Psoriasis is an ancient, common, chronic immune-mediated skin disorder, but the 21st century has given rise to many effective novel therapies for the disease. Specifically, monoclonal antibodies have shown great efficacy at treating this skin disorder.
One monoclonal antibody that is FDA approved for the treatment of psoriasis is ustekinumab, which targets IL-12 and IL-23. The treatment is weight based with patients >100 kg receiving 90 mg and patients <100 kg receiving 45 mg. It is postulated that treatment failure in patients may be related to sub-therapeutic dosing of this medication.
Teresa Tsakok, M.D., and colleagues from the St John's Institute of Dermatology in London decided to further explore this hypothesis. The multicenter cohort studies BSTOP and BADBIR were utilized. In this study, clinical response to ustekinumab was assessed longitudinally using PASI scoring. During this study, in addition to PASI scoring, ustekinumab levels were also checked. The association between ustekinumab levels and PASI scored were performed.
The primary endpoint of the study was achieving a PASI 75. The secondary outcomes of study was a PASI 90, and a PASI of 1.5 or less. The association of drug levels and treatment response was calculated using logistic regression models. The cohort analyzed was composed of 491 subjects, which were mostly male.