The U.S. Food and Drug Administration granted accelerated approval to Bavencio (avelumab) for the treatment of adults and pediatric patients 12 years and older with metastatic Merkel cell carcinoma (MCC), including those who have not received prior chemotherapy. This is the first FDA–approved treatment for metastatic MCC, a rare, aggressive form of skin cancer.

According to the National Cancer Institute, approximately 1,600 people in the United States are diagnosed with MCC every year. While the majority of patients present with 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.

Bavencio targets the PD–1/PD–L1 pathway (proteins found on the body’s immune cells and some cancer cells). By blocking these interactions, Bavencio may help the body’s immune system attack cancer cells.

Bavencio received an Accelerated Approval, which 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.

The approval of Bavencio was based on data from a single–arm trial of 88 patients with metastatic MCC who had been previously treated with at least one prior chemotherapy regimen. 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 Bavencio 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.

Common side effects of Bavencio include fatigue, musculoskeletal pain, diarrhea, nausea, infusion–related reactions, rash, decreased appetite and swelling of the limbs (peripheral edema). The most common serious risks of Bavencio are immune–mediated, where the body’s immune system attacks healthy cells or organs, such as the lungs (pneumonitis), liver (hepatitis), colon (colitis), hormone–producing glands (endocrinopathies) and kidneys (nephritis). In addition, there is a risk of serious infusion–related reactions. Patients who experience severe or life–threatening infusion–related reactions should stop using Bavencio. Women who are pregnant or breastfeeding should not take Bavencio because it may cause harm to a developing fetus or a newborn baby.

The FDA granted this application Priority Review and Breakthrough Therapy designation. Bavencio also received Orphan Drug designation, which provides incentives to assist and encourage the development of drugs for rare diseases.