Genzyme Corp. said the Recombinant AdvisoryCommittee of the National Institutes of Health hasgranted approval for the first clinical study involvingaerosol administration to the lungs of a gene therapy forcystic fibrosis.
The FDA, which reviews RAC recommendations, mustapprove the protocol before the trials can begin.Genzyme, of Cambridge, Mass., said the studies aredesigned to test the safety of gene delivery to the lungs.
Forty cystic fibrosis patients at the New England MedicalCenter and Massachusetts General Hospital, both inBoston, will participate in the single dose trials.
Genzyme's gene therapy protocol uses an adenovirusvector, which includes portions of a disabled commoncold virus, to deliver a normal copy of the defective genelinked to cystic fibrosis. Some patients will inhale theadenovirus vector while others will have it dripped intotheir lungs with a bronchoscope.
Genzyme also is testing the adenovirus vector byadministering it into the nasal epithelium of cysticfibrosis patients. A pilot study in 1993 involveddelivering a normal cystic fibrosis gene to the epithelialcells of the nasal passages of three patients. Data from thetrial showed the treatment was safe and temporarilyeffective.
The cystic fibrosis transmembrane regulator (CFTR)gene, first identified in 1989, was determined to code fora protein that acts as an ion channel, regulating thetransport of chloride ions out of the cell.
If the CFTR gene is mutated, chloride ions, which carry anegative charge, are not transported, affecting themovement of other ions and, in turn, the distribution ofwater molecules. The result for cystic fibrosis patients isan accumulation of thick mucus in the lungs andrecurring respiratory infections.
Other cystic fibrosis clinical studies involving adenovirusvectors include trials conducted by Genetic Therapy Inc.,of Gaithersburg, Md.; GenVec Inc., of Rockville, Md.;the New York Hospital-Cornell Medical Center in NewYork; the University of Pennsylvania Institute for GeneTherapy in Philadelphia; and the Cystic Fibrosis Center atthe University of North Carolina Medical School inChapel Hill. _ Charles Craig
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