Treatment Response of Patients with Erythrodermic Psoriasis after Switching to Guselkumab

INTRODUCTION: Erythrodermic psoriasis (EP) is a rare variant of psoriasis. Due to its rarity, evidence supporting its treatment is limited. Patients with erythrodermic psoriasis often respond less favorably to conventional treatment and have lower biologic drug survival compared with patients with plaque-type psoriasis. Guselkumab is an anti-interleukin-23 (IL-23) monoclonal antibody and has shown excellent and sustained treatment effect in moderate-to-severe plaque-type psoriasis. Until now, there is only one phase III open-label study reporting the effectiveness of guselkumab in this patient group. METHODS: Patients with chronic erythrodermic psoriasis who had been commenced on guselkumab were included in this retrospective study. All except one of our patients had plaque-type psoriasis prior to EP, and they met the criteria for EP before use of guselkumab. Due to inadequate response to previous treatment, including biologics, they were switched to guselkumab treatment. There was no washout period. They received guselkumab 100 mg at weeks 0 and 4, then every 8 weeks until at least week 28. Data were collected for patient demographics, Patient Area and Severity Index (PASI), and previous treatments. RESULTS: A total of 13 patients (12 male, 1 female) were included. The mean PASI improvement at weeks 4, 12, 20, and 28 was 37.5%, 60.9%, 67.5%, and 64.7%, respectively. The percentage of PASI 75 responders at weeks 4, 12, 20, and 28 was 15.4%, 38.5%, 53.9%, and 46.2%, respectively. At week 12, eight patients (61.5%) could achieve PASI 50 response. These PASI 50 responders at week 12 showed sustained and improved effectiveness during follow-up. CONCLUSION: Guselkumab is an effective biologic for treatment of moderate-to-severe plaque-type psoriasis, but the efficacy and drug survival are still compromised in EP patients. Our data describe the real-world experience of guselkumab treatment in this rare group of patients. Despite previous failure of other biologics, PASI response at week 12 is a good predictor of patient response and drug survival of guselkumab.