TYK2 Inhibition in Paradoxical Psoriasis
Paradoxical psoriasis is a side effect of a biological treatment (anti-tumor necrosis factor agent, short called anti-TNF) that is used to treat diseases of the skin, the intestine or the joints. If paradoxical psoriasis occurs, the anti-TNF-treatment often needs to be stopped and so far, no specific treatment for paradoxical psoriasis exists.

This research project aims to study whether the efficacy of the drug 'Deucravacitinib' 6mg, a tablet taken by mouth once a day is superior compared to taking a placebo in treating paradoxical psoriasis.
- EligibilityCriteria: Inclusion Criteria:  Clinical diagnosis of Paradoxical Psoriasis caused by anti-TNF treatment, with with Investigator Global Assessment ≥ 2 and Body Surface Area ≥ 2% Females who are of child-bearing potential should be practicing highly-effective contraception methods throughout the study and for 28 days after the last dose of study drug; Male subjects with a mechanical contraceptive method; be in good health be willing to have skin biopsies taken  Exclusion Criteria:  Use of any other anti-psoriatic therapy. Certain washout periods of treatments needs to be respected Infection(s) requiring treatment with intravenous (IV) anti-infectives within 30 days prior to the Baseline visit or oral anti-infectives within 14 days prior to the Baseline visit; A positive serology test for hepatitis B, hepatitis C, HIV; History of lymphoproliferative disease or of malignancy within the past 5 years. Chronic recurring bacterial infections or active tuberculosis; Positive pregnancy test at Screening and at the Baseline visit; Female subjects who are pregnant or breast-feeding or considering becoming pregnant during the study; History of clinically significant alcohol or drug abuse in the last 12 months Known hypersensitivity to Deucravacitinib or any of its excipients Current severe progressive or uncontrolled disease Live vaccine within 12 weeks before Baseline Visit. - HealthyVolunteers: No - Gender: All - MinimumAge: 18 Years - StdAgeList: Adult, Older Adult