By Randall Osborne

West Coast Editor

In the midst of fighting its legal war with Amgen Inc. over erythropoietin (EPO) - and while battling another, unrelated lawsuit from another biotech giant, Genzyme Corp. - Transkaryotic Therapies Inc. (TKT) said partner Aventis Pharma AG has filed in the U.S. and Europe for approval to market the pair's EPO formulation Dynepo.

"It should be a standard review period of about a year in Europe and 10 to 12 months in the U.S.," said Justine Koenigsberg, spokeswoman for TKT.

Aventis, the Frankfurt, Germany-based pharmaceutical arm of Aventis SA, wants the go-ahead to sell the red blood cell booster Dynepo for subcutaneous and intravenous administration to treat anemia in patients with chronic renal failure (including both dialysis and non-dialysis patients).

Analysts' reactions to the news were largely favorable, and outlooks on TKT were either bright or unchanged. "Investors should gain considerable confidence" in the company as a result of the second filing in several months, wrote analyst Tom Dietz, of Pacific Growth Equities Inc. in San Francisco.

"This certainly shouldn't be a negative for any investor, lawsuit or not," Dietz told BioWorld Today. "EPO is a small part of this company," he added.

Koenigsberg said TKT would not comment on legal matters, which are "separate" from other developments.

"We just keep going forward with what's in our pipeline," she said. "We have six additional gene-activated proteins, and the second one is also being developed with Aventis." The identity of the protein, in Phase I trials, has not been disclosed.

A third gene-activated protein is in development independently by TKT.

The Cambridge, Mass.-based company said it will present clinical data on Dynepo this fall at a scientific meeting in Canada, from Phase II and Phase III studies involving more than 1,300 patients with anemia related to chronic renal failure. A Phase III trial testing the drug in chemotherapy-related anemia also is under way, Koenigsberg said.

"We expect to complete that by year-end," she said.

Meanwhile, the company netted a milestone payment of $3.5 million from Aventis for seeking permission to market the drug.

"There will be additional milestones associated with approval," Koenigsberg said.

That cash, along with the $100 million raised in May, should help TKT pay attorneys' fees related to EPO and another drug, Replagal (alpha-galactosidase), for which TKT seeks marketing approval. In the ongoing EPO legal skirmish, dating from April 1997, Amgen, of Thousand Oaks, Calif., claims that TKT and partner Hoechst Marion Roussel AG (now Aventis) infringed upon its patents. EPO, marketed by Amgen under the name Epogen, is a glycoprotein hormone that regulates the level of red blood cells in circulation by stimulating their production in the bone marrow. (See BioWorld Today, May 22, 2000, p. 1.)

The Replagal lawsuit was filed last month by Genzyme, of Cambridge, Mass., which claims TKT's treatment for Fabry disease infringes on a patent licensed to Genzyme. Genzyme submitted its biologics license application for Fabrazyme, its Fabry disease drug, in June, about a week after TKT's application. The firms are racing for first approval and orphan drug status, which ensures seven years of market exclusivity. (See BioWorld Today, June 19, 2000, p. 1; June 26, 2000, p. 1; and July 26, 2000, p. 1.)

Dietz said, "I can't think of a lot of other biotech companies whose first products have made it all the way through [to marketing submissions]. There certainly is pressure on the stock that's indicative of the risk being assigned to the lawsuits. But the funny thing about all this is, there are going to be a lot of other lawsuits when companies get products on the market. This is just a window to the world of biotechnology in the future."

Replagal is part of TKT's Niche Protein platform, which also includes a drug for Hunter syndrome, a rare lysosomal storage disorder. Koenigsberg said the company will file an investigational new drug application on behalf of that drug this year.

TKT's stock (NASDAQ:TKTX) closed Thursday at $30.25, up $1.125.

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