By Randall Osborne

To keep its cupboard stocked with ready money, Amgen Inc. filed for a shelf registration to sell up to $500 million in debt securities.

The filing lets Amgen, of Thousand Oaks, Calif., raise funds through issuing debt securities "from time to time, in one or more series" by updating regularly filed reports with the Securities and Exchange Commission. A shelf registration saves time and paperwork, so the company can quickly take action when market conditions are favorable.

"Basically, it allows us to raise cash at some point for general corporate purposes," said David Kaye, spokesman for Amgen. "We've done these in the past."

The most recent shelf registration by Amgen was in late 1991. It was for $200 million, and was increased in January of this year by $13 million.

None of the $500 million in the most recent shelf registration has been earmarked for specific expenses, Kaye said.

Last month, the FDA cleared Amgen's Infergen (interferon alfacon-1) for marketing for hepatitis C. The drug faces its stiffest competition from Intron-A (interferon alfa-2b), marketed by Schering-Plough Corp., of Madison, N.J. (See BioWorld Today, Oct. 8, 1997, p. 1.)

"The sales force has just in the last couple of weeks gotten out there and begun to explain it to physicians," Kaye said. "It's still very early."

Another interferon product, Roferon-A (interferon alfa-2a) is copromoted by Gilead Sciences Inc., of Foster City, Calif., and Roche Holding Ltd., of Basel, Switzerland.

Interferon alfa-2a and alfa-2b once were the only approved therapies for hepatitis C, but patients treated with them often failed to respond or relapsed. Infergen, a consensus alpha interferon that is formulated differently from the natural protein, showed effectiveness for such patients in clinical trials.

Other drugs marketed by Amgen are Neupogen (Filgrastim), which restores white blood cells destroyed by cancer chemotherapy, and Epogen (Epoetin alfa), which stimulates the production of red blood cells and is used against anemia associated with chronic renal failure.

As of Sept. 30, Amgen had $1.1 billion in cash, with a net income of $465 million for the first nine months of 1997.

Amgen's stock (NASDAQ:AMGN) closed Wednesday at $51.875, down $0.375. *