1005P - Evaluation of niraparib 200 mg/d as maintenance therapy in recurrent ovarian cancer and associated thrombocytopenia in a real-world US setting

Abstract

BackgroundNiraparib, a poly(ADP-ribose) polymerase inhibitor approved in 2017 by the US FDA (300mg/d), has proven to be efficacious as maintenance therapy in patients (pts) with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer (ROC) who are in complete or partial response (PR) to platinum-based chemotherapy (CT), with dose modification recommended to manage adverse reactions. This study assessed the rates of thrombocytopenia (TCP) among ROC pts who initiated niraparib 200mg/d in a real-world US setting. MethodsIn July 2018, we recruited experienced (practicing ≥5 years) oncologists (N=107), who were directly involved in treatment decisions, to complete an online survey and chart review (minimum of 1 and maximum of 2 charts) of adult pts (N=150) with ROC who initiated niraparib 200mg/d within 12 weeks of CT and had ≥3 months of follow-up. Data on pt demographics, disease history, comorbidities, biomarker status (BRCA and homologous recombination deficiency [HRD]), treatment use, and platelet counts (PC) were collected. Data were analyzed using descriptive statistics. ResultsAbout 56% and 44% of pts received 1 and ≥2 lines of CT, respectively, and 55% had a PR to platinum-based CT immediately before niraparib initiation. Pts had stage III (39%) and stage IV (40%) ROC at diagnosis, with a mean disease duration of 1.3 years. BRCA and HRD testing occurred in 87 (58%) and 44 pts (29%), respectively. When asked the reason for initiating niraparib at 200mg/d, 40% of oncologists reported starting all pts at 200mg/d, 37% reported pt preference, 33% reported pt concern of toxicity, and 28% reported pt weight (median: 71kg). Grade 3/4 TCP (per NCI CTCAE v4.03) occurred in 14% of pts post-initiation. Median time from niraparib initiation to the first PC test was 25.5 days. Of 77 pts (51%) with >1PC test, median time from the first to the next test was 28 days. ConclusionsIn this chart review study, <1 in 5 pts had TCP (grade 3/4) and the median time from initiation to PC test was 25.5 days, both of which are lower than observed rates reported in the ENGOT-OV16/NOVA trial. Niraparib dose initiation at 200mg/d may be beneficial in managing adverse reactions in pts with ROC. Legal entity responsible for the studyTesaro: A GSK Company. FundingTesaro: A GSK Company. DisclosureP. Thaker: Research funding: Merck, Tesaro; Grant for research / Consulting: Celsion Pharmaceuticals, AstraZeneca, Tesaro, Merck, AbbVie, Lovance, Unleash Oncolytics, Immunogen, Stryker. K. Travers: Full / Part-time employment: Tesaro: A GSK Company. C. Karki: Full / Part-time employment: Ipsos Insights, LLC. R.P. Patel: Full / Part-time employment: Ipsos Insights, LLC. C. Krebsbach: Full / Part-time employment: Ipsos Insights, LLC. B. Harrow: Full / Part-time employment: Tesaro: A GSK Company. S.N. Westin: Research Funding: ArQule; AstraZeneca; Bayer; Biomarin; Celgene (I); Clovis Oncology; Cotinga Pharmaceuticals; Critical Outcome Technologies; Karyopharm Therapeutics (I); Kite Pharma (I); Novartis; Roche/Genentech; Tesaro; Consulting / Advisory Role: AstraZeneca, BioAscent, Casdin Capital, Clovis Oncology, Genentech, Gerson Lehrman Group, Medivation, Medscape, Merck, Ovation Sciences, Pfizer, Roche, Tesaro, Vaniam Group, Vermillion, Watermark Research Partners.