BioWorld International Correspondent

ZICHRON YA'AKOV, Israel - The District Court of Tel Aviv-Jaffa will be the venue for a patent suit that Genzyme Corp. brought against Transkaryotic Therapies Inc., both of Cambridge, Mass.

TKT announced that Genzyme filed the suit, which claims that TKT's open-label Phase I/II trial to evaluate the safety and clinical activity of investigational gene-activated glucocerebrosidase (GA-GCB) infringes one or more claims of Israeli Patent No. 100,715. That patent covers Genzyme's novel cell-culture processes that have been critical in the mass manufacture of Genzyme's glucocerebrosidase, Cerezyme, also called imiglucerase for injection, for Gaucher's patients.

Glucocerebrosidase, a lysosomal glycoprotein enzyme that catalyzes the hydrolysis of the glycolipid glucocerebroside, is deficient in Gaucher's disease.

An additional motion for a preliminary injunction, including a request for seizure and destruction of all GA-GCB being used to treat patients in TKT's ongoing trial, already was rejected by the judge.

GA-GCB is being examined in 12 patients from several countries with Type I Gaucher's disease. TKT expects to report top-line data from the study in the second half of 2005.

"We believe Genzyme's efforts to try and disrupt our ongoing clinical development of GA-GCB are an improper attempt to extend its monopoly in the area of Gaucher's disease," said Kerry Flynn, vice president of intellectual property and licensing at TKT. "We do not believe we infringe any valid claim or that there is a reasonable likelihood that this unprecedented tactic will interrupt our clinical trial. We intend to honor our commitment to continue treating our Gaucher's patients with GA-GCB."

A comparison of Genzyme's Cerezyme with TKT's GA-GCB shows that GA-GCB has the native sequence and human glycosylation. Cerezyme - made from a mutant gene that translates into an analogue of the human enzyme ß-glucocerebrosidase, which differs from placental glucocerebrosidase by one amino acid - has hamster glycosylation.

Cerezyme is produced by recombinant DNA technology using Chinese hamster ovary cell culture. GA-CBC is produced by TKT's gene-activation technology, what TKT calls the third wave in the evolution of protein-production technology.

When asked to comment on the differences between the drugs, Bo Piela, director of Genzyme's corporate communications, referred to the complaint.

Michael Astrue, president and CEO of TKT, told BioWorld International: "I have never seen a company try to close down an ongoing clinical trial. If Genzyme had succeeded with its emergency ex parte motion to immediately seize and destroy all GA-GCB in Israel, it would have devastated the patients in the trial, some of whom have relocated from other countries in order to obtain GA-GCB. Fortunately, the judge rejected this unprecedented tactic even though we were not yet a party to the lawsuit and were not present in the courtroom."

Earlier this month TKT announced sales of its gene-activated Replagal, an enzyme-replacement therapy for Fabry's disease, would slightly exceed its 2004 guidance of $67 million to $77 million. The drug is approved in 34 countries outside the U.S.

In April, TKT raised $94 million through a convertible debt offering.

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