Last week, we discussed the FDA’s decision to severely restrict sales of the Type 2 diabetes drug rosiglitazone (brand name Avandia). Since the aim of these restrictions is to end widespread use of the drug, it appears that the three-year debate over Avandia’s safety is finally over. But it may be too early for the FDA — or for drug companies — to breathe a sigh of relief.
As a recent article in The New York Times points out, the Avandia controversy is the product of a new era in drug safety analysis — one in which the FDA and drug companies are not the only relevant parties. It is becoming increasingly common for the raw data obtained in drug trials, not just the final results, to be made publicly available online. Thus any scientist in the world can analyze it, using advanced and sometimes controversial statistical techniques to study outcomes that were not the original focus of the trials. The 2007 meta-analysis of Avandia by Dr. Steven Nissen of the Cleveland Clinic, which found an increase in heart attacks associated with the drug and ignited the Avandia controversy, did exactly this.
The problem with such after-the-fact studies, from the FDA’s perspective, is that their results are not as statistically sound as the randomized controlled trials that the agency uses in its drug approval process. Furthermore, the agency is not accustomed to having outside groups and scientists reach conclusions on drug safety — and these conclusions can make headlines and put pressure on the agency to act. In the case of Avandia, the agency acknowledged that Dr. Nissen’s and other findings on Avandia’s heart risks were compelling, but not definitive, and therefore took what it viewed as a sensible middle course by restricting but not banning the drug. But the FDA’s resources would be strained if it had to respond frequently to such third-party drug studies. Even if resources were not a problem, the agency could not issue custom, risk-appropriate restrictions on very many drugs without creating a confusing patchwork of regulations for doctors to follow.
At least in the case of diabetes drugs, though, the FDA has a plan to avoid this situation. As three top agency officials note in an
explanation of their decision on Avandia, published in the New England Journal of Medicine, in 2008 the FDA issued new guidelines for evaluating cardiovascular risk in new diabetes drugs. These guidelines recommend conducting trials that last at least two years and give boundaries above which it would consider various cardiovascular risks unacceptable, compared with the risks seen in “standard therapy.” Drug companies do not have to follow these guidelines, but if they do not, they must otherwise prove their drug’s cardiovascular safety to gain FDA approval.
What do you think — is the FDA right to introduce new standards for trials of diabetes drugs to gauge cardiovascular risk? How much higher a risk compared with “standard therapy” should be allowed? Is setting new, specific risk standards a slippery slope — leading to a possibly endless drug approval process — or a step in the right direction? Leave a comment below!