BCL2 and B-cell chronic lymphocytic leukemia: The penetration of the selective BCL2-inhibitor venetoclax (Venclyxto®) through the blood–brain barrier was also poor; however, it corresponded to the in vitro IC50 of the drug in an adult, male chronic lymphocytic leukemia patient diagnosed with trisomy 12, IGHV unmutated (VH4L) chronic lymphoid leukemia and experiencing a CNS relapse.