US pharmaceutical company Vanda Pharmaceuticals Inc (Nasdaq:VNDA) announced on Thursday that the Committee for Orphan Medicinal Products at the European Medicines Agency (EMA) has adopted a positive opinion recommending orphan drug designation for imsidolimab, the company's investigational medicinal product, a high-affinity humanised immunoglobulin G4 (IgG4) monoclonal antibody, for the treatment of generalised pustular psoriasis (GPP).

The company said that this marks the first time the EMA has granted orphan drug designation recognition for a drug to treat GPP in the European Union. GPP is a severe, chronic, and potentially life-threatening inflammatory skin disease, genetically and clinically distinct from plaque psoriasis, driven by dysregulation in the interleukin-36 (IL-36) signalling pathway. It is characterised by widespread pustular eruptions, systemic inflammation, and serious complications that can lead to increased mortality.

According to Vanda, imsidolimab inhibits IL-36 receptor signalling, addressing the deficiency in the endogenous IL-36 receptor antagonist commonly observed in patients with GPP.

The EMA's orphan drug designation is granted to medicines intended for the treatment of life-threatening or chronically debilitating rare conditions affecting fewer than 5 in 10,000 people in the EU. Benefits include protocol assistance, reduced regulatory fees, and market exclusivity provisions in the EU following approval.

This designation follows similar regulatory recognitions in the United States and Japan. Additionally, the imsidolimab Biologics License Application (BLA) for GPP is currently under review by the FDA with a target action date of 12 December 2026.