OBJECTIVES: Maintenance therapy with a poly(ADP-ribose) polymerase inhibitor (PARPi), following response to platinum-based chemotherapy, significantly extends progression-free survival (PFS) and time to first subsequent treatment or death (TFST) in germline BRCA-mutated (gBRCAm) platinum-sensitive relapsed ovarian cancer (PSROC). Statistically significant treatment benefit has also been observed in patients without a gBRCAm, suggesting sensitivity to PARPis in non-gBRCAm patients. Comparative efficacy and safety of different PARPis in non-gBRCAm is currently unknown. An indirect treatment comparison (ITC) of niraparib tablets and olaparib capsules, using data from ENGOT-OV16/NOVA and Study 19 (NCT00753545/S19) clinical studies, respectively, was conducted.

METHODS: A Bayesian ITC was performed on efficacy and safety on the non-gBRCA data from NOVA (niraparib) and gBRCA wild type data from S19 (olaparib). Efficacy analyses compared investigator (INV) and independent review committee (IRC) assessed PFS hazard ratios (HR) and TFST HR. Safety analyses included odds ratios (OR) of any grade ≥3 adverse event (AE), AEs leading to dose interruption, reduction, and discontinuation.

RESULTS: HRs comparing olaparib and niraparib were 0.94 (95% credible interval 0.54–1.65) for investigator-assessed PFS, and 1.25 (0.67–2.30) for IRC PFS. TFST HR was 0.78 (0.47–1.30). No significant difference in efficacy between PARPi was observed. The corresponding ORs for AE were 0.34 (0.13–0.90), 0.54 (0.16–2.06), 0.16 (0.01–2.18) and 0.21 (0.04–1.21) for any grade ≥3 AE, and AE leading to dose interruption, discontinuation, and reduction, respectively. There was a significant reduction in the odds of any grade ≥3 AE. No significant difference in AE leading to dose interruption, reduction, and discontinuation.

CONCLUSIONS: ITC shows no significant difference in efficacy between olaparib capsules and niraparib tablets as maintenance therapy in patients with non-gBRCAm PSROC following response to chemotherapy. Olaparib shows significantly reduced odds compared with niraparib for any grade ≥3 AE. No significant difference was observed in AEs leading to modification in drug administration.