Multinational phase 2 trial of cemiplimab once every four weeks for advanced cutaneous squamous cell carcinoma

Cemiplimab is a PD-1 inhibitor approved for the treatment of patients with advanced cutaneous squamous cell carcinoma (aCSCC), who are not candidates for curative surgery or radiation, using an every-3-weeks (Q3W) dosing interval. Pharmacokinetic modeling indicated that C_through of extended intravenous dosing of 600 mg Q4W would be comparable to the approved intravenous dosage of 350 mg Q3W. A multinational phase 2 trial evaluated cemiplimab 600 mg Q4W for aCSCC. The study included 63 patients. The median duration of follow-up was 22.4 months (range 1.0-39.8). An objective response was observed in 39 patients (62%; 95% CI 48.8-73.9), with complete response in 14 patients (22%). The most common treatment-emergent adverse events were diarrhea, pruritus, and fatigue. The authors conclude that cemiplimab 600 mg Q4W exhibited substantial antitumor activity, rapid and durable responses, and an acceptable safety profile in patients with aCSCC. Cemiplimab Q4W may provide a less burdensome dosing regimen than the approved Q3W regimen.