Cytel Corporation Receives Patent for Improved Carbohydrate Synthesis Technology.

SAN DIEGO--(BW HealthWire)--May 19, 1998--Cytel Corporation (NASDAQ:CYTL) today announced it has received a patent from the United States Patent and Trademark Office (No. 5,728,554) for an improved carbohydrate synthesis method based on its proprietary Sugar Nucleotide Cycling(TM) (SNC) technology. The patent covers a novel method of controlling enzymatic reactions, resulting in increased yields of specialized carbohydrates approaching 100%.

"This patent represents an important increase in the coverage of our SNC technology," said Virgil Thompson, Cytel's president and chief executive officer. "Traditionally, it has been very difficult to work with carbohydrates due to the high cost associated with producing these complex compounds. With this exclusive technology, Cytel is capable of providing these specialized molecules more cost effectively."

The patent specifically covers the enzymatic synthesis of oligosaccharides (complex carbohydrates) using specialized recombinant enzymes called glycosyltransferases. These enzymes have the ability to form the appropriate chemical linkages necessary in creating tailor-made carbohydrate products.

"SNC is a powerful proprietary technology, enabling large-scale and highly specific carbohydrate production," said Jim Paulson, chief scientific officer and general manager of Glytec(TM). "Our Glytec business unit specializes in manufacturing carbohydrates for corporate partners seeking to accelerate development of new drug targets or novel consumer products. We are pleased to add to and protect this unique technology."

Sugar Nucleotide Cycling(TM) technology is used for the assembly of complex and specific bioactive carbohydrates on a commercial scale and is also useful for synthetic remodeling of carbohydrates or recombinant glycoproteins. The technology imitates the natural carbohydrate synthesis process requiring a cascade of chemical reactions initiated by specialized enzymes. The method is more time and cost effective than other chemical synthesis technologies.

Cytel discovers and develops cell adhesion inhibitors for treatment of acute and chronic inflammation, and manufactures bioactive carbohydrates for use in medical and consumer products. Epimmune Inc., its subsidiary, is focused on the discovery and development of a new generation of safer, more potent vaccines for the prevention and treatment of cancer and infectious diseases. -0-

This press release includes forward-looking statements that reflect management's current views of future events. Actual results may differ materially from the above forward-looking statements due to a number of important factors, including but not limited to the risks associated with successfully negotiating and completing definitive agreements for any corporate collaboration, the timing and cost of conducting human clinical trials, the regulatory approval process, and the possibility that testing may reveal undesirable and unintended side effects or other characteristics that may prevent or limit the commercial use of proposed products. These factors are more fully discussed in Cytel's most recent Forms 10-K and 10-Q.

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