LONDON - Doctors who gave children with cystic fibrosis a replacement copy of a defective gene say it appeared to slow the expected decline of some patients' lungs, but called the results "modest" and say there must be major improvements before offering the treatment more widely.

Cystic fibrosis is an inherited condition that fills the lungs with mucus, making people susceptible to infections that can eventually destroy the lungs; the average life expectancy is about 37 years. After scientists identified the genetic sequence that causes cystic fibrosis in 1989, many experts hoped the disease could be cured by replacing the problem gene. But before the new study, all attempts at such gene therapy — where a normal version of the faulty gene is given to patients — failed to show a benefit.

In the new study, doctors in London and Edinburgh gave 78 children with cystic fibrosis a monthly dose of gene therapy using a special inhaler in the hospital while 62 others got a placebo treatment. All of the participants were older than 12.

Children who got the gene therapy showed about a four per cent better lung function compared to those who got the placebo. But doctors said the perceived benefit was just a stabilization of the lungs from deteriorating further, rather than an actual improvement. The results could also have been simply due to chance. Both groups were followed for one year.

"Our only hope was that some of the patients, on some occasions, might see some benefit," said Dr. Eric Alton of Imperial College London, the study's lead author. The research was published online Thursday in the journal, Lancet Respiratory Medicine. Alton said that while some children reported feeling better, others didn't feel any difference.

Some experts said the trial could spur related gene therapy studies.

"This is a long-term problem and the solution is going to take time," said Dr. William Skach, vice-president for research at the Cystic Fibrosis Foundation in the U.S., who was not involved in the study.

Skach described the results as encouraging, but said scientists need to figure out how to improve delivery of the needed gene to patients to get better results.

"That could translate into extended lives for patients," he said. "If we really want to impact on the disease in a major way, we need to think about how to do this more effectively."

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Online:

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