Tratamiento con rituximab en pacientes con artritis reumatoide en la práctica clínica. Estudio RITAR

La artritis reumatoide (AR) es una enfermedad sistémica autoinmune que produce inflamación crónica articular. La prevalencia global es 0,50-1,00% en adultos. La AR es una enfermedad compleja e implica factores ambientales que desencadenan la enfermedad en individuos genéticamente susceptibles, destacando el tabaquismo, la periodontitis por Phorphyromonas gingivalis y otros microorganismos. La AR es una enfermedad simétrica poliarticular bilateral que cursa con dolor, inflamación y rigidez matutina. El diagnóstico es principalmente clínico, se debe realizar una exploración clínica completa y pruebas de laboratorio (VSG, PCR, FR, ACPA). El tratamiento contempla uso de fármacos antirreumáticos modificadores de la enfermedad (FAME) sintéticos convencionales, biológicos o dirigidos. Rituximab (RTX) es un anticuerpo monoclonal quimérico que se une específicamente al CD20 de células B y produce lisis celular. El tratamiento no es curativo, precisa la administración de ciclos sucesivos aunque el esquema no está claramente establecido..

Experience with the use of Rituximab for the treatment of rheumatoid arthritis in a tertiary Hospital in Spain: RITAR study

There is evidence supporting that there are no relevant clinical differences between dosing rituximab 1000 mg or 2000 mg per cycle in rheumatoid arthritis (RA) patients in clinical trials, and low-dose cycles seem to have a better safety profile. Our objective was to describe the pattern of use of rituximab in real-life practice conditions. Methods: Rituximab for RA in clinical practice (RITAR) study is a retrospective cohort study from 2005 to 2015. Eligibility criteria were RA adults treated with rituximab for active articular disease. Response duration was the main outcome defined as months elapsed from the date of rituximab first infusion to the date of flare. A multivariable analysis was performed to determine the variables associated with response duration. Results: A total of 114 patients and 409 cycles were described, 93.0% seropositive and 80.7% women. Rituximab was mainly used as second-line biological therapy. On demand retreatment was used in 94.6% of cases versus fixed 6 months retreatment in 5.4%. Median response duration to on demand rituximab cycles was 10 months (interquartile range, 7–13). Multivariable analysis showed that age older than 65 years, number of rituximab cycles, seropositivity, and first- or second-line therapy were associated with longer response duration. The dose administered at each cycle was not significantly associated with response duration. Conclusions: Our experience suggests that 1000 mg rituximab single infusion on demand is a reasonable schedule for long-term treatment of those patients with good response after the first cycles, especially in seropositive patients and when it is applied as a first- or second-line biological therap