This phase 2 clinical trial (EMPOWER-CSCC-1) evaluated cemiplimab (Libtayo), an anti-PD-1 checkpoint inhibitor, in patients with advanced and metastatic cutaneous squamous cell carcinoma. The study demonstrated significant objective response rates and durable responses in patients with locally advanced and metastatic cSCC who were not candidates for curative surgery or radiation. These results led to FDA approval of cemiplimab as the first systemic therapy approved for advanced cSCC, leading to its FDA approval as the first systemic therapy for advanced cSCC.

Cemiplimab achieved ~47% objective response rate in advanced/metastatic cSCC, with durable responses in the majority of responders.

This trial established cemiplimab as the first FDA-approved systemic therapy for advanced cSCC not amenable to curative surgery or radiation.

The high mutation burden of cSCC underlies its responsiveness to immune checkpoint inhibition, with implications for patient selection.