Two groups of researchers have independently corrected the biochemical defect that causes cystic fibrosis by inserting a healthy gene into diseased cells grown in the laboratory, a major step toward developing new therapies for the disease.
The findings, announced yesterday in the journals Cell and Nature, suggest it may be possible in a few years to cure the disease either by replacing the defective gene with a healthy one through gene therapy, by delivering an intact protein to the diseased cells or by developing new drugs.
"We're not talking decades, we're talking years, a few years," said Robert J. Beall, medical director of the Cystic Fibrosis Foundation. "We're very excited."
"These papers rank among the most important publications in the foundation's history," said Robert K. Dresing, foundation president.
Researchers found the genetic defect that causes the disease only a year ago. Yesterday's announcement indicates that the discovery has greatly accelerated the pace of research on the disease, which affects one in every 1,800 children, impairing breathing and cutting life short.
The possibility of gene therapy for the disorder has become even more intriguing because the first efforts at human gene therapy were begun just last week at the National Institutes of Health. Success of that treatment, or at the least demonstration that it does not have adverse side effects, is expected to pave the way for experiments with other proposed therapies, such as for cystic fibrosis.
The disease is marked by a buildup of mucus in the lungs and upper respiratory tract that impairs breathing and leaves the victims susceptible to respiratory infections.
Earlier this century, cystic fibrosis was uniformly fatal, killing most affected children during their first year of life. The development of antibiotics to control lung infections and the adoption of nutritional therapies have extended the median life span of CF patients to 26 years.
But there is currently no effective therapy for the disorder itself.
Of the two groups, one was headed by internist Dr. Michael J. Welsh of the University of Iowa College of Medicine and molecular biologist Alan E. Smith of Genzyme Corp. in Framingham, Mass., the second by geneticists Lap-Chee Tsui of the Hospital for Sick Children in Toronto and Dr. Francis Collins of the University of Michigan.
Now that researchers have identified the defective protein that causes the disease, it may be possible to use traditional pharmaceutical approaches to design drugs that would improve the protein's function. Such drugs might greatly ameliorate the symptoms of the disease.