Study of Subcutaneous (Injected Under the Skin) Risankizumab to Assess Change in Disease Symptoms in Adult Participants With Moderate to Severe Plaque Psoriasis With Palmoplantar Involvement

Plaque Psoriasis is a chronic inflammatory disease in which skin cells build up and develop scaly red and white patches on the skin. It is caused by an overactive immune system where the body attacks healthy tissue by mistake. Palmoplantar (non-pustular) plaque psoriasis (PPPsO) represents a localized form of psoriasis in palms and soles. This study will evaluate how safe risankizumab is for the treatment of plaque psoriasis with palmoplantar involvement and to assess change in disease symptoms.

Risankizumab is an approved drug for the treatment of psoriasis. Study doctors put the participants in 1 of 2 groups, called treatment arms. Each group receives a different treatment. There is a 1 in 2 chance that participants will be assigned to placebo in Period A. In Period B, all the participants will receive risankizumab. Around 168 adult participants with a moderate to severe plaque psoriasis will be enrolled in approximately 55 sites across the world.

Participants will receive single subcutaneous (administered under the skin) risankizumab or placebo in period A (16 weeks). In period B (36 weeks), all participants will receive subcutaneous risankizumab once every 12 weeks.

There may be higher treatment burden for participants in this trial compared to their standard of care. Participants will attend regular visits during the study at a hospital or clinic. The effect of the treatment will be checked by medical assessments, blood tests, checking for side effects and completing questionnaires.