Regeneron Pharmaceuticals has shared positive results from a late-stage trial of Libtayo (cemiplimab) in patients with high-risk cutaneous squamous cell carcinoma (CSCC) after surgery.
The phase 3 C-POST trial has been comparing adjuvant treatment with the PD-1 inhibitor against placebo in patients with features associated with a high-risk of CSCC recurrence and who have completed surgery and post-operative radiation therapy.
CSCC is the second most common type of skin cancer, with approximately 1.8 million cases diagnosed in the US every year.
Libtayo is designed to block cancer cells from using the PD-1 pathway to suppress T-cell activation and already holds approvals to treat certain patients with advanced CSCC.
C-POST met its primary endpoint of disease-free survival, with adjuvant Libtayo demonstrating a 68% reduction in the risk of disease recurrence or death in patients with high-risk CSCC after surgery compared to adjuvant placebo.
The trial will continue for additional follow-up, Regeneron said, adding that it is planning to file a submission with US Food and Drug Administration for Libtayo in this indication in the first half of 2025.
Israel Lowy, clinical development unit head, oncology, Regeneron, said: “Libtayo was the first PD-1 inhibitor approved for certain patients with advanced CSCC and has become a standard of care in this setting. With these results, Libtayo now has the potential to also transform the treatment of high-risk resectable CSCC with adjuvant treatment.”
Lead C-POST investigator, Danny Rischin, the Peter MacCallum Cancer Centre, added: “With no currently approved options in the adjuvant setting, these landmark results demonstrate Libtayo could represent a major advance in delaying recurrence in these vulnerable patients.”
Beyond CSCC, Libtayo is authorised to treat basal cell carcinoma, the most common type of skin cancer, as well as non-small cell lung cancer (NSCLC).
Regeneron recently presented five-years results from the phase 3 EMPOWER-Lung 1 trial of Libtayo as a first-line treatment for advanced NSCLC in adults with at least 50% PD-L1 expression and no EGFR, ALK or ROS1 aberrations.
According to the September announcement, a median overall survival of 26 months was seen in the Libtayo treatment group, compared to 13 months in the chemotherapy cohort, and median progression-free survival for Libtayo was eight months, compared to five months for chemotherapy.