Adalimumab Concentration Changes After Dose Escalation in Inflammatory Bowel Disease

Dose escalation of adalimumab (ADA) for loss or response in inflammatory bowel disease (IBD) is a common practice. Recent data suggest improved outcomes with an ADA concentration of 12 mcg/mL, but limited data are available on the ability to achieve a target concentration. The aim of this study was to determine the expected change in serum ADA concentration after a dose escalation performed every 7 days in patients with IBD.Methods:A retrospective cohort of patients with IBD receiving ADA was divided into every fourteen-day dosing, every 7-day dosing, and dose escalation (ie, q14 to q7 day dosing). The primary outcome was the change in ADA concentration. Multiple logistic regression was performed to identify predictors of achieving a target ADA concentration of ≥12 mcg/mL.Results:Overall, 380 patients were identified, of whom 200 underwent dose escalation, 100 remained on q14 days dosing, and 80 were maintained on q7 day dosing. After dose escalation, the mean ADA concentration increased by 5.5 mcg/mL (P < 0.0001). After dose escalation, a significant proportion of patients achieved an ADA concentration ≥12 mcg/mL (P = 0.0019), as well as clinical remission (P = 0.0053). Based on multiple logistic regression, age of <46 years [odds ratio (OR): 2.4; 95% confidence interval (CI): 1.3, 4.6; P < 0.01], body mass index of <29 (OR: 0.21; 95% CI: 0.1, 0.5; P < 0.0001), and initial ADA concentration of ≥3.0 mcg/mL were found to be associated with a target ADA concentration ≥12 mcg/mL (OR: 4.76; 95% CI: 2.3, 9.7; P < 0.0001).Conclusions:The average expected increase in serum ADA concentration after dose escalation from q14 to q7 days was 5.5 mcg/mL. The initial ADA concentration, age, and body mass index may influence the ability to achieve a target ADA concentration after dose escalation.