Effectiveness of intravenous tocilizumab in routine clinical practice in a cohort of Costa Rican patients with rheumatoid arthritis

OBJECTIVE

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 (4mg/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 3^rd 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 8mg/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 (4mg/kg) is an effective and safe treatment for RA patients in a clinical setting in Costa Rica.