3 New Studies Show Hemispherx Biopharma's Ampligen(R) and Alferon(R) LDO May Provide Defense against Avian Flu.

PHILADELPHIA -- Hemispherx Biopharma, Inc. (AMEX: HEB):

--Tests Indicate Potential of Ampligen(R) As Vaccine Adjuvant, Boosts Existing Drugs Tamiflu(R), Relenza(R) Up To 100 Times; Alferon(R) LDO Found to Stimulate Production of Interferon, Offering Natural Defense Against Virus

--Consortium of Researchers to Present Findings at Today's ASM Biodefense Research Meeting in Washington, D.C.

Hemispherx Biopharma, Inc. (AMEX: HEB), a leader in the clinical development and production of new drug entities for the treatment of viral and immune-based chronic disorders, today unveiled the results of laboratory testing that shows its two investigational immunotherapeutics, Ampligen(R) and Alferon(R), are potentially useful against the H5N1, or avian flu, virus. The pre-clinical research indicates that Ampligen(R), a specifically configured double-stranded RNA, can provide cross-protection against avian flu viral mutations as well as boost the effectiveness of Tamiflu and Relenza, the only two drugs formally recognized for combating bird flu, up to 100 times. Other lab tests, in healthy human volunteers, indicate that Alferon(R) LDO (Low-Dose Oral), a new delivery form of an anti-viral with prior regulatory approval for a category of sexually transmitted diseases, can stimulate genes that induce the production of interferon and other immune compounds, key building blocks in the body's defense system. Hemispherx Biopharma and collaborating government scientists are presenting detailed findings at today's American Society for Microbiology Biodefense Research Meeting in Washington, DC.

The results of an animal study conducted by Dr. Hideki Hasegawa, M.D., Ph.D., Chief, Laboratory of Infectious Disease Pathology at the National Institute of Infectious Diseases in Tokyo, reveal that Ampligen(R) boosts IgA antibody levels by up to 500% when co-administered with vaccine--the exact antibodies that protect mucosal membranes of the nose and mouth, the specific entry points of an invading avian flu virus. In the course of the research, animals that were internasally administered with the vaccine Ampligen(R) registered an increase in antibodies that could fight the deadly virus. Some 80% of the Ampligen(R)-treated mice survived the virus's onslaught, while none survived in a corresponding placebo group.

"As indicated in earlier peer-review reports, double-stranded RNA proved to be the most effective adjuvant for our nasal vaccine, and our new research reveals that Ampligen(R) is the only non-toxic dsRNA that's applicable to humans," said Dr. Hasegawa. "In addition, the alternative method of delivery used in this study--nasal mist--also has potential value. The tests suggest that not only does Ampligen(R) have the potential to be an effective therapy against the virus by itself, but also that the nasal mist method is far more economical, requiring only 1/20th of the injection dosage. This means we can substantially expand the supply and availability of this drug, and treat more people quickly and effectively."

Independent lab research conducted at Utah State University under U.S. National Institutes of Health (NIH) sponsorship indicates that Ampligen(R) increases the efficacy of the two viral uptake inhibitors, Tamiflu and Relenza. The lab studies suggest that 50 to 100 times less Tamiflu may be used in conjunction with the experimental immunotherapeutic Ampligen(R) to achieve full inhibition with no multiplication of the virus, and no host cell damage. This may be a critical factor not only because of the potential shortage of Tamiflu, but also because 18% of all children are resistant to Tamiflu at conventional doses (as reported in the New England Journal of Medicine, December 2005). The effect was found be even stronger with Relenza (up to 500-fold potentiation) in the lab experiments.

The experimental immunotherapeutic Alferon(R) N Injection is derived from an FDA-approved treatment for the Human papillomavirus (HPV, or genital warts). Hemispherx Biopharma has developed an oral delivery format for the product that requires much lower doses, called Alferon(R) LDO; new tests conducted in collaboration with the Cleveland Clinic suggest it may stimulate a large bank of anti-viral immune genes that may control the body's production of interferon and thereby potentially fight a wide range of diseases, including avian flu.

"This is the race we have to win--to sufficiently mobilize the interferon system early enough so that it will knock out the virus multiplication," said Professor Luc Montagnier, President of the Foundation for AIDS Research and Prevention, who is widely credited with discovering the AIDS virus, HIV. "I believe that in addition to the anti-viral effect, Alferon(R) LDO will mobilize another important component of innate immunity, cells able to eliminate infected cells. It will act both on the native avian virus and on its humanized form."

Results from Phase 1/Phase 2 clinical trials in healthy volunteers, being conducted at the Princess Margaret Hospital in Hong Kong indicate that Alferon(R) LDO may strengthen human immune responses via interferon-activated genes, potentially staving off infection should an individual be thereafter exposed to the virus. By priming the body's own interferon pump, Alferon(R) LDO might enable an infected host to produce enough interferon to overcome the virus. The studies being reported today include specific markers of immune response following exposure to Alferon(R) LDO in the absence of any viral exposure.

"Given the potential for a pandemic, these results may have significant implications for control of the avian flu virus," said William A. Carter, M.D., Chairman and CEO of Hemispherx Biopharma. "In relevant animal models and human volunteer studies, both experimental immunotherapeutics, Ampligen(R) and Alferon(R) LDO may trigger the production of novel defense products as part of the body's immune system. Therefore, we are encouraged that these experimental immunotherapeutics represent a significant new path forward in potential preparation against the global spread."

Hemispherx Biopharma intends to file a new drug application (NDA) for Ampligen(R) as a treatment for Chronic Fatigue Syndrome later this year. Since Alferon(R) N Injection is already FDA-approved, Hemispherx Biopharma would file various amendments globally to its existing approval licenses, reflecting a different method of delivery and different efficacy data on any potentially new therapeutic applications, including 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 Biopharma's flagship products include Alferon(R) and the experimental immunotherapeutics/antivirals Ampligen(R) and Oragens(TM). Alferon(R) is approved for a category of STD infection, and Ampligen(R) and Oragens(TM) represent experimental 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 chronic viral infections. Hemispherx has in excess of 140 patents comprising its core intellectual property estate, a fully commercialized product (Alferon(R) N) and GMP certified manufacturing facilities for its novel pharma products. For more information please visit www.hemispherx.net

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(R) 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(R) do not imply that the product will ever be specifically approved commercially for these other treatment indications.