Incomplete data may mislead doctors into overprescribing expensive medicines

Thursday, September 25, 2008

Medical doctors have not been getting the full picture about newly FDA-approved drugs, concludes a research team from the University of California, San Francisco. This is because not all the studies required for FDA approval get published. New drug studies that do see publication tend to be ones where the medicine appears to perform well while poor and middling results are less likely to appear in medical journals. The result appears to be that doctors who read the available literature may get an inflated impression of new medications and may prescribe expensive new drugs in place of older medicines that perform as well or better. As Jordan Lite of Scientific American wonders, are drug companies cherry-picking the studies they publish to make their drugs look better than they actually are?

The University of California team reviewed trials that had supported new drugs approved from 1998 to 2000 and examined 909 trials of 90 medications. The search was conducted upon PubMed and other search tools that a typical medical doctor or patient could access. They concluded that less than half of the studies had been published five years after drug approval and a publication bias existed.

Erick Turner, who coauthored a similar study earlier this year, expressed concerns to Scientific American that the problem was not merely the raw percentage of studies published, but that a disproportionate share of the research that appeared in journals are examples where new medications appear to perform well:

When trials are selectively published … it will skew the efficacy of the drug and make it look like it works better than it does. It’s going to create a lot more enthusiasm among consumers of that information or in the words of Alan Greenspan, ‘irrational exuberance.’

Ken Johnson, senior vice president of the Pharmaceutical Research and Manufacturers of America (PhRMA), defended the pharmaceutical industry by saying FDA review of new drug applications is more important than publishing the results of medication trials in medical journals. Approved medications come with labels that give patients and doctors enough information, assures Mr. Johnson.

Yet concerns about full and appropriate disclosure have been serious enough that a new law was enacted last year. FDA Amendments Act of 2007 (FDAAA) requires that all trials which support FDA-approved drugs be registered at the National Institutes of Health website. The requirement goes into effect this coming Saturday. Congress enacted the legislation in response to hearings that determined pharmaceutical companies were less likely to publish studies that indicated significant side effects. One shortcoming in the legislation, according to UCSF associate professor Ida Sim, is that the FDA is still not required to specify which trials it weighs when considering applications for drug approvals. Yet she praises the new law as a major improvement. It’s critically important that we know trials exist and that we get the summary results, positive and negative, into the public domain—that’s a huge step and more than any [other] country is doing now.