Cemiplimab monotherapy in Japanese patients with recurrent or metastatic cervical cancer

Abstract Background In the phase 3 EMPOWER‐Cervical 1/GOG‐3016/ENGOT‐cx9 study, cemiplimab significantly improved overall survival (OS) versus chemotherapy for patients with recurrent or metastatic cervical cancer who progressed after first‐line platinum‐based chemotherapy. We present a post hoc subgroup analysis of patients enrolled in Japan. Methods Patients were enrolled regardless of programmed cell death‐ligand 1 status and randomized 1:1 to cemiplimab 350 mg intravenously every 3 weeks or investigator's choice single‐agent chemotherapy for up to 96 weeks. Primary endpoint was OS. Key secondary endpoints were progression‐free survival (PFS) and objective response rate (ORR). Results Overall, 608 patients were randomized, of whom 56 (9.2%) were in Japan (cemiplimab, n = 29; chemotherapy, n = 27). The median (range) duration of follow‐up was 13.6 (6.0–25.3) versus 18.2 (6.0–38.2) months for patients in Japan and for the overall population, respectively. Median OS (95% confidence interval [CI]) was 8.4 (7.0‐not evaluable) and 9.4 (5.4–14.9) months for cemiplimab versus chemotherapy (hazard ratio [HR]: 0.86; 95% CI: 0.43–1.68). Median PFS (95% CI) was 4.0 (1.4–8.2) versus 3.7 (1.8–4.2) months with cemiplimab and chemotherapy (HR: 0.90; 95% CI: 0.50–1.61), respectively. ORR was 17.2% for cemiplimab and 7.4% for chemotherapy (odds ratio, 2.47; 95% CI, 0.44–13.99). Incidence of treatment‐emergent adverse events at any grade was 79.3% for cemiplimab and 100% for chemotherapy. Grade ≥3 adverse events were 37.9% versus 66.7% with cemiplimab and chemotherapy, respectively. Discussion While acknowledging limitations inherent to a small subgroup analysis, the HR of 0.86 observed in Japanese patients suggests an emerging survival benefit despite a 4.6‐month shorter median duration of follow‐up versus the overall study population.