Regeneron has announced positive data from a phase 2 trial for an investigational regimen of PD-1 inhibitor Libtayo (cemiplimab) as a neoadjuvant monotherapy in 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 confirmatory, multicentre, single-arm phase 2 trial, 79 patients received up to four fixed doses of Libtayo every three weeks prior to surgery, with 62 receiving all four doses and 70 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. Moreover, 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. No new Libtayo safety signals were observed.
Patient follow-up in the trial is ongoing to assess disease-free survival, the company outlined, and a separate global phase 3 trial investigating Libtayo in the CSCC setting for patients at heightened risk for recurrence is enrolling patients.
The potential use of Libtayo as a neoadjuvant monotherapy in stage two to four resectable CSCC is investigational, and its safety and efficacy has not been evaluated by any regulatory authority for this indication.
However, the treatment has been approved by the US Food and Drug Administration (FDA) for three other indications: advanced CSCC that has spread or cannot be cured by surgery or radiation, locally advanced or metastatic basel cell carcinoma (BCC), and locally advanced non-small cell lung cancer (NSCLC).
Israel Lowy, senior vice president, translational and clinical sciences, oncology at Regeneron, said: “In the neoadjuvant trial in stage two to four CSCC presented at the European Society for Medical Oncology and published in the New England Journal of Medicine, Libtayo demonstrated greater than 60% response rates per both pathologic and imaging measures.
“Libtayo may therefore have expanded utility in earlier stages of cutaneous squamous cell carcinoma as a monotherapy to potentially help avoid surgery, and as part of a combination approach with surgery to facilitate function-preserving resections and minimise disfigurement.”