Failure to recruit

To investigate whether a reduced-dose dosing regimen (1x500mg semiannually) of rituximab (RTX) (Mabthera®) is non-inferior in patients with rheumatoid arthritis (RA) whose disease is in persistent low disease activity (LDA) or clinical remission (REM) (pLDA/pREM) as compared to the standard dosing regimen of 1x1000mg semi-annual infusions.

Randomized, controlled, single-centre study with 1x500mg or 1x1000 semi-annual infusions of RTX (Mabthera) as intervention and a follow-up period of 2 years. Patients as well as assessors will be blinded to the type of treatment. Patients in the 1x500mg group who experience a flare as defined by the disease activity score 28-ESR (DAS28) will receive 1x1000mg RTX (Mabthera) at their upcoming scheduled infusion appointment. Patients in the 1x1000mg group whose disease activity reaches DAS28 >3.2 during the duration of the study will be re-evaluated for a change in biological therapy and will discontinue the study.

Inclusion Criteria:

• Diagnosis of RA according to the 2010 American College of Rheumatology (ACR) / European League Against Rheumatism (EULAR) classification criteria
• Current treatment with RTX (at time of inclusion have already received at least 2 cycles of 1000mg RTX) at the Day-Clinic of the Division of Rheumatology of the Medical University of Vienna
• Persistent low disease activity or clinical remission as defined below
• Persistent clinical remission (pREM) will be defined as a simplified disease activity index (CDAI) (12) ≤2.8 measured at two time-points 6 months apart. The CDAI is calculated as follows: tender joint count (TJC) + swollen joint count (SJC) + patient's assessment of general health on a 100 mm visual analogue scale (GH) + evaluator's assessment of general health on a 100 mm visual analogue scale (EGH)
• Persistent low disease activity (pLDA) will be defined as a CDAI ≤10 measured at two timepoints 6 months apart Patients who achieve REM at only either one of the two successive time-points will be considered as having pLDA with regard to the current trial

Exclusion Criteria:

• Patients ≤ 18 yrs
• Patients receiving RTX for a disease other than RA
• Patients who fail to meet criteria for REM or LDA at either one of the two successive timepoints (i.e. having a disease activity >10 as measured by the clinical disease activity index, (CDAI))