Long-term safety in patients with recurrent ovarian cancer treated with niraparib versus placebo: Results from the phase III ENGOT-OV16/NOVA trial.

Niraparib is a poly(ADP-ribose) polymerase (PARP) inhibitor approved for use in heavily pretreated patients and as maintenance treatment in patients with newly-diagnosed or recurrent ovarian cancer following a response to platinum-based chemotherapy. We present long-term safety data for niraparib from the ENGOT-OV16/NOVA trial. This multicenter, double-blind, randomized, controlled phase III trial evaluated the efficacy and safety of niraparib for the treatment of recurrent ovarian cancer. Patients were randomly assigned 2:1 to receive either once-daily niraparib 300 mg or placebo. Two independent cohorts were enrolled based on germline BRCA mutation status. The primary endpoint was progression-free survival, reported previously. Long-term safety data were from the most recent data cutoff (September 2017). Overall, 367 patients received niraparib 300 mg once daily. Dose reductions due to TEAEs were highest in month 1 (34%) and declined every month thereafter. Incidence of any-grade and grade ≥ 3 hematologic and symptomatic TEAEs was also highest in month 1 and subsequently declined. Incidence of grade ≥ 3 thrombocytopenia decreased from 28% (month 1) to 9% and 5% (months 2 and 3, respectively), with protocol-directed dose interruptions and/or reductions. Acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) were reported in 2 and 6 niraparib-treated patients, respectively, and in 1 placebo patient each. Treatment discontinuations due to TEAEs were <5% in each month and time interval measured. These data demonstrate the importance of appropriate dose reduction according to toxicity criteria and support the safe long-term use of niraparib for maintenance treatment in patients with recurrent ovarian cancer. ClinicalTrials.gov identifier: NCT01847274. • Long-term safety data for patients from the ENGOT-OV16/NOVA trial is reported. • Grade ≥ 3 thrombocytopenia occurred in 28% of patients in month 1, declining to 9% in month 2. • Dose reductions were highest in month 1 (34%), and declined every month thereafter. • These data support dose reductions according to toxicity criteria and the long-term use of niraparib maintenance treatment. [ABSTRACT FROM AUTHOR]