OBJECTIVES: To examine the effectiveness of tocilizumab (TCZ) with and without synthetic disease-modifying antirheumatic drugs (sDMARDs) in a large observational study. METHODS: Patients with rheumatoid arthritis treated with TCZ who had a baseline visit and information on concomitant sDMARDs were included. According to baseline data, patients were considered as taking TCZ as monotherapy or combination with sDMARDs. Main study outcomes were the change of Clinical Disease Activity Index (CDAI) and TCZ retention. The prescription of TCZ as monotherapy was analysed using logistic regression. CDAI change was analysed with a mixed-effects model for longitudinal data. TCZ retention was analysed with a stratified extended Cox model. RESULTS: Multiple-adjusted analysis suggests that prescription of TCZ as monotherapy varied according to age, corticosteroid use, country of the registry and year of treatment initiation. The change of disease activity assessed by CDAI as well as the likelihood to be in remission were not significantly different whether TCZ was used as monotherapy or in combination with sDMARDs in a covariate-adjusted analysis. Estimates for unadjusted median TCZ retention were 2.3 years (95% CI 1.8 to 2.7) for monotherapy and 3.7 years (lower 95% CI limit 3.1, upper limit not estimable) for combination therapies. In a covariate-adjusted analysis, TCZ retention was also reduced when used as monotherapy, with an increasing difference between mono and combination therapy over time after 1.5 years (p=0.002). CONCLUSIONS: TCZ with or without concomitant sDMARDs resulted in comparable clinical response as assessed by CDAI change, but TCZ retention was shorter under monotherapy of TCZ.

Cantacuzino Hosp Bucharest Romania

DANBIO Center for Rheumatology and Spine Diseases Rigshospitalet Glostrup Denmark Department of Clinical Medicine Faculty of Health and Medical Sciences University of Copenhagen Glostrup Denmark

Department of Medicine Helsinki University Central Hospital and University of Helsinki Helsinki Finland

Department of Rheumatology Aarhus University Hospital Aarhus Denmark

Department of Rheumatology Diakonhjemmet Hospital Oslo Norway

Division of Rheumatology University Hospitals of Geneva Geneva Switzerland

Institute of Rheumatology and Clinic of Rheumatology Charles University Prague Prague Czech Republic

Institute of Rheumatology Moscow Russia

Radboud University Nijmegen Medical Centre Nijmegen the Netherlands

Rheumatology Department Hospital Clinic of Barcelona Barcelona Spain

Rheumatology Research Unit Instituto de Medicina Molecular Lisbon Portugal on behalf of the Rheumatic Diseases Portuguese Register

SCQM Foundation Zurich Switzerland

The Karolinska Institute Stockholm Sweden

University Medical Center Ljubljana Slovenia

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