SOURCE: DOR BioPharma, Inc.

April 29, 2008 07:00 ET

DOR BioPharma Initiates Non-Human Primate Efficacy Studies of RiVax™, Its Vaccine Against Ricin Toxin

EWING, NJ--(Marketwire - April 29, 2008) - DOR BioPharma, Inc. (OTCBB: DORB) ("DOR" or "The Company"), a late-stage biopharmaceutical company, announced today the initiation of a comprehensive program to evaluate the efficacy of RiVax™ in non-human primates. RiVax™ is a recombinant subunit vaccine intended to protect humans against exposure to ricin toxin. The program, funded in large part by the National Institute of Allergy and Infectious Diseases (NIAID), is intended to supply efficacy data for RiVax™ in vaccinated rhesus monkeys (macaques) and to develop correlates of immunity. These data will further aid in interpretation of immunogenicity data obtained in human vaccination trials. The studies will take place at Tulane National Primate Research Center, a part of the Tulane University Health Sciences Center.

While prior Phase 1 clinical trial results for RiVax™ demonstrated that the vaccine is well tolerated and induces antibodies in humans that neutralize ricin toxin in tissue culture, it will be critical to obtain data proving that this response is protective. In the studies to be done at Tulane, it will be important to establish that vaccinated non-human primates are not only protected against lethality from ricin aerosol exposure, but also against lung damage. Rhesus macaques develop symptoms of ricin poisoning after aerosol exposure that are thought to be close to those symptoms that would ensue after human exposure. The study will be performed using Centers for Disease Control/US Department of Agriculture-approved biocontainment laboratories located at the Primate Center.

It has been previously demonstrated that mice develop protective immunity to aerosol and gastric ricin exposure after intramuscular vaccination with RiVax™, with little evidence of damage to lung tissue or intestinal tissue. The formulation of RiVax™ to be evaluated in rhesus macaques is an adjuvant-containing formulation that is expected to result in longer lasting and higher titer neutralizing antibodies and is also the vaccine to be tested in an upcoming Phase 2 human clinical trial. Since there are no existing data on human aerosol exposure, testing RiVax™ prospectively in animal models is needed to validate the use of the vaccine in emergency situations and before market approval by the US Food and Drug Administration (FDA).

"We are excited about the opportunity to test RiVax™ using Tulane's sophisticated telemetry system to monitor vaccinated macaques for possible lung damage from the aerosolized ricin toxin," said Robert N. Brey, Ph.D., Chief Scientific Officer of DOR. "We will have the opportunity to monitor the generation of antibodies in serum and mucosal fluids after vaccination with RiVax™. The rhesus macaque model offers the best opportunity to study the effects of vaccination and the overall effect of aerosolized ricin on health and will further guide us in determination of protective levels of antibodies from human trials."

About Ricin Toxin

The potential use of ricin toxin as a biological weapon of mass destruction has been highlighted in a recent FBI Bioterror report released last November entitled Terrorism 2002-2005 which states that "Ricin and the bacterial agent anthrax are emerging as the most prevalent agents involved in WMD investigations" (http://www.fbi.gov/publications/terror/terrorism2002_2005.pdf). Ricin toxin is a potent plant toxin that can be easily produced from abundantly available castor beans. Ricin toxin is highly toxic to humans and other mammals and is thought to be a bioterror threat because of its stability and high potency as well as the large worldwide reservoir created as a by-product of castor oil production. It is second only to botulinum toxin as the most lethal natural toxin. Exposure to small amounts of ricin 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 against 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 RiVax™

There are currently no vaccines available to prevent ricin poisoning or medical treatments to care for poisoning victims. A vaccine is considered by many to be the best way to prospectively protect populations at risk of exposure against ricin toxin. RiVax™ is a subunit vaccine based on the purified and genetically inactivated A chain of ricin toxin. This vaccine would potentially be added to the Strategic National Stockpile and dispensed in the event of a terrorist attack. Prior Phase 1 clinical trial results for RiVax™ demonstrated that the vaccine is well tolerated and induces antibodies in humans that neutralize the ricin toxin. The functional activity of the antibodies was confirmed by animal challenge studies in mice that survived exposure to ricin toxin after being injected with serum samples from the volunteers. The program is being funded by grants from NIAID, which have totaled over $11 million in direct funding to DOR.

About DOR BioPharma, Inc.

DOR BioPharma, Inc. (DOR) is a late-stage biopharmaceutical company developing products to the treat life-threatening side effects of cancer treatments and serious gastrointestinal diseases, and to create vaccines for certain bioterrorism agents. DOR's lead product, orBec® (oral beclomethasone dipropionate or BDP), is a potent, locally acting corticosteroid being developed for the treatment of gastrointestinal Graft-versus-Host disease (GI GVHD), a common and potentially life-threatening complication of bone marrow transplantation. DOR filed a New Drug Application for orBec® with the FDA for the treatment of acute GI GVHD and received a not approvable letter in which the FDA has requested data from a confirmatory Phase 3 clinical trial to demonstrate the safety and efficacy of orBec®. A Marketing Authorization Application with the European Medicines Evaluation Agency has also been validated and is under review. orBec® is currently the subject of a National Institutes of Health-supported, Phase 2, randomized, double-blind, placebo-controlled trial in the prevention of acute GVHD. Oral BDP may also have application in treating other gastrointestinal disorders characterized by severe inflammation. DOR has initiated a development program with its Lipid Polymer Micelle (LPM™) drug delivery technology for the oral delivery of leuprolide for the treatment of prostate cancer and endometriosis, as well as a development program with its oral azathioprine technology for the treatment of oral GVHD.

Through its Biodefense Division, DOR is developing biomedical countermeasures pursuant to the 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 well tolerated and immunogenic in a Phase 1 clinical trial in normal volunteers.

For further information regarding DOR BioPharma, Inc., please visit the Company's website located at 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 US Government or other countries, that the US 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: the FDA's requirement that DOR conduct additional clinical trials to demonstrate the safety and efficacy of orBec® will take a significant amount of time and money to complete and positive results leading to regulatory approval cannot be assumed; 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; orBec® may not gain market acceptance if it is eventually approved by the FDA; 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.