Hemispherx Biopharma: Institute of Medicine, the Health Arm of the US National Academy of Sciences Reframes Chronic Fatigue Syndrome (CFS) as a "Systemic Exertion Intolerance Disease" (SEID)

Philadelphia, PA, Monday, February 23, 2015: Hemispherx Biopharma, Inc. (NYSE MKT: HEB) (the "Company" or "Hemispherx"), announced today that a new report, issued February 10, 2015 by the Institute of Medicine (IOM) of the National Academy of Sciences, recommends that the disorder previously known as Chronic Fatigue Syndrome (CFS) be changed to Systemic Exertion Intolerance Disease (SEID) - in the Institute's words - "to more accurately capture the central characteristics of the disease". To Hemispherx's knowledge, it is the only pharmaceutical company which to date has used quantitatively measured exercise tolerance (via exercise treadmills operated by independent exercise physiologists) over time in an attempt to understand patient response when its experimental therapeutic, Ampligen®, is compared to placebo. The Institute's report is titled "Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Redefining an Illness".

According to the IOMs report brief of February 10, 2015, "The Department of Health and Human Services (HHS), the National Institutes of Health, the Agency for Healthcare Research and Quality, the Centers for Disease Control and Prevention, the Food and Drug Administration, and the Social Security Administration asked the Institute of Medicine (IOM) to convene an expert committee to examine the evidence base for ME/CFS. In Beyond Myalgic
Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness, the committee proposes new diagnostic criteria that will facilitate timely diagnosis and care and enhance understanding among health care providers and the public. In addition, the committee recommends that the name of the disease be changed - from ME/CFS to systemic exertion intolerance disease (SEID) - to more accurately capture the central characteristics of the illness.ME/CFS is a serious, chronic, complex, systemic disease that often can profoundly affect the lives of patients."

Further, the IOM, in its opening remarks, commented "Between 836,000 and 2.5 million Americans suffer from myalgic encephalomyelitis/chronic fatigue syndrome - commonly referred to as ME/CFS. This disease is characterized by profound fatigue, cognitive dysfunction, sleep abnormalities, autonomic manifestations, pain, and other symptoms that are made worse by exertion of any sort. ME/CFS can severely impair patients' ability to conduct their normal lives. Yet many people struggle with symptoms for years before receiving a diagnosis. Fewer than one-third of medical school curricula and less than half of medical textbooks include information about ME/CFS. Although many health care providers are aware of ME/CFS, they may misunderstand the disease or lack knowledge about how to diagnose and treat it. Such gaps in understanding lead to delayed diagnoses and inappropriate management of patients' symptoms." To read the full report, go to http://www.iom.edu/Reports/2015/ME-CFS.aspx.

The Institute's report states "Many health care providers are skeptical about the seriousness of ME/CFS, mistake it for a mental health condition, or consider it a figment of the patient's imagination. Misconceptions or dismissive attitudes on the part of health care providers make the path to diagnosis long and frustrating for many patients. The committee stresses that health care providers should acknowledge ME/CFS as a serious illness that requires timely diagnosis and appropriate care."

The report recommends that SEID be entered into the International Classification of Diseases (ICD-10) - the book that physicians around the world use to make diagnoses.

Medical commentary on the new diagnostic algorithm for ME/CFS are more fully discussed across a wide spectrum of scientific journals appearing at this time including Journal of the American Medical Association, Scientific American, the Annals of Internal Medicine, TheScientist magazine and various scientific sections of the NY Times and Washington Post. An overarching conclusion of both the IOM report and additional physicians' commentary in the above referenced publications is that CFS is a serious physical disorder and not a psychological illness. "The (IOM) panel acknowledged what people with chronic fatigue syndrome have long complained about: They struggle, sometimes for years, before finding a health-care provider who diagnoses a disorder that often devastates their lives. Sixty-seven percent to 77 percent reported in surveys that it took longer than a year to receive a diagnosis, and about 29 percent said it took longer than five years."

In the Company's Phase III study of Ampligen® entitled "A Double-Blind, Placebo-Controlled, Randomized, Clinical Trial of the TLR-3 Agonist Rintatolimod in Severe Cases of Chronic Fatigue Syndrome", special study conditions were devised to measure Exercise Tolerance (ET) testing quantitatively (Strayer, et al. PLoS ONE 2012;7(3):e31334). The following standardized protocol was used:

Exercise Tolerance (ET) Testing with Ampligen® vs. Placebo

"Patients underwent treadmill ET testing according to a standardized protocol (Table S4). Subjects rated their perceived exertion, generally considered to be a reliable indicator of fatigue
[20], using the Borg Scale and progressed through stages successively until they could no longer continue. The ET result was recorded as the total time on the treadmill. In order to reduce
variation in test results, each site used the same make and model of treadmill (Trackmaster TM 225, Full Vision, Inc., Newton, Kansas USA) and the same group of exercise physiologists
traveled to each site to administer the treadmill test throughout the study. Treadmills were calibrated on the day of each test for speed and inclination. Two treadmill exercise tests were performed during baseline. If the two baseline tests differed by more than ±10% of the maximum duration from their mean value, a third test was performed. When three baseline tests were performed, the two closest tests were used for data analysis of ET."

Exercise Tolerance Results

This "Phase III prospective, double-blind, randomized, placebo-controlled trial comparing twice weekly IV rintatolimod versus placebo was conducted in 234 subjects with long-standing, debilitating CFS/ME at 12 sites. The primary endpoint was the intra-patient change from baseline at Week 40 in exercise tolerance (ET). Subjects receiving rintatolimod for 40 weeks improved intra-patient placebo-adjusted ET 21.3% (p = 0.047) from baseline in an intention-to-treat analysis. Correction for subjects with reduced dosing compliance increased placebo adjusted ET improvement to 28% (p = 0.022). The improvement observed represents approximately twice the minimum considered medically significant by regulatory agencies. Placebo subjects crossed over to receive rintatolimod demonstrated an intra-patient improvement in ET performance at 24 weeks of 39% (p = 0.04)."

On December 20, 2012, an FDA Advisory Committee voted in favor of the safety of the product for commercial use (vote 8 to 5), but not in favor of its efficacy (4 to 9). Thereafter, FDA issued a Complete Response Letter with regard to the Ampligen NDA, requesting additional data to be generated before the NDA would be approved. Recently on January 12, 2015, the Company issued a report entitled "Low Natural Killer (NK) Activity Observed Across the Chronic Fatigue Syndrome (CFS) Disease Spectrum" that a biomarker natural killer cell cytotoxicity (NKCC), when low, was associated with more symptom severity and debilitation. This report has now been submitted as a scientific paper for peer-review and publication. The report includes a summary of 6 publications totaling over 150 CFS patients which indicates a relationship between increased severity of CFS and low NK cell activity. In 15 subjects with CFS studied by the Company, Ampligen® treatment of peripheral blood mononuclear cells in vitro increased the mean NK activity over 100%. Clinical testing is presently underway to determine whether or not NK augmentation by Ampligen®, to the extent it may occur in vivo, is associated with decreased CFS disease severity and, specifically, increased physical performance.

About Ampligen®
Ampligen®, an experimental therapeutic, is a new class of specifically-configured ribonucleic acid (RNA) compounds targeted as potential treatment of diseases with immunologic defects and/or viral causation.

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 especially life-threatening viruses. 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 including cancers. 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. and Argentina. The FDA approval of Alferon® N Injection® is limited to the treatment of refractory or recurrent external genital warts in patients 18 years of age or older. The Company's Alferon N Injection® approval in Argentina includes the use of Alferon N Injection® (under the brand name "Naturaferon") for use in any patients who fail, or become intolerant to recombinant interferon, including patients with chronic active hepatitis C infection. 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.




Disclosure Notice
The information in this press release includes certain "forward-looking" statements including without limitation statements about additional steps which the FDA may require and Hemispherx may take in continuing to seek commercial approval of the Ampligen® NDA for the treatment of Chronic Fatigue Syndrome in the United States and abroad. 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 in the United States and other countries. Any failure to satisfy the FDA regulatory requirements or the requirements of other countries could significantly delay, or preclude outright, approval of Ampligen® in the United States and other countries.

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, changes 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. No evidence has suggested that Ampligen® will ever be commercially approved for the new potential treatment indications, including, but not limited, to the treatment of CFS.

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 "intends," "plans," and similar expressions are intended to identify forward-looking statements. 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. No evidence is suggested that Ampligen® will ever be commercially approved for the CFS treatment indications mentioned in this release.



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