World and Nation

After Setbacks, Small Successes For Gene Therapy

Not long ago, gene therapy seemed troubled by insurmountable difficulties. After decades of hype and dashed hopes, many who once embraced the idea of correcting genetic disorders by giving people new genes all but gave up the idea.

But scientists say gene therapy may be on the edge of a resurgence. There were three recent, though small, successes — one involving children with a fatal brain disease, one with an eye disease that causes blindness and one with children who have a disease that destroys the immune system.

“We are ready to move,” said Dr. Luigi Naldini of the Institute for Gene Therapy at Vita-Salute San Raffaele in Milan.

Dr. Kenneth Cornetta, a gene therapy researcher at Indiana University and president of the American Society of Gene and Cell Therapy, added: “It’s exciting. The science gets better every year.”

But given the history of gene therapy, some, like Dr. Mark Kay, a gene therapy researcher at Stanford, were careful to avoid promising too much.

The field was dealt a blow when the first gene therapy success, reported six years ago, turned out to have a problem. Eighteen of 20 children with a rare genetic disease were cured, but then three of the children developed leukemia and one died of it. Researchers and gene therapy companies became skittish.

“I like to be really cautious,” Kay said. But now, he added, “there is a lot of reasonably cautious optimism.”

The latest encouraging news arises from a paper published Friday in the journal Science. An international team of researchers is reporting the successful treatment of two children with adrenoleukodystrophy, or ALD, in which the fatty insulation of nerve cells degenerates. A result is progressive brain damage and death two to five years after diagnosis. The disease was the focus of the movie Lorenzo’s Oil.

Scientists say they believe they avoided the cancer problem by using a different method to get genes into the children’s DNA. Two years have gone by, and the children are doing well.

The children were not cured, but their disease was arrested. And gene therapy was as good as the standard treatment, a bone marrow transplant.

In addition, a paper last month in the journal Lancet reported that a different method of gene therapy, which did not involve inserting a new gene into DNA, partly restored the sight of five children and seven adults with a rare congenital eye disease, Leber’s congenital amaurosis.