Thyroid Drug Approval is Questionable
FDA says drug maker needs government OK to keep selling it
FRIDAY, June 1, 2001 (HealthDayNews) -- Levothyroxine sodium is a little-regulated thyroid drug with a history of problems that's been on the market for 40 years. Now, the Food and Drug Administration wants the only U.S. manufacturer that has yet to gain approval to sell the drug to get that OK before it can keep marketing it.
Abbott Laboratories has yet to provide information to the FDA on its version of levothyroxine sodium, which the company calls Synthroid -- the third most frequently prescribed drug in the U.S.
Back in August 1997, the FDA published a notice saying the drug needed safety testing and approval. The agency later extended the deadline for Abbott to submit the information to Aug. 14, 2001.
"Whether this drug will be subject to be taken off the market if the company does not meet the Aug. 14 deadline is still up in the air," says Susan Cruzan, an FDA spokeswoman in Washington, D.C. "What we are saying is that the Federal Register notice did ask manufacturers to submit their new drug applications. And as I understand it, that notice did not include a provision that related to only submitting an application by Aug. 14, but stated the drug needed to be approved by that date."
"Abbott will be submitting a New Drug Application (NDA) in accordance with FDA guidelines in order to ensure that the eight million patients effectively treated with Synthroid have continued access to their medication. Abbott has notified the FDA of its intent to submit its NDA and is working cooperatively with the agency to meet the filing timeframes," the company said in a statement today.
Synthroid holds 85 percent of the market and had sales of $541 million in 2000.
Levothyroxine sodium is prescribed to patients who have an underactive thyroid. The thyroid is in the front of the neck near the Adam's apple and produces hormones that control the body's metabolism. In hypothyroidism, the body's metabolism slows down, patients often feel tired, gain weight and have muscle pain. Other symptoms include anything from loss of hair and hoarseness to constipation and memory problems.
According to the FDA, reports of problems with levothyroxine sodium's potency began to crop up in the mid-1990s. That prompted the agency to tell the drug's three manufacturers -- Abbott, Tennessee-based King Pharmaceuticals Inc., and Calif.-based Watson Pharmaceuticals Inc. -- they would have to submit new drug applications establishing the drug's safety.
Because patients with hypothyroidism need finely tuned doses of the drug, any potency problems could cause the thyroid to function at less -- or more -- than the best level. Both King and Watson followed the FDA's request and have already received approvals for their versions of levothryoxine sodium.
Abbott may have misread the Federal Register notice, says the FDA.
"The interpretation seems to be they just need to make a submittal," Cruzan says. "But they need to get it approved; it can't just be a submittal. The agency has made no final decisions on what actions it may take on Aug. 14. We are considering our options, and we have not made a determination at this point that we would take the drug off the market."
The Gray Panthers, an activist group of older Americans, says the process has gone on far too long.
"The way we look at it, the FDA four years ago, after a series of complaints, said the drug had to go through a new regimen of testing," says Tim Fuller, executive director of the Gray Panthers, based in Washington, D.C. "If the drug's maker had done the testing at that time, they would be free and clear. But [we] suspect that they didn't do it because they were not confident that the drug would pass the test.
"Now it's four years later, and they still haven't done it," he says. "Their competitors have, and the FDA has approved their versions. But the current FDA finding that the drug is not safe or effective still stands. From our point of view, Synthroid should not be on the market past the deadline that has been extended for [Abbott] to Aug. 14, especially since there are alternatives."