A biotech investor explains the hype over gene therapy

  • Gene therapy has garnered a lot of hype for its potential to cure rare diseases.
  • But what is it, and how is it different from traditional therapies?
  • We asked biotech investor Nina Kjellson to explain it to us.

Gene therapy has been in the news a lot of late as a potential cure for a variety of genetic diseases.

The biggest breakthrough involved a unanimous backing from U.S. Food and Drug Administration's advisory panel for a new gene therapy from Spark Therapeutics, intended to treat rare eye diseases. But what exactly is gene therapy, and does it deserve all that hype?

CNBC sat down with Canaan Venture Partners' biotech investor Nina Kjellson for a simple explanation of how it all works, and why she's excited about it. As Kjellson explains, in the most simple terms, gene therapy is a technique that uses genes to treat disease.

The first patients were tested about twenty-five years ago, but early trials were not uniformly successful. In one notable case, it led to the death of 18-year-old Jesse Gelsinger, who got an infusion of trillions of genetically engineered viruses into his liver.

Spark has seen some better results for its therapy, which treats a rare condition that causes a form of blindness that often starts in childhood.

Its treatment involves using a modified version of a virus to carry a healthy version of the gene into the retina. Think of it as a good copy of the gene.

The crazy part? Doctors will inject billions of these viruses — or "vectors" — into both of the patient's eyes to reach the cells where it's needed.

The FDA hasn't approved Spark's therapy just yet, but it usually follows the advice of the advisory committee.

A big obstacle remains — and that's price. The cost for each patient could be as high as $1 million, which insurance companies might decline to cover.

For Kjellson, these experimental therapies have a lot of promise as they could treat a wide variety of medical conditions, starting with genetic disorders caused by mutations in single genes.

It's still early days, but the hope is that gene therapy might someday replace drugs or surgery by fixing the problem at its root.