Background Monomethyl auristatin E (MMAE, vedotin) is a very potent antimitotic agent that inhibits cell division by blocking the polymerisation of tubulin. The family of auristatins are synthetic analogues of the antineoplastic natural product Dolastatin 10, ultrapotent cytotoxic microtubule inhibitors that are clinically used as payloads in antibody-drug conjugates. Antibody-drug conjugates enhance the antitumor effects of antibodies and reduce adverse systemic effects of highly potent cytotoxic agents.