SOUTHERN CALIFORNIA ENTERPRISE : Amgen’s Latest Home Run in a Winning Streak? : Biotech: Thousand Oaks firm, rivals make breakthrough toward blood-clotting drug. But the product appears to be 5 years or more away from the market.

For decades, scientists searched for a hormone believed to have the awesome power to make blood clot.

Now, three biotechnology companies, including Thousand Oaks-based Amgen Inc., say they’ve found that hormone--dubbed thrombopoietin--and cloned it.

Their announcements, all made within a month, represent a breakthrough and offer hope to thousands of cancer patients, for whom blood clotting is often impaired during treatment.

The medical community is elated.

“We all want to get our hands on it,” said Dr. Stephanie Williams, who treats cancer patients in Chicago.

Financial analysts, though, are more restrained. As promising as the discovery appears, a drug product is five years or more from the market, and Wall Street is more interested in what new products these companies have to offer now.

For Amgen, that’s not much. The 14-year-old company, which spent $225 million on research and development last year, is still going strong with two highly successful drugs developed in the late 1980s. Thanks to its two blood cell-producing aids, Epogen and Neupogen, Amgen is one of the world’s most successful biotechnology companies. It made $383.3 million last year on revenue of $1.37 billion.

If thrombopoietin is approved, most analysts estimate its annual sales at between $250 million and $500 million, compared to $719.4 million for Neupogen in 1993.

But thrombopoietin has yet to undergo the time-consuming and rigorous processes of animal testing, human trials and the layers of Food and Drug Administration reviews required before it can go on the market.

Analysts say they are looking for a more immediate encore to Epogen and Neupogen that would propel Amgen’s growth through the end of the decade. Though Amgen is expected to remain profitable, its growth is expected to slow in the late 1990s as sales of its products level off.

Thrombopoietin “has captured people’s imagination . . . but in terms of the commercial aspects, this is still a long way off,” said Edmund A. Debler, an analyst at the health care investment firm Mehta & Isaly in New York. He added that “Amgen’s (research) pipeline is still weak.”

Neupogen and Epogen “made Amgen the company of the ‘80s, but what will make them the company of 2000?” Debler asked.

Such naysaying is the curse of success, responded Amgen’s senior vice president for research, Daniel Vapnek.

The problem, Vapnek said, is undue expectations built on the company’s explosive entrance. Biotechnology “is a home-run business,” he said, and Amgen hit two home runs early on, with Neupogen and Epogen. “It’s difficult to come up with products like that on a regular basis.”

Whether thrombopoietin will represent another home run depends on how well Amgen fares against competitors in the race to claim a patent.

South San Francisco-based Genentech and Seattle-based Zymogenetics Inc., a subsidiary of Novo Nordisk of Denmark, published their findings on thrombopoietin in the June 16 issue of the British journal Nature. Amgen--which is working on thrombopoietin with the pharmaceutical arm of Japan’s Kirin Brewery--published its report on July 1 in the American journal Cell. The three firms appear to have isolated the same molecule and are poised to begin clinical trials.

Because the three companies published their results just weeks apart, a protracted patent process that could end in court seems inevitable, said Debler. In this country, “it will probably come down to opening up the lab books to see who found it first,” he said.

Alternatively, the companies could avoid a court battle by settling the matter among themselves and marketing any resulting drug product together, added Debler, but that would mean sharing the potential profits.

The route to market may be quicker if thrombopoietin proves as effective as early signs indicate. The three companies appear to have cloned the same specific, highly potent molecule, one the body manufactures to stimulate production of the blood cells called platelets.

Platelets are the wafer-shaped cells that cause blood to clot. Without clotting, a person can bleed to death from a cut or internal hemorrhaging.

Platelets pose big problems for cancer patients undergoing certain types of chemotherapy, which involves bombarding the body with poisonous drugs to kill cancer cells. “They try to give the dose that kills the tumor without killing the person,” explained Don Foster, a molecular biologist at Zymogenetics and senior author of the Nature paper.

Chemotherapy can deplete certain blood cells. Patients who lose too many white blood cells are prone to infections; those who lose too many platelets have problems with bleeding.

Drugs are available to stimulate the replacement of white blood cells. One is Amgen’s Neupogen. But so far, there is no drug to aid the rebuilding of platelets.

That means doctors must limit chemotherapy dosage to give the blood a chance to restore damaged platelets, or resort to risky and expensive platelet transfusions.

Doctors believe that doses of thrombopoietin could induce a frenzy of platelet-making in the blood, allowing for continuous chemotherapy.

A viable drug could also shorten recovery time for cancer patients who have undergone bone marrow transplants. It may also prove useful in treatment of blood disorders.