Vidyya Medical News Service
Volume 6 Issue 305 Published - 14:00 UTC 08:00 EST 31-Oct-2004 Next Update - 14:00 UTC 08:00 EST 1-Nov-2004
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Fosrenol (R)maintains bone health status of end-stage renal disease patients

Long-term treatment with Fosrenol (R) (lanthanum carbonate), a new non-calcium, non-aluminum phosphate binder, does not promote bone softening or cause harmful effects on bone, according to data presented this week at the American Society of Nephrology (ASN) annual meeting in St. Louis, Mo.

Even with a low-phosphorus diet, most ESRD patients develop hyperphosphatemia (high phosphate levels in the blood). Without effective treatment, hyperphosphatemia may lead to renal osteodystrophy, a collection of bone diseases characterized by bone pain, brittle bones, skeletal deformities and fractures.

"Since ESRD patients often have fragile bones, it is critical that phosphate binders not worsen bone status," said Dr. Eliseo Salinas, Shire's Chief Scientific Officer and Executive Vice President of Global Research & Development. "Patients who take Fosrenol (R) over the long-term generally are able to maintain their bone health status."

The U.S. Food and Drug Administration recently approved Fosrenol (R) on Oct. 26. According to experts, Fosrenol (R) may help simplify the management of hyperphosphatemia because it is an effective, easy-to-take, chewable tablet that does not have to be taken with fluids.

Data from over 400 bone biopsies representing the largest bone biopsy data set in ESRD patients were presented at ASN.

In an important study, which evaluated bone biopsies in 197 subjects (100 patients receiving Fosrenol (R) and 97 patients receiving comparator) prior to and after one year of treatment revealed no evidence of softening of the bone (osteomalacia) in patients receiving Fosrenol (R).

In another poster presentation, investigators used five measures of bone structure and content to examine bone samples from 11 patients who completed more than four years of treatment with Fosrenol (R). Treatment with Fosrenol (R) for more than four years is not associated with the toxic effects on bone associated with aluminum-based phosphate binders, particularly softening of bone (osteomalacia) that results from abnormal mineral metabolism.

"Since only about one-third of ESRD patients have phosphorus levels within acceptable ranges, we need new safe and reliable methods to control phosphorus levels," said Hartmut H. Malluche, M.D., Robert G. Luke Chair in Nephrology, Professor of Medicine and Chief, Division of Nephrology Bone and Mineral Metabolism at the University of Kentucky in Lexington, Kentucky. "Our documentation that Fosrenol (R) does not have the toxic, bone-softening effect associated with aluminum-based phosphate binders is welcome news for the ESRD community."

Managing Hyperphosphatemia
Phosphorus, an element found in nearly all foods, is absorbed from the gastrointestinal tract into the bloodstream. When the kidneys fail, they no longer effectively remove phosphorus, even with the help of blood-cleansing dialysis machines. While the normal adult range for phosphorus is 2.5 to 4.5 mg/dL, the blood phosphorus levels of many patients on dialysis exceed 6.5 mg/dL. Such levels have been linked to a significantly higher illness and death risk for patients who have undergone at least one year of dialysis.

Of the approximately 20 million Americans who have some form of kidney disease, as of 2002, more than 512,000 have developed ESRD, a figure that has grown 400 percent over the last 20 years.

Diet restrictions alone generally cannot control phosphorus levels and patients traditionally manage hyperphosphatemia by taking phosphorus-binding agents at every meal and snack. Such binders help to "soak up" phosphorus in the gastrointestinal tract, before it can be absorbed into the blood. Despite the availability of these agents, it remains a challenge for some ESRD patients to maintain target ranges. According to the National Kidney Foundation's new Kidney Disease Outcomes Quality Initiative (K/DOQI) Clinical Practice Guidelines for Bone Metabolism and Disease, Guideline 3, Evaluation of Serum Phosphorus Levels, fewer than 30 percent of dialysis patients are able to maintain serum phosphorus levels in the target range.

The K/DOQI Clinical Practice Guidelines for Bone Metabolism and Disease also note in Guideline 5, Use of Phosphate Binders in Chronic Kidney Disease (CKD), that non-calcium and non-aluminum phosphate binders are a preferred first-line treatment option in lowering serum phosphorus levels. Because Fosrenol (R) does not contain calcium or aluminum, it meets the K/DOQI recommendations as one of the preferred first-line treatment options in lowering serum phosphorus levels.

Fosrenol (R)
Fosrenol (R) works by binding to dietary phosphorus. Once bound, the Fosrenol (R)/phosphorus complex cannot pass into the bloodstream and is eliminated from the body. Consequently, a patient's overall absorption of phosphorus from the diet significantly decreases.

Shire has conducted an extensive clinical research program for Fosrenol (R) involving approximately 2,000 patients, some of whom have been treated for up to 36 months. In clinical trials, Fosrenol (R) was generally well-tolerated.

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