Pharmacogenetics ultimately may make some Phase III trials smaller by enabling companies to enroll fewer patients with known polymorphisms correlated to drug response. But at least in the short run, the argument can be made that many earlier stage trials will have to be larger in order to find those polymorphisms in the population.

The European Agency for the Evaluation of Medicinal Products (EMEA) recently published a report to the Committee for Proprietary Medicinal Products (CPMP) on the use of pharmacogenetic testing in the drug development process (see Online Links, BioCentury, Aug. 7). The publication noted that while pharmacogenetic testing may lead to a smaller number of patients being investigated in Phase III trials, "it is unclear how many patients will be required in Phase I and