Adalimumab in Crohn's disease patients: pharmacokinetics in the first 6 months of treatment

Summary Background Adalimumab is an effective therapy for Crohn's disease patients. However, there is limited knowledge on the pharmacokinetic properties of adalilumab in patients with Crohn's disease. Aim To assess the pharmacokinetic properties of adalilumab in a retrospective clinical cohort of patients with Crohn's disease, naïve to anti‐tumour necrosis factor alpha therapy (anti‐TNF). Methods In a single tertiary centre, a clinical retrospective cohort was formed out of 76 patients with Crohn's disease who started adalilumab treatment (160/80/40EOW) between July 2007 and September 2010. We serially evaluated adalilumab serum levels at week 0, 12 and 28. Results Patients were followed for a median time of 201 days (range 120–244) and received a median of 14 adalilumab injections (range 6–25). Adalilumab levels, although divergent between patients, were stable between week 12 and week 28. There was no correlation between adalilumab level and time since last administration (r = −0.061). In a multivariable regression analysis of patient factors influencing week 28 adalilumab levels, the regression model containing CRP at week 28 and BMI at baseline weakly but significantly predicted week 28 adalilumab levels (R2 = 0.193, P = 0.004). Concomitant use of immunosuppressives was not a significant predictor (P = 0.304). Conclusions Intra‐individual adalilumab levels seem very stable during the first 28 weeks of treatment, whereas inter‐individual levels vary. Adalilumab levels appear stable over a 2‐week period, as the time since last adalilumab administration did not affect the adalilumab level. CRP and BMI weakly predict week 28 adalilumab levels, whereas the use of immunosuppressives does not.