Retrospective analysis of ovarian cancer patients treated with PARP inhibitors.

Abstract

e17555 Background: Over the last few years, targeted therapy has become the mainstay maintenance treatment of patients with ovarian cancer including patients with BRCA1 or BRCA2 mutations. Poly ADP ribose polymerase (PARP) inhibitors are effective in the treatment of patients who are in complete or partial remission. PARP inhibitors are known to cause hematological adverse events (AEs), but have not been compared directly to each other. Methods: We conducted a single institution, IRB approved, retrospective study on patients who were treated with PARP inhibitors from December 2016 to October 2020. Patients were stratified according to which PARP inhibitor they received. Our primary objective was to assess the incidence of hematological and non-hematological adverse events associated with the use of PARP inhibitor therapy used in patients with ovarian cancer. Data from absolute neutrophil count, hemoglobin and platelet count during the first 2 cycles were graded for hematologic toxicity according to CTCAE v 5.0. Results: A total of 126 patients received a PARP inhibitor during the study time frame. 34 were excluded and 92 patients were included for analysis. Median age of patients were 64.3 (range, 33.8 to 92.3) years, 66 (71.7%) white, and 84 (91.3%) had an ECOG PS of 0/1. Thirty-one (33.7%) of patients received niraparib and 61 (66.3%) of patients received olaparib. Patients in the niraparib group experienced more hematologic AEs, with 11 (35.5%) (95% CI 19.2-54.6), 20 (64.5%) (95% CI 45.4-80.8), and 18 (58.1%) (95% CI 39.1-75.5) experiencing neutropenia, anemia, thrombocytopenia, respectively. Eight (13.1%) (95% CI 5.8-24.2), 24 (39.3%) (95% CI 27.1-52.7), 16 (26.2%) (95% CI 15.8-39.1) patients in the olaparib group experienced neutropenia, anemia, thrombocytopenia, respectively. Conclusions: This single institution retrospective study outlines the hematological toxicities observed between two PARP inhibitors. Although there are four PARP inhibitors approved by FDA, our data compared only two of the four (as they were the most commonly prescribed PARP inhibitors in our institution). Our results suggested that niraparib tended to be associated with a higher risk for hematologic toxicities than olaparib. Our data showed anemia as the most common hematologic toxicity which was consistent with what has been widely documented in the literature.