Lay summary
Mismatch between oxygen supply and demand results in tumour hypoxia (low oxygen), a major impediment to successful treatment outcomes in cancer management. Chemotherapies that are activated in oxygen-limiting regions of tumours can kill these aggressive cancer cells and so improve treatment outcomes. However, the design criteria to create an optimal hypoxia-selective chemotherapy agent are complex and sophisticated multi-parameter modelling is required. Leveraging many years of experience, we have created a promising new candidate and seek to understand its properties and define its clinical utility. Importantly the drug is orally bioavailable, well tolerated and appears highly selective for hypoxic cancer cells. This is the first time an agent that meets all the theoretic design criteria for a successful hypoxia-selective chemotherapy has been invented. Demonstrating its ability to accurately target tumour hypoxia, a 40 year old unsolved problem, represents a major milestone in this field.