A 52-week, open-label study evaluating the safety and efficacy of tabalumab, an anti-B-cell-activating factor monoclonal antibody, for rheumatoid arthritis.INTRODUCTION
 The objective of this study was to evaluate the long-term safety and efficacy of tabalumab, a monoclonal antibody that neutralizes membrane-bound and soluble B-cell-activating factor, in rheumatoid arthritis (RA) patients.


 Patients in RCT1 received intravenous placebo, 30-mg tabalumab or 80-mg tabalumab every 3 weeks, and patients in RCT2 received subcutaneous placebo or 1-, 3-, 10-, 30-, 60- or 120-mg tabalumab every 4 weeks (Q4W).  Regardless of prior treatment, all patients in this study received subcutaneous 60-mg tabalumab Q4W for the first 3 months, then a one-time increase to 120-mg tabalumab Q4W (60-mg/120-mg group) and a one-time decrease to 60-mg tabalumab Q4W per patient was allowed (60-mg/120-mg/60-mg group).


 Pretabalumab baseline disease activity was generally higher in the 60-mg/120-mg group.  Both groups demonstrated efficacy through 52 weeks of treatment relative to baseline pretabalumab disease activity based on American College of Rheumatology criteria improvement ≥20%, ≥50% and ≥70%; European League against Rheumatism Responder Index in 28 joints; Disease Activity Score in 28 joints-C-reactive protein; and Health Assessment Questionnaire-Disability Index.


 With long-term, open-label tabalumab treatment, no unexpected safety signals were observed, and B-cell reductions were consistent with previous findings. 
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