Anti-NaPi2b Antibody-drug Conjugate YL205

**Semantic type:** Pharmacologic Substance

**Definition:** An antibody-drug conjugate (ADC) composed of a humanized monoclonal antibody directed against human sodium-dependent phosphate transport protein 2B (SLC34A2; NaPi2b), conjugated, via a protease-cleavable tripeptide linker, to a topoisomerase-1 inhibitor (TOP1i; TOP-Ii), with potential antineoplastic activity. Upon administration of anti-NaPi2b ADC YL205, the antibody moiety targets and binds to NaPi2b expressed on tumor cells. Upon binding, cellular uptake and linker cleavage, the TOP1i moiety is released. The TOP1i inhibits DNA topoisomerase I activity, thereby inhibiting DNA replication and generating DNA single- and double-strand breaks. This leads to cell cycle arrest and tumor cell apoptosis. In addition, ADC YL205 is able to induce a bystander effect on neighboring tumor cells. This inhibits the proliferation of NaPi2b-expressing tumor cells. NaPi2b, a tumor-associated antigen (TAA), is overexpressed on a variety of cancer cells and plays a key role in the transport of inorganic phosphate (Pi) and the maintenance of phosphate homeostasis.

**Synonyms:** - ADC YL205 - Anti-NaPi2b ADC YL205 - Anti-NaPi2b/TOP1i ADC YL205 - YL 205 - YL-205 - YL205