Accelerated approval has been granted by the FDA for the checkpoint inhibitor avelumab (brand name Bavencio) for the treatment of patients with metastatic Merkel cell carcinoma (MCC), including those who have not received prior chemotherapy. Avelumab is the first FDA-approved treatment for metastatic MCC, the first disease that the drug has been approved to treat.
A rare and aggressive form of skin cancer, Merkel cell carcinoma, is 35 times less common than melanoma, but on average, it is about three times more likely to be deadly. Until now, there were no systemic therapies approved by the Food and Drug Administration for this cancer, and no approved therapies once the cancer had spread.
Avelumab is a human monoclonal antibody developed by Merck and Pfizer for use in immunotherapy. It targets the PD-1/PD-L1 pathway - proteins found on the body’s immune cells and some cancer cells. By blocking these interactions, avelumab may help the body’s immune system attack cancer cells.
Approximately 1,600 people in the United States are diagnosed with Merkel cell carcinoma every year, according to the National Cancer Institute. While the majority of patients experience localized tumors that can be treated with surgical resection, approximately half of all patients will experience recurrence, and more than 30 percent will eventually develop metastatic disease. In patients with metastatic MCC, the cancer has spread beyond the skin into other parts of the body.
The trial measured the percentage of patients who experienced complete or partial shrinkage of their tumors (overall response rate) and, for patients with a response, the length of time the tumor was controlled (duration of response). Of the 88 patients who received avelumab in the trial, 33 percent experienced complete or partial shrinkage of their tumors. The response lasted for more than six months in 86 percent of responding patients and more than 12 months in 45 percent of responding patients.
Richard Pazdur, M.D., acting director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research and director of the FDA’s Oncology Center of Excellence, said:
“While skin cancer is one of the most common cancers, patients with a rare form called Merkel cell cancer have not had an approved treatment option until now. The scientific community continues to make advances targeting the body’s immune system mechanisms for the treatment of various types of cancer. These advancements are leading to new therapies — even in rare forms of cancer where treatment options are limited or non-existent.”
An accelerated approval enables the FDA to approve drugs for serious conditions to fill an unmet medical need using clinical trial data that is thought to predict a clinical benefit to patients. Further clinical trials are required to confirm Bavencio’s clinical benefit and the sponsor is currently conducting these studies.
Kaufman, Howard L et al. Avelumab in patients with chemotherapy-refractory metastatic Merkel cell carcinoma: a multicentre, single-group, open-label, phase 2 trial The Lancet Oncology , Volume 17 , Issue 10 , 1374 - 1385