Hemispherx Biopharma and the FDA Reach Agreement on Filing Requirements for the Company's Complete Response in Support of Ampligen® New Drug Application for Chronic Fatigue Syndrome Treatment

PHILADELPHIA, July 11, 2012 (GLOBE NEWSWIRE) -- Hemispherx Biopharma, Inc. (NYSE:HEB) (the "Company" or "Hemispherx") recently met with representatives of the U.S. Food and Drug Administration (the "FDA"). At that meeting, the FDA agreed to accept, for review, new analyses of data from Hemispherx's AMP-516 Phase III Clinical Trial ("AMP-516 Trial") in support of its New Drug Application ("NDA") for Ampligen^® (Poly I : Poly C12U). If found sufficient to support approval of the drug, these new analyses will be in lieu of an additional confirmatory Phase III study called for in the Agency's November 25, 2009, Complete Response Letter ("CRL"). The FDA has advised that whether the new analyses provide adequate evidence of Ampligen^®'s efficacy in treating Chronic Fatigue Syndrome ("CFS") will ultimately be a review issue.

In its CRL, the FDA recommended at least one additional clinical study of Ampligen^® in CFS patients, including at least 300 patients on dose regimens intended for marketing. In November 2010, Hemispherx announced the publication of new analyses of data from the AMP-516 Trial showing that patients on Ampligen^® reduced their use of concomitant medications compared to patients receiving placebo. In particular, Ampligen^® patients reduced their use of medications which may prolong the QT interval. Prolongation of the QT interval is a known risk factor for sudden cardiac death and arrhythmias. A greater portion of the placebo patients were found to have a significant prolongation of the QT interval compared to patients who had received Ampligen^®, thereby creating a cardiac risk situation in the CFS patients. Cardiac death is one of three major causes of premature death in CFS, which affects predominantly women in their 40s. The article can be found at http://jrnlappliedresearch.com/articles/Vol10Iss3/Vol10%20Iss3Stouch.pdf. At present, no drug has received FDA approval to treat this chronic, seriously debilitating disease.

In March, 2012, a new peer reviewed analysis of data from the AMP-516 Trial was published showing that the proportions of Ampligen^® patients with exercise improvements of at least 25% and at least 50% were, respectively, 1.7 and 1.9-fold greater than those patients on placebo. A continuous responder analysis, which examined response improvements from 25% to 50% in 5% increments, showed a greater improvement in exercise tolerance for patients receiving Ampligen^® versus placebo at every 5% increment above 25%. The article can be found at http://dx.plos.org/10.1371/journal.pone.0031334.

On June 8, 2012, the Company and its consultants met with the FDA to discuss certain aspects of the CRL relating to its NDA for Ampligen^® for the treatment of severely debilitated patients with CFS. At this time, the Company believes the key points from the meeting to be undertaken by the Company in conjunction with its complete response include the following:

• The FDA agreed to accept, for review, in Hemispherx’s complete response new analyses of data from the AMP-516 Trial. Whether these data provide adequate evidence of efficacy will ultimately be a review issue, and there can be no assurance the FDA will conclude the data are adequate to support approval of the Ampligen^® NDA.

• As the product is a new molecular entity, the FDA anticipates that the data submitted in the NDA would be presented at a public FDA Advisory Committee meeting.

• The FDA requires that the Company’s complete response include all information necessary for review at the time of filing and that it address all deficiencies identified in the CRL.

• Hemispherx's New Brunswick manufacturing facility would be expected to be ready for GMP pre-approval inspection at the time of the complete response.

• Hemispherx will include in the complete response a request for postponement of rodent carcinogenicity study requirements and a justification for this request.

Hemispherx plans to submit the complete response in the 3rd quarter 2012. The FDA has advised that, once submitted, the complete response will be on a six month review cycle at the FDA. The FDA's agreement to review the complete response does not commit the Agency to approve the Ampligen^® NDA. Further, although the proposed New Brunswick manufacturing facility already has received a Biologics License from the FDA for its commercial product, Alferon N Injection^®, no guarantee can be made at this time that the facility will necessarily pass a pre-approval inspection for Ampligen^® manufacture, which is conducted in a separately dedicated area within the overall New Brunswick manufacturing complex.

As a result of the meeting, Hemispherx has accelerated its preparedness for FDA pre-approval inspections by hiring additional staff, consultants, and various independent contractors.