Figure 4

In vivo activity of IgG1 and IgG2σ C47B222-(CHO) in primary AML and xenograft mouse models. (a) NSG mice were implanted with the indicated AML patient samples. Bone marrow aspirates were analyzed 5 weeks later for engraftment, mice were randomized and treatment was initiated (n=10/group). IgG1 and IgG2σ C47B222-(CHO) were administered twice weekly (10 mg/kg) for 3 weeks. BM and spleen were collected on day 21 and analyzed via FACS to assess leukemic cell burden (hCD45+CD3− cells). (b) Ten million HL60 cells were implanted into NSG mice (n=10/group) on day 0 and mice received twice weekly treatments (20 mg/kg), starting day 6 after implant until study end. (c) Five million MV4-11 cells were implanted into NSG mice (n=10/group) on day 0 and mice received twice weekly treatments (20 mg/kg), starting day 6 after implant until study end. For both (b) and (c), survival was monitored, and bone marrow and spleen were collected on day 28 (HL60) and day 35 (MV4-11) and analyzed via FACS to assess leukemia burden (hCD45+ cells). Increased life span (ILS) was calculated as follows: ((treatment median survival−control median survival)/control median survival) × 100; Statistical significance was assessed by unpaired t-test vs PBS control (*P<0.05, **P<0.01 and ***P<0.0001; NS, non-significant).