Wyeth-Ayerst recalls diet drugs

At the request of the Food and Drug Administration, Wyeth-Ayerst Laboratories, a subsidiary of American Home Products, has voluntarily pulled Redux® (dexfenfluramine) and Pondimin® (fenfluramine) from the pharmaceutical market.

The Philadelphia-based company announced its decision less than one month after researchers at the Mayo Clinic, Rochester, MN, published an alarming report in the New England Journal of Medicine. The report tentatively linked combined use of fenfluramine and phentermine (a pairing commonly known as "fen-phen") with 24 cases of a rare form of valvular heart disease.

Redux - discovered by Interneuron Pharmaceuticals Inc., Lexington, MA, produced by Boehringer-Ingelheim, Ridgefield, CT, and marketed by Wyeth-Ayerst since April 1996 - was not mentioned in the original report, but additional preliminary data submitted to the FDA suggests a dexfenfluramine-phentermine combination may also be dangerous.

The additional data was submitted after the agency issued a warning to the public and requested feedback from physicians in July. Several physicians performed echocardiograms on concerned patients using fenfluramine-phentermine or dexfenfluramine-phentermine combinations and then submitted their results to the FDA. According to the agency, the data revealed that "of 291 asymptomatic patients screened, about 30% had abnormal valve findings, primarily aortic regurgitation."

Phentermine products have not been removed from the market. The FDA said it has not found sufficient data to indicate that the product, when used alone, causes heart valve disease.

Bottom-line backlash

Prior to the report, prescriptions for both products had been on the rise. According to IMS America, Plymouth Meeting, PA, the number of prescriptions for Pondimin was up from 50,000 in 1991 to more than 7 million in 1996. Sales jumped from $611,000 in 1991 to $134 million last year. And Redux, which was launched mid-1996, raked in annual sales in excess of $130 million.

Within weeks of the report, however, the number of prescriptions for the products dropped significantly. The number of prescriptions for Pondimin dropped 56% and those for Redux fell 35%.

American Home Product's one-time cost of pulling the two products from the market may be $200 to $300 million.

Sales reps who promoted Redux will not be affected by the withdrawl, said Doug Petkus, a spokesperson for Wyeth-Ayerst. Sales reps were not marketing Pondimin because it was already well-established in the market. According to Petkus, the company has no plans to expand or decrease its sales force at this time. PR