Vanda Pharmaceuticals Inc.  announced the submission of a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) for imsidolimab, a novel IgG4 IL-36 receptor antagonist, to treat generalized pustular psoriasis (GPP). Imsidolimab inhibits IL-36 receptor signaling, addressing the deficiency in the endogenous IL-36RA regulator commonly seen in GPP patients due to IL36RN gene mutations.

The BLA is supported by positive results from the global Phase 3 GEMINI-1 and GEMINI-2 studies, where a single intravenous dose of imsidolimab led to rapid disease clearance, achieving clear or almost clear skin, with efficacy maintained throughout an approximately 2-year maintenance study period with monthly doses. Imsidolimab demonstrated a favorable safety profile with no clinically meaningful safety signals.

GPP is a rare, chronic, life-threatening autoinflammatory skin disorder characterized by sudden flares of widespread pustules, erythema, and systemic symptoms such as fever and fatigue. Driven primarily by loss-of-function mutations in IL36RN, GPP represents a significant unmet medical need, with prevalence estimates varying widely by region, ranging from approximately 2 to 124 cases per million worldwide (e.g., lower in Europe and higher in parts of Asia).

"The submission of the BLA for imsidolimab marks a critical milestone in our efforts to bring this innovative therapy to patients suffering from GPP," said Mihael H. Polymeropoulos, M.D., President, CEO and Chairman of the Board of Vanda Pharmaceuticals. "Imsidolimab builds on our growing expertise in rare orphan disorders and our anti-inflammatory portfolio, including Ponvory^®, which is approved for the treatment of relapsing forms of multiple sclerosis and is in clinical development for the treatment of psoriasis and ulcerative colitis. We look forward to potential FDA approval and leveraging our commercial infrastructure to address this debilitating condition."

Vanda has requested priority review for the BLA, citing GPP's status as a rare orphan disease with significant unmet need. If granted, priority review would establish a six-month review cycle, with a potential FDA approval of imsidolimab for the treatment of GPP as early as mid-2026.