138-AP-98
FOR IMMEDIATE RELEASE
Contact:Andrew Porterfield, (949) 824-3969, [email protected]
UC IRVINE RESEARCHER FINDS MINOR CARDIOVASCULAR ABNORMALITIES AMONG PATIENTS WHO TOOK REDUX/PHEN-FEN DIET DRUGS
Dallas, Nov. 11, 1998 - Patients who took the diet drug Redux (dexfenfluramine) or a drug combination known as "phen-fen" for longer than three months showed some cardiovascular abnormalities, but at levels not currently regarded as clinically significant, according to a study to be presented today by a UC Irvine College of Medicine researcher at the American Heart Association's Annual Scientific Sessions.
The study was sponsored by Wyeth-Ayerst Laboratories, the company that marketed Redux and Pondimin (Wyeth's trade name for fenfluramine). The combination of fenfluramine and another drug, phentermine, was commonly known as "phen-fen."
The study, presented by Dr. Julius M. Gardin, chief of UCI's Division of Cardiology, showed that patients taking the drugs for longer than three months had an increase in a cardiovascular problem called valvular regurgitation, or "leaking," but at levels that are currently not considered harmful. Patients who had taken the drugs for less than three months showed no increase in one form of regurgitation, but those taking phen-fen showed increases of a mild degree of another type of regurgitation. Further studies are planned to obtain additional data on these issues, Gardin said.
Gardin led the research group that compared 479 patients who had previously taken Redux and 455 who had taken phen-fen for at least one month with 539 people who had not taken either drug for five years prior to the study. Most of the patients in the study were obese women in their 40s. The researchers used results from previous medical histories, physical exams and echocardiograms, which create a picture of the heart's interior with sound waves.
Patients had taken the drugs for varying lengths of time. The average time of Redux use in the study was six months; the average duration of phen-fen use was nearly a year. By contrast, Wyeth market research data indicate that, when the drugs were on the market, more than 80 percent of the patients who took Redux and more than 70 percent of the patients who took phen-fen received the drug therapies for three months or less.
Among some of the study participants who had taken the drugs for longer than three months, the researchers observed aortic regurgitation, which is a backward flow of blood from the aorta that leaks into the pumping chamber on the left side of the heart. (The aorta is the main vessel leading from the heart to the body.) Specifically, the study found that:
∑ The overall rates of patients experiencing mild or greater aortic regurgitation were 8.9 percent of those taking Redux, 13.7 percent of those taking phen-fen and 4.1 percent of those not taking either treatment.
∑ Among patients who were treated for three months or less, there was no increase in mild or greater aortic regurgitation when they were compared to the untreated group.
∑ Among those treated for more than three months, 11.1 percent of patients taking Redux and 14.9 percent of phen-fen patients showed aortic regurgitation, compared to 4.1 percent of patients not taking treatments.
When looking at the patients' medical histories and physical exams, the researchers found no significant differences between untreated and treated patients in clinical signs of heart disease during the time the study took place. The researchers did find a statistically significant increase in mild regurgitation through another part of the heart known as the mitral valve, which connects the two chambers of the heart's left side. This increase was seen among patients taking phen-fen for less than three months, but not among the patients taking Redux for three months or less. In these cases, the mitral regurgitation was low-grade and considered clinically insignificant, the study showed.
The researchers found no differences between groups in elevations of pressure in the pulmonary arteries supplying blood to the lungs, and no thickening of heart valves was seen in any of the treated or untreated patients. In addition, the study recorded no additional diagnoses of infection of the heart's valves (known as endocarditis), and no heart surgery in any of the patients after the study treatments were concluded. Finally, the heart's ability to pump blood was normal in more than 98 percent of all patients studied.
"Serious cardiovascular events were rare in every group in the study-the Redux users, the phen-fen users and untreated patients. The absence of serious cardiovascular clinical problems in this large study is encouraging in the short term," Gardin said.
A full report of Gardin's findings will be submitted for publication.
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