LEO Pharma Announces New Long-Term Data for SPEVIGO® (Spesolimab-Sbzo) Injection in Adults with Generalized Pustular Psoriasis at AAD 2026

Key Takeaways

• 74.6% of patients had zero flares over three years.
• Flare rate dropped from 2.0 to 0.13 per year.
• IV SPEVIGO cleared pustulation in 50% by week one.
• Serious adverse events occurred in 36.6% of IV-treated patients.
• SPEVIGO is first IL‑36 targeted therapy for GPP.

Summary

LEO Pharma presented long‑term results from the five‑year EFFISAYIL ON extension, showing subcutaneous SPEVIGO® reduced generalized pustular psoriasis (GPP) flares from an average of two per year to 0.13, with 74.6% of patients experiencing no flares over three years. Intravenous SPEVIGO provided rapid rescue, achieving a pustulation subscore of zero in half of flare treatments by week one. Safety remained consistent, though serious adverse events were reported in 36.6% of IV‑treated patients. The data were unveiled at the 2026 American Academy of Dermatology meeting.

Pulse Analysis

Generalized pustular psoriasis (GPP) remains one of dermatology’s most challenging conditions, marked by sudden, life‑threatening flares and a mortality rate that can exceed 10%. The disease is driven by dysregulation of the IL‑36 pathway, making it a prime target for biologic intervention. SPEVIGO®, a humanized antibody that blocks the IL‑36 receptor, is the first therapy to directly address this mechanism, offering a biologically rational approach that differentiates it from broader immunosuppressants used in plaque psoriasis.

The EFFISAYIL ON extension provides the most comprehensive efficacy dataset for SPEVIGO to date. Patients on subcutaneous dosing experienced a dramatic decline in flare frequency—from two annual episodes pre‑treatment to just 0.13, and nearly three‑quarters remained flare‑free for three years. This sustained control is complemented by an intravenous rescue protocol that achieved clear pustulation scores in 50% of acute episodes within one week, underscoring the drug’s flexibility for both maintenance and rapid intervention. Clinicians now have evidence that long‑term IL‑36 inhibition can transform GPP from an episodic crisis into a manageable chronic condition.

From a market perspective, these results solidify LEO Pharma’s leadership in the niche GPP space and set a high bar for competitors. While serious adverse events were noted in the IV cohort, the overall safety profile aligns with earlier trials, mitigating major regulatory concerns. The data also open avenues for broader applications of IL‑36 blockade in other autoinflammatory disorders, positioning SPEVIGO as a platform therapy. As insurers and providers recognize the cost‑saving potential of reduced hospitalizations and flare‑related complications, adoption is likely to accelerate, driving revenue growth for LEO Pharma and expanding therapeutic options for patients who previously had limited choices.