SLM6 is a sangivamycin-like molecule. SLM6 is a CDK9 inhibitor. SLM6 inhibits CDK9/cyclin K and CDK9/cyclin T1 kinase activity with IC 50 s of 280 nM and 133 nM, respectively. SLM6 also inhibits CDK1/cyclin B and CDK2/cyclin A with IC 50 s of less than 300 nM. SLM6 induces apoptosis in multiple myeloma (MM) cells.