Gene therapy has never lived up to two decades of hype, but some intriguing new evidence for the technology emerged over the weekend at a medical meeting in Berlin. That was where San Diego-based Celladon unveiled results from a clinical trial—albeit a small one—that offers the first sign that gene therapy might help people suffering from heart failure.
Celladon hinted about what was coming in late April when it issued a vague statement saying that its gene therapy hit the main goal in a trial of 39 patients, demonstrating its superiority over a placebo. It turns out the trial, called “Cupid,” showed that a high dose of Celladon’s gene therapy offered a 50 percent lower risk of serious cardiovascular event like death, or a heart transplant, when compared with those who got a placebo. The Celladon treatment, called Mydicar, didn’t appear to cause any serious side effects, researchers said. Details were presented at the Heart Failure Association of the European Society of Cardiology.
“To see a signal like this in a small number of patients is promising,” says Barry Greenberg, a researcher at UC San Diego and an investigator on the study. “But you have to be realistic and say it is a small number of patients. It still needs to be re-produced in a larger study.”
That said, this data is sure to stir up hope in a long-struggling field. Gene therapy was hyped in the early 1990s as a cure-all for diseases that resisted conventional drug treatment. The idea is to deliver properly functioning copies of genes into cells where they can replace missing or faulty genes at the root cause of certain diseases. The field was plagued by safety concerns, and many companies abandoned the field over the past decade. After all those years, no gene therapy has won FDA approval.
Celladon, as I explained back in April, had a clear strategy on why it thought its approach would work. Older gene therapy techniques used common adenoviruses or retroviruses to deliver genes into cells, which often failed. Celladon sought out what it thought was a better delivery tool with adeno-associated virus technology from Seattle-based Targeted Genetics, which engineered the viruses to shuttle genes into cells without causing illness. Congestive heart failure was thought to be a promising field to study, partly because it’s a gravely serious illness that kills 300,000 people a year, who have few treatment options other than beta-blockers and diuretics. And Celladon’s therapy can be delivered via a direct infusion to the heart, and doesn’t need to circulate through the body-a distribution challenge that has plagued gene therapies before.