Longer-Term Results of Pivotal Study in Advanced Cutaneous Squamous Cell Carcinoma

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New, longer-term data from a pivotal phase II trial in advanced cutaneous squamous cell carcinoma (CSCC), were presented during the ASCO20 Virtual Scientific Program and discussed during a poster discussion.1 Danny Rischin, MD, of the Peter MacCallum Cancer Centre, Victoria, Australia, presented the results from longer follow-up of the PD-1 inhibitor cemiplimab as monotherapy for patients with advanced CSCC in whom surgery or radiation is not possible.

Dr. Rischin is Director in the Department of Medical Oncology at the McCallum Cancer Center.

Danny Rischin, MD

Danny Rischin, MD

Based on earlier data from the open-label, single-arm, global, pivotal phase II trial of 193 patients with locally advanced CSCC or metastatic CSCC who were not candidates for curative surgery or curative radiation, along with results from a phase I study,  in September 2018 the U.S. Food and Drug Administration (FDA) approved cemiplimab (known as cemiplimab-rwlc in the United States) for the treatment of patients with advanced CSCC. Approval was based on the finding of durable objective responses in patients with advanced CSCC who received cemiplimab-rwlc at 3 mg/ kg intravenously every 2 weeks.2

Three-Year Follow-up

Historical data show median overall survival of approximately 15 months with conventional chemotherapy or EGFR inhibitors.3 With up to 3 years of follow-up, results from the pivotal phase II trial showed 46% of patients (95% confidence interval of 39% to 53%) experienced tumor shrinkage following cemiplimab treatment, with a median time to response of 2 months. Furthermore, more patients (16%) saw their tumors disappear completely over time compared to previous analyses. Among patients with metastatic disease who had the longest available follow-up, 20% of patients have now achieved a complete response, increasing from 7% in the 2017 primary analysis. Among patients who achieved a complete response in any group, median time to complete response was 11 months. Median overall survival and median duration of response have yet to be reached for any treatment group.

“The 3-year follow-up data demonstrate significant long-term outcomes with [cemiplimab], which is now standard-of-care for patients with advanced CSCC in many countries,” said Dr. Rischin. “The [cemiplimab] data on duration of response and overall survival provide new insights into the longer-term treatment of advanced CSCC, with the median still not reached for either measure. Remarkably, it is exciting to see the number of complete responses increase with longer follow-up, which reinforces the potential ongoing benefit of [cemiplimab] treatment in this aggressive skin cancer,” he said.

Across all groups combined, complete responses are now 16%; in the metastatic group with the longest follow-up, complete response rates are 20% representing a 200% increase over 2 years.

Safety and Quality of Life

No new safety signals were identified. The most common treatment-emergent adverse events were fatigue (35%), diarrhea (28%), and nausea (24%). The most common grade 3 or higher treatment-related adverse events were pneumonitis (3%), autoimmune hepatitis (2%), anemia, colitis, and diarrhea (each 1%). No new adverse events resulting in death were reported compared to previous reports.

“The [cemiplimab] data on duration of response and overall survival provide new insights into the longer-term treatment of advanced CSCC, with the median still not reached for either measure.”
— Danny Rischin, MD

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These results demonstrate both longer durability and higher complete response rates than previously reported. The data make up part of the largest and most mature prospective clinical dataset in patients with metastatic CSCC or locally advanced CSCC who are not candidates for curative surgery or radiation.

In addition to the updated efficacy and safety data, a separate post hoc analysis of health-related quality of life (HRQL) outcomes from the Phase II trial was presented for the first time. A large majority (83%) of patients reported improved or stable overall health-related quality of life (HRQOL) and 43% of patients experienced a clinically meaningful reduction in pain within 4 months of treatment. The analysis was based on patient responses to the European Platform of Cancer Research cancer specific 30-item HRQL questionnaire (QLQ-C30).

CSCC is the second most common type of skin cancer in the world, accounting for approximately 20% of all skin cancers, and the number of newly diagnosed cases is expected to rise substantially in many countries. Although CSCC has a good prognosis when caught early, the cancer can prove especially difficult to treat effectively when it is advanced, and patients can experience reduced quality of life due to the impact of the disease as it progresses. Approximately 7,000 patients in the United States die annually of advanced CSCC, which is comparable to the number of deaths caused by melanoma. 

Disclosure: Dr. Rischin has received research funding from Bristol-Myers. Squibb, Genentech/Roche, GlaxoSmithKline, Merck, and Regeneron. He has received travel and accommodations expenses from Merck. For disclosures of all study authors, visit


1. Rischin D, Khushalani NI, Schmults CD, et al: Phase II study of cemiplimab in patients with advanced cutaneous squamous cell carcinoma. Longer follow-up. ASCO20 Virtual Scientific Program. Abstract 10018.

2. Migden MR, Rischin D, Schmults CD, et al: PD-1 blockade with cemiplimab in advanced cutaneous squamous-cell carcinoma. N Engl J Med 379:341-351, 2018.

3. Cowey CL, Robert NJ, Davies K, et al: Treatment patterns and outcomes among patients with advanced cutaneous squamous cell carcinoma (CSCC) in a US community oncology setting. 2019 ASCO Annual Meeting. Abstract e21033.