Expanding its sole therapeutic program, Advanced Magnetics Inc. began a Phase III study of its investigational iron-replacement therapeutic, ferumoxytol.

The U.S.-based, multicenter trial is designed to evaluate the intravenous product in anemic chronic kidney disease patients who are on hemodialysis. Its primary endpoint is the change in hemoglobin from baseline - a standard anemia measure.

Two Phase III studies already are under way in anemic chronic kidney disease patients who are not yet on dialysis.

Though Lisa Gordon, the director of business development and investor relations at Advanced Magnetics, did not specify the latest study's duration or the number of patients planned for enrollment, she said the Cambridge, Mass.-based company expects to submit a new drug application to the FDA by the end of next year for anemic patients, whether or not on dialysis.

Ferumoxytol is made of bioavailable iron that allows for more efficient replenishment of a body's iron stores than oral iron supplements, without the common side effects. Most hemodialysis patients use erythropoietin, Gordon said, and chronic use of erythropoietin requires supplements of intravenous iron, since oral iron is inadequate for replacing such stores.

Advanced Magnetics added that the use of ferumoxytol provides greater flexibility in both its administration and the amount of iron that can be given in comparison to other currently marketed intravenous iron replacements - Ferrlecit (sodium ferric gluconate, from Watson Pharma Inc.) and Venofer (iron sucrose injection, from American Regent Inc.). Both of the products are administered over five-minute infusions, with Ferrlecit delivered in a 125-mg dose and Venofer at 100 mg, while a single 500-mg ferumoxytol dose is administered by way of a 17-second bolus.

"The standard dose of iron is one gram for anemic patients," Gordon told BioWorld Today. "It's believed that that is the clinically significant amount of iron to get the boost of hemoglobin they're looking for. And with these [already marketed] products, it takes eight to 10 dialysis sessions or visits to a physician to get that gram of iron in."

Advanced Magnetics also is pursuing labeling beyond the hemodialysis market, for the predialysis patient population, and Gordon said the Phase III study is designed to support both indications. Neither Ferrlecit nor Venofer are indicated for predialysis patients.

"We believe the rapid bolus and the large, 500-mg dose has greater advantages out of the hemodialysis market, where patients aren't seen as frequently," she added. "The Phase III study designs are based on our Phase II designs and results, and also are based on what Ferrlecit and Venofer were approved on in the last five years."

Recently reported Phase II data, which the company detailed at last month's National Kidney Foundation meeting in Chicago, showed that ferumoxytol effectively supplied bioavailable iron and increased body iron stores in anemic hemodialysis patients. Other findings, reported last fall at the American Society of Nephrology meeting in San Diego, also supported its use in treating iron deficiency in hemodialysis patients receiving erythropoietin and pointed to its large-dose, rapid delivery.

Further development of ferumoxytol could include its use in oncology for chemotherapy-induced anemic patients, who also have their iron depleted by use of erythropoietin. But Advanced Magnetics has yet to begin a program for ferumoxytol in oncology.

"We're trying to go where the market is already established," Gordon said, "and then we'll expand out."

The product also is in Phase II trials for use as a contrast agent in magnetic resonance angiography. Data recently reported at the American Society of Neuroradiology meeting in Seattle showed that the use of ferumoxytol provided positive delineation of the carotid arteries in patients and volunteers. Another imaging use for the product, to evaluate ferumoxytol in both angiographic imaging and delayed imaging in patients with primary or metastatic brain tumors, is the subject of a clinical study being carried out by the National Cancer Institute in Bethesda, Md.

On Wednesday, Advanced Magnetics' stock (AMEX:AVM) dropped 21 cents to close at $8.91.