Successful Treatment of Pediatric Generalized Pustular Psoriasis (GPP) with Spesolimab: 5 Case Reports and Evaluations of Circulating IL-36 Levels

Background: Generalized pustular psoriasis (GPP) is a rare, severe, and potentially life-threatening inflammatory cutaneous disease. IL-36 is a key treatment target in GPP. Spesolimab, a humanized monoclonal antibody of the IL-36 receptor, has demonstrated a good efficacy and a favorable safety profile in adults with GPP. However, data on its use in children are scarce. Methods: We treated patients aged 4– 12 years with GPP with a single dose of spesolimab. The Generalized Pustular Psoriasis Physician Global Assessment (GPPGA) total score, GPPGA pustulation sub-score, Generalized Pustular Psoriasis Area and Severity Index (GPPASI), and the Japanese Dermatological Association severity index for GPP were evaluated. The levels of IL-36α, IL-36β, and IL-36γ were detected by the magnetic bead-based immunoassays, and the levels of IL-17A, IL-17C, IFN-γ, TNF, IL-6, and IL-8 were measured by the Olink proximity extension assay technology. Results: We included five patients (four boys and one girl) with a median age was 6.9 years old (range: 4.8 to 10.6 years), and a median age of onset of 1.7 years (range: 3 months– 10 years and 5 months). After 1 week of spesolimab administration, all patients had a total GPPGA score of 0/1 and pustulation subscore of 0, all patients had a GPPASI of 50, and four patients had a GPPASI of 75. Meanwhile, plasma levels of IL-36α, IL-36β, IL-36γ, IL-17A, IL-17C, IFN-γ, TNF, IL-6, IL-8 all decreased, and those of IL-36α, IL-36β, IL-17A, IL-17C, and IL-6 were statistically significant. There was no recurrence after 2 to 8 months of treatment. No other adverse event was recorded apart from one patient who experienced an upper respiratory infection in the first week. Conclusion: Spesolimab might be a prospective option for children aged 4 to 12 years. Keywords: generalized pustular psoriasis, pediatrics, spesolimab, IL-36R