCAmut participants who were in the 
Chemotherapy Treatment Period when the amendment was implemented completed the 6 
cycles of chemotherapy. Following completion of the Chemotherapy Treatment Period and 
confirmation of adequate hematologic parameters, these participants were allowed to start 
niraparib maintenance therapy as "follow-up anticancer treatment" at the Investigator’s 
discretion. Arm 1 BRCAmut participants who were in the Maintenance Treatment Period when 
the amendment was implemented were allowed to start niraparib maintenance therapy as 
"follow-up anticancer treatment" if the time after Cycle 6 Day 1 of the Chemotherapy 
Treatment Period was ≤12 weeks. In order to facilitate this adaptation, Investigators were 
unblinded for Arm 1 BRCAmut participants enrolled prior to implementation of this 
amendment. 
 
 
 
 
 
 
 Therefore, the SOC for treatment of Stage III or IV 
ovarian cancer was updated to include the administration of a PARP inhibitor with or without 
bevacizumab during the maintenance period.  
As a result, following Sponsor and Steering Committee discussions, participants were not 
enrolled into Arm 1 after Amendment 4 was approved at each site. Participants in Arm 1, 
Chemotherapy Treatment Period who are receiving bevacizumab when Amendment 4 is 
implemented, may continue the 6 cycles of chemotherapy. Following completion of the 
Chemotherapy Treatment Period and confirmation of adequate hematologic parameters, those 
participants may start bevacizumab maintenance therapy at the Investigator’s discretion. 
Participants in Arm 1, Maintenance Treatment Period who are receiving bevacizumab when 
Amendment 4 is implemented may continue bevacizumab maintenance therapy at the 
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Investigator’s discretion. Investigators will remain blinded for those participants enrolled in 
Arm 1 and receiving bevacizumab at the time of implementation of Amendment 4. 
Participants in Arm 1, Chemotherapy Treatment Period not receiving bevacizumab when 
Amendment 4 is implemented, may continue the 6 cycles of chemotherapy. Following 
completion of the Chemotherapy Treatment Period and confirmation of adequate hematologic 
parameters, those participants may start niraparib maintenance therapy as "follow-up 
anticancer treatment" at the Investigator’s discretion. Participants in Arm 1, Maintenance 
Treatment Period not receiving bevacizumab when Amendment 4 is implemented may start 
niraparib maintenance therapy as "follow-up anticancer treatment" if the time after Cycle 6 
Day 1 of the Chemotherapy Treatment Period is ≤12 weeks. Participants will be permitted to 
remain on study until withdrawal of consent, sponsor decision to terminate study or death. 
Participants who do not elect to receive niraparib or bevacizumab maintenance will be 
discontinued from the study treatment and given the option to stay in the study for follow up. 
Investigators will be unblinded for those participants enrolled in Arm 1 and not receiving 
bevacizumab at the time of implementation of Amendment 4. The schedule of events for these 
participants is shown in Table 18.  
In total, 
 
 
 
 
 
  
Following the analysis conducted at the 31 October 2024, DCO date, no further efficacy 
analyses will be conducted for the study. Consequently, the scope of data collection is reduced 
for those ongoing participants still receiving study treatment and in follow-up, aligning with 
the prior to PACT schedule of events.  
Participants may access the treatment outside of the study protocol prior to PACT by the DCO 
date for the final analysis by a rollover study, Managed Access route, or other potential 
mechanisms of access, or if commercially available and accessible. Following the DCO date 
for the final analysis, Study 213350 (FIRST) may move into the PACT phase where the study 
remains open only to provide continued access to study treatment for participants who are 
continuing to derive clinical benefit in the opinion of the Investigator and cannot access the 
treatment outside of the study protocol by the time of the final analysis DCO date. At that time, 
the collection of new data for participants who no longer receive study intervention will stop 
entirely and will be considered to have completed the study. The clinical study database will be 
closed to new data following the DCO date for the final analysis. Participants still clinically 
benefiting from study intervention at the time of the PACT phase may continue to receive 
study treatment and only serious adverse events (SAEs), AEs leading to study intervention 
discontinuation, overdose, adverse events of special interest (AESIs), and pregnancy cases will 
be reported directly to the sponsor. Alternative continued treatment access outside of this study 
may be implemented, as it becomes available. 
 
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b All participants previously randomized to placebo and not receiving bevacizumab will be unblinded 
and provided the option to receive niraparib maintenance if they have received chemotherapy or 
discontinued chemotherapy ≤12 weeks. 
Pre-Screening Period 
During the Pre-Screening Period, participants may sign a pre-Screening informed consent form 
consenting to collection of the required tumor tissue sample 
 
 
 
 The Pre--Screening Period can take place within the 14 days prior to the 
Screening Period, defined as the date of signing the main informed consent, but does not have 
to encompass the full period. A participant can move to the Screening Period once deemed 
able.  
Screening Period 
During the Screening Period, participants will sign the main consent form and complete all 
assessments required to determine eligibility into the study. The Screening Period is within 28 
days prior to Cycle 1 Day 1 (C1D1) of the Chemotherapy Run-In Period.  
Chemotherapy Run-In Period (Cycle 1) 
Prior to randomization, all participants will receive 1 cycle of paclitaxel-carboplatin during a 
Chemotherapy Run-In Period. Participants may also receive bevacizumab with paclitaxel-
carboplatin as part of SOC per local practice. However, bevacizumab must not be administered 
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less than 28 days before or 28 days following major surgery, and post-operative incisions must 
be fully healed. The determination to use bevacizumab must be made prior to randomization. 
Participants will be randomized following Cycle 1, prior to treatment in Cycle 2 during the 
Chemotherapy Treatment Period. Randomization may occur up to one week prior to Cycle 2 
Day 1. 
Intraperitoneal (IP) chemotherapy and weekly paclitaxel will not be allowed. 
Chemotherapy Treatment Period (Cycles 2 to 6) 
Prior to the chemotherapy administration of Cycle 2, all of the following criteria must be met: 
• 
Absolute neutrophil count (ANC) ≥1,500 cells/µL, or ≥1,000 cells µL if 
granulocyte-colony stimulating factor (G-CSF) is to be administered 
• 
Platelet count ≥100,000 cells/µL 
• 
Hemoglobin ≥8 g/dL 
Thereafter, re-treatment criteria for remaining chemotherapy Cycles 3 to 6 should be in 
accordance with treatment guidelines per local practice. 
Following randomization, participants who have inoperable disease or who have undergone 
PDS will receive cycles 2 to 6 of paclitaxel-carboplatin, for a total of 6 cycles of chemotherapy 
inclusive of Cycle 1. Participants will also receive dostarlimab/placebo in combination with 
paclitaxel-carboplatin started with Cycle 2 of chemotherapy, for a total 5 cycles. Bevacizumab 
may continue per local practice. 
Participants for whom NACT is planned will receive 3 to 4 cycles of paclitaxel-carboplatin 
prior to interval debulking surgery (inclusive of Cycle 1) and 2 to 3 additional cycles of 
paclitaxel-carboplatin following surgery for a maximum of 6 cycles of chemotherapy that 
cannot be extended. Interval debulking surgery planned after 6 cycles of chemotherapy should 
be discussed with the Sponsor. These participants will also receive dostarlimab/placebo, which 
will be started with Cycle 2 of chemotherapy, for a total of 5 cycles. Chemotherapy and 
dostarlimab/placebo will resume upon recovery of surgery. Participants for whom NACT is 
planned may receive bevacizumab with paclitaxel-carboplatin per local practice; however, 
bevacizumab must not be administered less than 28 days before or 28 days following major 
surgery, and post-operative incisions must be fully healed. 
IP chemotherapy and weekly paclitaxel will not be allowed. 
Maintenance Treatment Period  
Participants who complete the Chemotherapy Treatment Period without progressive disease 
(PD) will start the Maintenance Treatment Period 3 weeks after Cycle 6 Day 1. 
Dostarlimab/placebo ± bevacizumab will also continue in the Maintenance Treatment Period in 
combination with oral niraparib maintenance treatment, per study schedule. However, the start 
of niraparib will be delayed at least 6 weeks after Cycle 6 Day 1 and up to 9 weeks after to 
allow for adequate recovery of hematologic toxicity.  

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Prior to starting the first dose of oral niraparib maintenance treatment, participants must have a 
complete blood count (CBC) that demonstrate adequate recovery from hematologic toxicity 
from chemotherapy: 
• 
Absolute neutrophil count ≥1,500 cells/μL 
• 
Platelet count ≥100,000/μL 
• 
Hemoglobin ≥9 g/dL 
• 
Blood pressure (BP) <150/100 mmHg 
Weekly CBC is to be performed for the first 4 weeks from the start of niraparib in the 
Maintenance Treatment Period. 
The recommended order of administration is provided below, unless local clinical practice or 
institutional policies differ:  
• 
During the Chemotherapy Treatment Period, 
 
 
.  
• 
During the Maintenance Treatment Period, 
 
 
Study Conduct 
Treatment Cycles 
Treatment cycles are 21 days long. 
Visits should occur within ±3 days of the scheduled visit. This window also applies to study 
procedures, with all procedures allowed to be performed up to ±3 days of the scheduled visit. 
All times should be recorded using the 24-hour clock (e.g., 23:20, not 11:20 PM). 
Interval Debulking Surgery (IDS) 
Participants for whom NACT is planned will receive 3 to 4 cycles of chemotherapy treatment 
prior to IDS (inclusive of Cycle 1) and an additional 2 to 3 cycles following surgery for a 
maximum of 6 cycles of chemotherapy that cannot be extended. Interval debulking surgery 
planned after 6 cycles of chemotherapy should be discussed with the Sponsor. Initiation of the 
subsequent cycles post-IDS will be upon post-operative recovery of the participant. 
Bevacizumab should not be administered less than 28 days before or 28 days following major 
surgery. Additionally, participants indicated for IDS will also have a pre-operative scan during 
the chemotherapy period. 
Radiographic Evaluation for Primary Outcome 
All participants are required to undergo radiographic evaluation throughout the study. RECIST 
v1.1 tumor assessment via computed tomography (CT) or magnetic resonance imaging (MRI) 
scan of the chest/abdomen/pelvis and clinically indicated areas is required at Screening, prior 
to IDS (if applicable), prior to the start of the maintenance period, and at regular intervals 
throughout the maintenance. If there are lesions in the chest and/or clinically indicated areas at 
Screening, then these areas should be scanned at each subsequent timepoint. Otherwise, only 
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abdomen/pelvis are required after Screening. During the Maintenance Treatment Period, 
imaging to assess disease status must occur at C1D1 (±14 days) of the Maintenance Treatment 
Period and then every 4 months (±7 days) for 24 months, followed by every 6 months 
(±7 days) during the third year and every year thereafter until PD or initiation of follow-up 
anticancer therapy. Tumor assessments should occur according to this schedule, regardless of 
whether study treatment is discontinued (i.e., counting from C1D1 of the Chemotherapy or 
Maintenance Treatment Period, as appropriate). Additional unscheduled RECIST v1.1 CT or 
MRI scans (of any anatomical region that may be clinically indicated) must be performed 
whenever disease progression is suspected based on increasing cancer antigen 125 (CA 125) 
values or other suspicious symptoms. PD will not be diagnosed in the case of CA 125 
progression or suspicious symptoms in the absence of radiologic evidence of PD. Following 
completion of 3 years of maintenance therapy, participants will be evaluated clinically with 
annual scans and additional unscheduled scans for suspicion of disease progression based on 
increases in CA 125 or other suspicious symptoms. Participants may be considered for 
treatment beyond 3 years in consultation with the Sponsor. Prior to PACT (included in 
Amendment 10), RECIST v1.1. scans may occur at the time of clinical suspicion of disease 
progression or at an annual interval, whichever occurs first according to the PI discretion and 
local practice guidelines.  
 
 
 Clinically stable 
participants are those with no signs or symptoms of clinically significant or rapid progression 
of disease, including worsening of laboratory values or decline in performance status (ECOG) 
and no progressive tumor at critical anatomical sites [e.g., cord compression, intracranial tumor 
hemorrhage] requiring urgent medical intervention. 
 
 
Patient-Reported Outcomes and Health-related Quality of Life 
The following HRQoL assessments will be obtained: the European Quality of Life 
5-Dimension 5-Level Scale (EQ-5D-5L), the European Organization for Research and 
Treatment of Cancer Quality of Life Questionnaire C30 (EORTC-QLQ-C30), and the 
EORTC-QLQ Ovarian Cancer Module OV28 (EORTC-QLQ-OV28). These will be collected 
at the following time points: 
• 
Chemotherapy Run-In (21-day cycle): C1D1. 
• 
Chemotherapy Treatment (21-day cycles): Cycle 2/Day 1, and every 2 cycles 
thereafter (Cycle 4/Day 1, ending Cycle 6/Day 1).  
• 
Maintenance Treatment (21-day cycles): Day 1 of every cycle (i.e., every 21 days 
[Q21D]) ±7 days) for the first 3 cycles, Day 1 of every 3 cycles (i.e., every 
9 weeks ±7 days) through 15 cycles, Cycle 17 and every 6 cycles thereafter until 
PD or end of study treatment. Not applicable prior to PACT (included in 
Amendment 10). 
• 
Post-treatment: For participants who discontinue treatment, HRQoL assessments 
should be collected at the end of treatment (EOT) Visit, 30-day post EOT 
(±7 days) Safety Follow-up Visit, 90-day post EOT (±14 days) Long-Term 
Follow-up Visit, and every 180 days (±14 days) after the Long-Term Follow-up 
Visit (every other post-treatment assessment), which will continue until death or 
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the end of study data collection. Not applicable prior to PACT (included in 
Amendment 10). 
All HRQoL assessments during the Chemotherapy Treatment and Maintenance Periods should 
be collected in clinic, on the day of study drug administration, prior to dosing or clinical 
procedures. They may be completed remotely if the participant is no longer actively returning 
to the site. 
Biomarker, Pharmacokinetic, and Immunogenicity Assessment 
PACT Phase 
Following the final DCO date, the study may move into the PACT phase. Participants who 
continue to receive study treatment during the PACT phase will be monitored and will receive 
follow-up care in accordance with standard local clinical practice. Assessments will revert to 
the standard of care at a participant’s particular study site. Study treatment will continue for up 
to 3 years from the final DCO date, or until transition to an alternative method of continued 
treatment access (outside of the study), or manufacturing of the product ceases, or the study 
intervention discontinuation criteria are met, whichever occurs first. Alternative continued 
treatment access outside of this study may be implemented, as it becomes available. 
End of Treatment Visit and Safety Follow-up Visit 
All participants will undergo an EOT visit within 7 days after the last dose of study treatment 
or at the time of disease progression, whichever occurs first. A safety follow-up visit will be 
conducted 30 days (±7 days) after the last dose of study treatment or before the initiation of 
follow-up anticancer therapy. Safety follow-up visits are required only for those participants 
who have not started a follow-up anticancer therapy. After the 30-day (±7 days) safety follow-
up visit, all participants will enter the post-treatment follow-up period of telephone assessment 
for survival status, documentation and management of any AEs/SAEs), adverse event of 
special interest (AESI), and follow-up anticancer therapy every 90 (±14) days until participant 
discontinuation of study, withdrawal of consent, or death. 
 
 
If a participant 
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discontinues treatment within 28 days of the scan that indicates PD, then the EOT scan will not 
be performed.  
A safety follow-up visit is not carried out for a participant who transitions to continue 
treatment outside of the study prior to PACT. For a participant discontinuing treatment in the 
PACT phase, no end of treatment or safety follow-up visit is required. 
Safety Assessments 
Safety assessments conducted throughout the Chemotherapy Treatment Period and 
Maintenance Treatment Period include collection of treatment emergent adverse events 
(TEAEs), serious adverse events (SAEs), treatment discontinuations or dose delays or 
reductions due to adverse events (AEs), ECOG performance, clinical laboratory results 
(hematology and chemistry), vital sign measurements, observations during physical 
examination, and use of concomitant medications.  
All AEs are required to be captured through 30 days after cessation of study treatment. SAEs 
are required to be captured through 90 days after the last dose of study treatment (or for a 
minimum of 30 days post-treatment discontinuation if the participant starts alternative 
anticancer therapy). Investigators must continue to directly report AESIs during treatment with 
niraparib and for 90 days after the last dose of niraparib.  If the Investigator learns of an AESI 
after the last dose of niraparib, the Investigator must promptly notify the Sponsor. Any 
pregnancies that occur within 180 days post-treatment discontinuation will be captured for all 
participants (not only participants in PACT Phase). If applicable, when a patient transitions off 
study to continue treatment prior to PACT, safety reporting should be via the reporting 
mechanism applicable to the access route outside the study. Once the specified safety reporting 
period has elapsed, investigators are not obliged to actively seek information on AEs, SAEs or 
AESIs, however if the Investigator learns of an AESI or an SAE that is considered reasonably 
related to the study, the Investigator must promptly notify the Sponsor.  All AEs and SAEs 
experienced by a participant, regardless of the suspected causality, will be monitored until the 
AE or SAE has resolved, until any abnormal laboratory values have returned to baseline or 
normalized, until there is a satisfactory explanation for the change(s) observed, until the 
participant is lost to follow-up or withdraws consent, or until the participant has died. 
The niraparib AESIs for this study are myelodysplastic syndrome (MDS), acute myeloid 
leukemia (AML), and secondary cancers (new malignancies other than MDS/AML). There are 
no AESIs for dostarlimab. AESIs must be reported to the Sponsor as soon as the Investigator 
becomes aware of them.  
For PACT, Investigators must report all SAEs, AEs leading to study treatment discontinuation, 
overdose, AESIs, and pregnancy cases via paper forms directly to the Sponsor.    
Number of Participants (Randomized): 
 
 
Criteria for Inclusion: 
To be considered eligible to participate in this study the following requirements must be met: 
1. Participants must be female, ≥18 years of age, able to understand the study procedures, 
and agree to participate in the study by providing written informed consent. 
2. Participants with a histologically confirmed diagnosis of high-grade nonmucinous 
epithelial ovarian (serous, endometrioid, clear cell, carcinosarcoma, and mixed 
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pathologies), fallopian tube, or primary peritoneal cancer that is Stage III or IV 
according to the International Federation of Gynecology and Obstetrics (FIGO) or 
tumor, node and metastasis (TNM) staging criteria [i.e., American Joint Committee on 
Cancer]. 
3. All participants with Stage IV disease are eligible. This includes those with inoperable 
disease, those who undergo PDS (R0 or macroscopic disease), or those for whom 
NACT is planned. 
4. Participants with Stage III are eligible if they meet one or more of the following 
criteria: 
a. Stage IIIC participants with CC0 resection if they meet the following 
criteria: aggregate ≥5 cm extra-pelvic disease during PDS as assessed by the 
Investigator  
b. All participants with inoperable Stage III disease 
c. All Stage III participants with macroscopic residual tumor (per Investigator 
judgment) following PDS  
d. All Stage III participants for whom NACT is planned. 
5. Participant must provide a blood sample for 
 at Pre-Screening or 
Screening.  
6. Participant must provide sufficient tumor tissue sample 
 
 
  
7. Participants of childbearing potential must have a negative serum or urine pregnancy 
test (beta human chorionic gonadotropin) within 3 days prior to receiving the first dose 
of study treatment. 
8. Participants must be postmenopausal, free from menses for >1 year, surgically 
sterilized, or willing to use highly effective contraception to prevent pregnancy or must 
agree to abstain from activities that could result in pregnancy throughout the study, 
starting with enrollment through 180 days after the last dose of study treatment. 
9. Participants must have adequate organ function, defined as follows (Note: CBC test 
should be obtained without transfusion or receipt of stimulating factors within 2 weeks 
before obtaining Screening blood sample): 
a. Absolute neutrophil count ≥1,500/µL 
b. Platelet count ≥100,000/µL 
c. Hemoglobin ≥9 g/dL 
d. Serum creatinine ≤1.5×upper limit of normal (ULN) or calculated creatinine 
clearance ≥60 mL/min using the Cockcroft-Gault equation 
e. Total bilirubin ≤1.5×ULN or direct bilirubin ≤1.5×ULN 
f. Aspartate aminotransferase and alanine aminotransferase (ALT) ≤2.5×ULN unless 
liver metastases are present, in which case they must be ≤5×ULN 
10. Participants must have an ECOG score of 0 or 1. 
11. Participants must have normal BP or adequately treated and controlled hypertension 
(systolic BP ≤140 mmHg and/or diastolic BP ≤90 mmHg). 
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12. Participants must agree to complete HRQoL questionnaires throughout the study. 
13. Participants must be able to take oral medication. 
Criteria for Exclusion: 
Participants will not be eligible for study entry if any of the following criteria are met: 
1. Participant has mucinous, germ cell, transitional cell, or undifferentiated tumor. 
2. Participant has low-grade or Grade 1 epithelial ovarian cancer. 
3. Stage III participant with CC0 resection after PDS (i.e., no macroscopic residual 
disease, unless inclusion criterion #4a is met). 
4. Participant has not adequately recovered from prior major surgery. 
5. Participant has a known condition, therapy, or laboratory abnormality that might 
confound the study results or interfere with the participant’s participation for the full 
duration of the study treatment in the opinion of the Investigator. 
6. Participant is pregnant or is expecting to conceive children while receiving study drug 
or for up to 180 days after the last dose of study drug. Participant is breastfeeding or is 
expecting to breastfeed within 30 days of receiving the final dose of study drug 
(women should not breastfeed or store breastmilk for use, during niraparib treatment 
and for 30 days after receiving the final dose of study treatment). 
7. Participant has known active central nervous system metastases, carcinomatous 
meningitis, or both.  
8. Participant has clinically significant cardiovascular disease (e.g., significant cardiac 
conduction abnormalities, uncontrolled hypertension, myocardial infarction, 
uncontrolled cardiac arrhythmia or unstable angina <6 months to enrollment, New 
York Heart Association Grade 2 or greater congestive heart failure, serious cardiac 
arrhythmia requiring medication, Grade 2 or greater peripheral vascular disease, and 
history of cerebrovascular accident within 6 months). 
9. Participant has a bowel obstruction by clinical symptoms or CT scan, subocclusive 
mesenteric disease, abdominal or gastrointestinal fistula, gastrointestinal perforation, 
or intra-abdominal abscess.  
10. Participant initiating bevacizumab as SOC has proteinuria as demonstrated by urine 
protein:creatinine ratio ≥1.0 at Screening or urine dipstick for proteinuria ≥2 
(participants discovered to have ≥2 proteinuria on dipstick at baseline should undergo 
a 24-hour urine collection and must demonstrate <2 g of protein in 24 hours to be 
eligible). 
11. Participant has any known history or current diagnosis of MDS or AML. 
12. Participant has been diagnosed and/or treated with any therapy for invasive cancer 
<5 years from study enrollment, completed adjuvant chemotherapy and/or targeted 
therapy (e.g., trastuzumab) less than 3 years from enrollment, or completed adjuvant 
hormonal therapy less than 4 weeks from enrollment. Participants with definitively 
treated non-invasive malignancies such as cervical carcinoma in situ, ductal carcinoma 
in situ, Grade 1 or 2, Stage I endometrial cancer, or non-melanomatous skin cancer are 
allowed.  
13. Participant is at increased bleeding risk due to concurrent conditions (e.g., major 
injuries or major surgery within the past 28 days prior to start of study treatment and/or 

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history of hemorrhagic stroke, transient ischemic attack, subarachnoid hemorrhage, or 
clinically significant hemorrhage within the past 3 months). 
14. Participant is immunocompromised. Participants with splenectomy are allowed. 
Participants with known human immunodeficiency virus (HIV) are allowed if they 
meet all of the following criteria: 
a. Cluster of differentiation 4 ≥350/µL and viral load <400 copies/mL 
b. No history of acquired immunodeficiency syndrome-defining opportunistic 
infections within 12 months prior to enrollment 
c. No history of HIV-associated malignancy for the past 5 years 
d. Concurrent antiretroviral therapy as per the most current National Institutes of 
Health (NIH) Guidelines for the Use of Antiretroviral Agents in Adults and 
Adolescents Living with HIV started >4 weeks prior to study enrollment. 
15. Participant has known active hepatitis B (e.g., hepatitis B surface antigen reactive) or 
hepatitis C (e.g., hepatitis C virus ribonucleic acid [qualitative] is detected). 
16. Participant is considered a poor medical risk due to a serious, uncontrolled medical 
disorder, non-malignant systemic disease, or uncontrolled infection. Specific examples 
include, but are not limited to, history of non-infectious pneumonitis that required 
steroids, current pneumonitis, uncontrolled autoimmune disease, uncontrolled 
ventricular arrhythmia, recent myocardial infarction within 90 days of consent, 
uncontrolled major seizure disorder, unstable spinal cord compression, superior vena 
cava syndrome, or any psychiatric or substance abuse disorders that would interfere 
with cooperation with the requirements of the study (including obtaining informed 
consent). 
17. Participant has had investigational therapy administered within 4 weeks or within a 
time interval less than at least 5 half-lives of the investigational agent, whichever is 
longer, prior to the first scheduled day of dosing in this study. 
18. Participant has received a live vaccine within 14 days of planned start of study therapy. 
Seasonal influenza vaccines that do not contain live viruses are allowed. 
19. Participant has a known contraindication or uncontrolled hypersensitivity to the 
components of paclitaxel, carboplatin, niraparib, bevacizumab, dostarlimab, or their 
excipients. 
20. Prior treatment for high-grade nonmucinous epithelial ovarian, fallopian tube, or 
peritoneal cancer (immunotherapy, anticancer therapy, radiation therapy). 
21. Participant has an active autoimmune disease that has required systemic treatment in 
the past 2 years. Replacement therapy is not considered a form of systemic therapy 
(e.g., thyroid hormone or insulin). 
22. Participant has a diagnosis of immunodeficiency or is receiving systemic steroid 
therapy or any other form of systemic immunosuppressive therapy within 7 days prior 
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Duration of Treatment: 
Planned Study Duration: Approximately 94 months (time from first patient enrolled until last 
patient last visit).  
Planned Treatment Duration: Participants who continue to derive benefit from study 
treatment based on continuation of best overall response indicated by imaging, remain 
clinically stable, and are willing to continue study visits and assessments may continue to 
receive niraparib and/or dostarlimab/placebo beyond 3 years following consultation with the 
investigator and the Sponsor. Bevacizumab (administered during the chemotherapy portion and 
maintenance portion) may be continued for up to 15 months or a total of 22 consecutive or 
non-consecutive cycles (inclusive of bevacizumab administered during the Chemotherapy 
Treatment Period) as per local practice and in the absence of PD, unacceptable toxicity, 
participant withdrawal, or Investigator’s decision. 
For PACT, study treatment will continue for up to 3 years from the final DCO date, or until 
transition to an alternative method of continued treatment access (outside of the study), or the 
manufacturing of the product ceases, or a study intervention discontinuation criteria is met 
including unacceptable toxicity, participant withdrawal, or Investigator’s decision, whichever 
occurs first. Alternative continued treatment access outside of this study may be implemented, 
as it becomes available.  
Criteria for Evaluation: 
Efficacy Analysis 
The comparison of interest in this study is Arm 3 to Arm 2. 
 
  
Primary Efficacy Endpoint 
The primary efficacy endpoint PFS, is defined as the time from the date of randomization to 
the date of first documentation of progression or death by any cause, whichever occurs first. 
Secondary Efficacy Endpoints 
The following secondary efficacy endpoints will be evaluated: 
• 
Overall survival (OS, 
 
• 
BICR 
 
• 
The absolute scores and change from baseline in the EQ-5D-5L Visual Analogue 
Score (VAS) and Health Utility Index (HUI) HRQoL assessments 
• 
The absolute scores and change from baseline in the EORTC-QLQ-C30, and 
EORTC-QLQ-OV28 HRQoL assessments 
• 
TFST, defined as the time from the date of randomization to the start date of the 
first subsequent anticancer therapy or death by any cause, whichever occurs first 
• 
TSST, defined as the time from the date of randomization to the start date of the 
second subsequent anticancer therapy or death by any cause, whichever occurs 
first 
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• 
PFS2, defined as the time from the date of randomization to the date of first PD 
per Investigator’s assessment after initiation of subsequent anticancer therapy or 
death by any cause, whichever occurs first 
• 
ORR, 
 
 
  
• 
DOR, 
 
 
  
• 
DCR, 
 
  
Safety Analysis (Secondary Endpoint) 
Interim Analysis 
Planned periodic safety analyses will be conducted by the Independent Data Monitoring 
Committee (IDMC) 
 
Final Analysis 
A final analysis focusing on safety at the time of final DCO will be performed. 
Biomarker Analysis 
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Immunogenicity Analysis 
PK Analysis 
Statistical Methods: 
Sample Size Considerations  
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Analysis Populations: 
• 
The Intent to Treat (ITT) Population consists of all randomized participants. Any 
deceased participants randomized in error with death prior to randomization will be 
excluded from the population. Participants will be analyzed as randomized. 
• 
The Safety Analysis Population includes all randomized participants who received at 
least 1 dose of study treatment after randomization. Participants will be analyzed 
according to the treatment that they actually received. 
• 
The PK Analysis Population is defined as all participants in Arm 2 (niraparib only) and 
Arm 3 (both niraparib and dostarlimab) who received at least 1 dose of either drug and 
have at least 1 measurable post dose PK result. PK populations are defined separately 
for niraparib and dostarlimab. 
• 
 
 
Primary Efficacy Analysis 
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TABLE OF CONTENTS 
SPONSOR SIGNATURE PAGE ...................................................................................... 2 
INVESTIGATOR’S AGREEMENT ................................................................................... 3 
PROTOCOL AMENDMENT SUMMARY OF CHANGES ................................................. 4 
SYNOPSIS ...................................................................................................................... 9 
TABLE OF CONTENTS ................................................................................................ 26 
LIST OF TABLES .......................................................................................................... 31 
LIST OF FIGURES ........................................................................................................ 33 
LIST OF ABBREVIATIONS AND DEFINITIONS OF TERMS ........................................ 34 
1. 
INTRODUCTION .................................................................................................... 41 
1.1. 
Biology of Ovarian Cancer .......................................................................... 41 
1.2. 
First-Line Chemotherapy for Advanced Ovarian Cancer ............................. 43 
1.3. 
Background of Niraparib ............................................................................. 46 
1.3.1. 
Baseline Body Weight and Platelet Count as Predictors of 
Thrombocytopenia ....................................................................... 48 
1.4. 
Background of Dostarlimab ......................................................................... 49 
1.4.1. 
Nonclinical Experience ................................................................. 49 
1.4.2. 
Clinical Experience ...................................................................... 50 
1.4.2.1. 
Dostarlimab Monotherapy........................................... 51 
1.4.2.2. 
Investigational Therapeutic Combinations with 
Dostarlimab ................................................................ 52 
1.5. 
Combination Therapies Proposed in the Current Trial................................. 52 
1.5.1. 
Addition of PD-1 Inhibitor to Chemotherapy ................................. 52 
1.5.1.1. 
Nonclinical .................................................................. 52 
1.5.1.2. 
Clinical ........................................................................ 53 
1.5.2. 
Addition of anti-PD-1 and PD-L1 Inhibitor to PARP 
Inhibitor ........................................................................................ 53 
1.5.2.1. 
Nonclinical .................................................................. 53 
1.5.2.2. 
Clinical ........................................................................ 54 
1.5.3. 
Combination of PD-1 inhibitor and Bevacizumab ......................... 55 
1.5.4. 
Combination of Niraparib and Bevacizumab ................................ 56 
1.5.5. 
Rationale for Combination Therapies Proposed ........................... 57 
1.6. 
Rationale for Current Study ........................................................................ 57 
2. 
TRIAL OBJECTIVES AND PURPOSE ................................................................... 59 
2.1. 
Primary Objective ....................................................................................... 59 
2.2. 
Secondary Objectives ................................................................................. 59 
2.3. 
Exploratory Objectives ................................................................................ 59 
3. 
INVESTIGATIONAL PLAN ..................................................................................... 60 
3.1. 
Overall Study Design .................................................................................. 60 
3.1.1. 
Adaptation to Study Design ......................................................... 60 
3.2. 
Number of Participants ............................................................................... 65 

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3.3. 
Treatment Assignment ................................................................................ 65 
3.3.1. 
Chemotherapy Run-In and Treatment Period .............................. 65 
3.3.2. 
Maintenance Treatment Period .................................................... 66 
3.3.3. 
Duration of Treatment .................................................................. 70 
3.3.3.1. 
Planned Study Conduct Duration................................ 70 
3.3.3.2. 
Planned Study Treatment Duration ............................. 70 
3.4. 
Dose Adjustment Criteria ............................................................................ 71 
3.4.1. 
Niraparib ...................................................................................... 71 
3.4.2. 
Dostarlimab ................................................................................. 73 
3.4.3. 
Bevacizumab ............................................................................... 78 
3.4.4. 
Carboplatin and Paclitaxel ........................................................... 78 
3.5. 
Criteria for Study Termination ..................................................................... 78 
3.6. 
Study Conduct ............................................................................................ 78 
3.6.1. 
Schedule of Events ...................................................................... 78 
3.6.2. 
Procedures and Assessments ..................................................... 79 
3.7. 
End-of-Study Definition ............................................................................... 84 
4. 
SELECTION AND WITHDRAWAL OF PARTICIPANTS ......................................... 85 
4.1. 
Participant Inclusion Criteria ....................................................................... 85 
4.2. 
Participant Exclusion Criteria ...................................................................... 86 
4.3. 
Participant Withdrawal Criteria .................................................................... 88 
4.3.1. 
Discontinuation from Treatment ................................................... 88 
4.3.2. 
Withdrawal of Consent ................................................................. 89 
4.3.2.1. 
Further Research Maintaining Confidential 
Participant Information ................................................ 90 
4.3.3. 
Discontinuation from the Study .................................................... 90 
5. 
TREATMENT OF PARTICIPANTS ......................................................................... 92 
5.1. 
Description of Study Drug ........................................................................... 92 
5.2. 
Concomitant Medications ............................................................................ 92 
5.2.1. 
Prohibited Medications ................................................................. 93 
5.3. 
Treatment Compliance ................................................................................ 94 
5.4. 
Randomization and Blinding ....................................................................... 94 
5.4.1. 
Participant Identification ............................................................... 94 
5.4.2. 
Randomization Scheme ............................................................... 94 
5.4.3. 
Blinding and Breaking the Blind ................................................... 94 
5.4.3.1. 
Unblinding Post Analysis (31 October 2024, 
Prior to PACT) ............................................................ 95 
5.5. 
Continued Access to Study Intervention After the End of the Study ............ 96 
5.6. 
Continued Access to Study Intervention After Data Cut-off Prior to 
EoS ............................................................................................................. 97 
6. 
STUDY DRUG MATERIALS AND MANAGEMENT ................................................ 98 
6.1. 
Study Drug .................................................................................................. 98 
6.1.1. 
Niraparib ...................................................................................... 98 
6.1.2. 
Dostarlimab ................................................................................. 98 
6.2. 
Study Drug Packaging and Labeling ........................................................... 98 
6.3. 
Study Drug Storage .................................................................................... 98 
6.4. 
Study Drug Preparation .............................................................................. 99 
6.5. 
Order of Study Drug Administration ............................................................ 99 
6.5.1. 
Investigational Medicinal Products ............................................... 99 
6.5.1.1. 
Niraparib ..................................................................... 99 

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6.5.1.2. 
Dostarlimab .............................................................. 100 
6.5.2. 
Non-Investigational Medicinal Products ..................................... 100 
6.5.2.1. 
Bevacizumab ............................................................ 100 
6.5.2.2. 
Paclitaxel-Carboplatin (Cycles 1 to 6) ....................... 101 
6.6. 
Study Drug Accountability ......................................................................... 101 
6.7. 
Study Drug Handling and Disposal ........................................................... 102 
7. 
ASSESSMENT OF EFFICACY ............................................................................ 103 
7.1. 
Primary Efficacy Endpoint ......................................................................... 103 
7.2. 
Secondary Efficacy Endpoints .................................................................. 103 
7.2.1. 
Overall Survival.......................................................................... 103 
7.2.2. 
BICR determined PFS per RECIST v1.1 .................................... 104 
7.2.3. 
Health-Related Quality of Life .................................................... 104 
7.2.4. 
Time to First Subsequent Therapy ............................................. 105 
7.2.5. 
Time to Second Subsequent Therapy ........................................ 105 
7.2.6. 
Progression-Free Survival 2....................................................... 105 
7.2.7. 
Objective Response Rate .......................................................... 105 
7.2.8. 
Duration of Response ................................................................ 106 
7.2.9. 
Disease Control Rate ................................................................. 106 
7.3. 
Biomarker Endpoints ................................................................................ 106 
7.4. 
Immunogenicity Endpoints ........................................................................ 106 
7.5. 
Pharmacokinetic Endpoints ...................................................................... 106 
8. 
ASSESSMENT OF SAFETY ................................................................................ 107 
8.1. 
Safety Parameters .................................................................................... 107 
8.1.1. 
Demographic/Medical History .................................................... 107 
8.1.1.1. 
Disease History ........................................................ 107 
8.1.1.2. 
Medical and Surgical History .................................... 107 
8.1.1.3. 
Previous and Concomitant Medications .................... 107 
8.1.2. 
Vital Signs .................................................................................. 107 
8.1.3. 
Weight and Height ..................................................................... 108 
8.1.4. 
Physical Examination ................................................................. 108 
8.1.5. 
Laboratory Assessments ........................................................... 108 
8.1.5.1. 
Hematology .............................................................. 109 
8.1.5.2. 
Blood Chemistry ....................................................... 109 
8.1.5.3. 
Tumor Marker ........................................................... 110 
8.1.5.4. 
Urine Protein ............................................................ 110 
8.1.5.5. 
Drug Screen ............................................................. 110 
8.1.5.6. 
Pregnancy Screen .................................................... 110 
8.1.6. 
Hepatitis B and Hepatitis C Testing............................................ 110 
8.1.7. 
ECOG Performance Status ........................................................ 110 
8.1.8. 
Electrocardiogram ...................................................................... 110 
8.2. 
Adverse and Serious Adverse Events ....................................................... 111 
8.2.1. 
Definitions .................................................................................. 111 
8.2.1.1. 
Adverse Event .......................................................... 111 
8.2.1.2. 
Serious Adverse Event ............................................. 111 
8.2.1.3. 
Treatment-Emergent Adverse Event ........................ 112 
8.2.1.4. 
Adverse Event of Special Interest ............................. 112 
8.2.1.5. 
Overdose .................................................................. 112 
8.2.2. 
Assessment of Adverse Events ................................................. 112 
8.2.2.1. 
Severity Assessment ................................................ 112 
8.2.2.2. 
Relationship to Study Intervention ............................ 112 

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8.2.2.3. 
Expectedness ........................................................... 113 
8.2.3. 
Collection and Recording Adverse Events ................................. 113 
8.2.3.1. 
Safety Reporting During PACT ................................. 114 
8.2.4. 
Follow-Up of Adverse Events ..................................................... 114 
8.2.5. 
Reporting ................................................................................... 115 
8.2.6. 
Submission and Distribution of Serious Adverse Event 
Reports ...................................................................................... 116 
8.2.7. 
Adverse Events of Special Interest ............................................ 117 
8.2.8. 
Myelodysplastic Syndrome/Acute Myeloid Leukemia ................. 118 
8.2.9. 
Hypertension, Including Hypertensive Crisis .............................. 118 
8.2.10. 
Posterior Reversible Encephalopathy Syndrome ....................... 118 
8.2.11. 
Pregnancy ................................................................................. 118 
9. 
STATISTICS ........................................................................................................ 120 
9.1. 
Sample Size Determination ...................................................................... 120 
......................................................... 120 
......................................................... 120 
9.2. 
Analysis Populations ................................................................................. 121 
9.3. 
Demographics, Medical History, Baseline Characteristics, and 
Concomitant Medications .......................................................................... 121 
9.4. 
Efficacy Analyses ...................................................................................... 121 
9.4.1. 
Primary Efficacy Analysis ........................................................... 121 
9.4.2. 
Secondary Efficacy Analyses ..................................................... 122 
9.5. 
Safety Analyses ........................................................................................ 122 
9.6. 
Interim Analyses ....................................................................................... 122 
9.7. 
Final Analyses .......................................................................................... 123 
9.8. 
Biomarker Analysis ................................................................................... 123 
9.9. 
Immunogenicity Analysis .......................................................................... 123 
9.10. Pharmacokinetic Analysis ......................................................................... 123 
9.10.1. 
Statistical Analysis of PK Data ................................................... 123 
9.10.2. 
Exploratory Biomarker Analyses ................................................ 124 
10. DIRECT ACCESS TO SOURCE DATA/DOCUMENTS ........................................ 125 
10.1. Study Monitoring ....................................................................................... 125 
10.2. Audits and Inspections .............................................................................. 125 
10.3. Institutional Review Board (IRB)/Institutional Ethics Committee 
(IEC) ......................................................................................................... 126 
11. QUALITY CONTROL AND QUALITY ASSURANCE ............................................ 127 
12. ETHICS ................................................................................................................ 128 
12.1. Ethics Review ........................................................................................... 128 
12.2. Ethical Conduct of the Study ..................................................................... 128 
12.3. Written Informed Consent ......................................................................... 128 
13. DATA HANDLING AND RECORDKEEPING ........................................................ 129 
13.1. Inspection of Records ............................................................................... 129 
13.2. Retention of Records ................................................................................ 129 
14. PUBLICATION POLICY ....................................................................................... 129 
15. LIST OF REFERENCES ...................................................................................... 130 
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16. APPENDICES ...................................................................................................... 137 
APPENDIX 1. 
SCHEDULE OF EVENTS .......................................................... 137 
APPENDIX 2. 
PK SAMPLING SCHEDULE ...................................................... 154 
APPENDIX 3. 
CONTRACEPTIVE GUIDELINES .............................................. 156 
APPENDIX 4. 
RESPONSE EVALUATION CRITERIA IN SOLID 
TUMORS V1.1 157 
APPENDIX 5. 
REQUIRED IMAGING ............................................................... 160 
APPENDIX 6. 
EASTERN COOPERATIVE ONCOLOGY GROUP 
(ECOG) PERFORMANCE STATUS ..................................................................... 161 
APPENDIX 7. 
WORLD MEDICAL ASSOCIATION DECLARATION OF 
HELSINKI 
162 
... 163 
... 166 
... 168 
APPENDIX 11. 
ADAPTATIONS IN STUDY DESIGN ......................................... 170 
 
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LIST OF TABLES 
Table 1: 
Document History ..................................................................................... 4 
Table 2: 
Summary of Changes for Amendment 10................................................. 5 
Table 3: 
Abbreviations and Specialist Terms ....................................................... 34 
Table 4: 
Characteristics of the 5 Main Histological Subtypes of Ovarian 
Cancer ................................................................................................... 42 
Table 5: 
Progression-Free Survival in Participants with Ovarian Cancer by 
Study ...................................................................................................... 45 
Table 6: 
Progression-Free Survival in Participants with Ovarian Cancer in 
NOVA ..................................................................................................... 47 
Table 7: 
Study Treatment (Standard of Care and Investigational Therapy) 
Dosage and Mode of Administration: Arm 1 (Post-Amendment 4) .......... 67 
Table 8: 
Study Treatment (Standard of Care and Investigational Therapy) 
Dosage and Mode of Administration: Arms 2 and 3 ................................ 69 
Table 9: 
Niraparib Dose Reduction for Adverse Reactions ................................... 71 
Table 10: 
Dose Modifications for Non Hematologic Adverse Reactions ................. 72 
Table 11: 
Dose Modifications for Hematologic Adverse Reactions ......................... 72 
Table 12: 
Dostarlimab Guidelines for Immune-Related Adverse Events ................ 75 
Table 13: 
Investigational Products ......................................................................... 92 
Table 14: 
Recommended Initial Starting Dose ..................................................... 100 
Table 15: 
Timeframes for Submitting SAE, Pregnancy and Other Event 
Reports to GSK in the PACT Phase ..................................................... 116 
Table 16: 
Schedule of Events: Prior to PACT (All Ongoing Participants) .............. 138 
Table 17: 
Schedule of Events: All Study Arms ..................................................... 141 
Table 18: 
Schedule of Events for Unblinded Participants in Arm 1 who then 
Receive Niraparib Treatment in Maintenance Treatment Period .......... 149 
Table 19: 
Dostarlimab PK and Antidrug Antibodies Sparse Sampling 
Scheme: Chemotherapy and Maintenance Treatment Periods ............. 154 
Table 20: 
Niraparib PK Sparse Sampling Scheme: Maintenance Treatment 
Period .................................................................................................. 155 
Table 21: 
For Participants with Measurable Disease (i.e., Target Disease) .......... 158 

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Table 22: 
For Participants with Non-Measurable Disease (i.e., Non-Target 
Disease) ............................................................................................... 159 

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LIST OF FIGURES 
Figure 1: 
Study Design .......................................................................................... 62 
.. 170 
.. 172 
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LIST OF ABBREVIATIONS AND DEFINITIONS OF TERMS 
Table 3: 
Abbreviations and Specialist Terms  
Abbreviation or Specialist 
Term 
Explanation 
 
 
ADP 
adenosine diphosphate 
ADR 
adverse drug reaction; an adverse event where a causal 
relationship between a medicinal product and the adverse 
event is at least a reasonable possibility, i.e., the relationship 
cannot be ruled out. 
a. In the context of a clinical trial, an ADR can be serious or 
non-serious. Serious ADRs may be subject to expedited 
reporting if they are considered unexpected (see SUSAR 
definition). 
b. For marketed products, ADRs are subject to expedited 
reporting within the country where they are authorized. 
AE 
adverse event 
AESI 
adverse event of special interest 
ALT 
alanine aminotransferase 
AML 
acute myeloid leukemia 
ANC 
absolute neutrophil count 
anti-mPD-1 
anti-mouse-anti-PD-1 
anti-PD(L)-1 
anti-programmed death (ligand)-1 
anti-PD-1 
anti-programmed death-1 
AST 
aspartate aminotransferase 
AUC 
area under the concentration-time curve 
AUCss 
AUC at steady state 
AxMP 
 
 
 
 
 
 
a. Authorized 
AxMP 
 
 
 
Auxiliary Medicinal Product; medicinal products used in the 
context of a clinical trial but not as investigational medicinal 
products, such as medicinal products used for background 
treatment, challenge agents, rescue medication, or used to 
assess end-points in a clinical trial. Auxiliary medicinal 
products should not include concomitant medications, that is 
medications unrelated to the clinical trial and not relevant for 
the design of the clinical trial. 
Medicinal product authorized in accordance with Regulation 
(EC) No 726/2004, or in any Member State concerned in 
accordance with Directive 2001/83/EC, irrespective of 
changes to the labelling of the medicinal product. 
1. Safety reporting with regard to auxiliary medicinal 
products shall be made in accordance with Chapter 3 of Title 
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Abbreviation or Specialist 
Term 
Explanation 
 
b. Unauthorized 
AxMP 
IX of Directive 2001/83/EC.  
a. Medicinal product not authorized in accordance with 
Regulation (EC) No 726/2004  
1. Safety reporting for unauthorized auxiliary medicinal 
products will follow the same processes and procedures as 
SUSAR safety reporting. 
Background treatment 
Type of medicinal product administered to each of the 
clinical trial participant, regardless of randomization group, 
to treat the indication that is the object of the study. 
Background treatment is generally considered to be the 
current standard care for the particular indication. In these 
trials, the IMP is given in addition to the background 
treatment and safety efficacy are assessed. The protocol may 
require that the IMP plus the background treatment is 
compared with an active comparator or with placebo plus 
background treatment. 
BICR 
Blinded Independent Central Review 
BIW 
twice weekly 
BP 
blood pressure 
BRCA 
breast cancer susceptibility gene 
BRCAmut 
BRCA mutated 
BRCAwt 
BRCA wild-type 
BRCAwt HRRneg/not 
determined 
BRCA wild-type homologous recombinant repair negative or 
not determined 
BRCAwt HRRpos 
BRCA wild-type homologous recombinant repair positive 
CA 125 
cancer antigen 125 
CBC 
complete blood count 
CC0 
complete cytoreduction score of 0 
Challenge agents 
A product given to trial participants to produce a 
physiological response that is necessary before the 
pharmacological action of the IMP can be assessed. 
CI 
confidence interval 
Co-administered (concomitant) 
products 
A product given to clinical trial participants as required in the 
protocol as part of their standard care for a condition which is 
not the indication for which the IMP is being tested and is 
therefore not part of the objective of the study. 

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Abbreviation or Specialist 
Term 
Explanation 
Comparator 
Any product used as a reference (including placebo, 
marketed product, GSK or non-GSK) for an investigational 
product being tested in a clinical trial. This is any product 
that is being used to assess the safety, efficacy, or other 
measurable value against the test product (IMP). 
CR 
complete response 
CT 
computed tomography 
CTCAE 
Common Terminology Criteria for Adverse Events 
 
CYP 
cytochrome P450 
DCR 
disease control rate 
DLT 
dose-limiting toxicity 
DNA 
deoxyribonucleic acid 
DOR 
duration of response 
EC 
endometrial cancer 
ECG 
electrocardiogram 
ECOG 
Eastern Cooperative Oncology Group 
eCRF 
electronic case report form 
EMA 
European Medicines Agency 
EORTC-QLQ-C30 
European Organisation for Research and Treatment of 
Cancer Quality of Life Questionnaire C30 
EORTC-QLQ-OV28 
EORTC-QLQ Ovarian Cancer Module OV28 
EOS 
End of study 
EOT 
End of treatment 
EQ-5D-5L 
European Quality of Life 5-Dimension 5-Level Scale  
ESMO 
European Society for Medical Oncology 
EU 
European Union 
FDA 
Food and Drug Administration 
 
 
FIGO 
International Federation of Gynecology and Obstetrics 
FiH 
First in Human 
GCP 
Good Clinical Practice 
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Abbreviation or Specialist 
Term 
Explanation 
G-CSF 
Granulocyte-colony stimulating factor 
GLP 
Good Laboratory Practice 
GSK 
Glaxo Smith Kline 
HBV/HCV 
Hepatitis B virus/Hepatitis C virus 
HIV 
human immunodeficiency virus 
HR 
hazard ratio 
HRD 
homologous recombination deficiency 
HRDpos 
HRD positive 
HRQoL 
health-related quality of life 
HRR 
homologous recombinant repair 
HUI 
Health Utility Index 
IB 
Investigator’s Brochure 
ICF 
informed consent form 
ICH 
International Council for Harmonisation of Technical 
Requirements for Pharmaceuticals for Human Use 
ICI 
immune checkpoint inhibitor 
IDMC 
Independent data monitoring committee 
IDS 
Interval debulking surgery 
IEC 
Independent Ethics Committee 
IgG4 
immunoglobulin G4  
Investigational Product 
A pharmaceutical form of an active substance or placebo 
being tested or used as a reference in a clinical trial, 
including products already with a marketing authorization 
but used or assembled (formulated or packaged) in a way 
different from the authorized form, or when used for an 
unauthorized indication, or when used to gain further 
information about the authorized form. 
IP 
intraperitoneal  
irAE 
immune-related adverse event  
irAEI 
immune-related adverse event of interest 
IRB 
Institutional Review Board 
IV 
intravenous 
LSLV 
Last Subject Last Visit (the date of the last subject to 
complete the study[i.e., assessments as defined in the 
Schedule of Events or last dose plus, if applicable, 90 day 
AE reporting period]) 

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Abbreviation or Specialist 
Term 
Explanation 
mAb 
monoclonal antibody 
MDS 
myelodysplastic syndrome 
MDSC 
myeloid-derived suppressor cell 
MedDRA 
Medical Dictionary for Regulatory Activities 
Medicinal products used to 
assess end-points 
A product given to the participant in a Clinical Trial as a tool 
to assess a relevant clinical trial endpoint; it is not being 
tested or used as a reference in the clinical trial. 
MRI 
magnetic resonance imaging 
MSI-H 
microsatellite instability-high 
MSS 
microsatellite stable 
N/A 
not applicable 
NACT 
neoadjuvant chemotherapy 
NCCN 
National Comprehensive Cancer Network 
NCI 
National Cancer Institute 
NCI-CTCAE 
National Cancer Institute - Common Terminology Criteria 
for Adverse Events 
neg 
negative 
NIH 
National Institutes of Health 
 
NSCLC 
non-small cell lung cancer 
OC 
ovarian cancer 
ORR 
objective response rate 
OS 
overall survival 
PACT 
post-analysis continued treatment 
PARP 
poly(ADP-ribose) polymerase 
PD 
progressive disease 
PD-1 
programmed death-1 
PD-L1/PD-L2 
programmed death-ligand 1/2 
PDS 
primary debulking surgery  
PFS 
progression-free survival 
PFS2 
progression on next-line therapy 
PI 
Principal investigator 
PK 
pharmacokinetics 
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Abbreviation or Specialist 
Term 
Explanation 
PO 
oral, orally 
pos 
positive 
PP 
per-protocol 
PR 
partial response 
PRES 
posterior reversible encephalopathy syndrome  
Q21D 
every 21 days 
Q3W 
every 3 weeks 
Q6W 
every 6 weeks 
QD 
once daily 
RB 
retinoblastoma gene 
RBC 
red blood cell 
RECIST 
Response Evaluation Criteria in Solid Tumors 
Rescue medication 
Medicines identified in the protocol as those that may be 
administered to the participants when the efficacy of the IMP 
is not satisfactory, or the effect of the IMP is too great and is 
likely to cause a hazard to the patient, or to manage an 
emergency situation 
RP2D 
recommended Phase 2 dose 
SAE 
serious adverse event 
SAP 
statistical analysis plan 
SD 
stable disease 
SOC 
standard of care 
Standard of Care 
Medicine(s) for a specific indication, or a component of the 
standard care for a particular medical indication, based on 
national and/or international consensus; there is no 
regulatory significance to this term. 
1. Products/regimens considered standard of care may differ 
country to country, depending on consensus in individual 
countries 
SUSAR 
Suspected Unexpected Serious Adverse Reaction; Suspected 
Unexpected Serious Adverse Reaction; in a clinical trial, a 
serious adverse reaction that is considered unexpected, i.e., 
the nature or severity of which is not consistent with the 
reference safety information (e.g., Investigator's Brochure for 
an unapproved investigational medicinal product). All 
adverse drug reactions (ADRs) that are both serious and 
unexpected are subject to expedited reporting. 
T1DM 
type 1 diabetes mellitus 

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Abbreviation or Specialist 
Term 
Explanation 
tBRCAmut 
tumor BRCA mutation 
tBRCAwt 
tumor BRCA wild type 
TEAE 
treatment-emergent adverse event 
TFST 
time to first subsequent therapy 
TSH 
thyroid stimulating hormone 
TSST 
time to second subsequent therapy 
ULN 
upper limit of normal 
US 
United States 
VAS 
visual analogue score 
VEGF 
vascular endothelial growth factor 
WHO 
World Health Organization 
WMA 
World Medical Association 
 

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1. 
INTRODUCTION 
Niraparib is an orally available, potent, and highly selective poly (adenosine diphosphate 
[ADP]-ribose) polymerase (PARP)-1 and PARP-2 inhibitor. Niraparib was approved for 
the maintenance treatment of women with recurrent epithelial ovarian, fallopian tube, or 
primary peritoneal cancer who are in a complete response (CR) or partial response (PR) 
to platinum-based combination chemotherapy by the United States (US) Food and Drug 
Administration (FDA) on 27 March 2017 and received a Marketing Authorization in the 
European Union (EU) on 16 November 2017. 
The objective of the proposed study is to evaluate the efficacy of a adding the anti-PD-1, 
dostarlimab during both the chemotherapy and maintenance periods to the standard-of-
care (SOC) regimen consisting of platinum based- combination chemotherapy ± 
concurrent and maintenance bevacizumab plus niraparib in maintenance in participants 
with newly diagnosed Stage III or IV nonmucinous epithelial cancer of the ovary, 
fallopian tube, or primary peritoneum (collectively referred to as “ovarian cancer”). 
1.1. 
Biology of Ovarian Cancer 
Ovarian cancer is the fifth overall cause for cancer death in women, representing 5% of 
all cancer deaths in women [ACS, 2016]. It is also the deadliest of gynecologic cancers: 
in 2017, 14,080 women in the US [National Cancer Institute, 2016] and in 2018, 44,576 
women in Europe [WHO, 2018] died from ovarian cancer. 
Epithelial OC is histologically divided into five main subtypes: high grade serous (HGS), 
endometrioid, clear cell (CC), low grade serous (LGS) and mucinous OC. These subtypes 
have distinct developmental origins: HGS OC predominantly arises from the epithelium 
of the distal fallopian tubes, while CC and endometrioid OC are associated with 
endometriosis [Hollis, 2016]. Through the Cancer Genome Atlas project, researchers 
have identified key molecular aberrations in patients with high-grade serous or 
endometrioid ovarian cancer [Cancer Genome Atlas Research Network, 2011]. In 
addition, clear cell ovarian cancer appears to have breast cancer susceptibility gene 
(BRCA)-like DNA repair dysfunction [Kawahara, 2017]. Key characteristics of the 
5 main histological subtypes of ovarian cancer are presented in Table 4. 
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Table 4: 
Characteristics of the 5 Main Histological Subtypes of Ovarian 
Cancer 
 
High Grade 
Serous 
Endometrioi
d 
Clear Cell 
Mucinous 
Low 
Grade 
Approximate 
proportion of 
OC cases 
70% 
10% 
10% 
<5% 
<5% 
Overall 
prognosis 
Poor 
Favorable 
Intermediate 
Intermediate 
Intermediat
e 
Tissue of origin 
/ precursor 
lesion 
Distal 
fallopian 
epithelium 
Endometriosi
s 
Endometriosi
s 
Poorly 
defined 
Serous 
borderline 
tumor 
Intrinsic 
chemosensitivit
y 
High 
High 
Low 
Low 
Low 
Associated 
hereditary 
syndromes 
Germline 
BRCA1/2 
Lynch 
syndrome 
Lynch 
syndrome 
 
 
Typical stage at 
diagnosis 
80% 
advanced 
stage 
50% early 
stage 
60% early 
stage 
80% early 
stage 
Typically 
advanced 
stage 
Frequent 
molecular 
abnormalities 
Chromosom
e instability 
BRCA1, 
BRCA2, 
TP53, NF1, 
RB1, 
CCNE1 
amplificatio
n 
PTEN, 
PIK3CA, 
ARID1A, 
CTNNB1 
PTEN, 
PIK3CA, 
ARID1A, 
chr20q13.2, 
amplification 
KRAS, 
HER2 
amplificatio
n 
KRAS, 
BRAF 
Abbreviations: ARID1A=AT-rich interaction domain 1A gene; BRAF=rapidly accelerated fibrosarcoma-B 
gene; BRCA1/ 2=breast cancer susceptibility gene 1, 2 ; CCNE1 amplification=cyclin E gene amplification; 
CTNNB1=catenin beta 1 (human) gene; HER2 amplification=human epidermal growth factor receptor 2 
amplification; KRAS=Kirsten rat sarcoma oncogene; NF1=neurofibromatosis type 1; OC=ovarian cancer; 
PIK3CA=phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha; PTEN=phosphatase and 
tensin homolog gene; RB1=retinoblastoma gene; TP53=tumor protein gene.  
Source: [Hollis, 2016].  
Besides the malignant epithelial cell itself, the tumor microenvironment in ovarian cancer 
offers additional opportunities to improve patient outcomes from ovarian cancer. 
Angiogenesis is essential for both tumor growth and metastases, making it one of the 
hallmarks of cancer and an actionable target for drug development [Yang, 2020]. The 
activity of bevacizumab is established in the treatment of newly diagnosed ovarian 
cancer, platinum sensitivity recurrent ovarian cancer, and platinum resistant ovarian 
cancer [Aghajanian, 2012; Pujade-Lauraine, 2014].  

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Immune cells represent a critical component of the tumor microenvironment [Yang, 
2020] The presence of intratumoral T-cells in newly diagnosed ovarian cancer patient is 
associated with improved progression-free survival (PFS) and overall survival (OS) in 
patients [Zhang, 2003]. Consistent with this, it has been reported that BRCA deficient 
tumors are associated with an immunoreactive molecular subtype characterized by 
intense intratumoral T-cell infiltration in high-grade serous ovarian cancer patients. 
Programmed cell death-ligand (PD-L1) expression in tumors results in T-cell 
inactivation/anergy. Survival outcomes are negatively impacted in tumors with high 
PD-L1 expression regardless of tumor stage, histologic type, residual tumor burden, and 
chemotherapy [Hamanishi, 2007]. Preliminary efficacy rates for single-agent PD-1 or 
PD-L1 inhibitors range from 5.9% to 15% in unselected recurrent ovarian cancer patients, 
in clinical studies that include patients with platinum-sensitive disease [Hamanishi, 2015; 
Varga, 2015; Disis, 2016; Infante, 2016]. These data support the incorporation of 
dostarlimab and niraparib into the first-line treatment of advanced ovarian cancer. 
1.2. 
First-Line Chemotherapy for Advanced Ovarian Cancer 
Most women with ovarian cancer present with Stage III or IV disease, contributing to its 
high mortality rate. In spite of its widespread nature, debulking surgery still plays a major 
role in the treatment of newly diagnosed ovarian cancer patients. Five-year survival rates 
are significantly improved in those patients who have undergone optimally debulked 
disease (i.e., residual tumor nodules <1 cm) compared to patients who have undergone 
suboptimal debulking (i.e., residual tumor nodules ≥1 cm) (47% and 35%, respectively) 
[Chi, 2009]. Overall, depending upon stage and post-operative tumor burden, 5-year 
survival rates for advanced ovarian cancer patients following surgery and platinum-based 
combination therapy in advanced ovarian cancer patients have remained relatively stable 
at 26% to 42% [Torre, 2018]. 
A pivotal study conducted by European Organization for Research and Treatment of 
Cancer (EORTC) Investigators compared primary debulking surgery (PDS) followed by 
at least 6 cycles of platinum-based combination chemotherapy to 3 cycles of neoadjuvant 
chemotherapy (NACT), plus interval debulking surgery (IDS) and 3 cycles of 
chemotherapy post-operatively in patients with Stage IIIC or IV ovarian cancer. NACT 
patients had noninferior outcomes to PDS patients based upon the primary study endpoint 
of OS (median survival: 30 months versus 29 months) and PFS (median PFS of 
12 months in both arms). Furthermore, the use of NACT was associated with lower rates 
of post-operative morbidity (e.g., hemorrhage, infection, venous complications) and 
mortality (0.7 versus 2.5%). This study also demonstrated that the most favorable 
outcomes were observed in patients with complete macroscopic resection (median 
survival: 39 months for NACT patients and 45 months for PDS patients) [Vergote, 2010]. 
Based upon these results, the use of NACT is increasingly administered in patients with 
large volume Stage IIIC/IV disease.  
For patients with inoperable disease, sub-optimally debulked disease following PDS or 
the presence of significant upper abdominal disease (e.g., disease present on the surface 
of the liver, diaphragmatic peritoneum, stomach, pancreas, and large volume ascites 
which indicate a high likelihood of unresectable disease or residual disease after surgery), 
intravenous (IV) paclitaxel in combination with carboplatin is the SOC based upon a 

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superior toxicity profile and comparable efficacy when compared to IV paclitaxel in 
combination with cisplatin [Ozols, 2003; du Bois, 2003]. Per European Society for 
Medical Oncology (ESMO) guidelines, paclitaxel 175 mg/m2 and carboplatin at an area 
under the concentration-time curve (AUC) of 5 to 6 mg/mL/min administered every 3 
weeks (Q3W) have been the clinical and research SOC in first-line ovarian cancer 
patients for more than 15 years [Ledermann, 2013]. For patients with optimally 
cytoreduced ovarian cancer following PDS, intraperitoneal (IP) therapy is an option. 
However, this type of therapy remains controversial [Walker, 2016].  
Dose dense strategies, in which either carboplatin or the combination of carboplatin and 
paclitaxel was administered on a weekly schedule with or without bevacizumab, have 
yielded conflicting results [Katsumata, 2013; Chan, 2016; Pignata, 2014]. Bevacizumab 
has been evaluated in multiple clinical studies, including in 1,873 patients with newly 
diagnosed, Stage III (incompletely resected) or Stage IV epithelial ovarian cancer who 
had undergone debulking surgery as part of a Phase 3 study (GOG218) [Burger, 2011]. 
Patients receiving bevacizumab administered concurrently with chemotherapy and as a 
maintenance treatment showed statistically significant improvement in PFS compared to 
placebo (18.2 months vs 12.0 months; hazard ratio [HR], 0.62; p<0.0001) [AVASTIN®, 
2016].  
Bevacizumab was also evaluated in 1,528 patients with ovarian cancer, regardless of 
International Federation of Gynecology and Obstetrics (FIGO) stage as part of a Phase 3 
study (ICON7). Patients receiving bevacizumab administered concurrently with 
chemotherapy and as a maintenance treatment showed statistically significant 
improvement in PFS compared to chemotherapy alone (19.0 months vs 17.3 months; HR, 
0.81; p=0.004), with maximum improvement compared to chemotherapy alone at 12 
months (15.1%; 95% confidence interval [CI], 10.7-19.5). The improvement was even 
more pronounced in patients at high risk of progression (i.e., FIGO Stage IV or FIGO 
Stage III and >1.0 cm of residual disease after debulking surgery; 15.9 months vs 10.5 
months; HR, 0.68; p≤0.001) [Perren, 2011]. 
The National Comprehensive Cancer Network (NCCN) provides Level 2A 
recommendation for Q3W paclitaxel-carboplatin ± bevacizumab, dose dense weekly 
carboplatin with Q3W paclitaxel, dose dense weekly carboplatin and paclitaxel, and 
systemic and IP paclitaxel with systemic cisplatin in optimally debulked patients, ESMO 
guidelines recommend Q3W paclitaxel-carboplatin [Ledermann, 2013]. Bevacizumab, in 
combination with carboplatin and paclitaxel, followed by bevacizumab maintenance as a 
single agent, is approved by the FDA and European Medicines Agency (EMA) for the 
treatment of patients with Stage III or IV epithelial, ovarian, fallopian tube, or primary 
peritoneal cancer following initial surgical resection.  
The introduction of PARP inhibitors into the first-line maintenance setting is warranted 
based on experience in platinum sensitive recurrent ovarian cancer. In a pivotal 
double-blind placebo-controlled study of niraparib maintenance in patients in CR or PR 
to their last platinum therapy, PFS was significantly improved in germline BRCA mutated 
(gBRCAmut) patients as well as non-gBRCAmut patients [Mirza, 2016]. Significant 
improvement in PFS was also reported in patients with BRCA mutated (BRCAmut) 
ovarian cancer treated with olaparib or all-comers treated with rucaparib in the 

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maintenance setting [Pujade-Lauraine, 2017; Coleman, 2017]. Based on the results of 
these pivotal studies (NCT01844986, NCT02477644, and NCT02655016), niraparib and 
olaparib are currently being studied in the Phase 3 setting as maintenance therapy 
following first-line platinum-based combination therapy in participants with homologous 
recombination deficiency (HRD) positive and negative tumors (niraparib), or participants 
with gBRCAmut ovarian cancer (olaparib), or added to continuation bevacizumab therapy 
in all comers (olaparib) [González-Martín, 2019; Moore, 2018; Ray-Coquard, 2019b].  
In 2018, the Phase 3 study investigating olaparib monotherapy maintenance versus 
placebo following frontline platinum-based chemotherapy (SOLO-1) reported that PARP 
inhibitor maintenance provided significant clinical benefits. Olaparib demonstrated a PFS 
HR of 0.30 (95% CI: 0.23-0.41, p<0.001) in 391 randomized participants with advanced 
ovarian cancer and a BRCA1/2 mutation. The median progression free survival (mPFS) at 
41 months was 49.9 months for olaparib versus 13.8 months for placebo (data maturity, 
51%) [Moore, 2018]. Olaparib received approval in the US and EU in December 2018 
and June 2019, respectively. 
In 2019, two Phase 3 studies demonstrated the efficacy of PARP inhibitor maintenance 
therapy in all participants regardless of BRCA status in newly diagnosed advanced 
ovarian cancer. The Phase 3 PRIMA study demonstrated a PFS HR of 0.62 (95% CI: 0.50 
to 0.76, p<0.001) in participants who received niraparib as compared to placebo in 
participants who responded to first-line platinum based chemotherapy and this regimen 
was approved in the US on 29 April 2020 and in EU on 27 October 2020 [González-
Martín, 2019]. A summary of PFS in participants with ovarian cancer by study is 
presented in Table 5. 
Table 5: 
Progression-Free Survival in Participants with Ovarian Cancer by 
Study 
Study 
PRIMA1 
SOLO-12 
PAOLA3 
Data  
HR (95% CI) 
HR (95% CI) 
HR (95% CI) 
Overall 
0.62 (0.50-0.76) 
NA 
0.59 (0.49-0.72) 
HR-deficient (all) 
 
BRCAmut 
 
BCRAwt 
0.43 (0.31-0.59) 
 
0.40 (0.27-0.62) 
 
0.50 (0.31-0.83) 
NA 
 
0.30 (0.23-0.41) 
 
NA 
0.33 (0.25-0.45) 
 
0.31 (0.20-0.47) 
 
0.43 (0.28-0.66) 
HR-proficient 
0.68 (0.49-0.94) 
NA 
1.00 (0.75-1.35) 
Abbreviations: BRCAmut=mutation in the BRCA gene; BRCAwt=wild-type BRCA gene; CI=confidence 
interval; HR-deficient=homologous recombination deficient; HR=hazard ratio; HR-proficient=homologous 
recombination proficient; NA=not applicable. 
1[González-Martín, 2019]; 2[Moore, 2018]; 3[Ray-Coquard, 2019a]. 

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Key findings presented at ESMO, 27 September 2019 from the PAOLA-1 study, a 
randomized Phase 3 study of olaparib maintenance therapy or placebo added to 
bevacizumab maintenance treatment following first-line platinum therapy for Stage III/IV 
ovarian cancer, showed an improved PFS in participants who receive bevacizumab plus 
olaparib, HR 0.59 (95% CI: 0.49-0.72; p<0.0001) [Ray-Coquard, 2019b]. Based on 
results from PAOLA-1, olaparib in combination with bevacizumab in HR-deficient 
participants received approval in the US and EU in the frontline maintenance setting.  
The FIRST study design will enable Investigators to provide participants with the current 
SOC for advanced ovarian cancer should it change during study conduct as results are 
anticipated from pivotal studies of first-line PARP inhibitor maintenance therapy that 
may lead to the incorporation of PARP inhibitors into first-line treatment of advanced 
ovarian cancer.  
1.3. 
Background of Niraparib 
Niraparib is an orally available, potent, and highly selective PARP1 and PARP2 inhibitor 
that is approved for the maintenance treatment of adult patients with advanced epithelial 
ovarian, fallopian tube, or primary peritoneal cancer who are in a complete or partial 
response to first-line platinum-based chemotherapy, and additionally for adult patients 
with deleterious or suspected deleterious germline BRCA-mutated recurrent epithelial 
ovarian, fallopian tube, or primary peritoneal cancer who are in a complete or partial 
response to platinum-based chemotherapy. The inhibition of PARP by niraparib has been 
confirmed by a battery of in vitro and in vivo nonclinical studies using models that are 
HRD through silencing or mutation of BRCA1 or BRCA2. Notably, PARP inhibition in 
tumor tissue is greater and more durable than PARP inhibition in nontumor tissue from 
the same animals. 
The initial niraparib study, PN001, was a Phase 1 multiple ascending dose study. In this 
study, 300-mg niraparib administered orally once daily (QD) was the maximum tolerated 
dose of niraparib monotherapy, in consideration of clinical, pharmacokinetic (PK), and 
pharmacodynamic data. The clinical activity of niraparib was observed among 
participants with various advanced and refractory tumor types, particularly among those 
with ovarian or prostate cancer with and without BRCA mutations. 
The clinical efficacy of niraparib was demonstrated in a randomized, double-blind, 
placebo-controlled Phase 3 trial (ENGOT-OV16/NOVA) [Mirza, 2016]. To assess the 
impact of tumor genotype upon the efficacy of niraparib, participants were analyzed by 
subpopulation: gBRCAmut bearing versus those with high-grade serous histology 
non-gBRCAmut. Participants in the non-gBRCAmut subpopulation were further 
subdivided by tumor HRD status (positive or negative). In this study, PFS was 
significantly longer for participants who received niraparib compared to those who 
received placebo regardless of gBRCAmut status. Median PFS was 21.0 months for 
gBRCAmut participants receiving niraparib versus 5.5 months for those receiving placebo 
(Table 6).  

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Participants without gBRCA mutations also benefitted from niraparib therapy (median 
PFS: 9.3 months, niraparib; 3.9 months, placebo) regardless of tumor HRD status. 
Progression-free survival was also significantly longer for participants receiving niraparib 
than for those treated with placebo in the HRD positive (HRDpos) subgroup of the 
non-gBRCAmut subpopulation (median PFS: 12.9 months, niraparib; 3.8 months, 
placebo). There was no evidence for the detrimental impact of niraparib treatment on OS. 
Importantly, niraparib dose reduction had no impact on PFS outcomes. 
Table 6: 
Progression-Free Survival in Participants with Ovarian Cancer in 
NOVA 
gBRCAmut 
non-gBRCAmut 
(regardless of HRD 
status) 
non-gBRCAmut + 
HRDpos 
Niraparib 
(N=138) 
Placebo 
(N=65) 
Niraparib 
(N=234) 
Placebo 
(N=116) 
Niraparib 
(N=106) 
Placebo 
(N=56) 
Median PFSa 
(95% CI) 
21.0 
(12.9, 
NR) 
5.5 
(3.8, 7.2) 
9.3 
(7.2, 11.2) 
3.9 
(3.7, 5.5) 
12.9 
(8.1, 15.9) 
3.8 
(3.5, 5.7) 
p value 
<0.0001 
<0.0001 
<0.0001 
Hazard Ratiob  
(95% CI) 
0.27 
(0.173, 0.410) 
0.45 
(0.338, 0.607) 
0.38 
(0.243, 0.586) 
Abbreviations: CI=confidence interval; gBRCAmut=germline breast cancer susceptibility gene mutated; 
HRD=homologous recombination deficient; HRDpos=HRD positive; N=number of participants included in 
subpopulation; PFS=progression-free survival. 
aProgression-free survival is defined as the time in months from the date of randomization to progression or 
death. 
bHazard Ratio=Niraparib:Placebo.  
Source: [Mirza, 2016] 
Secondary endpoints (chemotherapy-free interval [CFI], time to first subsequent therapy 
[TFST], time to second subsequent therapy [TSST], and time to progression on next-line 
therapy [PFS2]) demonstrated a persistent treatment effect for participants receiving 
niraparib in the gBRCAmut and overall, non-gBRCAmut subpopulations. No detrimental 
impact of niraparib treatment on OS was observed at the time of the primary analysis. 
The results were supported by sensitivity analyses that were consistent with the primary 
efficacy analyses. Importantly, dose reductions had no impact on PFS. Patient-reported 
outcome (PRO) data measuring quality-of-life (QoL) parameters were similar for 
participants in the niraparib and placebo treatment arms in both subpopulations. 
Cumulatively, these data provide compelling evidence that niraparib does not diminish 
responsiveness to subsequent therapy and that the niraparib treatment effect persists 
[Mirza, 2016]. Accordingly, in 2017, a recommendation to consider niraparib 
maintenance therapy for this indication and population was added to the NCCN 
guidelines.  
In a cumulative safety analysis of 1,625 niraparib-treated participants, the most 
commonly reported treatment-emergent adverse events (TEAEs) (in at least 10%) were 
primarily gastrointestinal (nausea, vomiting, constipation, and abdominal pain), 

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constitutional (fatigue and decreased appetite), hematological (anemia, 
thrombocytopenia, and decreased platelet count), neurological (headache), or psychiatric 
(insomnia) in nature. While events were generally considered related to study drug, most 
were mild (Grade 1) to moderate (Grade 2) in severity. Grade 3 or higher TEAEs 
consisted primarily of hematological events (anemia, neutropenia, and thrombocytopenia) 
and investigations (platelet count decreased, neutrophil count decreased, and white blood 
cell count decreased), followed by gastrointestinal events (nausea, vomiting, and 
abdominal pain). Dose modification has been an important component in the 
management of adverse events (AEs), and lower doses do not appear to compromise the 
efficacy of niraparib in terms of PFS. A comprehensive review of the safety profile of 
niraparib is presented in the current Investigator’s Brochure [GSK document Number 
RPS-CLIN-108400]. Recommendations for dose modification strategies to be used 
during this study are provided in Section 3.4.1. 
1.3.1. 
Baseline Body Weight and Platelet Count as Predictors of 
Thrombocytopenia 
Additional exploratory analysis of the NOVA study data identified that participants with 
a baseline body weight <77 kg or with a baseline platelet count <150,000/μL before the 
initiation of niraparib treatment have a higher incidence of Grade 3 or 4 
thrombocytopenia and other AEs from niraparib treatment. A dose-response relationship 
between AEs and dose was also observed for most of the commonly reported Grade 3 or 
4 events, with the highest incidence at the 300 mg dose level. The incidence of these 
Grade 3 or 4 events was lower at the 200 mg dose level.  
The dose modification approach employed in NOVA allowed participants to reach their 
optimal individual dose after the first 3 cycles. Overall, dose interruptions for any reason 
were instituted for 80% of participants on niraparib; 72% underwent a dose reduction. 
Dose reductions tended to occur early, and most participants reached their individual 
adjusted dose level by Month 4 of treatment.  
A PFS analysis from the NOVA study by dose at Month 4 demonstrated that, once the 
participants reach their optimal individualized dose, the efficacy was not compromised. 
Therefore, a lower starting dose will assist in reducing the incidence of Grade 3/4 
thrombocytopenia in these subgroups of participants without a decrement in efficacy. 
Further, despite the intent to deliver a starting dose of 300 mg, the median daily dose 
taken within the first 2 months (where most dose reductions and interruptions occurred) 
was only 207 mg for participants with baseline body weight <77 kg or baseline platelet 
count <150,000/μL compared with a median of 295 mg for participants with baseline 
body weight ≥77 kg and baseline platelet count ≥150,000/μL. Therefore, the efficacy in 
NOVA was achieved with these participants receiving a true starting dose consistent with 
a 200-mg starting dose.  
The safety data from 2 niraparib studies, QUADRA and TOPACIO, were also evaluated. 
In the QUADRA study, a lower (13.6%) incidence of Grade 3 or 4 thrombocytopenia 
during the first cycle was observed in participants with a baseline body weight ≥77 kg 
and with baseline platelet count ≥150,000/μL as compared to 30.2% incidence in 
participants with a baseline body weight <77 kg or with a platelet count <150,000/μL.  

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The Phase 2 portion of the TOPACIO study included 107 participants treated at a starting 
dose of niraparib of 200 mg in combination with pembrolizumab 200 mg in participants 
with advanced triple-negative breast cancer or platinum-resistant ovarian cancer. This 
study represented the largest dataset available with this proactively defined 200 mg 
starting dose. The lower starting dose in this study led to a lower incidence of Grade 3/4 
thrombocytopenia in participants with the baseline characteristics of body weight <77 kg 
or platelet counts <150,000/μL (14.5%) than in the NOVA (34.6%) or QUADRA 
(30.2%) studies, which utilized the 300-mg starting dose.  
For the NOVA study, participants with a baseline body weight <77 kg or a baseline 
platelet count <150,000/μL in effect received an average daily dose approximating 200 
mg (median=207 mg) due to dose interruption and reduction. It was found the use of a 
200-mg niraparib starting dose led to a lower incidence of Grade 3/4 thrombocytopenia 
events without compromising efficacy. Results from the PRIMA trial confirmed that an 
individualized starting dose of 200 mg in participants with body weight <77 kg or platelet 
count <150,000/μL and 300 mg for all other participants does not compromise efficacy. 
Thereafter, on 29 April 2020, the FDA approved niraparib for first-line maintenance of 
advanced ovarian cancer with a recommended niraparib dose (200 mg or 300 mg) based 
on body weight or platelet count. This dosing posology is reflected in the USPI for the 
frontline setting. 
1.4. 
Background of Dostarlimab 
Dostarlimab is a 
 
 
 
 
 
 
 
 
 
 
Dostarlimab has been evaluated in 4 ongoing first-in-human (FiH) Phase 1 studies of 
dostarlimab monotherapy and combination therapies to evaluate the safety and 
tolerability, PK, pharmacodynamics, and clinical activity of dostarlimab in participants 
with advanced solid tumors. The clinical experience with dostarlimab is discussed in 
Section 1.4.2 and in the dostarlimab IB [GSK document Number RPS-CLIN-106356].  
1.4.1. 
Nonclinical Experience 
Nonclinical pharmacology and toxicology studies with toxicokinetics have been 
conducted to support the dostarlimab clinical development. The nonclinical toxicology 
studies were designed and conducted in accordance with International Council for 
Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) 
Guideline S6 (R1) Preclinical Safety Evaluation of Biotechnology-Derived 
Pharmaceuticals, and ICH Guideline S9 Nonclinical Evaluation on Anticancer 
Pharmaceuticals [ICH S6 (R1), 2011; ICH S7A, 2001; ICH S9, 2009]. The studies are 
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intended to characterize the potential hazards, identify laboratory markers for any toxicity 
and to estimate the safety margins that exist to allow the safe progression of human 
clinical trials with dostarlimab. All studies were conducted to high scientific standards 
according to the established procedures and standard operating procedures of the 
performing laboratories. 
For in vivo toxicology studies, cynomolgus monkey was selected as the relevant species 
to evaluate dostarlimab toxicity. The selection was based on DNA homology of PD-1 
extracellular domains of different species, cross-species PD-1 receptor binding affinity 
peripheral blood mononuclear cell binding of dostarlimab, and receptor occupancy of 
dostarlimab. 
Nonclinical toxicology studies comprise a single-dose and a 4-week repeat-dose study 
with a 4-week recovery period in cynomolgus monkeys. Additional studies consist of 
tissue cross reactivity studies in both normal human and cynomolgus monkey tissues. All 
these studies (with the exception of the single-dose study in monkeys and the initial tissue 
cross reactivity study in normal human tissues) were conducted in compliance with the 
Organisation for Economic Co-operation and Development (OECD) Principles of Good 
Laboratory Practice (GLP) (as revised in 1997) [Organisation for Economic Co-operation 
and Development, 1998]. In addition, TESARO is conducting a 3-month GLP toxicology 
study to support further development of dostarlimab and marketing authorization. 
Safety pharmacology endpoints assessing major organ system function covering 
cardiovascular, respiratory and nervous systems were evaluated as part of the 4-week 
repeat-dose toxicology study in cynomolgus monkeys. The administration of dostarlimab 
as a weekly IV dose for 4 weeks (5 doses total) to cynomolgus monkeys at dose levels of 
up to 100 mg/kg did not result in any dostarlimab-related effects on the safety 
pharmacology parameters evaluated, including electrocardiography, blood pressure (BP), 
respiration, and neurological examinations. 
1.4.2. 
Clinical Experience 
Up-to-date clinical data on niraparib and dostarlimab are discussed in detail in the most 
current version of the respective Investigator’s Brochures, niraparib Investigator’s 
Brochure [GSK document Number RPS-CLIN-108400] and dostarlimab Investigator’s 
Brochure [GSK document Number RPS-CLIN-106356]), including all risks of niraparib 
and dostarlimab.  
As of 20 April 2024, there are 21 ongoing studies with dostarlimab (19 in adults and 2 in 
pediatrics): 7 Phase 1 studies, 2 Phase 1/2 studies, 7 Phase 2 studies, 1 Phase 2/3 study, 
and 4 Phase 3 studies. Four Phase 1 studies with dostarlimab monotherapy (Study 
213346, GARNET, or Study 4010-01-001) and dostarlimab in combination with other 
therapies (Study 213348, AMBER or Study 4020-01-001, Study 213351, IOLite or 
Study 3000-01-002, and Study 213349, CITRINO or Study 4040-01-001; completed) in 
participants with advanced or metastatic cancer and 3 Phase 2 studies with dostarlimab in 
combination with other therapies in participants with locally advanced and metastatic 
squamous NSCLC (Study 213352, JASPER or Study 3000-02-001; completed), with 
relapsed ovarian cancer (Study 213357, OPAL or Study 3000-02-005; ongoing), or with 
advanced, relapsed, ovarian cancer (Study 213353, MOONSTONE or Study 3000-02-

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006; completed) provided additional safety data. Two double-blind Phase 3 studies with 
dostarlimab combination therapy are ongoing (this study and Study 213361, RUBY or 
Study 4010-03-001) and, therefore, were not included in the evaluation of safety in the 
safety population.  
1.4.2.1. 
Dostarlimab Monotherapy 
GARNET (Study 4010-01-001) is an ongoing, FiH Phase 1 study of dostarlimab to 
evaluate the safety and tolerability, PK, pharmacodynamics, and clinical activity of 
dostarlimab in participants with recurrent or advanced solid tumors. A total of 
21 participants were dosed in the dose escalation phase of the study (Part 1). Dose 
escalation continued to a maximally administered dose of 10 mg/kg every 2 weeks and a 
maximum tolerated dose was not identified. No dose limiting toxicities (DLTs) were 
observed. In Part 2A of the study, the safety and tolerability of dostarlimab was evaluated 
at 2 fixed dosing schedules: 500 mg Q3W and 1,000 mg every 6 weeks (Q6W). No DLTs 
were observed in Part 2A. The recommended Phase 2 dose (RP2D) regimen was 
determined to be 500 mg Q3W for 4 cycles followed by 1,000 mg Q6W for all cycles 
thereafter, which is being evaluated in expansion cohorts for microsatellite instability-
high (MSI-H) and microsatellite stable (MSS) endometrial cancer (EC), non-small cell 
lung cancer (NSCLC), and non-endometrial MSI H or polymerase ε-mutated cancer in 
Part 2B of study.  
As of 21 January 2020, 535 participants with heavily pretreated advanced solid tumors 
have been treated with dostarlimab in GARNET. The majority of these participants 
(98.5%) reported at least 1 TEAE, with events of fatigue, nausea, anemia, and diarrhea 
being the most frequently reported (>20%). The majority of the Grade ≥3 events occurred 
in 2% of participants or less each, with the exception of anemia (8.6%), dyspnea (3.7%), 
abdominal pain (3.4%), fatigue (2.8%), hyponatremia (2.8%), and pulmonary embolism 
(2.4%). Serious AEs occurred in 38.3% of participants, for which 7.3% of these 
participants was considered study drug related. Forty-eight participants (9.0%) had an AE 
leading to study drug discontinuation. Twenty-five participants (4.7%) had a TEAE 
leading to study drug discontinuation that was considered study drug related. 
Sixteen participants (3.0%) had a TEAE leading to death. None of the AEs leading to 
death were considered related to the study drug. 
In an updated presentation of the GARNET study at Society of Gynecologic Oncology 
(SGO) (March 2019), 41 participants with MSI-H EC and 79 participants with MSS EC 
have had at least 1 tumor assessment. Among the 41 participants with MSI-H EC, the 
objective response rate (ORR) was 48.8% and consisted of 2 participants with CRs 
(4.9%) and 18 participants with PRs (43.9). The disease control rate (DCR) among these 
participants was 63.4%, and at the time of data cutoff, responses were ongoing in 85% of 
responders. For 79 participants with MSS EC, the ORR was 20.3% including 4 
participants with CRs (5.1%) and 12 participants with PRs (15.2%). The DCR among 
these participants was 46.8%, and responses were ongoing in 81.3% of responders. 
Dostarlimab demonstrated clinically meaningful response rates regardless of MSI status, 
with an overall ORR of 30% (49% in the MSI-H cohort and 20% in the MSS cohort).  

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1.4.2.2. 
Investigational Therapeutic Combinations with Dostarlimab 
In addition to the GARNET dostarlimab monotherapy, 3 additional studies involving 
dostarlimab and other therapeutic agents are being evaluated.  
Study 213348, AMBER or Study 4020-01-001 is an open-label, FiH Phase 1 study of 
, that is being 
conducted in 2 parts in patients with advanced solid tumors. In Part 1C of this study, 
dostarlimab will be administered in combination with cobolimab. In Part 1D: dostarlimab 
will be administered in combination with cobolimab and encelimab. In Part 1E 
dostarlimab will be administered in combination with cobolimab. In Part 1F dostarlimab 
will be administered in combination with cobolimab and docetaxel. 
Study 213351, IOLite or Study 3000-01-002 is an open-label, Phase 1b study of 
dostarlimab that is being conducted in 9 parts in participants with advanced or metastatic 
cancer. The study is evaluating DLTs, safety, and tolerability of dostarlimab in 
combination with niraparib with or without bevacizumab or carboplatin and paclitaxel 
with or without bevacizumab or carboplatin and pemetrexed with or without cobolimab 
or carboplatin and nab-paclitaxel with or without cobolimab or cobolimab and 
carboplatin and paclitaxel.  
Study 213349, CITRINO or Study 4040-01-001 was an open-label, FiH Phase 1 study of 
, that was conducted 
in 2 parts in participants with advanced solid tumors. In Part 1C, dostarlimab was 
administered in combination with encelimab to establish the RP2D regimen for this study 
drug combination. In Part 2 of the study, the efficacy of encelimab with or without 
dostarlimab was evaluated in participants with advanced solid tumors. 
As of 20 April 2024, an estimated 3657 participants (870 in monotherapy; 2787 in 
combination with other agents) have been exposed to dostarlimab in sponsored 
interventional studies. Overall, the safety profile of dostarlimab has been consistent with 
that of other PD-1 and PD-L1 inhibitors. Given the encouraging clinical activity in 
heavily pretreated participants with diverse tumor types and the manageable safety 
profile of dostarlimab, the benefit-risk profile for dostarlimab as a treatment for 
participants with advanced cancers appears positive. 
Please refer to the most current version of the dostarlimab IB [GSK document Number 
RPS-CLIN-106356] for more information. 
1.5. 
Combination Therapies Proposed in the Current Trial 
1.5.1. 
Addition of PD-1 Inhibitor to Chemotherapy 
1.5.1.1. 
Nonclinical 
There is accumulating evidence that in addition to direct cytostatic and cytotoxic effects, 
the mechanisms of action of conventional chemotherapies may also involve activation of 
tumor-targeted immune responses, including increasing the immunogenicity of cancer 
cells and reducing immunosuppression of tumors [Kroemer, 2013; Hato, 2014]. In 
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nonclinical models, platinum-based agents have been suggested to increase direct 
cytostatic-mediated activation of T-cells by several mechanisms, including down-
regulation of PD-L2, increased adenosine triphosphate, and increased high mobility 
group protein box-1 release from dying cells [Hato, 2014]. Several immune-stimulatory 
effects of paclitaxel on the immune system have also been reported; among these are the 
induction of endoplasmic reticulum stress, which can lead to calreticulin exposure and 
dendritic cell stimulation [Senovilla, 2012], depletion of myeloid-derived suppressor cells 
[Liechtenstein, 2014; Sevko, 2013], and boosting of T-cell priming [Pfannenstiel, 2010]. 
These data suggest that chemotherapy agents may modulate the tumor microenvironment, 
an effect that could be enhanced by the addition of immune checkpoint inhibitors (ICIs), 
such as those targeting PD-1 or PD-L1. 
1.5.1.2. 
Clinical 
Carboplatin-paclitaxel in combination with anti-PD-1 antibody agents has been studied 
clinically. In several studies, in participants with advanced NSCLC, the combination has 
been well tolerated and has shown encouraging antitumor activity. Nivolumab at 5 or 
10 mg/kg and carboplatin-paclitaxel combination treatment was evaluated in the 
CheckMate 012 study, a Phase 1, multicohort study exploring the safety and efficacy of 
nivolumab monotherapy and nivolumab in combination with current standard therapies in 
first-line advanced NSCLC. The safety profile of combination treatment was found to be 
manageable, and the clinical activity of nivolumab 5 mg/kg and carboplatin-paclitaxel 
combination treatment showed evidence of efficacy [Rizvi, 2016]. Carboplatin-paclitaxel 
was administered in combination with the anti-PD-1 antibody pembrolizumab in the 
KEYNOTE-021 study in participants with advanced non-squamous NSCLC. The study 
concluded that pembrolizumab and carboplatin-paclitaxel combination treatment may be 
an effective and tolerable first-line treatment option for participants with advanced non-
squamous NSCLC [Langer, 2016].  
Dostarlimab was evaluated at
 in combination with paclitaxel 175 
mg/m2 and carboplatin AUC 5-6 in advanced cancer participants in Part B of Study 
213351, IOLite or Study 3000-01-002. The safety of paclitaxel, carboplatin and 
dostarlimab in advanced cancer participants was established in Part B of this study.  
1.5.2. 
Addition of anti-PD-1 and PD-L1 Inhibitor to PARP Inhibitor 
1.5.2.1. 
Nonclinical 
It has been demonstrated that PARP inhibitor treatment is able to increase lymphocyte 
infiltration and activation in mouse tumor models, turning “cold” tumors into “hot” 
tumors, which are more likely to respond to anti-PD-1 therapies [Huang, 2015]. The 
rationale behind this finding is that PARP inhibition leads to accumulation of DNA 
damage and cytoplasmic DNA, which stimulates the stimulator of interferon genes 
(STING)-dependent immune response [Wang, 2019] and results in activation of type I 
interferon pathway. Indeed, multiple molecular mechanisms have been reported 
indicating that intrinsic DNA repair deficiency is also able to trigger an innate immune 
response through the accumulation of cytosolic DNA and activation of the stimulator of 
interferon gene pathway [Harding, 2017]. 
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Type I interferon has been reported to activate antitumor immunity through multiple 
mechanisms, including stimulation of innate and adaptive cytotoxic lymphocytes, 
downregulation of suppressive immune cells such as regulatory T-cells and myeloid-
derived suppressor cells, and direct inhibition of tumor cell proliferation. The type I 
interferon-mediated activation of immune cells is mediated by upregulation of tumor 
antigen expression; activation of antigen-presenting dendritic cells; and stimulation of the 
release of secondary mediators such as chemokines, cytokines, and interleukins [Parker, 
2016]. Recently, PARP inhibitors have been shown to elevate PD-L1 expression [Jiao, 
2017]. This finding suggests that the immunomodulatory effects of PARP inhibitors 
could be muted by the expression of PD-L1. Thus, blocking anti-PD-1 or PD-L1 may 
enhance the ability of niraparib to induce durable responses. 
The efficacy and tolerability of niraparib in combination with anti-PD-1 therapy was 
evaluated in several immune-competent nonclinical models and the combination was well 
tolerated in these studies. The combination was first tested in a HRd ovarian cancer 
mouse model derived from BRCA null genetic background [Xing, 2006], as PARP 
inhibition was previously shown to increase immune cell infiltration in BRCA-deficient 
models [Huang, 2015]. In a study of an ovarian carcinoma mouse model niraparib 
(50 mg/kg orally [PO] QD) and anti-mouse anti-PD-1 (anti-mPD-1; 5 mg/kg IP twice 
weekly) were administered to mice either alone or in combination for 16 days. The 
combination was tolerated with no treatment-related death. Almost all tumors achieved 
complete regression upon treatment with niraparib, anti-mPD-1, and the combination. 
Complete regression was first observed on treatment Day 16 in 2 of 6, 1 of 6, and 4 of 6 
mice from the niraparib, anti-mPD-1, and combination groups, respectively [Wang, 
2019]. These results suggest that the therapeutic approach of combining niraparib with a 
PD-1 inhibitor such as dostarlimab may provide additional benefit for participants with 
HRd tumors.  
Niraparib and anti-PD-1 combination treatment has also been evaluated in several 
syngeneic models representing breast cancer 1 and breast cancer 2 (BRCA1/2) wild-type 
tumors, one of which was the breast cancer mouse model MMTV-LPA1-T22. In a study 
of a syngeneic transplant breast cancer model, niraparib (50 mg/kg PO QD) and anti-PD-
1 antibody (10 mg/kg IV BIW) were administered to mice either alone or in combination 
for 15 days. While these tumors were moderately responsive to niraparib or anti-PD-1 
antibody alone, with average tumor growth inhibition of approximately 45% for niraparib 
and 30% for PD-1 antibody, synergistic antitumor activity with near-complete tumor 
growth inhibition (91%) was achieved with the combination. In a similar study using the 
lung squamous syngeneic model KLN205, stronger tumor growth inhibition was 
observed for the combination (52%) than for niraparib alone (36%) or anti-PD-1 alone 
(30.5%). Together, these data support the therapeutic approach of combining niraparib 
with anti-PD-1 agent in either BRCA1/2 mutant or wild-type tumors [Wang, 2019]. 
1.5.2.2. 
Clinical 
The Phase 2 MEDIOLA study enrolled 32 participants with germline BRCA mutated 
platinum-sensitive relapsed ovarian cancer. Participants received olaparib 300 mg PO 
twice daily for a 4-week run-in, followed by olaparib 300 mg PO twice daily and 
durvalumab 1.5 g IV every 4 weeks until progressive disease (PD). As of the final interim 

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data cutoff, the DCR at 12 weeks was 81% and the ORR was 63%. The most common 
Grace ≥3 AEs were anemia (9%), increased lipase (9%), increased amylase (6%), and 
neutropenia (3%) [Drew, 2018].  
The Phase 1/2 TOPACIO study enrolled 62 participants with recurrent ovarian cancer. 
Niraparib 200 mg PO and pembrolizumab 200 mg IV were administered on a 21-day 
cycle to 60 evaluable participants. The ORR was 18% (5% CR, 13% PR); including 47% 
participants with stable disease (SD), the DCR was 65%. Response rates in biomarker-
selected populations were as follows: 18% tumor BRCA mutation (tBRCAmut), 
14% HRDpos, 19% tumor BRCA wild type (tBRCAwt), and 19% HRDneg. With this 
combination, the rate of Grade >3 thrombocytopenia was 9%; no other safety signals 
were noted [Konstantinopoulos, 2019].  
Part A of Study 213351, referred to as IOLite or formerly referred to as Study 3000-01-
002, mentioned in Section 1.5.1.2, evaluated niraparib in combination with dostarlimab. 
These two agents have non-overlapping safety and metabolic profiles. No participants 
experienced DLT with niraparib 300 mg and dostarlimab 500 mg/m2. There were no new 
safety findings at either dose level.  
1.5.3. 
Combination of PD-1 inhibitor and Bevacizumab 
The immunomodulatory activities of vascular endothelial growth factor (VEGF) has been 
demonstrated nonclinically, including the ability to inhibit dendritic cell maturation 
[Dikov, 2005], and to promote the accumulation and activation of regulatory T-cells and 
myeloid-derived suppressor cells (MDSCs) [Gabrilovich, 2012]. VEGF-mediated 
immunosuppression in cancer was demonstrated in clinical settings, for example, the 
expression of VEGF in tumor tissue negatively correlates with intra-tumoral T-cell 
infiltration, and it is associated with poor patient survival in epithelial ovarian cancer. In a 
renal cell carcinoma xenograft model, niraparib treatment was capable of significantly 
reducing the numbers of circulating myeloid cells [Kusmartsev, 2008]. Furthermore, in a 
T-cell receptor transgenic mouse model which mimics the adoptive cell therapy for the 
treatment of metastatic melanoma in the clinical setting, anti-VEGF antibody 
significantly increased lymphocyte infiltration into tumors and enhanced the 
effectiveness of adoptive immunotherapy [Shrimali, 2010].  
In a Phase 1 clinical trial including 15 participants with refractory solid tumors, 
Aflibercept (a recombinant fusion protein consisting of VEGF-binding portions from the 
extracellular domains of human VEGF receptors 1 and 2) significantly increased the 
proportion of mature dendritic cells and improved the immune responses in a subset of 
participants with no increase in the proportion of MDSCs [Fricke, 2007]. In 
bevacizumab-treated colorectal cancer patients, it has been shown that there is an 
increase of peripheral T-cell compartments [Manzoni, 2010]. 
Multiple clinical trials have investigated the effect of combination of the checkpoint 
inhibitor and bevacizumab in metastatic melanoma and renal cell carcinoma. The 
combination of anti-PD-L1 and anti-VEGF, atezolizumab and bevacizumab, was recently 
reported in 10 renal cell carcinoma patients. The combination treatment increased the 
tumoral CD8+ T-cell infiltration and the antigen-specific T-cell migration, which is 
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atezolizumab and bevacizumab was also reported in 101 metastatic renal cell carcinoma 
patients in a Phase 2 study [Atkins, 2017]. The combination in PD-L1-positive 
participants in the first-line setting resulted in antitumor activity, and preliminary activity 
in the second-line setting was demonstrated in participants who crossed over to 
atezolizumab and bevacizumab. First-line atezolizumab and bevacizumab versus 
sunitinib have been evaluated in a Phase 3 study [Motzer, 2018]. 
Part D of study 3000-01-002 evaluated dostarlimab in combination with paclitaxel, 
carboplatin and bevacizumab. No DLTs were observed in 6 participants. Part D 
established the safety of dostarlimab 
 in combination with paclitaxel 175 
mg/m2 and carboplatin AUC. 
1.5.4. 
Combination of Niraparib and Bevacizumab 
Tumor cells with a deficiency in homologous recombination are exquisitely sensitive to 
PARP inhibitors due to synthetic lethality. It has been observed that for tumors without 
genetic or epigenetic defects in homologous recombination pathway genes, a functional 
state of HRD may be induced by hypoxia through transcriptional downregulation of 
homologous recombination-related genes, including RAD51 and BRCA1 [Bryant, 2007]. 
In addition, cyclic (acute) hypoxia and reoxygenation can induce both single-strand and 
double-strand DNA breaks within tumor cells due to increased levels of reactive oxygen 
species [Bindra, 2004; Bindra, 2007; Lim, 2014]. These 2 mechanisms working together 
may lead to heightened sensitivity to PARP inhibitors when cells are under hypoxic stress 
exerted by angiogenesis inhibitors. It has been observed that PARP inhibitors selectively 
induce apoptosis in hypoxic tumor regions in vivo, supporting the idea of contextual 
synthetic lethality between hypoxia-induced functional HRD and PARP inhibition 
[Mehibel, 2021].  
In the clinical setting, preliminary evidence of clinical efficacy has been observed in 
participants with platinum-sensitive ovarian cancer treated with either niraparib 
combined with bevacizumab (ENGOT-OV24/AVANOVA trial) or olaparib combined 
with cediranib (Phase 2), irrespective of their BRCA mutation or HRD status [Liu, 2017]. 
The primary analysis of the AVANOVA trial showed a 6.4-month improvement in 
median PFS with the combination of niraparib and bevacizumab over niraparib alone 
with median PFS (ITT) of 11.9 vs 5.5 (adjusted HR: 0.35; p<0.0001). The benefit 
observed by the combination was in the range for participants with a PFS of 6 to 12 
month (11.3 vs 2.2 months, p=0.0006) or >12 months (13.1 vs 6.1 months, p=0.0062) and 
participants with HRD-positive tumors (11.9 vs 6.1 months, p=0.0019) or HRD-negative 
tumors (11.3 vs 4.2 months, p=0.0129). The combination showed a median PFS in 
participants with BRCA-mutant tumors of 14.4 vs 9.0 months (p=0.0947) and a 
statistically significant advantage to participants with BRCA-wild type tumors (11.3 vs 
4.2 months, p=0.0001). These data provide a strong rationale for combining a PARP 
inhibitor with an angiogenesis inhibitor [Mirza, 2019].  
Niraparib and bevacizumab in combination with dostarlimab is currently being evaluated 
in Part C of Study 3000-01-002 (IOLite). This open-label, Phase 1b study is being 
conducted in 9 parts in participants with advanced or metastatic cancer to evaluate DLTs, 
safety, and tolerability. As of May 2019, 6 participants have been treated with 
 
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 once daily and dostarlimab in combination with bevacizumab 15 mg/kg Q3W; 1 
participant experienced an AE of Grade 3 carotid artery intimal tear attributed to the 
combination of niraparib and bevacizumab. Seven participants have been treated with 
niraparib 300 mg once daily and dostarlimab in combination with bevacizumab; 1 
participant experienced an AE of Grade 4 neutropenia attributed to niraparib and 
dostarlimab. 
Overall, the combination of niraparib and bevacizumab appears to be safe for 
administration, with a manageable safety profile. Adverse events observed to date are 
consistent with those of the individual components and are readily managed through 
routine laboratory testing (i.e., complete blood count [CBC]), clinical surveillance (i.e., 
BP monitoring), and adherence to the recommended dose modifications. 
1.5.5. 
Rationale for Combination Therapies Proposed  
Based on the totality of available clinical safety data on the combinations of agents under 
investigation in FIRST as described above, the Sponsor believes the combination of 
dostarlimab plus platinum-based chemotherapy±bevacizumab and dostarlimab plus 
niraparib±bevacizumab will be safe and tolerable for participants in FIRST. Furthermore, 
FIRST will be continuously monitored by an Independent Data Monitoring Committee 
(IDMC) for any emergent safety issues and appropriate measures will be taken in 
accordance with the protocol should any issues occur.  
1.6. 
Rationale for Current Study 
Availability of better surgical and chemotherapy options has increased the survival of 
patients with advanced ovarian cancer over the last 2 decades, but treatments remain 
nonselective, resulting in significant toxicity and short-lived antitumor responses 
[Grunewald, 2017]. Targeted therapies including the targets of DNA repair, combined 
with VEGF inhibition and ICIs may provide a better outcome for the treatment of the 
heterogeneous disease. Preclinical studies report synergistic effect of these drugs when 
combined [Chan, 2010].  
With the PRIMA trial, TESARO intends to improve patient responses in the first-line 
setting by investigating niraparib maintenance treatment in patients with advanced 
ovarian cancer following response on first-line platinum-based combination 
chemotherapy. Topline data from the PRIMA trial are presented in Section 1.2. However, 
an unmet need still exists to maximize patient response to chemotherapy in the first-line 
treatment setting, to broaden the eligible maintenance population beyond platinum 
responders, and to deepen the clinical benefit in first-line maintenance. 
Ovarian cancer is a complex disease with significant genetic and molecular heterogeneity 
[Grunewald, 2017]. The high expression of VEGF receptor, PD-L1 expression, and DNA 
damage in ovarian tumors provide several targets for treatment and maintenance of 
disease response.  
This study’s design will enable Investigators to provide participants with the current SOC 
for advanced ovarian cancer patients as it has changed during study conduct. Of note, 
during the study’s course, results from pivotal studies have emerged that support the 
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incorporation of PARP inhibitors as first-line treatment of advanced ovarian cancer. As 
such, the study is adapted to incorporate evolving treatment paradigms in advanced 
ovarian cancer patients to ensure that study participants will have access to the most 
current regimen with or without investigational treatment while maintaining the integrity 
of the study.  
The FIRST study will evaluate the potential to augment the standard carboplatin-
paclitaxel regimen with dostarlimab±bevacizumab following diagnosis of late-stage 
ovarian cancer, followed by maintenance regimen of niraparib as a single agent or in 
combination with dostarlimab±bevacizumab. There are both manageable safety and 
non-overlapping metabolic profiles (refer the current versions of the niraparib IB [GSK 
Document Number RPS-CLIN-108400], the niraparib package insert [ZEJULA 
(niraparib) capsules for oral use, 2017], the bevacizumab [Genentech/Roche US] package 
insert [AVASTIN®, 2016], and the dostarlimab IB [GSK Document Number RPS-CLIN-
106356] for details) and nonclinical data suggesting possible synergistic interaction 
between PARP inhibitors and immune checkpoint or anti-angiogenic inhibitors. The PK 
profile and 
 of dostarlimab, during both combination 
treatments, will be evaluated. 
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2. 
TRIAL OBJECTIVES AND PURPOSE 
2.1. 
Primary Objective 
The primary objective is to compare the progression free survival (PFS) of platinum-
based combination therapy, dostarlimab, and niraparib treatment (Arm 3) to platinum-
based combination therapy and niraparib treatment (Arm 2) in participants with Stage III 
or IV high-grade nonmucinous epithelial ovarian cancer. 
 
  
2.2. 
Secondary Objectives 
Secondary objectives comparing platinum-based combination therapy, dostarlimab, and 
niraparib (Arm 3) to platinum-based combination therapy and niraparib (Arm 2) will 
evaluate: 
• 
Overall survival (OS, 
 
• 
Blinded Independent Central Review (BICR) determined PFS per RECIST v1.1 
criteria 
• 
Health related quality of life (HRQoL) 
• 
TFST 
• 
TSST 
• 
Time from randomization to the earliest date of assessment of progression after 
initiation of subsequent anticancer therapy following study treatment or death by 
any cause (PFS2) 
• 
ORR 
  
• 
DOR 
  
• 
DCR 
  
• 
PK and immunogenicity of dostarlimab  
• 
PK of niraparib 
Secondary objectives for platinum-based combination therapy (Arm 1), platinum-based 
combination therapy and niraparib (Arm 2) and platinum-based combination therapy, 
dostarlimab, and niraparib (Arm 3) for all participants will evaluate: 
• 
Safety and tolerability 
2.3. 
Exploratory Objectives 
Exploratory objectives include the following: 
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3. 
INVESTIGATIONAL PLAN 
3.1. 
Overall Study Design 
This is a global, multicenter, randomized, double-blind, controlled, Phase 3 study in 
participants with newly diagnosed Stage III or IV high-grade nonmucinous epithelial 
ovarian, fallopian tube, or peritoneal cancer (collectively referred to as “ovarian cancer”). 
The currently recommended SOC for the first-line treatment of Stage III or IV ovarian 
cancer is a combination of paclitaxel-carboplatin, with or without concurrent and 
maintenance bevacizumab. Participants will receive SOC during the Cycle 1 
Chemotherapy Run-In Period before randomization at Cycle 2. Concurrent bevacizumab 
use must be determined prior to randomization at Cycle 2.  
Treatment Arm 1 
 
 
 
  
The study is open to participants with inoperable ovarian cancer, participants who have 
macroscopic residual disease at the end of the PDS and have recovered from PDS, and 
participants for whom platinum-based combination NACT is planned. Participants with 
Stage IIIC disease that has been completely resected (also known as complete 
cytoreduction score of ‘0’ [CC0]) are eligible if they are assessed by the Investigator to 
have one or more of the high-risk factors defined by the inclusion criteria. Bevacizumab 
will be allowed where it is part of the SOC according to local treatment guidelines and/or 
practices. 
3.1.1. 
Adaptation to Study Design 
This study’s design will enable Investigators to provide participants with the current SOC 
for advanced ovarian cancer as it has changed during study conduct. Of note, during the 
study’s course, results from pivotal studies have emerged that support the incorporation 
of PARP inhibitors as first-line treatment of advanced ovarian cancer. As such, the study 
is adapted to incorporate evolving treatment paradigms in advanced ovarian cancer 
participants in order to ensure that study participants will have access to the most current 
regimen or investigational treatment while maintaining the integrity of the study. Full 
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details on potential adaptations to the study design and participant disposition are located 
in Appendix 11. 
As a result, following Sponsor and Steering Committee discussions, participants were not 
enrolled into Arm 1 after Amendment 4 was approved at each site. Participants in Arm 1, 
Chemotherapy Treatment Period who are receiving (±bevacizumab) when Amendment 4 
is implemented, may complete the 6 cycles of chemotherapy. After completion of the 
Chemotherapy Treatment Period and confirmation of adequate hematologic parameters, 
those participants receiving bevacizumab as maintenance therapy may continue at the 
Investigator’s discretion. Participants in Arm 1, Maintenance Treatment Period who are 
receiving bevacizumab when Amendment 4 is implemented may continue bevacizumab 
therapy at the Investigator’s discretion. Investigators will remain blinded for those 
participants enrolled in Arm 1 and receiving bevacizumab at the time of implementation 
of Amendment 4. 
Participants in Arm 1 Chemotherapy Treatment Period who are not receiving 
bevacizumab when Amendment 4 is implemented, may continue the 6 cycles of 
chemotherapy. After completion of the Chemotherapy Treatment Period and 
confirmation of adequate hematologic parameters, those participants not receiving 
bevacizumab may start niraparib maintenance therapy as "follow-up anticancer 
treatment" at the Investigator’s discretion. Participants in Arm 1, Maintenance Treatment 
Period not receiving bevacizumab when Amendment 4 is implemented may start 
niraparib maintenance therapy as "follow-up anticancer treatment" if the time after Cycle 
6 Day 1 of the Chemotherapy Treatment Period is ≤12 weeks. Participants will be 
permitted to remain on study until withdrawal of consent, sponsor decision to terminate 
study or death. Participants who do not elect to receive niraparib or bevacizumab 
maintenance will be discontinued from the study treatment and given the option to stay in 
the study for follow-up. In order to facilitate this adaptation, Investigators will be 
unblinded for those participants enrolled in Arm 1 and not receiving bevacizumab at the 
time of implementation of Amendment 4. The schedule of events for these participants is 
shown in Table 18.  
In total, 
 
 
 
Following the analysis conducted at the 31 October 2024 DCO date, no further efficacy 
analyses will be conducted for the study, as outlined in Section 9.6. Consequently, the 
scope of data collection is reduced, aligning with the revised schedule of events prior to 
PACT detailed in Table 16. 
Participants may access treatment outside of the study protocol prior to PACT by the 
DCO date for the final analysis by either a rollover study, Managed Access route, other 
potential mechanism of access or if the product is commercially available and accessible. 
Following the DCO date for the final analysis, Study 213350 (FIRST) may move into the 
Post Analysis Continued Treatment (PACT) phase where the study remains open only to 
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provide continued access to study treatment for participants who are continuing to derive 
clinical benefit in the opinion of the Investigator and cannot access the treatment outside 
of the study protocol by the time of the final analysis DCO date. At that time, the 
collection of new data for participants who no longer receive study intervention will stop 
entirely and will be considered to have completed the study. The clinical study database 
will be closed to new data following the DCO date for the final analysis. Participants still 
clinically benefiting from study intervention at the time of the PACT phase may continue 
to receive study treatment and only serious adverse events (SAEs), AEs leading to study 
intervention discontinuation, overdose, adverse events of special interest (AESIs), and 
pregnancy cases will be reported directly to the sponsor. Alternative continued treatment 
access outside of this study may be implemented, as it becomes available. 
Figure 1: 
Study Design 
 
 
 
 
 
 
  
b All participants previously randomized to placebo and not receiving bevacizumab will be unblinded and 
provided the option to receive niraparib maintenance if they have received chemotherapy or discontinued 
chemotherapy ≤12 weeks. 
Pre-Screening Period 
During the Pre-Screening Period, participants may sign a pre-Screening informed consent 
form to allow collection of limited tumor and blood samples. The purpose of this period 
is to ensure that the required tumor tissue sample is submitted, the results from the 
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 blood sample required for randomization are 
available, and to ensure that the 
 blood sample is collected prior to 
chemotherapy and if possible, prior to PDS; otherwise, the 
 blood sample 
may be collected after PDS. The blood sample for 
 is required. 
The Pre-Screening Period can take place within the 14 days prior to the Screening Period, 
defined as the date of signing the main informed consent, but does not have to encompass 
the full period. A participant can move to the Screening Period once deemed able.  
Screening Period 
During the Screening Period, participants will sign the main consent form and complete 
all assessments required to determine eligibility into the study. The Screening Period is 
within 28 days prior to Cycle 1 Day 1 (C1D1) of the Chemotherapy Run-In Period.  
Chemotherapy Run-In Period (Cycle 1) 
Prior to randomization, all participants will receive 1 cycle of paclitaxel-carboplatin 
during a Chemotherapy Run-In Period (Section 3.3.1). Participants may also receive 
bevacizumab with paclitaxel-carboplatin as part of SOC per local practice. However, 
bevacizumab must not be administered less than 28 days before or 28 days following 
major surgery, and post-operative incisions must be fully healed. The determination to 
use bevacizumab must be made prior to randomization. Participants will be randomized 
following Cycle 1, prior to treatment in Cycle 2 during the Chemotherapy Treatment 
Period. Randomization may occur up to one week prior to Cycle 2 Day 1. 
IP chemotherapy and weekly paclitaxel will not be allowed. 
Chemotherapy Treatment Period (Cycles 2 to 6) 
Prior to chemotherapy administration of Cycle 2, all of the following criteria must be 
met:  
• Absolute neutrophil count (ANC) ≥1,500 cells/µL, or ≥1,000 cells µL if 
granulocyte-colony stimulating factor (G-CSF) is to be administered. 
• Platelet count ≥100,000 /µL 
• Hemoglobin ≥8 g/dL 
Thereafter, re-treatment criteria for remaining chemotherapy Cycles 3 to 6 should be in 
accordance with treatment guidelines per local practice. 
Following randomization, participants who have inoperable disease or who have 
undergone PDS will receive cycles 2 to 6 of paclitaxel-carboplatin, for a total of 6 cycles 
of chemotherapy inclusive of Cycle 1. Participants will also receive dostarlimab/placebo 
in combination with paclitaxel-carboplatin started with Cycle 2 of chemotherapy, for a 
total of 5 cycles (Section 3.3.1). Participants may also receive bevacizumab with 
paclitaxel-carboplatin as part of SOC per local practice. However, bevacizumab must not 
be administered less than 28 days before or 28 days following major surgery, and 
post-operative incisions must be fully healed. 
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Participants for whom NACT is planned will receive 3 to 4 cycles of 
paclitaxel-carboplatin prior to interval debulking surgery (inclusive of Cycle 1) and 2 to 3 
additional cycles of paclitaxel-carboplatin following surgery for a maximum of 6 cycles 
of chemotherapy that cannot be extended. Interval debulking surgery planned after 6 
cycles of chemotherapy should be discussed with the Sponsor. These participants will 
also receive dostarlimab/placebo, which will be started with Cycle 2 of chemotherapy, for 
a total of 5 cycles. Chemotherapy and dostarlimab/placebo will resume upon recovery of 
surgery. Participants for whom NACT is planned may receive bevacizumab with 
paclitaxel-carboplatin per local practice; however, bevacizumab must not be administered 
less than 28 days before or 28 days following major surgery, and post-operative incisions 
must be fully healed. 
IP chemotherapy and weekly paclitaxel will not be allowed. 
Maintenance Treatment Period  
Participants who complete the Chemotherapy Treatment Period without PD will start the 
Maintenance Treatment Period 3 weeks after Cycle 6 Day 1 (Section 3.3.2). 
Dostarlimab/placebo ± bevacizumab will continue in the Maintenance Treatment Period 
in combination with oral niraparib maintenance treatment, per study schedule. However, 
the start of niraparib will be delayed at least 6 weeks after Cycle 6 Day 1 and up to 9 
weeks after to allow for adequate recovery of hematologic toxicity. 
Prior to receiving first dose of oral niraparib maintenance treatment, participants must 
have a CBC that demonstrates adequate recovery from hematologic toxicity from 
chemotherapy. 
• Absolute neutrophil count (ANC) ≥1,500 cells/µL 
• Platelet count ≥100,000 /μL 
• Hemoglobin ≥9 g/dL 
• BP <150/100 mmHg 
Weekly CBC is to be performed for the first 4 weeks from the start of niraparib in the 
Maintenance Treatment Period as follows: 
1. Week 1 (Day of first dose): Cycle X Maintenance Day 1 (-3 day window) 
2. Week 2: Cycle X Day 8 (no window, 7 days from First Dose) 
3. Week 3: Unscheduled Visit (no window, 14 days from First Dose)  
4. Week 4: Cycle X+1 Maintenance Day 1 (-3 day window)  
During the Maintenance Treatment Period, participants will receive oral niraparib daily 
and IV dostarlimab/placebo on Day 1 of every other Cycle (every 6 weeks) for up to 3 
years in the absence of disease progression, unacceptable toxicity, participant withdrawal, 
or Investigator’s decision. Participants who continue to derive benefit from study 
treatment based on continuation of best overall response indicated by imaging, remain 
clinically stable, and are willing to continue study visits and assessments may continue to 
receive niraparib and/or dostarlimab/placebo beyond 3 years following consultation with 
the investigator and the Sponsor. After completing 1 year of maintenance treatment (=17 

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cycles [±1] of niraparib) and 9 cycles [±1] of dostarlimab/placebo), and if not receiving 
bevacizumab, participants may return for clinic visits and assessments every 6 weeks, to 
coincide with the dostarlimab/placebo IV administration (beginning with C19M and 
continuing with odd cycles only). Participants will be dispensed 
 of niraparib 
beginning with cycle C17M and continuing with odd cycles until the end of treatment. 
Participants on any of the 3 Arms may continue bevacizumab Q3W for up to 15 months 
or a total of 22 consecutive or non-consecutive cycles (inclusive of bevacizumab 
administered during the Chemotherapy Treatment Period) as per local practice. At 
completion of bevacizumab treatment, participants may return for clinic visits and 
assessments every 6 weeks, to coincide with the dostarlimab/placebo IV administration. 
It is recommended that drugs be administered 
 The recommended order of administration is provided 
below, unless local clinical practice or institutional policies differ:  
• During the Chemotherapy Treatment Period, 
 
 
  
• During the Maintenance Treatment Period, 
 
 
3.2. 
Number of Participants 
In total, 
 have been randomized into the study. The study started with a 
 
 Arm 1 BCRAwt participant enrollment was stopped after implementation 
of Amendment 4. 
 
  
3.3. 
Treatment Assignment 
3.3.1. 
Chemotherapy Run-In and Treatment Period 
During the Chemotherapy Treatment Period, participants who have inoperable ovarian 
cancer, who have undergone PDS, or who are planned to undergo IDS, and who are 
considered as candidates for systemic platinum-based combination chemotherapy, will 
receive paclitaxel followed by carboplatin on Day 1 of a 21-day treatment cycle. All 
participants for whom NACT is planned will receive 3 to 4 cycles of chemotherapy prior 
to IDS (inclusive of Cycle 1) and 2 to 3 additional cycles following surgery for a 
maximum of 6 cycles of chemotherapy that cannot be extended. Interval debulking 
surgery planned after 6 cycles of chemotherapy should be discussed with the Sponsor. 
Initiation of the subsequent cycles post-IDS will be upon post-operative recovery of the 
participant. Bevacizumab may be administered every 21 days (Q21D) per local practice 
SOC but should not be administered less than 28 days before or 28 days following major 
surgery. Bevacizumab use must be determined prior to randomization at Cycle 2. 
Participants will also receive 
 dostarlimab/placebo after completion of each 
carboplatin infusion on Day 1 of a 21-day cycle starting with Cycle 2. 
IP chemotherapy and weekly paclitaxel will not be allowed. 
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3.3.2. 
Maintenance Treatment Period 
After completion of the sixth cycle of chemotherapy, niraparib will not be administered 
until bone marrow recovery is confirmed and will be delayed at least 6 weeks after Cycle 
6 Day 1. All participants who received dostarlimab/placebo and/or bevacizumab during 
the Chemotherapy Treatment Period will continue to receive those agents during the bone 
marrow recovery period starting 3 weeks after Cycle 6 Day 1. 
Participants who do not have PD on first-line chemotherapy and have recovery to 
baseline of any hematologic toxicities (see Section 3.1) will enter the Maintenance 
Treatment Period. Oral niraparib (all arms) will be dispensed to participants on Day 1 of 
Q21D cycle beginning with Cycle 2 or Cycle 3 of the Maintenance Treatment Period for 
up to 3 years in the absence of PD, unacceptable toxicity, participant withdrawal, or 
Investigator’s decision.  
Participants will receive dostarlimab/placebo at 
 on Day 1 of every other 
maintenance cycle (i.e., every 6 weeks) beginning with Maintenance Cycle 1 for up to 
3 years in the absence of disease progression, unacceptable toxicity, participant 
withdrawal, or Investigator’s decision. Participants on any arm may continue 
bevacizumab on Day 1 of each 21-day cycle beginning with Maintenance Cycle 1 for up 
to 15 months (inclusive of bevacizumab administered during the Chemotherapy 
Treatment Period) per local practice.  
Participants who continue to derive benefit from study treatment based on continuation of 
best overall response indicated by imaging, remain clinically stable, and are willing to 
continue study visits and assessments may continue to receive niraparib and/or 
dostarlimab/placebo beyond 3 years following consultation with the investigator and the 
Sponsor. 
The starting dose of niraparib will be based on the participant’s actual body weight and 
platelet count, as measured prior to dosing in the Maintenance Treatment Period. 
Participants with an actual body weight of ≥77 kg and a platelet count of ≥150,000/μL 
will take 
 at each dose administration. 
Participants with an actual body weight of <77 kg, a platelet count of <150,000/μL, or 
both will take 
 
Dose modifications will not be based upon changes in the participant’s actual body 
weight during study participation (see Section 3.4). 
Additionally, BP and heart rate will be performed weekly for the first 8 weeks from the 
first dose of niraparib in the Maintenance Treatment Period. 
After completing 1 year of maintenance treatment (=17 cycles [±1] of niraparib) and 9 
cycles [±1] of dostarlimab/placebo, and if not receiving bevacizumab, participants may 
return for clinic visits and assessments every 6 weeks, to coincide with the 
dostarlimab/placebo IV administration. If receiving bevacizumab treatment, and 
following completion, participants may return for clinic visits and assessments every 6 
weeks, to coincide with the dostarlimab/placebo IV administration. 
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Treatment details are provided in Table 7 (Arm 1), and Table 8 (Arm 2 and Arm 3). It is 
recommended that drugs be administered 
 
 The recommended order of administration is provided 
below, unless local clinical practice or institutional policies differ:  
• During the Chemotherapy Treatment Period, 
 
 
  
• During the Maintenance Treatment Period, 
 
 
Table 7: 
Study Treatment (Standard of Care and Investigational Therapy) 
Dosage and Mode of Administration: Arm 1 (Post-Amendment 4)  
Treatment 
Combination 
Dosage and Frequency 
Mode of 
Administration 
Chemotherapy Run-In Period (Cycle 1) 
Paclitaxel 
175 mg/m2 on Day 1 Q21D 
180-minute IV infusion 
Carboplatin 
AUC of 5 to 6 mg/mL/min on Day 1 
Q21D 
60-minute IV infusion 
Bevacizumab  
7.5 mg/kg Q21D or 15 mg/kg Q21D for 
a total of 15 months 
90-minute (±15 min) 
IV infusiona 
Chemotherapy Treatment Period (Cycles 2 to 6) 
Dostarlimab Placebob 
 
 
 
Paclitaxele 
175 mg/m2 on Day 1 Q21D 
180-minute IV infusion 
Carboplatine 
AUC of 5 to 6 mg/mL/min on Day 1 
Q21D 
60-minute IV infusion 
Bevacizumab  
7.5 mg/kg Q21D or 15 mg/kg Q21D for 
a total of 15 months 
90-minute (±15 min) 
IV infusiona 
Maintenance Treatment Periodd, h 
Dostarlimab Placebob 
 on Day 1 every 6 weeks to 
continue up to 3 yearsf in the absence of 
disease progression, unacceptable 
toxicity, participant withdrawal, or 
Investigator decision 
 
 
Bevacizumab 
7.5 mg/kg Q21D or 15 mg/kg Q21D for 
a total of 15 months 
90-minute (±15 min) 
IV infusiona 
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Treatment 
Combination 
Dosage and Frequency 
Mode of 
Administration 
Niraparib/Placeboc 
 
 
 to 
continue up to 3 yearsg in the absence of 
disease progression, unacceptable 
toxicity, participant withdrawal, or 
Investigator decision 
Oral 
Abbreviations: AE=adverse event; AUC=area under the curve; IV=intravenous. 
a The initial dose of bevacizumab will be delivered over 90 (±15) minutes. If the first infusion is tolerated 
without infusion-associated AEs (fever and/or chills), the second infusion may be delivered over 60 (±10) 
minutes. If the 60-minute infusion is well-tolerated, all subsequent infusions may be delivered over 30 
(±10) minutes. Sites can defer to local practice for administration of bevacizumab if different from the 
process described here.  
b Dostarlimab placebo will be administered using a 
 
 for those participants in Arm 1 who remain blinded and receiving bevacizumab only. 
For participants who are unblinded, dostarlimab placebo will not be administered. 
c All participants previously randomized to placebo and not receiving bevacizumab will be unblinded and 
provided the option to receive niraparib. Participants should be dosed according to the criteria specified in 
Section 3.4.1. The first dose will be administered at the study site. Participants will be instructed to take 
their study medication dose at the same time each day. Participants must swallow and not chew all 
. The consumption of water and food is permissible. 
d After completing 1 year of maintenance treatment (=17 cycles [±1] of niraparib), and if not receiving 
bevacizumab, participants may return for clinic visits and assessments every 6 weeks. If receiving 
bevacizumab treatment, following its completion, participants may return for clinic visits and assessments 
every 6 weeks, to coincide with the dostarlimab placebo IV administration.  
e Sites can refer to local practice guidelines for any dose modifications/delays associated with 
chemotherapy (carboplatin and paclitaxel). 
f Participants who continue to derive benefit from study treatment based on continuation of best overall 
response indicated by imaging, remain clinically stable, and are willing to continue study visits and 
assessments may continue to receive dostarlimab placebo beyond 3 years following consultation with the 
investigator and the Sponsor.  
g Participants who continue to derive benefit from study treatment based on continuation of best overall 
response indicated by imaging, remain clinically stable, and are willing to continue study visits and 
assessments may continue to receive niraparib/placebo beyond 3 years following consultation with the 
investigator and the Sponsor. 
h For participant management following analysis (DCO 31 October 2024), prior to PACT, ongoing 
participants not previously unblinded according to Amendment 4 are to be centrally unblinded, followed 
by discontinuation of placebo treatment and the study.     
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Table 8: 
Study Treatment (Standard of Care and Investigational Therapy) 
Dosage and Mode of Administration: Arms 2 and 3  
Treatment 
Combination 
Dosage and Frequency 
Mode of 
Administration 
Chemotherapy Run-In Period (Cycle 1) 
Paclitaxel 
175 mg/m2 on Day 1 Q21D 
180-minute IV infusion 
Carboplatin 
AUC of 5 to 6 mg/mL/min on Day 1 
Q21D 
60-minute IV infusion 
Bevacizumab (optional) 
7.5 mg/kg Q21D or 15 mg/kg Q21D for 
a total of 15 months 
90-minute (±15min) 
IV infusiona  
Chemotherapy Treatment Period (Cycles 2 to 6) 
Dostarlimab placebo 
(Arm 2) or dostarlimab 
(Arm 3)b  
 
 
 
Paclitaxele 
175 mg/m2 on Day 1 Q21D 
180-minute IV infusion 
Carboplatine 
AUC of 5 to 6 mg/mL/min on Day 1 
Q21D 
60-minute IV infusion 
Bevacizumab (optional) 
7.5 mg/kg Q21D or 15 mg/kg Q21D for 
a total of 15 months 
90-minute (±15min) 
IV infusiona 
Maintenance Treatment Periodd, f 
Dostarlimab placebo 
(Arm 2) or dostarlimab 
(Arm 3)b  
 on Day 1 every 6 weeks to 
continue up to 3 yearsf in the absence of 
disease progression, unacceptable 
toxicity, participant withdrawal, or 
Investigator decision 
 
 
Bevacizumab (optional)  
7.5 mg/kg Q21D or 15 mg/kg Q21D for 
a total of 15 months 
90-minute (±15 min) 
IV infusiona 
Niraparibc 
 
 
 
 to continue up to 
3 yearsg in the absence of disease 
progression, unacceptable toxicity, 
participant withdrawal, or Investigator 
decision 
Oral  
Abbreviations: AE=adverse event; AUC=area under the curve; IV=intravenous; Q21D=every 21 days. 
a The initial dose of bevacizumab will be delivered over 90 (±15) minutes. If the first infusion is tolerated 
without infusion-associated AEs (fever and/or chills), the second infusion may be delivered over 60 (±10) 
minutes. If the 60-minute infusion is well tolerated, all subsequent infusions may be delivered over 30 
(±10) minutes. Sites can defer to local practice for administration of bevacizumab if different from the 
process described here. 
b Dostarlimab placebo (Arm 2) or dostarlimab (Arm 3) will be administered using a 
 
 
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c Participants should be dosed according to the criteria specified in Section 3.4.1. The first dose will be 
administered at the study site. Participants will be instructed to take their niraparib dose at the same time 
each day. Participants must swallow and not chew all 
. The consumption of water and 
food is permissible. 
d After completing 1 year of maintenance treatment (=17 cycles [±1] of niraparib) and 9 cycles [±1] of 
dostarlimab placebo [Arm 2] or dostarlimab [Arm 3]), and if not receiving bevacizumab, participants may 
return for clinic visits and assessments every 6 weeks, to coincide with the dostarlimab/placebo IV 
administration. If receiving bevacizumab treatment, following its completion, participants may return for 
clinic visits and assessments every 6 weeks, to coincide with the dostarlimab placebo (Arm 2) or 
dostarlimab (Arm 3) IV administration. 
e Sites may refer to local practice guidelines for any dose modifications/delays associated with 
chemotherapy (carboplatin and paclitaxel). 
f Participants who continue to derive benefit from study treatment based on continuation of best overall 
response indicated by imaging, remain clinically stable, and are willing to continue study visits and 
assessments may continue to receive dostarlimab/placebo beyond 3 years following consultation with the 
investigator and the Sponsor. For participant management following analysis (DCO 31 October 2024), 
prior to PACT, participants ongoing on study drugs are to be centrally unblinded and administration of 
dostarlimab placebo will be discontinued. Niraparib study drug may be continued, if applicable. 
g Participants who continue to derive benefit from study treatment based on continuation of best overall 
response indicated by imaging, remain clinically stable, and are willing to continue study visits and 
assessments may continue to receive niraparib beyond 3 years following consultation with the investigator 
and the Sponsor.  
For PACT phase, niraparib (capsule/tablet) and dostarlimab will be open-label. 
3.3.3. 
Duration of Treatment 
3.3.3.1. 
Planned Study Conduct Duration 
This study will last approximately 94 months (time from first participant enrolled until 
last patient last visit). 
3.3.3.2. 
Planned Study Treatment Duration 
Participants who continue to derive benefit from study treatment based on continuation of 
best overall response indicated by imaging, remain clinically stable, and are willing to 
continue study visits and assessments may continue to receive niraparib and/or 
dostarlimab/placebo beyond 3 years following consultation with the investigator and the 
Sponsor. Participants may continue bevacizumab maintenance (administered during the 
chemotherapy portion and maintenance portion) for up to 15 months or a total of 22 
consecutive or non-consecutive cycles (inclusive of bevacizumab administered during the 
Chemotherapy Treatment Period) as per local practice and in the absence of PD, 
unacceptable toxicity, or participant withdrawal, or based on Investigator’s decision. 
For participant management following analysis (DCO 31 October 2024), prior to PACT, 
participants ongoing on study drugs are to be centrally unblinded and dostarlimab 
placebo administration is to be discontinued (i.e., Arm 1 niraparib placebo and/or 
dostarlimab placebo [not previously unblinded according to Amendment 4] and Arm 2 
dostarlimab placebo). Arm 1 participants will be discontinued from the study following 
niraparib placebo and/or dostarlimab placebo discontinuation. Arm 2 participants may 
continue niraparib study drug, if applicable. 
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Following unblinding, prior to PACT, participants who are deriving clinical benefit from 
study treatment as assessed by the Investigator may transition to continue receiving 
treatment outside of the study, as it becomes available and accessible. Refer to 
Section 5.5 for further details. 
For PACT, Study treatment will continue for up to 3 years from the final DCO date 
(Section 4.3.1), or until transition to an alternative method of continued treatment access 
outside of the study (Section 5.5), or until manufacturing of the product ceases, or until a 
study intervention discontinuation criterion (Section 4.3.1), as assessed by the 
Investigator, has been met, whichever occurs first. Alternative continued treatment access 
outside of this study may be implemented, as it becomes available. Refer to Sections 5.5 
and 5.6 for further details. 
3.4. 
Dose Adjustment Criteria 
3.4.1. 
Niraparib 
To manage adverse reactions, consider interruption of treatment, dose reduction, or dose 
discontinuation. The recommended dose modifications for adverse reactions are listed in 
Table 9, Table 10, and Table 11. 
For participants whose initial dose is 
, dose 
reductions to 
 and subsequently to 
 
 will be allowed. No further dose reduction will be allowed. 
For participants whose initial dose is 
, dose reduction to 
 will be allowed. No further dose reduction will be 
allowed. 
Table 9: 
Niraparib Dose Reduction for Adverse Reactions 
Dose level 
Initial Dose: 
 
 
Initial Dose: 
 
Starting dose 
First dose reduction 
Second dose 
reduction 
N/A 
Abbreviations: AE=adverse event; N/A=not applicable. 
a If further dose reduction is required due to AE management, discussion with the Sponsor is required. 
For PACT, niraparib (capsule/tablet) and dostarlimab will be open-label. 
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Table 10: 
Dose Modifications for Non Hematologic Adverse Reactions 
Non-hematologic NCI-CTCAE Grade ≥3 adverse 
reaction where prophylaxis is not considered feasible or 
adverse reaction event persists despite treatment 
Withhold niraparib for a maximum 
of 28 days or until resolution of 
adverse reaction. 
Resume niraparib at a reduced dose 
per Table 9. Up to 1 dose reduction 
is permitted. 
NCI-CTCAE Grade ≥3 treatment related adverse 
reaction event lasting more than 28 days while the 
participant is administered niraparib 
 
Discontinue medication. 
PRES: There have been reports of PRES in participants 
receiving niraparib 
Discontinue niraparib and treat 
specific symptoms including 
hypertension. 
Abbreviations: NCI-CTCAE=National Cancer Institute - Common Terminology Criteria for Adverse 
Events; PRES= Posterior Reversible Encephalopathy Syndrome. 
 
Table 11: 
Dose Modifications for Hematologic Adverse Reactions 
Weekly blood draws for CBC will be monitored until the adverse reaction resolves, and to 
ensure safety of the new dose, weekly blood draws for CBC will also be required for an 
additional 4 weeks after the adverse reaction has been resolved to the specified levels, after 
which monitoring every 4 weeks may resume. 
Platelet count <100,000/µL 
First occurrence: 
• 
Withhold niraparib for a maximum of 28 days and 
monitor blood counts weekly until platelet counts 
return to ≥100,000 /µL. 
• 
Resume niraparib at the same or reduced dose per 
Table 9 
• 
If nadir platelet count was <75,000/µL, resume at 
a reduced dose after recovery. 
Second occurrence: 
• 
Withhold niraparib for a maximum of 28 days and 
monitor blood counts weekly until platelet counts 
return to ≥100,000/µL. 
• 
Resume niraparib at a reduced dose per Table 9. 
• 
Discontinue niraparib if the platelet count has not 
returned to acceptable levels within 28 days of the 
dose interruption period or if the participant has 
already undergone dose reduction to 
 
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Neutrophil <1,000/µL or  
Hemoglobin <8 g/dL 
• 
Withhold niraparib for a maximum of 28 days and 
monitor blood counts weekly until neutrophil 
counts return to ≥1,500/µL or hemoglobin returns 
to ≥9 g/dL. 
• 
Resume niraparib at a reduced dose per Table 9 
• 
Discontinue niraparib if neutrophil or hemoglobin 
level has not returned to acceptable levels within 
28 days of the dose interruption period, or if the 
participant has already undergone dose reduction 
to 
 
Hematologic adverse reaction 
requiring red blood cell and/or 
platelet transfusion 
• 
For participants with platelet count ≤10,000/μL, 
platelet transfusion should be considered. If there 
are other risk factors such as co-administration of 
anticoagulation or antiplatelet drugs, consider 
interrupting these drugs and/or transfusion at a 
higher platelet count. 
• 
RBC transfusion is at the discretion of the 
Investigator. 
• 
Resume niraparib at a reduced dose. 
MDS/AML 
Any suspected case of MDS/AML reported while a 
participant is receiving treatment or followed for post-
treatment assessments must be referred for evaluation to a 
local hematologist to perform bone marrow aspirate and 
biopsy as per local practice. The study site must receive a 
copy of the hematologist’s report of aspirate/biopsy 
findings, which must include a classification according to 
WHO, and other sample testing reports related to 
MDS/AML. If a diagnosis of MDS/AML is confirmed by 
a hematologist, the participant must permanently 
discontinue study treatment. 
Abbreviations: AML=acute myeloid leukemia; CBC=complete blood count; MDS=myelodysplastic 
syndrome; QD=once daily; RBC=red blood cell. 
3.4.2. 
Dostarlimab 
Adverse events (both non-serious and serious) associated with dostarlimab exposure may 
represent an immunologic etiology. These AEs may occur shortly after the first dose or 
several months after the last dose of treatment. 
In general, dostarlimab must be withheld for drug-related Grade 3 toxicities, as well as 
for certain immune-related adverse events of interest (irAEIs) but may be resumed upon 
recovery to Grade ≤1 and until the next scheduled cycle; dostarlimab will be permanently 
discontinued for any drug-related Grade 4 AE. Dostarlimab must be permanently 
discontinued for certain drug-related irAEIs as described in Table 12. If dostarlimab dose 
interruption is longer than 1 month, the Sponsor should be contacted to discuss the 
disposition of the participant. 
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Refer to the American Society of Clinical Oncology-NCCN guidelines for the overall 
management of immune-related AEs (irAEs). The specific irAEs typically observed with 
PD-1 antibodies will be managed according to the guidelines summarized below 
[Brahmer, 2018] 
Immune-Related Adverse Events of Interest and Guidelines for Management 
Given the mechanism of action of dostarlimab, it is anticipated that activation of cellular 
immune system can be manifested as irAEs. The fundamental principles of managing 
drug-related irAEs are discontinuation of the ICI, a course of corticosteroids and routine 
supportive measures based upon the severity of the irAE. Supportive measures may 
include hormone replacement and/or sub-specialist consultation. Guidelines for irAE 
management are available through the American Society of Clinical Oncology or the 
European Society of Medical Oncology [Brahmer, 2018; Haanen, 2017]. Based on 
available safety data from checkpoint inhibitors, TEAEs with the specific grades listed in 
Table 12 were selected as irAEs. The irAEs may be updated upon emerging data.  
For all drug-related irAEs listed in Table 12, dostarlimab should be withheld until the 
participant is clinically and metabolically stable and AEs are resolved to Grade 1. If 
systemic steroids are used as part of irAEI management, the total dose of daily steroids 
should be equal to or less than prednisone 10 mg at the time of resuming dostarlimab. 
Please refer to Table 12 for details on the management of dostarlimab dose delays and 
discontinuation for specific events. 
All treatment delays (including any missed doses) as well as discontinuations and the 
reason for delays, interruptions, or discontinuation of dostarlimab should be recorded in 
the electronic case report form (eCRF). 

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Table 12: 
Dostarlimab Guidelines for Immune-Related Adverse Events  
Toxicity 
Withhold Treatment for AE Grade 
Restarting Treatment/Discontinuation 
Diarrhea/colitis 
2 to 3 
Restart dosing when toxicity resolves to Grade 1. 
4 or recurrent Grade 3 
Permanently discontinue. 
AST, ALT, or increased 
bilirubin 
2 
(AST or ALT >3 and ≤5×ULN or 
total bilirubin >1.5 and ≤3×ULN) 
Restart dosing when toxicity resolves to Grade 1. 
3 to 4  
(AST or ALT >5×ULN or total 
bilirubin >3×ULN) 
Permanently discontinue.a 
T1DM or hyperglycemia 
3 to 4 hyperglycemia or T1DM 
(associated with metabolic acidosis 
or ketonuria) 
Restart dosing in appropriately managed, clinically and metabolically stable participants. 
Insulin replacement therapy is required. 
Immune-related encephalitis  
Any grade 
Permanently discontinue. 
Uveitis 
≥Grade 2 
Restart the treatment when toxicity resolves to Grade 1. For any recurrent uveitis or 
uveitis resistant to topical steroids, permanently discontinue treatment. 
Myositis 
2 to 3 
Restart the treatment when toxicity resolves to Grade 1 
Hypophysitis 
2 to 4 
For Grade 2 to 3, hold until hormonal therapy results in return to adequate levels by 
laboratory values and restart dosing when toxicity resolves to Grade 1. For recurrence or 
worsening of ≥Grade 2 hypophysitis after steroid taper has been completed and participant 
is on adequate hormone replacement therapy, permanently discontinue. For Grade 4, 
permanently discontinue. 
Adrenal insufficiency 
2 to 4 
Hold until hormonal therapy results in return to adequate levels by laboratory values and 
restart dosing when toxicity resolves to Grade 1. For recurrent or worsening ≥Grade 2 
adrenal insufficiency while adequate hormonal replacement is continuing, permanently 
discontinue study drug. 

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Toxicity 
Withhold Treatment for AE Grade 
Restarting Treatment/Discontinuation 
Hypo- and hyperthyroidism 
3 or 4 
Hold until hormonal therapy results in return to adequate levels by laboratory values and 
restart dosing when toxicity resolves to Grade 1. 
Infusion-related reaction 
2b 
Restart dosing when toxicity resolves to Grade 1. 
3 to 4 
Permanently discontinue. 
Pneumonitis 
2 
Restart dosing when toxicity resolves to Grade1. If Grade 2 recurs, permanently 
discontinue. 
3 to 4 or recurrent Grade 2 
Permanently discontinue. 
Severe exfoliative 
dermatologic events 
 
Grade 3 or Suspected DRESS, SJS or 
TEN 
Withhold. 
Grade 4 or Confirmed DRESS, SJS 
or TEN 
Permanently discontinue. 
Renal failure or nephritis 
2 with creatinine >1.5 to ≤3×ULN  
Restart dosing when toxicity resolves to Grade 1. 
>3 with creatinine >3×ULN 
Permanently discontinue. 
Myocarditis 
Grade 2, 3 or 4 
Permanently discontinue. 
Severe neurologic events 
(myasthenic 
syndrome/myasthenia gravis, 
Guillain Barré Syndrome, 
transverse myelitis) 
Grade 2, 3 or 4 
Permanently discontinue. 
Hemophagocytic 
lymphohistiocytosis 
Any grade 
Permanently discontinue. 
Recurrence of AEs after 
resolution to Grade ≤1 
3 to 4 
Permanently discontinue. 
Other irARs 
 
Based on severity and type of 
reaction (Grade 2 or 3) 
Restart dosing when toxicity resolves to Grade 1. 
Grade 4 or recurrent Grade 3 
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Abbreviations: AE=adverse event; ALT=alanine aminotransferase; AST=aspartate aminotransferase; PO=per oral; T1DM=type 1 diabetes mellitus; ULN=upper limit 
of normal. DRESS=drug reaction with eosinophilia and systemic symptom; irAR=immune related adverse reaction; SJS=Stevens Johnson Syndrome; TEN=toxic 
epidermal necrolysis 
a For participants with liver metastasis who begin treatment with Grade 2 AST or ALT, if AST or ALT increases by ≥50% relative to baseline and lasts for at least 
1 week, then study drug should be discontinued. 
b Upon resolution within 1 hour of stopping drug infusion, the infusion may be restarted at 
. Otherwise, 
study drug will be withheld until symptoms resolve, and the participant should be premedicated with diphenhydramine 50 mg PO (or equivalent dose of 
antihistamine) and acetaminophen 500-1,000 mg PO (or equivalent dose of antipyretic) for the next scheduled dose. Participants who develop Grade 2 toxicity despite 
adequate premedication should be permanently discontinued from further study treatment administration. 
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3.4.3. 
Bevacizumab 
Dose reductions of bevacizumab are not permitted in this study. Please refer to the local 
bevacizumab package insert. 
Bevacizumab treatment should be withheld no less than 28 days before and 28 days 
following major surgery. In participants who experience wound healing complications 
during the study, treatment with bevacizumab should be withheld until the wound is fully 
healed.  
3.4.4. 
Carboplatin and Paclitaxel 
Dose adjustments should be made per local practice guidelines. There are no dose 
escalations planned (including dose re-escalation after a dose reduction).  
Toxicities related to carboplatin and paclitaxel will be managed per local guidelines. If a 
participant has a suspected hypersensitivity reaction to either chemotherapy, the Sponsor 
should be consulted prior to discontinuation of either therapy. If a participant experiences 
hypersensitivity to carboplatin, then cisplatin may be used in place of carboplatin. 
Desensitization to carboplatin will not be allowed on study. If a participant experiences 
hypersensitivity or clinically significant neuropathy on paclitaxel treatment, docetaxel 
can be substituted per the Investigator’s discretion. 
Carboplatin (or cisplatin) and paclitaxel (or docetaxel) must be given on the same day; 
hence, delays in 1 study treatment should result in delay of all study treatments until they 
can all safely be given, except in the situation when a participant experiences toxicity 
related to bevacizumab. In this case, the bevacizumab should be omitted, and treatment 
can proceed with carboplatin (or cisplatin) and paclitaxel (or docetaxel). Bevacizumab 
can be administered at a later date, after the toxicities related to bevacizumab have 
resolved.  
For all participants, if the causality of an AE cannot be determined to 1 investigational 
agent, consider discontinuing both and speak to the Sponsor prior to any dose 
modification, including dose interruption, reduction, or withdrawal. 
3.5. 
Criteria for Study Termination 
The Sponsor may terminate this study at any time. The Sponsor will notify the 
Investigators when the study is to be placed on hold, completed, or terminated. 
3.6. 
Study Conduct 
3.6.1. 
Schedule of Events 
The schedule of events for the study is provided in Table 16.  

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3.6.2. 
Procedures and Assessments 
Treatment Cycles 
Treatment cycles are 21 days long. 
Visits should occur within ±3 days of the scheduled visit. This window also applies to 
study procedures, with all procedures allowed to be performed up to ±3 days of the 
scheduled visit. All times should be recorded using the 24-hour clock (e.g., 23:20, not 
11:20 PM). 
Interval Debulking Surgery (IDS) 
Participants for whom NACT is planned will receive 3 to 4 cycles of chemotherapy 
treatment prior to IDS (inclusive of Cycle 1) and an additional 2 to 3 cycles following 
surgery for a maximum of 6 cycles of chemotherapy that cannot be extended. Interval 
debulking surgery planned after 6 cycles of chemotherapy should be discussed with the 
Sponsor. Initiation of the subsequent cycles post-IDS will be upon post-operative 
recovery of the participant. Bevacizumab should not be administered less than 28 days 
before or 28 days following major surgery. Additionally, participants indicated for IDS 
will also have a pre-operative scan during the chemotherapy period. 
Radiographic Evaluation for Primary Outcome 
All participants are required to undergo radiographic evaluation throughout the study as 
described in the schedule of events and Appendix 6. RECIST v1.1 tumor assessment via 
computed tomography (CT) or magnetic resonance imaging (MRI) scan of the 
chest/abdomen/pelvis and clinically indicated areas is required at Screening, prior to IDS 
(if applicable), prior to the start of the maintenance period, and at regular intervals 
throughout the maintenance. If participant had CT/MRI of the chest/abdomen/pelvis and 
clinically indicated areas within the 28-day Screening window before C1D1 but prior to 
signing the informed consent form (ICF), the participant is not required to complete an 
additional CT/MRI scan for study Screening. CT/MRI scans completed during Screening 
prior to signing ICF must have been performed and available for submission per the 
image acquisition guidelines. If there are lesions in the chest and/or clinically indicated 
areas at Screening, then these areas should be screened at each subsequent timepoint. 
Otherwise, only abdomen/pelvis are required after Screening.  
During the Maintenance Treatment Period, imaging to assess disease status must occur at 
C1D1 (±14 days) of the Maintenance Treatment Period, and then every 4 months 
(±7 days) for 24 months, followed by every 6 months (±7 days) during the third year and 
every year thereafter until PD or initiation of follow-up anticancer therapy. 
 
 
 
 
 
 Following completion of 3 years of maintenance 
therapy, participants will be evaluated clinically with annual scans and additional 
unscheduled scans for suspicion of disease progression based on increases in CA 125 or 
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other suspicious symptoms. Participants may be considered for treatment beyond 3 years 
in consultation with the Sponsor. Prior to PACT (included in Amendment 10), RECIST v1.1. 
scans may occur at the time of clinical suspicion of disease progression or at an annual interval, 
whichever occurs first according to the PI discretion and local practice guidelines. 
 
 
 Clinically stable participants are 
those with no signs or symptoms of clinically significant or rapid progression of disease, 
including worsening of laboratory values or decline in performance status (ECOG) and 
no progressive tumor at critical anatomical sites (e.g., cord compression, intracranial 
tumor hemorrhage) requiring urgent medical intervention. 
 
 
Assessment of Response by RECIST 
 
 Details on RECIST v1.1, including evaluation of target and non-target lesions and 
definitions of response are provided in Appendix 4. PET/CT may be used to evaluate 
disease progression if an equivocal new lesion is seen on CT or MRI. 
Treatment and Assessment After Progression 
Investigator’s decision to continue treatment beyond the initial assessment of progression 
should be based on the participant’s overall clinical condition, including performance 
status, clinical symptoms, and laboratory data. A participant may receive 
dostarlimab/placebo treatment while waiting for confirmatory imaging if he/she is 
clinically stable per the following criteria: 
• Absence of signs and symptoms indicating clinically significant progression 
of disease, including worsening of laboratory parameters. 
• No decline in performance status. 
• Does not have rapid progression of disease. 
• Treatment beyond progression will not delay an imminent intervention to 
prevent serious complications of disease progression (e.g., central nervous 
system metastases and cord compression). 
Patient-Reported Outcomes and Health-related Quality of Life 
The following HRQoL assessments will be obtained: the European Quality of Life 
5-Dimension 5-Level Scale (EQ-5D-5L), the European Organisation for Research and 
Treatment of Cancer Quality of Life Questionnaire C30 (EORTC-QLQ-C30), and the 
EORTC-QLQ Ovarian Module OV28 (EORTC-QLQ-OV28). These will be collected at 
the following time points: 
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• Chemotherapy Run-In (21-day cycle): C1D1. 
• Chemotherapy Treatment (21-day cycles): Cycle 2/Day 1, and every 2 cycles 
thereafter (Cycle 4/Day 1, ending Cycle 6/Day 1).  
• Maintenance Treatment (21-day cycles): Day 1 of every cycle (i.e., 
Q21D±7 days) for the first 3 cycles, Day 1 of every 3 cycles (i.e., every 
9 weeks±7 days) through 15 cycles, Cycle 17 and every 6 cycles thereafter 
until PD or end of study treatment. Not applicable prior to PACT (included in 
Amendment 10). 
• Post-treatment: For participants who discontinue treatment, HRQoL 
assessments should be collected at the end of treatment (EOT) Visit, 30-day 
post EOT (±7 days) Safety Follow-up Visit, 90-day post EOT (±14 days) 
Long-Term Follow-up Visit, and every 180 days (±14 days) after the Long-
Term Follow-up Visit (every other post-treatment assessment beginning on 
post-treatment assessment), which will continue until death or the end of study 
data collection. Not applicable prior to PACT (included in Amendment 10). 
All HRQoL assessments during the Chemotherapy Treatment and Maintenance Periods 
should be collected in clinic, on the day of study drug administration, prior to dosing or 
clinical procedures. They may be completed remotely if the participant is no longer 
actively returning to the site. 
Biomarker Assessment 
Pharmacokinetic/Immunogenicity Assessment 
PK blood samples will be collected for dostarlimab and niraparib (Table 19 and Table 20, 
respectively) for evaluation from all sites. Serum and plasma samples generated for 
dostarlimab and niraparib PK evaluation will be based on a 
 
  
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Niraparib PK will be collected in the Maintenance Treatment Period only. To allow for 
hematologic toxicity recovery (approximately 6 to 9 weeks), participants will begin 
niraparib dosing at Cycle 2 or Cycle 3 of the Maintenance Treatment Period, and 
niraparib PK sampling will start accordingly on Day 1 as follows: 
Cycle 2 niraparib start: Niraparib PK samples drawn on Cycle 2, Cycle 3, Cycle 7, and 
Cycle 9. 
Cycle 3 niraparib start: Niraparib PK samples drawn on Cycle 3, Cycle 7, and Cycle 9. 
 samples are the aliquots of PK sample collections and will be 
collected for 
 only (Table 19).
 will be evaluated through 
 (Screening, confirmatory, and titer), as well as 
 
 (Not applicable per Amendment 10).  
PACT Phase 
Following the final analysis DCO date, the study may move into the PACT phase (see 
Section 5.6 for details). Participants who continue to receive study treatment during the 
PACT phase will be monitored for safety (see Section 8.2) and will receive follow-up 
care in accordance with standard local clinical practice. Assessments will revert to the 
standard of care at a participant’s particular study site. Study treatment will continue for 
up to 3 years from the final DCO date, or until transition to an alternative method of 
continued treatment access (outside of the study), or manufacturing of the product ceases, 
or the study intervention discontinuation criteria are met (Section 4.3.1), whichever 
occurs first. Alternative continued treatment access outside of this study may be 
implemented, as it becomes available. 
End of Treatment Visit and Safety Follow-up Visit 
All participants will undergo an EOT visit within 7 days after the last dose of study 
treatment or at the time of disease progression, whichever occurs first. A safety follow-up 
visit will be conducted 30 days (±7 days) after the last dose of the last study treatment or 
before the initiation of follow-up anticancer therapy. Safety follow-up visits are required 
only for those participants who have not started follow-up anticancer therapy. After the 
30-day (±7 days) safety follow-up visit, all participants will enter the post-treatment 
follow-up period of telephone assessment for survival status, documentation and 
management of any AEs/SAEs, adverse events of special interest (AESIs), and follow-up 
anticancer therapy every 90 (±14 days) until participant discontinuation of study, 
withdrawal of consent, or death. 
 
 If a participant 
discontinues treatment within 28 days of the scan that indicates PD, then the EOT scan 
will not be performed.  
Refer to schedule of events (Table 16) for adjustments to End of Treatment Visit and 
Safety Follow-up visits prior to PACT. 
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Following the local implementation of Amendment 10, the study will conclude all post-
treatment long-term follow-up data collection beyond 90 days (±14 days) after the last 
dose of study treatment (or for a minimum of 30 days post-treatment discontinuation if 
the participant starts alternative anticancer therapy or no follow-up data collection is 
required for the study if the participant transitions to continue the treatment outside of the 
study). After the 30-day (±7 days) safety follow-up visit, there will be only one post-
treatment follow-up assessment for SAE and AESIs at 90 days following the last dose of 
study treatment.  
A safety follow-up visit is not carried out for a participant who transitions to continue 
treatment outside of the study prior to PACT (see Section 5.5).  
For a participant discontinuing treatment in the PACT phase, no end of treatment or 
safety follow-up visit is required.   
Safety Assessments 
Safety assessments conducted throughout the Chemotherapy Treatment Period and 
Maintenance Treatment Period include collection of TEAEs, serious adverse events 
(SAEs), treatment discontinuations or dose delays or reductions due to AEs, ECOG 
performance, clinical laboratory results (hematology and chemistry), vital sign 
measurements, observations during physical examination, and use of concomitant 
medications.  
AEs are required to be captured through 30 days after cessation of study treatment; SAEs 
are required to be captured through 90 days after cessation of study treatment (or for a 
minimum of 30 days post-treatment discontinuation if the participant starts alternative 
anticancer therapy); and any pregnancies that occur within 180 days post-treatment 
discontinuation are to be captured. Once the specified safety reporting period has elapsed 
, if the Investigator learns of an AESI or an SAE that is considered reasonably related to 
the study intervention or study participation, the Investigator must promptly notify the 
Sponsor. All AEs and SAEs experienced by a participant, regardless of the suspected 
causality, will be monitored until the AE or SAE has resolved, until any abnormal 
laboratory values have returned to baseline or normalized, until there is a satisfactory 
explanation for the change(s) observed, until the participant is lost to follow-up or 
withdraws consent, or until the participant has died. 
The niraparib AESIs for this study are myelodysplastic syndrome (MDS), acute myeloid 
leukemia (AML), secondary cancers (new malignancies other than MDS/AML). There 
are no AESIs for dostarlimab. AESIs must be reported to the Sponsor as soon as the 
Investigator becomes aware of them. 
For PACT, SAEs, AEs leading to study intervention discontinuation, AESI, pregnancy, 
and overdose cases will be reported, as outlined in Section 8.2. 

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3.7. 
End-of-Study Definition 
A final DCO representing the end of data collection, prior to EOS, is defined as the DCO 
date for the final analysis. Following the final DCO date, the study may move into the 
PACT phase and the clinical study database will be closed to new data. Participants who 
have not transitioned to continue treatment access outside of the study at the time at final 
DCO who are receiving study treatment may continue, as described in Section 5.5, to 
receive niraparib and/or dostarlimab if they are deriving clinical benefit as assessed by 
the Investigator. Although the clinical study database will be closed to new data, the 
study will remain open until all participants discontinue study treatment and the EOS 
definition is reached.  
The EOS is defined as the date of the Last Subject Last Visit (LSLV; defined as the date 
of the last subject to complete the study [i.e., assessments as defined in the Schedule of 
Events or last dose plus, if applicable, 90 day AE reporting period]).  

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4. 
SELECTION AND WITHDRAWAL OF PARTICIPANTS 
4.1. 
Participant Inclusion Criteria 
To be considered eligible to participate in this study the following requirements must be 
met: 
1. Participants must be female, ≥18 years of age, able to understand the study 
procedures, and agree to participate in the study by providing written informed 
consent. 
2. Participants with a histologically confirmed diagnosis of high-grade nonmucinous 
epithelial ovarian (serous, endometrioid, clear cell, carcinosarcoma, and mixed 
pathologies), fallopian tube, or peritoneal cancer that is Stage III or IV according 
to the FIGO or tumor, node and metastasis staging criteria [i.e., American Joint 
Committee on Cancer]. 
3. All participants with Stage IV disease are eligible. This includes those with 
inoperable disease, those who undergo PDS (R0 or macroscopic disease), or those 
for whom NACT is planned. 
4. Participants with Stage III are eligible if they meet one or more of the following 
criteria: 
a. Stage IIIC participants with CC0 resection if they meet the following 
criteria: Aggregate ≥5 cm extra-pelvic disease during PDS as assessed by the 
Investigator. 
b. All participants with inoperable Stage III disease. 
c. All Stage III participants with macroscopic residual tumor (per Investigator 
judgment) following PDS. 
d. All Stage III participants for whom NACT is planned. 
5. Participants must provide a blood sample for 
 testing at Pre-
Screening or Screening.  
6. Participant must provide 
 
  
7. Participants of childbearing potential must have a negative serum or urine 
pregnancy test (beta human chorionic gonadotropin) within 3 days prior to 
receiving the first dose of study treatment. 
8. Participants must be postmenopausal, free from menses for >1 year, surgically 
sterilized, or willing to use highly effective contraception to prevent pregnancy 
(see Appendix 3) or must agree to abstain from activities that could result in 
pregnancy throughout the study, starting with enrollment through 180 days after 
the last dose of study treatment. 
9. Participants must have adequate organ function, defined as follows (Note: CBC 
test should be obtained without transfusion or receipt of stimulating factors within 
2 weeks before obtaining Screening blood sample): 
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a. ANC ≥1,500/µL 
b. Platelet count ≥100,000/µL 
c. Hemoglobin ≥9 g/dL 
d. Serum creatinine ≤1.5×upper limit of normal (ULN) or calculated creatinine 
clearance ≥60 mL/min using the Cockcroft-Gault equation 
e. Total bilirubin ≤1.5×ULN or direct bilirubin ≤1.5×ULN 
f. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) 
≤2.5×ULN unless liver metastases are present, in which case they must be 
≤5×ULN 
10. Participants must have an ECOG score of 0 or 1. 
11. Participants must have normal BP or adequately treated and controlled 
hypertension (systolic BP ≤140 mmHg and/or diastolic BP ≤90 mmHg). 
12. Participants must agree to complete HRQoL questionnaires throughout the study. 
13. Participants must be able to take oral medication. 
4.2. 
Participant Exclusion Criteria 
Participants will not be eligible for study entry if any of the following criteria are met: 
1. Participant has mucinous, germ cell, transitional cell, or undifferentiated tumor.  
2. Participant has low-grade or Grade 1 epithelial ovarian cancer. 
3. Stage III participant with CC0 resection after PDS (i.e., no macroscopic residual 
disease, unless inclusion criterion #4a is met). 
4. Participant has not adequately recovered from prior major surgery. 
5. Participant has a known condition, therapy, or laboratory abnormality that might 
confound the study results or interfere with the participant’s participation for the 
full duration of the study treatment in the opinion of the Investigator. 
6. Participant is pregnant or is expecting to conceive children while receiving study 
drug or for up to 180 days after the last dose of study drug. Participant is 
breastfeeding or is expecting to breastfeed within 30 days of receiving the final 
dose of study drug (women should not breastfeed or store breastmilk for use, 
during niraparib treatment and for 30 days after receiving the final dose of study 
treatment). 
7. Participant has known active central nervous system metastases, carcinomatous 
meningitis, or both.  
8. Participant has clinically significant cardiovascular disease (e.g., significant 
cardiac conduction abnormalities, uncontrolled hypertension, myocardial 
infarction, uncontrolled cardiac arrhythmia or unstable angina <6 months to 
enrollment, New York Heart Association Grade 2 or greater congestive heart 
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peripheral vascular disease, and history of cerebrovascular accident within 
6 months). 
9. Participant has a bowel obstruction by clinical symptoms or CT scan, 
subocclusive mesenteric disease, abdominal or gastrointestinal fistula, 
gastrointestinal perforation, or intra-abdominal abscess.  
10. Participant initiating bevacizumab as SOC has proteinuria as demonstrated by 
urine protein:creatinine ratio ≥1.0 at Screening or urine dipstick for proteinuria 
≥2 (participants discovered to have ≥2 proteinuria on dipstick at baseline should 
undergo a 24-hour urine collection and must demonstrate <2 g of protein in 
24 hours to be eligible). 
11. Participant has any known history or current diagnosis of MDS or AML. 
12. Participant has been diagnosed and/or treated with any therapy for invasive cancer 
<5 years from study enrollment, completed adjuvant chemotherapy and/or 
targeted therapy (e.g., trastuzumab) less than 3 years from enrollment, or 
completed adjuvant hormonal therapy less than 4 weeks from enrollment. 
Participants with definitively treated non-invasive malignancies such as cervical 
carcinoma in situ, ductal carcinoma in situ, Grade 1 or 2, Stage I endometrial 
cancer, or non-melanomatous skin cancer are allowed.  
13. Participant is at increased bleeding risk due to concurrent conditions (e.g., major 
injuries or major surgery within the past 28 days prior to start of study treatment 
and/or history of hemorrhagic stroke, transient ischemic attack, subarachnoid 
hemorrhage, or clinically significant hemorrhage within the past 3 months). 
14. Participant is immunocompromised. Participants with splenectomy are allowed. 
Participants with known human immunodeficiency virus (HIV) are allowed if 
they meet all of the following criteria: 
a. Cluster of differentiation 4 ≥350/µL and viral load <400 copies/mL 
b. No history of acquired immunodeficiency syndrome–defining opportunistic 
infections within 12 months prior to enrollment 
c. No history of HIV-associated malignancy for the past 5 years 
d. Concurrent anti-retroviral therapy as per the most current National Institutes 
of Health (NIH) Guidelines for the Use of Anti-retroviral Agents in Adults 
and Adolescents Living with HIV started >4 weeks prior to study enrollment 
[US Department of Health and Human Services, 2017].  
15. Participant has known active hepatitis B (e.g., hepatitis B surface antigen reactive) 
or hepatitis C (e.g., hepatitis C virus ribonucleic acid [qualitative] is detected). 
16. Participant is considered a poor medical risk due to a serious, uncontrolled 
medical disorder, non-malignant systemic disease, or uncontrolled infection. 
Specific examples include, but are not limited to, history of non-infectious 
pneumonitis that required steroids, current pneumonitis, uncontrolled autoimmune 
disease, uncontrolled ventricular arrhythmia, recent myocardial infarction within 
90 days of consent, uncontrolled major seizure disorder, unstable spinal cord 
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disorders that would interfere with cooperation with the requirements of the study 
(including obtaining informed consent). 
17. Participant has had investigational therapy administered within 4 weeks or within 
a time interval less than at least 5 half-lives of the investigational agent, 
whichever is longer, prior to the first scheduled day of dosing in this study. 
18. Participant has received a live vaccine within 14 days of planned start of study 
therapy. Seasonal influenza vaccines that do not contain live viruses are allowed. 
19. Participant has a known contraindication or uncontrolled hypersensitivity to the 
components of paclitaxel, carboplatin, niraparib, bevacizumab, dostarlimab, or 
their excipients. 
20. Prior treatment for high-grade nonmucinous epithelial ovarian, fallopian tube, or 
peritoneal cancer (immunotherapy, anticancer therapy, radiation therapy). 
21. Participant has an active autoimmune disease that has required systemic treatment 
in the past 2 years. Replacement therapy is not considered a form of systemic 
therapy (e.g., thyroid hormone or insulin). 
22. Participant has a diagnosis of immunodeficiency or is receiving systemic steroid 
therapy or any other form of systemic immunosuppressive therapy within 7 days 
prior to the first dose of study treatment. 
4.3. 
Participant Withdrawal Criteria 
4.3.1. 
Discontinuation from Treatment 
Participants may be discontinued from study treatment at any time. Participants who 
discontinue from study treatment will not be replaced. Participants who discontinue from 
the final study treatment will attend the EOT visit within 7 days after the last dose of 
study treatment, followed by the 30-day (±7 days) Safety Follow-up Visit. End of 
treatment is described as within 7 days after discontinuation of the last study treatment. 
Safety Follow-up Visit and the post-treatment, long-term follow-up period include OS 
assessment.  
Following the local implementation of Amendment 10, the study will conclude all post-
treatment long-term follow-up data collection beyond 90 days (±14 days) after the last 
dose of study treatment (or for a minimum of 30 days post-treatment discontinuation if 
the participant starts alternative anticancer therapy, or no follow-up data collection is 
required for the study if the participant transitions to continue the treatment outside of the 
study). A participant’s most recent long-term follow-up visit, which is greater than or 
equal to 90 days (±14 days) post-treatment (if applicable), before Amendment 10 
becomes effective, will be recognized as the participant’s final follow-up visit. 
Specific reasons for discontinuing treatment include the following, in addition to those 
indicated in Section 3.4: 

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• AE 
− If a participant has any treatment-related National Cancer Institute - 
Common Terminology Criteria for Adverse Events (NCI-CTCAE) v4.03 
Grade 3 or 4 AEs (see Table 11 separate guidelines for platelet count) that 
have not reverted to NCI-CTCAE v4.03 Grade 1 or better within 28 days. 
− If upon re-challenge with study treatment at the lowest allowable dose any 
NCI-CTCAE v4.03 Grade 3 or 4 AEs recur, the participant must be 
discontinued from niraparib treatment. 
− AEs as defined per protocol (Table 10 and Table 11). 
• In the case of thrombocytopenia, if the platelet count has not returned to 
≥100,000/µL within 28 days of dose interruption. 
• If the participant has disease progression according to RECIST v1.1 criteria by 
Investigator. 
• If the participant has disease progression according to clinical criteria of 
histology/cytology confirmed PD in the absence of radiographic progression 
• If there is risk to the participant as judged by the Investigator, Sponsor, or 
both. 
• If the participant has had severe non-compliance with protocol as judged by 
the Investigator, Sponsor, or both. 
• If the participant becomes pregnant. 
• If the participant decides to discontinue study treatment. Note: Participant 
should continue in long term study follow up. For a participant discontinuing 
treatment in the PACT phase, no end of treatment or follow-up visits are 
required. 
• If the participant is lost to follow-up. 
• If the participant dies. 
• PACT phase: 3 years of study treatment administration have been completed 
following final DCO date. 
4.3.2. 
Withdrawal of Consent 
If a participant considers withdrawal of consent, the Investigator is to determine whether 
the participant is willing to be followed up for subsequent procedures in the long-term 
follow-up period and for OS. Such participants will be required to indicate whether they 
agree to continue these procedures and to use of the blood and tumor samples they 
provided for the study for research purposes; the latter information will be recorded on 
the appropriate eCRF page. Survival status will be collected for participants who 
withdraw consent using acceptable means, including public records where allowed, per 
local regulations. The post-treatment, long-term follow-up period will continue until 
Amendment 10 is locally effective; the study will be closed for further post-treatment 
long-term follow-up data collection (refer to Section 4.3.1 for further details).  

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4.3.2.1. 
Further Research Maintaining Confidential Participant Information 
The Sponsor may conduct further research on specimens collected during this study. 
 
 
 
 
In an effort to optimize the research that can be conducted with further research 
specimens, it is essential to link study participant clinical study data with further research 
test results. The clinical study data allow specific analyses to be conducted. Knowing 
participant characteristics like gender, age, medical history, treatment type, and treatment 
outcomes are critical to understanding the clinical context of further research analytical 
results. 
To maintain privacy of information collected from specimens obtained for further 
research, the Sponsor has developed secure policies and procedures. All specimens will 
be single coded per ICH E15 guidelines, “Definitions for Genomic Biomarkers, 
Pharmacogenomics, Pharmacogenetics, Genomic Data and Sample Coding Categories” 
[ICH Harmonised Tripartite E15, 2007]. 
At the clinical study site, unique codes will be placed on further research specimens for 
transfer to the storage facility. This first code is a random number that does not contain 
any personally identifying information embedded within it in order to maintain 
participant privacy. The link (or key) between participant identifiers and this first unique 
code will be held at the study site. No personal identifiers will appear on the specimen 
tube. 
Documentation of participant life-time consent for further research will be captured in the 
eCRFs. Any specimens for which such an informed consent cannot be verified will be 
destroyed, as will those requested to be destroyed at time of consent withdrawal. 
Participants may withdraw their consent for further research and have their specimens 
and all derivatives destroyed. Participants may withdraw their consent at any time by 
contacting the Investigator. 
4.3.3. 
Discontinuation from the Study 
Participants may be discontinued from the study for any of the following reasons: 
• Withdrawal of consent by the participant, who is at any time free to 
discontinue participation in the study, without prejudice to further treatment 
• Lost to follow up 
• Death from any cause 
• Sponsor decision to terminate study 
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If a participant is thought to be lost to follow-up or discontinues the study, attempts 
should be made to contact the participant to determine the reason for discontinuation. For 
participants who are thought to be lost to follow-up, at least 3 documented attempts over 
6 months, including 1 attempt via certified mail or local equivalent methods, should be 
made to contact the participant before the participant is deemed lost to follow-up. These 
contact attempts should be documented in the participant’s medical record. 
Site personnel, or a trusted independent third party, should attempt to collect the vital 
status of the participant within legal and ethical boundaries for all participants 
randomized. Public sources may be searched for vital status information. If vital status is 
determined as deceased, this will be documented. Sponsor personnel will not be involved 
in any attempts to collect vital status information. 
The Sponsor will notify the Investigators when the study is to be placed on hold, 
completed, or terminated. Per Investigator discretion and in consultation with the 
Sponsor, participants who are still receiving and benefiting from study treatment may 
have an option to continue to receive study treatment. 

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5. 
TREATMENT OF PARTICIPANTS 
5.1. 
Description of Study Drug 
Details about the investigational products are provided in Table 13. Following the 
analysis (DCO 31 October 2024), prior to PACT, participants ongoing on study drugs are 
to be centrally unblinded and placebo administration discontinued (i.e., Arm 1 niraparib 
placebo and/or dostarlimab placebo [not previously unblinded according to Amendment 
4] and Arm 2 dostarlimab placebo). Arm 1 participants will be discontinued from the 
study following niraparib placebo and/or dostarlimab placebo discontinuation. 
Table 13: 
Investigational Products 
 
Investigational Products 
Product name 
Niraparib/placeboa 
Nirapariba 
Dostarlimab/placebo 
Dosage form 
Unit dose 
Route of 
administration 
Oral 
Oral 
Intravenous 
Physical 
description 
a All participants in Arm 1 only who were previously randomized to placebo and are not receiving 
bevacizumab will be unblinded and provided the option to receive niraparib maintenance if they have 
received chemotherapy or discontinued chemotherapy ≤12 weeks. 
b Transition from 
 form anticipated during the PACT phase of the study. 
For PACT, niraparib (capsule/tablet) and dostarlimab will be open-label. 
5.2. 
Concomitant Medications 
Any medication the participant takes other than the study treatment, including herbal and 
other non-traditional remedies, is considered a concomitant medication. All concomitant 
medications must be recorded in the eCRF. The following information must be recorded 
in the eCRF for each concomitant medication: generic name, route of administration, start 
date, stop date, dosage, and indication. Any changes in the dosage or regimen of a 
concomitant medication must be recorded in the eCRF. 
At Screening, participants will be asked what medications they have taken during the last 
30 days. At each subsequent study visit, participants will be asked what concomitant 
medications they are currently taking.  
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5.2.1. 
Prohibited Medications 
Known prior medications that exclude a participant from participating in the study are 
described in the exclusion criteria (Section 4.2). 
Participants are prohibited from receiving the following therapies during the Screening 
and treatment phase of this study: 
• Systemic anticancer or biological therapy 
• Immunotherapy not specified in this protocol 
• Chemotherapy not specified in this protocol 
• Investigational agents other than niraparib and dostarlimab 
• Live vaccines within 14 days prior to the first dose of study treatment. Seasonal 
flu vaccines that do not contain live viruses are allowed.  
• COVID-19 vaccine within 14 days prior to the first dose of dostarlimab. 
An increased risk of infection by the administration of live virus and bacterial vaccines 
has been observed with conventional chemotherapy drugs. Effects with niraparib are 
unknown; therefore, live virus and bacterial vaccines should not be administered to 
participants in the study. 
No other anticancer therapy is permitted during the course of the study treatment for any 
participant. Palliative radiotherapy (excluding the pelvic region and/or palliative 
radiotherapy encompassing >20% of the bone marrow within 1 week of the first dose of 
study treatment) is allowed for pre-existing small areas of painful metastases that cannot 
be managed with local or systemic analgesics, as long as no evidence of disease 
progression is present. 
Systemic glucocorticoids for any purpose other than to manage symptoms of suspected 
irAEs. (Note: Use of inhaled steroids, local steroid injection, topical steroids, and steroid 
eye drops are allowed). If medically deemed necessary (e.g., acute asthma, or chronic 
obstructive pulmonary disease exacerbation, prophylaxis for IV contrast if indicated), 
Investigators are allowed to use their judgment to treat participants with systemic 
steroids. In such cases, systemic steroids should be stopped at least 24 hours prior to the 
next dose of study treatment. Note: corticosteroids used for premedication for 
chemotherapeutic agents specified in the protocol are allowed. 
The niraparib safety profile includes risk for thrombocytopenia, and bevacizumab may 
increase the potential for bleeding (hemorrhage); therefore, participants should be 
advised to use caution when taking anticoagulants (e.g., warfarin) and antiplatelet drugs 
(e.g., aspirin). 
Niraparib has the potential to weakly induce cytochrome P450 (CYP) 1A2. Therefore, 
participants and Investigators are advised to use caution with drugs that are substrates of 
CYP1A2 with narrow therapeutic range, such as theophylline and tizanidine. 

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Physicians should follow the current versions of the niraparib IB, local practice 
guidelines and package inserts for carboplatin, paclitaxel, and bevacizumab, and the 
dostarlimab IB for information on the general management of the participants receiving 
these therapies. 
5.3. 
Treatment Compliance 
Compliance with inclusion and exclusion criteria will be assessed as outlined in 
Section 4.1 and Section 4.2, respectively. 
Study treatment (paclitaxel-carboplatin, niraparib, bevacizumab, and dostarlimab) will be 
administered by site personnel at study sites as detailed in Section 6.5. 
Study drug accountability will be monitored as detailed in Section 6.6. 
5.4. 
Randomization and Blinding 
5.4.1. 
Participant Identification 
All participants who enter into the Pre-Screening period of the study (defined as the point 
at which the participant signs the Pre-Screening ICF) will receive a unique participant 
identification number. This number will be used to identify the participant throughout the 
study and must be used on all study documentation related to that participant. A 
participant will be considered enrolled when the participant has consented and been 
screened, and when all eligibility criteria have been confirmed in the eCRF. The 
participant identification number must remain constant throughout the entire study; it 
must not be changed at the time of enrollment. 
5.4.2. 
Randomization Scheme 
5.4.3. 
Blinding and Breaking the Blind 
The participant, Investigator, Blinded Study Staff, the Blinded Sponsor study team and its 
representatives will be blinded to the 
 and assigned treatment. An 
unblinded study team consisting of, at a minimum, a site Pharmacist, back-up 
Pharmacist, and Sponsor Monitor will keep confidential the treatment assignment of 
each participant and will dispense the study medication, retain and monitor the drug 
accountability records for the trial. 
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If an individual’s role on the trial requires information about treatment assignment (e.g., 
an individual is involved in emergency unblinding), procedures will be used to ensure all 
other personnel remain blinded.  
The identity of the treatments will be concealed by the use of study treatments that are all 
identical in appearance, packaging, labeling, and schedule of administration. 
 
 
 For PACT, niraparib 
 and dostarlimab 
will be open-label. 
Treatment assignment may be unblinded for urgent or non-urgent clinical reasons as 
determined by the Investigator. The Sponsor’s guidance regarding unblinding is as 
follows: the participant has confirmed disease progression as defined by the protocol 
(Section 7.1) and knowledge of experimental therapy may guide future treatment or 
treatment decisions for the participant in the case of an emergency medical event (as 
assessed by the treating physician). Participants who require unblinding of treatment 
assignment will be permanently discontinued from study treatment but will continue to be 
followed unless the participant withdraws consent. 
The primary source for unblinding is the RaveX RTSM (formerly known as iMedidata 
Balance). Unblinding through RaveX RTSM can only be performed by individuals with 
the role of “Investigator blinded - can unblind,” typically the Investigator and/or other 
limited medically qualified personnel deemed appropriate by the Investigator. The Help 
Desk is the secondary source for unblinding when RaveX RTSM is either not accessible 
by the primary Investigator or when an alternate qualified medical representative needs 
immediate access to treatment information. Additional information on the process for 
unblinding the identity of the assigned treatment is outlined in the Pharmacy Manual. 
Following implementation of Amendment 4, Arm 1 participants receiving bevacizumab 
will remain blinded. Arm 1 participants not receiving bevacizumab will be unblinded 
centrally by the Sponsor and a communication will be sent to the investigative site 
unblinding the participants and indicating the treatment groups as outlined in 
Appendix 11. 
5.4.3.1. 
Unblinding Post Analysis (31 October 2024, Prior to PACT) 
The Sponsor may choose to initiate unblinding of Investigators to participants' study 
treatment assignment prior to PACT, or if the study is concluding or closure is initiated. 
Participants receiving niraparib and/or dostarlimab might continue with their treatment 
until a post-trial treatment outside of the study is in place, or continue into the PACT 
phase if treatment is not available and accessible, as outlined in Sections 5.5 and 5.6. The 
investigator may contact the medical monitor to discuss the participant's decision on their 
study treatment. Investigators may also request a participant's HRD status (if available) to 
determine post-trial niraparib treatment access in the participant's country, if relevant. 
The study may be centrally unblinded prior to PACT, at which point randomization codes 
and treatment assignments will be provided to the investigators. Following the analysis 
(DCO 31 October 2024), the study Sponsor team was unblinded to the participants' HRD 
status (if available) and their assigned treatments, encompassing both placebo and active 
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drug groups. This unblinding was necessary to effectively manage ongoing participant 
care and plan for post-trial continued treatment access. 
For participant management following the analysis (DCO 31 October 2024), prior to 
PACT, participants ongoing on study drugs are to be centrally unblinded and dostarlimab 
placebo administration is to be discontinued (i.e., Arm 1 niraparib placebo and/or 
dostarlimab placebo [not previously unblinded according to Amendment 4] and Arm 2 
dostarlimab placebo). Arm 1 participants will be discontinued from the study following 
niraparib placebo and/or dostarlimab placebo discontinuation. Participants in Arm 2 and 
Arm 3 receiving active treatments, such as niraparib and/or dostarlimab, and centrally 
unblinded will not be discontinued from study treatment. These participants will be 
allowed to either continue with the study drug during the PACT phase or transition out of 
the study once treatment access becomes available and accessible, either before or during 
PACT, if applicable. 
5.5. 
Continued Access to Study Intervention After the End of the 
Study 
The investigator is responsible for ensuring that consideration has been given to the post-
trial care of the participants’ medical condition, whether or not GSK is providing specific 
post-trial provision. 
The study remains open until all participants discontinue study treatment and the EOS 
definition is reached (see Section 3.7). Prior to PACT,  participants who would continue 
to benefit and who have an acceptable tolerability profile to access niraparib and/or 
dostarlimab, if eligible, at the discretion of the treating physician and patient, excluding if 
there are safety concerns, may transition by the final DCO to continue treatment outside 
of the study protocol (if available). If the product(s) is/are not commercially available and 
accessible, participants may transition to either a rollover study, Managed Access route, 
or other potential mechanism of access. The selection of continued treatment access route 
will be according to availability in the participant’s country and as permitted by local 
regulations. During the PACT phase, alternative continued treatment access route outside 
of this study may be implemented, as it becomes available. 
For a Managed Access mechanism, if applicable, access will be given to eligible 
participants if the treating physician confirms that criteria are met (such as, a positive 
benefit-risk ratio and that there is no comparable or suitable alternative therapy available) 
and submits an explicit request to GSK for assessment. Niraparib and/or dostarlimab may 
be provided for a minimum of 3 years, or until the intervention becomes commercially 
available and accessible in the participant’s country, or until manufacturing of the 
product ceases, whichever occurs first.  
In a rollover study, if applicable, participants will be followed for safety and continue 
until treatment discontinuation criteria are met or according to the duration of the rollover 
study remaining at the time of transition, whichever occurs first.  

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Safety follow-up visits should be conducted (see Section 8.2) if the participant 
discontinues study treatment and does not continue niraparib and/or dostarlimab by a 
post-trial access route. Following such visits, the participant will have completed the 
study. 
5.6. 
Continued Access to Study Intervention After Data Cut-off 
Prior to EoS  
Following the DCO date for the final analysis, Study 213350 (FIRST) may move into the 
PACT phase. Participants receiving dostarlimab and/or niraparib at the time of the final 
analysis DCO date may continue to receive dostarlimab and/or niraparib if, in the opinion 
of their treating physician, they are clinically benefiting from continued treatment, they 
do not meet any protocol-defined treatment discontinuation criteria (Section 4.3.1) and 
the Sponsor is notified. Study treatment will continue for up to 3 years from the final 
DCO date (Section 4.3.1), or until transition to an alternative method of continued 
treatment access outside of the study (Section 5.5), or until manufacturing of the product 
ceases, or until a study intervention discontinuation criterion (Section 4.3.1), as assessed 
by the Investigator, has been met, whichever occurs first. Alternative continued treatment 
access outside of this study may be implemented, as it becomes available. 
Participants who continue niraparib and/or dostarlimab in the PACT phase will be cared 
for in accordance with local standard clinical practice. Additional guidance on treatment 
with the study intervention and participant management is provided in the Pharmacy 
manual and Section 6. 
Participants will continue to be monitored for all SAEs, AEs leading to study intervention 
discontinuation, overdoses, AESIs, and pregnancy while receiving niraparib and/or 
dostarlimab and these events must continue to be reported to the sponsor in accordance 
with Section 8.2. Information relating to participant care will be recorded on participant 
medical records but will not be reported for the purposes of this study.  
For dispensing of study intervention and maintaining study intervention accountability in 
the PACT phase, please refer to the Pharmacy Manual. All other assessments will revert 
to standard of care at their site. 
 

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6. 
STUDY DRUG MATERIALS AND MANAGEMENT 
Study drugs and their product family roles are defined below. 
Study Drug 
Product Family Role 
Bevacizumab 
AxMP 
Carboplatin 
AxMP 
Paclitaxel 
AxMP 
Dostarlimab 
IMP 
Niraparib 
IMP 
6.1. 
Study Drug 
6.1.1. 
Niraparib 
 is an orally available, potent, and highly selective PARP1 and PARP2 
inhibitor. 
 
 
 
 
. 
6.1.2. 
Dostarlimab 
Dostarlimab is an 
 
 
6.2. 
Study Drug Packaging and Labeling 
The label text of the study treatments will comply with Good Manufacturing Practice. 
The niraparib study treatment will be labeled in a blinded fashion. The site will be 
provided open-label dostarlimab, and the unblinded pharmacist will prepare the 
appropriate drug or placebo for administration. Carboplatin [Carboplatin Injection, 2023; 
CARBOplatin Injection BP, 2022], paclitaxel [Paclitaxel Injection Multidose Vial, 2023; 
Paclitaxel Powder for Injectable Suspension Nanoparticle, 2021], and bevacizumab 
[AVASTIN®, 2016; ZIRABEV- bevacizumab injection, 2023] are described in their 
respective prescribing information. 
For PACT, niraparib (capsule/tablet) and dostarlimab will be open-label. 
6.3. 
Study Drug Storage 
All study treatment supplies must be stored in accordance with the Pharmacy Manual 
instructions and package labeling. Until dispensed or administered to the participants, the 
study treatment will be stored in a securely locked area that is accessible only to 
authorized personnel. 
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6.4. 
Study Drug Preparation 
The Pharmacy Manual contains specific instructions for the preparation of each dose of 
the dostarlimab infusion solution. 
6.5. 
Order of Study Drug Administration 
It is recommended that drugs be administered starting with 
 The recommended order of administration is provided 
below, unless local clinical practice or institutional policies differ:  
• During the Chemotherapy Treatment Period, 
 
 
  
• During the Maintenance Treatment Period, 
 
 
6.5.1. 
Investigational Medicinal Products 
6.5.1.1. 
Niraparib 
Participants who do not have PD on chemotherapy and with recovery to baseline 
(pre-randomization) of hematologic toxicities will enter the Maintenance Treatment 
Period. Oral niraparib placebo (Arm 1) or niraparib (Arms 2 and 3) will be dispensed to 
participants on Day 1 of Q21D cycle beginning with Cycle 2 or Cycle 3 of the 
Maintenance Treatment Period for up to 3 years, in the absence of PD, unacceptable 
toxicity, or participant withdrawal, or based on Investigator’s decision. Participants who 
continue to derive benefit from study treatment based on continuation of best overall 
response indicated by imaging, remain clinically stable, and are willing to continue study 
visits and assessments may continue to receive niraparib and/or dostarlimab/placebo 
beyond 3 years following consultation with the investigator and the Sponsor. 
On Day 1 of each applicable cycle, niraparib will be administered upon completion of 
bevacizumab or dostarlimab infusion; the first dose will be administered at the study site.  
The starting dose of niraparib will be based on the participant’s actual body weight and 
platelet count (Table 14) as measured prior to dosing in the Maintenance Treatment 
Period. Participants with an actual body weight of ≥77 kg and a platelet count of 
≥150,000/μL will 
 at each dose 
administration. Participants with an actual body weight of <77 kg, a platelet count of 
<150,000/μL, or both will take 
 at each 
dose administration. Dose modifications will not be based upon changes in the 
participant’s actual body weight during study participation (see Section 3.4). 
For participants whose starting dose is 
, escalation to 
 is permitted if no treatment interruptions or 
discontinuations were required during the first 2 cycles of therapy. This escalation will 
occur at the discretion of the Investigator, following discussion with the Sponsor. 
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Table 14: 
Recommended Initial Starting Dose 
Baseline Criteria 
Starting Dose 
≥77 kg and ≥150,000/μL 
<77 kg OR <150,000/μL OR both 
Participants will be instructed to take their niraparib dose
 at approximately the same 
time each day. Participants must swallow and not chew all
. The 
consumption of water and food with 
 is permissible. If a participant 
vomits or misses a dose of niraparib, a replacement dose should not be taken.  
Details on the administration of niraparib can be found in the Pharmacy Manual. 
6.5.1.2. 
Dostarlimab 
During the Chemotherapy Treatment Period, dostarlimab/placebo 
 will be 
administered at the study site via a 
 on Day 1 of 
Q21D cycle. Dostarlimab/placebo will be started with Cycle 2 of chemotherapy and does 
not need to be held prior to or following major surgery. 
Dostarlimab/placebo±bevacizumab will continue from the Chemotherapy Treatment 
Period through the Maintenance Treatment Period. 
During the Maintenance Treatment Period, dostarlimab/placebo
 will be 
administered via a 
 on Day 1 of every other cycle (every 6 weeks). 
At the time of disease progression, dostarlimab treatment will be unblinded and treatment 
with IV dostarlimab/placebo will be discontinued.  
Participants who continue to derive benefit from study treatment based on continuation of 
best overall response indicated by imaging, remain clinically stable, and are willing to 
continue study visits and assessments may continue to receive niraparib and/or 
dostarlimab/placebo beyond 3 years following consultation with the investigator and the 
Sponsor. 
Details on the administration of dostarlimab/placebo can be found in the Pharmacy 
Manual. 
6.5.2. 
Non-Investigational Medicinal Products 
6.5.2.1. 
Bevacizumab 
For participants in all 3 Arms, during the Chemotherapy Treatment Period, optional 
bevacizumab 7.5 mg/kg or 15 mg/kg may be administered at the study site via a 90-
minute IV infusion on Day 1 of Q21D cycle. The initial dose of bevacizumab will be 
delivered over 90 (±15) minutes. If the first infusion is tolerated without infusion-
associated AEs (fever and/or chills), the second infusion may be delivered over 60 (±10) 
minutes. If the 60-minute infusion is well tolerated, all subsequent infusions may be 
delivered over 30 (±10) minutes.  
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Participants undergoing PDS or IDS may be administered bevacizumab as SOC (per local 
practice) during Cycles 1 to 6. After PDS or IDS, bevacizumab must not be administered 
less than 28 days before or 28 days following major surgery, and the post-operative 
incision must be fully healed.  
During the Maintenance Treatment Period, participants in all 3 Arms may continue 
bevacizumab for up to 15 months (inclusive of bevacizumab administered during the 
Chemotherapy Treatment Period) [AVASTIN®, 2016].  
Details on the administration of bevacizumab can be found in the local package insert; 
local practice guidelines for administration of bevacizumab should be followed. 
6.5.2.2. 
Paclitaxel-Carboplatin (Cycles 1 to 6) 
Paclitaxel and carboplatin may be administered per local practice guidelines if those 
guidelines differ from the description below. If a participant experiences a 
hypersensitivity to carboplatin, then cisplatin may be used in place of carboplatin. 
Desensitization to carboplatin will not be allowed on study. If a participant experiences 
hypersensitivity or clinically significant neuropathy on paclitaxel treatment, docetaxel 
can be substituted per the Investigator’s discretion. 
For participants in all 3 Arms, paclitaxel will be administered at 175 mg/m2 via a 
180-minute IV infusion on Day 1 of Q21D cycle during the Chemotherapy Run-In and 
Treatment Periods.  
For participants in all 3 Arms, paclitaxel will be followed by carboplatin administered at 
an AUC of 5 to 6 mg/mL/min via a 60-minute IV infusion on Day 1 of Q21D cycle 
during the Chemotherapy Treatment Period. 
Participants who have inoperable disease or who have undergone PDS will receive 
6 cycles of paclitaxel-carboplatin. 
Those participants who are to undergo IDS will receive 3 to 4 additional cycles of 
paclitaxel-carboplatin prior to surgery and an additional 2 to 3 cycles of 
paclitaxel-carboplatin in combination with dostarlimab/placebo following surgery, for a 
maximum of 6 cycles of chemotherapy that cannot be extended. Interval debulking 
surgery planned after 6 cycles of chemotherapy should be discussed with the Sponsor. 
6.6. 
Study Drug Accountability 
The Investigator or designee is responsible for maintaining accurate dispensing records of 
the study treatments throughout the clinical study. 
Details of maintaining drug accountability, including information on the accountability 
log, will be provided in the Pharmacy Manual. 
All dispensation and accountability records for dostarlimab/placebo will be available for 
review by the Unblinded Study Monitor, who will assume the responsibility to reconcile 
the dostarlimab/placebo study treatment accountability log. The Unblinded Pharmacist 
will dispense study dostarlimab/placebo treatment for each participant according to the 

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protocol and Pharmacy Manual. The Study Monitor (blinded or unblinded) will assume 
the responsibility to reconcile the niraparib study treatment accountability log. The 
pharmacist (blinded or unblinded) will dispense niraparib study treatment for each 
participant according to the protocol and Pharmacy Manual. 
6.7. 
Study Drug Handling and Disposal 
At the end of study, when all participants have stopped protocol treatment, complete drug 
reconciliation per batch should be available at the site for verification in order to allow 
drug destruction or return procedure. After receiving Sponsor approval in writing, the 
investigational site is responsible for destruction of study drug according to local 
regulations. If a site does not have the capability for onsite destruction, the Sponsor will 
provide a return for destruction service through a third party. Both the unused and 
expired study treatment must be destroyed, upon authorization of the Sponsor, according 
to local regulations and procedures, and a copy of the destruction form must be filed in 
the study binder. 
The medication provided for this study is to be used only as indicated in this protocol and 
only for the participants entered in this study. 

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7. 
ASSESSMENT OF EFFICACY 
7.1. 
Primary Efficacy Endpoint 
The primary efficacy endpoint is PFS, 
 
 
  
 
 The same imaging modality (CT or 
MRI) should be used throughout the study. Positron emission tomography/CT may be 
used according to clinical guidelines, but its use is not a study requirement.  
 
 
 
The central review process will be as follows: 
1. All imaging and supportive clinical data will be submitted for central review, as 
specified in the Imaging Charter. 
2. Blinded Independent Central Review (BICR) 
 will be 
conducted by 2 independent radiologists (along with an arbiter, as necessary). 
A central blinded clinician will review clinical information. 
Cycle timing will be delayed for treatment interruptions. Tumor assessment should occur 
according to Study Day schedule regardless of whether study treatment is interrupted 
(i.e., counting from C1D1 of the Chemotherapy or Maintenance Treatment Period as 
appropriate). If a participant discontinues treatment for a reason other than progression by 
RECIST v1.1, death, withdrawal of consent, or loss to follow-up, scans must continue at 
the specified intervals 
 Following completion of 3 years of maintenance therapy, in the 
absence of progression, participants will be evaluated clinically with annual scans and 
additional unscheduled scans for suspicion of disease progression based on increases in 
CA 125 or other suspicious symptoms. Participants may be considered for treatment 
beyond 3 years in consultation with the Sponsor.  
7.2. 
Secondary Efficacy Endpoints 
7.2.1. 
Overall Survival 
OS is defined as the date of randomization to the date of death by any cause. Following 
the EOT visit, survival status will be collected for all participants using acceptable 
means, including telephone contact. New malignancy information will also be collected 
as part of the telephone contact survival status assessment. 
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GSK may request that updated survival data be collected on randomized participants 
outside the protocol window noted in the Schedule of Events (Table 17). At the time of 
the request, the site will determine survival status for each participant by the method 
agreed with the participant (unless the participant has withdrawn consent for survival 
follow-up) or allowed per local regulations (i.e., public sources). 
Following the local implementation of Amendment 10, the study will conclude all post-
treatment, long-term follow-up data collection beyond 90 days (±14 days) after the last 
dose of study treatment (or for a minimum of 30 days post-treatment discontinuation if 
the participant starts alternative anticancer therapy, or no follow-up data collection is 
required for the study if the participant transitions to continue the treatment outside of the 
study). A participant’s most recent long-term follow-up visit, which is greater than or 
equal to 90 days (±14 days) post-treatment (if applicable), before Amendment 10 
becomes effective, will be recognized as the participant’s final follow-up visit.  
Updated survival data is no longer required following study discontinuation. 
7.2.2. 
BICR determined PFS per RECIST v1.1 
The BICR determined PFS
 
7.2.3. 
Health-Related Quality of Life 
Please see Section 3.6.2 for details on HRQoL. 
The HRQoL assessments should be conducted in clinic, on the day of study drug 
administration, prior to dosing or clinical procedures during the Chemotherapy Treatment 
and Maintenance Periods. They may be completed remotely if the participant is no longer 
actively returning to the site. It is estimated that HRQoL assessments will take less than 
20 minutes at each time point. Since these are questionnaires, their completion will not 
interfere with or prevent future treatment or clinical studies. HRQoL assessments should 
be administered prior to conducting any other procedures at each assessment.  
European Quality of Life 5-Dimension 5-Level Scale 
The EQ-5D-5L (Appendix 8) questionnaire is one of the most widely used instruments to 
measure HRQoL across oncology and non-oncology indications. It consists of a 
descriptive system and the European Quality (EQ) Visual Analogue Scale. The 
descriptive system comprises 5 questions, 1 for each of 5 domains: mobility, self-care, 
usual activities, pain/discomfort, and anxiety/depression. Each is rated according to 5 
response levels (“no problems,” “slight problems,” “moderate problems,” “severe 
problems,” “unable”/“extreme problems”). Responses to the questionnaire can be 
converted to a single utility index value. The EQ Visual Analogue Scale records the 
respondent’s self-rated health on a 100-point scale between “Best imaginable health 
state” and “Worst imaginable health state.” The absolute scores and change from baseline 
in the EQ-5D-5L VAS will be evaluated. 
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EORTC-QLQ-C30 and EORTC-QLQ-OV28 
The EORTC-QLQ-C30 (Appendix 9) is a 30-item questionnaire used to measure HRQoL 
in participants with cancer; it has been translated and validated in over 100 languages and 
has been used in more than 3,000 studies worldwide 
(https://qol.eortc.org/questionnaires/core/eortc-qlq-c30/). The EORTC-QLQ-C30 is 
composed of both multi-item scales and single-item measures. These include 5 functional 
scales (Physical functioning, Role functioning, Emotional functioning, Cognitive 
functioning, and Social functioning), 3 symptom scales (Fatigue, Nausea and vomiting, 
and Pain), 6 single items (Dyspnea, Insomnia, Appetite loss, Constipation, Diarrhea, and 
Financial difficulties) and a global health status/health-related quality of life scale. The 
EORTC-QLQ-C30 employs a week recall period for all items and a 4-point scale for the 
functional and symptom scales/items with response categories “Not at all,” “A little,” 
“Quite a bit,” and “Very much.” The 2 items assessing global health status/quality of life 
utilize a 7-point scale ranging from 1 (“Very Poor”) to 7 (“Excellent”) [Aaronson, 1993].  
The EORTC-QLQ-C30 is often used with other disease-specific instruments such as the 
ovarian-specific EORTC-QLQ-OV28 (Appendix 10), which assesses ovarian cancer 
participants’ abdominal/gastrointestinal symptoms, other chemotherapy side effects, 
hormonal/menopausal symptoms, body image, attitude to disease/treatment, and sexual 
functioning.  
The absolute scores and change from baseline in the EORTC-QLQ-C30, and 
EORTC-QLQ-OV28 HRQoL assessments will be evaluated. 
7.2.4. 
Time to First Subsequent Therapy 
TFST is defined as the time from the date of randomization to the start date of the first 
subsequent anticancer therapy or death of any cause, whichever occurs first. 
7.2.5. 
Time to Second Subsequent Therapy 
TSST is defined as the time from the date of randomization to the start date of the second 
subsequent anticancer therapy or death of any cause, whichever occurs first. 
7.2.6. 
Progression-Free Survival 2 
PFS2 is defined as the time from the date of randomization to the date of first PD per 
Investigator’s assessment after initiation of subsequent anticancer therapy or death due to 
any cause, whichever occurs first. 
7.2.7. 
Objective Response Rate 
ORR is defined as the proportion of participants with CR or PR 
 
 (Appendix 4), for participants with measurable disease at 
baseline.  
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7.2.8. 
Duration of Response 
DOR is defined as the time from first documentation of CR or PR 
 
 (Appendix 4) 
or death by any cause, whichever occurs first for participants with measurable disease at 
baseline.  
7.2.9. 
Disease Control Rate 
DCR is defined as the proportion of participants with a best overall response of CR, PR, 
or SD 
 (Appendix 4), for participants with 
measurable disease at baseline.  
7.3. 
Biomarker Endpoints 
7.4. 
Immunogenicity Endpoints 
7.5. 
Pharmacokinetic Endpoints 
Blood samples for the PK measurement of dostarlimab (Table 19) and niraparib (Table 
20) will be obtained for all participants at all sites. 
 
 
  
Complete instructions for collection, processing, shipping, and handling of biomarker and 
PK/
 samples are detailed in the study-specific Laboratory Manual. 
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8. 
ASSESSMENT OF SAFETY 
8.1. 
Safety Parameters 
8.1.1. 
Demographic/Medical History 
 
 
 
8.1.1.1. 
Disease History 
For disease history, the following will be documented: 
• Date of diagnosis 
• Tumor type 
• Stage at time of initial diagnosis 
• Histology and grade of disease at diagnosis 
• Genotyping, 
 
8.1.1.2. 
Medical and Surgical History 
Major medical and surgical history (including medication history and history of 
thrombocytopenia, neutropenia, leukopenia, or anemia) will be collected. Details of any 
prior invasive malignancy will be collected. Medical and surgical history will be obtained 
by interviewing the participant or by reviewing the participant’s medical records. 
8.1.1.3. 
Previous and Concomitant Medications 
Previous and concomitant medications will be documented as described in Section 5.2. 
Medications will be coded using World Health Organization (WHO) Anatomical 
Therapeutic Chemical classification. 
8.1.2. 
Vital Signs 
Blood pressure, temperature and heart rate (pulse) will be measured at Screening and at 
every visit. Additionally, BP and heart rate will be performed weekly for the first 8 weeks 
from the first dose of niraparib in the Maintenance Treatment Period (Table 17). 
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8.1.3. 
Weight and Height 
Weight and height will be measured in accordance with the schedule of events 
(Table 17). 
Height will be measured at Screening only. Weight will be measured at Screening and at 
every visit. 
8.1.4. 
Physical Examination 
Physical examinations and symptom-directed physical examinations will be performed in 
accordance with the schedule of events (Table 17). 
Any physical examination or vital sign abnormalities assessed as clinically significant 
should be recorded as an AE or SAE. If SAE criteria are met, the finding should be 
recorded and reported according to the SAE reporting process (see Section 8.2.5). 
8.1.5. 
Laboratory Assessments 
The following laboratory variables will be determined in accordance with the schedule of 
events (Table 17). 
These tests will be performed by the local laboratory at the clinical site. All labs in the 
Chemotherapy Treatment Period and the Maintenance Period may be performed up to -3 
days from Day 1 dosing. 
Any abnormal laboratory value assessed as clinically significant should be recorded as an 
AE. If SAE criteria are met or if the laboratory abnormality is an AESI (see 
Section 8.2.7), the event should be recorded and reported according to the SAE reporting 
process (see Section 8.2.5). 
Hematologic, blood chemistry and coagulation factor testing may occur more frequently 
than is specified in the Schedule of Events in Table 18, if medically indicated per 
Investigator judgment or if the event meets the criteria for study treatment dose 
modification (see Section 3.4). Additional tests may be performed at a laboratory facility 
other than the study site, but the test results must be reported to the study site, the study 
site must keep a copy of test results with the participant’s study file, and the results must 
be entered into the eCRF. 
Any suspected case of MDS/AML or secondary cancer (new malignancy other than 
MDS/AML) reported while a participant is receiving treatment or followed for post-
treatment assessments must be referred for evaluation to a local hematologist to perform 
bone marrow aspirate and biopsy as per local practice. The study site must receive a copy 
of the hematologist’s report of aspirate/biopsy findings, which must include a 
classification according to WHO, and other sample testing reports related to MDS/AML. 
Report data will be entered in the appropriate eCRF pages, and the site must keep a copy 
of all reports with the participant’s study file. 

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8.1.5.1. 
Hematology 
The following hematologic parameters will be measured: 
• CBC: 
− Hemoglobin 
− Platelet count 
− White blood cell count 
− Differential white blood cell count 
• Coagulation factors: 
− International normalized ratio 
− Activated partial thromboplastin time 
8.1.5.2. 
Blood Chemistry 
The following blood chemistry parameters will be measured: 
• Blood chemistry: 
− Sodium 
− Potassium 
− Chloride 
− Calcium 
− Magnesium 
− Glucose  
− Total bilirubin 
− AST 
− ALT 
− Total protein 
− Albumin 
− Creatinine 
− Urea or blood urea nitrogen 
− Thyroid function (thyroid stimulating hormone [TSH]) 
− Amylase 

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8.1.5.3. 
Tumor Marker 
CA 125 will be obtained at Screening and at Day 1 of each cycle during the 
Chemotherapy Treatment Period and at Day 1 of each cycle during the Maintenance 
Treatment Period. After 1 year of maintenance (i.e., after cycle 17), CA 125 will be 
obtained Q6W until end of treatment. 
8.1.5.4. 
Urine Protein 
For participants receiving bevacizumab, urine dipstick for protein determination will be 
performed at Screening. Participants discovered to have ≥2 proteinuria on dipstick should 
not be administered bevacizumab, should undergo a 24-hour urine collection, and must 
demonstrate <2 g of protein in 24 hours to be eligible for bevacizumab treatment. 
8.1.5.5. 
Drug Screen 
Not applicable. 
8.1.5.6. 
Pregnancy Screen 
Niraparib and dostarlimab are known to have properties that require the participant to use 
contraception and may have adverse effects on a fetus in utero. A negative serum or urine 
pregnancy test is required within 3 days prior to C1D1 for females of childbearing 
potential. Urine pregnancy testing will be performed on Day 1 of each subsequent cycle 
and at the Safety Follow-Up Visit. Participants should start using birth control from 
Screening throughout the study period up to 180 days after the last dose of study 
treatment. If there is any question that a participant will not reliably comply with the 
contraception requirements, they should not be enrolled in the study, and any participant 
who becomes pregnant should be withdrawn from the study. Any pregnancies that occur 
within 180 days post-treatment discontinuation are to be reported as described in 
Section 8.2.11. 
8.1.6. 
Hepatitis B and Hepatitis C Testing 
Hepatitis B virus/Hepatitis C virus (HBV/HCV) testing will be done at Screening. 
8.1.7. 
ECOG Performance Status 
Performance status will be assessed using the ECOG scale (see Appendix 6) in 
accordance with the schedule of events (Table 17). The same observer should assess 
performance status each time. 
8.1.8. 
Electrocardiogram 
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8.2. 
Adverse and Serious Adverse Events 
8.2.1. 
Definitions 
8.2.1.1. 
Adverse Event 
Any untoward medical occurrence that occurs in a participant 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 unfavorable and 
unintended sign (including clinically significant laboratory findings), symptom, or 
disease temporally associated with the use of an investigational product or other study 
treatment, whether or not considered related to the product. 
Adverse events may include the onset of new illness and the exacerbation of pre-existing 
medical conditions. An AE can include an undesirable medical condition occurring at any 
time after the signing of the informed consent, including baseline or washout periods, 
even if no study treatment has been administered (See Section 8.2.3 for information about 
AE collecting and reporting.). 
8.2.1.2. 
Serious Adverse Event 
Any untoward medical occurrence, that, at any dose: 
• Results in death; 
• Is life threatening (i.e., an event in which the participant 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 it were more severe); 
• Requires inpatient hospitalization⃰ or prolongation of existing hospitalization;  
• Results in persistent or significant disability or incapacity; 
• Is a congenital abnormality or birth defect;  
• Is an important medical event† 
⃰Exception: Hospitalization for elective procedures, for protocol compliance, or for 
observation will not be considered criteria for an SAE. Adverse events due to disease 
progression do not need to be reported as SAEs because they are part of the natural 
history of advanced cancer. The reason for the planned hospitalization should be captured 
in medical history section in the eCRF. Complications experienced during these 
hospitalizations must be reported as AEs (or SAEs, if hospitalization is prolonged due to 
the AE).  
†Medical and scientific judgment should be exercised in determining whether situations 
or events should be considered SAEs: an important medical event may not be 
immediately life-threatening or result in death or require hospitalization but may 
jeopardize the participant or require intervention to prevent one of the above outcomes. 
Examples of such events are allergic bronchospasm, blood dyscrasias, or convulsions that 
may require intensive treatment in an emergency room or at home but do not result in 
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disease associated with the administration of the study drug. (See Section 8.2.5 for 
information about SAE reporting.) 
8.2.1.3. 
Treatment-Emergent Adverse Event  
Any event that was not present prior to the initiation of study treatment or any event 
already present that worsens in either intensity or frequency following exposure to study 
treatment.  
8.2.1.4. 
Adverse Event of Special Interest  
Any AE (serious or non-serious) that is of scientific and medical concern specific to the 
study treatment, for which ongoing monitoring and rapid communication by the 
Investigator to the Sponsor is appropriate. 
8.2.1.5. 
Overdose 
An overdose is a deliberate or accidental administration of study treatment to a study 
participant, at a dose greater than that which was assigned to that participant per the study 
protocol and under the direction of the Investigator. If an overdose occurs, the 
Investigator and the Sponsor should be notified immediately, and the participant should 
be observed closely for AEs. Associated AEs should be treated and monitored by the 
Investigator. The dosage of study drug administered, any associated AEs, and/or 
treatment provided to the participant because of the overdose, should be documented on 
the applicable sections within the eCRF.  
8.2.2. 
Assessment of Adverse Events  
8.2.2.1. 
Severity Assessment  
All AEs will be assessed by the Investigator for severity according to Common 
Terminology Criteria for Adverse Events (CTCAE) v4.03: 14 June 2010; NIH, National 
Cancer Institute (NCI). The CTCAE severity grades 1 through 5 provide unique clinical 
descriptions of severity of each AE. The CTCAE v4.03 is available on the NCI/NIH 
website. 
Please note that there is a distinction between serious and severe AEs: Severity is a 
measure of intensity whereas seriousness is defined by the criteria in Section 8.2.1.2. For 
example, a mild degree of gastrointestinal bleeding requiring an overnight hospitalization 
for monitoring purposes may be considered an SAE but is not necessarily severe. 
8.2.2.2. 
Relationship to Study Intervention 
The Investigator must provide a causality assessment regarding the relationship of the 
event with the study drug and/or study procedure for all AEs. One of the following 
categories should be selected based on medical judgment, considering all contributing 
factors: 
• Related: A causal relationship between the medicinal product (or study 
procedures or both) and AE is a reasonable possibility. For example, the 
occurrence of the AE cannot be explained by other causative factors. The AE, 

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however, can be explained by pharmacological effect of the medicinal product 
such as a similar event having been reported previously, alteration of the dose 
effect, or the timing or seriousness of the AE, etc. Positive 
rechallenge/dechallenge is supportive.  
• Not Related: A causal relationship between the medicinal product (or study 
procedures or both) and AE is not a reasonable possibility: there is no 
temporal relationship between the medicinal product and event, or an 
alternative etiology is more reasonable. 
8.2.2.3. 
Expectedness 
The Sponsor will be responsible for determining whether an AE is ‘expected’ or 
‘unexpected’. An AE will be considered unexpected if the nature, severity, or frequency 
of the event is not consistent with the risk information provided in the Reference Safety 
Information in the niraparib or dostarlimab IB. 
8.2.3. 
Collection and Recording Adverse Events 
Adverse events may be volunteered spontaneously by the study participant, or discovered 
by the study staff during physical examinations or by asking an open, non-leading 
question such as, “How have you been feeling since your last study visit?” The 
Investigator will document the nature of AE, date of onset of the AE (and time, if 
known), date of outcome of the AE (and time, if known), severity of the AE, action taken 
with study drug as a result of the AE, assessment of the seriousness of the AE, and 
assessment of the causal relationship of the AE to study drug and/or study procedure. 
Adverse events, including laboratory abnormalities that are assessed as clinically 
significant or require intervention, should be described using a diagnosis whenever 
possible, rather than individual underlying signs and symptoms. When a clear diagnosis 
cannot be identified, each sign or symptom should be recorded as a separate AE. 
All SAEs will be collected from the signing of the ICF for this study up to 90 days (±14 
days) after the last dose of study treatment (or for a minimum of 30 days post-treatment 
discontinuation if the participant starts alternative anticancer therapy) and recorded in the 
eCRF. Serious AEs will also be reported on an SAE form as described in Section 8.2.5 of 
this protocol.  Once the specified post-treatment safety reporting period has elapsed, if the 
Investigator learns of an SAE that is considered reasonably related to the study 
intervention or study participation, the Investigator must promptly notify the Sponsor. 
All AEs, regardless of the source of identification (e.g., physical examination, laboratory 
assessment, ECG, or reported by participant), will be collected and recorded in the eCRF 
for each participant from the signing of the ICF for this study up to 30 days after the last 
dose of study treatment. 
Concomitant illnesses that existed before entry into the study will not be considered AEs 
unless the illness worsens during the Treatment Period. Pre-existing conditions will be 
recorded as Medical History in the eCRF and on the SAE Report Form. 

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Disease progression is an efficacy criterion and is therefore not considered an AE or SAE 
(even if fatal). Disease progression should be reported within the eCRF. If AEs/SAEs 
occur in relation to disease progression that are not consistent with the natural 
progression of the participant’s disease, these AEs/SAEs must be reported per AE/SAE 
reporting requirements described in Section 8.2.5. 
8.2.3.1. 
Safety Reporting During PACT 
For participants in the PACT phase of the study, the Sponsor will continue to collect 
safety information. Investigators must report directly to the Sponsor all SAEs, AEs 
leading to study treatment discontinuation, overdose, AESIs, and pregnancy cases via 
paper forms. SAEs, AEs leading to study intervention discontinuation, AESI, and 
overdose cases will be reported during the PACT study intervention period and for up to 
90 days (±14 days) after the last dose of study treatment (or for a minimum of 30 days 
post-treatment discontinuation if the participant starts alternative anticancer therapy). 
Any pregnancies that occur within 180 days post-treatment discontinuation will be 
captured for all participants (not only participants in PACT Phase), in accordance with 
Section 8.2.11.    
For all PACT phase participants who transition to continue treatment outside of the study 
(for example through Managed Access route or commercial access), the day of their last 
dose of study intervention during the PACT phase is the end date for safety collection 
and reporting for this study. Once the specified post-treatment safety reporting period has 
elapsed, investigators are not obliged to actively seek information on AEs, SAEs or 
AESIs, however if the Investigator learns of an AESI or an SAE that is considered 
reasonably related to the study intervention or study participation, the Investigator must 
promptly notify the Sponsor. The Sponsor retains the right to request additional 
information for any participant with ongoing AEs/SAEs/AESIs at EOS, if judged 
necessary. 
Additionally, any SAEs that are ongoing at the time of the final DCO (prior to PACT) 
must be followed up to resolution unless the event is considered by the Investigator 
unlikely to resolve, or the participant is lost to follow-up. Updates to these events will 
also occur via paper forms directly to the Sponsor. The Sponsor retains the right to 
request additional information for any participant with ongoing AEs/SAEs/AESIs at final 
DCO, if judged necessary. 
8.2.4. 
Follow-Up of Adverse Events 
All AEs experienced by a participant, regardless of the suspected causality, will be 
monitored until the AE or SAE has resolved, until any abnormal laboratory values have 
returned to baseline or normal levels, until stabilized with a satisfactory explanation for 
the changes observed, until the participant is lost to follow-up, or until the participant has 
died. 
If an Investigator becomes aware of an SAE after the specified follow-up period and 
considers the SAE related to the study drug, the Investigator should report the SAE to the 
Sponsor according to timelines for reporting SAEs described in Section 8.2.3.  

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8.2.5. 
Reporting 
The Investigator must report all SAEs, and all follow-up information to the Sponsor on 
an SAE Report Form within 24 hours of becoming aware of the initial event or follow-up 
information. The Investigator must provide a causality assessment and must sign and date 
all SAE Report Forms.  
It is the responsibility of the Investigator to review source documentation and describe 
pertinent information on the SAE Report Form. If supporting documentation is requested 
(e.g., hospital reports, consultant reports, death certificates, autopsy reports, etc.), the 
Investigator should highlight all relevant and pertinent information within such 
documents, ensure that any participant's personal identifiers (including Medical Record 
number) are removed, and submit the documents with the SAE Form to the Sponsor. The 
Sponsor (or designee) will return a confirmation of receipt for all email reports (if 
received from other than a "no reply" domain) within 1 business day.  
After receipt of the initial report, the Sponsor (or designee) will review the information 
and, if necessary, contact the Investigator to obtain further information. The Investigator 
must promptly respond to queries from the Sponsor. 
The sponsor has a legal responsibility to notify both the local regulatory authority and 
other regulatory agencies about the safety of a study intervention under clinical 
investigation. The sponsor will comply with country-specific regulatory requirements 
relating to safety reporting (including Suspected Unexpected Serious Adverse Reaction 
[SUSAR reporting]) to the regulatory authority, institutional review boards 
(IRBs)/independent ethics committees (IECs), and investigators. 
In the PACT phase, all completed paper safety reports must be sent to the Sponsor by 
email or fax within the timeframes shown in Table 15. 

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Table 15: 
Timeframes for Submitting SAE, Pregnancy and Other Event 
Reports to GSK in the PACT Phase  
Type of event 
Initial reports 
Follow-up of relevant 
information on a previous 
report 
 
Timeframe 
Documents 
Timeframe 
Documents 
SAEs 
24 hours*‡ 
paper SAE 
report form 
24 hours* 
paper SAE 
report form 
Pregnancies 
24 hours* 
paper 
pregnancy 
notification 
form 
24 hours* 
paper 
pregnancy 
follow-up form 
AESIs  
24 hours**‡ 
paper AE or 
SAE (as 
applicable) 
report form 
24 hours* 
paper AE or 
SAE (as 
applicable) 
report form  
Overdose 
24 hours* 
paper AE or 
SAE (as 
applicable) 
report form 
24 hours* 
paper AE or 
SAE (as 
applicable) 
report form 
AE leading to 
discontinuatio
n 
24 hours* 
paper AE or 
SAE (as 
applicable) 
report form 
24 hours* 
paper AE or 
SAE (as 
applicable) 
report form 
AE = Adverse event; AESIs = Adverse event of special interest; SAE = Serious adverse event. 
* Timeframe allowed after receipt or awareness of the information by the investigator/site staff. 
** Timeframe allowed once the investigator determines that the event meets the protocol definition of an 
AESI. 
‡ Paper Reports will be dated and signed by the investigator (or designee). For each SAE/AESI, the 
investigator(s) must document in the medical notes that they have reviewed the SAE/AESI and have 
provided an assessment of causality. 
 
8.2.6. 
Submission and Distribution of Serious Adverse Event Reports 
Per regulatory requirements, if an event is assessed by the Sponsor as a SUSAR, it is the 
responsibility of the Sponsor to submit the SUSAR to Regulatory Authorities according 
to applicable regulations and in accordance with regional reporting requirements. For 
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reactions (SARs) and report SUSARs in an expedited manner to the EudraVigilance 
database in accordance with CTR 536/2014 Annex I D20(c). Sponsor policy and 
applicable provision to Investigators as necessary should also apply. 
In addition, the SUSAR will be distributed to the Investigators/sites, utilizing a Council 
for International Organizations of Medical Sciences report form, or the MedWatch 
3500A form. Urgent safety measures and/or other events that are not SUSARs that are 
determined to potentially affect the benefit-risk balance of the clinical trial will also be 
submitted by the Sponsor to Regulatory Authorities according to applicable local 
regulations. 
The timelines for reporting SUSARs by the sponsor are:  
• In the case of fatal or life-threatening SUSARs, within 7 calendar days after the 
sponsor became aware of the reaction; 
• In the case of non-fatal or non-life-threatening SUSARs, within 15 calendar days 
after the sponsor became aware of the reaction; 
• In the case of a SUSAR which was initially considered to be non-fatal or non-life 
threatening, but which turns out to be fatal or life-threatening, within 7 calendar 
days after the sponsor became aware of the reaction being fatal or life-threatening. 
8.2.7. 
Adverse Events of Special Interest 
AESIs for niraparib are the following:  
• MDS and AML 
• Secondary cancers (new malignancies other than MDS or AML) 
There are no AESIs for dostarlimab.  
Reporting AESIs: All occurrences of AESIs must be reported. If the AESI is serious, it 
should be reported in EDC; if the AESI is nonserious, it should be reported on a 
designated AESI paper form. The completed electronic SAE custom report from EDC or 
the AESI paper form must be sent to the Sponsor by email or fax within 24 hours of 
awareness of the event.  
AESI should be collected and reported as follows: 
• MDS and AML and secondary cancers (new malignancies other than 
MDS/AML) should be reported to the Sponsor until death or loss to follow-
up.  
• During the PACT phase, investigators must continue to directly report AESIs 
during treatment with niraparib and for 90 days after the last dose of niraparib. 
If the Investigator learns of an AESI after the last dose of niraparib, the 
Investigator must promptly notify the Sponsor. 

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8.2.8. 
Myelodysplastic Syndrome/Acute Myeloid Leukemia 
MDS and AML including cases with fatal outcome, have been reported with the use of 
niraparib. In clinical trials, the duration of niraparib treatment in participants prior to 
developing MDS/AML varied from 1 month to >4 years. The cases were typical of 
secondary, cancer therapy-related MDS/AML. All participants had received 
platinum-containing chemotherapy regimens, and many had also received other DNA-
damaging agents and radiotherapy. Some of the participants had a history of bone 
marrow suppression. For suspected MDS/AML or prolonged hematological toxicities, the 
participant should be referred to a hematologist for further evaluation. If MDS and/or 
AML is confirmed, then niraparib should be permanently discontinued and the participant 
should be treated appropriately. 
8.2.9. 
Hypertension, Including Hypertensive Crisis 
Hypertension, including hypertensive crisis, has been reported with the use of niraparib. 
Pre-existing hypertension should be adequately controlled before starting niraparib 
treatment. While receiving treatment, hypertension should be medically managed with 
antihypertensive medicinal products with or without niraparib dose adjustment.  
Blood pressure and heart rate should be monitored at least weekly for the first 2 months 
of niraparib treatment in the maintenance setting, then monthly for the first year and 
periodically thereafter during treatment with niraparib. Niraparib should be discontinued 
in case of hypertensive crisis or if medically significant hypertension cannot be 
adequately controlled with antihypertensive therapy. 
8.2.10. 
Posterior Reversible Encephalopathy Syndrome 
There have been rare reports of niraparib-treated patients developing signs and symptoms 
that are consistent with posterior reversible encephalopathy syndrome (PRES). PRES is a 
rare neurologic disorder that can present with the following signs and symptoms 
including seizures, headache, altered mental status, visual disturbance, or cortical 
blindness, with or without associated hypertension. A diagnosis of PRES requires 
confirmation by brain imaging, preferably magnetic resonance imaging. In patients 
developing PRES, treatment of specific symptoms including control of hypertension is 
recommended, along with discontinuation of niraparib. The safety of reinitiating 
niraparib therapy in patients previously experiencing PRES is not known. 
8.2.11. 
Pregnancy 
The Investigator must report all pregnancies and the outcomes to the Sponsor. The 
Sponsor has the responsibility to monitor the outcome of all pregnancies reported during 
the clinical study. 
Each pregnancy must be reported by the Investigator to the Sponsor on an Initial 
Pregnancy Report Form within 24 hours of becoming aware of the pregnancy. Pregnancy 
is not an AE, and therefore does not need to be reported as an AE in the eCRF unless 
there is a suspicion that the study drug may have interfered with the effectiveness of a 
contraceptive medication. The Investigator must follow-up all pregnancies, document the 
course and the outcome, and report this information to the Sponsor on a Pregnancy 

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Outcome Report Form within 24 hours of becoming aware - even if the participant was 
withdrawn from the study or the study has finished. 
An elective abortion without complications should not be regarded as an AE, however, it 
should be reported as the outcome to the pregnancy on the Pregnancy Outcome Report 
Form. Therapeutic abortions should be reported as a treatment procedure; the reason for 
the therapeutic abortion should be reported on the Pregnancy Outcome Report Form and 
as an AE in the eCRF. Hospitalization for normal delivery of a healthy newborn should 
not be considered an SAE. 
Any SAE that occurs during pregnancy must be recorded on the Pregnancy Outcome 
Report Form, reported as an SAE on the SAE Report Form (e.g., maternal serious 
complications, therapeutic abortion, ectopic pregnancy, stillbirth, neonatal death, 
congenital anomaly, birth defect) and reported to the Sponsor within 24 hours. 
Hospitalization for normal delivery of a healthy newborn should not be considered an 
SAE.  
After the study transitions to the PACT phase, investigators must continue to directly 
report pregnancies for up to 180 days following the last dose of study treatment for all 
participants. This includes those who discontinued study treatment prior to the PACT 
phase, as well as participants continuing in the PACT phase.  

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9. 
STATISTICS 
Full details of the statistical analyses will be provided in the study’s statistical analysis 
plan (SAP). The SAP will be finalized prior to database lock. Any changes to the 
methods described in the plan will be described and justified in the final clinical study 
report. 
All analyses will include summary statistics, including the number and percentage for 
categorical variables and the number of participants, mean, standard deviation, median, 
minimum, and maximum for continuous variables. Time-to-event analyses will be 
performed using the Kaplan Meier method. Two-sided 95% CIs will be provided where 
appropriate. 
9.1. 
Sample Size Determination 
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9.2. 
Analysis Populations 
• 
The ITT population consists of all randomized participants. Any deceased 
participants randomized in error with death prior to randomization will be excluded 
from the population. Participants will be analyzed as randomized.  
• 
The Safety Analysis Population includes all randomized participants who received 
at least 1 dose of study treatment after randomization. Participants will be analyzed 
according to the treatment that they actually received. 
• 
The PK Analysis Population is defined as all participants in Arm 2 (niraparib only) 
and Arm 3 (both niraparib and dostarlimab) who received at least 1 dose of either 
drug and have at least 1 measurable postdose PK result. PK populations are defined 
separately for niraparib and dostarlimab. 
9.3. 
Demographics, Medical History, Baseline Characteristics, and 
Concomitant Medications 
9.4. 
Efficacy Analyses 
 
 
9.4.1. 
Primary Efficacy Analysis 
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9.4.2. 
Secondary Efficacy Analyses 
9.5. 
Safety Analyses 
9.6. 
Interim Analyses 
Planned periodic safety analyses will be conducted by the IDMC after 24 randomized 
 
  
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9.7. 
Final Analyses 
A final safety analysis at the time of final DCO will be performed. 
9.8. 
Biomarker Analysis 
 
 
9.9. 
Immunogenicity Analysis 
 
 
 
 
9.10. 
Pharmacokinetic Analysis 
9.10.1. 
Statistical Analysis of PK Data 
 
  
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9.10.2. 
Exploratory Biomarker Analyses 
If deemed appropriate and if data permit, 
 
 
 
 
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10. 
DIRECT ACCESS TO SOURCE DATA/DOCUMENTS 
10.1. 
Study Monitoring 
Before an investigational site can enter a participant into the study, a representative of the 
Sponsor will visit the investigational study site to: 
• Determine the adequacy of the facilities to support the clinical trial, including, 
but not limited to, clinical sample collection and management as per the 
laboratory manual. 
• Discuss with the Investigator(s) and other personnel their responsibilities with 
regard to protocol adherence, and the responsibilities of the Sponsor or its 
representatives. This will be documented in a Clinical Study Agreement 
between the Sponsor and the Investigator. 
During the study, a monitor from the Sponsor or representative will have regular contacts 
with the investigational site, for the following: 
• Provide information and support to the Investigator(s). 
• Confirm that facilities remain acceptable and that clinical samples are being 
appropriately managed. 
• Confirm that the investigational team is adhering to the protocol, that data are 
being accurately recorded in the case report forms, and that investigational 
product and other study treatment accountability checks are being performed. 
• Perform source data verification. This includes a comparison of the data in the 
case report forms with the participant’s medical records at the hospital or 
practice, and other records relevant to the study. This will require direct access 
to all original records for each participant (e.g., clinic charts). 
• Record and report any protocol deviations not previously sent to the Sponsor. 
• Confirm AEs and SAEs have been properly documented on eCRFs, and 
confirm any SAEs have been forwarded to the Sponsor and those SAEs that 
met criteria for reporting have been forwarded to the IRB. 
The monitor will be available between visits if the Investigator(s) or other staff needs 
information or advice. 
10.2. 
Audits and Inspections 
Authorized representatives of the Sponsor, a regulatory authority, an IEC, or an IRB may 
visit the site to perform audits or inspections, including source data verification. The 
purpose of a Sponsor audit or inspection is to systematically and independently examine 
all study-related activities and documents to determine whether these activities were 
conducted, and data were recorded, analyzed, and accurately reported according to the 
protocol, Good Clinical Practice (GCP) guidelines of the ICH, and any applicable 
regulatory requirements. The Investigator should contact the Sponsor immediately if 
contacted by a regulatory agency about an inspection. 

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10.3. 
Institutional Review Board (IRB)/Institutional Ethics 
Committee (IEC) 
The Principal Investigator must obtain IRB or IEC approval, as appropriate, for the 
investigation. Initial IRB/IEC approval, and all materials approved by the IRB/IEC for 
this study including the participant consent form and recruitment materials must be 
maintained by the Investigator and made available for inspection. 

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11. 
QUALITY CONTROL AND QUALITY ASSURANCE 
To ensure compliance with GCPs and all applicable regulatory requirements, the Sponsor 
may conduct a quality assurance audit. The Sponsor will be responsible for notifying 
Regulatory Authorities of serious breaches of GCP per applicable local regulations. 
Please see Section 10.2 for more details regarding the audit process. 

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12. 
ETHICS 
12.1. 
Ethics Review 
The final study protocol, including the final version of the ICF, must be approved or 
given a favorable opinion in writing by an IRB or IEC, as appropriate. The Investigator 
must submit written approval to the Sponsor before he or she can enroll any participant 
into the study. 
The Principal Investigator is responsible for informing the IRB or IEC of any amendment 
to the protocol in accordance with local requirements. In addition, the IRB or IEC must 
approve all advertising used to recruit participants for the study. The protocol must be re-
approved by the IRB or IEC upon receipt of amendments and annually, as local 
regulations require. 
The Principal Investigator is also responsible for providing the IRB with reports of any 
reportable serious adverse drug reactions (ADR) from any other study conducted with the 
investigational product. The Sponsor will provide this information to the Principal 
Investigator. 
Progress reports and notifications of serious ADR will be provided to the IRB or IEC 
according to local regulations and guidelines. 
12.2. 
Ethical Conduct of the Study 
The study will be performed in accordance with ethical principles that have their origin in 
the Declaration of Helsinki (please see Appendix 7) and are consistent with ICH/GCP 
guidelines, applicable regulatory requirements, and the Sponsor’s policy on Bioethics. 
12.3. 
Written Informed Consent 
The Principal Investigator(s) at each center will ensure that the participant is given full 
and adequate oral and written information about the nature, purpose, possible risk, and 
benefit of the study. Participants must also be notified that they are free to discontinue 
from the study at any time. The participant should be given the opportunity to ask 
questions and allowed time to consider the information provided. 
The participant’s signed and dated informed consent must be obtained before conducting 
any study procedures. 
The Principal Investigator(s) must maintain the original, signed ICF. A copy of the 
signed ICF must be given to the participant. 

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13. 
DATA HANDLING AND RECORDKEEPING 
13.1. 
Inspection of Records 
The Sponsor will be allowed to conduct site visits to the investigation facilities for the 
purpose of monitoring any aspect of the study. The Investigator agrees to allow the 
monitor to inspect the drug storage area, study drug stocks, drug accountability records, 
participant charts and study source documents, and other records relative to study 
conduct. 
13.2. 
Retention of Records 
The Sponsor and the Investigator will ensure the clinical trial master file is archived for at 
least 25 years after the end of the clinical trial. Medical files of participants will be 
archived in accordance with national law.  
The clinical trial master file will be archived in a manner that guarantees its easy 
availability and accessibility for competent authorities upon their request. Any change in 
ownership of the clinical trial master file will be properly documented. The new owner 
will be required to uphold the responsibilities outlined in this protocol. As the sponsor, 
TESARO (GSK) will designate specific individuals within the organization to manage 
the archives. Access to these archives will be limited to these designated individuals. The 
media chosen for archiving the clinical trial master file will ensure the content remains 
intact and readable throughout the specified archiving period. 
The Principal Investigator must maintain all documentation relating to the study for a 
period of 2 years after the last marketing application approval or, if not approved, 2 years 
following the discontinuance of the test article for investigation. If it becomes necessary 
for the Sponsor or the Regulatory Authority to review any documentation relating to the 
study, the Investigator must permit access to such records. 
14. 
PUBLICATION POLICY 
GSK seeks to publish medically or scientifically significant results in searchable peer-
reviewed scientific literature within 18 months from Last Subject Last Visit (LSLV). The 
publication policy is based on the guidelines described in the Joint ENGOT and GOG-
Foundation Requirements for Trials with Industry Partners [Vergote, 2019] and agreed 
upon by the FIRST Publication Steering Committee Charter which outlines the 
conditions for authorship, decision-making, data analysis, and publication guidelines. 
Information regarding publication of study results is contained in the Clinical Trial 
Agreement for this study. GSK follows the International Committee of Medical Journal 
Editors standards for authorship and implements the Good Publication Practices to guide 
its publications.  

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16. 
APPENDICES 
APPENDIX 1. SCHEDULE OF EVENTS 
Post Analysis Continuation of Treatment (PACT)_ Phase: 
Following the DCO date for final analysis, the study may move into the PACT phase (see Section 5.6 for details). Participants who 
continue to receive study intervention during the PACT phase will be monitored and will receive follow-up care in accordance with 
standard local clinical practice. Assessments will revert to the standard of care at a participant’s particular study site and only SAEs, AEs 
leading to discontinuation of study intervention, overdoses, AESIs, and pregnancy cases will be reported directly to the sponsor via paper 
forms (Section 8.2.5).  
Prior to PACT Phase (All Ongoing Patients): 
Following the analysis conducted at the 31 October 2024, DCO date, no further efficacy analyses will be conducted for the study, as 
outlined in Section 9.6. Consequently, the scope of data collection is reduced, aligning with the revised schedule of events detailed in 
Table 16. 

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Table 16: 
Schedule of Events: Prior to PACT (All Ongoing Participants) 
Visit 
 
Procedurej 
Maintenance 
Treatment Perioda, b, i 
EOT 
Safety Follow-
Upk 
Post-Treatment 
Assessment c, h 
 
C(n) 
 
 
 
Day 
1 
Within 7 days 
of last dose 
30 (±7) days 
90 (±14) days 
(applicable to SAE 
and AESI 
reporting only) 
Physical examination 
 
X 
X 
 
Vital signs 
X 
X 
 
 
AE/SAE/AESI reportingc 
X 
X 
X 
X 
ECOG performance status 
X 
X 
 
 
CBC with differentiald 
X 
X 
X 
 
Blood chemistryf 
X 
X 
X 
 
TSHe 
Q6W 
 
 
 
Amylasee 
Q6W 
 
 
 
Pregnancy reportingc 
 
Any 
pregnancies 
that occur 
 
 

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Visit 
 
Procedurej 
Maintenance 
Treatment Perioda, b, i 
EOT 
Safety Follow-
Upk 
Post-Treatment 
Assessment c, h 
within 
180 days post-
treatment 
discontinuation 
are to be 
reported as 
described in 
Section 8.2.11.  
Oral niraparib dispensed or collected 
X 
 
 
 
IV dostarlimab infusionsg 
Q6W 
 
 
 
Concomitant medications 
X 
X 
X 
X 
Anticancer therapies assessment c, h, k 
 
 
X 
X 
RECIST v1.1 assessment Chest/Abdomen/Pelvis CT or MRIl 
X 
 
 
 
Bone marrow aspirate and biopsy 
For any suspected MDS/AML case reported while on 
study, a bone marrow aspirate/biopsy must be performed 
by a local hematologist to confirm MDS/AML. 
 
Abbreviations: AE=adverse event; AESI=AE of special interest; AML=acute myeloid leukemia; C=cycle 125; CBC=complete blood count; ECOG=Eastern 
Cooperative Oncology Group; EOT=end of treatment; IV=intravenous; MDS=myelodysplastic syndrome; Q6W=every 6 weeks; SAE=serious adverse event, 
TSH=thyroid stimulating hormone; wks=weeks. 
a All labs in the Maintenance Period may be performed up to -3 days from Day 1 dosing. 
b In the Maintenance Treatment Period: Prior to dosing of study drug, the PI must review a CBC, blood chemistry, TSH, and amylase assessment. 
c All AEs are required to be captured through 30 days after cessation of study treatment. SAEs are required to be captured through 90 days after the last dose of study 
treatment (or for a minimum of 30 days post-treatment discontinuation if the participant starts alternative anticancer therapy). Investigators must continue to directly 

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report AESIs during treatment with niraparib and for 90 days after the last dose of niraparib.  If the Investigator learns of an AESI after the last dose of niraparib, the 
Investigator must promptly notify the Sponsor. Any pregnancies that occur within 180 days post-treatment discontinuation will be captured for all participants (not 
only participants in PACT Phase). If applicable, when a patient transitions off study to continue treatment prior to PACT, safety reporting should be via the reporting 
mechanism applicable to the access route outside the study. Once the specified safety reporting period has elapsed, investigators are not obliged to actively seek 
information on AEs, SAEs or AESIs, however if the Investigator learns of an AESI or an SAE that is considered reasonably related to the study, it should be reported 
directly to GSK Global Safety through the standard specified reporting routes.  
d If dose interruption or modification is required at any point on study because of hematologic toxicity, weekly (±3 days) blood draws for CBC will be monitored 
until the AE resolves, and to ensure safety of the new dose, weekly (±3 days) blood draws for CBC will also be required for an additional 4 weeks after the AE has 
been resolved to the specified levels (week 1 - first dose after re-start [CXM day 1], week 2 – 7 days after re-start [CXM day 8], week 3 – 14 days after re-start [CXM 
day 15], week 4 – 21 days after re-start [CX+1M day 1], after which monitoring every 4 weeks may resume. After 1 year of maintenance (after cycle 17), CBC will 
be done every 6 weeks.  
e TSH and amylase will only be collected for patients on Arm 3 (for patients either actively receiving dostarlimab with Niraparib or dostarlimab alone or 
discontinued dostarlimab but continue to receive Niraparib on Arm 3). TSH and amylase will not be collected for patients receiving Niraparib alone (applicable to 
participants in Arm 2 or Arm 1 (previously unblinded according to amendment 4).   
f The following blood chemistry parameters will be measured: sodium, potassium, chloride, calcium, magnesium, glucose, total bilirubin, AST, ALT, total protein, 
albumin, creatinine, and urea or blood urea nitrogen. Blood chemistry will be done every 6 weeks. 
g In the Maintenance Treatment Period, IV dostarlimab will be administered every 42 days (6 weeks). On days that participants receive oral niraparib and or IV 
dostarlimab, dostarlimab will be administered first, and then niraparib (only applicable to participants on Arm 3).  
h  After the 30-day (±7 days) safety follow-up visit, participants will undergo one post-treatment follow-up assessment for serious adverse events (SAEs) and adverse 
events of special interest (AESIs) at 90 days after their last dose of study treatment. If a participant transitions to treatment outside of the study prior to PACT or if an 
Arm 1 participant (not previously unblinded discontinues placebo), post-treatment follow-up assessments will not be conducted. Following the local implementation 
of Amendment 10, the study will conclude all post-treatment follow-up data collection after 90 days (±14 days) from the last dose of study treatment, or after a 
minimum of 30 days if the participant begins alternative anticancer therapy. No follow-up data collection is required for participants who transitions to continue the 
treatment outside of the study. A participant’s latest long-term follow-up visit which greater or equal to 90 days (±14 days) post-treatment (if applicable), before 
Amendment 10 becomes effective, will be recognized as the participant’s final follow-up visit.  
i During the maintenance treatment period, participants may return for clinic visits and assessments every 6 weeks, to coincide with the dostarlimab IV administration. 
Participants will be dispensed 2 bottles of niraparib every 6 weeks to coincide with dostarlimab IV administration.  
j. All tests and procedures are required to be performed, and results evaluated prior to dosing 
k. Safety follow-up visit is only needed for participants who have not begun a follow-up anticancer therapy. Participants transitioning to treatment outside the study 
before PACT or Arm 1 participants discontinuing placebo study drugs, as per amendment 4, do not require this visit. 
l. RECIST v1.1 tumor assessment via CT or MRI scan of chest/abdomen/pelvis and clinically indicated areas during the Maintenance Treatment Period, is optional 
and participants may be evaluated clinically with annual scans until PD or up to maintenance therapy discontinuation, whichever is earliest. Additional unscheduled 
scans (of any anatomical region that may be clinically indicated) for suspicion of disease progression based on increases in CA 125 or other suspicious symptoms are 
allowed. Imaging modality must be consistent with previous assessments whenever feasible. Alternate imaging modalities are allowed for identification of new 
lesions in anatomical regions that have not been previously scanned. EOT scan will not be performed. Participants who discontinue study treatment in the absence of 

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PD per RECIST v1.1 are not to continue radiographic imaging.  If a participant discontinues treatment within 28 days of the scan that indicates PD, then the EOT 
scan will not be performed. 
 
Table 17: 
Schedule of Events: All Study Arms 
Visita 
 
Procedureb 
Pre-
Screeningc 
Screening 
Chem
o. 
Run-
In 
Period 
Chemo. 
Treatment 
Periodd 
Maintenance Treatment Periodd, e, aa 
EOT 
Safety 
Follow
-Up 
Post-
Treatment 
Assessmenty 
 
 
 
C1 
C2 
C(n) 
C1 
C2 
C(n) 
 
 
 
Day 
-42 to -29 
-28 to -1 
1 
1 
1 
1 
8 
15 
1 
8 
1 
Within 
7 days 
of last 
dose 
30 (±7) 
days 
after 
last 
dose 
Every 
90 (±14) days 
Pre-Screening 
Consent 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
Informed consent 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
Demographics 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
Medical, surgical, 
cancer (including 
genotyping), and 
medication history 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
Physical 
examination 
 
Xab 
 
 
 
 
 
 
 
 
 
X 
X 
 
Vital signs, height, 
and weightf 
 
Xab 
X 
X 
X 
X 
 
 
X 
X 
X 
X 
 
 
12-lead ECG 
 
Xab 
 
 
 
 
 
 
 
 
 
 
 
 

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Visita 
 
Procedureb 
Pre-
Screeningc 
Screening 
Chem
o. 
Run-
In 
Period 
Chemo. 
Treatment 
Periodd 
Maintenance Treatment Periodd, e, aa 
EOT 
Safety 
Follow
-Up 
Post-
Treatment 
Assessmenty 
 
 
 
C1 
C2 
C(n) 
C1 
C2 
C(n) 
 
 
 
Day 
-42 to -29 
-28 to -1 
1 
1 
1 
1 
8 
15 
1 
8 
1 
Within 
7 days 
of last 
dose 
30 (±7) 
days 
after 
last 
dose 
Every 
90 (±14) days 
Adverse event 
monitoringg 
 
X 
X 
X 
X 
X 
 
 
X 
 
X 
X 
X 
X 
ECOG performance 
status 
 
Xab 
X 
X 
X 
X 
 
 
X 
 
X 
X 
 
 
Required tumor 
tissue samplesh 
Xh 
Xi 
 
 
Xz 
 
 
 
 
 
 
 
 
 
Blood sample for 
 
 
 
Xj 
Xi 
 
 
 
 
 
 
 
 
 
 
 
 
CBC with 
differentialk 
 
Xab 
Xl 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
 
Coagulation 
 
X ab 
 
As clinically indicatedm 
Blood chemistryn 
 
Xab 
Xl 
X 
X 
X 
 
 
X 
 
X 
X 
X 
 
TSH 
 
X ab 
 
 
 
X 
 
 
 
 
Q6W 
 
 
 
Amylase 
 
 
 
X 
 
X 
 
 
 
 
Q6W 
 
 
 
Serum or urine 
pregnancy testo 
 
Xab 
Xl 
X 
X 
X 
 
 
X 
 
X 
 
X 
 
CCI
CCI
CCI

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Visita 
 
Procedureb 
Pre-
Screeningc 
Screening 
Chem
o. 
Run-
In 
Period 
Chemo. 
Treatment 
Periodd 
Maintenance Treatment Periodd, e, aa 
EOT 
Safety 
Follow
-Up 
Post-
Treatment 
Assessmenty 
 
 
 
C1 
C2 
C(n) 
C1 
C2 
C(n) 
 
 
 
Day 
-42 to -29 
-28 to -1 
1 
1 
1 
1 
8 
15 
1 
8 
1 
Within 
7 days 
of last 
dose 
30 (±7) 
days 
after 
last 
dose 
Every 
90 (±14) days 
HBV/HCV test 
 
X ab 
 
 
 
 
 
 
 
 
 
 
 
 
Serum-based tumor 
markers 
(eg, CA 125)p 
 
Xab 
Xl 
X 
X 
X 
 
 
X 
 
X 
 
 
 
 
 
 
Xq 
Xi 
 
X (before 
IDS) 
X 
 
 
 
 
 
X 
 
 
Blood sample for 
PK/
 
 
 
 
Refer to Table 19 and Table 20. PK sample should be collected at EOT if the participant 
discontinues before completing the final on-treatment PK blood sample collection. 
Urine sample for 
proteinr 
 
X ab 
 
 
 
 
 
 
 
 
 
 
 
 
HRQoL: 
EQ-5D-5L 
EORTC-QLQ-
C30, and 
EORTC-QLQ-
OV28s 
 
 
X 
X 
X 
X 
 
 
X 
 
X 
X 
X 
Xs 
Symptom-directed 
PE 
 
 
X 
X 
X 
X 
 
 
X 
 
X 
 
 
 
CCI
CCI
CCI
CCI

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Visita 
 
Procedureb 
Pre-
Screeningc 
Screening 
Chem
o. 
Run-
In 
Period 
Chemo. 
Treatment 
Periodd 
Maintenance Treatment Periodd, e, aa 
EOT 
Safety 
Follow
-Up 
Post-
Treatment 
Assessmenty 
 
 
 
C1 
C2 
C(n) 
C1 
C2 
C(n) 
 
 
 
Day 
-42 to -29 
-28 to -1 
1 
1 
1 
1 
8 
15 
1 
8 
1 
Within 
7 days 
of last 
dose 
30 (±7) 
days 
after 
last 
dose 
Every 
90 (±14) days 
Randomizationt 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
Concomitant 
medications 
 
X 
X 
X 
X 
X 
X 
X 
X 
 
X 
X 
X 
 
Oral 
niraparib/placebo 
dispensed or 
collected 
 
 
 
 
 
 
 
 
X 
 
X 
X 
 
 
IV dostarlimab 
(Arm 3) or placebo 
(Arms 1 and 2) 
infusionsu 
 
 
 
X 
X 
X 
 
 
 
 
Q6W 
 
 
 
Paclitaxel-carboplat
in infusion (all 
Arms)v 
 
 
X 
X 
X 
 
 
 
 
 
 
 
 
 
Anticancer 
therapies 
assessment 
 
 
 
 
 
 
 
 
 
 
 
 
 
X 
Survival 
assessment 
 
 
 
 
 
 
 
 
 
 
 
 
 
X 

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Visita 
 
Procedureb 
Pre-
Screeningc 
Screening 
Chem
o. 
Run-
In 
Period 
Chemo. 
Treatment 
Periodd 
Maintenance Treatment Periodd, e, aa 
EOT 
Safety 
Follow
-Up 
Post-
Treatment 
Assessmenty 
 
 
 
C1 
C2 
C(n) 
C1 
C2 
C(n) 
 
 
 
Day 
-42 to -29 
-28 to -1 
1 
1 
1 
1 
8 
15 
1 
8 
1 
Within 
7 days 
of last 
dose 
30 (±7) 
days 
after 
last 
dose 
Every 
90 (±14) days 
Bone marrow 
aspirate and biopsy  
 
 
 
For any suspected MDS/AML case reported while on study, a bone marrow 
aspirate/biopsy must be performed by a local hematologist to confirm 
MDS/AML. 
 
RECIST v1.1 
assessment 
Chest/Abdomen/Pe
lvis CT or MRIw, x 
 
Xab 
 
 
Xz 
X 
 
 
 
 
X 
X 
 
 
Abbreviations:
; AE=adverse event; AESI=AE of special interest; AML=acute myeloid leukemia; C=cycle; C1D1=Cycle 1 Day1; 
CA 125=cancer antigen 125; CBC=complete blood count; chemo.=chemotherapy; CT=computed tomography; 
 
ECG=electrocardiogram; ECOG=Eastern Cooperative Oncology Group; EORTC-QLQ-C30=European Organisation for Research and Treatment of Cancer Quality 
of Life Questionnaire C30; EORTC-QLQ-OV28=European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire - Ovarian Cancer 
Module OV28; EOT=end of treatment; EQ-5D-5L=European Quality of Life 5-Dimension 5-Level Scale; 
 
; HBV/HCV=hepatitis B virus/hepatitis C virus; HRQoL=health-related quality of life; 
HRR=homologous recombinant repair; ICF=informed consent; IDS=interval debulking surgery; IV=intravenous; MDS=myelodysplastic syndrome; MRI=magnetic 
resonance imaging; n=number of participants; PD=progressive disease; PE=physical examination; PK=pharmacokinetics; Q6W=every 6 weeks; RECIST=Response 
Evaluation Criteria in Solid Tumors; SAE=serious adverse event, TSH=thyroid stimulating hormone; wks=weeks. 
a Treatment cycles are 21 days long; visits and all assessment should occur within ±3 days of the scheduled visit.  
b All tests and procedures are required to be performed, and results evaluated prior to dosing. 
c The Pre-Screening Period can take place within the 14 days prior to the Screening Period but does not have to encompass the full period. A participant can move to 
the Screening Period once deemed able.  
d All labs in the Chemotherapy Treatment Period and the Maintenance Period may be performed up to -3 days from Day 1 dosing. 
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e In the Maintenance Treatment Period, dostarlimab/placebo IV infusion will start 3 weeks after chemotherapy Cycle 6 Day 1 and will be administered every 
6 weeks thereafter. Hematologic recovery is not required to start dostarlimab/placebo therapy. The start of niraparib will be delayed at least 6 weeks after Cycle 6 Day 
1 and up to 9 weeks after to allow for adequate recovery of hematologic toxicity. Principal Investigators at Maintenance, C1D1 sites should confirm that laboratory 
values remain within the protocol-specified criteria. The Sponsor and 
 will not review these data prospectively. Prior to dosing of study drug, the PI 
must review a CBC, blood chemistry, TSH, and amylase assessment. Review of CA125 prior to dosing is not required. 
f Height will be measured only at Screening. Weight will be measured at Screening and at every visit. Blood pressure, temperature, and heart rate (pulse) will be 
measured at Screening and at every visit. Additionally, BP and heart rate will be performed weekly (±3 days) for the first 8 weeks from the first dose of niraparib in 
the Maintenance Treatment Period (week 1 – first dose [CXM day 1], week 2 – 7 days after first dose [CXM day 8], weekly – weeks 3 to 7], week 8 – 49 days after 
first dose [CX+7M day 1]. 
g All AEs are required to be captured through 30 days after cessation of study treatment. SAEs are required to be captured through 90 days after the last dose of study 
treatment (or for a minimum of 30 days post-treatment discontinuation if the participant starts alternative anticancer therapy). Any pregnancies that occur within 180 
days post-treatment discontinuation are to be captured. Study drug-related SAEs and AESIs will be collected every 90 (±14) days after the last dose of study drug 
until study closeout, or as otherwise indicated in AESI Section 8.2.7. 
h All the participants are required to provide sufficient tumor tissue sample 
. Tumor samples 
must be collected from participants before C1D1. Participants who undergo IDS will be required to provide tumor tissue sample collected from IDS in addition to the 
tumor sample provided at Pre-Screening or Screening.  
i If sample was collected during Pre-Screening, it does not need to be collected again during Screening. 
j Participants must provide blood samples for
 at Pre-Screening or Screening for randomization. For those participants who 
did not provide a 
 at the pre-Screening/Screening stage, a sample may be provided at a later time following Investigator’s 
consultation with the Sponsor. 
k If dose interruption or modification is required at any point on study because of hematologic toxicity, weekly (±3 days) blood draws for CBC will be monitored 
until the AE resolves, and to ensure safety of the new dose, weekly (±3 days) blood draws for CBC will also be required for an additional 4 weeks after the AE has 
been resolved to the specified levels (week 1 - first dose after re-start [CXM day 1], week 2 – 7 days after re-start [CXM day 8], week 3 – 14 days after re-start [CXM 
day 15], week 4 – 21 days after re-start [CX+1M day 1], after which monitoring every 4 weeks may resume. Weekly CBC is required for 4 weeks from the initial 
dose of niraparib (week 1 - first dose [CXM day 1], week 2 – 7 days after first dose [CXM day 8], week 3 – 14 days after first dose [CXM day 15], week 4 – 21 days 
after first dose [CX+1M day 1]. After 1 year of maintenance (after cycle 17), CBC will be done every other cycle. 
l Screening assessments completed within 7 days of the first dose do not need to be repeated. Pregnancy tests completed within 3 days of the first dose do not need to 
be repeated. 
m Coagulation will be collected if required due to an AE. 
n The following blood chemistry parameters will be measured: sodium, potassium, chloride, calcium, magnesium, glucose, total bilirubin, AST, ALT, total protein, 
albumin, creatinine, and urea or blood urea nitrogen. After 1 year of maintenance (after Cycle 17), blood chemistry will be done every other cycle starting with Cycle 
19. 
o For participants of childbearing potential only. 
p After 1 year of maintenance (after cycle 17), CA 125 will be done every other cycle. 
q Samples will be collected at Pre-Screening or Screening, (same time with sample for 
, before IDS, C1D1 of the Maintenance Treatment Period, and at 
the EOT visit.  
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r For participants receiving bevacizumab only: urine dipstick for protein determination should be performed prior to Screening. Participants discovered to have ≥2 
proteinuria on dipstick should not be administered bevacizumab, should undergo a 24-hour urine collection, and must demonstrate <2 g of protein in 24 hours to be 
eligible for bevacizumab treatment. 
s HRQoL assessments will be collected on site on the day of study treatment administration, prior to dosing and clinical procedures, during the treatment period on 
the day of dose administration, prior to dosing and clinical procedures at C1D1, Cycle 2/Day 1, and every 2 cycles thereafter (Cycle 4/Day 1, Cycle 6 Day 1) and 
during the Maintenance Treatment Period at Day 1 of every cycle (i.e., Q21D±7 days) for the first 3 cycles, Day 1 of every 3 cycles (i.e., every 9 weeks±7 days) 
through 15 cycles, Cycle 17 and every 6 cycles thereafter until PD or end of study treatment. For participants who discontinue treatment, HRQoL assessments should 
be collected at the EOT Visit, 30 days post EOT (±7 days) Safety Follow-up Visit, 90-days post EOT (±14 days) Long-Term Follow-up Visit, and every 180 days 
(±14 days) after the 90-day Long-Term Follow-up Visit, which will continue until death or the end of study data collection. HRQoL assessments may occur remotely 
if the participant is no longer actively returning to the clinic. 
t 21 ±7 days after Screening, i.e., during the Chemotherapy Run-In Period but before treatment in Cycle 2. Randomization may occur up to one week prior to Cycle 
2 Day 1. 
u IV dostarlimab/placebo will be administered Q21D (3 weeks) during the Chemotherapy Treatment Period. In the Maintenance Treatment Period, IV 
dostarlimab/placebo will be administered 21 (±3) days (three weeks) after Cycle 6 Day 1 and every 42 days (6 weeks) thereafter. On days that participants receive 
 Participants 
who continue to derive benefit from study treatment based on continuation of best overall response indicated by imaging, remain clinically stable, and are willing to 
continue study visits and assessments may continue to receive niraparib and/or dostarlimab/placebo beyond 3 years following consultation with the investigator and 
the Sponsor. 
v Those participants who are to undergo IDS will receive 3 to 4 cycles of chemotherapy treatment prior to IDS (inclusive of Cycle 1) and an additional 2 to 3 cycles 
following surgery for a maximum of 6 cycles of chemotherapy that cannot be extended. Interval debulking surgery planned after 6 cycles of chemotherapy should be 
discussed with the Sponsor; however, bevacizumab may not be administered less than 28 days before or 28 days following major surgery. 
w RECIST v1.1 tumor assessment via CT or MRI scan of chest/abdomen/pelvis and clinically indicated areas is required at Screening and prior to IDS (if applicable) 
during the Chemotherapy Treatment Period. If there are lesions noted in the chest and/or other clinically indicated areas at Screening, then repeat scans of these areas 
at each follow-up; otherwise, only scans of the abdomen and pelvis are required at each follow-up. During the Maintenance Treatment Period, imaging to assess 
disease status must occur at C1D1 (±14 days) of the Maintenance Treatment Period, and then every 4 months (±7 days) for 24 months, followed by every 6 months 
(±7 days) during the third year and every year thereafter until PD or the initiation of follow-up anticancer therapy. Additional unscheduled scans (of any anatomical 
region that may be clinically indicated) must be performed if participant has increasing CA 125 values or other suspicious symptoms. Imaging modality must be 
consistent with previous assessments whenever feasible. Alternate imaging modalities are allowed for identification of new lesions in anatomical regions that have 
not been previously scanned. 
 
 If a participant discontinues treatment within 28 days of the scan that indicates PD, 
then the EOT scan will not be performed. Following completion of 3 years of maintenance therapy, participants will be evaluated clinically with annual scans and 
additional unscheduled scans for suspicion of disease progression based on increases in CA 125 or other suspicious symptoms. Alternatively, participants may be 
considered for treatment beyond 3 years in consultation with the Sponsor. 
x If participant had CT/MRI of the chest/abdomen/pelvis and clinically indicated areas within the 28-day Screening window before C1D1 but prior to signing the 
main ICF, the participant is not required to complete an additional CT/MRI scan for study Screening. CT/MRI scans completed during Screening prior to signing the 
main ICF must have been performed and available for submission per the image acquisition guidelines. 
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y After the 30-day (±7 days) safety follow-up visit, post-treatment follow-up assessments should be done every 90 days (following the last dose of investigational 
product and/or other study treatments and where allowable can be completed by telephone), as referenced in the table. GSK may request that updated survival data be 
collected on randomized participants outside the protocol window noted in the schedule of events. At the time of the request, the site will determine survival status for 
each participant by the method agreed with the participant, unless the participant has withdrawn consent for survival FU. Public records may be utilized where 
allowed, per local regulations. 
z Applies to those participants who receive IDS only. 
aa After completing 1 year of maintenance treatment (=17 cycles [±1] of niraparib) and 9 cycles [±1] of dostarlimab/placebo, and if not receiving bevacizumab, 
participants may return for clinic visits and assessments every 6 weeks, to coincide with the dostarlimab/placebo IV administration. If receiving bevacizumab, 
following completion of bevacizumab treatment, participants may return for clinic visits and assessments every 6 weeks, to coincide with the dostarlimab/placebo IV 
administration. Participants do not need to return to the clinic Q3W but have the option to return to the clinic every 6 weeks, if preferred. Because both 3- and 6-week 
options are allowed per protocol, this will not lead to protocol deviations. 
ab If participant had the required CT/MRI and/or laboratory assessments within the 28-day Screening window before C1D1 but prior to signing the informed consent 
form (ICF), the participant is not required to complete additional CT/MRI scan and/or laboratory assessments for study. 
 

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Table 18: 
Schedule of Events for Unblinded Participants in Arm 1 who then Receive Niraparib Treatment in Maintenance 
Treatment Period 
Visita 
 
Procedureb 
Maintenance Treatment Periodc, d, p 
EOT 
Safety Follow-Up 
Post-Treatment 
Assessmento 
C1 
C2 
C(n) 
Day 
1 
8 
15 
1 
8 
1 
Within 7 days of 
last dose 
30 (±7) days after last 
dose 
Every 90 (±14) days 
Physical examination 
 
 
 
 
 
 
X 
X 
 
Vital signs and weighte 
X 
X 
X 
X 
X 
X 
X 
 
 
Adverse event 
monitoringf 
X 
 
 
X 
 
X 
X 
X 
X 
ECOG performance 
status 
X 
 
 
X 
 
X 
X 
 
 
CBC with differentialg 
X 
X 
X 
X 
X 
X 
X 
X 
 
Coagulation 
As clinically indicatedh 
Blood chemistryi 
X 
 
 
X 
 
X 
X 
X 
 
Serum or urine 
pregnancy testj 
X 
 
 
X 
 
X 
 
X 
 

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Visita 
 
Procedureb 
Maintenance Treatment Periodc, d, p 
EOT 
Safety Follow-Up 
Post-Treatment 
Assessmento 
C1 
C2 
C(n) 
Day 
1 
8 
15 
1 
8 
1 
Within 7 days of 
last dose 
30 (±7) days after last 
dose 
Every 90 (±14) days 
Serum-based tumor 
markers 
(e.g., CA 125)k 
X 
 
 
X 
 
X 
 
 
 
 
 
X 
 
 
 
 
 
X 
 
 
HRQoL: 
EQ-5D-5L 
EORTC-QLQ-C30, 
and EORTC-QLQ-
OV28m 
X 
 
 
X 
 
X 
X 
X 
X m 
Symptom-directed PE 
X 
 
 
X 
 
X 
 
 
 
Concomitant 
medications 
X 
X 
X 
X 
 
X 
X 
X 
 
Oral niraparib 
dispensed or collected 
X 
 
 
X 
 
X 
X 
 
 
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Visita 
 
Procedureb 
Maintenance Treatment Periodc, d, p 
EOT 
Safety Follow-Up 
Post-Treatment 
Assessmento 
C1 
C2 
C(n) 
Day 
1 
8 
15 
1 
8 
1 
Within 7 days of 
last dose 
30 (±7) days after last 
dose 
Every 90 (±14) days 
Anticancer therapies 
assessment 
 
 
 
 
 
 
 
 
X 
Survival assessment 
 
 
 
 
 
 
 
 
X 
Bone marrow aspirate 
and biopsy 
For any suspected MDS/AML case reported while on study, a bone marrow aspirate/biopsy must be performed by a local 
hematologist to confirm MDS/AML. 
RECIST v1.1 
assessment 
Chest/Abdomen/Pelvis 
CT or MRIn 
X 
 
 
 
 
X 
X 
 
 
Abbreviations: AE=adverse event; AESI=AE of special interest; AML=acute myeloid leukemia; C=cycle; C1D1=Cycle 1 Day 1; CA 125=cancer antigen 125; 
CBC=complete blood count; CT=computed tomography; ECG=electrocardiogram; ECOG=Eastern Cooperative Oncology Group; EORTC-QLQ-C30=European 
Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30; EORTC-QLQ-OV28=European Organisation for Research and Treatment of 
Cancer Quality of Life Questionnaire-Ovarian Cancer Module OV28; EOT=end of treatment; EQ-5D-5L=European Quality of Life 5-Dimension 5-Level Scale; 
 HRQoL=health-related quality of life; HRR=homologous recombinant repair; ICF=informed 
consent form; MDS=myelodysplastic syndrome; MRI=magnetic resonance imaging; n=number of participants; PD=progressive disease; PE=physical examination; 
PK=pharmacokinetics; RECIST=Response Evaluation Criteria in Solid Tumors; SAE=serious adverse event. 
a Treatment cycles are 21 days long; visits and all assessments should occur within ±3 days of the scheduled visit.  
b All tests and procedures are required to be performed, and results evaluated prior to dosing. The Sponsor and
 will not review these data 
prospectively. Prior to dosing of study drug, the PI must review a CBC, blood chemistry, TSH, and amylase assessment. Review of CA 125 prior to dosing is not 
required. 
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c Niraparib will start in the maintenance period upon hematologic recovery. Principal Investigators at C1D1 sites should confirm that laboratory values remain within 
the protocol-specified criteria.  
d All labs in the Maintenance Period may be performed up to -3 days from Day 1 dosing. 
e Weight will be measured at every visit. Blood pressure, temperature, and heart rate (pulse) will be measured at every visit. Additionally, BP and heart rate will be 
performed weekly for the first 8 weeks from the first dose of niraparib in the Maintenance Treatment Period. 
f  All AEs are required to be captured through 30 days after cessation of study treatment. SAEs are required to be captured through 90 days after the last dose of study 
treatment (or to a minimum of 30 days post-treatment discontinuation if the participant starts alternate anticancer therapy). Any pregnancies that occur within 180 
days post-treatment discontinuation are to be captured. Study drug-related SAEs and AESIs will be collected every 90 (±14) days after the last dose of study drug 
until study closeout, or as otherwise indicated in AESI Section 8.2.7. 
g If dose interruption or modification is required at any point on study because of hematologic toxicity, weekly (±3 days) blood draws for CBC will be monitored 
until the AE resolves, and to ensure safety of the new dose, weekly (±3 days) blood draws for CBC will also be required for an additional 4 weeks after the AE has 
been resolved to the specified levels, after which monitoring every 4 weeks may resume. For Maintenance C1, weekly (±3 days) CBC is required for 4 weeks after 
initial dose of niraparib. After 1 year of maintenance (after cycle 17), CBC will be done every other cycle. 
h Coagulation will be collected if required due to an AE. 
i The following blood chemistry parameters will be measured Q21D (±3 days): sodium, potassium, chloride, calcium, magnesium, glucose, total bilirubin, AST, 
ALT, total protein, albumin, creatinine, and urea or blood urea nitrogen. After 1 year of maintenance (after cycle 17), blood chemistry will be done every other 
cycle starting with Cycle 19. 
j For participants of childbearing potential only. 
k After 1 year of maintenance (after cycle 17), CA 125 will be done every other cycle. 
l Samples will be collected at C1D1 of the Maintenance Treatment Period, and at the EOT visit. 
m HRQoL assessments will be collected on site on the day of study treatment administration, prior to dosing and clinical procedures, during the Maintenance 
Treatment Period at Day 1 of every cycle (i.e., Q21D±7 days) for the first 3 cycles, Day 1 of every 3 cycles (i.e., every 9 weeks±7 days) through 15 cycles, Cycle 
17 and every 6 cycles thereafter until PD or end of study treatment. For participants who discontinue treatment, HRQoL assessments should be collected at the 
EOT Visit, 30 days (±7 days) Safety Follow-up Visit, 90-days (±14 days) Long-Term Follow-up Visit, and every 180 days (±14 days) after the 90-day Long-Term 
Follow-up Visit, which will continue until death or the end of study data collection. HRQoL assessments may occur remotely if the participant is no longer actively 
returning to the clinic. 
n If there are lesions noted in the chest and/or other clinically indicated areas at Screening, then repeat scans of these areas at each follow-up; otherwise, only scans of 
the abdomen and pelvis are required at each follow-up. During the Maintenance Treatment Period, imaging to assess disease status must occur at C1D1 (±14 days) 
of the Maintenance Treatment Period, and then every 4 months (±7 days) for 24 months, followed by every 6 months (±7 days) during the third year and every year 
thereafter until PD or the initiation of follow-up anticancer therapy. Additional unscheduled scans (of any anatomical region that may be clinically indicated) must 
be performed if participant has increasing CA 125 values or other suspicious symptoms. Imaging modality must be consistent with previous assessments whenever 
feasible. Alternate imaging modalities are allowed for identification of new lesions in anatomical regions that have not been previously scanned. 
 
 
 If a participant discontinues treatment within 28 days of the scan that indicates PD, then the EOT scan will not be performed. 
Following completion of 3 years of maintenance therapy, participants may be evaluated clinically with annual scans and additional unscheduled scans for suspicion 
of disease progression based on increases in CA 125 or other suspicious symptoms. Alternatively, participants may be considered for treatment beyond 3 years in 
consultation with the Sponsor. 
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o After the 30-day (±7 days) safety follow-up visit, post-treatment follow-up assessments should be done every 90 days (following the last dose of investigational 
product and/or other study treatments and where allowable can be completed by telephone), as referenced in the table. GSK may request that updated survival data 
be collected on randomized participants outside the protocol window noted in the schedule of events. At the time of the request, the site will determine survival 
status for each participant by the method agreed with the participant, unless the participant has withdrawn consent for survival FU. Public records may be utilized 
where allowed, per local regulations. 
p After completing 1 year of maintenance treatment (=17 cycles [±1] of niraparib), participants may return for clinic visits and assessments every 6 weeks. 
 

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APPENDIX 2. PK SAMPLING SCHEDULE 
Table 19: 
Dostarlimab PK and Antidrug Antibodies Sparse Sampling Scheme: Chemotherapy and Maintenance Treatment 
Periods  
Chemotherapy Treatment Period 
(1 Cycle=21 Days) 
Cycle 2 
Cycle 3 
Cycle 4 
Cycle 6 
EOT Visitd 
Safety 
follow-up 
Post-
Treatment 
assessment 
Pre-dostarlimab infusiona, e 
X 
X 
X 
X 
 
 
 
 
End of dostarlimab infusion 
(+30 minutes)b 
X 
 
 
 
 
 
 
Post-dostarlimab infusion (2 hours 
[±30 minutes])c 
X 
 
 
 
 
 
 
Maintenance Treatment Period 
(1 Cycle=21 Days, Dostarlimab 
Dosed Every Other Cycle=42 days) 
Cycle 1 
Cycle 3 
Cycle 7 
Cycle 9 
Cycle 13 
EOT Visitd 
Safety 
follow-up  
Post-
Treatment 
assessment 
Pre-dostarlimab infusiona, e 
X 
X 
X 
X 
X 
 
 
 
End of dostarlimab infusion 
(+30 minutes)b 
X 
 
 
 
 
 
 
 
EOT (Within 7 days of last dose) 
 
 
 
 
 
X 
 
 
Safety follow-up (30±7 days after 
last dose) 
 
 
 
 
 
 
X 
 
Post-Treatment assessment (First 
90±14 days only) 
 
 
 
 
 
 
 
X 
Abbreviations: EOT=End of treatment; PK=pharmacokinetics 
a Sample must be taken within 30 minutes prior to the start of the infusion. 
b Sample must be taken after the end of infusion (30-minute infusion) within a window of +30 minutes. All the PK sampling time points are based 
on the start time of the infusion. 
c Sample must be taken within 2 hours (±30 minutes) after the start of the infusion. All the PK sampling time points are based on the start of the infusion. 
d PK sample should be collected at EOT if the participant discontinues before completing the final on-treatment PK blood sample collection. 

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e If dostarlimab is held or discontinued at a visit that requires dostarlimab PK collection per the table above, a single dostarlimab PK sample (the equivalent to what 
would be the “predose” sample if the participant were receiving treatment) should still be collected. 
Table 20: 
Niraparib PK Sparse Sampling Scheme: Maintenance Treatment Period 
Maintenance Treatment Period (1 Cycle=21 Days, Niraparib 
Dosed QD) 
Cycle 2a 
Cycle 3b 
Cycle 7 
Cycle 9 
Pre-niraparib (within 30 minutes before scheduled dose)c 
X 
X 
X 
X 
Post-niraparib (2 hours [±15 minutes]) 
X 
X 
 
 
Abbreviations: C2D1M=Cycle 2 Day 1, Maintenance; C3D1M=Cycle 3 Day 1, Maintenance; PK=pharmacokinetics; QD=once daily 
a To allow for a 6-week delay from recovery from hematologic toxicity (niraparib dosing begins at C2D1M), niraparib PK sampling will occur on Day 1 of Cycle 2, 
Cycle 3, Cycle 7, and Cycle 9.  
b To allow for a 9-week delay from recovery from hematologic toxicity (niraparib dosing begins at C3D1M), niraparib PK sampling will occur on Day 1 of Cycle 3, 
Cycle 7, and Cycle 9.  
c If niraparib is held or discontinued at a visit that requires niraparib PK collection per the table above, a single niraparib PK sample (the equivalent to what would be 
the “predose” sample if the participant were receiving treatment) should still be collected. 
 

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APPENDIX 3. CONTRACEPTIVE GUIDELINES 
Participants of childbearing potential who are sexually active and their partners must 
agree to the use of 2 highly effective methods of contraception throughout their 
participation during the study treatment and for 180 days after last dose of study 
treatment(s). Acceptable birth control methods include: 
• Combined (estrogen and progestogen containing) hormonal contraception 
associated with inhibition of ovulation: 
− oral route 
− intravaginal route 
− transdermal route 
• Progestogen-only hormonal contraception associated with inhibition of 
ovulation  
− oral 
− injectable 
− implantable  
• Intrauterine device 
• Intrauterine hormone-releasing system 
• Bilateral tubal occlusion 
• Vasectomized partner 
• Sexual abstinence, if the preferred and usual lifestyle of the participant  
 

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APPENDIX 4. RESPONSE EVALUATION CRITERIA IN SOLID 
TUMORS V1.1 
Response Criteria by RECIST v1.1 
Evaluation of Target Lesions 
Complete Response (CR): Disappearance of all target lesions. Any pathological lymph 
nodes (whether target or non-target) must have reduction in short axis to <10 mm. 
Partial Response (PR): At least a 30% decrease in the sum of the diameters of target 
lesions, taking as reference the baseline sum diameters. 
Progressive Disease (PD): At least a 20% increase in the sum of the diameters of target 
lesions, taking as reference the smallest sum on study (this includes the baseline sum if 
that is the smallest on study). In addition to the relative increase of 20%, the sum must 
also demonstrate an absolute increase of at least 5 mm. (Note: the appearance of one or 
more new lesions is also considered progressions.) 
Stable Disease (SD): Neither sufficient shrinkage to qualify for PR nor sufficient 
increase to qualify for PD, taking as reference the smallest sum diameters while on study. 
Evaluation of Non-Target Lesions 
Complete Response (CR): Disappearance of all non-target lesions and normalization of 
tumor marker level. All lymph nodes must be non-pathological in size (<10 mm short 
axis). 
Note: If tumor markers are initially above the upper normal limit, they must normalize for 
a participant to be considered in complete clinical response. 
Non-CR/Non-PD: Persistence of one or more non-target lesion(s) and/or maintenance of 
tumor marker level above the normal limits. 
Progressive Disease (PD): Appearance of one or more new lesions and/or unequivocal 
progression of existing non-target lesions. Unequivocal progression should not normally 
trump target lesion status. It must be representative of overall disease status change, not a 
single lesion increase. 
Although a clear progression of “non-target” lesions only is exceptional, the opinion of 
the treating physician should prevail in such circumstances, and the progression status 
should be confirmed at a later time by the review panel (or Principal Investigator). 
Evaluation of Best Overall Response 
The best overall response is the best response recorded from the start of the treatment 
until disease progression/recurrence (taking as reference for PD the smallest 
measurements recorded since the treatment started). The participant's best response 

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assignment will depend on the achievement of both measurement and confirmation 
criteria. 
As surgery is considered part of the treatment paradigm for participants who receive 
neoadjuvant chemotherapy, all scans that follow IDS (pre-, peri-, or post-maintenance 
scans) are compared to the original baseline (screening) scan [Schwartz, 2016]. If at the 
baseline screening scan, the participant has target lesions ± non-target lesions, then the 
combined response to systemic treatment AND surgery should be reported as: CR, PR, 
SD, PD, or NE. For example, if a participant had a target lesion in the ovary which was 
entirely removed during IDS, and the imaging pre-maintenance did not show any visible 
disease, then the response should be marked as CR. RECIST guidelines above should be 
used to determine PR, SD, or PD. 
If at the baseline screening scan, the participant has non-target lesions only, then the 
combined response to systemic treatment AND surgery should be reported as: CR, non-
CR/non-PD, PD, or NE. 
For SD to be assigned BOR, assessments must have met the SD criteria for a minimum of 
12 consecutive weeks following randomization. If the minimum time for SD is not met, 
BOR will depend on the subsequent assessments. For example, if an assessment of PD 
follows the assessment of SD and SD does not meet the minimum time requirement, the 
best response will be PD. Alternatively, participants lost to follow-up after an SD 
assessment not meeting the minimum time criterion will be considered NE. 
Table 21: 
For Participants with Measurable Disease (i.e., Target Disease) 
Target 
Lesions 
Non-Target Lesions 
New Lesions 
Overall 
Response 
Best Overall 
Response when 
Confirmation is 
Required* 
CR 
CR 
No 
CR 
>4 wks. 
Confirmation** 
CR 
Non-CR/Non-PD 
No 
PR 
>4 wks. 
Confirmation** 
CR 
Not evaluated 
No 
PR 
PR 
Non-CR/Non-PD/not 
evaluated 
No 
PR 
SD 
Non-CR/Non-PD/not 
evaluated 
No 
SD 
Documented at least 
once >12 wks. from 
baseline 
PD 
Any 
Yes or No 
PD 
No prior SD, PR or CR 
Any 
PD*** 
Yes or No 
PD 
Any 
Any 
Yes 
PD 
Abbreviations: CR=complete response; PD=progressive disease; PR=partial response; RECIST=Response; 
Evaluation Criteria in Solid Tumors; SD=stable disease; wks=weeks.  
* 
See RECIST 1.1 manuscript for further details on what is evidence of a new lesion. 
** 
Only for non-randomized trials with response as primary endpoint. 

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*** In exceptional circumstances, unequivocal progression in non-target lesions may be accepted as 
disease progression. 
Note: Participants with a global deterioration of health status requiring discontinuation of treatment without 
objective evidence of disease progression at that time should be reported as “symptomatic 
deterioration.” Every effort should be made to document the objective progression even after 
discontinuation of treatment. 
Table 22: 
For Participants with Non-Measurable Disease (i.e., Non-Target 
Disease) 
Non-Target Lesions 
New Lesions 
Overall Response 
CR 
No 
CR 
Non-CR/non-PD 
No 
Non-CR/non-PD* 
Not all evaluated 
No 
Not Evaluated 
Unequivocal PD 
Yes or No 
PD 
Any 
Yes 
PD 
Abbreviations: CR=complete response; PD=progressive disease; SD=stable disease. 
*‘Non-CR/non-PD’ is preferred over ‘SD’ for non-target disease since SD is increasingly used as an 
endpoint for assessment of efficacy in some trials so to assign this category when no lesions can be 
measured is not advised 
Assessment of New Lesions on the basis of FDG-PET 
New lesions on the basis of FDG-PET imaging can be identified according to the 
following algorithm:  
1. Negative FDG-PET at baseline, with a positive* FDG-PET at follow-up is a sign 
of PD based on a new lesion.  
2. No FDG-PET at baseline and a positive FDG-PET at follow-up:  
If the positive FDG-PET at follow-up corresponds to a new site of disease 
confirmed by CT, this is PD. 
If the positive FDG-PET at follow-up is not confirmed as a new site of disease on CT, 
additional follow-up CT scans are needed to determine if there is truly progression 
occurring at that site (if so, the date of PD will be the date of the initial abnormal FDG-
PET scan).  
If the positive FDG-PET at follow-up corresponds to a pre-existing site of disease on CT 
that is not progressing on the basis of the anatomic images, this is not PD.  
Imaging modality must be consistent with previous assessments whenever feasible. 
Alternate imaging modalities are allowed per RECIST v1.1 for identification of new 
lesions in anatomical regions that have not been previously scanned. 
*A ‘positive’ FDG-PET scan lesion means one which is FDG avid with an uptake greater than twice that of 
the surrounding tissue on the attenuation corrected image. 

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APPENDIX 5. REQUIRED IMAGING 
 
 

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APPENDIX 6. EASTERN COOPERATIVE ONCOLOGY GROUP 
(ECOG) PERFORMANCE STATUS 
Description 
Grade 
Fully active, able to carry on all pre-disease performance without 
restriction. 
0 
Restricted in physically strenuous activity, but ambulatory and able to 
carry out work of a light or sedentary nature, i.e., light housework, 
office work. 
1 
Ambulatory and capable of all self-care but unable to carry out any work 
activities. Up and about more than 50% of waking hours. 
2 
Capable of only limited self-care, confined to bed or chair more than 
50% of waking hours. 
3 
Completely disabled. Cannot carry on any self-care. Totally confined to 
bed or chair. 
4 
Death 
5 
 

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APPENDIX 7. WORLD MEDICAL ASSOCIATION 
DECLARATION OF HELSINKI 
 
The study will be conducted in line with the most recent version of the Declaration of 
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APPENDIX 11. ADAPTATIONS IN STUDY DESIGN 
This study is designed to enable rapid adaptation to evolving treatment paradigms for 
participants with advanced ovarian cancer. This ensures that study participants will have 
access to the most current regimen with or without investigational treatment while 
maintaining the integrity of the study. Full details on adaptations to the study design are 
located in the protocol. 
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As a result, following Sponsor and Steering Committee discussions, participants were not 
enrolled into Arm 1 after Amendment 4 was approved at each site. Participants in Arm 1 
Chemotherapy Treatment Period who are receiving bevacizumab when Amendment 4 is 
implemented, may continue the 6 cycles of chemotherapy. Following completion of the 
Chemotherapy Treatment Period and confirmation of adequate hematologic parameters, 
those participants may start bevacizumab maintenance therapy at the Investigator’s 
discretion. Participants in Arm 1 Maintenance Treatment Period who are receiving 
bevacizumab when Amendment 4 is implemented may continue bevacizumab 
maintenance therapy at the Investigator’s discretion. Investigators will remain blinded for 
those participants enrolled in Arm 1 and receiving bevacizumab at the time of 
implementation of Amendment 4.  
Participants in Arm 1 Chemotherapy Treatment Period not receiving bevacizumab when 
Amendment 4 is implemented, may continue the 6 cycles of chemotherapy. Following 
completion of the Chemotherapy Treatment Period and confirmation of adequate 
hematologic parameters, those participants may start niraparib maintenance therapy as 
"follow-up anticancer treatment" at the Investigator’s discretion. Participants in Arm 1, 
Maintenance Treatment Period not receiving bevacizumab when Amendment 4 is 
implemented may start niraparib maintenance therapy as "follow-up anticancer 
treatment" if the time from Cycle 6 Day 1 of the Chemotherapy Treatment Period is ≤12 
weeks. Participants will be permitted to remain on study until withdrawal of consent, 
sponsor decision to terminate study or death. Participants who do not elect to receive 
niraparib or bevacizumab maintenance will be discontinued from the study treatment and 
given the option to stay in the study for follow up. In order to facilitate this adaptation, 
Investigators will be unblinded for those participants enrolled in Arm 1 and not receiving 
bevacizumab at the time of implementation of Amendment 4. The schedule of events for 
these participants is shown in Table 18. 
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b All participants previously randomized to placebo and not receiving bevacizumab will be unblinded and 
provided the option to receive niraparib maintenance if they have received chemotherapy or discontinued 
chemotherapy ≤12 weeks. 
Prior to implementation of the recommended study adaptation, the Sponsor will amend 
the study and send to appropriate regulatory authorities for approval. Sites will be 
notified when there is an adaptation in the randomization schema. There is no plan to 
hold study enrollment or amend the protocol to accommodate the proposed adaptations 
unless determined to be necessary by the study Steering Committee and/or regulatory 
authorities. 
Determination of the Final Control Group 
The primary efficacy analysis will compare Arm 3 (experimental group) to the 
appropriate control group that was dynamically determined during the study based on 
external data. An important goal of this study was to enable rapid adaptation to evolving 
treatment paradigms in participants with advanced ovarian cancer to ensure that study 
participants had access to the most current regimen or investigational treatment while still 
maintaining the integrity of the study. Amendment 4 confirmed that the control arm for 
the primary efficacy endpoint will be Arm 2.  
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