51342 Four-weekly dosing intervals with subcutaneous spesolimab appear to be required for optimal prevention of generalized pustular psoriasis flares: Data from the Effisayil 2 and Effisayil ON trials

Generalized pustular psoriasis (GPP) is a rare chronic skin disease characterized by recurrent, acute, and often life-threatening flares of widespread neutrophilic sterile pustules and systemic inflammation. Intravenous spesolimab, an anti-interleukin-36 receptor antibody, is approved for GPP flare treatment. In Effisayil 2, a randomized, placebo-controlled trial (NCT04399837), subcutaneous spesolimab was superior to placebo and well-tolerated for flare prevention when administered as a 600-mg subcutaneous loading dose followed by 300 mg every 4 weeks (q4w) over 48 weeks. In Effisayil 2, 3/30 (10.0%) patients receiving subcutaneous spesolimab 300 mg q4w had flares, and there were no flares after Week 4 until the end of the study. We assessed the effect on flare recurrence of a longer (q12w) interval between subcutaneous spesolimab doses in Effisayil 2 and Effisayil ON (NCT03886246), an ongoing open-label extension trial. Flares were defined as a ≥2-point increase in GPP Physician Global Assessment total score with pustulation subscore of ≥2, or intravenous spesolimab or standard of care treatment due to GPP worsening. In Effisayil 2, 9/31 (29.0%) patients who received subcutaneous spesolimab 300 mg q12w had a flare; of those, 7/9 (77.8%) experienced a flare before their second subcutaneous dose (Week 12), and 5/7 (71.4%) flares occurred during Weeks 4–12, indicating the need for q4w dosing. In Effisayil ON, 36/108 (33.3%) patients who started q12w dosing were either escalated to a q4w regimen (n=24) or experienced a flare (n=12). These observations suggest that subcutaneous spesolimab 300 mg q4w is the optimal dosing regimen for prevention of GPP flares.