Enzon Inc. announced Tuesday that it reached a full-licensingagreement with Neoprobe Corp. The deal gives Neoprobeexclusive worldwide rights to apply Enzon's single-chain,antigen-binding (SCA) technology to Neoprobe'sradioimmunoguided surgery (RIGS) for the treatment of cancer.

Under the agreement, South Plainfield, N.J.-based Enzon willreceive up-front and milestone payments totalling $1.7 millionfor the first product developed, and $1.1 million for eachsubsequent product, plus royalties on product sales.

SCA proteins, developed by Genex Corp. and acquired by Enzonin November 1991, provide the binding specificity and affinityof conventional antibodies, but in a smaller form. They mayenhance performance in diagnostic, therapeutic and separationapplications for which conventional antibodies are now used.

Combining a cancer-specific monoclonal antibody, a low-energyradioisotope and a patented hand-held gamma ray detectionprobe, the RIGS system helps surgeons find tumor cells thatmay have been missed and assess the extent of the disease.

"We believe that the single-chain form is the best approach toutilizing monoclonal antibodies," said Douglas Hulse, Enzon'svice president of business development.

Studies conducted by Enzon and the National Cancer Institutehave shown that the CC49 SCA protein may localize to tumorsmore quickly than the CC49 monoclonal antibody. This couldallow the RIGS procedure to be performed much sooner afteradministration of the SCA protein than the conventionalmonoclonal antibody.

David Bubb, president and chief executive of Columbus, Ohio-based Neoprobe, declined to comment on the company's plansfor the combination technologies, but Enzon's Hulse said hebelieves Neoprobe is currently in Phase II trials, using an intactmonoclonal antibody. He said the SCA application will probablyfollow with an evaluation of the CC49 antibody in the SCA formbeing the first step in the process. -- Michelle Slade

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