Cemiplimab Improves Disease-Free Survival as Adjuvant Therapy in High-Risk Cutaneous Squamous Cell Carcinoma

Adjuvant cemiplimab (Libtayo; Regeneron), a PD-1 inhibitor that is standard of care for patients with advanced cutaneous squamous cell carcinoma (CSCC), demonstrated a clinically meaningful and statistically significant improvement in disease-free survival (DFS) in patients with high-risk CSCC after surgery, the primary end point of the C-POST trial (NCT03969004), according to a news release from Regeneron.^1,2

Cutaneous squamous cell carcinoma, light micrograph, photo under microscope | Image Credit: © Dr_Microbe | stock.adobe.com

The FDA previously granted cemiplimab approval for treatment in the SCC population based on positive clinical trial results that found the drug induced high, durable responses in patients, with a profile of adverse events (AEs) consistent with those reported in earlier studies. Cemiplimab was also approved in combination with platinum-based chemotherapy as a first-line treatment for patients with advanced non–small cell lung cancer (NSCLC), demonstrating its therapeutic versatility.^3,4

Now, new 24-month C-POST data released by Regeneron shows that cemiplimab is also effective in patients with high-risk CSCC in the adjuvant setting, with the drug demonstrating a 68% reduction in risk disease recurrence or death compared with placebo (HR: 0.32; 95% CI, 0.20-0.51, p < .0001). Regarding the rate of AEs, which was assessed in 205 patients receiving cemiplimab and 204 receiving a placebo, AEs occurred in 91% and 89% of patients, respectively.¹

“While surgery is curative for most people living with CSCC many are burdened with a higher risk of recurrence that can lead to death or disfiguration,” Danny Rischin, MD, MBBS, FRACP, lead investigator of the C-POST trial, said in the news release. “With no currently approved options in the adjuvant setting, these landmark results demonstrate cemiplimab could represent a major advance in delaying recurrence in these vulnerable patients.”¹

In C-POST, an ongoing, randomized, placebo-controlled, double-blind, phase 3 clinical trial, 415 patients with features linked with a high-risk of CSCC recurrence and who had previously completed surgery and post-operative radiation treatment were enrolled. Cemiplimab 350 mg or placebo was administered every 3 weeks for the first 12 weeks, followed by cemiplimab 700 mg or placebo every 6 weeks for 36 weeks.¹

C-POST will continue to gather additional follow-up data, including on the important secondary end point of overall survival. Other secondary end points include freedom from locoregional recurrence, freedom from distant recurrence, and the cumulative incidence of second primary CSCC tumors.¹

SCC is a common form of cancer in the US but can become difficult to treat in its more advanced forms, with “the potential…to cause substantial local destruction and disfigurement involving soft tissue cartilage and bone,” according to Heather Armbuster, PharmD, BCOP, during a Pharmacy Times Continuing Education Oncology Pharmacists Connect conference in 2023. For patients who cannot be cured with surgery or radiation, systemic therapies such as cemiplimab are an effective option, according to Armbuster.³

Pharmacists should remain aware of new indications granted to cemiplimab in the future as data is submitted to the FDA for regulatory approval. Identifying which patients stand to benefit the most from adjuvant therapy and managing AEs would become paramount pharmacist-led responsibilities.¹

“Cemiplimab [Libtayo] was the first PD-1 inhibitor approved for certain patients with advanced CSCC and has become a standard of care in this setting,” Israel Lowy, MD, PhD, clinical development unit head of oncology at Regeneron, said in the news release. “With these results, cemiplimab [Libtayo] now has the potential to also transform the treatment of high-risk resectable CSCC with adjuvant treatment.”¹

REFERENCES

1. Regeneron. Adjuvant Libtayo (cemiplimab) significantly improves disease-free survival (DFS) after surgery in high-risk cutaneous squamous cell carcinoma (CSCC) in phase 3 trial. News Release. Released January 13, 2025. Accessed January 14, 2025. https://investor.regeneron.com/news-releases/news-release-details/adjuvant-libtayor-cemiplimab-significantly-improves-disease-free

2. ClinicalTrials.gov. Study of adjuvant cemiplimab versus placebo after surgery and radiation therapy in patients with high risk cutaneous squamous cell carcinoma. National Library of Medicine. Last Updated September 19, 2024. Accessed January 14, 2025. https://clinicaltrials.gov/study/NCT03969004

3. Antrim A. FDA approves Libtayo, chemotherapy as first-line treatment for advanced non-small cell lung cancer. Pharmacy Times. Published November 9, 2022. Accessed January 14, 2025. https://www.pharmacytimes.com/view/fda-approves-libtayo-chemotherapy-as-first-line-treatment-for-advanced-non-small-cell-lung-cancer

4. Hippensteele A. Treatment of SCC with immune checkpoint inhibitors evolves. Pharmacy Practice in Focus: Oncology. 2023;5(6)(suppl). Published Online August 16, 2023. Accessed January 14, 2025. https://www.pharmacytimes.com/view/treatment-of-scc-with-immune-checkpoint-inhibitors-evolves