VcMMAE (mc-vc-PAB-MMAE), a MMAE derivative with valine-citrulline (Vc) linker,is an Drug-linker Conjugate for antibody-drug conjugate (ADC) with potent antitumor activity. MMAE is a synthetic antineoplastic agent and can be efficiently released from VcMMAE in vitro and exert cytotoxic activity.