Introduction/Background The PRIMA/ENGOT-OV26/GOG-3012 (PRIMA) trial showed that niraparib significantly improves progression-free survival (PFS) in pts with newly diagnosed advanced OC that responded to first-line platinum-based chemotherapy (CT) (hazard ratio [HR] 0.62; 95% CI 0.50–0.76). Here we discuss the impact of age on efficacy and safety of niraparib.

Methodology This double-blind, placebo (PBO)-controlled phase 3 trial evaluated niraparib in pts with newly diagnosed, advanced, high-grade serous or endometrioid ovarian, primary peritoneal, or fallopian tube cancer with a complete or partial response to first-line platinum-based CT. Pts were randomised 2:1 to receive either a fixed starting dose (FSD) of 300 mg niraparib or PBO QD. A protocol amendment introduced an individualised starting dose (ISD): 200 mg QD in pts with bodyweight <77 kg or platelet count <150,000/μL or 300 mg QD for all others. Pts were dichotomized by age group <65 vs ≥65 years old (yo) to analyse efficacy and safety of niraparib vs PBO in older patients. The primary endpoint was PFS assessed by blinded independent central review.

Results Of 733 enrolled pts, 444 were <65 yo (297 niraparib, 147 PBO), and 289 were ≥65 yo (190 niraparib, 99 PBO). Efficacy was comparable in pts <65 yo (HR 0.61; 95% CI 0.47–0.81) and ≥65 yo (HR 0.53; 95% CI 0.39–0.74) who received niraparib compared with PBO. Any-grade and grade ≥3 treatment emergent adverse events were similar across age groups (table 1). Grade ≥3 thrombocytopenia events in pts <65 yo were reported in 43% of pts receiving a FSD and 18% of pts receiving ISD. In pts ≥65 yo, the values were 57% and 26%, respectively. Patient reported outcomes (PROs) and quality of life (QOL) were similar in both age groups as assessed by FOSI and EQ-5D-5L.

Conclusion Niraparib efficacy, safety, and QOL were similar in compared age groups. Implementation of an ISD regimen improved rates of grade ≥3 thrombocytopenia events in older pts.

Disclosures Funding: GlaxoSmithKline

NCT number: NCT02655016

Encore statement: This data is presented on behalf of the original authors with their permission. Presented at the European Society for Medical Oncology (ESMO) Annual Meeting, September 19–21, 2020, Virtual.

Dr. Dahlstrand reports personal fees from AstraZeneca and Roche.

Dr. Pothuri reports grants, personal fees and non-financial support from GSK; Advisory Board fees from AstraZeneca and Clovis Oncology.

Dr. Graybill reports personal fees from GSK.

Dr. McCormick has nothing to disclose.

Dr. de La Motte Rouge reports personal fees and non-financial support from ASTRAZENECA, MSD, and Roche; personal fees from Clovis Oncology and GlaxoSmithKline; and grants, personal fees, and non-financial support from Pfizer.

Dr. Heitz reports non-financial support from NewOncology; Personal fees from Roche, AstraZeneca, Clovis, Tesaro, and PharmaMar.

Dr. Monk reports consulting and advisory role at Merck, GSK, Roche/Genentech, AstraZeneca, Advaxiz, Cerulean Pharma, Amgen, Immunogen, NuCana BioMed, Clovis Oncology, Pfizer, Mateon Therapeutics, Precision Oncology, Perthera, Abbvie, Myriad Pharmaceuticals, Incyte, VBL Therapeutics, Takeda, Samumed, Oncomed, OncoSec, ChemoID, Geistlich Pharma, Eisai and Chemocare; Speakers’ bureau at Roche/Genentech, AstraZeneca, Janssen, Clovis Oncology and GSK; Honoraria from Merck, GSK, Roche/Genentech, AstraZeneca, Advaxis, Immunogen, NuCana BioMed, Clovis Oncology, Pfizer, Mateon Therapeutics, Precision Oncology, Pethera, Abbvie, Myriad Pharmaceuticals, Incyte, Janssen, Amgen, Genmab, Samumed, Takeda, VBL Therapeutics, Puma Biotechnology, Immunomedics, Conjupro Biotherapeutics, Agenus, OncoQuest, ChemoID, Geistlich Pharma, Eisai and Chemocare; and Research funding from Novartis, Amgen, Genentech, Lilly, Janssen, Array BioPharma, GSK, Morphotek, Pfizer, Advaxis, AstraZeneca, Immunogen, Regeneron, and Nucana.

Dr. González-Martín reports personal fees and non-financial support from AstraZeneca; Grant and personal fees from GSK, Clovis Oncology, Roche Holding AG, Merck & Co., Inc., Genmab, INMUNOGEN, Pharma Mar, S.A., and Oncoinvent AS.

Drs Li and Gupta are employees of GlaxoSmithKline.