A proprietary, hypoxia-activated prodrug with potential antineoplastic activity. Upon administration, the hypoxia-activated prodrug TH-4000 is activated in the hypoxic cells within tumors into an irreversible pan-HER inhibitor via a mechanism of action not yet fully elucidated. As a result, this agent inhibits cellular proliferation and differentiation of tumor cells overexpressing HER kinases, which belong to the epidermal growth factor receptor (EGFR) family of receptor tyrosine kinases. Healthy, normal tissues may be spared due to the hypoxia-specific activity of this agent, potentially reducing systemic toxicity. Check foractive clinical trials using this agent.