Calliditas Therapeutics AB (Calliditas) (STO:CALTX), a specialty pharmaceutical company, announced on Tuesday the grant by the US Food and Drug Administration (FDA) of orphan drug designation (ODD) to the company for the treatment of Autoimmune hepatitis (AIH).

AIH is a chronic, autoimmune disease of the liver that occurs when the body's immune system attacks liver cells causing the liver to be inflamed. This disease may occur in any ethnic group and at any age but is most often diagnosed in patients between age 40 and 50. It is estimated that the patient population in the US amounts to approximately 50,000.

Calliditas plans to agree the regulatory pathway for this indication in consultation with the FDA later this year.

This FDA Orphan Drug Act (ODA) provides for granting special status to a drug or biological product to treat a rare disease that affect fewer than 200,000 people in the US. Orphan drug designation qualifies the sponsor of the drug for various development incentives of the ODA, including tax credits, protocol assistance and up to seven years of US marketing exclusivity from time of approval of a Biologics License Application (BLA).

Also, the company is currently running a global, pivotal phase 3 with study for the treatment of the rare disease IgA nephropathy, which has already obtained ODD by the FDA and the European Medicines Agency (EMA). Top line data for IgA nephropathy is expected in H2 2020.

Calliditas Therapeutics is focused on developing high quality pharmaceutical products for patients with a significant unmet medical need in niche indications, in which the company can partially or completely participate in the commercialisation efforts.