Soligenix Announces Collaboration with Infectious Disease Research Institute to Develop Thermostabilized Biodefense Vaccines Utilizing Novel Adjuvants

Princeton, NJ – June 27, 2012 – Soligenix, Inc. (OTCBB: SNGX) (Soligenix or the Company), a development stage biopharmaceutical company, announced today that it has entered into a collaboration with the Infectious Disease Research Institute (IDRI) of Seattle, WA to develop select biodefense vaccines using IDRI’s potent and safe synthetic adjuvants in conjunction with Soligenix’s proprietary subunit proteins and thermostability platform (known as ThermoVax™).  Synthetic adjuvants are immunologically active compounds that are added to vaccines to aid in the induction of enhanced protective immune responses.  IDRI has state of the art expertise in developing and formulating a range of adjuvants that have proven capable of enhancing the level and breadth of cellular and humoral immune responses to a variety of vaccine antigens.  The combination of these technologies has the potential to result in vaccines with robust characteristics for long-term stability and rapid onset of protective immunity,   desired features of vaccines that would be stockpiled for emergency use.

The first developmental objective of the collaboration is to assess the combination of one of IDRI’s adjuvant compounds that has been shown to enhance the generation of high titer neutralizing antibodies to anthrax toxin with Soligenix’s second generation DNI (Dominant Negative Inhibitor) subunit protein anthrax vaccine candidate, known as VeloThrax™. VeloThrax™ is Soligenix’s hyperimmunogenic derivative of anthrax rPA (recombinant protective antigen), a candidate vaccine to protect against anthrax disease. Concurrently, the second developmental objective is to assess the combination of an IDRI adjuvant with formulations of RiVax™, Soligenix’s vaccine against ricin toxin under development. The goal for both vaccines is to achieve stable products that will promote rapid onset of protective immunity in humans to minimize the number of vaccinations required for protective immunity.

“IDRI is enthusiastic about working with Soligenix to support their efforts in developing their anthrax and ricin vaccine candidates, and are highly confident that IDRI’s adjuvant technology can help build effective vaccines,” said Darrick Carter PhD, IDRI’s Vice President of Adjuvant Technology. “These new candidate vaccines could be the critical solution in providing protection to people in the event there is a bioterror threat from the release of anthrax or ricin toxins.”

The initial work of this collaboration is to be carried out under Soligenix’s existing $9.4 million National Institute of Allergy and Infectious Disease (NIAID) grant supporting development of advanced heat stable vaccines against anthrax and ricin toxins. The objectives of this work are consistent with the development of product enhancements that the National Institutes of Health (NIH) has advocated for effective biodefense vaccines: long shelf life, rapid onset of immunity, post exposure prophylaxis, and surge capacity for production. For conventional vaccines, achievement of those objectives will also provide solutions that ameliorate problems with cold storage of vaccines. A recent report by the Department of Health and Human Services (DHHS) entitled “Vaccines for Children Program: Vulnerabilities in Vaccine Management,” demonstrates the need for thermostable vaccines to eliminate the need for cold chain manufacture and storage. Excursions from cold chain temperatures lead to the inactivation of vaccines, thereby putting recipients of vaccines at risk. Together, IDRI and Soligenix are pursuing additional government development funding to further support this work.

“We are very pleased to be able to enter into a partnership of this type with IDRI,” stated Christopher J. Schaber, PhD, President and Chief Executive Officer of Soligenix. “IDRI possesses novel R&D, manufacturing and technical expertise in the field of adjuvants.  We believe that with the addition of IDRI’s potent adjuvants to our hyperimmunogenic anthrax and ricin toxin vaccines, we will have the potential to develop highly competitive biodefense vaccines that can address the exact needs of the US government with regard to rapid onset immunity with just one or two doses.  As with any biodefense program, our goal is to have VeloThrax™ and RiVax™ stockpiled by the US government in its strategic national stockpile.”

About IDRI

The Infectious Disease Research Institute (IDRI) is a Seattle-based not-for-profit organization committed to applying innovative science to the research and development of products to prevent, detect, and treat infectious diseases of poverty. By integrating capabilities, including early stage drug discovery, preclinical testing, manufacturing, and clinical trials, IDRI strives to create an efficient pathway bringing scientific innovation from the laboratory to the people who need it most. IDRI is the recipient of numerous grants from the Pharmaceutical industry, the US government, and the Bill & Melinda Gates Foundation for the development of new drugs, vaccines and related technologies. For more information, visit www.idri.org.

About Soligenix, Inc.

Soligenix is a development stage biopharmaceutical company developing products to treat life-threatening side effects of cancer treatments and serious gastrointestinal diseases, and vaccines for certain bioterrorism agents. Soligenix’s lead product, orBec® (oral beclomethasone dipropionate), is a potent, locally acting corticosteroid that has been initially developed for the treatment of acute gastrointestinal Graft-versus-Host disease (GI GVHD), a common and potentially life-threatening complication of hematopoietic cell transplantation. Soligenix is also developing oral BDP for the prevention/treatment of other gastrointestinal disorders characterized by severe inflammation, including acute radiation enteritis (SGX201), which is the subject of a recently completed National Cancer Institute (NCI)-supported Phase 1/2 clinical trial and pediatric Crohn’s disease (SGX203).

Through its BioDefense Division, Soligenix is developing countermeasures pursuant to the Project BioShield Act of 2004. 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 a Phase 1 clinical trial in normal volunteers. Both RiVax™ and VeloThrax™ are currently the subject of a $9.4 million National Institute of Allergy and Infectious Disease (NIAID) grant supporting development of new thermostable vaccine technology known as ThermoVax™. Soligenix is also developing OrbeShield™ for the treatment of gastrointestinal acute radiation syndrome (GI ARS) and has demonstrated statistically significant preclinical survival results in a canine GI ARS model.

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. Statements that are not historical facts, such as “anticipates,” “believes,” “intends,” 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 or commercialize products based on its technology, 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 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, 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.