Genzyme Corp. Pins Hopes on Unexpected Promise in Drug for Dialysis Patients.

Byline: Naomi Aoki

Apr. 10--No one expected the drug Renagel to be a blockbuster. It was designed to help a subset of dialysis patients who had built up excessively high levels of calcium, and it was expected to reap revenues of roughly $200 million a year at its peak.

In 1999, several months after the drug had reached the market, however, a dramatically different picture began to emerge.

Renagel clears phosphorous from the bodies of patients whose kidneys can no longer perform that function. But unlike its rivals, it does so without using calcium, and studies were beginning to suggest that an overload of calcium was behind the unusually high rate of heart disease in dialysis patients. If the theory proved true, Renagel could improve patients' health, save lives, and become a billion-dollar-a-year drug.

"We began to think that we may be able to change the world for these patients,"' said Mike Raab, senior vice president of therapeutics and general manager of the Renagel business at Genzyme Corp.

Today, Genzyme is pinning its hopes for growth on Renagel. Sales of the dialysis drug skyrocketed in its first three years on the market, reaching $177 million last year. By 2010, the company expects sales to hit $1 billion a year. Its success is critical to the Cambridge company at a time when sales of its top-selling drug are slowing. Cerezyme, a drug to treat the rare inherited Gaucher disease, has long provided the lion's share of company's revenue.

Many analysts believe Renagel will succeed in taking over for Cerezyme, providing the growth investors expect of Genzyme until other drugs in its pipeline reach the market. But others have doubts. Although evidence is mounting that calcium from other drugs used to clear phosphorous from dialysis patients is collecting in their tissues and hardening their arteries, the theory that these drugs increase the risk of heart-related complications and deaths has not yet been proven.