Niraparib (Zejula®) is an oral poly (adenosine diphosphate [ADP]–ribose) polymerase (PARP) 1/2 inhibitor that has demonstrated efficacy in patients with platinum-sensitive, recurrent ovarian cancer. Nausea, thrombocytopenia, and fatigue were commonly occurring adverse events (AEs) in the phase 3 clinical trial in which patients were started at 300 mg daily dose of niraparib. After dose adjustments in this trial, a daily dose of 200 mg was the most commonly administered dose. This analysis provides a description of AEs among patients receiving an initial dose of 200 mg niraparib.
In a retrospective observational patient study, 53 randomly selected study-qualified physicians from a national database (61% of qualified physicians screened) extracted requested anonymous information from the medical charts of 153 qualified patients. Qualified patients had received a starting dose of 200 mg/day niraparib for recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer and were in complete or partial response to platinum-based chemotherapy.
Of the 153 patients, 56 (37%) experienced at least one of the three AEs evaluated within the first three months after niraparib initiation, and 49 (32%) experienced only grades 1/2 AEs. Among the 153 patients, fatigue was reported for 24% (36/153) (CI 17.4% - 31.0%); nausea for 16% (25/153) (CI 10.5% - 22.2%) and thrombocytopenia for 14% (21/153) (CI 8.3% - 19.2%). Of the 21 patients with thrombocytopenia, 3 were grade 3/4 severity (2% of overall). Among the patients, 4% (6/153) had a dose interruption, 11% reduced their dose (17/153), and 2% discontinued niraparib altogether (3/153) due to AEs.
While over 60% of patients in the phase 3 clinical trial reported experiencing the three AEs observed in the study, only 37% reported such in real-world usage. This difference may be due to the higher dosing in the trial study (initial dose of 300 mg/day vs. 200 in the observational study). Additional real-world research is needed to understand the effects of niraparib dosing on AEs.
Clinical trial identification
Legal entity responsible for the study
Clarity Pharma Research, LLC.
All authors have declared no conflicts of interest.