By Mary Welch

Genzyme General gained ground in the battle with Transkaryotic Therapies Inc. (TKT) to develop a therapy for Fabry disease, with the disclosure that Fabrazyme, an enzyme replacement therapy, achieved the primary endpoint in a Phase III trial. The filing of the biologics license application (BLA) remains on track for late June.

"It is obviously a positive for Genzyme," said Bill Tanner, vice president with New York-based SG Cowen Securities Corp. "We had been hearing things [suggesting] that Fabrazyme might be in trouble. Now we have a few more of the pieces to the puzzle, and it looks like a filing will take place in the second quarter - and we're already one-third of the way through the second quarter. No one really knows where TKT is in the process, but it looks like the gap is closed [in the race for the BLA filing]. Who knows who is where, but this sheds a little light."

So far, Genzyme has not disclosed many details about the Phase III study, other than that Fabrazyme was tested in a double-blinded, randomized and placebo-controlled trial that was conducted at eight medical centers in the U.S. and Europe. The extended trial protocol now in place has allowed all patients who participated in the pivotal trial, including placebo patients, to receive enzyme replacement therapy. Data will continue to be collected on those patients.

In the pivotal trial, Fabrazyme (afgalsidase beta for injection) infusions were well-tolerated, the company said. No patients discontinued treatment because of adverse reactions.

"Obviously, we are pleased," said Genzyme spokesman Bo Piela. "We are on schedule to file the BLA in the U.S. and [to file] in Europe shortly after that. We will present the data from the trial at a conference this fall."

In anticipation of the launch, Cambridge, Mass.-based Genzyme has begun physician and patient outreach and education, sales-force preparation and manufacturing scale-up.

TKT, also based in Cambridge, completed a Phase II trial of its Fabry disease treatment, Replagel (alpha-galactosidase A) late last year. In January 1999, TKT struck a collaboration with Sumitomo Pharmaceuticals Co. Ltd., of Point Richmond, Calif., to commercialize Replagel in Japan and Asian countries.

In an interview with BioWorld Today last fall, TKT's vice president and chief financial officer, Daniel Geffken, said that it was possible the Phase II trial data will support a regulatory filing, but declined to say when an actual filing might take place. (See BioWorld Today, Nov. 1, 1999, p. 1.)

Fabry disease is an inherited metabolic disorder caused by a deficiency of the enzyme alpha-galactosidase, which causes the body not to break down certain naturally occurring glycolipids. As a result, these glycolipids then accumulate in the lining of blood vessels within the kidney, heart and other organs.

Patients suffer severe pain, numbness, kidney failure and cardiac disease. Fabry disease is estimated to affect one in 40,000 men worldwide. Death typically occurs around age 40. There is no known cure.

Genzyme General's stock (NASDAQ:GENZ) closed at $48, down 81 cents.