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DOR BioPharma Announces Publication Describing Protection Against Oral and Aerosol Ricin Exposure With Its Ricin Vaccine RiVax

Ricin Toxin Found to Be 2000 Fold More Lethal by Oral Route Than Previously Described

MIAMI, FL--(Marketwire - September 05, 2007) - DOR BioPharma, Inc. (OTCBB) ("DOR" or the "Company") announced today results from animal testing of RiVax™, its vaccine against ricin toxin, have been published online in the journal Vaccine, Smallshaw et al., "RiVax™, A Recombinant Ricin Subunit Vaccine, Protects Mice Against Ricin Given by Gavage or Aerosol" (web link to article: http://dx.doi.org/doi:10.1016/j.vaccine.2007.08.018). The publication describes the findings that RiVax™ can induce protection against mortality and tissue damage from both aerosol and oral toxin exposure; the most likely routes to be used in a ricin toxin biological attack. The publication was authored by investigators at the University of Texas Southwestern Medical Center at Dallas (UT Southwestern), one of the Company's academic partners in the development of RiVax™.

RiVax™ is already known to induce antibodies that appear primarily in the blood of animals and humans. Such antibodies in the blood are correlated to protection against exposure when the toxin reaches the circulation. One of the major effects of ricin toxin exposure through the lungs is rapid and massive lung injury that leads to death. It was not known how well RiVax™ would protect when ricin toxin was inhaled or ingested. This recent study demonstrated that RiVax™ not only protects mice against the lethal effects of the aerosolized toxin, but it can also prevent damage to lung tissue. RiVax™ protected animals against lung injury as measured by lung function tests and histological lesions induced by the toxin in a dose-dependent manner, where the amount of antibodies circulating in the blood correlated directly to protection against lung injury. It was also confirmed that RiVax™ protected mice against lethal effects when they were fed the ricin toxin. These results indicate that it is possible to induce antibodies primarily in circulation that are correlated with protection when the toxin contacts lung and gastrointestinal tissue.

"It is now clear that RiVax™ induces excellent protection against oral and aerosol ricin toxin exposure, and protects mucosal tissue against the direct effects of the toxin," said Ellen Vitetta, PhD, Director of the Cancer Immunobiology Center at UT Southwestern and the study's corresponding author. "The current results also show that pure ricin toxin is 2000 fold more toxic by the oral route than previously described, which is very surprising, since the literature has described much larger doses to cause mortality when ricin is fed to animals."

"We have always believed the potential for a biological attack with aerosolized ricin toxin to be significant given its ease of production; therefore, it was critical to demonstrate that RiVax™ protected against aerosol exposure," said Robert N. Brey, PhD, DOR's Chief Scientific Officer. "The next step will be to evaluate RiVax™ as protection against aerosol exposure in a higher animal species. The correlation of antibodies with protection against aerosol exposure will be a critical component necessary to support the use of RiVax™ in humans as a licensed vaccine or under emergency use authorization. We think that these results provide strong evidence that an injected form of RiVax™ will prove sufficient to induce antibodies to protect mucosal tissues in the lung as well as the gastrointestinal tract."

The Company has been developing RiVax™ in a consortium effort between academic and industrial partners under several separate NIAID and FDA grants to DOR and UT Southwestern totaling approximately $15 Million. In addition to UT Southwestern, development partners include, Stanford Research Institute (SRI International), the University of Kansas, Lonza Baltimore, and the Wadsworth Center of the New York State Department of Health in Albany.

The development program, through UT Southwestern, has also been recently awarded a $1 million FDA Orphan Products grant to carry out additional clinical testing of RiVax™. Dr. Ellen Vitetta has also separately been awarded a grant for $2.2 million over 5 years to conduct research in fundamental areas to develop novel vaccine formulations and characterize immune responses in small animals. The outcome of that novel research will help support ongoing development of RiVax™.

RiVax™ is a recombinant subunit of the ricin toxin A chain and has been genetically detoxified. The subunit is produced in recombinant bacterial hosts, purified, and formulated for human and animal testing.

About Ricin Toxin

Ricin toxin is a potent plant toxin that can be easily produced from abundantly available castor beans. There exists no vaccine to protect against exposure nor post-exposure therapeutic other than supportive care. Ricin toxin is highly toxic to humans and other mammals and is a thought to be a bioterror threat because of its environmental stability and high potency, second only to botulinum toxin as a natural toxin. Exposure to small amounts can lead to lung damage if inhaled with rapid onset of nausea, fever, and abdominal pain if ingested. General organ failure leading to death can occur within several days. The need for protective countermeasures against ricin toxin has been emphasized by its recent and continued use as a biological weapon. The successful development of an effective vaccine against ricin toxin may act as a deterrent in the actual use of ricin as a biological weapon and could be used in rapid deployment scenarios in the event of a biological attack.

About DOR BioPharma, Inc.

DOR BioPharma, Inc. (DOR) is a biopharmaceutical company developing products to treat life-threatening side effects of cancer treatments and serious gastrointestinal diseases, and vaccines for certain bioterrorism agents. DOR's lead product, orBec® (oral beclomethasone dipropionate), is a potent, locally acting corticosteroid being developed for the treatment of GI GVHD, a common and potentially life-threatening complication of bone marrow transplantation. DOR has filed an NDA for orBec® with the FDA for the treatment of GI GVHD, and subsequent to supplemental information recently submitted, the FDA has extended the PDUFA (Prescription Drug User Fee Act) date to October 21, 2007. An MAA (Marketing Authorization Application) with the EMEA (European Medicines Evaluation Agency) has also been filed and validated. orBec® may also have application in treating other gastrointestinal disorders characterized by severe inflammation. DOR has also recently initiated a development program with its Lipid Polymer Micelle (LPM™) oral drug delivery technology for the oral delivery of leuprolide for the treatment of prostate cancer and endometriosis.

Through its Biodefense Division, DOR is developing biomedical countermeasures pursuant to the recently enacted Project BioShield Act of 2004. DOR's biodefense products in development are recombinant subunit vaccines designed to protect against the lethal effects of exposure to ricin toxin and botulinum toxin. DOR's ricin toxin vaccine, RiVax™, has been shown to be safely tolerated and immunogenic in a Phase 1 clinical trial in normal volunteers.

For further information regarding DOR BioPharma, please visit the Company's website located at http://www.dorbiopharma.com.

This press release contains forward-looking statements, within the meaning of Section 21E of the Securities Exchange Act of 1934, that reflect DOR BioPharma, Inc.'s current expectations about its future results, performance, prospects and opportunities, including statements regarding the potential use of orBec® for the treatment of gastrointestinal GVHD and the prospects for regulatory filings for orBec®. Where possible, DOR has tried to identify these forward-looking statements by using words such as "anticipates," "believes," "intends," or similar expressions. These statements are subject to a number of risks, uncertainties and other factors that could cause actual events or results in future periods to differ materially from what is expressed in, or implied by, these statements. DOR cannot assure you that it will be able to successfully develop or commercialize products based on its technology, including orBec®, particularly in light of the significant uncertainty inherent in developing vaccines against bioterror threats, manufacturing and conducting preclinical and clinical trials of vaccines, and obtaining regulatory approvals, that its technologies will prove to be safe and effective, that its cash expenditures will not exceed projected levels, that it will be able to obtain future financing or funds when needed, that product development and commercialization efforts will not be reduced or discontinued due to difficulties or delays in clinical trials or due to lack of progress or positive results from research and development efforts, that it will be able to successfully obtain any further grants and awards, maintain its existing grants which are subject to performance, enter into any biodefense procurement contracts with the U.S. Government or other countries, that the U.S. Congress may not pass any legislation that would provide additional funding for the Project BioShield program, that it will be able to patent, register or protect its technology from challenge and products from competition or maintain or expand its license agreements with its current licensors, or that its business strategy will be successful. Important factors which may affect the future use of orBec® for gastrointestinal GVHD include the risks that: because orBec® did not achieve statistical significance in its primary endpoint in the pivotal Phase 3 clinical study (i.e. a p-value of less than or equal to 0.05), the Oncologic Drug Advisory Committee ("ODAC") appointed by the FDA voted that the data supporting orBec® did not show substantial evidence of efficacy by a margin of 7 to 2 for the treatment of GI GVHD, although the FDA is not bound by ODAC's decision, the FDA may not consider orBec® approvable based upon existing studies, orBec® may not show therapeutic effect or an acceptable safety profile in future clinical trials, if required, or could take a significantly longer time to gain regulatory approval than DOR expects or may never gain approval; DOR is dependent on the expertise, effort, priorities and contractual obligations of third parties in the clinical trials, manufacturing, marketing, sales and distribution of its products; or orBec® may not gain market acceptance; and others may develop technologies or products superior to orBec®. These and other factors are described from time to time in filings with the Securities and Exchange Commission, including, but not limited to, DOR's most recent reports on Form 10-QSB and Form 10-KSB. DOR assumes no obligation to update or revise any forward-looking statements as a result of new information, future events, and changes in circumstances or for any other reason.

 

Company Contact:
Evan Myrianthopoulos
Chief Financial Officer
(786) 425-3848
http://www.dorbiopharma.com

 
 

Posted: September 2007

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