Scientists who have conducted clinical trials using gene therapy for cystic fibrosis (CF) patients have shown for the first time, after two decades of research, that the technique can significantly improve lung function.

Doctors and scientists from the Imperial College of London, Edinburgh and Oxford Universities, NHS Lothian, and the Royal Brompton & Harefield NHS Foundation Trust developed the gene therapy technique in 2001 while the Cystic Fibrosis Trust funded it.

The treatment, also called pGM169/GL67A, replaces the faulty gene responsible for the genetic lung disease, and through DNA molecules, a functional copy of the gene will be delivered to lung cells.

According to NHS UK, scientists previously tried to deliver the functional gene using a virus, but it failed because the defense mechanism of the lungs always blocked the entry of the virus.

Scientists then found a different way of gene introduction for the new trial. This time, the gene was enclosed in a "bubble of fat" which can reach the lungs by means of a nebulizer.

For the trial, the scientists gave either the gene therapy dose or a placebo to 140 randomly selected patients aged 12 and above who had CF, according to a report in The Lancet. 

Results of the trial, which lasted for one year, showed that patients who received the therapy showed a significant improvement in their lung function compared with those of the placebo group, according to Eric Alton, lead scientist and professor at Imperial College of London.

Explaining about the findings, Alton described them as "encouraging" but warned that the technique was not ready for clinical use due to inconsistent effects.

Alton said the team was now considering doing follow-up studies to determine if giving higher and more regular doses could offer better improvements, and find out if gene therapy, together with drug treatments, could have a greater effect.

Cystic fibrosis is considered as the most common lethal genetic disease in the world. The World Health Organization reports that incidence of the condition varies across all regions in the globe.

In the EU, one of 2,000 to 3,000 newborn babies will suffer from CF while in the U.S., the condition affects one in every 3,500 babies.