ATLANTA (CNN) -- A major study released Tuesday found no sign that brief use of the diet pill Redux causes heart valve disease -- as was feared when the drug was pulled from the market last September.
The study of a sustained-release form of dexfenfluramine, known as Redux, involved more than 1,000 patients and found no significant increase in the prevalence of heart valve regurgitation after two to three months, Dr. Neil Weissman of the Georgetown University Medical Center told a meeting of the American College of Cardiology.
Valvular regurgitation is the backward leakage of blood, which can decrease blood flow to the rest of the body and increase the workload on the heart.
"These results should be reassuring for the majority of patients who have been on Redux," Weissman said.
However, the study did not rule out the possibility that taking Redux for many months, as it was intended to be used, could have harmed people. It also did not examine whether the chemically similar fen-phen -- pulled from the market at the same time as Redux -- is bad for the heart valves.
The study was sponsored by Wyeth-Ayerst Research. Wyeth-Ayerst Laboratories, which makes both Redux and fen-phen, pulled both drugs off the market at the request of the Food and Drug Administration. The government acted after a Mayo Clinic team reported 24 cases of heart valve problems among people taking fen-phen.
Government agencies eventually gathered several hundred cases of damaged heart valves among people taking fen-phen and Redux. Such reports cannot prove that the diet drugs actually caused the valve damage. However, the FDA estimated that one-third of people taking the pills could have suffered significant heart valve damage as a result.
'Reassuring' for some
Dr. Janet Woodcock of the FDA said that while the new study "is reassuring for people who took it for a short period of time," it does not settle the question of what happened to those who use Redux longer. She said the FDA believes longer-term use is where most of the harm occurred.
The study involved 1,072 patients who were testing the safety of a long-acting form of Redux.
The patients were randomly assigned to take regular Redux, the new form of Redux or dummy pills. Neither the doctors nor the patients knew what they were getting.
The study was stopped when Redux was taken off the market, and the patients were then given echocardiograms to check their heart valves. The doctors who read their scans did not know which treatment they had received.
Results showed no significant difference among the three groups in the kind of serious valve damage that the FDA had warned of in Redux patients.
Researchers said there was a slightly higher incidence of valvular regurgitation in patients who had been taking Redux in its original form or the new sustained-release version than in patients given a placebo, but they said the difference was not statistically significant.
Weissman said three out of four people in the general population have minor amounts of valve leakage.
The patients took the drug for an average of 77 days, which is about the same length of time that three-quarters of Redux patients used the drug.
Furor likely to persist
The findings are unlikely to quell the furor over Redux.
"This leaves the false impression that these drugs are safe," said Guerry Thornton, an Atlanta attorney who has filed lawsuits for women who used them.
Dr. Richard Bowen, a Naples, Florida, doctor who sent 122 cases of apparent valve damage to the FDA, said that while the new study is reassuring to those who used the drug briefly, he worries that valve problems may be more common among those who took Redux for longer periods of time.
A spokesman for Wyeth-Ayerst said the company has decided not to reintroduce Redux. "Given the legal environment, it doesn't make any sense," said Dr. Philip J. de Vane.
Hundreds of lawsuits have been filed against the company by people who took Redux or fen-phen. The government estimates between 1 million and 5 million Americans have taken the diet drugs.
Cnn.com
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