Outcomes of children with juvenile idiopathic arthritis receiving biological disease-modifying anti-rheumatic drugs: a retrospective single-centre experience from India.

Background: We aimed to study the outcomes (remission, flare and adverse events) of biological disease-modifying anti-rheumatic drugs (bDMARD) in children with JIA from a low-middle-income country setting, and explore the factors associated with these outcomes. Methods: The Pediatric Rheumatology Clinic bDMARD register (2009 to August 2024) was screened to enrol children with JIA and at least 3 months follow-up whilst on bDMARDs. Participant characteristics and clinical responses were collected in a pre-designed proforma to evaluate the primary objective i.e., studying outcomes among children with JIA on bDMARDs. The secondary objective was to study factors associated with time-to-remission (TTR) and flare-after-stopping-bDMARDs. Findings: One-hundred-fifteen children (59.1% boys) with 168 patient-years of bDMARD use were enrolled for this single-centre study. Enthesitis-related arthritis was the commonest subtype of JIA (n = 44, 38.3%). The most commonly used bDMARD was adalimumab (n = 43, 37.3%). The median (IQR) delay to initiation of bDMARD from the perceived need was 2 (0-6) months, primarily due to financial impediments (n = 81, 70.4%). Fifteen (13%) children screened positive for tuberculosis infection. One hundred ten (95.6%) children achieved remission on bDMARD, after a median (IQR) of 7.5 (4-12) weeks. Macrophage activation syndrome at initiation was significantly associated (HR 3.6 (1.3-10.0), p = 0.03) with a longer time-to-remission. bDMARDs were stopped in n = 68/115 (59.1%) after a median (IQR) 15 (9.6-26.5) months, of whom n = 33/68 (48.5%) flared at 6 (3.5-12) months of follow-up. A longer time-to-remission (OR 1.12 (1.02-1.23), p = 0.01) was significantly associated with flare after stopping bDMARDs. Forty-two (36.5%) patients experienced adverse events. The most striking adverse events were serious infections requiring hospitalisation (n = 13, 11.3%) and tuberculosis (n = 4, 3.5%). All children who developed tuberculosis were on TNFi (Adalimumab). Interpretation: Though children on bDMARDs showed comparable remission rates, we noted a higher frequency of serious infections and tuberculosis, compared to the experience described from high-income countries. These observations highlight the need for further surveillance of outcomes of bDMARD use among children with JIA in an LMIC setting. Funding: There has been no financial support for this work.