Abstract
Adalimumab is an effective first line biologic therapy used to treat Children and Young People (CYP) with non-infectious uveitis and juvenile idiopathic arthritis (JIA). However, development of anti-Adalimumab antibodies (AAA) may compromise its efficacy. All CYP treated with Adalimumab between 2015-2023, managed within specialist paediatric rheumatology services at a single tertiary centre, were included in this retrospective study. Potential factors influencing AAA development and its implications for CYP were explored.
Data was collected from hospital systems including patient databases, clinical records and blood test result software.
390 CYP initiated Adalimumab treatment between 2015-2023. 112/390 (28.7%) were tested for AAA, with 156 individual tests performed. 51/112 (45.5%) CYP had positive AAA (>10mG/L), with an average detection time of 2.4 years (range:0.3-5.8yrs). 52.3% (11/21) CYP without concurrent disease-modifying anti-rheumatic drugs (DMARD) and 44.4% (24/54) CYP on sub-therapeutic dose (<15mg/m2) methotrexate had detectable AAA, compared to 21.1% (12/57) on full therapeutic dose (15-20mg/m2) methotrexate. Within-patient fluctuations in AAA levels (range: 13-522mG/L) were observed in 7 CYP despite no changes to regular medications (excluding use of corticosteroids).
Notable AAA incidence is described amongst our cohort of CYP receiving Adalimumab, with no significant difference found between non-infectious uveitis and JIA cohorts. Concurrent DMARD use at full therapeutic dosage alongside Adalimumab may reduce risk of developing AAA. Within-patient fluctuations in AAA levels question the clinical relevance of a positive antibody test. Decisions regarding Adalimumab discontinuation should be based on comprehensive clinical review rather than AAA levels alone. Future multi-centre collaboration is necessary to explore this further.