Philadelphia, PA, Monday, March 04, 2013: Hemispherx Biopharma, Inc. (NYSE MKT: HEB) (the "Company" or "Hemispherx"), announced that ANMAT (Administracion Nacional de Medicamentos, Alimentos y Tecnologia Medica), the agency responsible for the national regulation of drugs, foods and medical technology in Argentina, has approved the use of Alferon N Injection® (under the brand name "Naturaferon") in Argentina for any patient that fails or becomes intolerant to treatment with recombinant interferon. Alferon N Injection® is an FDA-approved natural interferon and, as Naturaferon, is already approved in Argentina for the treatment of refractory or recurring external condylomata acuminata (genital warts).

Jorge Braver, President of GP Pharm SA and Hemispherx's partner in Argentina, said "We are very pleased that the ANMAT approved the expansion of the labeling for Naturaferon. Now patients in Argentina with hepatitis C, multiple sclerosis, certain cancers and other diseases who should not be treated with recombinant interferon, including pegylated alpha interferons, will have access to our therapy. In many cases, these patients would have had no alternative." GP Pharm believes this approval will also result in expanded insurance coverage for patients who receive Naturaferon for these additional indications.
Thomas Equels, Executive Vice Chairman of Hemispherx, stated, "Hepatitis C affects over 800,000 people in Argentina and while the prevalence of multiple sclerosis there is much lower it can be severely debilitating, particularly in patients with a high rate of relapse. We view this progress in Argentina as continued demonstration of our efforts to expand the market for Alferon N Injection® both geographically and by indication." Both the use of the Company's existing inventory of Alferon N Injection® for sale in Argentina as well as the use of drug to be manufactured in the future when the Company's Alferon® manufacturing facility in New Brunswick is completed will require FDA approval. Therefore the timelines for when drug can be shipped to Argentina and when resulting revenues in Argentina will occur cannot be determined at this time.

Patients on recombinant interferon can become intolerant to treatment with the side effects outweighing the benefits of the therapy. In addition, patients can become refractory to such treatment because they develop antibodies to recombinant interferon which can dramatically reduce its effectiveness. In a peer-reviewed article published in the Journal of Interferon and Cytokine Research (Volume 32, pages 95-102; http://online.liebertpub.com/doi/abs/10.1089/jir.2011.0069?journalCode=jir), Hemispherx provided an analysis of the incidence and clinical impact of neutralizing antibodies ("NABs") formed during treatment with recombinant interferons compared to natural interferons, such as Alferon N Injection®, across a wide range of human diseases. The fraction of relapsed and refractory patients was reported as statistically greater in NAB positive patients compared to NAB negative patients (p < 0.0001),="" whereas="" the="" percentage="" of="" responding="" patients="" was="" reported="" as="" higher="" in="" nab="" negative="" patients="" (p="">< 0.001).="" another="" analysis="" looked="" at="" relapsed="" and="" refractory="" nab="" positive="" patients="" who="" were="" then="" switched="" to="" natural="" interferon.="" across="" all="" the="" different="" diseases="" the="" authors="" reviewed,="" 33="" out="" of="" 40="" or="" 82%="" of="" these="" patients="" had="" their="" clinical="" response="" restored="" after="" switching="" to="" natural="">

DISCLOSURE NOTICE: The information in this press release includes certain "forward-looking" statements (explained below), including statements about the likelihood of the use of Naturaferon (Alferon N Injection®) for the treatment of various diseases in Argentina and the timelines for when drug can be shipped to Argentina and when revenues will occur. 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. The final results of these efforts could vary materially from Hemispherx's expectations.

About Hemispherx Biopharma
Hemispherx Biopharma, Inc. is an advanced specialty pharmaceutical 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® and the experimental therapeutics Ampligen® and Alferon® LDO. Ampligen® is an experimental RNA nucleic acid being developed for globally important debilitating diseases and disorders of the immune system, including Chronic Fatigue Syndrome. Hemispherx's platform technology includes components for potential treatment of various severely debilitating and life threatening diseases. Because both Ampligen® and Alferon® LDO are experimental in nature, they are not designated safe and effective by a regulatory authority for general use and are legally available only through clinical trials. Hemispherx has patents comprising its core intellectual property estate and a fully commercialized product (Alferon N Injection®), approved for sale in the U.S. for refractory or recurring external genital warts in patients 18 years of age or older. The Company wholly owns and exclusively operates a GMP certified manufacturing facility in the United States for commercial products. For more information please visit www.hemispherx.net.

About GP Pharm
GP Pharm SA headquarters are located in Barcelona, Spain with operations in each major country in Latin America either directly or through local partners. Its activities are focused on research, development and marketing of injectable products made by others and by GP Pharm based on its proprietary drug delivery systems including microspheres and liposomes. GP Pharm's new production plant recently achieved EU GMP approval and started manufacturing operations, producing the first batches of own products and also for some contract manufacturing partners. Its facilities are also designed to be FDA GMP compliant. GP Pharm has a centralized free-zone distribution facility in Uruguay for its own products as well as its partners' products.



Forward-Looking Statements
To the extent that statements in this press release are not strictly historical, all such statements are forward-looking, and are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Words such as "hopes," "believes," "plans," "anticipates," and similar expressions are intended to identify forward-looking statements. These statements are based on the Company's or GP Pharm's current beliefs and expectations and represent the Company's or GP Pharm's judgment as of the date of this release. The inclusion of forward-looking statements should not be regarded as a representation by Hemispherx that any of its plans will be achieved. These forward-looking statements are neither promises nor guarantees of future performance, and are subject to a variety of risks and uncertainties, many of which are beyond Hemispherx's control, which could cause actual results to differ materially from those contemplated in these forward-looking statements. Examples of such risks and uncertainties include those set forth in the Disclosure Notice, above, as well as the risks described in Hemispherx's filings with the Securities and Exchange Commission, including the most recent reports on Forms 10-K, 10-Q and 8-K. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof, and Hemispherx undertakes no obligation to update or revise the information contained in this press release, whether as a result of new information, future events or circumstances or otherwise revise or update this release to reflect events or circumstances after the date hereof.



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