Ampligen (R) Enhances the Effectiveness of Tamiflu Against Avian Influenza; Second Independent Preclinical Study Confirms dsRNA Increases Flu Vaccine Effectiveness.

PHILADELPHIA -- Hemispherx Biopharma, Inc. (AMEX: HEB) today reported two new preclinical studies on double-stranded RNA (dsRNA), including Ampligen(R), one of its flagship experimental immunomodulators. Both preclinical studies suggest a new, and potentially pivotal, role of dsRNA therapeutics in improving the efficacy of the present standards of care in both influenza prevention and treatment of acute disease.

The first preclinical report, conducted by research affiliates of the National Institutes of Health at Utah State University, compared the relative protection conveyed by Tamiflu (oseltamivir, Roche) and Ampligen(R) (dsRNA, Hemispherx), alone and in combination against the avian flu virus (H5N1). Cell destruction was measured in vitro using different drug combinations. Both drugs, given alone, were effective in inhibiting cell destruction by avian influenza, but viral "suppression with the combination was greater than either drug alone". The researchers reported, in summary; "The overall assessment is that there was improvement in cell protection when Ampligen(R) was combined with oseltamivir carboxylate" (Tamiflu). Further immediate experimental tests are planned.

At present, a narrow window of opportunity (approximately 48 hours) exists for effective utilization of Tamiflu after exposure to influenza. By providing a new mechanism of inhibition of avian flu, (i.e. immunologic/host defensive immune cascades), Ampligen(R), an experimental immunotherapeutic, may afford a new approach to help combat influenza virus.

Double-stranded RNA (dsRNA), such as Ampligen(R), are also specific inducers of broad-spectrum antiviral/immune response. Recently, Japanese researchers (Journal of Virology page 2910, 2005) have also found that dsRNA's increase the effectiveness of influenza vaccine by more than 300% and may also convey "cross-protection ability against variant viruses" (mutated strains of influenza virus). Ampligen(R) recently completed Phase III testing in the chronic disease, Chronic Fatigue Syndrome (CFS).

Hemispherx Biopharma recently disclosed in a letter to shareholders (September 1, 2005) that it has increased the capacity of its facility in New Brunswick, NJ to manufacture Ampligen(R) , as well as advancements in the application of Alferon LDO for potential treatment of avian flu.

About Hemispherx Biopharma

Hemispherx Biopharma, based in Philadelphia, is a biopharmaceutical company engaged in the manufacture and clinical development of new drug entities for treatment of viral and immune-based chronic disorders. Hemispherx's flagship products include Alferon and the experimental immunotherapeutics/antivirals Ampligen(R) and Oragens(TM). Alferon is approved for a category of STD infection, and Ampligen(R) and Oragens(TM) represent experimental nucleic acids being developed for globally important chronic viral diseases and disorders of the immune system including HPV, HIV, CFS, Hepatitis. Hemispherx's platform technology includes large and small agent components for potential treatment of various chronic viral infections. Hemispherx has in excess of 140 patents comprising its core intellectual property estate, a fully commercialized product (Alferon N) and GMP certified manufacturing facilities for its novel pharma products. For more information please visit www.hemispherx.net

Information contained in this news release other than historical information, should be considered forward-looking and is subject to various risk factors and uncertainties. For instance, the strategies and operations of Hemispherx involve risk of competition, changing market conditions, change in laws and regulations affecting these industries and numerous other factors discussed in this release and in the Company's filings with the Securities and Exchange Commission. Any specifically referenced investigational drugs and associated technologies of the company (including Ampligen(R) and Oragens(TM)) are experimental in nature and as such are not designated safe and effective by a regulatory authority for general use and are legally available only through clinical trials with the referenced disorders. The forward-looking statements represent the Company's judgment as of the date of this release. The Company disclaims, however, any intent or obligation to update these forward-looking statements. Clinical trials for other potential indications of the approved biologic Alferon(R) do not imply that the product will ever be specifically approved commercially for these other treatment indications.