Association Between Methotrexate Erythrocyte Polyglutamate Concentration and Clinical Response in Rheumatoid Arthritis Patients Treated With Subcutaneous Injectable Methotrexate

Overview

Methotrexate (MTX) is the first-line treatment of rheumatoid arthritis (RA). In case of MTX failure, it is discussed to start a Biologic Disease-modifying Antirheumatic Drug (bDMARDs) according to the latest European recommendations of the EULAR. Before to add a Biologic Disease-modifying Antirheumatic Drug (bDMARDs), an objective estimation of MTX impregnation could be carried out by MTX polyglutamates (MTX-PG). In rheumatoid arthritis patients with active disease estimated by DAS28 (Disease activity Score 28)\> 3.2 insufficiently controlled by MTX subcutaneously and patients in remission obtained with a DAS 28 \<2.6 with methotrexate prescribed since more than 6 months at stable dose for at least 3 months, a concentration of MTX-PG will be achieved.

The assumption is the association between low methotrexate erythrocyte polyglutamate and low clinical response in rheumatoid arthritis patients treated with subcutaneous injectable methotrexate. Adherence to MTX will be assessed by the Compliance Questionnaire Rheumatology (CQR). Measurement of this adherence could optimize MTX treatment prior to the use of biotherapy which is costly with a lower infectious tolerance. Correlation between its concentration and compliance assessed by CQR questionnaire will be tested.

Conditions