By Randall Osborne

A month after ending its platelet donation clinical trials of megakaryocyte growth and development factor (MGDF) because a patient developed low platelet counts and neutralizing antibodies, Amgen Inc. has quashed studies in cancer patients as well.

"The program is stopped," said David Kaye, spokesman for Thousand Oaks, Calif.-based Amgen. "We found additional patients [with neutralizing antibodies in the platelet-donation trials] and evidence there's some antibody activity on the cancer side."

Analysts hardly blinked at the news.

"I don't think it's a big deal or a surprise to anybody who had their eyes and ears open," said Matthew Geller, an analyst with CIBC Oppenheimer & Co., in New York. "It failed in leukemia and it had safety problems. It just wasn't a drug."

Mary Ann Gray, senior vice president of Raymond James & Associates, in New York, said research on the platelet booster has not lived up to its apparent promise, for Amgen or others investigating it.

"There was such a to-do about it when it came out, but the results have not been stellar," Gray said. "People have moved on to other things."

Amgen quit MGDF trials in platelet donation in August, but continued those evaluating patients in chemotherapy, including some in a Phase III trial for bone-marrow transplantation. In a Phase II trial, the drug boosted platelet levels by 70 percent in chemotherapy patients. (See BioWorld Today, Aug. 19, 1998, p. 1.)

Two years ago, Amgen disclosed negative results from a Phase I study testing MGDF's ability to restore platelets in acute myeloid leukemia patients undergoing chemotherapy. (See BioWorld Today, Oct. 17, 1996, p. 1.)

Amgen To Continue Drilling For Next Gusher

Kaye said Amgen has "about a dozen other products" in its pipeline. "It's kind of like oil wells," he said. "Some hit, some don't."

The company's two blockbuster drugs are Epogen (Epoetin alfa), a red blood cell booster, and Neupogen (Filgrastim), a white blood cell booster. Earlier this year, the company began a Phase III trial with its second-generation Epogen product: novel erythropoiesis stimulating protein (NESP) for dialysis patients.

"Everything is moving forward," Kaye said. "We have a bunch [of compounds] in Phase I or Phase II."

Amgen's stock (NASDAQ:AMGN) closed Friday at $72.50, down $1.50. *