Soligenix Announces Positive Survival Results of SGX202 in Radiation Injury

Princeton, NJ – February 21, 2012 – Soligenix, Inc. (OTCBB: SNGXD) (Soligenix or the Company), a development stage biopharmaceutical company, announced today further promising preliminary results from its continuing preclinical study of SGX202 (oral beclomethasone dipropionate or BDP) in a canine gastrointestinal acute radiation syndrome (GI ARS) model. The new study results indicate that dogs treated with SGX202 starting 24 hours after exposure to lethal doses of total body irradiation (TBI) demonstrated statistically significant (p=0.04) improvement in survival when compared to control dogs. This study builds upon the previous results which showed statistically significant survival in dogs when dosing of SGX202 was initiated two hours after lethal doses of TBI.

These results demonstrate once again that SGX202 has the potential to reduce the inflammatory cytokine storm induced by the radiation damaged GI tract. The GI tract is extremely sensitive to radiation injury. GI damage is the major cause of rapid mortality during high dose radiation exposure, such as could be encountered during nuclear accidents or with the use of dirty bombs. Gut injury from high dose radiation is associated with epithelial cell damage and hypoperfusion of the intestine, which stimulates a vigorous local and systemic inflammatory response.

The aim of the study was to determine whether SGX202 could improve survival and GI recovery beginning 24 hours after TBI using a well-established GI ARS dog model. Six dogs were exposed to TBI (12 Gy administered at 70 cGy/min), and then given autologous bone marrow and SGX202 with supportive care; four dogs were used as controls and not treated with SGX202.  Autologous bone marrow was given to reduce the duration and impact of the radiation-induced hematopoietic syndrome and allow for a focus on measures to treat the GI effects of TBI.  SGX202 was administered 24 hours after TBI and daily until GI recovery (up to day 100 post exposure).  Median survival post TBI exposure in the control group was 8 days, compared to greater than 87 days in the SGX202 treated group.  These results demonstrate that SGX202 has the potential to reduce the local inflammation in the radiation damaged GI tract.  Analysis of the full dataset from this study remains ongoing and is anticipated to be published in a peer reviewed journal.

“These 24 hour post-exposure results confirm earlier findings and suggest that SGX202 may significantly improve survival from GI ARS,” stated George Georges, MD, Associate Member of the Clinical Research Division at Fred Hutchinson Cancer Research Center and Principal Investigator for the study. “SGX202 may potentially inhibit the cellular and innate immune mechanisms within the gut mucosa that exaggerate mucosal damage, and improve GI recovery after radiation. In the challenging area of radiation injury, the second study also met its primary objective in protecting dogs from GI ARS and extending their survival. We are completing our analysis of the data so that we may extend our investigations of SGX202 in GI recovery after radiation exposure and build upon these promising results.”

“We are very pleased with the results to date with SGX202 in GI ARS,” Christopher J. Schaber, PhD, Chief Executive Officer of Soligenix. “Based on these data and our positive preliminary interactions with both the National Institute of Allergy and Infectious Diseases (NIAID) and the Biomedical Advanced Research and Development Authority (BARDA), it is our intent to continue to seek additional funding for the continued development of SGX202.”

The study was supported by a $1 million grant from the NIAID.

About GI ARS

The potential occurrence of industrial radiation accidents and the threat of terrorist events involving radioactive material mandate the development and implementation of effective treatments of radiation injury. The GI tract is highly sensitive to radiation damage. Substantial injury to the GI tract after radiation exposure results in death. In most radiation scenarios, injury to the hematopoietic system and gastrointestinal tract are the main determinants of survival. There is an urgent need to develop specific countermeasures against the lethality caused by intestinal exposure to radiation and against the pathophysiological manifestations of radiation-induced gastrointestinal injury.

About SGX202

SGX202 contains BDP, a highly potent, topically active corticosteroid that has a local effect on inflamed tissue. SGX202 is formulated for oral administration in GI ARS patients as a single product consisting of two tablets; one tablet is intended to release BDP in the proximal portions of the GI tract, and the other tablet is intended to release BDP in the distal portions of the GI tract.  BDP has been marketed in the United States and worldwide since the early 1970s as the active pharmaceutical ingredient in inhalation products for the treatment of patients with allergic rhinitis and asthma. Oral BDP may also have application in treating other GI disorders characterized by severe inflammation such as Crohn’s Disease and radiation enteritis.

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 RiVax™, which is designed to protect against the lethal effects of exposure to ricin toxin and SGX204, 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 SGX204 are currently the subject of a $9.4 million National Institute of Allergy and Infectious Disease (NIAID) grant supporting development of vaccine heat stabilization technology known as ThermoVaxTM. Soligenix is also developing SGX202 for the treatment of gastrointestinal acute radiation syndrome (GI ARS) and has demonstrated 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, RiVax™, ThermoVax™, 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, RiVax™, ThermoVax™, 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.