Cemiplimab plus peltopepimut-S vaccine in recurrent cervical cancer: A phase 2 clinical trial

Objective: To estimate the clinical benefit of cemiplimab+peltopepimut-S vaccine after disease progression on first-line chemotherapy. Methods: This global phase 2 open-label study (NCT04646005) recruited patients with recurrent HPV16+ cervical cancer who had previously experienced disease progression after first-line chemotherapy. Patients received a total of 3 doses of peltopepimut-S vaccine on days 1, 29, and 50 and cemiplimab 350 mg every 3 weeks until disease progression or other reason for early discontinuation. Primary endpoint was objective response rate (ORR) per RECIST version 1.1; secondary endpoints were duration of response (DOR), overall survival (OS), progression-free survival (PFS), and safety. Results: Of 113 patients enrolled between June 28, 2021 and May 22, 2023, 80.5 % were white, with a median age of 49.0 years, and 58.4 % had an ECOG PS of 0. Median duration of follow-up was 4.9 months. ORR (95 % CI) per investigator assessment was 16.8 % (9.9–23.7). ORR of patients with squamous cell carcinoma by PD-L1 expression in tumor cells was 15.8 % for patients with PD-L1 < 1 % and 24.1 % for patients with PD-L1 ≥ 1 %. Median (95 % CI) DOR was 5.6 (3.5–not estimable) months. Median (95 % CI) OS and PFS were 13.3 (10.8–16.3) months and 3.0 (1.7–4.0) months, respectively. Treatment-emergent adverse events (TEAEs) occurred in 92.9 % of patients, the most common being injection-site reaction (38.9 %) and anemia (25.7 %). Six (5.3 %) patients died from a TEAE. Conclusion: Cemiplimab+peltopepimut-S vaccine provides similar benefits to cemiplimab monotherapy; patients with higher PD-L1 expression in tumor cells may be more likely to benefit from treatment.