Definition

An antibody-drug conjugate (ADC) comprised of an anti-CD205 (lymphocyte antigen 75; Ly75) humanized immunoglobin G1 (IgG1) monoclonal antibody conjugated to DM4, a maytansinoid microtubule disruptor, via a cleavable N-succinimidyl-4-(2-pyridyldithio) butanoate (SPDB) linker, with potential antineoplastic activity. Upon intravenous administration, anti-CD205 ADC OBT076 specifically targets and binds to CD205, a receptor involved in antigen capture and endocytosis, expressed on tumor cells. Following rapid internalization of the ADC/CD205 complex, OBT076 releases its DM4 payload due to cleavage of the SPDB linker by intracellular proteases. Then the DM4 binds to tubulin and disrupts microtubule assembly/disassembly dynamics, resulting in the inhibition of both cell division and cell growth of CD205-expressing tumor cells. CD205, a type I transmembrane surface glycoprotein belonging to the C-type lectin receptor family, is normally expressed on various antigen-presenting cells (APCs) and some leukocyte sub-populations but it is overexpressed in multiple cancer types where it plays a key role in facilitating metastatic invasion.