By Matthew Willett

Genzyme Corp., in a race with Transkaryotic Therapies Inc. to market a Fabry disease treatment, said Tuesday it filed a lawsuit against TKT in U.S. District Court in Wilmington, Del., alleging patent infringement.

The suit alleges TKT's manufacture and use of Replagal (alpha-galactosidase) infringes on a patent licensed to Genzyme.

"We know that TKT uses mammalian cells to make their alpha-galactosidase product," said Tom DesRosier, Genzyme's senior vice president and chief patent counsel. "The patent covers the manufacture of this particular enzyme, alpha-galactosidase, and so, although the processes we use to manufacture the same enzyme are slight different, the patent coverage is broad enough to cover both the processes."

DesRosier said he believes the suit could take two to three years to resolve.

Transkaryotic representatives were unavailable for comment late Tuesday afternoon, but TKT CEO Richard Selden said in a prepared statement, "We strongly believe that TKT's activities relating to Replagal do not infringe the '804 patent, and, in addition, that the patent is not valid. We intend to vigorously defend this lawsuit and expect to prevail. It's a shame that Genzyme has chosen to compete based on a frivolous lawsuit rather than on the merits of their product.

"Furthermore," Selden said, "with over 5,000 rare diseases affecting 20 million Americans, Genzyme is clearly wasting resources that could be better allocated toward helping patients."

The companies both submitted biologics license applications for their respective Fabry disease products in June. Genzyme's submission for Fabrazyme came about a week after TKT's for Replagel. The first product to gain approval gets orphan drug status, which gives seven years of market exclusivity. (See BioWorld Today, June 19, 2000, p. 1; and June 26, 2000, p. 1.)

Genzyme spokeswoman Caren Arnstein said the suit was timed with TKT's marketing efforts in mind.

"The issue is that the patent is for production and use," Arnstein said. "Those [patents] aren't accepted while a product is in clinical development. The fact that they've recently filed a BLA for marketing approval signals their intent to manufacture and market a product, and that infringes on our patent."

Fabry disease is a rare inherited genetic disorder caused by a deficiency of the lysosomal enzyme alpha-galactosidase A. Consequent accumulations of ceramidetrihexoside cause the sufferer extreme pain, serious renal and cardiovascular disease, and stroke. The disease is estimated to affect one in 40,000 men worldwide, and between 1,000 and 2,000 patients in the U.S. suffer from the disease.

The suit alleges infringement of U.S. patent No. 5,256,804, licensed to Genzyme by the Mount Sinai School of Medicine. Genzyme also holds U.S. patent 6,066,626, which covers aspects of gene therapy for Fabry disease.

Both companies have pursued enzyme replacement therapies as treatment for the disease.

Genzyme disclosed news of the suit after the market closed Tuesday.

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