Objective: To assess patient-reported health-related quality of life (HRQoL) in patients with ovarian cancer (OC) who received niraparib as first-line maintenance therapy., Methods: PRIMA/ENGOT-OV26/GOG-3012 (NCT02655016) enrolled patients with newly diagnosed advanced OC who responded to first-line platinum-based chemotherapy. Patients were randomized (2:1) to niraparib or placebo once daily in 28-day cycles until disease progression, intolerable toxicity, or death. HRQoL was assessed as a prespecified secondary end point using patient-reported responses to the European Organisation for Research and Treatment of Cancer QOL Questionnaire (EORTC QLQ-C30), the EORTC QLQ Ovarian Cancer Module (EORTC QLQ-OV28), the Functional Assessment of Cancer Therapy-Ovarian Symptom Index (FOSI), and EQ-5D-5L questionnaires. Assessments were collected at baseline and every 8 weeks (±7 days) for 56 weeks, beginning on cycle 1/day 1, then every 12 weeks (±7 days) thereafter while the patient received study treatment., Results: Among trial participants (niraparib, n = 487; placebo, n = 246), PRO adherence exceeded 80% for all instruments across all cycles. Patients reported no decline over time in HRQoL measured via EORTC QLQ-C30 Global Health Status/QoL and FOSI overall scores. Scores for abdominal/gastrointestinal symptoms (EORTC QLQ-OV28) and nausea and vomiting, appetite loss, and constipation (EORTC QLQ-C30) were higher (worse symptoms) in niraparib-treated patients than placebo-treated patients; except for constipation, these differences resolved over time. Patients did not self-report any worsening from baseline of fatigue, headache, insomnia, or abdominal pain on questionnaires., Conclusions: Despite some early, largely transient increases in gastrointestinal symptoms, patients with OC treated with niraparib first-line maintenance therapy reported no worsening in overall HRQoL., Competing Interests: Declaration of competing interest Dr. Pothuri reports institutional grant support from AstraZeneca, Celsion, Clovis Oncology, Eisai, Genentech/Roche, GSK, I-Mab, Immunogen, Incyte, Karyopharm, Merck, Mersana, Onconova, Seagen, Sutro Biopharma, and Toray; consulting fees from AstraZeneca, GSK, GOG Foundation, Merck, and Seagen; support for attending meetings from GOG Partners; advisory board fees from Arquer Diagnostics, Atossa, Clovis Oncology, Deciphera, Eisai, Elevar Therapeutics, GOG Foundation, I-Mab, Immunogen, Lily, Merck, Mersana, Natera, Onconova, Regeneron, Sutro Biopharma, Tesaro/GSK, Toray, and VBL Therapeutic. Dr. Han has nothing to disclose. Dr. Chase reports consultant fees from AstraZeneca and GSK, and honoraria from AstraZeneca, GSK, Immunogen, and Seagen/Genmab. Dr. Heitz reports honoraria from AstraZeneca, GSK, Roche, and Tesaro; consulting fees from AstraZeneca, GSK, Roche, and Tesaro. Dr. Burger reports receiving travel support from Genentech and Mersana Therapeutics, stock from Genentech and Mersana Therapeutics, and is an employee of Genentech and Mersana Therapeutics. Dr. Gaba reports consulting fees, advisory board, and honoraria fees from AstraZeneca, Clovis Oncology, GSK, MSD, and PharmaMar, and support for attending meetings from AstraZeneca, Clovis Oncology, GSK, and MSD. Dr. Van Le has nothing to disclose. Dr. Guerra reports AstraZeneca, Clovis Oncology, GSK, Merck, Pharmamar, Roche, and Tesaro; honoraria from AstraZeneca, Clovis Oncology, GSK/Tesaro, and Merck; payment for expert testimony from AstraZeneca, Clovis Oncology, GSK, Merck, Tesaro; travel support from GSK, Roche, and Tesaro; advisory board participation for AstraZeneca, GSK, Merck, and Tesaro. Dr. Bender reports institutional grants from AbbVie, AstraZeneca, Clovis Oncology Inc., Genentech, MSD, and Tesaro. Dr. Korach serves in a leadership role for ISGO. Dr. Cloven reports advisory board fees from Aadii, GSK, Kartos 2022, Novita Pharmaceuticals 2023, Tarveda Therapeutics, Toray, Umoja 2022, and Zentalis. Dr. Churruca reports payment for expert testimony from PharmaMar and support for attending meetings from GSK, and MSD. Dr. Follana reports payment for expert testimony from AstraZeneca, Clovis, Daiichi, GSK, and Novartis; and support for attending meetings from AstraZeneca, Daiichi, GSK, and Novartis. Dr. DiSilvestro reports consulting fees from AstraZeneca, GSK, and Immunogen; travel support from AstraZeneca; and leadership roles in the GOG Foundation Board of Directors and NRG Oncology Board of Directors. Dr. Baurain reports consulting fees from AstraZeneca, Bristol-Myers Squibb, GSK, Immunocore, Merck, MSD, Novartis, Pfizer, Pierre-Fabre, Regeneron, Sanofi, and Sun Pharma. Dr. Jardon has nothing to disclose (deceased). Dr. Pisano has nothing to disclose. Dr. Peen has nothing to disclose. Dr. Mäenpää reports honoraria from AstraZeneca, Eisai, and GSK. Dr. Gupta was an employee of GSK at the time the analysis was conducted; currently an employee of Mersana Therapeutics. Dr. Bacqué was an employee of GSK at the time the analysis was conducted; currently an employee of Repare Therapeutics. Dr. Li was an employee of GSK at the time the analysis was conducted and reports GSK stock ownership; currently an employee of Adagio Therapeutics. Ms. Compton is a former employee of GSK and currently receiving consulting fees from GSK. Dr. Antonova is a former employee of GSK. Dr. Monk reports consulting fees from Agenus, Akeso Biopharma, Amgen, Aravive, Bayer, Elevar, EMD Merck, Genmab/Seagen, GOG Foundation, Gradalis, ImmunoGen, Iovance, Karyopharm, MacroGenics, Mersana, Myriad, Novartis, Novocure, Pfizer, Puma, Regeneron, Sorrento, US Oncology Research, and VBL; and speakers' bureau honoraria from AstraZeneca, Clovis, Eisai, Merck, Roche/Genentech, and Tesaro/GSK. Dr. González-Martín reports manuscript funding from GSK; research/grant funding from Roche and Tesaro/GSK; advisory/consulting fees from Alkermes, Amgen, AstraZeneca, Clovis Oncology, Genmab, GSK, HederaDx, ImmunoGen, Illunina, MacroGenics, Mersana, MSD, Novartis, Novocure, Oncoinvent, Pfizer/Merck, PharmaMar, Roche, Seagen, Sotio, Sutro, Takeda, and Tubuli; speaker bureau fees from AstraZeneca, Clovis Oncology, GSK, PharmaMar, and Roche; and support for attending meetings from AstraZeneca, GSK, PharmaMar, and Roche., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)