Despite last week’s worldwide recall of the popular diet drugs Redux and Pondimin, the concept of treating obesity with medication has not lost favor.
Patients and physicians say they’re eager for new drugs, and pharmaceutical companies say they are pushing ahead with obesity research. At least seven drugs are in development, two of which should be available next year.
The reaction reflects a shift in the concept of obesity itself. A generation ago, when the addictive dangers of amphetamines gave obesity drugs a bad reputation, being fat was seen primarily as a sign of a self-indulgent, sedentary lifestyle. Now, it is also recognized as a chronic disease to which some unlucky people are genetically predisposed - and which can be improved by long-term drug therapy.
Even experts who fault the Food and Drug Administration for narrowly approving Redux welcome new treatment options.
“To abandon the pharmacotherapy of obesity at this point would be throwing the baby out with the bathwater,” said George Ricaurte, a Johns Hopkins University neurologist who is studying the question, raised during approval hearings, of whether Redux is toxic to certain brain cells.
Redux, known chemically as dexfenfluramine, and Pondimin, known chemically as fenfluramine, have been linked to potentially lifethreatening heart-valve damage in users. Some experts speculate the problem is showing up now because physicians now recommend long-term, rather than short-term, use. (Dexfenfluramine is fairly new in this country, but fenfluramine was approved 24 years ago; both have been sold in Europe for many years.)
Another drug, phentermine - prescribed in recent years with fenfluramine in a combination called “fen-phen” - appears not to cause valve damage.
As these drugs have once again demonstrated, medical science has only begun to unlock the genetic and biochemical mysteries of obesity. Every breakthrough has led to new puzzles or unforeseen side-effects; every hope for a magic bullet has given way to renewed exhortations to eat less and exercise more.
Even leptin - the brain-signaling hormone that generated such excitement a few years ago when it turned fat, lethargic mice svelte and energetic - seems less than wondrous when given to fat humans. In early testing by Amgen Inc. of Thousand Oaks, Calif., subjects lost about 4 to 9 pounds after 90 days of leptin treatment - not much more than the 3 pounds lost by subjects treated with dummy medication.
Amgen officials said they are “encouraged” and hope to bring a drug to market in about four years.