Survival curves of SCID mice bearing disseminated Burkitt lymphoma (Daudi) treated with hA20IgG-(LL2scFv)2 and compared with those treated with the parental hA20 IgG (veltuzumab). Mice were administered intraperitoneally twice weekly for 3 weeks 1 day after Daudi inoculation (1.5 × 107 cells intravenously) with one of 4 different doses of hA20IgG-(LL2scFv)2 or the molar equivalent doses of hA20 IgG.