Enzon Inc. has signed a letter of intent for use of its antigenbinding technology with Neoprobe Corp.'s RadioImmunoguidedSurgery technology to treat cancer.

Enzon's single-chain antigen-binding proteins consist of a wholechain of an antibody and have a higher affinity for their targetsthan either whole antibodies or antibody fragments, said GlennKazo, vice president of corporate development at Enzon(NASDAQ:ENZN).

Their high binding rates give SCAs a short circulating life,which ought to reduce the chances of immune responses, Kazosaid. SCAs haven't been tested in humans yet.

Neoprobe's RIGS system assists surgeons in locating andremoving cancerous tissue. The system combines a cancer-specific antibody -- in this case an SCA -- with a low-energyradioisotope and a hand-held gamma ray detection probe.

The privately held Columbus, Ohio, company's first antibody-based product is entering Phase II trials for colon and rectalcancer.

Enzon will take a Neoprobe antibody and modify it to form anSCA. The licensing arrangement will include an up-front fee,milestone payments and royalties. Terms haven't beendisclosed.

SCAs were developed by Genex Corp., which Princeton, N.J.-based Enzon acquired in November. Last August, Genex won apatent interference dispute against Creative BioMolecules Inc.

Enzon shares closed at $16, up 50 cents, on Friday. -- KB

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