ABT-199 sensitivity in primary human T-ALL patient samples. (A) ABT-199 IC₅₀ values for a panel of primary T-ALL samples. Patient samples are classified based on their immunophenotype in pro-, pre-, cortical, intermediate between cortical, and mature T-ALL with markers scored on the blast gate. Molecular classification is based on fluorescence in situ hybridization and/or expression analysis. (B) Cell viability of diagnostic and relapse material from T-ALL patient 16 after 16 hours of ABT-199 treatment using different concentrations relative to cells incubated with dimethylsulfoxide (100%). (C) BCL-2 expression (quantitative real-time polymerase chain reactions, calibrated normalized relative quantities values and corresponding standard errors) analysis of diagnostic and relapse material obtained from T-ALL patient 16. The expression was standardized against B2M, HPRT1, RPL13A, and TBP. (D) Percentage of human CD45 in the bone marrow of NSG mice injected with a patient-derived xenograft from T-ALL #3 (MLL rearranged, HOXA-positive) after 7 days of treatment with vehicle or ABT-199. /, not known; BM, bone marrow; cCD3, cytoplasmic CD3; p+, partial positive; R, relapse; s, surface; v, variable; w, weak. *P = .0498.