Give weekly adalimumab a chance before discontinuing it: a retrospective clinical and pharmacokinetic analysis in pediatric rheumatology

Background: Subcutaneous adalimumab is the preferred treatment for most children with juvenile idiopathic arthritis (JIA) and non-infectious uveitis, usually administered every other week. Some patients do not respond or lose responsiveness over time, leading to dose escalation to weekly administration. This study evaluated the efficacy and pharmacokinetics of weekly subcutaneous adalimumab in children with JIA and idiopathic uveitis. Methods: This is a retrospective study on clinical and pharmacokinetic characteristics of patients treated with subcutaneous adalimumab for psoriatic arthritis or non-infectious uveitis (idiopathic or JIA-associated) who did not respond or ceased to respond to biweekly administration. Results: Four patients were enrolled: three females and one male, with a median age of 15 years (range 7-18; IQR 6). One had juvenile psoriatic arthritis, two had idiopathic uveitis, and one had JIA-related uveitis. They all presented a poor control of the disease on biweekly administrations, while it was successfully controlled on weekly administrations. None of them presented adverse events. Pharmacokinetic analyses identified two groups of patients: those with high clearance and those with low clearance. In both groups, weekly dosing increased the predicted drug concentrations, and in patients with high clearance only weekly administration provided the predicted concentration exceeding the therapeutic cut-off of 9.6 mg/L. Conclusions: Weekly adalimumab administrations were safe and effective in controlling both articular and ocular inflammation. In cases where the disease is poorly controlled with regular biweekly administrations, we encourage escalating adalimumab treatment to weekly administration before adding other therapies or switching to different biologics.