Vanda Pharmaceuticals Inc. (NASDAQ: VNDA) announced that Japan's Ministry of Health, Labour and Welfare granted orphan drug designation to imsidolimab for treating generalized pustular psoriasis.

Imsidolimab is a humanized immunoglobulin G4 monoclonal antibody that inhibits interleukin-36 receptor signaling. The drug addresses deficiencies in endogenous IL-36 receptor antagonist regulation commonly observed in patients with the rare skin condition.

Approximately 2,200 people in Japan have been diagnosed with generalized pustular psoriasis, according to the Ministry of Health, Labour and Welfare. The condition is associated with IL36RN genetic variants that are more prevalent in the Japanese population, including in well-characterized founder families in Hokkaido.

The orphan drug designation provides development incentives including subsidies for research and development costs and potential market exclusivity for up to 10 years following approval. Japan's ministry grants this designation to medicines intended to treat rare diseases with significant unmet medical need.

This designation follows similar regulatory recognition in the United States. Generalized pustular psoriasis is described as a rare and severe inflammatory skin disease associated with systemic complications and increased mortality.

The announcement was based on a company press release.