FRI0201 Analysis of infection risk in patients with limited return of peripheral B cells after a period of 2 years or more following any rituximab treatment course in RA clinical trials

Objectives To evaluate the infection risk and long-term safety of prolonged peripheral CD19+ B cell depletion (BCD) following rituximab (RTX) treatment in RA clinical trials. Methods Subgroups of patients (pts) with peripheral BCD from the RTX All Exposure population were analysed. Infection rates (from first RTX exposure until last valid observation, including safety follow-up) were compared to overall infection rates in “All Exposed” and “anti-TNF inadequate responder (TNF-IR)” pts. During the 2 yr period of BCD, pts did not receive additional RTX therapy, although some pts were subsequently retreated. B cell (CD19+) levels were measured every 4-12 wks, depending on clinical study protocol. Results As of Sep 2010, 3194 pts (All Exposure) had been treated with RTX (11962 patient-yrs [PY]), of whom 41% (n=1324) were TNF-IR pts. Limited return of peripheral B cells (defined as CD19 count less than lower limit of normal [LLN;