Hemispherx Biopharma Announces Purchase of Royalty Interest from Stem Cell Innovations, Inc.; Only Natural Alpha Interferon Product on the U.S. Market.

PHILADELPHIA -- Hemispherx Biopharma, Inc. (AMEX: HEB) announced today it has purchased the royalty interest related to the sales of its natural alpha interferon products from Stem Cell Innovations, Inc. (previously known as Interferon Sciences, Inc.). In March 2004 Hemispherx acquired the 43,000 square foot research and FDA approved manufacturing facility in New Brunswick, N.J. and the worldwide license for the production, manufacture, use, marketing and sale of Alferon N Injection(R). The royalty interest on the interferon products was a residual of this transaction.

Hemispherx Biopharma's Alferon N Injection(R) is the first and only natural human alfa interferon product made available in the United States. It is an FDA approved treatment for human papilloma viruses (HPV) and clinical trials are planned to extend the treatment indication to other HPV related disorders, especially in the female health sector.

Early studies with partially purified, natural alpha interferons in low doses demonstrated efficacy in preventing and treating human influenza outbreaks. These studies, conducted by others in Asia and the Soviet Union, were curtailed due to insufficient assurances of pure blood supplies containing the leukocytes necessary for the manufacture of natural alpha interferons. The Hemispherx process has utilized leukocytes derived from blood supplies from the American Red Cross. With blood purity assured and with the enhanced efficacy indicated from continued clinical research and a refined manufacturing process, Hemispherx has expanded upon the earlier pioneering research and is now pursuing a promising oral derivative of Alferon N Injection(R) called Alferon Low Dose Oral (LDO).

Alferon LDO is derived from Alferon N Injection(R) and features a new, recently patented, experimental oral delivery method that could make mass distribution achievable and efficient and has the potential to reduce the incidence and mortality of pandemic influenza.

Dr. William A. Carter, chairman & CEO of Hemispherx Biopharma, Inc., stated that "the elimination of the royalty obligation was an important milestone in the pursuit of our ultimate objective of strong profitability."

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 disorders, including gene-based disdorders such as Chronic Fatigue Syndrom (CFS). Hemispherx Biopharma's flagship products include Alferon N Injection(R) and the experimental therapeutics/antivirals Ampligen(R) and Oragens(TM). Alferon N Injection(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 viral infections. 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 within the United States. 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(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 N Injection(R) or the experimental therapeutic Ampligen(R) do not imply that the product will ever be specifically approved commercially for these other treatment indications.