1 The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; 2McGill University Health Centre, Department of Medicine, Quebec, Canada Royal Victoria Hospital, room L2-05, 687 Pine avenue West, Montreal H3A 1A1, QC, Canada
Drug development is a high risk activity where the return on investment is not granted. Progressive changes of the healthcare and pharmaceutical landscape resulted in a new environment that makes more difficult to release novel or innovating drugs to the market. For various reasons, we have entered ten years ago a period of drought for novel drug application . It is even more dramatic when one considers the field of central nervous system for which the percentage of new drug reaching the market was eight percent in 2004, constituting by far the lowest success rate among all the therapeutic areas . Indeed, despite billions of dollars spent in drug development, developing drugs aiming at the central nervous system suffers from one of the highest failure rate. The main reason lies in the blood-brain barrier which represents a hurdle that has proven, so far, very hard to jump.