This ADC product is comprised of an anti-CD22 monoclonal antibody (clone RFB4) conjugated via a Mc-VC-PABC linker to MMAE. The MMAE is targeted to certain cancers by immunerecognition and delivered into cancer cells via receptor mediated endocytosis. Within the cell, MMAE binds to tubulins, interrupts microtubule dynamics, and subsequently, induces cell death. Noncleavable linkers, is considered noncleavable-meaning linker cleavage, and payload release does not depend on the differential properties between the plasma and some cytoplasmic compartments. Instead, the release of the cytotoxic drug is postulated to occur after internalization of the ADC via antigen-mediated endocytosis and delivery to lysosomal compartment, where the antibody is degraded to the level of amino acids through intracellular proteolytic degradation. "Derived from Maytansinoid,a group of cytotoxins structurally similar to rifamycin, geldanamycin, and ansatrienin. The eponymous natural cytotoxic agent maytansine is a 19-member lactam (ansa

macrolide) structure originally isolated from the Ethiopian shrub Maytenus ovatus. Maytansinoids can bind to tubulin at or near the vinblastine-binding site, which interfere the formation of microtubules and depolymerize already formed microtubules, inducing mitotic arrest in the intoxicated cells."