Positive data from a phase 2 trial has been announced for Regeneron’s Libtayo (cemiplimab), an investigational regimen of a PD-1 inhibitor, as a neoadjuvant monotherapy for patients with stage two to four resectable cutaneous squamous cell carcinoma (CSCC).

As the second most common skin cancer in the UK, CSCC accounts for 23% of all non-melanoma skin cancers. For the majority of patients with CSCC, a good prognosis is possible if it is diagnosed and managed early. However, the cancer can be particularly difficult to treat when it progresses to advanced stages.

In the multicentre, phase 2 trial, 79 patients received up to four fixed doses of Libtayo every three weeks prior to surgery, with 62 patients receiving all four doses and 70 patients undergoing surgery.
The study demonstrated a 63.3% combined pathologic response rate, with 50.6% of patients achieving the primary endpoint of complete pathologic response, and 12.7% experiencing a major pathologic response by independent pathologic review. An objective response rate of 68% was achieved.

The treatment discontinuation rate due to adverse events was 1%, and there was one death due to worsening congestive heart failure considered related to treatment. Patient follow-up in the trial is ongoing to assess disease- free survival.