BCL2L1 and acute lymphoblastic leukemia: XZ739 showed improved potency compared to DT2216, induced apoptosis in T-ALL cell lines and displayed indications for senolytic activity,415 indicating on-target activity.416 While SIAIS361034 binds both BCL2 and BCL-XL, it only degrades BCL-XL and has proven selective in hepatocellular carcinoma.417,418 XZ424 is also a CRBN-based PROTAC, but instead of the dual inhibitor ABT-263 it uses the selective BCL-XL inhibitor A1155463.