By Randall Osborne

West Coast Editor

It ain't over until it's over, as racetrack gamblers like to say, and Genzyme General surged ahead by submitting a biologics license application (BLA) for its Fabry disease treatment - less than a week after Transkaryotic Therapies Inc. did the same.

As the two jockey for position with the FDA, neither has a time advantage, and the winner gets seven-year exclusivity as an orphan drug in the "multi-hundred million dollar" potential market, said Elise Wang, first vice president of PaineWebber Inc. in New York.

"We're of the opinion that only one of these products will make it out," Wang told BioWorld Today. Both companies, she added, believe the same.

Cambridge, Mass.-based Genzyme submitted a BLA for Fabrazyme (agalsidase beta), a recombinant enzyme replacement therapy made from Chinese hamster ovary cells for the inherited disorder, which is caused by a shortage of alpha-galactosidase. Fabry disease afflicts about 2,000 patients in the U.S., who typically die by age 40 because of organ failure.

Days earlier, TKT submitted its BLA for Replagal (agalsidase alfa), and based the filing on clinical data from two independent trials conducted in the UK involving about 50 patients. (See BioWorld Today, June 18, 2000, p. 1.)

Whereas TKT's data were taken from trials considered to be Phase II, Genzyme based its BLA on results from a Phase III trial, designed with help from the FDA.

"The agency has blessed, at least, what the endpoint is," Wang said.

Otherwise, the race is pretty much even - and neither company has provided enough details of its trials for a close comparison. Both are expected to tell more at scientific meetings this fall.

Genzyme, meanwhile, remains modest, not wanting to jinx its apparent lead with the FDA.

"It's very much a race," Genzyme spokesperson Bo Piela acknowledged. "We said we were going to file this submission by the end of the first half of the year, and we've done it right on schedule. There have been a lot of opinions as to how this will be resolved."

If approved, Fabrazyme could be launched late this year or early next, Wang said.

Complicating the issue somewhat is the deferment of action for several weeks by the FDA's Center for Biologics Evaluation and Research on BLAs, while the center updates its database. Although the delay will affect the time line for decisions, it's not expected to play a role in determining which company ultimately wins. (See BioWorld Today, June 23, 2000, p. 1.)

Genzyme's stock (NASDAQ:GENZ) closed Friday at $55.687, down $1.187. TKT's shares (NASDAQ:TKTX) ended the day at $34.312, up 62.5 cents.

"People are taking bets on the companies," Wang said, referring to the stock-price changes. TKT's rise has "more to do with Amgen than what's going on with Genzyme," she added.

TKT is fighting Thousand Oaks, Calif.-based Amgen Inc. over patents related to erythropoietin. The lawsuit was originally filed against TKT and partner Hoechst Marion Roussel AG (now Aventis), of Frankfurt, Germany, in April 1997. (See BioWorld Today, May 22, 2000, p. 1.)