DM4 (ravtansine) is a thiol-containing derivative of maytansine. It binds to tubulin and inhibits the assembly of microtubules. DM4 is being investigated as the cytotoxic payload of a number of antibody-drug conjugates (ADCs). This BSA-DM4 conjugate is designed with similar linker chemistry as commercial drug T-DM1 and is synthesized at CellMosaic