Effects on B cells in cynomolgus monkeys treated with combination rIL-21 and rituximab.

The trapezoidal method was used to calculate peripheral cell counts over time (AUC) for the first 7–8 days of each dosing cycle and normalized to a daily average cell count. Graphs show CD20^high and CD20^low cells in animals treated with vehicle, weekly rituximab (0.05 mg/kg), rIL-21 (0.5 mg/kg for 3 days), or rituximab co-administered before the first rIL-21 dose in each cycle (days 1, 8, and 20). (B) Rituximab in combination with rIL-21 decreased the counts of CD20^low B cells, compared to rIL-21 alone, after the second dosing cycle. Open bars indicate rIL-21 dosing days; rituximab was co-administered before the first rIL-21 dose in each cycle (days 1, 8, and 20, indicated by asterix). Note: scales are expanded for control and rituximab-treated groups compared to rIL-21-treated group. (B) Percentage change in normalized CD20^low B cell counts after each dosing cycle. (*p<0.05, repeated measures ANOVA comparing combination groups to 0.5 mg/kg rIL-21 group only). Error bars show SEM. (A, B) N = 3 animals/group.