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| Archive : Winter 2007 |
RADICAL VISION:
A cocktail of cardiovascular drugs // Recommended for everyone over 55 // No prescription necessary // No need for a doctor’s oversight // The brainchild of overly ambitious would-be pioneers, or truly
the world’s next wonder drug?
The Polypill [page 3]
 By Rachael Moeller Gorman |
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After reviewing the impact of these drugs alone and in combination, Wald and Law found that combining two or more produced a greater reduction in blood pressure than giving just one, while cutting the normal dose in half appeared to provide almost as great a benefit (80%) as the drugs at full strength. Extrapolating from the results of all the studies, they hypothesized that if everyone over age 55 took a combination of three drugs at half the standard dose, there would be a 63% lessening of stroke risk and a 46% reduction in heart disease for people between the ages of 60 and 69.
Wald and Law performed a similar analysis of cholesterol-lowering drugs, examining 164 short-term, randomized, placebo-controlled trials on six statins: rosuvastatin, atorvastatin, lovastatin, simvastatin, pravastatin and fluvastatin. Those drugs reduce cholesterol by inhibiting the enzyme HMG-CoA reductase, thus slowing cholesterol production and increasing the rate at which it is cleared from the bloodstream. The team also examined 58 randomized trials of cholesterol reduction by any means and nine cohort studies (a type of observational study—not as rigorous as randomized, controlled trials), and they studied the effect of aspirin, which lowers risk of clots. Looking at 15 randomized trials, they concluded that low-dose aspirin reduces heart attacks by 32% and strokes by 16%.
After also considering side effects, Wald and Law proposed their Polypill formulation: a statin, the three blood pressure drugs at half dose, and low-dose aspirin. Such a pill, they calculated, may cause side effects in 8% to 15% of people—not a trivial risk, and mostly a result of aspirin. Certain people, such as those with asthma or those who are intolerant of aspirin, might experience more severe problems. Still, adding together the risk reductions each component part could be expected to produce, they projected that the Polypill could enable one-third of the population to live an average 11 to 12 years longer.
Although it’s far from certain that would really happen, a few observational studies have looked at the long-term benefits of combining some of the components proposed for the Polypill, and the results seem to support Wald and Law’s claims. In a German study, patients who had a heart attack and later took four different medications—aspirin, a beta-blocker, an ACE inhibitor and a statin—were significantly more likely to survive one year than those who took zero, one or two medicines. Similarly, a British study found that a combination of statins, aspirin and beta-blockers reduced mortality more than any drug given by itself or with one other medication.
These are trials of secondary prevention, in people who are already sick, rather than the primary prevention that Wald and Law would like to see, and the trials are also observational studies, rather than the more rigorous randomized, controlled trials. Still, the Polypill’s components have compiled years of effective treatment when used singly, and these studies add weight to the idea that a combination might produce even better results.
Several secondary prevention trials of the Polypill may soon begin validating the idea. In Australia and New Zealand, more than 1,000 people with cardiovascular disease will either be given a Polypill (in these trials, it consists of two blood pressure drugs, a statin and aspirin) or continue to be treated as usual by their doctors. One aim is to gauge whether they are more likely to stick to the drug regimen when the drugs are all in one pill. Another goal, cited in a report by a working group at the U.S. Centers for Disease Control and Prevention convened in early 2005 to discuss the Polypill, is whether the combination of drugs will prove to be additive (1+1=2), subadditive (1+1>1 but <2), antagonistic (1+1<1) or synergistic (1+1>2).
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Illustrations by Christoph Niemann |
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