Vanda Pharmaceuticals has announced that the U.S. Food and Drug Administration (FDA) has accepted the filing of its Biologics License Application (BLA) for imsidolimab for the treatment of Generalised Pustular Psoriasis (GPP). The agency has assigned a target action date of December 12, 2026.

GPP is a rare, chronic and potentially life-threatening autoinflammatory skin disorder marked by sudden flares of widespread pustules, redness and systemic symptoms such as fever and fatigue. Advances in genetic research have linked the disease to dysregulation of the interleukin-36 (IL-36) pathway, often associated with mutations in the IL36RN gene.

Imsidolimab is a fully humanised IgG4 monoclonal antibody designed to inhibit IL-36 receptor signalling, targeting the underlying inflammatory pathway implicated in GPP. If approved, the therapy could address a significant unmet medical need and potentially offer advantages over existing treatment options.

The BLA submission is supported by data from global clinical trials conducted across multiple countries, including the United States and several European and Asian markets. In the pivotal GEMINI-1 and GEMINI-2 studies, a single intravenous dose of imsidolimab led to rapid disease clearance, with 53 percent of patients achieving clear or almost clear skin at Week 4 compared to 13 percent in the placebo group. Clinical benefits were maintained during an approximately two-year maintenance period with monthly dosing, and no disease flares were reported in the active treatment arm.

Imsidolimab demonstrated a favourable safety profile, with a low incidence of anti-drug antibodies, a potential differentiating factor compared to existing therapies. GPP prevalence varies globally, estimated at approximately 2 to 124 cases per million people, with higher rates reported in parts of Asia.

If approved, imsidolimab would mark Vanda’s third new drug approval within 12 months, following approvals for Nereus (tradipitant) and Bysanti (milsaperidone).

Vanda holds exclusive global rights to develop and commercialise imsidolimab under a licensing agreement with AnaptysBio. Regulatory and patent exclusivity for the therapy is expected to extend into the late 2030s.