Antiadalimumab Antibodies in Patients With Inflammatory Ocular Diseases: Incidence and Clinical Outcomes.
PURPOSE: To determine the incidence, effect on adalimumab drug levels, and clinical consequences of antiadalimumab antibody formation, and to assess potential risk factors. DESIGN: Retrospective clinical cohort study. PARTICIPANTS: One hundred twenty-eight patients treated with adalimumab who underwent antiadalimumab antibody monitoring. METHODS: Beginning October 2023, regularly scheduled antiadalimumab antibody and adalimumab level testing was begun. Using staggered entry analysis, anchored observation to treatment initiation, incidence was calculated. Time-updated models evaluated risk factors for antiadalimumab antibody formation. MAIN OUTCOME: Incidence of antiadalimumab antibodies. RESULTS: Antiadalimumab antibodies developed in 37 of 128 patients for a rate of 0.077 per person-year (PY) (95% confidence interval [CI] 0.055/PY, 0.104/PY). Median serum adalimumab concentrations were significantly lower in antiadalimumab antibody-positive blood samples (2.6 µg/mL; interquartile range 0.8, 7.0) than in antibody-negative samples (10.2 µg/mL; interquartile range 6.9, 15.1), P < .00001. In time-updated analyses, there was a suggestion that concomitant immunosuppression was associated with a reduced risk of antiadalimumab antibodies (odds ratio [OR] 0.64; 95% CI 0.37, 1.10; P = .10) and weekly adalimumab dosing was associated with a reduced risk (OR 0.62; 95% CI 0.42, 0.91; P = .01). Antiadalimumab antibodies were associated with active ocular inflammation (OR 3.68; 95% CI 1.99, 6.82; P < .00001). CONCLUSIONS: Antiadalimumab antibodies occur commonly among patients treated with long-term adalimumab, with a cumulative incidence of nearly 50% by 8 years of therapy. Antibody formation was associated with lower serum adalimumab levels and active ocular inflammation.