Monomethyl Auristatin E (MMAE) is an antimitotic agent which inhibits cell division by blocking the polymerization of tubulin. Monomethyl Auristatin E is the synthetic analog of the antineoplastic natural product Dolastatin 10, cannot be used as a drug itself. Monomethyl Auristatin E is commonly conjugated with monoclonal antibodies directed at antigens specific to cancer cells for tumor-directed cytotoxicity. MMAE is typically coupled to the antibody via a protease-cleavable linker, allowing separation of the drug from the antibody following intracellular localization. When coupled to cAC10, Monomethyl Auristatin E shows selective cytotoxicity in CD30+ cells and induces G2/M-phase growth arrest and cell death through the induction of apoptosis. When coupled to the anti-CD79b antibody, anti–CD79b-vcMMAE has very potent and broad activity across a large panel of NHL cell lines in vitro. When coupled to the anti-HER2 antibody, pertuzumab-vc-MMAE can also be effectively internalized and potently kill HER2 over-expressing tumor cells. In the Karpas 299 ALCL model, cAC10-vcMMAE induces complete, durable tumor regression, while free MMAE doesn’t produce detectable antitumor activity. In mouse xenograft models of NHL, anti–CD79b-vcMMAE strikingly results in sustained complete tumor remission.