Methionine aminopeptidase 2 (MetAP2, inhibitor)

Class

polymer-drug conjugate (poly(methacrylamide)-based backbone with a cathepsin-cleavable GFLG linker) delivering the fumagillin-class small-molecule MetAP2 inhibitor SDX-7539; designed to avoid the CNS toxicity and short half-life of earlier small-molecule fumagillin derivatives

Pathway

irreversible MetAP2 inhibition blocks N-terminal methionine excision from nascent proteins, producing anti-angiogenic, anti-tumor, anti-metastatic effects and favorable metabolic/insulin-sensitizing effects; alters intratumoral cell-cycle and immune-response gene expression

Methionine aminopeptidase 2 (MetAP2) is an intracellular enzyme that removes the initiator methionine from the N-terminus of newly synthesized proteins, a processing step required for many proteins to fold, localize, and function correctly. Irreversible inhibition of MetAP2, historically achieved with fumagillin-derived small molecules, was found to selectively impair proliferating endothelial cells, giving these agents pronounced anti-angiogenic activity: they starve tumors and other pathological tissues of new blood vessel growth, which in turn limits tumor expansion and metastatic spread. Independently, MetAP2 inhibition alters lipid and glucose handling, producing insulin-sensitizing and weight-reducing effects that have been explored in metabolic disease. The therapeutic challenge with earlier fumagillin-class inhibitors was that they crossed into the central nervous system and had short circulating half-lives, causing neurologic side effects and requiring frequent dosing. This mechanism entry represents an engineering solution: the MetAP2 inhibitor is chemically attached to a water-soluble polymer backbone through a linker cleaved specifically by cathepsin, a protease abundant in tumor lysosomes. The conjugate circulates as a large, CNS-excluded reservoir and releases active drug preferentially where the cleaving enzyme is concentrated, aiming to preserve the anti-angiogenic and metabolic benefits of MetAP2 blockade while reducing systemic and neurologic exposure.