- Males and females aged ≥ 18 to < 80 years at screening who have a diagnosis of moderate-to-severe chronic plaque psoriasis (with or without psoriatic arthritis) for at least 6 months before the first administration of trial drug (a self-reported diagnosis confirmed by the Investigator is acceptable), and which has been stable per Investigator opinion for the last 2 months with no changes in morphology or significant flares at both screening and baseline (pre-treatment call):