S553

S553 (also known as S65487) is a potent, selective, and orally bioavailable small-molecule inhibitor of Myeloid Cell Leukemia 1 (MCL-1), an anti-apoptotic member of the BCL-2 protein family. MCL-1 plays a critical role in cell survival by sequestering pro-apoptotic proteins; its overexpression is a common feature in various cancers and a major driver of resistance to BCL-2 inhibitors like venetoclax. S553 functions as a BH3 mimetic, binding with high affinity to the BH3-binding groove of MCL-1, which releases pro-apoptotic proteins such as BAK and BIM to trigger mitochondrial outer membrane permeabilization and subsequent apoptosis. Developed by Servier, S553 is being investigated primarily for the treatment of hematological malignancies, including acute myeloid leukemia (AML) and multiple myeloma, both as a monotherapy and in combination with other targeted agents.

Other names

MCL1 inhibitor S553MCL-1 inhibitor S553MCL 1 inhibitor S553