Avelumab Approved for Treating Metastatic Merkel Cell Carcinoma

It is a new era for patients living with metastatic Merkel cell carcinoma (MCC). The US Food and Drug Administration (FDA) has approved the first treatment for this rare, aggressive form of skin cancer.

The FDA on March 23, 2017, granted accelerated approval to avelumab (Bavencio) for the treatment of adults and pediatric patients 12 years and older with metastatic MCC, including those who have not received prior chemotherapy. Currently, fewer than half of metastatic MCC patients survive more than 1 year and fewer than 20% survive beyond 5 years. 

According to the National Cancer Institute, approximately 1,600 people in the United States are diagnosed with MCC every year. The majority of patients present with localized disease that can be resected. However, approximately half of all patients will experience recurrence and more than 30% will eventually develop metastatic disease.  

“The proportion of people who die from MCC is much higher than that of people with melanoma,” said Deborah Sarnoff, MD, President of the Skin Cancer Foundation and a Clinical Professor of Dermatology at New York University’s School of Medicine in New York. “With this approval, I believe there is new hope for people and their families touched by this rare form of skin cancer.”

Avelumab targets the PD-1/PD-L1 pathway and is designed to potentially engage both the adaptive and innate immune systems. It is theorized that this agent prevent tumors cells from using PD-L1 for protection against white blood cells. In vitro studies have shown it can induce antibody-dependent cell-mediated cytotoxicity.

The efficacy and safety of  this agent was demonstrated in the JAVELIN Merkel 200 trial, an open-label, single-arm, multicenter study conducted in 88 patients with histologically confirmed metastatic MCC whose disease had progressed on or after chemotherapy administered for distant metastatic disease. Among the 88 patients, 65% had one prior anticancer therapy for metastatic MCC and 35% had two or more prior therapies.

The study showed that 11% of patients experienced a complete response and 33% experienced complete or partial shrinkage of their tumors. The response lasted for more than 6 months in 86% of responding patients and more than 12 months in 45% of responding patients. The study showed that the duration of response ranged from 2.8 months to over 23.3 months. 

The most common adverse events of avelumab in this trial included fatigue (50%), musculoskeletal pain (32%), diarrhea (23%), nausea (22%), infusion-related reactions (22%), rash (22%), decreased appetite (20%), and peripheral edema (20%). The most common serious risks include pneumonitis, hepatitis, colitis, endocrinopathies, nephritis, and other immune-related reactions.

Avelumab is being investigated in 30 clinical programs, including nine phase III trials. Currently, researchers are evaluating it in more than 4,000 patients across more than 15 tumor types.