Niraparib first-line maintenance therapy in patients with newly diagnosed advanced ovarian cancer: final overall survival results from the PRIMA/ENGOT-OV26/GOG-3012 trial

Abstract

The phase 3 PRIMA/ENGOT-OV26/GOG-3012 trial met its primary endpoint. Niraparib first-line maintenance significantly prolonged progression-free survival (PFS) among patients with newly diagnosed advanced ovarian cancer (aOC) that responded to first-line platinum-based chemotherapy, regardless of homologous recombination deficiency (HRD) status. Final overall survival (OS) results are reported. Patients were randomized 2:1 to niraparib or placebo, stratified by response to first-line treatment, receipt of neoadjuvant chemotherapy, and tumor HRD status. After reaching 60% target maturity, OS was evaluated via a stratified log-rank test using randomization stratification factors and summarized using Kaplan-Meier methodology. OS testing was hierarchical (overall population first, then the homologous recombination-deficient [HRd] population). Other secondary outcomes and long-term safety were assessed; an updated, ad hoc analysis of investigator-assessed PFS was also conducted (cutoff date, 08Apr2024). Median follow-up was 73.9 months. In the overall population, the OS hazard ratio (HR) was 1.01 (95% CI, 0.84-1.23; P= 0.8834) for niraparib (n= 487) versus placebo (n;= 246). In the HRd (n= 373) and homologous recombination-proficient (n= 249) populations, the OS HRs were 0.95 (95% CI, 0.71-1.29) and 0.93 (95% CI 0.69-1.26), respectively. Subsequent poly(ADP-ribose) polymerase inhibitor therapy was received by 11.7% and 15.8% of niraparib patients and 37.8% and 48.4% of placebo patients in the overall and HRd populations, respectively. The 5-year PFS rate numerically favored niraparib in the overall (niraparib, 22%; placebo, 12%) and HRd populations (niraparib, 35%; placebo, 16%). Myelodysplastic syndromes/acute myeloid leukemia incidence was <2.5% (niraparib, 2.3%; placebo, 1.6%). No new safety signals were observed. In patients with newly diagnosed aOC at high risk of recurrence, there was no difference in OS between treatment arms. In the HRd population, patients alive at 5 years were twice as likely to be progression free with niraparib treatment than placebo. Long-term safety remained consistent with the established niraparib safety profile.