DOR BioPharma Achieves Manufacturing Milestone In Development of RiVax(TM);

Miami, FL - DOR BioPharma, Inc. recently announced that it has successfully completed the second development milestone for its ricin vaccine, called RiVax(TM), under the Challenge Grant previously awarded to DOR in September 2004 by the National Institute of Allergy and Infectious Diseases (NIAID), a unit of the National Institutes of Health. For the second milestone, the Company has completed the development of a process for large-scale manufacture of the key vaccine ingredient consisting of a modified ricin toxin subunit protein. In addition, supplementary characterization and formulation objectives have been achieved.

DOR is developing the vaccine under the Challenge Grant in conjunction with the University of Texas Southwestern Medical Center, Stanford Research Institute, University of Kansas, and Cambrex Biosciences in Baltimore. This consortium led by DOR has resulted in development of a robust and reproducible manufacturing process and purification scheme for large-scale production of the ricin A chain subunit protein ingredient in RiVax(TM). This process will be sufficient to supply millions of vaccine doses. The ricin A chain is the catalytic subunit of ricin toxin that accounts for its main ability to inhibit protein synthesis and kill mammalian cells. Modification of the A chain to remove toxicity sites was required to make a vaccine safe enough and effective enough for use in humans. An early formulation of RiVax(TM) using a smaller scale process has been evaluated in a Phase I clinical trial in healthy volunteers, the first time such a vaccine has been tested in humans. The major results of that trial will be announced next week and discussed in publication.

Based on the improved production methods and high yields of RiVax(TM), DOR is manufacturing clinical batches which will be evaluated in additional human studies to examine the effect of the formulation and vaccination regimen on the human immune response. Continuing studies in animals are focused on correlating the level of antibodies in serum with protection against ricin exposure to various routes of exposure, including aerosol and oral. The demonstration of the functionality of human antibodies and passive protection in animals is a key step in providing evidence of efficacy under the FDA Animal Efficacy rule. Under this rule, the FDA can permit human licensure of a vaccine by relying on results from animal trials when human trials cannot ethically evaluate efficacy.

"We are very pleased with the progress we continue to make with our ricin program," stated Michael T. Sember, DOR's CEO and President. "We now have a well defined and scalable manufacturing process that is suitable for all future commercial needs as we continue development of this important biodefense countermeasure. We will continue to work closely with our partners and NIAID to expeditiously develop a safe and efficacious ricin vaccine."

Ricin toxin is a potential bioterror threat due to its highly lethal toxicity in small doses, ease of manufacture, and ability to be aerosolized. Exposure to small amounts, especially by inhalation, can lead to lung damage, nausea, fever, abdominal pain, and death within several days. The need for protective countermeasures against ricin has been emphasized by its recent and continued use as a biological weapon. There currently are no FDA approved vaccines against ricin toxin.

SOURCE: DOR BioPharma, Inc.