Cemiplimab monotherapy in Japanese patients with recurrent or metastatic cervical cancer

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.