Hemispherx Biopharma Initiates Alferon LDO Clinical Program in Collaboration with Princess Margaret Hospital in Hong Kong.

PHILADELPHIA -- Experimental Effort to Prevent Sudden Spread of Dreaded Viruses in Large, At Risk Populations

Hemispherx Biopharma, Inc. (AMEX: HEB) announced today that the institutional review board of Hong Kong has approved a protocol for a randomized, dose-ranging study of Alferon(R) LDO (Low Dose Oral Interferon Alfa-n3 (Human Leukocyte Derived)) in normal volunteers and/or asymtomatic subjects with exposure to a person known to have SARS or possible SARS. This clinical study has been approved by the Clinical Research Ethics Committee of the Kowloon West Cluster at the Princess Margaret Hospital in Hong Kong.

Background

SARS (Severe Acute Respiratory Syndrome) is one of a group of "emerging" infectious disease that recently attracted the intense scrutiny of public health officials due to the severity of disease in epidemics based in Asia, but also involving Europe and North America as well. An international effort to limits its spread and to identify the infectious agent has been spectacularly successful and of major significance in the prevention of a pandemic. A replicating virus of classic coronavirus morphology was identified initially by electron microscopy. This identification of the virus family allowed the rapid identification of a new human coronavirus (SARS-CoV) as the etiological agent of SARS. Recently it has been observed that the US FDA approved antiviral drug, Alferon(R) (i.e.- natural interferon) has significant activity against SARS-CoV in vitro as indicated by reduction in cytopathic effect (CPE)(1). This protocol is designed to respond to the anticipated reemergence of SARS with a prophylaxis trial at epidemic sites to be conducted to evaluate the activity of Alferon LDO (low dose oral) to prevent symptomatic infection by SARS-CoV. Gene microarray analysis of infection by SARS-CoV and the effect of Alferon LDO are used in the design and conduct of this clinical trial. Differential cellular gene responses to infection and the response to Alferon may predict clinical outcomes.

The trial methodology may have implications for treating other emerging viruses such as avian influenza (bird flu). Present production methods for vaccines involve the use of millions of chicken eggs and would be slow to respond to an outbreak according to a recently convened World Health Organization (WHO) expert panel in November 2004. Health officials are also concerned that bird flu could mutate to cause the next pandemic and render present vaccines under development ineffective. The company has prepared more than 300,000 doses of Alferon LDO for appropriate clinical programs.

Objective

The objective of the study is to conduct a randomized dose-ranging study to evaluate the safety and activity of orally administered low dose alfa-n3 as an antiviral and immunomodulator in asymptomatic subjects with recent exposure to a person with SARS or possible SARS. The primary objective of this pilot study is to determine an Alferon LDO dose level that increases or upregulates genes known to be mediators of interferon response. In the event that no subjects with recent exposure to a person with SARS or possible SARS are available, this study will be conducted with 10 normal volunteers to study broad spectrum antiviral gene activation.

Study Design

This study will be an open-label, randomized, outpatient study in subject potentially infected with the SARS-CoV or normal volunteers using two dose levels of LDO interferon. Subjects will be randomized to receive Alferon(R) LDO (natural interferon anfa-n3) in a buffer solution once each day for 10 consecutive days at doses equal to 650 IU or 1300 IU/day. Pretherapy baseline evaluations will be performed prior to randomization.

Subjects will be randomly assigned to each dose level, and both dosage levels will be started concurrently. Drug will be dispensed for a ten day treatment period, during which time any clinical symptoms and adverse events will be evaluated. Laboratory samples (2.5 ml blood) for microarray analysis evaluations will be made twice during baseline and 12-14 hours following doses 1, 5, and 10 on study days 2, 6, and 11, respectively.

About Alferon LDO and Potential Public Health Enhancement in Developing Nations

Oral interferon is an experimental immunotherapeutic believed to work by stimulating an immune cascade response in the cells of the mouth and throat, enabling it to bolster an immune response through the entire body orally. Oral interferon would be much more economically feasible for patients and logistically manageable in development programs in third-world countries primarily affected by this and other emerging viruses (SARS, Ebola, bird flu, etc.). Oral administration of Alferon N(R), with its affordability, low toxicity, no production of antibodies, and broad range of potential bio activity, could be a breakthrough treatment for viral diseases.

About Hemispherx

Hemispherx Biopharma, based in Philadelphia, is a biopharmaceutical company engaged in the manufacture and clinical development of new drug entities. Its flagship products include Alferon N(R) and the experimental antivirals products, Ampligen(R) and Oragens(TM). These novel Alferon-N proteins, commercially available for a category of STD infection, and experimental nucleic acids are being developed for globally important chronic diseases and disorders of the immune system including HPV, HIV, CFS and Hepatitis. Its four major technology platforms include large-and small-agent components for potential treatment of various chronic viral infections, and are being developed with various corporate, governmental and academic collaborators worldwide. Hemispherx has approximately 400 patents comprising its core intellectual property estate, a fully commercialized product (Alferon N(R)) 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.