Psoriasis is a chronic immune disease of the skin and joints that affects about 2% of the population. The most common form of psoriasis is plaque psoriasis, also called psoriasis vulgaris. A variety of drugs, including biologics, are available for treatment of moderate to severe psoriasis. When biologic agents are stopped, psoriasis can return (relapse) and often requires the biologic to be restarted and continued. No treatment program has been identified to prevent relapse of psoriasis.~The study design has a lead-in period of weight-based ustekinumab treatment, with all participants receiving either 45 mg ustekinumab (<= 100 kg) or 90 mg ustekinumab (> 100 kg) administered subcutaneously at weeks 0 and 4. At week 12, participants will be assessed for a Psoriasis Area and Severity Index (PASI) 75 response to ustekinumab. Participants who do not achieve a PASI 75 score will be discontinued from the investigation and permitted to seek standard therapy.
The purpose of this study is to determine if the use of ustekinumab, followed by abatacept, will prevent relapse in people with moderate to severe plaque psoriasis.