GA101 induces superior PS exposure and cell death induction compared with rituximab in the annexin V/PI FACS assay. Z138 NHL cells were seeded and treated with 10 μg/mL GA101 or rituximab for 24 hours. The graphs depict the mean percentage of total annexin V–positive, PI-negative (AnnV⁺) cells and annexin V/PI double-positive cells (AnnV⁺/PI⁺; n = 3). (A) Cell death induction by GA101 compared with B-ly1, camptothecin, and the type I anti-CD20 antibody rituximab. (B) Cell death induction by GA101 can be reduced to the level of rituximab by reintroducing the L11V mutation in the elbow-hinge region of the antibody.