Are we edging closer towards lowering the risk of recurring heart attacks? Scientists definitely think so. In what has been described as the biggest advance since the discovery of statins, a study has shown that anti-inflammatory injections could lower the incidence of recurring heart attacks in heart attack survivors. Furthermore, these injections have been suggested to also slow the progression of cancer.
It has been discovered that heart attack survivors who were administered injections of a targeted anti-inflammatory drug called canakinumab had a lower risk of such attacks in the future. With this particular drug as well, the incidence of cancer deaths were also reduced to less that fifty percent.
Canakinumab is not normally prescribed for this purpose; its function normally lies in the use for rare inflammatory condition. Instead, the current drugs for the prevention of heart attacks are statins. The main method in which statins prevent heart attacks from recurring is by lowering cholesterol levels. Despite this, statin users who regularly take the drug have a one in four chance of suffering another heart attack within half a decade. While the cause for this is unknown, and research has been done on heart attacks and statins, the current line of thinking is that inflammation within the heart’s arteries are the cause of this recurrence.
The research team followed over 10,000 patients and were led from Brigham and Women’s hospital in Boston. One of the hypotheses tested was whether targeting the inflammation with a potent anti-inflammatory agent would provide an extra benefit over statin treatment. In other words, the trial aimed to see if statins combined with canakinumab would be better than just statins alone. The 10,000 patients who had had a heart attack and had all received a positive blood test for inflammation into the trial. In addition to the doses of statins, patients also received either canakinumab or a placebo, both administered by injection every three months. The trial, also known as the Cantos study, lasted for four years.
For the first group – patients who had received the canakinumab injections – the results demonstrated that there had been a 15% reduction in the risk of a cardiovascular event; this means that the risks of heart attacks, either fatal or non-fatal, and strokes had been reduced. But the benefits of canakinumab did not merely end there. The need for expensive interventional procedures, such as surgery such as bypass surgery, or the insertion of stents, was reduced by over three-tenths. The drug did not, however, change cholesterol levels, meaning that it must still be used alongside statins, and the use of statins as cholesterol limiters will still continue to remain so. There was also no significant statistical difference in the number of death rates between patients who had received canakinumab and those who had been given placebo injections.
Dr Paul Ridker, who led the research team, said the study did “usher in a new era of therapeutics”.
This study is the first incidence where scientists have been able to show conclusively that the risk of cardiovascular risk is reduced when inflammation independent of cholesterol is lowered. Why the results have been considered ground-breaking is due to the insight that they have provided; there could be an entirely new way to treat patients and significantly improve health outcomes through the targeting of inflammation, jointly with the lowering of cholesterol. The statistical benefits for patients who took canakinumab were described as being “above and beyond” those seen in patients who only took statins.
Dr Ridker also mentioned that 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 despite the promising results of the treatment, it was not without its negatives. The researchers reported that there was a rise in the potential chance of dying from a severe infection for about a tenth of a percentage point, although this increase was counterbalanced by decrease by over 50% of cancer deaths across all cancer types. The most promising cancer reduction rates were seen in the case of lung cancer. The odds of dying from lung cancer, with the use of canakinumab, were reduced by over three quarters. There was no scope within this study to investigate that further, although subsequent trials to investigate canakinumab’s effect against cancer are being considered.
Prof Martin Bennett, a cardiologist from Cambridge, had no involvement in the study, and while he said the trial results were a promising insight in understanding the occurrence of heart attacks, he expressed concerns both about the side effects, whether the high cost of the drug would pass the Quality Adjusted Life Years (QALY) test that the NHS administers to determining cost effectiveness of drugs, and also the fact that there were no significantly lesser incidences of deaths between those prescribed canakinumab and those who had received the placebo.
“Treatment of UK patients is unlikely to change very much as a result of this trial, but the results do support investigation of other drugs that inhibit inflammation for cardiovascular disease, and the use of this drug in cancer,” he said. In other words, despite the results of the study and what we can glean from them, he believes statins will still remain the mainstay of recurrent heart attack prevention.
Prof Jeremy Pearson, who is the associate medical director at the British Heart Foundation, showed more positive belief about the trial and the possibilities of it opening the doors to new types of treatment for heart attacks.
He mentioned that heart attacks account for a high number of hospitalisations every year. The figure is thought to be close to two hundred thousand people each year in the United Kingdom. He further explained that the use of cholesterol-lowering drugs like statins, when prescribed to these people to reduce their risk of another heart attack, does save lives, but the reduction of high cholesterol rates as a mere medical focus alone is not always a measure that effectively deals with the whole of the problem.
He added that one could be forgiven in feeling a flutter of excitement when it came to these trial results, which have been eagerly awaited by the medical community. The confirmation of previous medical hunches that the continual inflammation is a significant contributor to the risk of heart disease, and that the intent to reduce it could help save lives, is a significant way forward towards the treatment of heart attack patients.
This research into canakinumab is one of many that have been conducted into heart attack prevention. We should be cautious about its possible side effects; aspirin, for example, has been shown to cause bleeding when prescribed to heart attack patients. It has also been suggested that beta blockers for heart attack patients, on the other hand, do not have the ascribed health benefit. Furthermore, if the drug does end up prescribed to heart attack sufferers, what are the side effects when taken for the long term?
Could we possibly see canakinumab being prescribed as a matter of course for heart attack patients to prevent a recurrent? The answer perhaps lies not with whether or not the drug has benefit – it has already proven this in some areas – but whether the side effects can be mitigated. More importantly, the issue of cost will probably determine its future. If the cost of canakinumab could be lowered, so that its prescription to the over two hundred thousand heart attack sufferers per year would not be a significant burden on the financial limitations on the health service, then we could see it being prescribed as a matter of course. If not, then we may have to wait for a less expensive substitute to hit the market. And while it is somewhat disheartening that medical intervention in recent times is more geared not towards finding medicine that works, but medicine that is cost effective, the promise of canakinumab nevertheless is a positive health step.