'Spray' gene therapy trial for cystic fibrosis

UK researchers are to begin a large scale trial to test the effectiveness of a new gene therapy treatment for cystic fibrosis (CF). The treatment, which has shown promise in animal studies and preliminary human trials, uses a nebuliser to deliver the gene in spray form. Results from the £20 million trial, most of which is being funded by the Cystic Fibrosis Trust, should be available by 2010. If it succeeds, the treatment could provide new hope for families affected by CF - including UK chancellor Gordon Brown and his wife Sarah, whose four month old son James Fraser was recently diagnosed with the condition.

CF mainly affects the lungs, where thick mucus builds up causing repeated infections and breathing difficulties, and the pancreas, where blockages cause digestive problems. People with CF cannot control the levels of salt and water in their body cells properly, so their body fluids are thicker than usual. In 1989, researchers discovered that people with CF have no working version of the CFTR gene (cystic fibrosis transmembrane conductance regulator), which usually makes a protein that controls salt levels.

Since the discovery of the CFTR gene, many researchers have been trying to develop a gene therapy treatment for CF, based on delivering a working copy of the gene to the affected tissues. However, one of the challenges facing gene therapy researchers is getting enough of the replacement gene into the cells, and achieving a permanent effect. In the latest trial, the researchers will use tiny fatty spheres called liposomes to deliver a working copy of the gene. By taking this approach, they will avoid any potentially harmful side effects that could be triggered by methods that use viruses to deliver therapeutic genes.

The main trial will begin in 2008, but a preliminary investigation into the best ways to measure lung function and disease is set to start next spring, at the Brompton Hospital in London and Western General Hospital, Edinburgh. Lead researcher Professor Eric Alton said that what makes the trial 'very novel' is that the team will be testing for signs of clinical improvement. 'In other words, what's the level of inflammation in your lungs - has that reduced? The number of bacteria in your lungs - has that reduced? The picture on the CT scan of your lungs - has that improved in any way', he added.

The treatment will only be used for CF patients aged 12 and over. When asked at a press briefing if an effective therapy would be available by the time Mr Brown's son reaches that age, Professor Alton replied that 'I think it's very likely we will have some form of gene therapy that will be able to stabilise or prevent some of the symptoms', adding 'I would be disappointed if after this effort we don't have something in this timescale'. However, he cautioned against making predictions, saying there was still a chance the therapy would not succeed.

Rosie Barnes, the chief executive of the CF Trust, said: 'Although for new families like the Browns we always want to offer hope and optimism for the future, without this research this remains a very fearsome disease which takes a huge toll on the lives of all those it affects'. She continued: 'I'm optimistic. We've harnessed the best scientific talent in the UK, and they're very focused. If anybody's able to do it, they are. My view is we've got to keep trying'.