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

BackgroundAdalimumab 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. AimTo assess the pharmacokinetic properties of adalilumab in a retrospective clinical cohort of patients with Crohn's disease, naive to anti-tumour necrosis factor alpha therapy (anti-TNF). MethodsIn 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. ResultsPatients were followed for a median time of 201days (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 (R-2=0.193, P=0.004). Concomitant use of immunosuppressives was not a significant predictor (P=0.304). ConclusionsIntra-individual adalilumab levels seem very stable during the first 28weeks 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.