CLINICAL OUTCOMES OF ADALIMUMAB NONMEDICAL SWITCHES IN PEDIATRIC AND YOUNG ADULT PATIENTS WITH INFLAMMATORY BOWEL DISEASE

Abstract Objectives Biosimilars, including those for adalimumab, are well-established as safe and effective alternatives to their originator biologics, with robust evidence supporting their use in adult populations. Studies in adult patients with inflammatory bowel disease (IBD) have shown that switching from the adalimumab originator to a biosimilar results in comparable clinical outcomes. There is limited data evaluating outcomes of nonmedical switches in pediatric patients on adalimumab with IBD. This study aims to evaluate clinical outcomes of children and young adult patients with IBD who have undergone a nonmedical, insurance-driven switch from the adalimumab originator to a biosimilar. METHODS A single-center retrospective chart review was conducted among children and young adult patients with IBD who underwent a nonmedical switch from the adalimumab originator to a biosimilar from May 1, 2023 to July 30, 2024. Demographic data, physician global assessments (PGAs), laboratory results, and adalimumab levels and antibodies were collected prior to the switch and up to six months following the switch. Patients were assessed for continued biosimilar use at six months. Statistical analyses, including McNemar’s exact test, linear mixed effect models, and paired T tests, were completed to compare variables before and after the switch. RESULTS Fifty patients underwent a switch from the adalimumab originator to a biosimilar during the study period. Six months post-switch, 38 patients (76%) remained on the biosimilar. Among the 12 patients who were no longer on the biosimilar, three (6%) experienced disease worsening, three (6%) reported adverse reactions, and one (2%) had decreased drug level. Three patients (6%) had worsening disease before switching and two patients (4%) discontinued for unrelated switching reasons. Mean laboratory values for patients who remained on the biosimilar including albumin, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and hemoglobin (Hgb) were stable before and after the switch. Mean adalimumab levels decreased post-switch (from 18 to 15 ug/mL), which was statistically significant but not clinically relevant. Among the 42 patients with PGA scores recorded both before and after the switch, 36 patients (86%) demonstrated either stable or improved PGA scores post-switch. CONCLUSIONS Nonmedical, insurance-driven switches from the adalimumab originator to a biosimilar resulted in comparable clinical, laboratory, and pharmacologic outcomes in children and young adults with IBD. Most patients remained on the biosimilar at six months post-switch.