Drug adherence, response and predictors thereof for tocilizumab in patients with rheumatoid arthritis: results from the Swedish biologics register

Objective. To evaluate drug adherence, clinical response and predictors thereof for tocilizumab in patients with RA in routine care based on prospectively collected data from the Swedish biologics register, Anti-Rheumatic Therapies in Sweden. Methods. RA patients who had started with tocilizumab from September 2008 until March 2012 were identified. Cox regression and logistic regression models were used. Results. A total of 530 RA patients were included, of whom 80.6% were female, 64.7% were on concomitant DMARDs, of which 300 were on MTX and 12% were biologic naive. The overall 6 month, 1 and 2 year estimated drug continuations were 79%, 64% and 50%, respectively. In the multivariate analyses, a low initial level of CRP [hazard ratio (HR) 0.76/1S. D. (95% CI 0.63, 0.91)], high HAQ score [HR 1.23/1S.D. (95% CI 1.06, 1.44)] and prior exposure to different biologics [HR 1.43 (95% CI 1.12, 1.83)] were predictors for drug termination, whereas concomitant DMARD therapy was not. European League Against Rheumatism (EULAR) good, moderate, and no response were achieved by 184 (46.7%), 133 (33.8%) and 77 (19.5%) patients, respectively. Predictors for EULAR good response vs no response (at 2.5-8 months) were low HAQ [odds ratio (OR) 0.56/1S. D. (95% CI 0.40, 0.78)], high 28-joint DAS [OR 2.0/1S. D. (95% CI 1.44, 2.78)] and not being on prednisolone [OR 0.47 (95% CI 0.25, 0.88)] at baseline. Conclusion. In this RA cohort treated with tocilizumab, the estimated 1 year drug continuation was 64% and 80% of the patients achieved a EULAR response. Drug discontinuation was not predicted by no concomitant DMARD, but by low CRP, high HAQ and prior exposure to biologics.