Superior B-cell depletion in cynomolgus monkeys with GA101 treatment compared with rituximab. The efficacy of GA101 at depleting B cells in cynomolgus monkeys was compared with that of rituximab in groups of 3 animals. GA101 (2 × 10 mg/kg, ■; and 30 mg/kg, ) was compared with rituximab (2 × 10 mg/kg, ) and vehicle (□) after 2 intravenous doses administered on days 0 and 7 to male and female cynomolgus monkeys (n = 3 per group; 1 female, 2 males). Peripheral blood and lymph node B-cell numbers were evaluated at baseline (day −7) and on the indicated days by flow cytometric analysis. B-cell numbers were evaluated in the spleens of the treated animals on day 35. (A) Mean B-cell numbers expressed as B-/T-cell ratios in peripheral blood of cynomolgus monkeys treated with GA101 and rituximab. (B) Mean B-cell numbers expressed as B-/T-cell ratios in the lymph nodes of cynomolgus monkeys treated with GA101 and rituximab. (C) Mean B-cell numbers expressed as B-/T-cell ratios in the spleens of cynomolgus monkeys treated with GA101 and rituximab on day 35. GA101 treatment resulted in statistically superior depletion of total B cells from lymph nodes, compared with rituximab, from days 9 to 35, with a decrease in B-cell numbers of more than 95%. Data are mean ± SD.