Cancer drug gives hope in treating heart attacks

Cambridge researchers have found a drug used to treat cancer could help with heart attack recovery.

Funded by the British Heart Foundation, NIHR Cambridge BRC and supported by the NIHR Cambridge Clinical Research Facility, researchers from Cambridge University Hospitals and the University of Cambridge found that a low dose of the cancer drug, aldesleukin, could harness the power of the immune system to improve recovery after a heart attack. Published in the New England Journal of Medicine – Evidence, researchers have said it has the potential to become the first treatment of its kind available for patients.

A heart attack is where the supply of blood is blocked to the heart, it can be life-threatening, requiring urgent treatment as it could potentially cause serious damage to the heart.

When a heart attack occurs it triggers the body’s immune cells to rush to the damaged heart and surrounding blood vessels. However, instead of having a healing effect, this can cause further harm, increasing the risk of future heart attack, stroke, and heart failure. Right now, there are no treatments available to counter this damaging immune response.   

Cambridge researchers launched a 2a clinical trial at NIHR Cambridge Clinical Research Facility, where they tested aldesleukin, a drug used to treat cancer, to see if it could help the immune system and heart attack recovery.

High doses of aldesleukin stimulate the immune system to attack cancer cells. Researchers investigated whether using doses a thousand times lower than those used in cancer treatment could selectively target and boost anti-inflammatory cells in patients’ immune systems. 

They found that low doses could improve recovery after a heart attack by stopping the harmful feedback loop. Researchers will now carry out larger clinical trials, in the hope it could be used to treat patients within the next 5 years. 

Repurposing cancer medication

The study involved 16 patients admitted to hospital with a heart attack who were given one of two doses of aldesleukin or a placebo. The drug was injected under the skin in their abdomen once a day for five days, and they were then followed up again a week after they’d received the final dose of the drug. 

Researchers found patients that received aldesleukin had a significantly greater increase in the number of regulatory T cells, a type of white blood cell that calms inflammation, a week after their last dose of aldesleukin compared to those who received a placebo. 

Further analysis revealed that not only were the numbers of regulatory T cells increasing, but the cells themselves had features that suggested that they were also becoming more anti-inflammatory.  

Low doses of aldesleukin also decreased the levels of other types of immune cells that can have damaging effects on inflammation and recovery after a heart attack. The team thinks this is another way that the drug could promote healing.

Researchers were encouraged with the results and are currently halfway through a larger clinical trial to investigate whether low doses of aldesleukin after a heart attack can reduce inflammation in patients’ blood vessels, which could potentially provide even more treatment to patients.    

Dr Tian Zhao, British Heart Foundation Clinical Lecturer in Cardiovascular Medicine at the University of Cambridge, said: “It’s only in the past decade that we’ve begun to understand the considerable role that the immune system plays in heart attack recovery. 

“In this study we’ve shown, for the first time, that low doses of aldesleukin given to heart attack patients can enhance the number of anti-inflammatory cells in the immune system. Previous research has suggested that this can reduce inflammation in blood vessels and improve heart healing. 

“Our ongoing study will give us the first signs of whether this is having clinical benefits for patients. We hope these results will bring us one step closer to the first treatment that can stop the damaging immune response that follows a heart attack.” 

Professor James Leiper, Associate Medical Director at the British Heart Foundation, said: “In the UK one person is admitted to hospital with a heart attack every five minutes. Thankfully, more people than ever are surviving heart attacks, but some will be left with long-term health problems such as heart failure. We urgently need new treatments that can help people to make a better recovery after a heart attack and reduce their risk of future ill health. 

“Treatments that can unlock the anti-inflammatory power of the immune system have the potential to become a new treatment option for heart attack patients. This research is an important step towards making this type of treatment a reality.” 

This research was also funded by the Medical Research Council.

Adapted from BHF press release