Atezolizumab combined with platinum-based chemotherapy and maintenance niraparib failed to demonstrate a statistically significant improvement in progression-free survival (PFS) for patients with late-relapsing recurrent ovarian cancer, according to results from the phase III ENGOT-OV41/GEICO 69-O/ANITA trial. The study, a double-blind multicenter trial conducted across Europe, randomized 417 patients with recurrent ovarian cancer who had a platinum-free interval greater than 6 months. The results were published in the Journal of Clinical Oncology.
Patients were randomized to receive either atezolizumab (n = 208) or placebo (n = 209) in combination with an investigator-selected platinum doublet (carboplatin with paclitaxel, gemcitabine, or pegylated liposomal doxorubicin) for six cycles, followed by niraparib maintenance in patients who achieved an objective response or stable disease. The primary endpoint was investigator-assessed progression-free survival.
Key Findings on Efficacy
With a median follow-up of 28.6 months (95% CI = 26.6–30.5 months), the median progression-free survival was 11.2 months (95% CI = 10.1–12.1 months) in the atezolizumab group compared to 10.1 months (95% CI = 9.2–11.2 months) in the control group (hazard ratio [HR] = 0.89, 95% CI = 0.71–1.10, P = .28). Subgroup analyses, including PD-L1 expression subgroups, showed generally similar outcomes.
Among the 306 patients who initiated maintenance therapy, the median maintenance progression-free survival was 6.7 months with atezolizumab/niraparib versus 5.3 months with placebo/niraparib (HR = 0.80, 95% CI = 0.62–1.03). Objective response rates were 45% in the atezolizumab arm and 43% in the placebo arm. Stable disease was observed in 44% and 46% of patients, respectively.
Safety Profile
Treatment-related grade ≥ 3 adverse events occurred in 65% of patients in the atezolizumab group and 63% in the placebo group. Serious adverse events were reported in 37% and 30% of patients, respectively. According to the investigators, the safety profile was consistent with previous experience with these drugs.
Implications of the Study
The study's lead author, Antonio González-Martín, MD, of Cancer Center Clínica Universidad de Navarra, Madrid, concluded that combining atezolizumab with chemotherapy and maintenance niraparib did not significantly improve progression-free survival or the objective response rate in patients with late-relapsing recurrent ovarian cancer. The trial was funded by F. Hoffmann-La Roche Ltd and GlaxoSmithKline.
