Efectividad del tocilizumab intravenoso en la práctica clínica usual de una cohorte de pacientes costarricenses con artritis reumatoide

espanolObjetivo Determinar la efectividad y la incidencia de eventos adversos graves del tocilizumab (TCZ) en una cohorte de pacientes costarricenses con artritis reumatoide (AR) Pacientes y metodos Se realizo un analisis retrospectivo de 45 pacientes con AR, refractarios al uso previo de farmacos modificadores de la enfermedad reumatica (FAME), que utilizaron TCZ a una dosis inicial de 4 mg/kg intravenoso (IV) cada 4 semanas en asociacion con metotrexato o leflunomida. La medida de efectividad fue la incidencia de remision clinica, determinada cada 3 meses y definida por un puntaje de actividad de la enfermedad en 28 articulaciones con velocidad de sedimentacion globular (DAS28-VSG) menor de 2,6. La seguridad del farmaco se evaluo mediante la tasa de incidencia de eventos adversos severos. Se realizo un modelo de regresion logistica uni- y multivariado para determinar las variables asociadas con la probabilidad de remision a los 3 meses de iniciado el tratamiento. Resultados A los 3 meses de tratamiento un total de 22 pacientes (48,9%; intervalo de Confianza [IC] del 95%: 34,3-63,5%) alcanzaron remision, en tanto que a los 12 meses de terapia con TCZ el valor aumento a 34 pacientes (75%; IC 95%: 62,3-87,6%). Un total de 18 pacientes (40%; IC 95%: 25,7-54,3%) requirieron aumento de dosis del TCZ de 4 a 8 mg/kg ante la ausencia de remision. La tasa de incidencia de eventos adversos severos fue de 0,98 por 100 pacientes/ano, correspondiendo todos ellos a cuadros infecciosos que resolvieron sin ningun desenlace fatal. Solo el DAS28-VSG inicial se asocio de forma independiente con la probabilidad de remision a los 3 meses. Conclusiones El uso de TCZ IV a una dosis inicial de 4 mg/kg en pacientes costarricenses con AR es efectivo y seguro en la practica clinica. EnglishObjective To determine the effectiveness and the incidence of severe adverse events in a cohort of Costa Rican patients with Rheumatoid Arthritis (RA) treated with intravenous (IV) tocilizumab (TCZ). Patients and methods A retrospective analysis was carried out in 45 patients that were unresponsive to disease-modifying antirheumatic drugs (DMARDs). The study included patients who received IV TCZ every 4 weeks (4 mg/kg) along with methotrexate or leflunomide. Effectiveness was measured through the incidence of clinical remission according to a disease activity score - erythrocyte sedimentation rate (DAS28-ESR) less than 2.6. Safety was assessed by the incidence rate of serious adverse events. An univariate and multivariate logistic regression analysis was performed to assess the association of potential variables with the probability of achieving remission during the first 3 months of TCZ therapy. Results During the 3rd month of TCZ therapy, a total of 22 patients (48.9%; 95% Confidence Interval (CI) 34.3-63.5%) achieved remission. The cumulative incidence of patients with remission at month 12 was 75.0% (n = 34) (95% CI: 62.3-87.6%). A total of 18 patients (40%; 95% CI: 25.7-54.3%) were switched to a 8 mg/kg dose due to the absence of remission. The incidence rate of serious adverse events was .98 per 100 patients/year, all of them due to infectious diseases with no fatal events reported. Only basal DAS28-ESR was associated with the probability of achieving remission at month 3. Conclusions IV TCZ (4 mg/kg) is an effective and safe treatment for RA patients in a clinical setting in Costa Rica.