By Randall Osborne

West Coast Editor

Immunex Corp. reaped $795 million by selling 20 million shares of stock at $39.75, and American Home Products Corp. (AHP) sold 50 million more at the same price, bringing the total proceeds of the offering to $2.78 billion.

AHP, of Madison, N.J., is granting underwriters an overallotment option of up to 10.5 million more shares that, if fully exercised, would drop its ownership of Seattle-based Immunex from about 55 percent to 41 percent.

If the option is not exercised, the number would be 43 percent.

Immunex said in August it would change its relationship with AHP, reducing the latter's stake while buying from AHP a manufacturing facility for Enbrel (etanercept), Immunex's drug for rheumatoid arthritis, in Rhode Island, and gaining a credit line of up to $550 million through third parties for a new research and technology center. (See BioWorld Today, Aug. 11, 2000.)

Originally, the offering was to be 60 million shares.

"We were able to exceed that, because of demand," said Kris Greco, spokesperson for Immunex.

AHP loses a seat on Immunex's board, whether or not the overallotment option is exercised, Greco said.

"Below 45 percent [ownership] is the threshold," she said.

Earlier this month, AHP converted a $450 million subordinated note into 15.5 million new Immunex shares, taking away annual interest payments by Immunex to AHP of about $13.5 million.

Lead managers for the offering are Morgan Stanley Dean Witter and Merrill Lynch & Co., both of New York, and co-managers are Credit Suisse First Boston, Lehman Brothers, and Bear, Stearns & Co., all of New York, and Banc of America Securities LLC and Robertson Stephens, both of San Francisco.

With 502.9 million shares outstanding, Immunex's stock (NASDAQ:IMNX) closed Friday at $41.562, up $1.812.