Pubdate: Wed, 14 Aug 2002 Source: Wall Street Journal (US) Copyright: 2002 Dow Jones & Company, Inc. Contact: http://www.wsj.com/ Details: http://www.mapinc.org/media/487 Author: Hollister H. Hovey Bookmark: http://www.mapinc.org/pot.htm (Cannabis) MARIJUANA 'MUNCHIES' EFFECT AIDS OBESITY DRUG RESEARCH French pharmaceutical company Sanofi-Synthelabo hopes scientific knowledge gained from marijuana will help the masses curb the "munchies." The company reasons that if smoking pot makes people hungry, a compound that blocks the hunger-inducing effects of marijuana could make a great diet drug . Hence, the development of Sanofi's experimental obesity treatment Rimonabant. Such a drug , should it move beyond its current clinical trials and win approval, could contract waistlines while fattening Sanofi's sales. The National Institutes of Health estimates that one-quarter of the country is officially obese and more than half is overweight. Prescription diet drugs brought in $417 million in the U.S. last year, a relatively small amount that underscores the lack of a serious blockbuster in the marketplace. IMS Health, a market-research firm for the pharmaceutical industry, estimates that the market for prescription diet drugs will climb to $1.4 billion by 2010. Rimonabant's chemistry is based on the discoveries that scientists have made about the links between marijuana and hunger. With a weed-induced high comes a voracious urge to eat, which tokers refer to as the munchies. Doctors initially thought marijuana affected the brain in a fairly random manner, like alcohol, and that hunger was one of those random effects. But in the late 1980s, researchers discovered that the hypothalamus, the part of the brain that controls functions like movement, memory, perception and hunger, is covered in receptors that serve as docking stations for cannabis molecules. When marijuana chemicals settle into the receptors, the brain gets the message that the body needs food. But these receptors aren't sitting there waiting for a person to light up a joint. The human body makes its own marijuana-like substances called cannabinoids, which doctors now know play a large part in giving us an appetite. Based on this premise, Sanofi's researchers found a synthetic compound called a cannabinoid receptor antagonist that caps off the receptors, preventing cannabinoids from locking on and sending the "feed-me" message. Curbing the Urge George Kunos, a neurobiologist with the NIH's National Institute on Alcohol Abuse and Alcoholism, led a 2001 animal study on cannabinoids and eating habits. "Using genetically engineered mice which lacked the CB1 cannabinoid receptor sites, we found as expected that the normal animals, when briefly food restrained, ate more than the animals that lacked the cannabinoid receptor," Dr. Kunos said. "This was very strong evidence that the increase in food intake is mediated in part by this system." Dr. Kunos's study then showed that blocking off the receptors with Sanofi's compound produced the same results as the mice who lacked the receptors -- less of an urge to feed. After seeing the successful results in animals, Sanofi started to test the treatment on people who qualified as clinically obese. In a 16-week Phase IIB trial, Sanofi studied patients on various oral doses of Rimonabant compared with patients receiving a placebo. The heavier the dose, the more weight was lost, with a decrease of around 8.8 pounds at the end of the trial in the highest dose group. Rimonabant caused some gastrointestinal side effects at the highest dose, but was generally well-tolerated, a Sanofi spokesman said. Long-Term Issues It has yet to be seen if Sanofi's drug can help patients shed pounds over the long term and prevent them from gaining the weight back. Other potential weight-loss remedies have worked in the first six months of clinical trials, but then started losing effectiveness as the body built up resistance to the treatments. Long-term safety is also a huge concern. The U.S. Food and Drug Administration generally likes to see two years of safety data before making final approvals for obesity drugs , doctors said. Last August, the company initiated phase III trials of Rimonabant for obesity, studying 6,180 patients. The first study is a two-year North American trial of 2,800 patients comparing five-milligram and 20-milligram doses of Rimonabant to a placebo. The company is also conducting a two-year, 1,400-patient trial in Europe with the same standards. Alongside the trials, Sanofi is running two other 990-person studies looking at the effects of the drug in patients with diabetes and lipid problems. Weight loss from the Phase II trials was "in the same ballpark as medicines we've seen before, but you can't predict what's going to happen long term," said Lewis Aronne, director of the Comprehensive Weight Control Program at the Weill Cornell Medical Center in New York, which is participating in the latest human trials. Light Competition Currently there are only two obesity medicines approved for long-term use by the FDA -- Abbott Laboratories' Meridia and Roche Holding AG's Xenical. And they "aren't suitable for all patients" and don't produce staggering results, according to Kishore Gadde, director of Duke University Medical Center's Obesity Clinical Trials Program. Meridia shouldn't be taken by people with high blood pressure, and many patients stop taking Xenical -- which blocks fat absorption in the gut -- after dealing with the side effects, like diarrhea. The FDA approved Meridia, a drug that slows the body's dissipation of the brain chemical serotonin, as a treatment for obesity in 1997. The drug can increase the risk for heart attacks and stroke. It was removed from some European markets earlier this year after reports associating it with heart attacks, but European authorities recently concluded the drug remains useful. Sales of both Xenical and Meridia have failed to meet early expectations. It is likely that more than physical concerns are holding back revenue from these drugs . Insurers often balk at reimbursing patients for diet drugs , which they commonly group with other "lifestyle medicines," such as erectile dysfunction or baldness treatments. Without insurance coverage, the $90-to-$100-a-month price tag can be a bit heavy for some consumers to pay out of pocket. However, Americans desperately need to lose weight. The NIH estimates the prevalence of obesity in the U.S. may have increased by more than 75% in the past two decades. - --- MAP posted-by: Josh