Toronto, Ontario, Canada, August 8, 2026
Regeneron Canada Company announced that Health Canada has approved Libtayo® (cemiplimab for injection) for the adjuvant treatment of adults with cutaneous squamous cell carcinoma (CSCC) at high risk of recurrence following surgery and radiation. The Notice of Compliance (NOC) expands the use of Libtayo in Canada and provides a new treatment option for patients facing a significant risk that their cancer will return after definitive local treatment. The approval is supported by results from the Phase 3 C-POST clinical trial, in which adjuvant cemiplimab produced a substantial reduction in the risk of disease recurrence or death compared with placebo. With Libtayo already used in several cancer indications, the new Canadian approval further strengthens the role of PD-1 immunotherapy in the management of high-risk skin cancer and highlights continued progress in adjuvant oncology treatment.
Libtayo Targets High-Risk Cutaneous Squamous Cell Carcinoma
Cutaneous squamous cell carcinoma is the second most common form of skin cancer and develops from squamous cells in the epidermis. Although many CSCC cases can be effectively treated, certain tumors are classified as high risk for recurrence because of factors including lymph node involvement, nerve or bone involvement, and recurrence at a previous surgical site. Patients with high-risk disease may therefore require additional treatment following surgery and postoperative radiation to reduce the likelihood of the cancer returning. Libtayo is a fully human monoclonal antibody targeting the PD-1 immune checkpoint receptor on T cells. By binding to PD-1, cemiplimab blocks a pathway that cancer cells can exploit to suppress T-cell activity, potentially allowing the immune system to recognize and attack tumor cells more effectively. The therapy was developed using Regeneron’s proprietary VelocImmune® technology, supporting the company’s broader strategy of developing antibody-based cancer medicines.
Phase 3 C-POST Trial Shows 68% Risk Reduction
The Canadian approval is based on findings from the international, randomized Phase 3 C-POST trial, which evaluated adjuvant cemiplimab against placebo in patients with high-risk CSCC following surgery and postoperative radiation. The study enrolled 415 patients, with 209 assigned to cemiplimab and 206 to placebo. After a median follow-up of 24 months, treatment with cemiplimab resulted in 24 disease recurrence or death events compared with 65 events in the placebo group. This translated into a 68% reduction in the risk of disease recurrence or death, with a hazard ratio of 0.32 and a 95% confidence interval of 0.20 to 0.51. The primary endpoint was disease-free survival, while secondary measures included freedom from locoregional recurrence, freedom from distant recurrence, and safety. The safety profile observed in the adjuvant setting was consistent with the established safety profile of Libtayo. The most common adverse events occurring in at least 15% of patients receiving cemiplimab included fatigue, diarrhea, pruritus, and rash. Permanent treatment discontinuation due to adverse events occurred in 9.8% of patients.
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Regeneron Strengthens Its Oncology Portfolio in Canada
The new approval expands Libtayo’s role in Canadian cancer care, where the medicine is also indicated for several advanced cancers, including metastatic or locally advanced CSCC, locally advanced basal cell carcinoma following treatment with a hedgehog pathway inhibitor, selected non-small cell lung cancer, and recurrent or metastatic cervical cancer. The additional adjuvant indication gives physicians another option for patients with high-risk CSCC after surgery and radiation, addressing an important need for preventing disease recurrence. For Regeneron, the decision reinforces its commitment to advancing immuno-oncology and developing therapies across multiple tumor types. The company’s oncology pipeline includes checkpoint inhibitors, bispecific antibodies, and other immune-based approaches, with Libtayo serving as an important foundation for investigational combinations. The Health Canada approval also demonstrates how positive randomized clinical evidence can support the expansion of established immunotherapies into earlier stages of cancer management, potentially helping patients maintain disease control following initial treatment.
Source: Regeneron press release
