Long-term (≥3 year) efficacy and safety of subcutaneous spesolimab for treatment of generalized pustular psoriasis: results from the EFFISAYIL program

Introduction: Spesolimab is an anti-interleukin-36 monoclonal antibody approved for the treatment of generalized pustular psoriasis (GPP). We report long-term efficacy and safety data from patients with GPP receiving subcutaneous (SC) spesolimab treatment for ≥3 years since their first spesolimab dose in the EFFISAYIL program. The objectives were to (1) describe the efficacy and safety of long-term SC spesolimab treatment in patients with GPP, a chronic and potentially life-threatening inflammatory disease with a heterogenous clinical course requiring continuous disease control and (2) communicate long-term efficacy and safety data from the EFFISAYIL program in over 100 patients with GPP who have received SC spesolimab as continuous treatment for ≥3 years. Methods: EFFISAYIL ON (NCT03886246) is an ongoing open-label, multicenter, 5-year, long-term extension of the EFFISAYIL 1 (intravenous [IV] flare treatment) and EFFISAYIL 2 (SC treatment for flare prevention) trials. Flare events were defined as: meeting a protocol-defined threshold for GPP flare and/or IV spesolimab treatment and/or use of standard of care for GPP, per investigator discretion. Results: Overall, 159 patients have received at least one dose of SC spesolimab, considering all SC dosing regimens tested; most (n=118, 74.2%) have received long-term treatment (≥3 years). Of these, 74.6% (n=88) remained free of a flare event for ≥3 years and 25.4% (n=30) had at least one flare event. Long-term SC spesolimab treatment led to a reduction in the number of flares from 2.0 flares per year reported prior to entering the EFFISAYIL program to a cumulative mean of 0.13 per year (0.4 over the 3-year period). Safety data were consistent with the known safety profile of spesolimab. Conclusion: Preliminary results from this open-label study demonstrate that long-term (≥3 years) SC spesolimab treatment is effective in reducing the cumulative number of flares in patients with GPP. Additionally, the safety profile of spesolimab remains unchanged with long-term use.