The Pharmaceutical Journal
Vol 274 No 7346 p483
23 April 2005

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Antibiotics do not cut CAD events

Using antibiotics to eradicate bacteria from the arterial plaque of patients with coronary artery disease does not reduce the risk of secondary cardiac events, results from two new clinical trials indicate.

Earlier studies have shown that Chlamydia pneumoniae is associated with increased risk of atherosclerosis and has been detected in atherosclerotic lesions. This, the authors of the new studies explain, has raised the possibility that antibiotic treatment might have a favourable effect on the course of coronary heart disease.

In the first study, known as ACES (azithromycin and coronary events study), Thomas Grayston, of the University of Washington, Seattle, and colleagues assigned 4,012 patients with stable coronary artery disease to either 600mg azithromycin or placebo weekly for one year. After an average follow-up of 3.9 years there was no significant reduction in cardiac events among those patients given active drug compared with those given placebo. The lack of effect was observed for all participants regardless of age, gender, smoking status or presence of C pneumoniae antibody (New England Journal of Medicine 2005;352:1637).

These findings are backed up by data from the second trial, known as PROVE-IT (pravastatin or atorvastatin evaluation and infection therapy), which tested gatifloxacin — a new fluoroquinolone. A total of 4,162 patients admitted to hospital with acute coronary syndrome were given either 400mg of the antibiotic or placebo (given as a 10-day course every month throughout the trial). After an average follow-up of two years, the researchers could not detect a benefit from gatifloxacin treatment — no reduction in cardiac events was observed.

The PROVE-IT researchers hypothesise that C pneumoniae may be a cause of early atherosclerosis. “It is possible that infection with C pneumoniae is part of the initiation of atherosclerosis in the early decades of life but not an active part of the progression of disease later, when patients have established coronary artery disease,” they say (ibid, p1646).