RecruitingPhase 2Drug trialA Study to Assess the Efficacy, Safety and Tolerability of DDY391 in Participants With Moderate to Severe Psoriatic ArthritisThe purpose of this Phase 2a/b study is: 1. to evaluate the efficacy, safety and tolerability of DDY391 in participants with psoriatic arthritis (PsA). 2. to determine the dose-response relationship of DDY391 in participants with PsA to support dose selection for Phase 3.