FDA Accepts Complete Response Submission Regarding

FDA Accepts Complete Response Submission Regarding the Ampligen(R) New Drug Application for Chronic Fatigue Syndrome

Hemispherx Biopharma, Inc. (NYSE:HEB) (the "Company" or "Hemispherx") filed on July 31, 2012 with the U.S. Food and Drug Administration its complete response to the FDA's November 25, 2009 Complete Response Letter in support of Ampligen^®'s New Drug Application for Chronic Fatigue Syndrome ("CFS"). (Please see the Company's press release and Form 8-K dated August 1, 2012.) On August 10, 2012, the FDA acknowledged in writing receipt of the Company's August 1, 2012, response stating, "We consider this a complete, class 2 response to our November 25, 2009, action letter. Therefore, the user fee goal date is February 2, 2013."

Thomas Equels, Vice Chairman of Hemispherx, stated, "We welcome this recent FDA confirmation and acceptance of our resubmission. At present, no drug has received FDA approval to treat CFS, a chronic, seriously debilitating disease suffered by millions of Americans. While the FDA's acceptance of our resubmission does not commit the Agency to approve the Ampligen^® NDA, the Company is pleased to have the opportunity for FDA review and consideration. Because the user fee goal date is February 2, 2013, we hope to receive a decision by the FDA on or before that date."

DISCLOSURE NOTICE: The information in this press release includes certain "forward-looking" statements (explained below), including statements about the remaining steps to potentially gain FDA approval of the Ampligen^® NDA for the treatment of Chronic Fatigue Syndrome. The final results of these and other ongoing activities could vary materially from Hemispherx's expectations and could adversely affect the chances for approval of the Ampligen^® NDA. These activities and the ultimate outcomes are subject to a variety of risks and uncertainties, including but not limited to risks that (i) the FDA may ask for additional data, information or studies to be completed or provided prior to approval; and (ii) the FDA may require additional work related to the commercial manufacturing process to be completed prior to approval or may, in the course of the inspection of manufacturing facilities, identify issues to be resolved. Any failure to satisfy the FDA's requirements could significantly delay, or preclude outright, approval of the Ampligen^® NDA.