Efficacy and safety of risankizumab in Japanese patients with generalized pustular psoriasis or erythrodermic psoriasis: Primary analysis and 180‐week follow‐up results from the phase 3, multicenter IMMspire study

Risankizumab, a humanized immunoglobin G1 monoclonal antibody that specifically inhibits interleukin 23 by binding to its p19 subunit, is approved in Japan to treat numerous indications, including generalized pustular psoriasis (GPP) and erythrodermic psoriasis (EP). Both GPP and EP are severe forms of psoriasis that have limited treatment options. In IMMspire (A Study to Assess Efficacy and Safety of Two Different Dose Regimens of Risankizumab Administered Subcutaneously in Japanese Subjects With Generalized Pustular Psoriasis or Erythrodermic Psoriasis) (NCT03022045), a phase 3, randomized, multicenter study in Japan, we evaluated the efficacy and safety of risankizumab for Japanese adults with GPP or EP. Patients were randomized (1:1) to receive open‐label risankizumab 75 mg or 150 mg at weeks 0 and 4 and every 12 weeks thereafter through week 160. The primary efficacy end point was GPP or EP clinical response at week 16. Other efficacy end points included GPP or EP clinical response, ≥90% improvement from baseline in the Psoriasis Area and Severity Index (PASI 90) and Dermatology Life Quality Index of 0 or 1 (DLQI 0/1) through 180 weeks (last follow‐up visit). Safety was assessed throughout. A total of 17 patients (eight with GPP and nine with EP) were enrolled. All patients achieved the primary end point of GPP or EP clinical response at week 16. Among patients continuing risankizumab treatment, achievement of GPP or EP clinical response, PASI 90 and DLQI 0/1 were generally sustained throughout the treatment. The safety profile remained consistent with the safety profiles noted in previous risankizumab studies. Risankizumab demonstrated clinically meaningful efficacy at week 16, with durable efficacy and a favorable long‐term safety profile in Japanese patients with GPP or EP.