Edaspidine

Edaspidine is a synthetic organosulfur compound that was initially developed in the early 1990s as a potential antiangiogenic agent for the treatment of solid tumors. Its chemical formula is C14H16NO4S, and it belongs to the class of heterocyclic thiazolidinones. The molecule contains a five‑membered thiazolidine ring fused to a substituted benzene core, with an oxamic acid side chain that confers acidic properties. The synthesis typically involves a condensation of 2‑(4‑chlorophenyl)‑thiazolidin‑4‑one with a protected oxamic acid derivative, followed by deprotection to yield the free acid.

In vitro studies have shown that edaspidine inhibits vascular endothelial growth factor receptor‑2 (VEGFR‑2) phosphorylation, thereby reducing endothelial cell proliferation and migration. Animal models of xenograft tumors displayed a dose‑dependent reduction in tumor volume and microvessel density when treated with edaspidine. Pharmacokinetic profiling in rodents revealed moderate oral bioavailability, a plasma half‑life of approximately 4–5 hours, and primary elimination through the kidneys. Toxicology data indicated a relatively low acute toxicity profile, with no lethal doses observed up to 2000 mg/kg in mice.

Despite encouraging preclinical results, edaspidine did not advance to late‑stage clinical trials. Regulatory hurdles included difficulty in establishing a consistent manufacturing process and limited evidence of therapeutic advantage over existing angiogenesis inhibitors. Consequently, development was halted in 2007, and the compound has remained a research tool rather than a marketed drug. Recent literature cites edaspidine in mechanistic studies of kinase inhibition, and its structural scaffold is being explored for the design of new antiangiogenic agents.