Serum Anti‐Drug Antibodies in Psoriasis Patients Undergoing Biologic Therapy in Real‐World Clinical Practice: A Single‐Center Retrospective Study

Biologics are essential for treating psoriasis; however, secondary failure, often due to the development of anti‐drug antibodies, is a significant concern. This study aimed to evaluate the relationship between secondary failure and the production of anti‐drug antibodies in a real‐world setting. Serum levels of anti‐adalimumab and anti‐secukinumab antibodies were measured using a commercial enzyme‐linked immunosorbent assay (ELISA) kit. A retrospective analysis was conducted on 85 patients with psoriasis, focusing on cases in which dermatologists identified secondary failure during biologic therapy. In the adalimumab group, eight patients were identified as having secondary failure. Among them, two showed high titers of anti‐drug antibodies, and one showed a low titer. In the secukinumab group, four cases were judged to have secondary failure, but none had elevated antibody titers. The results of this study indicate that the mechanisms underlying secondary failure in real‐world settings may vary depending on the drug. The secondary failure of adalimumab, a drug with high immunogenicity, is primarily attributed to the production of anti‐drug antibodies. In contrast, for secukinumab, which has low immunogenicity, extending the dosing interval may lead to reduced serum drug levels and an increased risk of secondary failure.