Nastech Pharmaceutical Company Inc. Presents Successful In Vitro And In Vivo Results With Its RNAi Therapeutics Program For Influenza

BOTHELL, Wash., March 16 /PRNewswire-FirstCall/ -- Nastech Pharmaceutical Company Inc. , a leader in developing therapeutics using advanced molecular biology based drug delivery technologies, announced today the presentation of results demonstrating the effectiveness of the Company's small interfering RNA (siRNA) therapeutics to broadly target and inhibit influenza viral production at the 8th International Symposium on Respiratory Viral Infections Conference.

In vitro and in vivo results were presented for siRNAs that are specifically designed to target conserved regions of the influenza viral genome. We believe that targeting the conserved regions could enable a siRNA therapeutic to be effective against both current and future strains of the influenza virus, which is essential in stockpiling a treatment for rapid mobilization during an influenza pandemic. In vitro screening results identified highly potent siRNAs with IC50 values between 20 and 500 pM that were effective against representative human and avian influenza strains, including H5N1 avian influenza virus.

Furthermore, in vivo results demonstrate that direct-to-lung and intravenous administrations of selected proprietary formulations of siRNAs effectively inhibit influenza viral production in a preclinical model. A 200-fold reduction of viral concentration in the blood was observed.

"Nastech's goal is to rapidly develop a safe and effective treatment that is broadly applicable against current and future influenza strains so that the medical community can be better prepared for an influenza pandemic, which has become an impending threat to worldwide public health," stated Steven C. Quay, M.D., Ph.D., Chairman, President and CEO of Nastech. "The results presented by Nastech demonstrate the effective inhibition of influenza virus production by a siRNA therapeutic and further validate Nastech's advanced delivery technology and siRNA therapeutic development capabilities."

About Influenza

According to the World Health Organization (WHO), in a typical year, influenza infects 5 - 15% of the world's population, resulting in 250,000 to 500,000 deaths. The WHO and the Centers for Disease Control and Prevention are concerned about the potential for a major global pandemic such as the 1918 "Spanish flu" in which up to 50 million people may have died worldwide. Pandemic flu emerges from a sudden change in the influenza virus that results in a new flu strain, against which there is no immunity. Vaccines currently represent the mainstay of flu prevention, but vaccines have two key limitations. First, they are developed against individual, known strains of flu and therefore may not be effective against new flu strains. Second, vaccines are produced using a lengthy process requiring incubation in chicken eggs, thus vaccine against a new flu strain will take months or years to stockpile. Antiviral medications approved to treat influenza have the potential drawback that influenza virus strains can become resistant to one or more of these medications. The potential advantage of RNAi antiviral therapeutics is that siRNA can be targeted against the conserved region of the influenza virus. This means that an RNAi therapeutic would be expected to be effective against all strains of the influenza virus, whether new or old. Therefore stockpiling of an effective RNAi treatment is possible in advance of a global influenza pandemic. In addition to a potential role in a pandemic flu outbreak, RNAi therapeutics could serve as a treatment for the more common seasonal flu that as noted above can result in hospitalization and death.

About RNA Interference (RNAi)

RNA interference, or RNAi, is a cellular mechanism that can be used to turn off the production of a protein. In the case of an RNAi directed against influenza, the target is one or more proteins critical for viral replication. By turning off the production of such proteins, the spread of infection is prevented or slowed. Nastech's RNAi research and development programs seek to develop safe and effective therapeutics by identifying key protein targets, designing the siRNA that will turn off the production of the targeted proteins, and developing a formulation for the systemic delivery of this potential new class of therapeutics.

About Nastech

Nastech is a pharmaceutical company developing innovative products based on proprietary molecular biology-based drug delivery technologies. Nastech and our collaboration partners are developing products for multiple therapeutic areas including respiratory disease, inflammatory conditions, obesity and osteoporosis. Additional information about Nastech is available at http://www.nastech.com.

Nastech Forward Looking Statements

Statements made in this press release may be forward-looking statements within the meaning of Federal Securities laws that are subject to certain risks and uncertainties and involve factors that may cause actual results to differ materially from those projected or suggested. Factors that could cause actual results to differ materially from those in forward-looking statements include, but are not limited to: (i) the ability of Nastech to obtain additional funding; (ii) the ability of Nastech to attract and/or maintain manufacturing, research, development and commercialization partners; (iii) Nastech's and/or a partner's ability to successfully complete product research and development, including preclinical and clinical studies and commercialization; (iv) Nastech's and/or a partner's ability to obtain required governmental approvals; and (v) Nastech's and/or a partner's ability to develop and commercialize products that can compete favorably with those of competitors. Additional factors that could cause actual results to differ materially from those projected or suggested in any forward-looking statements are contained in Nastech's most recent periodic reports on Form 10-K and Form 10-Q that are filed with the Securities and Exchange Commission. Nastech assumes no obligation to update and supplement forward-looking statements because of subsequent events.

CONTACTS: Nastech Pharmaceutical Company Inc. Nastech Ed Bell Senior Investor Relations Manager (425) 908-3639 ir@nastech.com Noonan Russo Matthew Haines (Investors/Media) (212) 845-4235

Nastech Pharmaceutical Company Inc.

CONTACT: Ed Bell, Senior Investor Relations Manager of Nastech,+1-425-908-3639, ir@nastech.com; or Matthew Haines of Noonan Russo,+1-212-845-4235

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