Isis Pharmaceuticals Inc. announced Tuesday that it willreceive its U.S. patent on antisense oligonucleotide inhibitors ofHIV. Patent No. 5,166,195 covers phosphorothiateoligonucleotide compositions designed to selectively bind toRNA encoding the HIV tat protein (trans-activator), whose roleis to stimulate transcription. Thus, the antisense constructsblock replication of the virus and the 5' leader sequence.

"The tat protein ... is crucial in the life cycle of the AIDS virus,"said Christopher Mirabelli, Isis' senior vice president. "The 5'leader sequence is important because it is present on all HIVtranscripts."

The patent also covers pharmaceutical compositions containingthese oligonucleotides, the Carlsbad, Calif., company(NASDAQ:ISIP) said.

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