An antibody-drug conjugate (ADC) composed of AGS67C, a human anti-CD37 monoclonal antibody covalently linked, via reduced cysteines and a protease cleavable linker, to monomethyl auristatin E (MMAE), an auristatin derivative and a potent microtubule disrupting agent, with potential antineoplastic activity. Upon administration, the monoclonal antibody moiety of AGS67E binds to CD37 antigens on tumor B-cells and is rapidly internalized, thereby delivering MMAE intracellularly. Upon proteolytic cleavage, MMAE binds to tubulin and inhibits its polymerization, resulting in G2/M checkpoint arrest and apoptosis in CD37-expressing tumor cells. CD37, a transmembrane glycoprotein, is overexpressed in B-cell malignancies.