Soligenix Demonstrates Robust Stability Results with its SGX204 Anthrax Vaccine

Soligenix Demonstrates Robust Stability Results with its SGX204 Anthrax Vaccine


PRINCETON, N.J., Jan. 18, 2012 /PRNewswire/ -- Soligenix, Inc. (OTCBB: SNGX) (Soligenix or the Company), a development stage biopharmaceutical company, announced today results from long-term stability studies of its proprietary DNI (dominant negative inhibitor) anthrax rPA (recombinant protective antigen) subunit protein vaccine, known as SGX204. SGX204 is a hyperimmunogenic derivative of PA and is being developed as a vaccine to protect against anthrax disease either as a pre-exposure prophylactic vaccine or post-exposure vaccine.

Positive stability was demonstrated when DNI rPA was subjected to temperatures as high as 70 degrees Celsius for one month.  In that case, DNI rPA retained native configuration with no evidence of denaturation that typically occurs in water buffers under the same thermal conditions. Redundant methods to determine protein structure each yielded results that indicated that the thermally stressed DNI protein retained completely native conformation after exposure to 70C. The water free DNI protein was formulated with common excipients that allow for preservation of protein structure in the dried state. Long-term stability of DNI rPA was also demonstrated after refrigerated storage for more than 7 years. More importantly, when DNI rPA was combined with a potent adjuvant formulation, animals vaccinated with the combination developed high titer neutralizing antibodies that confer protection against anthrax disease. 

"We are very excited about these extraordinary stability results," stated Robert N. Brey, PhD, Chief Scientific Officer of Soligenix. "We believe that the combination of long-term stability over several years with stability at such elevated temperatures has the potential to confer a distinct advantage over other anthrax vaccine technologies currently in development. Further, SGX204 is highly immunogenic and thereby offers the potential for complete immunization with just one or two doses. As with any biodefense product, our goal is to have SGX204 stockpiled by the US government."

About SGX204                Soligenix has entered into to a field-exclusive option agreement with Harvard University to negotiate a license under patent rights that cover prophylactic uses of a modified anthrax toxin protein. Initial development work will be covered pursuant to a previously issued $9.4 million National Institute of Allergy and Infectious Disease (NIAID) grant enabling development of thermo-stable ricin and anthrax vaccines. The option encompasses an issued U.S. patent that covers engineered variants of protective antigen developed in the Harvard Medical School laboratory of Dr. John Collier.  Protective antigen is the principal determinant of protective immunity to anthrax. Soligenix believes that it will be able to develop the Collier anthrax vaccine with an efficacy profile superior to other anthrax vaccines.

About Anthrax                           Anthrax is an acute infectious disease that is easily transmitted to humans by environmentally durable spores that are produced by Bacillus anthracis. Because the spores are robust and contagious, anthrax is considered a Category A bioterror threat. Anthrax infection can occur in three forms: cutaneous (skin), inhalation, and gastrointestinal. Inhaled spores can cause a rapidly progressing form of anthrax since the spores are transported to lymph nodes near the lungs where they germinate, releasing vegetative bacteria into the bloodstream. Bacteria synthesize a complex series of toxin components that make up anthrax toxin, resulting in overwhelming toxemia that causes shock and organ failure. Treatment of anthrax involves long-term antibiotic therapy, since ungerminated spores can lie dormant in the lungs for up to 60 days. Only a few inhaled spores can cause inhalational anthrax. Once the toxin has entered the bloodstream, antibiotics are ineffective, and only toxin-specific therapy is effective. Passively transferred antibodies can neutralize anthrax toxins and can be used post-exposure in conjunction with antibiotics. Because of the long residence time of spores in the lung, it is possible to vaccinate post-exposure, but the onset of neutralizing antibodies must occur during the period of antibiotic therapy.

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 conducting a National Cancer Institute (NCI)-supported Phase 1/2 clinical trial of SGX201 in the prevention of acute radiation enteritis. Additionally, Soligenix is developing SGX203 for the treatment of pediatric Crohn's disease.

Through its Biodefense Division, Soligenix is developing countermeasures pursuant to the Project BioShield Act of 2004. Soligenix's biodefense products in development are a recombinant subunit vaccine called RiVaxTM, which is designed to protect against the lethal effects of exposure to ricin toxin and SGX204, a vaccine against anthrax exposure. RiVaxTM has been shown to be well tolerated and immunogenic in a Phase 1 clinical trial in normal volunteers. Both RiVaxTM and SGX204 are currently the subject of a $9.4 million National Institute of Allergy and Infectious Disease (NIAID) grant supporting development of new heat stable vaccines. Soligenix is also developing SGX202 for the treatment of gastrointestinal acute radiation syndrome (GI ARS) and has recently released positive preliminary preclinical 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, including orBec®, SGX201, SGX202, SGX203, SGX204, RiVaxTM, and LPMTM, 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 cash expenditures will not exceed projected levels, 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 Data Safety Monitoring Board's recent determination disclosed in our Form 8-K dated September 15, 2011 recommending that Soligenix stop its confirmatory Phase 3 clinical trial of orBec® in acute GI GVHD and the likelihood that: the FDA will  require that Soligenix conduct additional clinical trials to demonstrate the safety and efficacy of orBec® which will take a significant amount of time and money to complete and positive results leading to regulatory approval cannot be assumed; Soligenix 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®. Factors affecting the development and use of SGX201, SGX202, SGX203, SGX204, RiVaxTM and LPMTM are similar to those affecting orBec®. These and other 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.