ABT-263 is a BH3 mimetic that inhibits Bcl-2, Bcl-ω, and Bcl-xl. ABT-263’s inhibition of Bcl-xl results in thrombocytopenia by inducing apoptotic death of platelets, limiting its usage. ABT-263 exhibits anticancer chemotherapeutic activity and shows some benefit in clinical trials. In chronic lymphocytic leukemia (CLL) cells, ABT-263 inhibits cell proliferation. In cellular and animal models of cancers with solid tumors, ABT-263 enhances the chemotherapeutic activity of several co-administered treatments.