Data Sheet 1_Longitudinal monitoring of adalimumab levels and anti-adalimumab antibodies in Chinese patients with ankylosing spondylitis: a prospective cohort study.docx

Seven patients had pre-existing AAA, and 120 (90.2%) of the remaining 133 patients tested positive for AAA during follow-up. A total of 48 patients were excluded from the exposure–response relationship dataset owing to pre-existing AAA (n=7), lack of active disease (n=26), incomplete follow-up (n=8), and prolonged dosing intervals (n=7). Among the remaining 92 patients, a total of 58 (63%) achieved clinical response.

Adalimumab concentrations were higher, and AAA levels were significantly lower, in responders compared with non-responders at multiple time points. Exposure–response relationship models also revealed a steady-state adalimumab concentration target of 5.1 μg/mL and a week-4 concentration target of 3.3 μg/mL, corresponding to an 80% probability of clinical response. Thirty-six of 92 patients (39.1%) exhibited AAA-S/N values exceeding the putative clinically meaningful threshold (AAA-S/N=10).

Patients in the high-AAA group (AAA-S/N≥10) had lower drug levels (median: 1.5 μg/mL vs. 6.9 μg/mL, P<0.0001) and poorer response rates (38.8% vs. 78.6%, P = 0.0002), relative to those in the low-AAA group (AAA-S/N<10). Furthermore, patients who were week-4 AAA-positive exhibited a 1.8-fold increased risk of non-response (relative risk, 95% confidence interval, 1.1–2.8).</p>Conclusions<p>Our results demonstrate that longitudinal profiles of adalimumab concentrations and AAA levels show a strong association with clinical responses in this Chinese AS cohort, which may inform therapeutic drug monitoring–guided adalimumab treatment strategies that remain to be further validated.</p>Trial registration<p>ClinicalTrials.gov (NCT04875299).</p>