Durvalumab plus carboplatin/paclitaxel followed by durvalumab with or without olaparib as first-line treatment for newly diagnosed advanced or recurrent endometrial cancer: Japan subset from the phase III DUO-E trial.

Objective: DUO-E/GOG-3041/ENGOT-EN10 (NCT04269200) demonstrated statistically significant and clinically meaningful progression-free survival (PFS) improvement with durvalumab plus carboplatin/paclitaxel, followed by durvalumab with or without olaparib, vs. carboplatin/paclitaxel alone (intention-to-treat [ITT] population) in patients with newly diagnosed advanced or recurrent endometrial cancer. We evaluated efficacy and safety in the Japan subset of DUO-E.

Methods: Patients with newly diagnosed International Federation of Gynecology and Obstetrics stage III/IV or recurrent endometrial cancer were randomized 1:1:1 to control arm (carboplatin/paclitaxel + durvalumab placebo [6 cycles] followed by durvalumab placebo + olaparib placebo), durvalumab arm (carboplatin/paclitaxel + durvalumab [1,120 mg every 3 weeks] [6 cycles] followed by durvalumab [1,500 mg every 4 weeks] + olaparib placebo), or durvalumab + olaparib arm (carboplatin/paclitaxel + durvalumab [6 cycles] followed by durvalumab + olaparib [300 mg twice a day]). Dual primary endpoints were investigator-assessed PFS for durvalumab and durvalumab + olaparib arms vs. control. This prespecified exploratory analysis evaluated PFS and safety in the Japan subset.

Results: In the Japan subset (n=88) PFS favored durvalumab (hazard ratio=0.61, 95% confidence interval [CI]=0.32-1.12) and durvalumab + olaparib (0.44, 95% CI=0.22-0.85) vs. control; median PFS was 9.9 and 15.1 vs. 9.5 months, and the 18-month PFS rate was 37.0% and 42.1% vs. 22.2%, respectively. The safety profile in the Japan subset was generally consistent with the full safety analysis set and the established profiles of the individual agents.

Conclusion: Efficacy and safety in the Japan subset were generally consistent with outcomes in the DUO-E ITT population. This Japanese subset analysis of DUO-E supports carboplatin/paclitaxel + durvalumab followed by durvalumab with or without olaparib as new treatment options in patients with advanced or recurrent endometrial cancer and is the first to report on these regimens in Japanese patients alone.