is investigating whether the Food and Drug Administration's drug-review process cleared GlaxoSmithKline PLC's diabetes pill Avandia and Merck & Co. Inc. and Schering-Plough's cholesterol drug Vytorin without sufficient proof of their safety or effectiveness.
The Iowa Republican Sen. Charles Grassley said Tuesday the Government Accountability Office has agreed to study a much-debated method for approving drugs used to clear Avandia and Vytorin. The Senators investigation after recent studies suggested the drugs may not lower the risk of heart attack and artery-clogging plaque, as assumed by millions of patients and doctors.
"There's enough of a pattern of problematic drugs to ask for an independent review of how the FDA follows up on the effects of medicines that it's approved," said Grassley, in a statement.
FDA cleared Avandia because it helped control blood sugar, which many doctors believe decreases diabetics' risk of heart attack. But the agency came under fire last year when an analysis showed Avandia could actually increase heart attack risk.The agency approved Vytorin, which combines Schering-Plough's Zetia with Merck's older cholesterol drug Zocor, based on its cholesterol-lowering capability. But a study released earlier this year showed Vytorin was no more effective at limiting plaque buildup in neck arteries than Zocor alone, which is now available as a low-cost generic.
Last month FDA cleared Genentech Inc.'s drug Avastin for use in breast cancer patients who have not taken other drugs. Agency reviewers based their decision on Avastin's ability to slow the spread of cancer. Previously FDA had approved drugs as a first-choice option for cancer patients if they extended, or improved the quality, of patients' lives.
Sen. Charles Grassley's Letter to GOA;
February 28, 2008
The Honorable David M. Walker
U.S. Government Accountability Office
441 G St, NW
Washington, D.C. 20548
Dear Comptroller Walker:
The Food and Drug Administration (FDA) has approved several drugs that appear to have little to no effect in protecting lives and increasing health. For instance, FDA recently approved Genentech's cancer drug, Avastin, to treat breast cancer. Genentech's studies showed that Avastin halted tumor growth, but that breast cancer patients did not live significantly longer than those that did not receive the drug. Surprisingly, FDA's own advisory panel argued against the approval over concerns that Avastin's benefits do not outweigh its toxic side effects.
Further, a study last year found that Avandia, which controls glucose levels, was associated with an increased risk of heart attack. And last month, Schering-Plough and Merck announced that Vytorin, which controls cholesterol levels, provided no benefit to cardiovascular outcomes.
In all three cases, these drugs were approved by FDA because they had an effect on surrogate endpoints (tumor growth for Avastin; glucose levels for Avandia; and cholesterol levels for Vytorin). However, none of these drugs were studied sufficiently to see if they added any benefit to the health and/or lifespan of the patient. Typically, such results can be found through phase IV trials.
Therefore, I request that the Government Accountability Office conduct an inquiry into the FDA's approval of drugs based on surrogate endpoints, including an examination of FDA's process to ensure that drugs approved on surrogate endpoints are both safe and effective. In particular, GAO's inquiry should include an analysis of the following:
C The number of drugs that were approved based on surrogate endpoints;
C The surrogate endpoints that FDA uses to approve drugs;
C For each of these drugs identified, the date each was approved and whether FDA required the companies to complete phase IV trials;
C For each of these phase IV trials, the date they were started and the date they were completed and/or are expected to be completed;
C Describe the tools that FDA has to compel companies to complete phase IV trials;
C Describe any actions that FDA has taken against companies for failing to complete phase IV trials or failing to complete trials in a timely manner; and
C Describe any additional powers that FDA may need to compel companies to complete phase IV trials, in the event the tools that FDA has presently are insufficient.
Thank you for your attention to this important matter.
Charles E. Grassley
United States Senator
Ranking Member of the Committee on Finance
Parts Copyright 2008 The Associated Press.
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