OVARIO phase II trial of combination niraparib plus bevacizumab maintenance therapy in advanced ovarian cancer following first-line platinum-based chemotherapy with bevacizumab

Objective: To assess safety and efficacy of niraparib + bevacizumab as a first-line maintenance therapy for patients with newly diagnosed advanced ovarian cancer. Methods: This multicenter, phase II, single-arm, open-label study enrolled adult patients with stage IIIB to IV ovarian, fallopian tube, or primary peritoneal cancer (NCT03326193). Patients were required to have an attempt at debulking surgery and have a complete response, partial response, or no evidence of disease following first-line, platinum-based chemotherapy with ≥3 cycles of bevacizumab. The primary endpoint was the progression-free survival (PFS) rate at 18 months. Secondary endpoints included PFS, overall survival, and safety. Results: Among the 105 evaluable patients, the PFS rate at 18 months was 62% (95% CI 52–71%) in the overall population and 76% (95% CI 61–87) in the homologous recombination deficient (HRd), 47% (95% CI 31–64%) in the HR proficient (HRp), and 56% (95% CI 31–79%) in the HR not determined (HRnd) subgroups (December 24, 2020, cutoff). After a median follow-up time of 28.7 months (IQR, 23.9–32.5 months), median PFS was 19.6 months (95% CI 16.5–25.1) in the overall population (N = 105) and 28.3 months (95% CI 19.9–NE), 14.2 months (95% CI 8.6–16.8), and 12.1 months (95% CI 8.0–NE) in the HRd, HRp, and HRnd subgroups, respectively (June 16, 2021, cutoff). The most common any-grade treatment-related adverse events (related to niraparib and/or bevacizumab) were thrombocytopenia (74/105), fatigue (60/105), and anemia (55/105; December 24, 2020, cutoff). Conclusion: Niraparib + bevacizumab first-line maintenance therapy displayed promising PFS results. Safety was consistent with the known safety profiles of niraparib and bevacizumab as monotherapy.