Clinical study failures vary widely by clinical phase of and therapeutic class; study

While lack of commercial viability is the leading cause of Phase I clinical trial failures for new drug candidates, efficacy issues dominate as the reason for Phase II failures, according to a new analysis from the Tufts Center for the Study of Drug Development.

Based on a study of products that entered clinical development from 2000 through 2009, Tufts CSDD found that commercial reasons accounted for 40.9% of all Phase I failures, but only 27.3% of Phase II failures. Efficacy issues explained 50.9% of Phase II failures. Clinical study failures also vary widely by therapeutic class of drugs being investigated, the analysis showed.

"It is in the interest of drug developers to have new products fail earlier, rather than later, in development, as earlier terminations avoid the costs of larger, more complex studies," said Joseph DiMasi, Tufts CSDD director of economic analysis, the principal investigator on the study.

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