[Biological markers: utilization in drug development and approval]

The objectives of the reflection on biomarkers are far ahead of the issues of surrogacy, and constitute a major stake for pharmacology: enhancement of the liability of positive or negative screening for candidate drugs, speed-up of development processing, accurate identification of responders to a specific drug, and optimization of drug monitoring. Examples illustrate the situations where biomarkers are useful: diagnosis, prognosis, prediction of therapeutic response, either favourable or unwanted. The advance of pharmacogenetics leaves hope for optimization of drug use through the adaptation of drug choice to an individual profile. Some deficiencies have been identified concerning policies of transfer, evaluation or interdisciplinary validation. The optimization of the use of highest level evidence data, which is possible when appropriate biomarkers and clinical data are systematically collected during all the steps in drug development, the formal modelling of physiological, pathological and pharmacological processes and their assessment through computer simulation, and the simultaneous conduct of pragmatic and cognitive approaches, appear to be the necessary conditions for fulfillment of the objectives defined above.