Hemispherx Presents Evidence of Ampligen(R) Synergies with Existing Antivirals at International Avian Influenza Conference.

Ampligen[R] Potentiates the Inhibition of Avian Flu by Oseltamivir (Tamiflu) or Zanamivir (Relenza)

PARIS -- Hemispherx Biopharma, Inc. (AMEX: HEB), a biopharmaceutical company engaged in the clinical development of new drug entities for the treatment of pandemic disease threats, announced today a new scientific report on the activity of its experimental therapeutic Ampligen([R]) in combination with approved anti-influenza agents against highly pathogenic avian influenza (HPAI), also known as bird flu.

Tamiflu resistance by newly emerging strains of HPAI has been widely reported (New Engl. Journal Medicine vol. 353: page 2667, 2005) and has provided impetus for new ways to implement an antiviral counter-attack strategy.

In in vitro studies, Ampligen([R]), an experimental therapeutic, was combined with the neuraminidase inhibitors Oseltamivir, (brand name Tamiflu) and with Zanamivir (Relenza) and thereafter applied to cells in culture infected with an H5N1 strain of HPAI. Three days following infection, cell viability and synergy analyses were performed.

Both Ampligen([R]) and the neuraminidase inhibitors exhibited dose responses in the inhibition of the adverse effects of HPAI on cell cultures. Moreover, the combination of Ampligen([R]) with oseltamivir at doses exceeding a certain threshold showed synergistic inhibition of viral induced cell destruction, and similar synergistic results were seen with the combination of Ampligen([R]) with zanamivir.

The study results are being presented at the ongoing 2nd International Conference on Avian Influenza, being held at the Pasteur Institute.

While it is widely recognized that HPAI is a major, global public health concern, existing antiviral monotherapies can rapidly lead to drug-resistant strains of virus. Therefore, the Hemispherx study was conducted to establish a potentially pivotal role for Ampligen as part of a potentially effective combination therapy. Ampligen([R]) is a novel double-stranded RNA experimental therapeutic that exhibits antiviral activity by different mechanisms than either Tamiflu or Relenza; it has completed Phase III clinical testing for another disorder, Chronic Fatigue Syndrome (CFS).

"With so few lines of defense currently available against avian influenza, it is crucial to discover lasting ways to extend and enhance the effectiveness of existing therapies, as has been done historically with other devastating viral diseases including HIV/AIDS and hepatitis," commented Dr. William Carter, Chairman and Chief Executive Officer of Hemispherx. "We are pleased to share the results of our studies of combination therapies involving Ampligen([R])and look forward to accelerating this development program under the "animal rule" for fast tracking experimental therapeutics for life threatening disorders." Under the "animal rule," extensive clinical studies can be replaced by animal model studies to evaluate efficacy under certain circumstances.

About Hemispherx Biopharma

Hemispherx Biopharma, Inc. is a biopharmaceutical company engaged in the manufacture and clinical development of new drug entities for treatment of seriously debilitating disorders. Hemispherx's flagship products include Alferon N Injection[R] and the experimental therapeutics Ampligen[R] and Oragens[R]. Alferon N Injection[R] is approved for a category of STD infection, and Ampligen[R] and Oragens[R] represent experimental RNA nucleic acids being developed for globally important viral diseases and disorders of the immune system. Hemispherx's platform technology includes large and small agent components for potential treatment of various severely debilitating and life threatening diseases. Hemispherx has in excess of 100 patents comprising its core intellectual property estate, a fully commercialized product (Alferon N Injection[R]) 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], Alferon LDO and Oragens) 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 N Injection[R] do not imply that the product will ever be specifically approved commercially for these other treatment indications.