SOURCE: DOR BioPharma, Inc.

December 07, 2006 09:25 ET

DOR BioPharma Announces Notice of Allowance for Key Ricin Toxin Vaccine Patent

MIAMI, FL -- (MARKET WIRE) -- December 7, 2006 -- DOR BioPharma, Inc. (OTCBB: DORB) ("DOR" or the "Company") announced today that the United States Patent and Trademark Office (USPTO) has issued a Notice of Allowance of patent claims based on U.S. Patent Application #09/698,551 titled "Ricin A chain mutants lacking enzymatic activity as vaccines to protect against aerosolized ricin." This patent includes methods of use and composition claims for RiVax™, DOR's vaccine against ricin toxin and the lead product in its BioDefense portfolio.

RiVax™ is a vaccine that contains a recombinant subunit of the A chain of ricin toxin which induces ricin neutralizing antibodies in humans and animals. The University of Texas Southwestern Medical Center at Dallas (UTSW) is the owner of the patent and DOR has licensed exclusive, worldwide rights for the production, sales and marketing of RiVax™. The development of RiVax™ is derived directly from the claims that have been allowed in the new patent application.

"This Notice of Allowance represents a major milestone in obtaining broad patent coverage for the underlying technology and is one of the critical steps in our commercialization strategy for RiVax™," said Christopher J. Schaber, President and CEO of DOR. "We continue to be excited about developing a ricin vaccine to protect against the potential use of ricin toxin as a biological weapon. The technology that Dr. Vitetta and her colleagues at UTSW have developed for RiVax™ is considered the strongest in this area. We expect that the introduction of a safe and effective ricin vaccine will be a step forward in the national effort to develop effective countermeasures and therapies for significant biothreats and emerging pathogens."

About the New Patent

This new patent will significantly extend the Company's patent protection for RiVax™. Following receipt of the Notice of Allowance, the Company expects that a patent will issue in early 2007. With 49 claims, the allowed patent covers the technology that describes the derivation of the ricin A chain antigen, which constitutes the immunogenic component of RiVax™.

Ricin is a highly potent plant toxin that is comprised of two molecular chains: the B chain, which causes it to bind to cells with high affinity; and the A chain, which contains several sites that inactivate cellular machinery and induce its characteristic toxicity. One of the sites in the A chain has enzymatic activity and cleaves specific residues in RNA that inactivates protein synthesis.

The allowed claims in the patent application include the combination of specific mutations in the enzymatically active site of ricin A chain with specific mutations in the site that induces Vascular Leak Syndrome (VLS). VLS is thought to result from the binding of ricin A chain to endothelial cells causing fluid leakage and to lead to local tissue damage after exposure to a molecule that has an intact VLS site. The combination of mutations in each of the key sites for ricin toxicity ensures that the recombinant subunit is inherently safe. Studies conducted by Dr. Ellen Vitetta, Director of the Cancer Immunobiology Center at UTSW, and her colleagues have indicated that the specific mutations introduced into the ricin A chain eliminate the toxic activity of the molecule, but do not alter the structure, permitting a highly immunogenic and safe vaccine.

The allowed patent is the second patent related to the technology basis for the construction of RiVax™ to be issued in the United States. The first patent in this family, U.S. patent #6,566,500, "Compositions and methods for modifying toxic effects of proteinaceous compounds," describes specific mutations which result in the loss of one of the toxic activities of the A chain of ricin that leads to VLS.

About RiVax™

RiVax™ has been shown to be safely tolerated in humans in a Phase I dose-escalating trial conducted last year. Doses as high as 100 micrograms of the modified subunit given three times intramuscularly did not result in any side effects associated with the activity of natural ricin toxin. Even without an adjuvant, RiVax™ induced antibodies in all five of the individuals who received the highest dose, four out of five who received the intermediate dose, and one out of five who received the lowest dose levels. The functional activity of the antibodies was confirmed by transferring serum globulins from the vaccinated individuals along with active ricin toxin to mice that subsequently survived exposure to ricin.

DOR has been leading a consortium of academic and industry vaccine investigators under funding from National Institute of Allergy and Infectious Diseases (NIAID) in the development of RiVax™. The consortium effort began in 2004 with a $6.4 million grant award covering process development and GMP scale manufacturing for RiVax™. Recent grant funding of approximately $5.0 million has broadened the development capabilities of the program in further animal testing and formulation.

About Ricin Toxin

Ricin toxin is a potential bioterror threat due to its high toxicity in small doses, ease of production and ability to be aerosolized, and has been categorized as a category B biothreat by the Center for Disease Control (CDC) and the National Institutes of Health (NIH). Exposure to small amounts can lead to lung damage if inhaled, and 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 has been emphasized by its recent and continued use as a biological weapon. Currently, there is no FDA approved vaccine or countermeasure against ricin toxin.

About DOR BioPharma, Inc.

DOR BioPharma, Inc. 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 with the FDA for the treatment of GI GVHD, and has received an FDA PDUFA date of July 21, 2007. An MAA with the EMEA for orBec® has also been filed and validated. orBec® may also have application in treating other gastrointestinal disorders characterized by severe inflammation.

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. The ricin toxin vaccine, RiVax™, has been evaluated successfully in a Phase 1 clinical trial in normal volunteers.

For further information regarding DOR BioPharma, please visit the Company's website located at

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 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.

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