Therapeutic drug monitoring of teriflunomide: do plasma concentrations predict response to leflunomide in patients with rheumatoid arthritis?

OBJECTIVES: Leflunomide is a commonly used treatment for rheumatoid arthritis. It acts by inhibiting dihydroorotate dehydrogenase through its active metabolite teriflunomide. The objective of the study was to investigate the relation between plasma-concentration of teriflunomide and disease-activity in rheumatoid arthritis. METHODS: Data were collected from patients with rheumatoid arthritis on a stable leflunomide dose for at least 2 months. Socio-demographic data, disease characteristics and DAS28 score were recorded. Blood samples were taken for determination of teriflunomide concentration. RESULTS: A total of 32 serum concentration-time measurements were collected. The concentration of teriflunomide was positively correlated with disease duration of RA (r2=0.2264) and the number of swollen joints (r2=0.2413). There was a trend towards a positive correlation between Health Assessment Questionnaire (HAQ) and plasma teriflunomide concentration (r2=0.1699). Weight was negatively correlated with the residual plasma concentration of teriflunomide (r2=0.2483). However, there was no significant correlation between residual-plasma-concentration of teriflunomide and the following parameters: age, sex, number of tender painful joints, patient-global-assessment, C-reactive protein (CRP) and duration of prescription of leflunomide. We did not find association between disease-activity and residual-plasma-concentration of teriflunomide (r2=0.0021) and haven't been able to define the threshold value of residual-plasma-concentration of leflunomide predictive of a good-response. CONCLUSIONS: We did not find a concentration-effect-relationship. However, therapeutic drug monitoring of teriflunomide may be useful to ensure adherence and evaluate toxic-levels in case of adverse-events.

[Epidemiology and clinical profile of knee osteoarthrosis in the elderly]. / Profil épidémioclinique de la gonerthrose sujet age.

BACKGROUND: Osteoarthris represents one of the most frequent degenerative pathologies. Its prevalence increases with the age as well as the functional consequences which are more considerable at the elderly population. aim : study the epidemiology and clinical features of knee osteoarthritis of older patient. methods: retrospective study made in the department of physical and rehabilitation medicine of the military Tunis hospital, on a sample of 60 patients having osteoarthritis, divided in two groups, the one is constituted by 30 subjects of 65 and more years old, other one of 30 adults aged between 30 and 55 years old. All the patients had a clinical and functional evaluation. results: the comparison between both groups showed a statistically significant difference (P < 0.05) in the following items: the severity of the pain, the bilateral hydarthrosis, the muscular strength of quadriceps, hamstrings and their retraction, the severe reduction of walking perimeter, and the bicompartimental lesion of both knees. CONCLUSION: clinical and sociofunctional features of knee osteoarthritis in the elderly patient require adapted and multidisciplinary management, in order to avoid the potential impact of knee osteoarthritis on the function and quality of life of the patient.