Oral orismilast: Efficacy and safety in moderate‐to‐severe psoriasis and development of modified release tablets

Journal of the European Academy of Dermatology and Venereology
Open Access

Clinical Summary

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What was studied

A phase 2a randomized, double-blind, placebo-controlled trial tested oral orismilast immediate-release 30 mg twice daily for 16 weeks in adults with moderate-to-severe plaque psoriasis (n=36). A single-site phase 1 study in healthy adults compared modified-release (MR) vs immediate-release (IR) pharmacokinetics, food effects, and short-term safety (single-dose parts; multiple-dose MR up to 60 mg twice daily for 17 days vs placebo).

Key findings

At week 16, mean PASI was 7.1 with orismilast vs 13.1 with placebo (LS mean difference −6.0; p=0.005); PASI-75 occurred in 8/18 (44.4%) vs 1/18 (5.6%), PGA success 7/18 (38.9%) vs 1/17 (5.6%), and DLQI improved by −9.1 vs placebo (3.8 vs 12.9; p=0.008). GI adverse events were frequent with IR (16/18, 88.9%; nausea 11/18, 61.1%; diarrhoea 9/18, 50.0%), leading to withdrawals in 9/18 (50.0%); in phase 1, MR and IR had similar PK, and GI AEs were lower with MR vs IR after single 30 mg doses (16.7% vs 33.3%; nausea 0% vs 27.8%).

Study limitations

Small, single-centre phase 2a trial with high discontinuation (55.6% in orismilast IR; 50.0% in placebo) and LOCF imputation may bias efficacy estimates. Phase 1 findings were in healthy volunteers with small cohorts and included open-label parts; multiple-dose MR safety was short (17 days).

Clinical implications

Orismilast IR improved psoriasis signs but caused frequent GI AEs and high dropout; further development shifts to an MR tablet that kept similar exposure with fewer GI AEs after single dosing. Until larger patient trials with MR are complete, use remains investigational.