Definition

An antibody-drug conjugate (ADC) composed of an asymmetric, bivalent, biparatopic antibody targeting two independent epitopes of folate receptor alpha (FRa; FolRa; FOLR1) that is conjugated, via a cleavable peptide linker, to the cytotoxic maytansinoid derivative DM21, with potential antineoplastic activity. Upon administration of anti-FRa/DM21 ADC IMGN151, the antibody moiety targets and binds to FRa expressed on tumor cells. Upon cellular uptake and internalization, DM21 is released, binds to tubulin and disrupts microtubule assembly/disassembly dynamics, which results in the inhibition of both cell division and cell growth of tumor cells. FRa is a glycosylphosphatidylinositol-linked cell surface glycoprotein, that is widely expressed in certain cancers while its expression is limited in normal tissues.