Ombrabulin

Ombrabulin (INN), also known as AVE8062, is a synthetic water-soluble prodrug that is converted in the body to its active form, AVE8062A. This active metabolite is a vascular disrupting agent (VDA) designed to target and disrupt the blood vessels of solid tumors. By inhibiting the tumor's blood supply, ombrabulin aims to starve tumors of the necessary oxygen and nutrients needed for their growth and survival.

Mechanism of Action

Ombrabulin exerts its effects through a mechanism distinct from that of traditional chemotherapy agents. As a prodrug, it is inactive until metabolized in the body to its active form, AVE8062A. This metabolite selectively targets and accumulates in the newly formed blood vessels that supply tumors, sparing most normal tissues. Once bound to the endothelial cells lining the tumor vessels, AVE8062A disrupts the cytoskeleton of these cells, leading to rapid vascular collapse and tumor necrosis due to lack of blood flow. This process is known as vascular disruption, and agents like ombrabulin that induce this effect are termed vascular disrupting agents (VDAs).

Clinical Development

Ombrabulin was under investigation for its potential in treating various types of solid tumors, including sarcoma, ovarian cancer, and non-small cell lung cancer (NSCLC). Clinical trials aimed to evaluate the efficacy, safety, and tolerability of ombrabulin, both as a monotherapy and in combination with other anticancer agents. Despite initial promise, the development of ombrabulin has faced challenges. As of the last available reports, the clinical development of ombrabulin has been discontinued due to insufficient efficacy in pivotal trials.

Pharmacokinetics

The pharmacokinetic profile of ombrabulin involves its conversion to the active metabolite AVE8062A following administration. This conversion allows for the targeted action of the drug. The pharmacokinetics of ombrabulin and its metabolites have been studied in the context of its clinical trials, providing insights into its absorption, distribution, metabolism, and excretion (ADME) properties.

Adverse Effects

Like other anticancer agents, ombrabulin can cause a range of adverse effects. The most common side effects observed in clinical trials included fatigue, nausea, and hypertension. More severe adverse events, such as cardiotoxicity and hemorrhage, have also been reported, underscoring the need for careful monitoring of patients receiving this treatment.

Future Perspectives

The discontinuation of ombrabulin's development highlights the challenges in the field of cancer therapy, particularly in the development of vascular disrupting agents. However, the concept of targeting tumor vasculature remains a promising area of research. Future efforts may focus on identifying new targets within the tumor vasculature, improving the selectivity and safety profiles of VDAs, and combining these agents with other therapies to enhance their efficacy.

See Also

• Vascular disrupting agent
• Prodrug
• Tumor microenvironment
• Chemotherapy