KS18

KS18 is a selective small molecule inhibitor of the anti-apoptotic protein Mcl-1 (Induced myeloid leukemia cell differentiation protein), currently under investigation for the treatment of multiple myeloma (MM). It is particularly noted for its potential to overcome resistance to standard-of-care agents such as bortezomib and venetoclax. KS18 employs a dual regulatory mechanism to reduce Mcl-1 levels: it suppresses Mcl-1 transcription by inhibiting the STAT-3 signaling pathway and promotes Mcl-1 protein degradation through the ubiquitin-proteasome system (UPS) via phosphorylation and ubiquitination. This depletion of Mcl-1 triggers the intrinsic apoptotic pathway, leading to caspase-dependent cell death in myeloma cells. Preclinical studies in patient samples and mouse models have demonstrated significant anti-tumor activity and a favorable safety profile, suggesting its potential as a therapeutic option for relapsed or refractory multiple myeloma.