Gene Therapy for Kidney Failure
Reported October 19, 2005
By Julie Marks, Ivanhoe Health Correspondent
SAN FRANCISCO (Ivanhoe Newswire) — A new technique delivers gene therapy directly to blood vessels in patients with kidney failure who undergo dialysis. Researchers reported on the targeted approach at the Clinical Congress of the American College of Surgeons in San Francisco.
Currently, the most common method of providing access to the circulatory system for dialysis involves inserting an artificial blood vessel (graft) under the skin in the forearm or upper arm and surgically sewing it to the natural blood vessels. Over time, the inserted blood vessels block the area where the grafts are sewn to the vein. Patients then must have another procedure to clean out the existing artificial vein or to place a tube in the body to restore vascular access. “There is currently no medication, secret sauce, or magic wand to keep the veins of dialysis patients from scarring and growing closed,” says Jeffrey Lawson, M.D., Ph.D., from Duke University in Durham, N.C.
The study evaluated the effect of Trinam — a molecular medicine consisting of vascular endothelial growth factor gene (VEGF) in an adenovirus — on dialysis patients’ access grafts. VEGF controls and regulates the growth of blood vessels and also releases molecules from the surface of cells lining blood vessels to reduce the likelihood of blood clots. In animal studies, the therapy reduced the rate of vein scarring, suggesting that it may prolong the life of dialysis access grafts.
Investigators from Duke University studied 16 patients undergoing dialysis for kidney failure. Six patients received a low dose of 4 x 10e9 VEGF adenovirus particles. The particles were administered in solution to the outside of the patients’ vein using a novel biodegradable drug delivery reservoir device made of collagen.
After one year, patients have not experienced any signs of inflammation or infection in the vascular access graft or other serious adverse effects. Results also show the adenovirus has not spread outside the specific vein the surgeons treated. Although the study was not designed to evaluate the effectiveness of gene therapy, researchers say all but one of the vascular access grafts has remained open to date.
The study has expanded to include two additional centers and will test a higher dose of VEGF adenovirus particles. Dr. Lawson says: “This kind of technology is very exciting and some day will be in general use. That day will come when we understand more about what genes are expressed and how we can use specific ways to treat the biology of blood vessels. We are somewhere on that path, and this study is one of the important steps along the way.”
