The European Patent Office has rejected a challenge to a patentcovering non-radioactively labeled nucleic acids that underliesmany of Enzo Biochem Inc.'s DNA-based probe products, Enzoannounced on Monday.

Amersham International plc lodged its opposition to Enzo'sEuropean Patent No. 0 063 879 last May, claiming that theinvention had already been disclosed in scientific literature,according to Enzo spokeswoman Carol Dempster. Enzo receivedthe patent in 1989.

With the decision, Enzo has full patent rights in Europe.

The Farmingdale, N.Y., company (AMEX:ENZ) has an exclusivelicense from Yale University to a U.S. patent for the sametechnology. U.S. patent No. 4,711,955, covering theincorporation of biotin labels in DNA, was issued in 1987.

The patent protects "the most fundamental aspects of non-radioactive detection technology for DNA probes," according toEnzo. The biotin label permits detection of nucleic acids withoutinterfering with their binding characteristics, according to thecompany.

Enzo's biotin label probes include Colorgene DNA HybridizationTest for herpes simplex virus confirmation; BioPapp (humanpapilloma virus tests for cervical smears); PathoGene (DNAprobe assays for various pathogens, including humanpapilloma, cytomegalovirus, herpes simplex, chlamydia andothers); and HIV Microplate Hybridization Assay.

Enzo stock gained 25 cents to $4.50 on Monday. -- Steve Usdin

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