News Release

Ribozyme Pharmaceuticals, Inc. Demonstrates Potent Activity Of A Ribozyme Targeted Against The Hepatitis C Virus

Peer-Reviewed Publication

Noonan/Russo Communications

Presented at Amer. Assoc. for the Study of Liver Diseases Conference

BOULDER, Colorado, November 9, 1998 -- Ribozyme Pharmaceuticals, Inc. (RPI) (Nasdaq: RZYM) today announced that HEPTAZYME®, a ribozyme designed to selectively destroy Hepatitis C Virus (HCV) RNA, was effective in decreasing Hepatitis C Viral RNA in cell culture assays. This work was presented at the American Association for the Study of Liver Diseases (AASLD) conference in Chicago by Dr. Lawrence Blatt, RPI's Senior Director of Biopharmacology and Preclinical Research. In these studies, HEPTAZYME® demonstrated significant inhibition of the HCV viral translation process in cells at very low doses, and in a manner that implies applicability across multiple forms of the virus.

Hepatitis C Virus (HCV) is the most common chronic bloodborne infection in the United States today. A recent Centers for Disease Control report stated that over 4 million Americans are chronically infected with HCV, and it is estimated that 500 million people are infected with HCV worldwide. The disease, which is more common than HIV, kills 8,000-10,000 Americans annually, and the death toll is expected to triple over the next 10-20 years. Furthermore, development of effective treatments has been hampered by the presence of multiple forms of HCV, with at least six genotypes and more than 90 subtypes known.

HEPTAZYME® contains many novel features believed to be important for HCV treatment. First, HEPTAZYME® is a ribozyme, a catalytic RNA molecule that has the unique potential to bind and cleave HCV RNA specifically and selectively, thus suggesting that viral replication can be inhibited without affecting other normal physiological processes. Next, HEPTAZYME® cleaves the HCV RNA at a location that is completely conserved in all known genotypes and subtypes of HCV, which gives HEPTAZYME® the potential to inhibit all forms of the virus. Finally, since HCV replicates in the cytoplasm and does not integrate into the genome, destruction of HCV RNA by HEPTAZYME® may allow cellular elimination of the virus.

"These novel compounds are targeted against the highly conserved regions of the HCV genome and thus have the potential to act directly by cleavage of the HCV RNA, and indirectly by selection for viral strains that cannot replicate. This represents a completely novel and potentially effective strategy to treat the millions of Americans afflicted with this disease," said Myron J. Tong, Ph.D., M.D., Professor of Medicine, University of Southern California, and Chief of the Liver Center, Huntington Memorial Hospital, Pasadena, California.

"The positive cell culture results with HEPTAZYME® are very encouraging and take RPI one step closer to providing an effective treatment for the HCV silent epidemic. Furthermore, the potential of HEPTAZYME® to be effective against multiple forms of HCV adds significantly to its potential as a therapeutic agent against HCV. We look forward to developing HEPTAZYME® aggressively, and hope that it will become an important component in anti-HCV treatment regimens," said Dr. Ralph Christoffersen, Ph.D., CEO and President of RPI.

RPI, located in Boulder, Colorado, was founded to capitalize on the broad potential of ribozymes for use as human therapeutics and other areas, including the identification of gene function and therapeutic target validation. RPI is developing an anti-angiogenesis compound ANGIOZYME® that is in Phase I Clinical Trials. The Company has also entered into a collaboration with Chiron Corporation to develop ribozyme therapeutics, including an HIV product in Phase II clinical trials. It has entered into therapeutic target validation and discovery collaborations with Schering AG (Germany), Chiron, Parke-Davis, Roche Bioscience and GlaxoWellcome, and has formed Atugen Biotechnology GmbH in Berlin to encompass these activities in the future. It has additional collaborations with DowElanco for commercialization of certain ribozyme-based agricultural products; with Pharmacia Biotech AB on the production-scale synthesis of modified RNA components; with Protogene Laboratories to develop automated equipment for large scale production of ribozymes; and with IntelliGene Corporation for development of ribozyme-based diagnostics.

This press release contains forward-looking statements that involve risks and uncertainties, and actual events or results may differ materially. These risk factors include actions by the U.S. Food and Drug Administration, technological advances, ability to commercialize and manufacture products and general economic conditions. These and additional risk factors are identified in our annual report to the Securities and Exchange Commission filed on forms 10-KSB and in other SEC filings.

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Contacts:

Ribozyme Pharmaceuticals, Inc.
Ralph E. Christoffersen, Ph.D.
CEO and President
303-449-6500

Noonan/Russo Communications, Inc.
Neil Cohen (media)
415-677-4455, ext. 205
Stephanie Seiler (investors)
212-696-4455, ext. 212



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