For an activity that seems to come so naturally to so many Americans, getting fat is actually quite complicated. Not surprisingly, then, so is developing a pill that will help reverse that process.
Day after day, the appetite must be energized and the urge to eat activated -- frequently, and for the right foods. These foods must be eaten in volume, digested and rendered into usable form as fuel. Energy used in daily activity must not exceed available stores. And unused calories must be deposited as love handles, thunder thighs, double chins and pot bellies.
In principle, there's good news in that calculus. Disrupt that complex process at any step along the way and -- voila! -- the obese patient should begin inching his or her way toward a healthy weight. In the multibillion-dollar sweepstakes to discover or develop an effective medication to combat obesity, scientists and drug makers have many points to target.
For those awaiting weight-loss help from a physician's prescription pad, the result is a panoply of candidate medicines.
Since 1997, the FDA has approved only two weight-loss medications -- sibutramine (marketed as the prescription drug Meridia) and orlistat (marketed as the over-the-counter fat-blocker Alli). PhRMA, the drug manufacturers' trade association, counts about 35 more candidates under development -- from the embryonic to the nearly hatched. Many are in wide use to treat other conditions, including epilepsy, vertigo and high blood pressure. Some are variants of psychiatric drugs that are known to have weight loss as a side effect. A few are novel agents that may reverse weight gain -- and some of its medical consequences -- in ways never tried before.
Ken Johnson, senior vice president of PhRMA, says that drug developers and manufacturers are scrambling to find ways to lessen the health effects of obesity. Johnson underscores the importance of proper diet and lifestyle management in weight reduction and disease prevention. But, he adds, "Several new treatments in the research pipeline . . . may help."
Complex challenges
But the complexity of becoming overweight poses remarkably steep challenges to drug developers. With so many systems at work in the fat-making process, different people climb the BMI charts for different reasons.
A sweet tooth might be one person's biggest vulnerability. An inability to push the plate away -- say, because of inattention to feelings of fullness -- might be another's. A third might wring every calorie from food consumed, quickly storing the excess as fat.
