Drug helps patients avoid returning skin cancer
02 June 2025
A Peter Mac-led trial points to a way to improve treatment of a common and potentially deadly type of non-melanoma skin cancer, and which could help many to patients to avoid further treatment for recurrence of their cancer including disfiguring surgery.
The C-POST trial involved 415 patients with cutaneous squamous cell carcinoma (cSCC), a type of cancer which often occurs in sun-exposed areas of the head and neck and which is the leading cause of non-melanoma skin cancer deaths.
All patients in this Phase 3 trial also met criteria indicating “high risk” of their skin cancer returning after surgery to remove it and then radiotherapy to the site, which is the current standard of care.
Patients in this multi-centre clinical trial all received surgery and radiotherapy and were then randomised to take either the immunotherapy drug cemiplimab, or a placebo, for up to 48 weeks.
Benefits were seen across a range of measures and, notably, there was a marked reduction in the risk of the cancer returning - 30% in the placebo group versus just 9% in patients who received cemiplimab.
Disease-free survival was also greatly improved and, at two years, was 64% in the placebo group compared to 87% in the cemiplimab group.
“While surgery and radiotherapy remain the cornerstone of treatment for high risk cutaneous squamous cell carcinoma, there is a critical unmet need for systemic therapies to help prevent relapse and metastasis to ultimately drive better outcomes for patients,” says Professor Danny Rischin Research Lead, Head and Neck Cancer and Cutaneous SCC at Peter Mac and lead investigator of the trial.
“The Phase 3 C-POST trial demonstrates that cemiplimab is a highly active therapy in high-risk CSCC, with clinically meaningful outcomes across primary and secondary endpoints and exceptionally low rates of locoregional and distant recurrence.”
The trial results were presented at the 2025 ASCO (American Society for Clinical Oncology) Annual Meeting in Chicago over the weekend, and a corresponding paper was published in the New England Journal of Medicine.
Read the NEJM paper, titled “Adjuvant Cemiplimab or Placebo in High-Risk Cutaneous Squamous-Cell Carcinoma” here, or read the ASCO abstract here.
Australia has the world’s highest skin cancer rates, and two out of three Australians will be diagnosed with some form of skin cancer in their lifetime. Australian deaths from cSCC and other non-melanoma skin cancers have almost doubled in recent years.1
Cemiplimab, which works by blocking the PD-1/PD-L1 pathway which helps the immune system recognize and destroy cancer cells, is the current standard of care for treating advanced cSCC skin cancers which have already spread.
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Peter MacCallum Cancer Centre is a world leading cancer research, education and treatment centre and Australia’s only public health service dedicated to caring for people affected by cancer.
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