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

-- 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 clinicaldevelopment and production of new drug entities for the treatment ofviral and immune-based chronic disorders, today unveiled the resultsof laboratory testing that shows its two investigationalimmunotherapeutics, Ampligen(R) and Alferon(R), are potentially usefulagainst the H5N1, or avian flu, virus. The pre-clinical researchindicates that Ampligen(R), a specifically configured double-strandedRNA, can provide cross-protection against avian flu viral mutations aswell as boost the effectiveness of Tamiflu and Relenza, the only twodrugs 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 priorregulatory approval for a category of sexually transmitted diseases,can stimulate genes that induce the production of interferon and otherimmune compounds, key building blocks in the body's defense system.Hemispherx Biopharma and collaborating government scientists arepresenting detailed findings at today's American Society forMicrobiology 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 theNational Institute of Infectious Diseases in Tokyo, reveal thatAmpligen(R) boosts IgA antibody levels by up to 500% whenco-administered with vaccine--the exact antibodies that protectmucosal membranes of the nose and mouth, the specific entry points ofan invading avian flu virus. In the course of the research, animalsthat were internasally administered with the vaccine Ampligen(R)registered an increase in antibodies that could fight the deadlyvirus. Some 80% of the Ampligen(R)-treated mice survived the virus'sonslaught, while none survived in a corresponding placebo group.

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

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

The experimental immunotherapeutic Alferon(R) N Injection isderived from an FDA-approved treatment for the Human papillomavirus(HPV, or genital warts). Hemispherx Biopharma has developed an oraldelivery format for the product that requires much lower doses, calledAlferon(R) LDO; new tests conducted in collaboration with theCleveland Clinic suggest it may stimulate a large bank of anti-viralimmune genes that may control the body's production of interferon andthereby potentially fight a wide range of diseases, including avianflu.

"This is the race we have to win--to sufficiently mobilize theinterferon system early enough so that it will knock out the virusmultiplication," said Professor Luc Montagnier, President of theFoundation for AIDS Research and Prevention, who is widely creditedwith discovering the AIDS virus, HIV. "I believe that in addition tothe anti-viral effect, Alferon(R) LDO will mobilize another importantcomponent 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 healthyvolunteers, being conducted at the Princess Margaret Hospital in HongKong indicate that Alferon(R) LDO may strengthen human immuneresponses via interferon-activated genes, potentially staving offinfection should an individual be thereafter exposed to the virus. Bypriming the body's own interferon pump, Alferon(R) LDO might enable aninfected host to produce enough interferon to overcome the virus. Thestudies being reported today include specific markers of immuneresponse following exposure to Alferon(R) LDO in the absence of anyviral exposure.

"Given the potential for a pandemic, these results may havesignificant implications for control of the avian flu virus," saidWilliam A. Carter, M.D., Chairman and CEO of Hemispherx Biopharma. "Inrelevant animal models and human volunteer studies, both experimentalimmunotherapeutics, Ampligen(R) and Alferon(R) LDO may trigger theproduction of novel defense products as part of the body's immunesystem. Therefore, we are encouraged that these experimentalimmunotherapeutics represent a significant new path forward inpotential 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 thisyear. Since Alferon(R) N Injection is already FDA-approved, HemispherxBiopharma would file various amendments globally to its existingapproval licenses, reflecting a different method of delivery anddifferent efficacy data on any potentially new therapeuticapplications, including avian flu.

About Hemispherx Biopharma

Hemispherx Biopharma, based in Philadelphia, is abiopharmaceutical company engaged in the manufacture and clinicaldevelopment of new drug entities for treatment of viral andimmune-based chronic disorders. Hemispherx Biopharma's flagshipproducts include Alferon(R) and the experimentalimmunotherapeutics/antivirals Ampligen(R) and Oragens(TM). Alferon(R)is approved for a category of STD infection, and Ampligen(R) andOragens(TM) represent experimental nucleic acids being developed forglobally important viral diseases and disorders of the immune system.Hemispherx's platform technology includes large and small agentcomponents for potential treatment of various chronic viralinfections. Hemispherx has in excess of 140 patents comprising itscore intellectual property estate, a fully commercialized product(Alferon(R) N) and GMP certified manufacturing facilities for itsnovel pharma products. For more information please visitwww.hemispherx.net

www.hemispherx.net

Information contained in this news release other than historicalinformation, should be considered forward-looking and is subject tovarious risk factors and uncertainties. For instance, the strategiesand operations of Hemispherx involve risk of competition, changingmarket conditions, change in laws and regulations affecting theseindustries and numerous other factors discussed in this release and inthe Company's filings with the Securities and Exchange Commission. Anyspecifically referenced investigational drugs and associatedtechnologies of the company (including Ampligen(R), Alferon(R) LDO andOragens) are experimental in nature and as such are not designatedsafe and effective by a regulatory authority for general use and arelegally available only through clinical trials with the referenceddisorders. The forward-looking statements represent the Company'sjudgment as of the date of this release. The Company disclaims,however, any intent or obligation to update these forward-lookingstatements. Clinical trials for other potential indications of theapproved biologic Alferon(R) do not imply that the product will everbe specifically approved commercially for these other treatmentindications.