Effectiveness and drug survival of adalimumab across clinical phenotypes of Behçet’s syndrome: an exploratory real-world cohort study

Objective To describe treatment response, drug retention, and exploratory phenotype-related patterns of response to adalimumab in a real-world cohort of patients with Behçet’s syndrome. Methods We conducted a single-center, single-arm retrospective cohort study including adult patients with Behçet’s syndrome treated with adalimumab at a tertiary referral center between 2004 and 2024. Disease activity was assessed using the Behçet’s Disease Current Activity Form (BDCAF). Clinical phenotypes were defined post hoc according to baseline organ involvement. All phenotype-based and predictor analyses were considered exploratory. Outcomes included treatment retention, changes in BDCAF score, clinical response rates, phenotype-specific response, safety, and exploratory predictors of primary non-response and treatment discontinuation. Results Ninety-two patients were included (66.3% female; mean disease duration 17.0 ± 6 years; mean follow-up duration after ADA initiation 36.7 ± 38.6 months). Among the 42 patients with complete paired BDCAF data available for response assessment, mean BDCAF decreased from 6.2 to 0.7 (p<0.001), and 34 patients (81.0%) achieved complete remission. Median drug retention was 41 months, with retention rates of 77.6% at 1 year, 51.7% at 3 years, and 41.4% at 5 years. Half of patients discontinued treatment over time, mainly due to secondary loss of efficacy. Response rates were numerically higher in the ocular-predominant phenotype (72.2%). Analyses of baseline features suggested a possible signal for anterior uveitis; however, these findings should be interpreted as hypothesis-generating. Adverse events occurred in 13.0% of patients, most commonly hypersensitivity and injection-site reactions. No serious adverse events were recorded. Conclusions Adalimumab was associated with reduced disease activity in this real-world cohort, although long-term persistence was limited. Differences across clinical phenotypes were descriptive and hypothesis-generating, with numerically higher response rates in ocular-predominant disease. These findings require confirmation in prospective multicenter studies using organ-specific outcome measures.