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 gBRCAm PSROC. The comparative efficacy and safety of different PARPis is currently unknown. An indirect treatment comparison (ITC) analysis of data from the ENGOT-OV16/NOVA and ENGOT-OV21/SOLO2 clinical studies was used to compare niraparib tablets with olaparib tablets.

METHODS: A Bayesian ITC was performed on efficacy and safety data from NOVA (niraparib) and SOLO2 (olaparib). Efficacy data for gBRCAm patients in NOVA were compared with SOLO2. Efficacy analyses included comparing the hazard ratios (HR) of PFS, of investigator-assessed PFS (primary) and independent review committee (IRC)-assessed PFS of SOLO2 versus NOVA, and HR of TFST. Safety analyses included the odds ratio (OR) of any grade ≥3 adverse event (AE), and AEs leading to discontinuation, dose interruption, or dose reduction.

RESULTS: PFS HRs comparing olaparib and niraparib were 1.11 (95% credible interval 0.67–1.83) for investigator-assessed PFS, and 0.93 (0.53–1.61) for IRC PFS. TFST HR was 0.90 (0.54–1.49). No significant difference in efficacy between PARPi was observed. The corresponding OR for AEs was 0.18 (0.07–0.47), 0.30 (0.11–0.79), 0.49 (0.01–6.91) and 0.13 (0.02–0.85) for any grade ≥3 AEs, AEs leading to dose interruption, discontinuation, or reduction, respectively. There was a significant reduction in the odds of any grade ≥3 AE and AEs leading to interruption or dose reduction with olaparib, compared with niraparib.

CONCLUSIONS: ITC shows no significant difference in efficacy between olaparib tablets and niraparib tablets as maintenance therapy in patients with gBRCAm PSROC, following response to chemotherapy. Olaparib is predicted to have had a superior safety profile versus niraparib, with reduced odds of grade ≥3 AEs, drug interruption, and dose reduction.