Real-life data of niraparib maintenance treatment in patients with recurrent platinum-sensitive ovarian cancer.

5560 Background: PARP (poly adenosine diphosphate [ADP]–ribose polymerase) inhibitors are the new standard for maintenance treatment in platinum sensitive recurrent ovarian cancer (PSROC), independent of germline (g-BRCA) or somatic BRCA mutation status. Real-life data after the introduction of new anti-neoplastic agents are needed to evaluate whether the benefit observed in phase III trials can be translated into clinical practice. The aim of this study was to provide real-life data on efficacy and safety of niraparib in non-gBRCA PSROC. Methods: This retrospective multi-center cohort study included patients with PSROC who were enrolled in a national individual patient access program in Norway. Efficacy and safety data were collected from the patients´ electronic medical records. The primary outcome was time from start of niraparib treatment to first subsequent treatment (TFST). Secondary endpoints included prevalence of dose interruption and -reduction, as well as adverse events. Results: The study included 106 patients with median age of 64 years (range 38-81). After median follow up of 15.3 months (95% CI 12.1-18.5), 71 patients (67%) had progressed, 64 (60%) had started a new line of treatment, and 25 (24%) had died. 25 (24%) patients were still receiving niraparib. Median duration of niraparib treatment was 7.6 months (0.4 to 27.3 months). Median TFST was 11.7 months (95% CI 9.2 -14.2). Patients with elevated CA125 after chemotherapy prior to start of niraparib had shorter progression-free survival (PFS) compared to patients with complete serological response (6.5 months (95% CI 5.7 – 7.3) vs 12 months (95% CI 6.2 – 17.9, (p < 0.001)). Grade 3-4 hematologic and non-hematologic events occurred in 25% and 17% of the patients, respectively. The most common grade 3/4 hematologic events were anemia (15%), thrombocytopenia (11%) and neutropenia (8%). Adverse events led to dose interruption in 38% and dose reduction in 44% of the patients. Patients with individualized dosing based on baseline weight and platelet counts had fewer dose reductions (p < 0.001) and -interruptions (p = 0.042) than patients whose dose was not adjusted to those baseline values. Conclusions: In a real-life setting, niraparib maintenance treatment in patients with non-gBRCA PSROC showed efficacy comparable with the published phase III data and an acceptable safety profile. Individualized dosing at start of treatment minimized adverse events. The prolonged PFS in patients with CA125 normalization after last chemotherapy, suggests that these patients in particular benefit from maintenance treatment but warrants confirmation in a larger sample.[Table: see text]