Sunday, May 31, 2009

New treatments for cystic fibrosis may help others with genetic disorders

An abstract of the article in The New Yorker:

ANNALS OF MEDICINE about the development of new treatments for cystic fibrosis and how those treatments might be applied to other diseases. Cystic fibrosis is the most common fatal genetic disorder in North America among Caucasians; some thirty thousand Americans have the disease, and about ten million Americans are silent carriers. Describes the symptoms of those who suffer from cystic fibrosis, including the blockage of the gastrointestinal tract and reduction of lung function.

Tells about Chrissy Falletti, who has cystic fibrosis and participated in a trial of an experimental oral drug produced by Vertex Pharmaceuticals. After twenty-eight days on the medication, her lung function had increased by eighteen per cent over all. Her lung function began to decline within a week of the trial’s end. Vertex is launching a long-term, placebo-controlled trial that could lead to F.D.A. approval this year.

And while the drug targets a form of cystic fibrosis that occurs only in four per cent of patients, the fact that similar drugs are being developed by Vertex and other companies seems to signal a new treatment paradigm. Briefly gives the history of cystic-fibrosis treatment from its identification by Dr. Dorothy Hansine Andersen in 1935, to the discovery in 1985 that the cystic-fibrosis gene was situated on the seventh chromosome.

In 1989, researchers identified the gene and determined its function. The discovery set off a wave of euphoria, with many people convinced that cystic fibrosis would soon be cured. Yet, despite successes in the laboratory, patients had an immune reaction to the procedure, rejecting the delivery system that held the normal gene. Discusses the work of the Cystic Fibrosis Foundation, which is headed by Dr. Robert Beall, and its funding of research for the disease, including the use of automated systems to help produce a drug that could be taken orally and would work throughout the body to restore the functioning of diseased organs.

Discusses the different categories of mutations in the cystic-fibrosis gene and the “molecular origami” undertaken by scientists in their attempt to address these categories. Tells about the development of other cystic fibrosis drugs, including one by PTC Therapeutics, which reduced the rate of coughing in patients in a study in Israel. These drugs may have ramifications beyond cystic fibrosis. The drug produced by PTC Therapeutics could be applied to a wide number of genetic diseases.

Although the treatment of genetic disorders has long been considered too small a market for most pharmaceutical companies, an increasing number of biotech firms have found that genetic research can be used in broader ways than anticipated. All of the physicians and scientists the writer spoke with emphasized the many unknown variables, but for the first time, there is convincing evidence that the underlying defect in cystic fibrosis can be corrected.