New treatment trials for autosomal dominant polycystic kidney disease

The National Institutes of Health (NIH) and the PKD Foundation have launched two treatment trials for autosomal dominant polycystic kidney disease (ADPKD).

The common inherited disorder is characterized by cysts in the kidneys and other organs, high blood pressure, and aneurysms (bulges in blood vessels, which may burst) in the brain. Symptoms usually appear between the ages of 30 and 40 and include back and side pain and headaches. About half of ADPKD patients eventually develop kidney failure and require dialysis or a kidney transplant. The first Halt Progression of Polycystic Kidney Disease (HALT-PKD) patient enrolled last week at Emory University in Atlanta, one of seven recruitment sites .

"Decades of clinical and basic studies by NIH and others have delivered this exciting opportunity for translational research," says Catherine M. Meyers, M.D., a kidney specialist who directs HALT-PKD at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). "Naturally, we appreciate the PKD Foundation's invaluable guidance and support."

PKD Foundation President and CEO Dan Larson applauded the start of the trials. "PKD families are eager to learn of any potential benefits," says Larson. "Their hope and the hope of the PKD Foundation is that this will be a step toward finding a cure for PKD and improving the care and treatment of those it affects."

Carefully controlling blood pressure and using ACE-inhibitors or ARBs significantly delays or prevents kidney disease and failure from diabetes and other causes by reducing protein in the urine and preventing damage to the small blood vessels in the kidneys. Earlier trials of these treatments in PKD were not definitive, possibly because a small number of patients were involved.

Over the next 2 years, HALT-PKD will recruit more than 1,000 people with ADPKD and treat them for up to 4 years at centers in Atlanta, Boston, Cleveland, Denver, Kansas City, Kansas, and Rochester, Minnesota. The two trials will compare standard therapy using an angiotensin-converting enzyme inhibitor (ACE-inhibitor) to intensive therapy using both an ACE-inhibitor and an angiotensin receptor blocker (ARB). Patients will receive a device for measuring blood pressure at home, clinic visits, lab tests, and study medications at no charge. They will also have their kidney function estimated using a standard blood test measurement called eGFR and other measures to track progression of kidney disease.

HALT-PKD Study A, for people 15 to 49 years of age with early disease (eGFR >60), will also compare standard (120-130/70-80 mm Hg) and low (95-110/60-75 mm Hg) blood pressure targets and measure changes in cyst and kidney size using a Magnetic Resonance Imaging method developed by NIDDK's Consortium for Radiologic Imaging Studies of PKD. Study B, for people 18 to 64 and more advanced disease (eGFR 30-60), will track the time it takes eGFR to drop by 50 percent, the need for kidney failure treatment, and patient deaths.

PKD affects an estimated 500,000 people, about 90 percent of whom have ADPKD. In 2003, 23,000 people with cystic kidney disease (mostly PKD) received dialysis or a kidney transplant, making it this country's fourth leading cause of kidney failure. While genetic testing for ADPKD can help determine whether a family member can safely donate a kidney, testing can't predict onset of symptoms or severity of the disease, which also increases the risk of heart attacks, strokes and early death compared to the general population.

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