Safety evaluation to support First-In-Man investigations I: Kinetic and safety pharmacology studies

Kinetic (in vitro, pharmacokinetic, mass balance and toxicokinetic studies) and safety pharmacology data available in 34 Investigator’s Brochures used to support First-In-Man clinical trials over a 10 year period have been evaluated to give an insight into the types of study designs used and how these have changed over the period analysed (1997–2006). For kinetic evaluation, study packages often had single dose pharmacokinetic studies in the rodent and non-rodent by oral and intravenous dose routes as well as protein binding measurement accompanied more recently by rodent mass balance studies and an examination of in vitro metabolism across species and/or enzyme activity with hepatocytes, liver microsomes or recombinantly expressed enzymes. Toxicokinetic data were examined from key repeat dose toxicity studies in rodents and non-rodents with the recent inclusion of sampling in control animals to check for drug contamination. For safety pharmacology evaluation, study packages included “core battery” rodent central nervous system as well as anaesthetised non-rodent cardiovascular and respiratory function studies. More recently, cardiovascular assessment occurred in conscious non-rodents, necessitating stand-alone rodent respiratory function studies although conscious models assessing both cardiovascular and respiratory function were also seen in some of the most recent packages. Recent packages also had an in vitro electrophysiology study, usually the hERG assay. Considerations for kinetic and safety pharmacology study designs are discussed.