THE FOOD AND DRUG ADMINISTRATION (FDA) approved the immunotherapy Libtayo (cemiplimab) for high-risk cutaneous squamous-cell carcinoma (CSCC), a common skin cancer type. The Oct. 8, 2025, approval was based on findings that people given Libtayo after surgery and radiation lived longer without their disease recurring—a measure known as disease-free survival—compared with those treated with surgery and radiation alone. In the past, PD‑1 inhibitors like Libtayo and others have been used in metastatic CSCC and other instances when surgery isn’t possible, but this is the first approval for preventing recurrence in high‑risk patients after surgery and radiation.

The study, published May 31, 2025, in the New England Journal of Medicine, included 415 people with CSCC, who received either Libtayo or placebo for 48 weeks after undergoing surgery and radiation. Libtayo is an immune checkpoint inhibitor. It primes the body’s immune system to fight cancer by binding to a protein called PD-1 on immune system T-cells, helping T-cells attack cancer cells to slow or prevent tumor growth.

Although surgery is able to remove cancer in 95% of patients, some features found at the time of surgery, such as larger tumor size, cancer cells found in lymph nodes, and cancer infiltrating into bones or major nerves, suggest a higher risk of the cancer returning.

Patients received treatment over 48 weeks, starting an infusion of Libtayo or placebo every three weeks for first 12 weeks, followed by infusions every six weeks for an additional 36 weeks. People whose cancer progressed while taking placebo were able to receive Libtayo through the trial. The estimated disease-free survival at two years was 87.1% for people given Libtayo versus 64.1% for those in the group that received placebo.

“The results translate to a 68% reduction in the risk of disease recurrence or death compared to placebo,” says David Carr, a co-author of the study and a dermatologist at Ohio State University Wexner Medical Center. “This is a new paradigm for treating high-risk patients with cutaneous squamous-cell carcinoma.”

Squamous cell carcinoma is the second most common form of skin cancer, with an estimated 1.8 million people diagnosed in the U.S. each year. Caused by prolonged ultraviolet radiation from sun or tanning bed exposure, CSCC typically arises on the head and neck. It can often be treated with surgery alone, Carr says. People with high-risk squamous cell carcinoma who aren’t cured with surgery may require radiation. In a small subset of these patients, the disease recurs despite surgery and radiation. In the U.S., 1% to 2% of people with CSCC die yearly.

“Cutaneous squamous-cell carcinoma is a disease that has been overlooked by pharmaceutical companies and by medicine,” says Neil D. Gross, a surgeon-scientist at the University of Texas MD Anderson Cancer Center in Houston, who was not involved in the study. “For decades, we haven’t had anything to offer these patients [with high-risk disease] beyond surgery and radiation. This is an exciting new option for patients.”

Now, people with CSCC with high-risk features can receive Libtayo after chemotherapy and radiation to reduce their chance of recurrence. Researchers are also investigating whether taking Libtayo before surgery and radiation could improve patient outcomes.

People may discuss their individual risk and their overall health with their doctor to decide whether to take Libtayo immediately after surgery and radiation or wait to see if their cancer recurs before choosing the immunotherapy infusions, Gross says. Side effects of Libtayo can include fatigue, rash, diarrhea, itching, joint pain, hypothyroidism, and Bowen’s disease, which can cause red, scaly patches on the skin. Mild side effects can often be managed with medication, Gross says. “For decades, surgery followed by radiation has been the standard of care for patients with high-risk cutaneous squamous cell carcinoma. It’s great to be able to offer something else for these patients. Libtayo is a new standard of care.”

Sandra Gordon is a medical writer in Stamford, Connecticut.