Progression-free survival and safety at 3.5 years of follow-up: results from the randomised phase 3 PRIMA/ENGOT-OV26/GOG-3012 trial of niraparib maintenance treatment in patients with newly diagnosed ovarian cancer

Purpose: To report updated long-term efficacy and safety from the double-blind, placebo-controlled, phase 3 PRIMA/ENGOT-OV26/GOG-3012 study (NCT02655016).Methods: Patients with newly diagnosed advanced ovarian cancer with complete or partial response (CR or PR) to first-line platinum-based chemotherapy received niraparib or placebo once daily (2:1 ratio). Stratification factors were best response to first-line chemotherapy re-gimen (CR/PR), receipt of neoadjuvant chemotherapy (yes/no), and homologous re-combination deficiency (HRD) status (deficient [HRd]/proficient [HRp] or not determined). Updated (ad hoc) progression-free survival (PFS) data (as of November 17, 2021) by in-vestigator assessment (INV) are reported. Results: In 733 randomised patients (niraparib, 487; placebo, 246), median PFS follow-up was 3.5 years. Median INV-PFS was 24.5 versus 11.2 months (hazard ratio, 0.52; 95% confidence interval [CI], 0.40-0.68) in the HRd population and 13.8 versus 8.2 months (ha-zard ratio, 0.66; 95% CI, 0.56-0.79) in the overall population for niraparib and placebo, respectively. In the HRp population, median INV-PFS was 8.4 versus 5.4 months (hazard ratio, 0.65; 95% CI, 0.49-0.87), respectively.Results were concordant with the primary analysis. Niraparib-treated patients were more likely to be free of progression or death at 4 years than placebo-treated patients (HRd, 38% versus 17%; overall, 24% versus 14%). The most common grade & GE; 3 treatment-emergent adverse events in niraparib patients were thrombocytopenia (39.7%), anaemia (31.6%), and neutropenia (21.3%). Myelodysplastic syndromes/acute myeloid leukaemia incidence rate (1.2%) was the same for niraparib-and placebo-treated patients. Overall survival remained immature.Conclusions: Niraparib maintained clinically significant improvements in PFS with 3.5 years of follow-up in patients with newly diagnosed advanced ovarian cancer at high risk of pro-gression irrespective of HRD status. No new safety signals were identified.& COPY; 2023 Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study reports the long-term efficacy and safety of the PRIMA/ENGOT-OV26/GOG-3012 trial. The results show that niraparib maintains clinically significant improvements in progression-free survival (PFS) in high-risk patients with newly diagnosed advanced ovarian cancer, regardless of HRD status. No new safety signals were identified.