Friday, December 14, 2012

Drug company kills off another cholesterol-modifying drug - Briffa

Drug company kills of another cholesterol-modifying drug
I rarely meet someone who has not heard of cholesterol and does not believe it to be a largely dangerous substance. And increasing number of people seem to be aware of the conventional wisdom regarding the different forms of cholesterol, specifically low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C). Actually, these names are a bit misleading, as these particles are not cholesterol (though they do contain cholesterol). But, anyway, the conventional wisdom is that LDL-C dumps cholesterol on the inside of our arteries while HDL-C clears cholesterol. As a result, LDL-C and HDL-C are often dubbed ‘bad-’ and ‘good-’ cholesterol.

The most commonly prescribed cholesterol drugs are known as statins, and their main mechanism of action is to lower LDL-C levels. However, other types of cholesterol-modifying drugs exist, including a relatively new class known as cholesterylester transfer protein inhibitors (CEPT inhibitors), which the conversion of supposedly healthy HDL-C into supposedly unhealthy LDL-C. If you believe the conventional wisdom on cholesterol (I don’t), then this should translate into benefits for health with regard cardiovascular disease (e.g. heart disease and stroke).

All this theory is meaningless, however. The only important thing is not the effect drugs (or anything else) have on cholesterol levels, it’s the impact they have on health. Some years back the drug company Pfizer spent in the region of $800 million developing a CEPT inhibitor by the name of torcetrapib. It had ‘positive’ effects on LDL-C and HDL-C levels, but also turned out to kill people. Pfizer promptly and quite rightly ceased development of the drug.

The crashing failure of torcetrapib has not stopped other drug companies seeking to find a commercially viable CEPT inhibitor of their own. More recently, drug company Roche invested in the development of a drug known as dalcetrapib. However, in the middle of this year Roche abandoned plans for further development, and a recently-published study shows us why [1].

In this study, published in the New England Journal of Medicine, almost 16,000 patients who had suffered from ‘acute coronary syndrome’ (e.g. angina or heart attack) were treated with dalcetrapib or placebo for an average of about two and a half years.

These are just the sort of patients one would expect to benefit most from an intervention because, as a group, they would generally be at high risk of future problems. Also, the number of subjects here is huge, and therefore more than big enough to detect any real benefit the drug may have.

The researchers assessed the effects of dalcetrapib using a ‘composite endpoint’ – which essentially means lumping several outcomes together. The composite outcome included death from heart disease, non-fatal heart attack, ischemic stroke (strokes due to blockage of blood vessels rather than bleeding), unstable angina (angina that can come on at rest), and cardiac arrest with resuscitation. The use of composite endpoints ups the odds that a ‘statistically significant’ benefit for a drug will be found (compared to when only one single outcome is chosen).

Biochemical analysis revealed that dalcetrapib did, as expected, have considerable HDL-boosting effect. But the study showed that this drug had no benefits for health at all.

Another interesting thing about the study was that dalcetrapib was found to increase markers of inflammation – a process which is believed to play a key part on the development of heart disease and stroke.

This study was originally designed to run for longer but was terminated early once these results were in. Early termination of studies is known to generally inflate the benefits of drugs and downplay their risks. Who knows what may have happened if they’d continued.

Of course you’re unlikely to hear about the dalcetrapib study because it wasn’t announced with the blaze of publicity usually afforded to more ‘positive’ studies about cholesterol-reducing drugs. But this is often the way with cholesterol-related research in particular: positive results are spun in a way which gives medication seeming miraculous properties, while negative results and inconvenient truths are swept under the carpet.

1. Schwartz GG, et al. Effects of Dalcetrapib in Patients with a Recent Acute Coronary Syndrome. N Engl J Med 29 November 2012 (epub)
Read the complete article here.

No comments:

Post a Comment

I appreciate appropriate comments but reserve the right to publish those with credible, verifiable, significant information to contribute to the topic at hand. I will not post comments with commercial content nor those containing personal attacks. Thank You.