Comparative Efficacy of Adalimumab and Etanercept in Children with Juvenile Idiopathic Arthritis Under 4 Years of Age Depending on Active Uveitis

Abstract

Introduction: In 2011, Etanercept (ETA) was approved for clinical application in patients with Juvenile Idiopathic Arthritis (JIA) older than 2 years of age; Adalimumab (ADA) was approved in 2013. However, the available data for these patients are not sufficient even in large-scale registers. In older children, uveitis is a factor taken into consideration when choosing anti-TNF therapy, so we believe that its onset at an early age may affect the efficacy of treatment with different anti-TNF drugs. Objectives: This study aimed to evaluate the comparative efficacy of ADA and ETA in children of young age depending on their uveitis status. Methods: Comparative analysis involved patients who had initiated ETA (n=49, no active uveitis) or ADA (n=25; 13 patients with active uveitis and 12 patients without uveitis) therapy at an age of ≤4 years. Treatment efficacy was evaluated according to the dynamics of clinical signs and laboratory values, the ACRPedi and Wallace criteria. Results: ETA and ADA proved very efficacious in children under 4 years of age already after the first month of therapy according to the disease activity scores, laboratory values, and morning stiffness duration. After 3 months of therapy, the number of affected joints was substantially reduced in all three groups (p<0.01). The percentage of patients who had achieved ACR50/70/90 by the end of the follow-up period was 42/41/38 (85.7/83.7/77.6%) in ETA group, 10/10/9 (76.9/76.9/69.2%) in ADA group with uveitis, and 9/7/5 (75/58.3/41.7) in ADA group without uveitis, respectively. A comparable proportion of ETA patients and ADA patients with uveitis achieved remission (26 (53.1%) and 7 (53.8%), respectively), while only 3 (25%) of ADA patients without uveitis achieved long-term clinical remission (p-values are insignificant). Conclusion: In children younger than 4 years, ADA shows higher efficacy in patients with uveitis as compared to those without uveitis. Children without uveitis show a better response to ETA, although there is a risk of de novo uveitis. Therefore, ADA is the drug of choice for children with uveitis under 4 years of age, while ETA is preferred in children without uveitis.