Shot in the arm for fight against heart attacks: The fortnightly jab that could unclog your arteries
21:43 GMT, 7 May 2012
Sharp research: A new drug administered as a fortnightly jab could cut 'bad' cholesterol levels, say scientists
A fortnightly jab that slashes levels of ‘bad’ cholesterol could dramatically reduce the death toll from heart attacks and strokes.
The injection, given either in the arm or the stomach, has been shown to wipe out nearly three-quarters of the body’s low-density lipoprotein (LDL) — the harmful form of cholesterol that leads to clogged arteries and heart disease.
If the jab’s early success is borne out in further trials, experts say it could have a major impact on the treatment of high cholesterol.
Heart disease is Britain’s biggest killer. Around 270,000 people a year suffer a heart attack, and nearly one in three die before they reach hospital. Fatty diets, lack of exercise and smoking are all key risk factors.
Cholesterol is a type of fat produced by the liver that is essential to help the body produce hormones, absorb vitamin D and make bile to digest foods.
It is transported in the blood by tiny ‘couriers’ called lipoproteins. However, one of these lipoproteins, called low-density lipoprotein (LDL), is labelled ‘bad’ as it carries cholesterol away from the liver and dumps it in major blood vessels, where it can cause a life-threatening blockage.
High-density lipoprotein, or HDL, is known as ‘good’ as this compound has the job of transporting cholesterol back to the liver to be safely disposed of.
Current guidelines in the UK recommend keeping total cholesterol below 5mmols per litre (a measurement of how much fat there is in each litre of blood), with LDL accounting for no more than 3 mmols/litre.
The main weapon in the battle against cholesterol has been statins, which are taken by seven million people in Britain.
Although statins are effective for most people, an estimated 20 per cent of patients with excessive LDL levels are classed as resistant to the drugs and see little or no reduction in their blood fat levels.
Doctors are unsure why this occurs, but speculate it may be due to the patients’ genetic make-up. The new drug comes from a class of medicines known as monoclonal antibodies. This kind of drug is already being used to treat cancer and tends to work by targeting a specific protein found on the surface of a cell.
In the case of cholesterol, the drug is formulated to work on a protein known as PCSK9. Ten years ago, scientists discovered this protein appeared to increase the amount of bad cholesterol in the bloodstream.
The theory is that the protein stops the liver removing LDL molecules from the bloodstream, and as a result this ‘bad’ cholesterol continues floating around the body, clogging up arteries.
The new drug comes from a class of medicines known as monoclonal antibodies
The goal was to come up with a drug that would stop the blocking actions of this protein.
Now two drug companies, Sanofi U.S. and Regeneron Pharmaceuticals, both based in America, have teamed up to develop a drug that comes closer to wiping out excess LDL than any other treatment.
To test it, doctors at a private medical research company called National Clinical Research, based in Virginia, recruited 183 patients who were already being treated with medium doses of statins of 40 mg a day yet still had high LDL readings.
The patients were split into several groups. One got a dummy jab every few weeks, the rest got various doses of the new drug at different intervals over a 12-week period.
The best results came in the group that was given a 150mg jab every two weeks, where the decline in LDL levels averaged 72 per cent. In the placebo group, LDL levels fell just 5 per cent.
The experimental drug, code-named REGN727, is still in the early stages of development and is unlikely to be available for use for at least two to three years.
Commenting on the research, Professor Keith Fox, a cardiologist at the University of Edinburgh, said the results of early studies on the cholesterol jab were ‘very exciting’.
‘Although statins work for the vast majority of people, there are some for whom cholesterol remains high,’ he says. ‘If this new treatment can help these people, that is a potentially exciting development, but it’s still very early days.’