Immunex Corp. announced late Monday that the Federal TradeCommission (FTC) has voted not to oppose the Seattlecompany's reacquisition of exclusive U.S. marketing rights togranulocyte macrophage-colony stimulating factor (GM-CSF)from its development and co-marketing partner Hoechst AG.

The FTC decision clears an obstacle in Immunex's merger withAmerican Cyanamid Co.

Immunex and Hoechst-Roussel Pharmaceuticals Inc. have beenco-marketing GM-CSF in the U.S. as Leukine and Prokine,respectively. In July 1992 Immunex agreed to pay undisclosed,but significantly higher, royalties on its U.S. sales of Leukineto Hoechst's German affiliate Behringwerke AG. In return,Hoechst-Roussel Pharmaceuticals Inc., Hoechst's U.S.subsidiary in Somerville, N.J. agreed to halt its U.S. sales ofProkine.

The terms of this agreement were subject to FTC review onantitrust grounds, so until now "both companies have continuedto sell both versions of the drug," said Jason Rubin, Immunex'svice president of corporate communications. Now that the FTChas decided not to block the transfer, "we will moveimmediately to sell a single drug," Rubin told BioWorld.

The resolution of the FTC's investigation bears on the recentlyamended terms of Immunex's merger with American Cyanamid,announced March 18. If Immunex had been unable to completeits reacquisition of the U.S. rights to GM-CSF, Cyanamid wouldhave ended up owning 54.8 percent of the company, rather thanthe 53.5 percent as outlined in the original merger agreementlast December.

"This is very good news in light of the amended proxy theyfiled," commented Jay Silverman, an analyst with WertheimerSchroder. "If the FTC had opposed the transaction, Immunexwould have had to issue more stock to Cyanamid."

In 1991 Immunex received FDA approval for Leukine foraccelerating marrow engraftment following autologous bonemarrow transplantation to treat certain cancers, and to extendsurvival of patients whose bone marrow transplants havefailed. Immunex said it expects to file a product licenseamendment with the FDA later this week for expanded use ofGM-CSF.

Immunex's stock (NASDAQ:IMNX) gained $1.50 a share onMonday, to close at $45.50.

-- Jennifer Van Brunt Senior Editor

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