In his weekly journal review, Dr. Richard Lehman points out another classic example of how you can’t jump to conclusions just because a drug has an impact on a surrogate outcome. It’s the big stuff we should focus on – not the surrogates. He writes:
Niacin is an abundant natural B vitamin, which lowers bad cholesterol and raises good cholesterol. What’s not to like? Well, niacin, unfortunately. In doses that make any difference to lipid levels, it is very likely to make you feel sick, get flushes and/or rashes, and/or feel muscle pains. So Merck decided to market it in combination with laropripant, a prostaglandin antagonist that is meant to combat its unpleasant effects. Even so, a third of people who were recruited to the present trial could not continue past the run-in phase with the active combination. And now that the full results are out, we have confirmation that this dual agent definitely does not offer any cardioprotection despite its “favourable” effect on lipids. Worse still it causes bleeding, raises blood sugar, and shows a tendency to increase mortality in those who can tolerate taking it for three years. The Clinical Trials Support Unit (CTSU) at Oxford did a great job of running this trial with funding from Merck, following its usual rules of independence. In doing so, it provides a great illustration of the fact that lipid fractions are very unreliable surrogates for cardiovascular outcomes. But we knew that already, and it seems a great pity to me that many superb researchers were tied down for so long on a project that has made such a small contribution to clinical knowledge, whatever it may have contributed to the funds of CTSU.
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