Chiron Corp. and its partner Novo Nordisk A/S on Tuesdayreceived a U.S. process patent that Chiron said has broadapplicability to the manufacture of recombinant Factor VIII:C.

Factor VIII, which is currently derived from plasma, is used totreat hemophilia. But plasma-derived Factor VIII carries therisk of disease from infectious agents in the original source,is expensive and limited in supply.

Patent No. 5,045,455 covers a gene for one of the two subunitsnecessary for recombinant expression of Factor VIII:C. Thepatent claims cover an intron-free DNA molecule that encodesthe heavy chain of Factor VIII:C. An intron is a non-codingsequence separating coding regions of genes.

Chiron described the other key subunit, called the light chain,in its patent application, but didn't claim it in order tosimplify the patent application process, said Robert Blackburn,director of intellectual property at the Emeryville, Calif.-based company.

Because the heavy chain gene is included in all first- andsecond-generation recombinant Factor VIII products, Chironsaid it expects that any companies intending to manufactureand market recombinant Factor VIII:C will be required tolicense the patent before they can sell the products in theUnited States.

Miles Laboratories, using technology licensed from GenentechInc., and Baxter Laboratories, using technology licensed fromGenetics Institute Inc., each have applied to the Food and DrugAdministration to market recombinant Factor VIII:C. Anothercompany hoping to produce recombinant Factor VIII is RorerGroup Inc.

Blackburn said Chiron's new patent doesn't overlap with anyissued Factor VIII patents.

Genetics Institute of Cambridge, Mass., has a patent to a DNAmolecule that encodes all of Factor VIII, said Blackburn.Genentech of South San Francisco, Calif., has applied for apatent that is currently in interference proceedings with GI'spatent at the Patent and Trademark Office.

All three biotech companies are in litigation with ScrippsClinic, which holds a patent on the natural Factor VIII proteinand claims that the three companies are infringing it throughtheir production of recombinant Factor VIII. The U.S. Court ofAppeals in March sent the case back for trial. No date has beenset.

Chiron stock (NASDAQ:CHIR) closed up 50 cents on Tuesday at$58.

-- Karen Bernstein BioWorld Staff

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