Progression-Free Survival and Safety at 3.5 Years of Follow-Up: Results From the Randomized Phase 3 PRIMA/ENGOT-OV26/GOG-3012 Trial of Niraparib Maintenance Treatment in Patients With Newly Diagnosed Ovarian Cancer

Mené sur 733 patientes atteintes d'un cancer de l'ovaire de stade avancé récemment diagnostiqué (durée de suivi : 3,5 ans), cet essai randomisé de phase III évalue l'efficacité, du point de vue de la survie sans progression, et la toxicité du niraparib en traitement d'entretien après réponse complète ou partielle à une chimiothérapie de première ligne à base de sels de platine

Résumé en anglais

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) PFS data (as of 17-Nov-2021) by investigator assessment (INV) are reported.

Results: In 733 randomized patients (niraparib, 487; placebo, 246), median PFS follow-up was 3.5 years. Median INV-PFS was 24.5 vs 11.2 months (hazard ratio, 0.52; 95% CI, 0.40–0.68) in the HRd population and 13.8 vs 8.2 months (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 vs 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% vs 17%; overall, 24% vs 14%). The most common grade ≥3 treatment-emergent adverse events in niraparib patients were thrombocytopenia (39.7%), anemia (31.6%), and neutropenia (21.3%). Myelodysplastic syndromes/acute myeloid leukemia incidence rate (1.2%) was the same for niraparib- and placebo-treated patients. OS 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 progression irrespective of HRD status. No new safety signals were identified.