Case Report: Telitacicept in the treatment of refractory juvenile idiopathic arthritis: clinical experience from three cases.

BACKGROUND: Refractory juvenile idiopathic arthritis (JIA) remains difficult to manage, particularly in patients with persistent disease activity despite multiple conventional synthetic disease-modifying antirheumatic drugs and biologic agents. Telitacicept is a dual inhibitor of B-cell activating factor and a proliferation-inducing ligand, but its use in JIA has not been well described. CASE PRESENTATION: We report three pediatric patients with refractory JIA treated with telitacicept. Case 1 was a 6-year-old girl with extended oligoarticular JIA who presented with recurrent swelling, pain, and limited motion of multiple joints, and elevated inflammatory markers after previous treatment with methotrexate, leflunomide, adalimumab, and intra-articular glucocorticoids. After switching to telitacicept combined with tofacitinib and methotrexate, joint symptoms and inflammatory markers improved, and an ACR70 response was achieved; clinical improvement was maintained during 12 months of follow-up. Case 2 was a 17-year-old boy with RF-positive polyarticular JIA and long-standing active disease involving the wrists and small joints of the hands. After telitacicept was added to background therapy, joint swelling resolved, inflammatory markers normalized, and ACR90 response was achieved during 9 months of follow-up. Case 3 was an 11-year-old boy with systemic JIA whose systemic manifestations had been controlled but who continued to have predominant polyarticular involvement. After telitacicept initiation, wrist swelling and inflammatory markers improved during the first 2 months, and an early ACR90 response was observed; however, relapse occurred at month 3 with recurrence of systemic symptoms, leading to discontinuation of telitacicept. No serious adverse events were observed. One patient developed a mild upper respiratory tract infection that resolved with symptomatic treatment. CONCLUSION: These cases provide preliminary clinical observations on telitacicept use in refractory JIA. BAFF/APRIL inhibition may warrant further investigation in selected patients with refractory JIA, particularly those with persistent articular involvement; however, prospective controlled studies are needed to evaluate efficacy and safety.