Background Leflunomide has become of increasing value for the treatment of rheumatoidarthritis (RA), and leflunomideisused via its active metabolite teriflunomide. The European League Against Rheumatism (EULAR) suggestedthatboth LEF and methotrexatewerefundamentalmedicines for the treatment of RA.
Objectives To investigate the relationshipbetweenteriflunomideplasma concentrations and diseaseactivity in patients with RA.
Methods This was a cross-sectional multicenter study (four rheumatology departments) over a four years period.Patients withRA on a stable and dailyleflunomide dose for >2 monthswereincluded.
Socio-demographic data and clinical data were recorded. Respectively, disease status and functional disability were assessed by disease activity score (DAS28) and Health Assessment Questionnaire (HAQ). Treatment response was evaluated according to the EULAR criteria (variation of DAS28).
Quantitative determination of teriflunomide (active metabolite of leflunomide) plasma concentrationswas carried out by high-performance liquid chromatography with ultraviolet detection.
Results A total of 24 patients were enrolled; sex ratio =1. The mean age of the sample was 51,71 (±15,3) years; the mean disease duration at study baseline was 135,2 (±80,26) months; 70% of patients were RF positive, and 58% ACPA positive.The mean score on VAS pain was 43 mm (±22,92). Respectively, the mean swollen and tender joint counts (SJC-28, TJC-28) were4,3 (±6,1) and 2,8 (±3,09). The mean HAQ was 2,01 (±0,78). At baseline, the mean DAS28 score was 4,17 (±1,12); 56% weregood and moderate EULAR responders.
The mean leflunomide treatment duration was 34,94 months (±32,47). The meanteriflunomide plasma concentrations was 38,34 ug/ml (±24,92).
Residualteriflunomide plasma concentrations was significantly associated SCJ-28 and DAS28 decrease (p=0,0027). However, all these parameters (VAS pain, TJC-28, HAQ, C reactive protein, prescription duration of leflunomide and EULAR response) were not correlated with residualteriflunomide plasma concentrations.
Conclusions This studyconcludedthatresidualteriflunomide plasma concentration isassociatedwithlow active disease.
Disclosure of Interest None declared