From In the Pipeline today, there is a report on a study that looked at success rates of phenotypic screening (cell or bio assays) and target-based approaches for discovering new drugs -- 100 were discoverd via targeted approaches and 58 through phenotypic screening.
In examining the results from first-in-class small molecules, 28 were discovered via the screening route and 17 by targeted approaches -- despite a strong preference by the industry for the latter approach. The authors concluded that without adequate knowledge of the mechanism molecular of action (MMOA), the targeted approaches were not as effective and led to higher failure rates. They called into question the notion that all targets can provide the basis for a drug (industry paradigm). The extreme focus down this path may result in less effort being applied to develop relevant screenign assays which in fact could be more effective as a discovery tool.
The blog author (Derek Lowe) concludes that the NIH's translational medicine initiative may be able to add value if it devotes more effort to the development of relevant phenotypic screens.
Posted by Bruce Lehr July 7th 2011.