Soligenix Announces Publication of Positive Data Describing Protection from Mucosal and Systemic Ricin Intoxication by Intradermal RiVax Administration

Preclinical data demonstrate the potential for intradermal delivery of RiVax(TM)

PRINCETON, N.J., June 25 /PRNewswire-FirstCall/ -- Soligenix, Inc. (OTC Bulletin Board: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company, announced today the publication of an article in the June 2010 edition of Vaccine, which describes protection from mucosal and systemic ricin intoxication by intradermal administration of RiVax(TM), the Company's vaccine against ricin toxin. The article was authored by the Company's collaborators at the University of Texas Southwestern Medical Center at Dallas (UT Southwestern) where the vaccine originated. RiVax(TM) is currently being evaluated in Phase 1 human safety and immunogenicity trials, as well as non-human primate trials for efficacy.
 

The purpose of this study was to determine whether RiVax(TM) administered by intradermal (ID) injection would be more immunogenic and protective at lower doses. ID vaccination has several practical advantages in protecting humans due to the ease of administration, especially when using an ID gun, thereby eliminating the need for needles and subsequent needle disposal. In this publication, a comparison of ID and intramuscular (IM) vaccination with or without an aluminum salt adjuvant at several dose levels was investigated. The levels of anti-RiVax(TM) antibodies generated in serum as well as the ability of the vaccine to protect mice against ricin intoxication following systemic, gastric gavage or aerosol challenges were determined.
 

  The major findings to emerge from this study are as follows:

  1. ID vs. IM administration of RiVax(TM) without adjuvant conferred equal
     protection;
  2. RiVax(TM) adsorbed to aluminum adjuvant was significantly better than
     RiVax(TM) alone in eliciting specific antibodies, resulting in both
     systemic and mucosal protection when 90-99% less vaccine was used;
  3. Vaccination with RiVax(TM) adsorbed to aluminum adjuvant via the ID
     route was significantly better than vaccination via the IM route at
     protecting animals from ricin challenge, hence, smaller doses of
     vaccine may be required when ID vaccination is used;
  4. In comparing IM vs. ID vaccination with RiVax(TM)  adsorbed to aluminum
     adjuvant at low doses, the latter was more effective at protecting mice
     from ricin-induced lung damage; and
  5. RiVax(TM) specific antibody levels correlated with post challenge
     survival.

"There have been many attempts to develop a prophylactic ricin vaccine, using different preparations of the ricin holotoxin with and without various adjuvants," stated Dr. Ellen Vitetta, Director of the Cancer Immunobiology Center at UT Southwestern and senior author of the study. "But none of these have been as extensively studied as RiVax(TM) and none have looked at the ID vaccination route."
 

"Since it is likely that a ricin vaccine would be used in an emergency setting or by the military, the ease of ID vaccination with jet injectors or similar devices with lower doses of vaccine is rather important," stated Robert N. Brey, PhD, Chief Scientific Officer of Soligenix. "It should also be noted that ID vaccination was highly effective at protecting the lungs of the mice from ricin aerosols, a likely route of delivery in the setting of bioterrorism."
 

The article, entitled "Intradermal administration of RiVax(TM) protects mice from mucosal and systemic ricin intoxication," was authored by Drs. Marconescu, Smallshaw, Pop, Ruback, and Vitetta at UT Southwestern. The research was funded directly by an NIH grant to UT Southwestern and complements the NIH funding to Soligenix for the development of RiVax(TM). The full article (Marconescu et. al., "Intradermal administration of RiVax protects mice from mucosal and systemic ricin intoxication," Vaccine) is available online at http://dx.doi.org/10.1016/j.vaccine.2010.05.045
 

About RiVax(TM)
 

RiVax(TM) is Soligenix's proprietary vaccine developed to protect against exposure to ricin toxin and is the most advanced vaccine in the company's portfolio. RiVax(TM) induces a protective immune response in animal models of ricin exposure and is currently being evaluated in humans. One human Phase 1 clinical trial has been completed and a second trial is currently being conducted.
 

Results of the first Phase 1 clinical trial of RiVax(TM) indicated that the immunogen was safe and induced antibodies anticipated to protect humans from ricin exposure. The outcome of the study was published in the Proceedings of the National Academy of Sciences (Vitetta et al., 2006, PNAS, 105:2268-2273). The second trial, sponsored by UT Southwestern, is currently evaluating a more potent formulation of RiVax(TM). Soligenix has developed processes for large-scale manufacturing and is further establishing correlates of the human immune response in non-human primates.
 

The development of RiVax(TM) has been sponsored through a series of overlapping challenge grants (UC1) and cooperative grants (U01) from the NIH, granted to Soligenix and to UT Southwestern where the vaccine originated. The second clinical trial is being supported by a grant to UT Southwestern from the US Food and Drug Administration's Office of Orphan Products Development. Soligenix and UT Southwestern have collectively received approximately $25 million in grant funding from the NIH for development of RiVax(TM) and related vaccine technologies.
 

About Ricin Toxin
 

Ricin toxin is a plant toxin thought to be a bioterror threat because of its stability and high potency as well as the large worldwide reservoir created as a by-product of castor oil production. Exposure to ricin results in local tissue necrosis, and general organ failure leading to death within several days of exposure. The potential use of ricin toxin as a biological weapon has been highlighted in an FBI terrorism report, which states that "Ricin and the bacterial agent anthrax are emerging as the most prevalent agents involved in WMD investigations" (http://www.fbi.gov/publications/terror/terrorism2002_2005.pdf).
 

There are currently no effective means to prevent the effects of ricin intoxication. The successful development of an effective vaccine against ricin toxin may act as a deterrent against the actual use of ricin as a biological weapon and could be used in rapid deployment scenarios in the event of a biological attack. RiVax(TM) would potentially be added to the Strategic National Stockpile and dispensed in the event of a terrorist attack.
 

About Soligenix, Inc.
 

Soligenix, Inc. (Soligenix) is a late-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 or BDP), is a potent, locally acting corticosteroid being developed for the treatment of acute gastrointestinal Graft-versus-Host-Disease (GI GVHD), a common and potentially life-threatening complication of hematopoietic cell transplantation. orBec® is currently the subject of a confirmatory Phase 3 clinical trial for the treatment of acute GI GVHD and an NIH-supported, Phase 2, randomized, double-blind, placebo-controlled trial in the prevention of acute GVHD. Soligenix has also recently initiated an NIH-supported Phase 1/2 clinical trial of SGX201 in the prevention of acute radiation enteritis. Additionally, Soligenix has a Lipid Polymer Micelle (LPM(TM)) drug delivery technology for the oral delivery of leuprolide for the treatment of prostate cancer and endometriosis.
 

Through its Biodefense Division, Soligenix is developing biomedical countermeasures pursuant to the Project BioShield Act of 2004. Soligenix's lead biodefense product in development is a recombinant subunit vaccine called RiVax(TM), which is designed to protect against the lethal effects of exposure to ricin toxin. RiVax(TM) has been shown to be well tolerated and immunogenic in a Phase 1 clinical trial in normal volunteers. RiVax(TM) is also the subject of a $9.4 million NIH grant received by the Company supporting development of new heat stable vaccines.
 

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, RiVax(TM), and LPM(TM), 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 risks that: the FDA's requirement that Soligenix conduct additional clinical trials to demonstrate the safety and efficacy of orBec® 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 and LPM(TM) 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.

CONTACT: Company Contact, Evan Myrianthopoulos, Chief Financial Officer
of Soligenix, Inc., +1-609-538-8200
 

Web Site: http://www.soligenix.com/
 

Posted: June 2010

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