By Lisa Seachrist

Washington Editor

The U.S. Patent and Trademark Office (PTO) issued a patent to Human Genome Sciences Inc. for the human gene that produces a protein receptor that serves as an entry point for the virus that causes AIDS.

The patent covers the gene known as CCR5 receptor gene, which is believed to be a critical entry point for the HIV. Just last week, HGS entered a collaboration with Praecis Pharmaceuticals, of Cambridge, Mass., to develop small-molecule drugs to battle AIDS using the CCR5 receptor gene.

The news of the patent sent HGS' stock (NASDAQ:HGSI) 21 percent higher on Wednesday to close at $188, up $33.25.

"This isn't simply an [expressed sequence tag] patent," said Craig Rosen, executive vice president of research and development for HGS, of Rockville, Md. "It's the full-length gene and we've added a lot of biology. We've filed over 7,000 patents. These are for real genes that have real importance to the medical community."

Rosen said the CCR5 gene patent demonstrates HGS has set about patenting useful genes. The company filed the patent in June 1995 because CCR5 proved to be a G-protein coupled receptor. Such receptors are found on the surface of cells and have proved exceptionally good targets for drugs. Allergy drug Claritin, the antacids Zantac, Tagamet and Pepcid, as well as the migraine medicine Imitrex are all aimed at affecting a G-protein coupled receptor of one sort or another.

HGS scientists have unearthed more than 66 novel members of this receptor class. Together with partners, the company has filed patents on these genes, and a total of 13 have been issued.

In 1996, National Cancer Institute researchers discovered HIV-infected patients with deletions in both copies of their CCR5 gene didn't develop the clinical symptoms of AIDS. This discovery indicates the receptor might be an effective target for an AIDS drug. (See BioWorld Today, Sept. 27, 1996, p. 1.)

HGS has provided several partners in addition to Praecis with a license to use the CCR5 gene in drug discovery.

HGS Chairman and CEO William Haseltine, in a news release, said: "The discovery of the CCR5 receptor gene is another example of the power of the genomics approach to drug discovery. It was one of many genes that we found very early in our discovery program. Experiments confirmed that the CCR5 receptor played a key role in the biology of the immune system and as an AIDS virus receptor."

Rosen said the receptor makes an ideal target for antibodies and small-molecule drugs. "We already have a program with antibodies under way," he said.