ICH S9: Developing anticancer drugs, one year later.

International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) S9 is the first international regulatory guidance document devoted to a specific therapeutic area, highlighting its importance in harmonizing regulatory expectations for the nonclinical development of therapeutics designed to treat advanced cancer. ICH S9 successfully outlines the core requirements for the nonclinical development of novel oncology therapeutics, and the unique risk-benefit considerations for expediting drug development to treat these most grievous diseases. However, development companies and regulatory agencies have had limited opportunity to apply this guidance, so our collective experience in developing therapeutics under the guidance is limited. Discussed here are several key areas of ambiguity in the guidance, including identification of the patient population, selection of the initial safe dose for first-in-human trials, and requirements for nonclinical recovery data.