Medical scientists in California have reported that more than half of all supporting trials for medicines licensed by the US Food and Drug Administration (FDA) remain unpublished five years after approval. It would be interesting to know how this compares with the situation in Europe.
Kirby Lee, Peter Bacchetti and Ida Sim at the University of California, San Francisco, carried out a search of medical journals to determine the publication status of 909 clinical trials which supported 90 new FDA drug approvals in the years 1998 to 2000.
The researchers found that only 394 (43%) of those trials had been published. They also uncovered evidence of selective reporting of trial results, such as the non-publication of research showing that a new drug performs no better than an old one. This practice can, they say, lead to preferential prescribing of newer and more expensive medicines.