Patients with rheumatoid arthritis (RA) who are treated with adalimumab and achieve high serum concentrations can increase their dosing interval to once every 3 weeks without experiencing an increase in disease activity, according to an open-label, non-inferiority study published in the Annals of the Rheumatic Diseases.
In order to reduce drug costs and possibly the risk for adverse events with adalimumab therapy in patients with RA, researchers in The Netherlands investigated whether the dosing interval could be prolonged by 50% in patients who have an adalimumab trough concentration of at least 8 µg/mL without affecting disease control. Of the 147 patients screened for inclusion in this study, 55 patients who had adalimumab concentrations >8 µg/mL were randomly assigned to either a dose-interval prolongation of once every 3 weeks or continuation of every other week dosing.
After 28 weeks, they found that the mean change in the disease activity score of 28 joints was −0.14±0.61 in the prolongation group and 0.30±0.52 in the continuation group. Thus, the mean difference (0.44, P =.01) was significantly in favor of prolonging the dosing interval to once every 3 weeks. No serious adverse events were reported, but 14 patients reported an adverse event in the continuation group as did 2 patients in the prolongation group.
“In conclusion, this study shows that patients with RA on adalimumab with serum trough concentrations above 8 μg/mL can safely prolong their dosing interval to every 3 weeks without loss of disease control” stated the investigators. In addition, drug costs could be reduced by 33% based on the cost of standard-dose adalimumab treatment in The Netherlands.
l’Ami MJ, Krieckaert CLM, Nurmohamed MT, et al. Successful reduction of overexposure in patients with rheumatoid arthritis with high serum adalimumab concentrations: an open-label, non-inferiority, randomised clinical trial. Ann Rheum Dis. 2018;77:484-487.