A targeted antibody drug conjugate (ADC) consisting of a human monoclonal antibody directed against the epidermal growth factor receptor (EGFR) conjugated to the cytotoxic agent maytansinoid mertansine (DM1), with potential antineoplastic activity. Upon intravenous administration, the monoclonal antibody moiety of AVID100 binds to EGFR on tumor cell surfaces. Following receptor internalization, the mertansine moiety binds to tubulin and interferes with microtubule assembly/disassembly dynamics. This inhibits both cell division and proliferation of cancer cells that express EGFR. EGFR, overexpressed by a variety of cancers, plays a key role in tumor cell proliferation and survival.