The pharmacokinetic effect of coadministration of apremilast and methotrexate in individuals with rheumatoid arthritis and psoriatic arthritis

Apremilast is a novel agent for the treatment of inflammatory based autoimmune disorders. The objective of this study was to assess the pharmacokinetic effects of co administration of apremilast and methotrexate on both agents. This was an open-label, multi-center, 3-treatment period, sequential study conducted in otherwise healthy subjects with psoriatic arthritis or rheumatoid arthritis who were receiving a stable oral dose of methotrexate between 7.5 to 20 mg once weekly. Subjects received their dose of methotrexate on Days 1 and 8 of the study in addition to Apremilast 30 mg oral every 12 hours on Days 3-8. Pharmacokinectic profiles of methotrexate and 7-OH methotrexate were characterized after methotrexate alone (Day 1) and after co-administration of methotrexate and Apremilast (on Day 8). The pharmacokinetic profile of Apremilast was characterized after Apremilast alone (on Day 7) and after co-administration of methotrexate and Apremilast (on Day 8). The 90% confidence interval of the ratio of the geometric means for the Cmax and AUC parameters for methotrexate, 7-OH methotrexate, and Apremilast alone and after co-adminstration are all within the FDA acceptance range for equivalency (80-125%). This study showed that methotrexate and apremilast can be co-administered without any effect on the pharmacokinetic exposure of either agent.