This ADC product is comprised of an anti-CD19 monoclonal antibody (B496) conjugated via a Mc linker to MMAF. The MMAF is targeted to certain cancers by immunerecognition and delivered into cancer cells via receptor mediated endocytosis. Within the cell, MMAF binds to tubulins, interrupts microtubule dynamics, and subsequently, induces cell death. Peptide linkers, belonging to Enzymatically cleavable linkers, combine greater systemic stability with rapid enzymatic release of the drug in the target cell. The scission of peptidic bonds relies on lysosomal proteolytic enzymes, which have very low activities in blood due to endogenous inhibitors and the unfavorably high pH value of blood. Derived from Auristatin,are water-soluble dolastatin analogs of dolastatin 10. Dolastatin 10 belongs to dolastatin family and it can powerfully bind to tubulin, thus inhibiting polymerization mediated through the binding to the vinca alkaloid binding domain, and causes cell to accumulate in metaphase arrest.