CAL-101 is a potent PI3K p110δ inhibitor with an IC50 of 65 nM. CAL-101 blocked constitutive phosphatidylinositol-3-kinase signaling, resulting in decreased phosphorylation of Akt and other downstream effectors, an increase in poly(ADP-ribose) polymerase and caspase cleavage and an induction of apoptosis. CAL-101 has 40 to 300-fold selectivity compared to other PI3K isoforms.
In vitro studies of 0.1 to 10 µM CAL-101 showed inhibition of pAKT expression and/or apoptotic effects against primary chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML) cells and against a range of leukemia and lymphoma cell lines. [1][2]