Multi-species toxicology approaches for oncology drugs: the US perspective.

The Toxicology and Pharmacology Branch (T&PB) of the National Cancer Institute (NCI) performs pharmacological and toxicological evaluations of new oncology agents according to an agent-directed paradigm in which all studies are tailored to each agent. The United States Food and Drug Administration (US FDA) requires that preclinical toxicology studies be conducted in two species, a rodent and a non-rodent for all small molecules, and T&PB has successfully used this formula. While pharmacokinetic (PK) studies are considered optional, T&PB routinely develops new methods for plasma/tissue drug analysis and employs this methodology throughout development to determine kinetics in various species and toxicokinetics in the toxicity studies. In the current era of molecular target-based development, the T&PB also develops or employs methodology to evaluate effects of the new chemical entity on appropriate biomarkers in tumour and normal tissues. In this comprehensive programme, T&PB is able to correlate safety and toxicity with both plasma drug levels and biomarker modulation in two species for a seamless entry into Phase I.