A Drug Receives FDA Approval for Merkel Cell Skin Cancer Treatment for the First Time

The FDA approved a drug for treating Merkel cell carcinoma, a rare and aggressive form of skin cancer, for the first time . On 23 March 2017, the FDA granted accelerated approval for metastatic Merkel cell carcinoma in adults and pediatric patients aged 12 and older, including those who had not previously received chemotherapy, to avelumab , an immunotherapy drug (trade name Bavencio®).

What Is Merkel Cell Skin Cancer?

Merkel cell cancer develops from skin cells called “Merkel” cells. Also known as Ranvier or tactile epithelial cells, Merkel cells are oval mechanoreceptors in the skin necessary for superficial touch sensation . Merkel cell cancer is a rare, biologically aggressive skin cancer mainly affecting older adults with fair skin and tending to recur locally and metastasize to regional lymph nodes. Other terms used for this tumor include neuroendocrine or primary small-cell carcinoma of the skin, trabecular cell carcinoma and anaplastic skin cancer. Rare tumors include this disease: United States statistics indicate approximately 166.000 people for every 1 case. It is more common in men, with a median age at diagnosis of 74 in men and 76 in women. Identified risk factors include intense exposure to the sun’s UV rays, fair skin, infections that suppress immunity, use of immunosuppressive medications and secondary cancers. %81 of Merkel cell carcinoma lesions are detected in sun-exposed areas.

Although surgery is attempted in most patients diagnosed with localized Merkel cell carcinoma, about half experience recurrence, and in more than %30 the cancer spreads to other body regions, causing metastatic disease.

Avelumab helps activate the immune system and attack cancer cells by blocking the interaction between PD-1 and PD-L1 proteins, one of the cellular mechanisms allowing cancer cells to hide from the immune system. It is an immunotherapy drug.

The Study

Avelumab approval is based on data from a single-arm study involving 88 patients with metastatic Merkel cell carcinoma who had received at least one previous chemotherapy regimen. Complete or partial response rates (overall response rate) were assessed through tumor shrinkage. The time tumors remained controlled in responders (response duration) was also examined. Of the 88 patients treated with avelumab, %33 had a complete or partial response. Response lasted in %86 of patients for longer than 6 months and in %45 for longer than 12 months.

Common avelumab side effects include fatigue, musculoskeletal pain, diarrhea, nausea, infusion-related reactions, rash, reduced appetite and swelling of the limbs (peripheral edema).

Recommended dose and administration: Every 14 days, a dose of 10 mg/kg given by intravenous infusion over 60 minutes.

Avelumab received FDA approval through accelerated approval, a pathway intended to meet medical needs in serious disease using clinical trial data expected to predict patient benefit. Further clinical research is required to confirm avelumab’s clinical benefit, and the drug sponsor continues these studies.