A phase 2a randomized, double-blind, placebo-controlled, sequential dose-escalation study to evaluate the efficacy and safety of ASP015K, a novel Janus kinase inhibitor, in patients with moderate-to-severe psoriasis.

Background: Many immune-mediated disorders, including psoriasis, involve cytokine signalling via Janus kinase (JAK) enzymes. ASP015K (also designated JNJ-54781532), a novel oral JAK inhibitor, has shown moderate selectivity for JAK3 over JAK1 and JAK2 in enzyme assays.

Objectives: The objective of this study was to evaluate the efficacy and safety of escalating, sequentially grouped, doses of ASP015K vs.