Cautious Optimism about Limited Gene Therapy

Medical gene transfer has had more than its share of tragedies and disappointments. It's also been the subject of all too much exaggeration and hype.

So it's worth noting some recent signs that are both modest and tentatively hopeful:

• Two children with a progressive brain disease received a treatment that combines gene therapy with blood stem cell therapy; they were not cured but the disease was arrested, and the treatment is said to be as good as the standard bone-marrow transplant (which was not available for those patients).
• Patients suffering from a degenerative retinal disease improved with the injection of a gene that increases protein production. This is not classic gene therapy, since the added gene is not incorporated in DNA and therefore is not copied when cells divide; retinal cells rarely do divide, however, and the treatment works, so long as the disease is not far advanced.
• Muscle mass increased in monkeys after the injection of a gene that inhibits myostatin, which breaks down muscle; researchers caution that "these animals did not have a degenerative muscle disease, and so our findings may not translate successfully to clinically effective treatments for such diseases."
• Earlier this year, it was reported that patients with an immunological disorder were successfully treated, albeit by a similar method to that associated with leukemia in X-SCID patients; it's unclear why it worked better this time.
• The Phase 1 study of a gene therapy treatment for Alzheimer's will soon transition into a Phase 2 clinical trial.

These are, as Gina Kolata pointed out in the New York Times, "small successes." It's a bit early to call them a "comeback" but that's exactly how they were hailed in Science, and the Los Angeles Times has been almost as enthusiastic. Researchers, however, seem to be proceeding cautiously, with limited but achievable goals -- aware that hype can overwhelm hope.

Previously on Biopolitical Times:

• Jesse Gelsinger: Ten Years Later
• Modified Marmoset in the Media
• "A Conspiracy of Hype"
• Gene Therapy's Tragedy: A Lesson for Stem Cell Research?