Immunex Corp. stock lost $3.50 on Thursday, closing at $47.50,after Oppenheimer & Co. analyst Jeffrey Casdin said he wasmaintaining his "trading sell" on the Seattle-based company.

Immunex (NASDAQ:IMNX) had gained $4.75 on Wednesday afternews that the Patent and Trademark Office might not issue apatent on granulocyte macrophage colony stimulating factor(GM-CSF), a white blood cell stimulator. Genetics Institute Inc.and Immunex have patent applications in interference at thePTO.

Wrote Casdin, "(We) do not believe the recent GM-CSF patentnews is particularly positive for Immunex since it potentiallyturns the product into a generic, clipping its upside valueshould it become something significantly more than themodest product it is today. We see no signs that it will be."

GI has a good chance of winning a patent, he said, especiallysince it recently received a patent in Europe, where it isharder to obtain the claims being contested at the PTO.

Casdin added that while Immunex has potentially excitingproducts in its pipeline, they are impossible to value withoutclinical data. Absent that, he concluded that "it is hard tojustify a valuation above $35 per share." -- KB

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