Study: Most Failed Drug Trials Unpublished

Half or more of all supporting clinical trials for U.S. Food and Drug Administration approved medications stays unpublished five years after market approval, according to researchers at the University of California.

To obtain approval from the FDA, drug companies are required to submit two or more studies demonstrating a drug is safe and effective, even if other clinical trials have found it is not.

Researchers reviewed medical literature of 909 clinical trials for 90 drugs approved by the FDA between 1998 and 2000.

They discovered that 76 percent of pivotal trials – like that of large Phase II and Phase III trials which are designed to assess the risks vs. benefits of a drug – had been published in medical journals within three years of FDA approval. While, only 43 percent, of all supporting trials were published.

Selective reporting of clinical trial results was also found by researchers. For instance, trials with statistically significant results were more likely to get published then the trials with non-significant results, as were the trials with larger sample sizes. Or when a pivotal trial found a drug out performed an older drug.

The failure to publish both negative and positive trial results could skew doctors’ opinions about a drug, causing them to favor newer more expensive drugs, researchers said. While earlier studies have examined the publication patterns of antidepressants and pediatric drug studies, this is the first research to examine all drugs approved over a defined period of time.

The FDA Amendments Act of 2007 requires basic reporting of all FDA-approved drugs and devices when they start and that all outcomes are to be posted within a year of approval on the U.S. National Institutes of Health’s clinical trials website.

The study, “Publication of Clinical Trials Supporting Successful New Drug Applications: A Literature Analysis,” was published in the journal PLoS Medicine. #