As reported in the Journal of Clinical Oncology by Harter et al, the final results of a European phase III trial (AGO-OVAR 2.29/ENGOT-ov34) showed no significant overall or progression-free survival benefit with the addition of atezolizumab to bevacizumab and nonplatinum chemotherapy in patients with recurrent ovarian cancer.
Study Details
Five hundred and sixty-seven patients from sites in 12 European countries were enrolled in the double-blind trial. They randomly assigned between September 2018 and July 2022 to receive atezolizumab at 840 mg (n = 281) or placebo (n = 286) on days 1 and 15 of 28-day cycles for up to 2 years combined with bevacizumab (at 10 mg/kg on days 1 and 15) and nonplatinum chemotherapy (investigator choice of once-weekly paclitaxel at 80 mg/m2 on days 1, 8, 15, and 22 or pegylated liposomal doxorubicin at 40 mg/m² on day 1) given until disease progression or unacceptable toxicity. All patients were in first or second relapse of disease ≤ 6 months after completing platinum-based chemotherapy (or third relapse regardless of treatment-free interval). Among all patients, 72% were bevacizumab-pretreated, 36% had received three previous treatment lines, and 26% had PD-L1–positive tumors. A total of 54% of participants received paclitaxel as study chemotherapy. The primary endpoints of the study were overall survival and progression-free survival.
Key Findings
Median follow-up for overall survival was 26.9 months (interquartile range = 20.5–31.4 months), corresponding to 73% maturity. Median overall survival was 14.2 months (95% confidence interval [CI] = 13.0–16.1 months) in the atezolizumab group vs 13.0 months (95% CI = 11.9–15.1 months) in the placebo group (hazard ratio [HR] = 0.83, 95% CI = 0.68–1.01, P = .06). Rates at 2 years were 31% vs 23%. Hazard ratios were similar regardless of PD-L1 status. The hazard ratio favored the atezolizumab group among patients receiving paclitaxel (0.75, 95% CI = 0.57–0.98).
Median progression-free survival was 6.4 months (95% CI = 6.1–7.8 months) in the atezolizumab group vs 6.7 months (95% CI = 6.2–8.1 months) in the placebo group (HR = 0.87, 95% CI = 0.73–1.04, P = .12).
Grade ≥ 3 adverse events occurred in 72% of the atezolizumab group vs 69% of the placebo group, with 23% vs 12% considered related to atezolizumab vs placebo. Adverse events led to the discontinuation of atezolizumab in 16% of patients and placebo in 14%, and to the discontinuation of bevacizumab in 22% vs 19%.
The investigators concluded: “Combining atezolizumab with bevacizumab and chemotherapy did not significantly improve [overall survival or progression-free survival] in patients with recurrent ovarian cancer ineligible for platinum. The safety profile was as expected from previous experience with these drugs.”
Philipp Harter, MD, of Kliniken Essen-Mitte, Essen, Germany, is the corresponding author for the Journal of Clinical Oncology article.
DISCLOSURE: The study was supported by F. Hoffmann–La Roche Ltd. For full disclosures of the study authors, visit ascopubs.org.
