An alliance of Germany’s Merck KGaA and US pharmaceuticals giant Pfizer has been granted US Food and Drug Administration (FDA) orphan drug status for its investigational cancer immunotherapy avelumab, recommended for treatment of Merkel cell carcinoma (MCC), a rare and aggressive type of skin cancer.

Avelumab is an investigational fully human monoclonal IgG1 antibody against programmed death-ligand 1 (anti-PD–L1). The two companies are currently conducting a Phase II study in Asia-Pacific, Australia, Europe and North America to assess its safety and efficacy in patients with metastatic MCC who have progressed after at least one prior chemotherapy regimen.

Altogether, Merck and Pfizer’s clinical trial program for avelumab now includes more than 1,000 patients treated across more than 15 tumor types, but the orphan drug status applies only to MCC.

The FDA’s orphan drug designation is granted to medications intended to treat rare diseases or disorders affecting fewer than 200,000 people in the US, or those that affect more than 200,000 people, but are unlikely to recover the costs of developing and marketing the drug.

Orphan drug status qualifies the sponsor for incentives provided for in the Orphan Drug Act. These can include protocol assistance for clinical trials, prescription drug user fee waivers, tax incentives and seven years of market exclusivity upon approval.

The designation does not alter the standard regulatory requirement to establish the safety and effectiveness of a drug through adequate and well-controlled studies to support approval.