Gene therapy edges towards commercial reality

By Ben Hirschler, European Pharmaceuticals Correspondent

LONDON (Reuters) - Gene therapy may be about to become a commercial reality, 20 years after the first experiments with the ground-breaking medical technology.

But the tale of two biotech companies -- one British and one U.S. -- suggests a tricky road ahead.

On the one side, French authorities last week allowed an experimental gene medicine from Britain's Ark Therapeutics to be prescribed to certain patients with brain cancer, even though it is not approved for general use.

The news boosted hopes that the European Medicines Agency will clear Ark's drug Cerepro for sale across the European Union in the second half of 2009.

By contrast, U.S.-based Introgen Therapeutics -- which had been competing to get the first gene therapy approved in Western markets -- filed for bankruptcy in December, after a regulatory setback for its experimental cancer drug Advexin.

The last two decades have seen more than 1,470 clinical trials involving gene therapy, two-thirds of them aimed at cancer, according to the Journal of Gene Medicine.

But the only drug to get to market so far has been one for head and neck cancer from Shenzhen SiBiono GeneTech, which was approved in China in 2003 on data that most analysts do not believe would have supported a Western green light.

Some of the other U.S. and European companies in the space include Genzyme, Targeted Genetics, GenVec, Neurologix, Amsterdam Molecular Therapeutics and Oxford BioMedica.

BUBBLE BOY DISEASE

The idea of using genes to treat disease gained credibility in 1990, when the world's first clinical tests showed early success against a rare condition caused by faulty genes, called severe combined immunodeficiency (SCID).

People with SCID -- also known as "bubble boy disease" -- cannot cope with infections and usually die in childhood.

The field then suffered a major setback when an Arizona teenager died in a gene therapy experiment in 1999 gene and two French boys with SCID developed leukaemia in 2002.

More recently, though, doctors have made encouraging advances.

Last year, two separate academic teams reported success in using gene therapy for a type of inherited blindness call Leber congenital amaurosis.

And last month an extended follow-up study of SCID children concluded that eight of 10 treated seemed to have been cured, leading the New England Journal of Medicine to declare that gene therapy was "fulfilling its promise."