In what its chairman and CEO called a “transforming event” for the company, Atrix Laboratories Inc. received FDA approval for Eligard 7.5 mg, its one-month treatment for advanced prostate cancer.

The company said the approval specifically is for hormone-sensitive prostate cancer. Atrix, of Fort Collins, Colo., submitted the application in March. (See BioWorld Today, March 28, 2001.)

“Today is the transformation of Atrix from a drug development and drug delivery research, clinical studies company that has a lot of licensing and research deals to a company that has become a sales and earnings company,” David Bethune, chairman and CEO, told BioWorld Today.

Atrix’s stock (NASDAQ:ATRX) rose $1.22 Thursday to close at $22.51.

Formerly called Leuprogel One-Month Depot, Eligard is leuprolide acetate that is injected subcutaneously using Atrix’s Atrigel drug delivery system. Leuprolide is a leutinizing hormone-releasing hormone agonist. This forms a biomass that is absorbed slowly into the body and lowers the level of testosterone and is, in a sense, “chemical castration,” thus slowing the growth of the tumor or putting cancer in remission, Bethune said.

“It’s a lifesaving type of drug,” he said.

The product label has tentatively been agreed to with the FDA, and as it stands, Atrix is pleased with it, Bethune said in a conference call announcing the approval.

The U.S. market alone for such therapy is $1.2 billion, while the worldwide market is estimated at $2.4 billion, Atrix said. There are competing products for prostate cancer from Abbott Laboratories Inc., of Abbott Park, Ill., with Lupron Depot, and London-based AstraZeneca plc’s Zoladex. Also approved for breast cancer, Zoladex annual sales exceed $700 million, according to AstraZeneca.

“The competitors have very painful injections,” Bethune said, noting that both cause bleeding and pain. “We are hoping Eligard will be well received as the gentler product. We think that’s an important thing. Why have the additional misery when you have a condition like prostate cancer?”

It is effective, he said, because it lowers testosterone in the body to below 50 nanograms per decimeter.

Atrix also has longer-lasting formulations of Eligard. In September, Atrix submitted a new drug application for Eligard 22.5 mg (formerly Leuprogel Three-Month Depot) and plans to submit a third NDA during the latter part of the second quarter for Eligard 30 mg (formerly Leuprogel Four-Month Depot).

Sanofi-Synthelabo Inc., the New York-based U.S. arm of Paris-based Sanofi-Synthelabo, has the marketing rights to Eligard in the United States, an agreement struck in January 2001. (See BioWorld Today, Jan. 10, 2001.)

Sanofi will pay royalties and milestones to Atrix, which will manufacture the drug in Fort Collins.

“Sanofi will pay us a very handsome royalty and a nice manufacturing margin, which we will base on our ability to provide lower-cost manufacturing,” Bethune said. “We will share those benefits with Sanofi, but we will have an incentive to make the drug at less and less cost.”

In addition, Bethune said that Sanofi will pay Atrix a milestone payment of $6 million on the day of the first sale of Eligard. The launch date has not been determined, he said.

A Banc of America Securities analyst estimated the royalty rate to be 20 percent. The analyst at Banc of America Securities said his company expects Atrix to capture 15 percent of U.S. market share for prostate cancer therapies within three to five years.

Bethune declined to discuss how large a sales force Sanofi will dedicate to Eligard, citing competitive reasons. In terms of marketing strategy, Sanofi still is considering whether to launch the product as a stand-alone 30-day product, or wait until other expected FDA approvals are received.

“All of our economic models show having all products simultaneously would be best,” Bethune said.

Bethune also said, “We’re going to be ready to launch this at the time that it makes good sense and it’s the right marketing strategy.”

Atrix is partnered with MediGene AG, of Martinsried, Germany, for marketing of the product in Europe, where a marketing authorization application was filed in Germany last month. Faulding Pharmaceutical Inc., a division of Melbourne, Australia-based F.H. Faulding & Co. Ltd., has rights in Australia. (See BioWorld Today, April 6, 2001, and Sept. 27, 2001.)

“We are currently having very serious conversations with [potential] Japanese partners,” Bethune said.