Effisayil 1 is the first multinational, randomized, double-blind, placebo-controlled, phase II trial to show promising clinical outcomes of spesolimab, a humanized monoclonal antibody targeting the IL-36 receptor, in patients presenting with a GPP flare.

Effisayil 1 has a study design that evaluates the efficacy and safety of spesolimab more accurately; the study also includes more diverse populations and the largest sample size to date, as well as GPP-specific primary and key secondary endpoints.

The IL-36 family plays a dominant role in the pathogenesis of GPP.