An antibody-drug conjugate (ADC) composed of an antibody targeting CS1 (SLAMF7/CD319) that is conjugated to the microtubule-disrupting cytotoxic agent monomethyl auristatin E (MMAE), via a cathepsin-cleavable linker, with potential antineoplastic activity. Upon administration, the antibody moiety of azintuxizumab vedotin binds to CS1-expressing tumor cells and is internalized, thereby delivering MMAE intracellularly. Upon cleavage, MMAE binds to tubulin and inhibits its polymerization, resulting in G2/M checkpoint arrest and apoptosis in CS1-expressing tumor cells. CS1 is a cell surface glycoprotein belonging to the CD2 subset of the immunoglobulin superfamily (IgSF) and is expressed with high levels and prevalence on multiple myeloma (MM) cells.