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Evidence-Based Oncology
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Cemiplimab significantly enhances disease-free survival in high-risk cSCC patients, reducing recurrence and metastasis risks, according to findings presented at ASCO.
Cemiplimab (Libtayo; Regeneron) significantly improved disease-free survival, reducing the risk of recurrence by 68% and distant metastases by 65% in patients with locally advanced cutaneous squamous cell carcinoma (cSCC), explained Danny Rischin, MD, medical oncologist and codirector, Division of Cancer Medicine, Peter MacCallum Cancer Centre in Melbourne, Australia, who spoke with The American Journal of Managed Care (AJMC).
Rischin was the lead author of the C-POST trial (NCT03969004), which had its findings presented at the 2025 American Society of Clinical Oncology Annual Meeting1 and simultaneously published in the New England Journal of Medicine.2
This transcript has been lightly edited.
Danny Rischin, MD | Image: Peter McCallum Cancer Centre
AJMC: Can you discuss the rationale for evaluating cemiplimab in patients with high-risk cSCC?
Rischin: Patients with [cSCC who] have locally advanced disease are at high risk of recurrence. There currently aren’t any adjuvant treatments of proven benefit. A significant proportion of those patients relapse, despite standard surgery and radiotherapy. We know from the metastatic setting or the more advanced setting [in which] the patients are not suitable for surgery that the PD-1–targeting therapy cemiplimab is very active, with responses in about half the patients, with durable responses, and it’s standard of care now in that setting. We wanted to see if we introduced it at this earlier stage of disease in patients who are at high risk of recurrence whether we could improve disease-free survival.
AJMC: Can you discuss the findings of the C-POST trial and
their implications?
Rischin: In the study, we found that the patients who received cemiplimab had a markedly improved disease-free survival, so lower risk of the cancer coming back, lower regionally or distantly, or dying of any cause. There was a 68% reduction in the risk of one of these events, and that benefit was seen both in a decrease in local regional recurrences, with an 80% reduction, and a 65% reduction in the risk of distant metastases. The treatment was generally well tolerated. The [adverse events] were pretty much as one would expect for an anti–PD-1 agent; there were no surprises there. The treatment, this trial unequivocally shows that use of the addition of adjuvant cemiplimab markedly improves disease-free survival. These are the results we were hoping to see. I wouldn’t say we were surprised, but it’s always very gratifying to see that the intervention you’ve proposed to improve outcomes for patients actually does that.
AJMC: What are the next steps of the study for moving into real-world practice?
Rischin: The trial is ongoing. This was the first analysis—and it’s obviously a highly significant result—but there’s ongoing follow-up particularly in terms of overall survival, so there’ll be more data to come. But as things stand, I think the results suggest that this is a treatment that represents a potential standard-of-care option that could be considered by physicians and their patients.
References
1. Rischin D, Porceddu SV, Day F, et al. Phase 3 trial of adjuvant cemiplimab (cemi) versus placebo (pbo) for high-risk cutaneous squamous cell carcinoma (CSCC). J Clin Oncol. 2025;43(suppl 16):6601. doi:10.1200/JCO.2025.43.16_suppl.6001
2. Rischin D, Porceddu S, Day F, et al; C-POST Trial Investigators. Adjuvant cemiplimab or placebo in high-risk cutaneous squamous-cell carcinoma. N Engl J Med. Published May 31, 2025. doi:10.1056/NEJMoa2502449
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