Hemispherx Biopharma Reports New SARS Data on Alferon at the 14th International Antiviral Symposium.

Business Editors/Health/Medical Writers

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PHILADELPHIA--(BUSINESS WIRE)--Nov. 10, 2003

One of the Most Effective Antiviral Compounds Tested to Date Now

Becomes Lab Standard

Hemispherx Biopharma, Inc. (AMEX: HEB) announced today that at the 14th International Antiviral Symposium and Workshop in Antalya, Turkey, the Company reported data showing that Alferon N(R), the Company's lead drug, is highly active against SARS coronavirus.

Independent Funding by U.S. National Institutes of Health

These new results were obtained from a Research Project funded by the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under contract No. N01-AI-85348. Out of more then 150 compounds tested, Alferon N(R) represents one of the most effective compounds, showing high specific activity on the replication of human SARS coronavirus. The high activity establishes a new lab standard for SARS research. As a result of this study, Alferon N(R) has become the laboratory standard for testing on SARS of all other drugs in the Research Project.

About SARS

A new coronavirus (SARS-CoV) has been identified as the etiological agent in SARS. Although the epidemic was brought under control by epidemiological measures, the potential for a world pandemic in the future remains a significant treat to human health. The identification of compounds that inhibit SARS-CoV replication is a high international priority.

Experimental Tests Quantitatively Establish Alferon N's High In Vitro Potency Against SARS

The study shows that Alferon N(R), inhibits SARS-CoV at a high specific activity in Vero 76 cells (African green monkey) in culture. Inhibition was quantitated by visual cytopathic effect (CPE), inhibition of the cellular uptake of the vital dye, neutral red (NR), and by virus yield reduction. Fifty percent effective doses (EC50) were calculated for both CPE and NR assays by regression analysis. Quantitative values for viral yield reduction assays were expressed as 90% effective concentrations (EC90), representing the drug concentration required to reduce SARS-CoV titers by one log10 and were calculated by regression analysis. Vero cells infected at a MOI of 0.001 visually exhibited 100% CPE over a 3-5 day incubation period without treatment. Alferon N(R) inhibited SARS-CoV at an EC50=5,696 +/-1,703 (SEM) IU/ml (visual) and 10,740 +/-5,161 (SEM) IU/ml (NR). Viral load reduction by one log10 was 78,000 +/- 22,000 (SEM) IU/ml.

About Alferon N(R)

Alferon N(R) (Interferon alfa-n3, human leukocyte derived) is a highly purified, natural source, glycosylated, multispecies alpha interferon product, composed of eight forms of high purified alpha interferon. It is the only natural-source, multispecies alpha interferon currently sold in the U.S. for the treatment of refractory papilloma infections (HPV) and is also approved for sale by various regulatory agencies worldwide. By contrast, recombinant, non-natural source, interferon is composed of only one form and can cause allergic (antibody formation) reactions in man.

About Hemispherx

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. Its flagship products include Alferon and the experimental immunotherapeutics/antivirals Ampligen and Oragens. These novel proteins, approved for a category of STD infection, and experimental nucleic acids are being developed for globally important chronic viral diseases and disorders of the immune system including HPV, HIV, CFS and Hepatitis. Its platform technology includes large and small agent components for potential treatment of various chronic viral infections. Hemispherx has approximately 400 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. Only Clinical Studies under well-controlled conditions can establish efficacy and safety of any product. 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 including SARS. The Alferon(R) asset for overseas sales for a category of STD is currently being acquired by the Company as part of a multi-step purchase contract of inventory, intellectual property, commercial licenses and GMP approved facilities, which house the biological operations.