US regulators have awarded breakthrough status to an experimental therapy being developed by Pfizer and Merck KGaA for a rare and aggressive form of skin cancer.

The fully human anti-PD-L1 IgG1 monoclonal antibody avelumab could offer patients with the metastatic Merkel cell carcinoma (MCC) the first specific treatment for their disease, which is currently treated with surgery, chemotherapy or radiotherapy.

Breakthrough Therapy designation is designed to speed up the development and review of medicines that targeting serious conditions, when preliminary clinical evidence indicates that the therapy may demonstrate a substantial improvement over

existing approaches.

In this case, the designation was awarded on the back of data from the global Phase II study, JAVELIN Merkel 200, which is assessing the safety and efficacy of avelumab in patients with metastatic MCC who have progressed after at least one previous chemotherapy regimen. Findings are due to be presented at a scientific congress next year, the firms noted.

The drug, which is thought to potentially enable the activation of T-cells and the adaptive immune system to induce cell-mediated cytotoxicity, has also picked up Orphan Drug designation and Fast Track designation in recent months.

MCC is a disease in which cancer cells form in the top layer of the skin, close to nerve endings, and is also known as neuroendocrine carcinoma of the skin or trabecular cancer. Around 1,500 new cases are diagnosed in the US every year.