Drug hope for killer lung disease

A cheap antibiotic can overcome one of the genetic flaws that can lead to cystic fibrosis, say experts.

However, it will not help the majority of UK patients diagnosed with the killer lung condition.

In a small percentage of cases, a key lung cell protein is left half-completed because a mutated gene halts the production process.

However, the drug gentamycin helps the cell "skip" this gene and finish making the protein, alleviating the condition.

Pharmaceutical companies are scrambling to make new versions of the drug which might be able to make an impact in other conditions caused by a similar fault.

Some cases of muscular dystrophy could be checked, they believe, if their work is successful.

Cheap and effective

Gentamycin is already used by some cystic fibrosis clinics as an ingredient in a nebulised inhaler.

It appears to work on conditions where there is a fault called a "premature stop mutation" on an important gene.

In the case of cystic fibrosis, the CFTR gene is important because without it, an excess of thick mucus builds up in the lungs, leading to a cycle of infection and scarring that contributes to long-term damage.

Normally, these stop signals are placed towards the end of a gene, and tell the cell's protein-making machinery when the protein they are constructing is complete.

However, in cystic fibrosis, the stop signal has arisen earlier in the gene's makeup, and the resulting protein is not complete, and cannot perform its function.

However, a component of gentamicin binds to part of this stop signal, and allows the machinery to carry on past, making the complete protein.

Nostril cure

A study published in the New England Journal of Medicine last week revealed how gentamicin applied to the nostrils of people with cystic fibrosis led to normal CTFR production from those tissues.

New Scientist magazine reports that drug company PTC Therapeutics is trying to develop a new form of gentamicin which is both more potent and carries fewer side-effects.

However, a UK cystic fibrosis expert said that relatively few people worldwide carry "premature stop" gene faults - their disease is caused by other types of fault.

Dr. Iolo Doull, from the University of Wales College of Medicine, told BBC News Online: "This research was carried out in Israel, which is unusual because a far higher proportion of Jewish CF patients carry these mutations.

"In the UK, it is probably fewer than 10 percent."

However, he said that while efforts to produce other forms of gene therapy to help cystic fibrosis patients were continuing, there were expectations that drugs would emerge which could tackle other types of gene mutations.

He said: "You might be able to give customised treatments depending on the genetic makeup of the patient."

Professor Duncan Geddes, from the Royal Brompton Hospital in London, said that setting up a clinical trial of gentamicin for cystic fibrosis was impractical due to the small number of patients involved.

However, he added: "Any new drug coming through for CF is welcome - it boosts the morale of the CF community."

Source: BBC News