Paul Rodgers Contributor 8/12/2014 @ 12:17PM
A simple injection that promises to replace heart transplants and other major cardiac surgery is being tested on humans with heart pumps for the first time.
The pioneering gene therapy will provide patients with a key enzyme that helps heart muscles to pump blood.
The technique – which has previously been successfully tried in animals and on human hearts in vitro, and is being tested concurrently on patients with less serious heart failure – is to be used by scientists from Imperial College London on patients with advanced heart failure at Harefield Hospital.
The replacement gene, Mydicar, developed by US biotech company Celladon, could help hundreds of thousands of patients a year, and make heart transplants and mechanical pumps obsolete. Some three million people in the US and Britain suffer from some degree of heart failure.
Lee Adams, the first patient in the trial to receive the gene therapy (Credit: Imperial)
“The best treatment currently available is a heart transplant, but the shortage of donor organs means that many patients will die on the waiting list,” said Dr Nick Banner, a consultant cardiologist at Harefield, who performed the first infusion on Lee Adams (pictured).
A fifth of those waiting for a transplant in Britain die before a suitable organ becomes available.
Heart disease is a progressive illness, often initiated by damage or disease, in which the heart becomes weaker as its cells malfunction.
Among its causes are high blood pressure, alcohol abuse, smoking, genetic defects and infections. Heart muscle cells can also be killed during heart attacks when their own blood supply is cut off.
“Heart failure devastates the lives of hundreds of thousands of people,” said Professor Peter Weissberg, medical director of the British Heart Foundation, which is funding the trial. “This cutting edge trial offers genuine hope of an effective treatment in the near future.”
The gene therapy involves injecting a benign virus with copies of the DNA for SERCA2a, an enzyme that helps heart muscles to contract by recycling calcium.
Two dozen patients, all of them currently fitted with mechanical pumps, are enrolled in the study, of whom 16 will get the gene. Biopsies of their heart muscles will be taken after six months to measure the gene’s spread and how well it is working.
“We will be using state-of-the-art methods to gain detailed information on how and where the gene therapy takes effect, which will potentially help us develop and improve the therapy,” said Professor Sian Harding, the head of the British Heart Foundation’s centre of regenerative medicine at Imperial.
Although the treatment involves the delivery of genes to the body’s cells, it is not correcting a genetic defect. “We are working much more downstream,” Professor Harding said. “No matter what the cause of the heart failure, the therapy should be equally beneficial.”
The researchers will also test to see whether the therapy works in patients with antibodies to the wild vaccine being used to deliver the gene.
“We have adapted the wild virus by removing the viral genes and replacing them with the treatment SERCA gene, so the virus acts like a biological courier to deliver our treatment gene,” said Dr Alex Lyon, the lead investigator from the National Heart & Lung Institute at Imperial.
“This particular virus is advantageous because it is not known to cause any human disease. However this means many people have been exposed to the virus without developing symptoms and therefore possess antibodies. If we demonstrate that the antibody does not block the delivery of gene therapy, many more patients could benefit.”