Hypoxic depth charge

Traditional chemotherapeutics kill rapidly dividing solid tumor cells that are close to the vasculature, where oxygen levels are normal. However, they do not penetrate deep into the hypoxic compartment of tumors where oxygen levels are low. This leaves residual cells that have been shown to acquire mutations that enable them to develop drug resistance and to metastasize.

A number of companies are developing compounds that target these hypoxic areas. Last Sunday, Threshold Pharmaceuticals Inc. disclosed preliminary data from two Phase I/II trials suggesting that its TH-302 hypoxia-activated prodrug (HAP) will complement chemotherapy...