Guselkumab, a human interleukin‐23 monoclonal antibody in Japanese patients with generalized pustular psoriasis and erythrodermic psoriasis: Efficacy and safety analyses of a 52‐week, phase 3, multicenter, open‐label study

Generalized pustular psoriasis (GPP) and erythrodermic psoriasis (EP) are the rare and severe subtypes of psoriasis, which are often difficult to treat. The aim of this phase 3, open‐label study was to evaluate efficacy and safety of guselkumab, a human interleukin‐23 monoclonal antibody, in Japanese patients with GPP and EP. Guselkumab 50 mg was administrated to GPP (n = 10) and EP (n = 11) patients at weeks 0, 4 and thereafter every 8 weeks (q8w). Beginning at week 20, patients were escalated to 100 mg q8w if they met the dose escalation criteria. The primary end‐point was the proportion of patients achieving treatment success (Clinical Global Impression score of “very much improved”, “much improved” or “minimally improved”) at week 16. Safety evaluations included assessment of treatment‐emergent adverse events (TEAE) through week 52. At week 16, the proportions of GPP and EP patients achieving treatment success were 77.8% (7/9) and 90.9% (10/11), respectively. Furthermore, guselkumab treatment consistently showed improvement in responses of secondary end‐points such as Psoriasis Area and Severity Index, Investigator's Global Assessment, Japanese Dermatological Association severity index and improvement in body surface area involvement. Improvements in quality of life, as assessed by the Dermatology Life Quality Index, were also observed through week 52. The most commonly reported TEAE was nasopharyngitis (28.6%, 6/21). Safety findings were consistent with those observed previously in other studies. In conclusion, guselkumab treatment demonstrated efficacy and showed no safety concerns in Japanese patients with GPP and EP through week 52.