Soligenix Submits NIAID Contract Proposal for Development of a Thermostable Ricin Vaccine

PRINCETON, N.J., Oct. 31, 2013 /PRNewswire/ -- Soligenix, Inc. (OTCQB: SNGX) (Soligenix or the Company), a clinical stage biopharmaceutical company focused on developing products to treat inflammatory diseases and biodefense medical countermeasures (MCMs) where there remains an unmet medical need, announced today submission of a full contract proposal to the National Institute of Allergy and Infectious Diseases (NIAID), Division of Microbiology and Infectious Diseases.  Successful award of the proposal would support a multi-year, multi-million dollar contract for the advanced development of RiVax™ as a vaccine MCM candidate for biodefense threats to protect the public. 

Soligenix submitted this proposal to NIAID in response to Broad Agency Announcement (BAA) NIAID-DMID-NIHAI2013174, "Development of Vaccine Formulations Effective Against NIAID Priority Pathogens." NIAID is interested in supporting the advanced development of candidate vaccines against potentially lethal pathogens and toxins which consist of a dry formulation technology to enhance stability and minimize cold chain storage or preservative requirements. 

To date, the development of RiVax™ has been largely supported through a series of overlapping grants from both the NIAID and Food and Drug Administration (FDA), granted to Soligenix and to the University of Texas Southwestern Medical Center (UTSW) where vaccine development originated.

"We are pleased to submit our proposal to NIAID, who has been the main supporter of our thermostable ricin toxin vaccine development since its inception," stated Christopher J. Schaber, PhD, President and Chief Executive Officer of Soligenix. "Although there are no guarantees, we believe that the combination of our ricin toxin vaccine, RiVax™ and our ThermoVax™ heat stabilization platform technology aligns well with the mission objectives of NIAID.  In addition, our organizational structure and experience allows Soligenix to be a valuable strategic partner for NIAID, as well as with the other agencies we currently work with."

The submission of our proposal is non-binding and does not guarantee the award of a NIAID contract.  The contract award will require a favorable technical, scientific and business review by NIAID followed by negotiation of fair and reasonable contract terms.

About RiVax™

RiVax™ is Soligenix's proprietary recombinant subunit vaccine developed to protect against exposure to ricin toxin. With RiVax™, Soligenix is a world leader in the area of ricin toxin vaccine research.

RiVax™ contains a genetically altered version of ricin A chain containing two mutations that inactivate the inherent toxicity of the ricin molecule. The Phase 1A clinical trial was conducted with a formulation of RiVax™ that did not contain an adjuvant. That trial revealed dose dependent seroconversion as well as lack of toxicity of the molecule when administered intramuscularly to human volunteers. The adjuvant-free formulation of  RiVax™ induced toxin neutralizing antibodies that lasted up to 127 days after the third vaccination in several individuals.  To increase the longevity and magnitude of toxin neutralizing antibodies, RiVax™ was formulated with an adjuvant of aluminum salts (known colloquially as Alum) for the Phase 1B clinical trial.  Alum is an adjuvant that is used in many human vaccines, including most vaccines used in infants. In preclinical animal studies, the Alum formulation of RiVax™ induced higher titers and longer lasting antibodies than the adjuvant-free vaccine. 

The development of RiVax has been sponsored through a series of overlapping grants from both the NIAID and FDA, which were granted to Soligenix and to UTSW where the vaccine originated. To date, Soligenix and UTSW have collectively received approximately $25 million in grant funding from the NIAID for development of RiVax and related vaccine technologies.

About ThermoVax

ThermoVax™ is a novel, proprietary method of rendering Alum-adjuvanted vaccines stable at elevated temperatures. Alum is the most widely employed adjuvant technology in the vaccine industry. The value of ThermoVax™ lies in its potential ability to eliminate the need for cold chain production, transportation, and storage for Alum adjuvanted vaccines. This would relieve companies of the high costs of producing and maintaining vaccines under refrigerated conditions.  Based on historical reports from the World Health Organization and other scientific reports, a meaningful proportion of vaccine doses globally are wasted due to excursions from required cold chain temperature ranges. This is due to the fact that most aluminum adjuvanted vaccines need to be maintained at between 2 and 8 degrees Celsius and even brief excursions from this temperature range (especially below freezing) usually necessitates the destruction of the product or the initiation of costly stability programs specific for the vaccine lots in question.  The savings realized from the elimination of cold chain costs and related product losses would in turn significantly increase the profitability of vaccine products. Elimination of the cold chain would also further facilitate the use of these vaccines in the lesser developed parts of the world. ThermoVax™ has the potential to facilitate easier storage and distribution of strategic national stockpile vaccines in emergency settings.

ThermoVax™ development is currently being supported pursuant to our $9.4 million NIAID grant enabling development of thermostable ricin (RiVax™) and anthrax (VeloThrax™) vaccines. Proof-of-concept preclinical studies with ThermoVax™ indicate that it is able to produce stable vaccine formulations using adjuvants, protein immunogens, and other components that ordinarily would not withstand long temperature variations exceeding customary refrigerated storage conditions. These studies were conducted with our aluminum-adjuvanted ricin toxin vaccine, RiVax™, made under precise lyophilization conditions using excipients that aid in maintaining native protein structure of the ricin A chain, the immunogenic compound of the vaccine. When RiVax™ was kept at 40 degrees Celsius for six months, all of the animals vaccinated with the lyophilized RiVax™ vaccine developed potent and high titer neutralizing antibodies. Confirmatory results have extended the stability to six months when the vaccine is kept at 40 degrees Celsius. In contrast, animals that were vaccinated with the liquid RiVax™ vaccine kept at 40 degrees Celsius did not develop neutralizing antibodies and were not protected against ricin exposure. The ricin A chain is extremely sensitive to temperature and rapidly loses the ability to induce neutralizing antibodies when exposed to temperatures higher than 8 degrees Celsius.

The underlying lyophilization technology was discovered by Drs. John Carpenter and Theodore Randolph at the University of Colorado, the inventors of the technology underlying the ThermoVaxTM products. 

About Ricin Toxin

The Centers for Disease Control has classified ricin toxin as a Category B biological agent. Currently, there are no FDA approved therapeutics or vaccines that can be used to protect against ricin exposure or to reverse its effects once exposed. Ricin toxin is a protein that consists of an A and B subunit that can be extracted from the beans of the castor plant, Ricinus communis. The potential use of ricin toxin as a biological weapon of mass destruction has been highlighted in an FBI Bioterror report released in November 2007, entitled Terrorism 2002-2005, which states that "Ricin and the bacterial agent anthrax are emerging as the most prevalent agents involved in Weapons of Mass Destruction (WMD) investigations."

The toxic effects of ricin are caused by its ability to inhibit protein synthesis. Ricin's potency is due to its promiscuity, intoxicating all known cell types, and extremely efficient enzymatic activity. Ricin can be introduced into the body through inhalation of an aerosol, or through ingestion, injection or infusion. While ricin is second in toxicity only to botulinum toxin, it is far easier to obtain, prepare, and use.  Because of the high content of ricin in castor beans, ricin toxin can be extracted from the mash produced as a by-product of castor oil production (castor oil is found in many commonly used substances such as paints, varnishes, and lubricating oils, and is also used as a purgative) by several simple enrichment steps and, therefore is easy to stockpile. Recent economic surveys have shown that there are over 1 million tons of castor beans produced in the world annually. The global commercial production has the potential to yield approximately 50,000 tons of pure ricin. The fate of much of this ricin in countries outside of the US is unknown.

Once exposed to lethal doses of ricin, death is irreversible after four hours and takes three to five days to kill an individual. The current expectation that drives vaccine development of RiVax™ is that ricin is most likely to be distributed as an aerosol form, since it is highly lethal by this route. There are currently no effective means to prevent the effects of ricin intoxication.  In recent years, Al Qaeda branches in Yemen and the Arabian Peninsula have threatened the use of ricin toxin to poison food and water supplies and in connection with explosive devices.  Domestically, the threat from ricin remains a concern for security agencies.  As recently as April 2013, letters addressed to the President, a US Senator and a judge tested positive for ricin.

About Soligenix, Inc.

Soligenix is a clinical stage biopharmaceutical company developing products to treat serious inflammatory diseases where there remains an unmet medical need, as well as developing several biodefense vaccines and therapeutics. Soligenix is developing proprietary formulations of oral BDP (beclomethasone 17,21-dipropionate) for the prevention/treatment of gastrointestinal disorders characterized by severe inflammation, including pediatric Crohn's disease (SGX203), acute radiation enteritis (SGX201) and chronic Graft-versus-Host disease (orBec®), as well as developing its novel innate defense regulator (IDR) technology SGX942 for the treatment of oral mucositis.  

Through its BioDefense Division, Soligenix is developing countermeasures pursuant to the Biomedical Advanced Research and Development Authority (BARDA) Strategic Plan of 2011-2016 for inclusion in the US government's Strategic National Stockpile. Soligenix's lead biodefense products in development are a recombinant subunit vaccine called RiVax™, which is designed to protect against the lethal effects of exposure to ricin toxin and VeloThrax™, a vaccine against anthrax exposure. RiVax™ has been shown to be well tolerated and immunogenic in two Phase 1 clinical trials in healthy volunteers. Both RiVax™ and VeloThrax™ are currently the subject of a $9.4 million National Institute of Allergy and Infectious Diseases (NIAID) grant supporting development of Soligenix's new vaccine heat stabilization technology known as ThermoVax™.  Soligenix is also developing OrbeShield™ for the treatment of gastrointestinal acute radiation syndrome (GI ARS) under a BARDA contract award valued up to $26.3 million and a NIAID contract award valued up to $6.4 million. OrbeShield™ has previously demonstrated statistically significant preclinical survival results in a canine model of GI ARS funded by the NIAID.  Recently, Soligenix announced a worldwide exclusive collaboration with Intrexon Corporation that will focus on the joint development of a treatment for Melioidosis, a high priority biothreat and an area of unmet medical need.

For further information regarding Soligenix, Inc., please visit the Company's website at www.soligenix.com.

This press release contains forward-looking statements that reflect Soligenix, Inc.'s current expectations about its future results, performance, prospects and opportunities, including but not limited to, potential market sizes, patient populations and clinical trial enrollment.  Statements that are not historical facts, such as "anticipates," "estimates," "believes," "intends," "potential," or similar expressions, are forward-looking statements.  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.  Soligenix cannot assure you that it will be able to successfully develop, achieve regulatory approval for or commercialize products based on its technologies, particularly in light of the significant uncertainty inherent in developing vaccines against bioterror threats conducting preclinical and clinical trials of vaccines, obtaining regulatory approvals and manufacturing vaccines, 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 funding to support product development and commercialization efforts, including 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 it will be able to compete with larger and better financed competitors in the biotechnology industry, that changes in health care practice, third party reimbursement limitations and Federal and/or state health care reform initiatives will not negatively affect its business, or that the US Congress may not pass any legislation that would provide additional funding for the Project BioShield program.  These and other risk factors are described from time to time in filings with the Securities and Exchange Commission, including, but not limited to, Soligenix's reports on Forms 10-Q and 10-K.  Unless required by law, Soligenix assumes no obligation to update or revise any forward-looking statements as a result of new information or future events.

SOURCE Soligenix, Inc.



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