The FDA’s standards for approving new drugs are inconsistent and lacking in important areas, according to an analysis conducted by researchers from Yale University and published in the Journal of the American Medical Association.
“Not all FDA approvals are created equally,” researcher Nicholas Downing said.
According to the researchers, the study is the first to systematically examine the FDA’s drug approval standards, and it calls into question the assumption that all drugs prescribed in the United States are safe or effective.“Based on our analysis, some drugs are approved on the basis of large, high-quality clinical trials, while others are approved based on results of smaller trials,” senior author Joseph Ross said. “There was a lack of uniformity in the level of evidence the FDA used.”
Many approvals based on single study
In order to evaluate the FDA’s drug approval process, the researchers examined publicly available agency documents regarding 188 new drugs approved between 2005 and 2012. These therapies were approved for the treatment of a total of 206 conditions, based on 448 efficacy studies.
“FDA review of new drug applications is guided by the Federal Food, Drug, and Cosmetic Act, which requires ‘adequate and well controlled investigations’ to determine efficacy,” the researchers wrote.
“Many patients and physicians assume that the safety and effectiveness of newly approved therapeutic agents is well understood; however, the strength of the clinical trial evidence supporting approval decisions by the [FDA] has not been evaluated.”
The researchers found that the vast majority of trials were randomized (89 percent) and double-blinded (79.5) percent, factors considered key parts of the most reliable studies. However, only 55 percent of the studies met the third “gold standard” criterion of placebo control. A full 13 percent of the studies used to approve new drugs used no control group at all.
In one of the most surprising findings, fully 37 percent of all new drugs were approved based on just a single study. Another 38 percent were approved based on two studies, while only 25 percent were approved based on three or more studies.
The findings of a single study are not considered a valid basis for drawing firm conclusions within standard scientific practice.
Another problem with many of the approvals was their reliance on studies that did not follow patients for very long. Fully 66 percent of all new drugs were approved without the evidence of a single study lasting six months or longer. This is a significant concern, since many serious side effects take months or years to develop.
Nearly half the drugs – 45 percent – were approved without any direct evidence that they led to the desired outcome. Instead, the drugs were approved based on studies showing that they acted on some correlate of the condition to be treated.
“[M]any… trials were small, short, and focused on lab values, or some other surrogate metric of effect, rather than clinical endpoints like death,” Downing said.
No comparative data
The researchers criticized the fact that the FDA does not require drug makers to compare the effectiveness of new drugs to other drugs already on the market. Only 40 percent of new drugs underwent such comparative testing.
Comparative tests are “an important step for determining whether the new drug is a better option than existing, older drugs,” Ross said.
The study casts doubt on the common assumption that FDA-approved drugs are all safe and effective, the researchers warned.
“Based on our study of the data, we can’t be certain that this expectation is necessarily justified, given the quantity and quality of the variability we saw in the drug approval process,” Downing said.
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