Soligenix, Inc. (OTC Bulletin Board: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company, announced today that the United States Patent and Trademark Office (USPTO) has granted patent #7,829,668, entitled "Compositions and methods for modifying toxic effects of proteinaceous compounds." This patent includes composition claims for the modified ricin toxin A chain which is the immunogen contained in RiVax™. Conceived by Soligenix's collaborative partner Ellen Vitetta PhD, Director of the Cancer Immunobiology Center and colleagues at the University of Texas Southwestern Medical Center in Dallas (UT Southwestern), 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 issued patent contains claims that describe alteration of sequences within the ricin A chain that affect vascular leak, one of the deadly toxicities caused by ricin toxin. Ricin is a potent plant toxin that is composed of two molecular chains; the A chain, which contains several sites that inactivate cellular machinery and induce its characteristic toxicity, and the B chain which causes it to bind to cells with high affinity. The issued patent contains claims for specific mutations in this site that induce vascular leak syndrome (VLS). The combination of mutations in each of the key sites for ricin toxicity ensures that the recombinant subunit will not produce this devastating effect. Studies conducted by Dr. Vitetta 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.
This patent is the third patent in the family related to defined alterations in the VLS site. The first two patents in this family, US patents #6,566,500 and #6,960,652, also entitled "Compositions and methods for modifying toxic effects of proteinaceous compounds," issued in 2003 and 2005 respectively.
"This patent issuance is another milestone towards obtaining broad patent coverage for RiVax™," said Robert N. Brey, PhD, Chief Scientific Officer of Soligenix. "We continue to be enthusiastic about the prospects of developing a ricin vaccine to anticipate civilian and military biodefense requirements. We believe the technology that Dr. Vitetta and her colleagues at UT Southwestern have developed for RiVax™ is the most advanced in this area."
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