SHOULD smokers be offered a drug that prevents some of the physical damage to their lungs?
A Californian company is developing just such a treatment, but critics point out that it will not prevent cancer or damage to the rest of the body. They say drugs like this would discourage smokers from quitting by giving them a false sense of security.
Smoke irritates lung tissue, attracting immune cells such as macrophages and neutrophils that spit out destructive enzymes. These enzymes, which include matrix metalloproteases (MMPs), cut up structural proteins in lung tissue and destroy its elasticity, leading to serious breathing problems such as emphysema.
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Biotech company Arriva Pharmaceuticals has now created a drug known as GM6001 that halts the damage by blocking MMPs. Mice exposed to cigarette smoke for six months suffer 96 per cent less lung damage if they breathe in a daily dose of GM6001, the researchers will tell a meeting of the European Respiratory Society in Vienna, Austria, this week. Arriva鈥檚 chief scientific officer, Philip Barr, says he is already talking to collaborators about conducting a clinical trial.
Arriva is not alone. Some other companies are also working on their own versions of MMP inhibitors. And Raymond Bergan at Northwestern University in Illinois has already concluded a trial to determine whether another drug, oltipraz, can protect smokers against cancer. The drug stimulates the body to produce an enzyme that destroys carcinogens (快猫短视频, 7 April 2001, p 4). The participants suffered no serious side effects, he says, and his team is now analysing cell samples from the volunteers to see if oltipraz really does prevent cancerous changes.
But even if drugs such as GM6001 and oltipraz were proven to work and were taken together, they would not prevent all the dangerous effects of smoking. For instance, smoking raises heart rate and blood pressure, and helps clog up arteries, all of which increase the risk of heart attacks and strokes. And about 90 per cent of cases of peripheral vascular disease, which can lead to amputation of one or both legs, are caused by smoking.
The development of such drugs is not defensible, says Alfred Munzer of Washington Adventist Hospital in Takoma Park, Maryland, the former president of the American Lung Association. 鈥淎ny treatment will be of limited benefit, as smoking causes so many health problems,鈥� he says. 鈥淎nd it detracts from what smokers really need to do, which is stop smoking.鈥�
鈥淚 don鈥檛 smoke,鈥� responds Barr. 鈥淏ut I understand there are people who just can鈥檛 stop. Our drug will help these people.鈥�
Worldwide smoking is still on the rise. Small falls in the number of people smoking in western countries have been eclipsed by the number taking up the evil weed in developing countries.
Most harm reduction strategies have focused on trying to produce safer ways to deliver nicotine. The approaches include improved filters, ways of treating tobacco to reduce carcinogens, novel forms of cigarettes that do not produce smoke and various forms of tobacco designed to be popped into the mouth rather than smoked (快猫短视频, 10 November 2001, p 28).