The European Commission has granted orphan designation to imsidolimab (Vanda Pharmaceuticals) for the treatment of generalized pustular psoriasis (GPP), following a positive opinion from the European Medicines Agency's (EMA) Committee for Orphan Medicinal Products (COMP).2
According to Vanda, this marks the first time the European Commission has granted orphan designation to a drug for the treatment of GPP. The investigational therapy has previously received orphan drug designation for GPP from the US Food and Drug Administration (FDA) and Japan's Ministry of Health, Labour and Welfare.2
Imsidolimab is a fully humanized IgG4 monoclonal antibody that inhibits interleukin-36 (IL-36) receptor signaling. Dysregulation of the IL-36 pathway is an important driver of GPP, a rare, severe inflammatory skin disease characterized by widespread sterile pustules and systemic inflammation.
European Designation Expands Imsidolimab's Regulatory Progress
In the European Union, orphan designation is available for therapies intended to diagnose, prevent, or treat life-threatening or chronically debilitating rare diseases. Among other requirements, the condition must affect no more than 5 in 10,000 individuals in the EU.
Orphan designation can provide developers with incentives including protocol assistance, reduced regulatory fees, and market exclusivity following approval. Importantly, orphan designation does not constitute marketing authorization for imsidolimab.2
The European decision adds to regulatory progress for the therapy in the US and Japan. Vanda's biologics license application (BLA) for imsidolimab in GPP is currently under FDA review, with a target action date of December 12, 2026.2
"The European Commission's Orphan Designation for imsidolimab represents an important milestone for the GPP community and for our efforts to bring this investigational therapy to patients in Europe," said Mihael H. Polymeropoulos, MD, president, Chief Executive Officer, and chairman of the board of Vanda Pharmaceuticals.2
"With orphan designations now received in Europe, the United States and Japan, we remain focused on advancing imsidolimab for patients in these markets who need new treatment options," he added.2
imsidolimab represents an important milestone for the GPP community — Mihael H. Polymeropoulos, MD, president, Chief Executive Officer, and chairman of the board of Vanda Pharmaceuticals.
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Frequently Asked Questions
Imsidolimab is an investigational, fully humanized IgG4 monoclonal antibody designed to inhibit IL-36 receptor signaling. It is being developed for the treatment of GPP.
What does the European orphan designation mean?
The designation recognizes imsidolimab as a therapy being developed for a qualifying rare disease and can provide regulatory incentives including protocol assistance, reduced fees, and potential market exclusivity following approval. It does not mean imsidolimab has been approved for use in the EU.
Has imsidolimab been approved for GPP?
No. Imsidolimab remains investigational. Its BLA for GPP is currently under FDA review, with a target action date of December 12, 2026.
Where else does imsidolimab have orphan drug designation?
In addition to the European Commission designation, imsidolimab has received orphan drug designation for GPP in the US and Japan.
Phase 3 Evidence Supports Imsidolimab Development
Clinical evidence supporting imsidolimab's development in GPP includes the phase 3 GEMINI program. Results were published in NEJM Evidence in April 2026 and are included in the BLA currently under FDA review.1
The phase 3 program evaluated imsidolimab in adults with GPP, including a randomized, double-blind, placebo-controlled trial assessing the therapy during GPP flares. Imsidolimab targets the IL-36 receptor, thereby inhibiting signaling through a pathway implicated in the inflammatory activity underlying GPP.1
Vanda's August 24 announcement did not report additional efficacy or safety findings associated with the European designation. Instead, the designation represents another regulatory milestone as the company advances the therapy across multiple markets.2
Vanda holds an exclusive global license for the development and commercialization of imsidolimab. The company stated that regulatory and patent exclusivity associated with the therapy is expected to extend into the late 2030s.2
References
- Smieszek S, Przychodzen B, Tyner C, et al. Efficacy and safety of imsidolimab for generalized pustular psoriasis. NEJM Evid. 2026;5(5). doi:10.1056/EVIDoa2500272.
- Vanda Pharmaceuticals granted orphan designation for imsidolimab for the treatment of generalized pustular psoriasis by the European Commission. News release. Vanda Pharmaceuticals Inc. August 24, 2026. Accessed August 24, 2026. https://www.prnewswire.com/news-releases/vanda-pharmaceuticals-granted-orphan-designation-for-imsidolimab-for-the-treatment-of-generalized-pustular-psoriasis-by-the-european-commission-302857847.html
