519MO Phase III EMPOWER-Cervical 1/GOG-3016/ENGOT-cx9 trial of cemiplimab in recurrent or metastatic (R/M) cervical cancer: Long-term survival analysis

Abstract

Interim overall survival (OS) analysis from the Phase 3 EMPOWER-Cervical 1 study showed that cemiplimab monotherapy significantly improved OS vs investigator’s choice (IC) single-agent chemotherapy (chemo) in patients (pts) with R/M cervical cancer after progression on first-line (1L) platinum-based chemo (median follow-up: 18.2 months). Cemiplimab had an acceptable safety profile, with Grade ≥3 adverse events occurring in 45.0% of cemiplimab-treated pts vs 53.4% of chemo-treated pts. We report the final survival analysis after a further 1-year of follow-up. 608 pts enrolled regardless of programmed cell death ligand 1 (PD-L1) status were randomised (1:1) to cemiplimab 350 mg IV Q3W or IC single-agent chemo for up to 96 weeks. Randomisation was stratified by histology (squamous cell carcinoma [SCC] or adenocarcinoma including adenosquamous carcinoma [AC]), ECOG performance status score, prior bevacizumab use, and geographic region. Primary endpoint was OS, analysed hierarchically in pts with SCC followed by overall population. Exploratory analyses of OS in pts with AC and OS by PD-L1 expression were performed. In this analysis, 371 (61.0%) pts had tumor samples evaluable for PD-L1 expression vs 254 (41.8%) pts in the prior analysis. We report OS for both PD-L1 populations. Data cutoff is Jan 4, 2022. Median (range) duration of follow-up was 30.2 (18.0–50.2) months. Cemiplimab significantly improved OS vs chemo, lowering risk of death by 31% and 34% in SCC and overall populations, respectively (Table). In the AC population, cemiplimab increased OS vs chemo with 45% lower risk of death. In the n=254 and n=371 PD-L1 populations, those with PD-L1 ≥1% and PD-L1 <1% had longer OS vs chemo.Table: 519MOPopulationCemiplimab median OS months (n)IC chemo median OS months (n)Hazard ratio for death (95% confidence interval)P valueSCC population10.9 (n=239)8.8 (n=238)0.69 (0.56‒0.85)P=0.00023Overall population11.7 (n=304)8.5 (n=304)0.66 (0.55–0.79)P<0.00001AC population*13.5 (n=65)7.0 (n=66)0.55 (0.37‒0.81)-PD-L1 population (n=254)*PD-L1 ≥1%13.9 (n=82)9.3 (n=80)0.70 (0.48–1.01)-PD-L1 <1%8.2 (n=44)6.7 (n=48)0.85 (0.53–1.36)-PD-L1 population (n=371)*PD-L1 ≥1%12.1 (n=116)7.7 (n=121)0.61 (0.45–0.83)-PD-L1 <1%10.8 (n=66)7.0 (n=68)0.65 (0.43–0.98)-*Analysis of OS in the AC population and PD-L1 population subsets were exploratory with no adjustments for multiplicity. Open table in a new tab *Analysis of OS in the AC population and PD-L1 population subsets were exploratory with no adjustments for multiplicity. With long-term follow-up, cemiplimab continues to show, in the overall population, a statistically significant and clinically meaningful improvement in OS vs chemo in pts with R/M cervical cancer after 1L platinum-based chemo.