Patient-Reported Outcomes Following the Switch from Originator to Biosimilar Adalimumab Maintenance Therapy in Paediatric IBD Patients: A Single-Center Prospective Cohort

Introduction Biosimilars have been increasingly used in paediatrics allowing a significant cost reduction related to biologic administration. Patient perspective is crucial for achieving therapeutic compliance. We aimed to assess patient experience following the switch from Adalimumab (ADA) originator to a biosimilar in a paediatric IBD (PIBD) cohort on maintenance therapy. Methods We prospectively enrolled PIBD patients on ADA maintenance therapy switched from originator to biosimilar (adalimumab-adaz), irrespectively of disease activity, in a single tertiary center (11/2023-06/2024). Patients' real-life experience with the switch was assessed through a study-specific survey administered 8-12 weeks post-switch. Results Overall, 13 patients (12 Crohn’s disease, 1 ulcerative colitis; 10 males) were included; median age at the switch was 16.7 years (IQR: 13.7-17.4). 8/13 (62%) reported increased apprehension about administering the drug post-switch, with 6/13 (46%) declaring a change in the administration modality. The majority of the cohort, 11/13 (85%), reported an increase in pain at the injection site (median NRS scale 5, IQR: 1-8), without a significant increase in local itchiness, erythema, or swelling. Overall, 6/13 patients (46%) expressed satisfaction with the switch, while 9/13 (69%) expressed a desire to modify aspects of the injection device. No severe drug-related adverse-events were noted. Conclusions Half of our PIBD cohort was satisfied with the switch with reported increased administration apprehension post-switch despite the preparatory training provided beforehand. For subcutaneous biosimilars, when considering a non-medical switch from the originator, it is fundamental to evaluate delivery devices to ensure long-term compliance, in addition to the safety, efficacy, and economic considerations.