Cytel Corporation Receives Patent for VLA-4 Integrin Blocking Compounds; Notice of Allowance Received for VLA-4 Inhibiting Antibodies.

SAN DIEGO--(BW HealthWire)--Jan. 9, 1998--Cytel Corporation (NASDAQ:CYTL) today announced it has received a patent from the United States Patent and Trademark Office (No. 5,688,913) for a series of peptidomimetic compounds that inhibit VLA-4 integrin receptor binding associated with chronic inflammatory diseases. In addition, the Company has received a Notice of Allowance (NOA) on a patent for which it has an exclusive worldwide license from the Fred Hutchinson Cancer Research Center. This NOA covers the use of antibodies directed at VLA-4 to treat or prevent inflammation. Compounds that block VLA-4 binding may be useful as therapeutics to treat chronic inflammatory diseases such as asthma, multiple sclerosis, and rheumatoid arthritis, according to Robert Roe, M.D., Cytel's Executive Vice President and Chief Operating Officer.

"Our VLA-4 patent position is very strong, encompassing small molecule and antibody compounds as integrin blockers," said Roe. "The pre-clinical data we have obtained for our compounds has been promising. We believe that they may have the potential for bronchial and oral activity, a key benefit in treating chronic conditions."

Cytel compounds block the VLA-4 white blood cell receptor site thereby preventing the migration of white blood cells through vessel walls and into tissues. The Company has performed numerous pre-clinical studies with these compounds in asthma, transplantation, arteriopathy, and multiple sclerosis models with encouraging results.

"This research area is a growing part of our focus on the inhibition of cell adhesion molecules to treat inflammatory diseases," added Roe. "We recently announced that clinical registration trials have been initiated for our lead cell adhesion compound, Cylexin, which is a selectin inhibitor. During the coming year, we will be conducting more advanced studies on VLA-4 blockers and will be identifying compounds to take into clinical development."

Cytel initiated a Phase II/III clinical registration trial of Cylexin(TM) in December 1997. Cylexin is designed to treat acute inflammatory responses and is currently in development for the treatment of reperfusion injury in infants undergoing hypothermic cardiopulmonary bypass during surgical repair of congenital heart defects.

White blood cells are a part of the human immune system and initiate the immune response by adhering to and destroying foreign invaders or diseased tissues. Chronic inflammatory diseases are triggered by the migration of white blood cells into healthy organs or tissues thus leading to an undesired immune response. Integrins are a group of adhesion receptors located on the surface of white blood cells responsible for the binding of these cells to tissue cells. VLA-4 appears to be the most relevant integrin receptor site associated with the migration of white blood cells into tissues. Thus, VLA-4 integrin receptor blockers can theoretically inhibit the primary step in the cell adhesion process that initiates the inflammatory cascade of events resulting in immunoinflammatory diseases.

Cytel is a leader in the discovery and development of cell adhesion inhibitors for treatment of acute and chronic inflammation, and its Glytec unit is a leader in the manufacture of bioactive carbohydrates for use in pharmaceutical 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.

CONTACT: Cytel Corporation, San Diego

Robert Roe, M.D., 619/552-3000

Executive Vice President and Chief Operating Officer

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Linda Seaton, 619/455-5500 ext. 133

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Mentus, Inc. (Investor Contact)

Virginia Rybski, 619/455-5500 ext. 113