CAL-130

CAL-130 is a PI3Kδ and PI3Kγ inhibitor with IC₅₀s of 1.3 and 6.1 nM, respectively. IC50 & Target: IC50: 1.3 nM (P110δ), 6.1 nM (P110γ), 56 nM (p110β), 115 (p110α)^[1] In Vitro: CAL-130 preferentially inhibits the function of both p110γ and p110δ catalytic domains. IC₅₀ values of CAL-130 are 1.3 and 6.1 nM for p110δ and p110γ, respectively, as compared to 115 and 56 nM for p110α and p110β. CAL-130 does not inhibit additional intracellular signaling pathways (i.e., p38 MAPK or insulin receptor tyrosine kinase) that are critical for general cell function and survival^[1]. In Vivo: The clinical significance of interfering with the combined activities of PI3Kγ and PI3Kδ is determined by administering CAL-130 to Lck/Pten^fl/fl mice with established T cell acute lymphoblastic leukemia (T-ALL). Candidate animals for survival studies are ill appearing, have a white blood cell (WBC) count above 45,000 μL^-1, evidence of blasts on peripheral smear, and a majority of circulation cells (>75%) staining double positive for Thy1.2 and Ki-67. Mice receive an oral dose (10 mg/kg) of CAL-130 every 8 hr for a period of 7 days and are then followed until moribund. Despite the limited duration of therapy, CAL-130 is highly effective in extending the median survival for treated animals to 45 days as compared 7.5 days for the control group^[1].