Efficacy and safety of risankizumab in Japanese patients with moderate to severe plaque psoriasis: Results from the SustaIMM phase 2/3 trial

Risankizumab, a humanized immunoglobulin G1 monoclonal antibody, selectively inhibits interleukin‐23, a key cytokine in the pathogenesis of psoriasis, by binding to its p19 subunit. In SustaIMM (ClinicalTrials.gov/NCT03000075), a phase 2/3, double‐blinded, placebo‐controlled study, Japanese patients with moderate to severe plaque psoriasis (n = 171) were stratified by bodyweight and concomitant psoriatic arthritis and randomized 2:2:1:1 to 75 mg risankizumab, 150 mg risankizumab, placebo with cross‐over to 75 mg risankizumab and placebo with cross‐over to 150 mg risankizumab. Dosing was at weeks 0, 4, 16, 28 and 40, with placebo cross‐over to risankizumab at week 16. The primary end‐point was 90% or more improvement from baseline in Psoriasis Area and Severity Index (PASI‐90) at week 16 for risankizumab versus placebo. Missing data were imputed as non‐response. All primary and psoriasis‐related secondary end‐points were met for both risankizumab doses (P < 0.001). At week 16, PASI‐90 responses were significantly higher in patients receiving 75 mg (76%) or 150 mg (75%) risankizumab versus placebo (2%). Corresponding response rates were 86%, 93% and 10% for static Physician Global Assessment (sPGA) score of clear/almost clear; 90%, 95% and 9% for PASI‐75; and 22%, 33% and 0% for PASI‐100, with significantly higher responses for both risankizumab doses versus placebo. Through week 52, PASI and sPGA responses increased or were maintained and treatment‐emergent adverse events were comparable across treatment groups. Both doses of risankizumab were superior to placebo in treating patients with moderate to severe plaque psoriasis. The safety profile was consistent with previous risankizumab trials, with no new or unexpected safety findings.