Immunex Corp. stock lost $2 on Thursday, closing at $39.75,amid conflicting estimates of its share of the GM-CSF marketand ethical concerns about a long-term purchasing agreementwith American Healthcare Systems.

Oppenheimer & Co. analyst Jeffrey Casdin wrote that Immunexappeared to be losing market share to Hoechst AG, its co-marketing partner for granulocyte-macrophage colonystimulating factor, and that the deal with AmHS appeared to beaimed at stemming the erosion.

Emphasizing that his numbers were preliminary, Casdin saidthat Hoechst's Prokine could now be running neck and neck withImmunex's Leukine. Casdin estimated that Immunex's grossmargins are 80 percent on Leukine sales vs. 25 percent onProkine sales.

Immunex spokesman Jason Rubin said Casdin was relying onincomplete data. Rubin said sales were running 2-to-1 in favorof Leukine based on the Seattle company's analysis of severalindustry databases.

Casdin and Montgomery Securities analyst Brandon Fradd bothexpressed ethical concerns about the inclusion of an equityinterest in the deal between Immunex and AmHS for thepurchase of Leukine. Physicians might be induced to use moreof a particular product if it could generate a capital gain forthe hospital, Casdin wrote.

The deal, announced last Friday, gives AmHS warrants topurchase 100,000 shares of Immunex stock (NASDAQ:IMNX),plus a possible additional 150,000 warrants based on thepercentage of GM-CSF purchased from Immunex rather thanfrom other companies over the next five years. The totalwarrants available to AmHS represent 1.3 percent of fullydiluted Immunex shares outstanding.

Fradd told BioWorld that he was less concerned now thatImmunex has clarified the small number of warrants involved.He said the agreement could enhance Immunex's earningsprospects. -- Karen Bernstein

-- Karen Bernstein BioWorld Staff

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