Sanofi and Regeneron are gearing up to file their experimental PD-1 inhibitor cemiplimab on both sides of the Atlantic following the drug’s success in clinical trials.

The firms have unveiled new top-line data from the pivotal Phase II EMPOWER-CSCC 1 study, showing an overall response rate of 46.3 percent in patients with advanced cutaneous squamous cell carcinoma (CSCC), the second deadliest skin cancer after melanoma.

It was also noted that the median duration of response had not yet been reached at the data cut-off point (with 32 of 38 responses ongoing), and that the drug’s safety profile is showing itself to be consistent with anti-PD-1 agents already on the market.

“For patients with CSCC that cannot be cured by surgery or radiation, there are no FDA-approved treatment options, and advanced CSCC is responsible for 3,900 to 8,800 deaths per year in the US,” noted Israel Lowy, vice president of Global Clinical Development and head of Translational Science and Clinical Oncology, Regeneron.

"This is the largest prospective study ever conducted in this disease, and we are pleased that many people were able to achieve deep and durable responses with cemiplimab monotherapy. The high and durable response rates seen in this study are particularly notable given that the study enrolled patients regardless of biomarker status."

The data will form the basis of a rolling Biologics License Application (BLA) submission to the US Food and Drug Administration (FDA), which has been initiated and is expected to complete in the first quarter of 2018.

A submission to European regulators is also penciled in for the first quarter of next year.

Elias Zerhouni, president, Global R&D at Sanofi, said the firms would work with regulatory agencies around the globe to “bring this important therapy to advanced CSCC patients as quickly as possible.”