Researchers say they've proven a long-held theory about heart disease: that lowering inflammation may be nearly as important as cutting cholesterol levels.
Anti-inflammatory injections could not only lower the risk of heart attacks but may slow the progression of cancer, a study has found, in what researchers say is the biggest breakthrough since the discovery of statins.
Heart attack survivors given injections of a targeted anti-inflammatory drug called canakinumab had fewer attacks in the future, the scientists found. Cancer deaths were also halved in those treated with the drug, which is normally used only for rare inflammatory conditions.
Professor Paul Ridker of Harvard Medical School, presenting his findings at the European Society of Cardiology congress in Barcelona this weekend, said the drugs opened up a "third front" in the war on heart disease.
''This plays beautifully into the whole idea of personalized medicine and trying to get the right drug to the right patient,'' he said.
Novartis, which makes the drug, said it would ask the Food and Drug Administration for permission to market the drug as a way to prevent heart attacks and would start further tests on its effect in lung cancer.
Statins are the mainstay drugs for heart attack prevention and work primarily by lowering cholesterol levels. But a quarter of people who have one heart attack will suffer another within five years despite taking statins regularly. It is believed this is because of unchecked inflammation within the heart's arteries.
The research team, led from Brigham and Women's hospital in Boston, tested whether targeting the inflammation with a potent anti-inflammatory agent would provide an extra benefit over statin treatment.
The researchers enrolled more than 10,000 patients who had had a heart attack and had a positive blood test for inflammation into the trial, known as the Cantos study. All patients received high doses of statins as well as either canakinumab or a placebo, both administered by injection every three months. The trial lasted for four years.
For patients who received the canakinumab injections the team reported a 15-per cent reduction in the risk of a cardiovascular event, including fatal and non-fatal heart attacks and strokes. Also, the need for expensive interventional procedures, such as bypass surgery and inserting stents, was cut by more than 30 per cent. There was no overall difference in death rates between patients on canakinumab and those given placebo injections, and the drug did not change cholesterol levels.
Prof Ridker, who led the research team, said, ''For the first time, we've been able to definitively show that lowering inflammation independent of cholesterol reduces cardiovascular risk.
''This has far-reaching implications. It tells us that by leveraging an entirely new way to treat patients – targeting inflammation – we may be able to significantly improve outcomes for certain very high-risk populations.''
The hospital said the reductions in risk were ''above and beyond'' those seen in patients who only took statins.
Ridker said the study showed that the use of anti-inflammatories was the next big breakthrough following the linkage of lifestyle issues and then statins.
''In my lifetime, I've gotten to see three broad eras of preventative cardiology,'' he said. ''In the first, we recognised the importance of diet, exercise and smoking cessation. In the second, we saw the tremendous value of lipid-lowering drugs such as statins. Now, we're cracking the door open on the third era. This is very exciting.''
But there were some downsides to the treatment. The researchers reported an increase in the chances of dying from a severe infection of about one for every 1,000 people treated, although this was offset by an unexpected halving of cancer deaths across all cancer types. In particular, the odds of succumbing to lung cancer were cut by over 75 per cent, for reasons the team do not yet understand.
The researchers are planning further trials to investigate canakinumab's potentially protective effect against cancer.