By Mary Welch

Renagel (sevelamer hydrochloride), a non-absorbed polymer-based phosphate binder for patients with end-stage renal disease (ESRD), was approved by the FDA, triggering a $15 million payment by Genzyme Corp. to GelTex Pharmaceuticals Inc., with another $10 million to follow in a year.

The joint venture between Cambridge, Mass.-based Genzyme and GelTex, of Waltham, Mass., has been "a real working partnership, where the expertise from both sides was leveraged," said Christi Van Heek, senior vice president at Genzyme.

Genzyme has hired a 42-person sales staff (complete with its own vice president of sales) to market Renagel in 38 territories. The product, which should be available in pharmacies by the end of the month, will cost $0.46 per capsule, or between $1,100 and $1,500 per year, Van Heek said. "You take it with every meal, so the ultimate yearly cost varies with the severity, the prescribed dose and compliance."

Renagel, with a market potential estimated at $200 million per year, works by binding to dietary phosphate in the intestine before it can reach the bloodstream, thus reducing through excretion the elevated phosphorus levels that occur in about 95 percent of dialysis patients.

About 220,000 patients in the U.S. suffer from ESRD, with the number growing by 6 percent to 8 percent per year. The number in Europe is pegged at about 170,000. "The increase is [getting] larger due to an aging population and a high incidence of hypertension and diabetes, both leading causes of end-stage renal disease," said Van Heek.

ESRD patients retain excess phosphorus, normally excreted through the kidneys in urine. If left untreated, elevated blood phosphorus levels can lead to a number of serious conditions, including renal bone disease and soft-tissue and vascular calcifications.

In trials with Renagel, side effects such as nausea, constipation, diarrhea, flatulence and dyspepsia were similar to those of patients who took a placebo, Van Heek said.

The joint venture established last year between Genzyme and GelTex calls for a 50-50 split of sales revenues as well as expenses. Genzyme took a $2.5 million equity position in GelTex. Japan and certain Pacific Rim countries are excluded from the deal, since they are covered under an earlier agreement by GelTex with Chugai Pharmaceutical Co. Ltd., of Tokyo. Renagel is currently under regulatory review for marketing approval in Europe and Canada. (See BioWorld Today, June 19, 1997, p. 1.)

Renagel is the first product to be approved from GelTex's non-absorbed polymer technology, Van Heek said. "For us, it's an important product in a new therapeutic area," she added. "And, most importantly, it is an important advance in the management of patients with [ESRD]."

Current treatments involve phosphorus binders that contain calcium or aluminum. "Renagel is unique in that it is non-absorbed and contains no calcium or aluminum," she said. Too much calcium can lead to hypercalcemia, causing fatigue, muscle weakness, anorexia, nausea and constipation. Aluminum is toxic and can lead to dementia and bone disease.

"Renagel is a simpler treatment," Van Heek said.

Genzyme's Thyrogen, an adjuvant for the management of thyroid cancer, is under FDA review. The company expects word from the agency by year's end.

GelTex's second product, CholestaGel, a non-absorbed hydrogel that binds and removes bile acids from the intestinal tract, thus stimulating the liver to remove cholesterol from the bloodstream, is in Phase III trials. The company expects data from those trials to be available by the first quarter of 1999, with a new drug application expected to be filed by the middle of next year.

GelTex's stock (NASDAQ:GELX) closed Monday at $23.875, down $1.125.

Genzyme's stock (NASDAQ:GENZ) closed Monday at $41.937, down $0.125. *

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