Progression-free survival and safety at 3.5years 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

Eur J Cancer. 2023 Aug:189:112908. doi: 10.1016/j.ejca.2023.04.024. Epub 2023 May 3.


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 regimen (CR/PR), receipt of neoadjuvant chemotherapy (yes/no), and homologous recombination deficiency (HRD) status (deficient [HRd]/proficient [HRp] or not determined). Updated (ad hoc) progression-free survival (PFS) data (as of November 17, 2021) by investigator assessment (INV) are reported.

Results: In 733 randomised patients (niraparib, 487; placebo, 246), median PFS follow-up was 3.5years. Median INV-PFS was 24.5 versus 11.2months (hazard ratio, 0.52; 95% confidence interval [CI], 0.40-0.68) in the HRd population and 13.8 versus 8.2months (hazard 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 5.4months (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 4years than placebo-treated patients (HRd, 38% versus 17%; overall, 24% versus 14%). The most common grade ≥ 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 3.5years of follow-up in patients with newly diagnosed advanced ovarian cancer at high risk of progression irrespective of HRD status. No new safety signals were identified.

Keywords: Advanced ovarian cancer; Maintenance therapy; Niraparib; PARP inhibitor.

Publication types

  • Clinical Trial, Phase III
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carcinoma, Ovarian Epithelial / drug therapy
  • Female
  • Humans
  • Indazoles / adverse effects
  • Maintenance Chemotherapy / methods
  • Ovarian Neoplasms* / drug therapy
  • Progression-Free Survival


  • niraparib
  • Indazoles

Associated data