Unpacking the Data Behind Adjuvant Cemiplimab’s FDA Approval

In an interview with Targeted Oncology, Vishal A. Patel, MD, FAAD, FACMS, associate professor of Dermatology and of Medicine (Hematology/Oncology) at George Washington (GW) University School of Medicine and Health Sciences and director, Cutaneous Oncology Program at GW Cancer Center, summarizes the data of the pivotal phase 3 C-POST trial (NCT03969004) that ultimately led to the FDA’s recent approval of adjuvant cemiplimab (Libtayo) in patients with high-risk cutaneous squamous cell carcinoma (CSCC).

Watch part 1 and part 2 of Dr Patel’s interview.

Dr Patel describes the C-POST data as “consequential” and “unequivocally positive.” For the primary end point of disease-free survival (DFS), treatment with cemiplimab resulted in a 68% reduction in the risk of recurrence or death compared with placebo, equating to a hazard ratio (HR) of 0.32. The 24-month DFS rates for cemiplimab and placebo treatment were 87.1% and 64.1%, respectively. This effect was observed across all tumor subgroups evaluated, including nodal and non-nodal disease. Furthermore, the HR for locoregional control was 0.2, while the HR for distant control was 0.35.

Dr Patel considers these efficacy data as “large, practice-changing numbers,” making a comparison to previously approved adjuvant therapies for melanoma, which typically yielded HRs in the 0.4–0.6 range.

Regarding safety, cemiplimab’s adverse event (AE) profile was manageable and consistent with those established among PD-1 inhibitors, with no new signals or AEs identified. Treatment discontinuation due to an AE occurred in just under 10% of patients.

Altogether, these compelling figures supported the FDA’s decision to approve adjuvant cemiplimab in this indication, according to Dr Patel.

Read the full interview here.