Soligenix Announces Publication of Results of its Phase 2 Clinical Trial of orBec® in the Prevention of Acute GVHD

PRINCETON, N.J., Dec. 12, 2011 /PRNewswire/ -- Soligenix, Inc. (Soligenix or the Company) (OTC BB: SNGX), a development stage biopharmaceutical company, announced the publication of results from its investigator-initiated Phase 2 "proof-of-concept" exploratory clinical trial of orBec® for the prevention of acute Graft-versus-Host disease (GVHD) in patients undergoing myeloablative conditioning regimens with initiation of dosing prior to hematopoietic cell transplantation (HCT) and continuing through the post-transplantation period. The article is entitled "Evaluation of Oral Beclomethasone Dipropionate for the Prevention of Acute Graft-versus-Host Disease" and is posted online in Biology of Blood and Marrow Transplantation.

As previously reported, orBec® appears safe and well tolerated in this patient population, but did not achieve statistical significance in the primary endpoint, which was the proportion of subjects who developed acute GVHD with severity sufficient to require systemic immunosuppressive treatment on or before day 90 after transplantation. As detailed in the article, this result was possibly due to poor patient compliance with administration of study drug which was lower than anticipated with only 54% of patients taking at least 90% of study drug within 4 weeks of transplantation.

It was noted that poor compliance in the study may be associated with the incidence of oral mucositis, as a lower severity of oral mucositis was highly correlated with better compliance (p <0.0001). Compliance was also better in patients who did not require systemic treatment for GVHD in the orBec® arm (p = 0.001) compared to those in the placebo arm (p = 0.98), consistent with the possibility that reduced adherence may have compromised the orBec® treatment effect. Among the 50 orBec® patients with at least 90% compliance, 54% required systemic treatment for GVHD, versus 65% of the 26 placebo patients with at least 90% compliance. The mean cumulative dose of prednisone was 28.8 mg/kg among all orBec® patients with at least 90% compliance, versus 37.1 mg/kg among all placebo patients with at least 90% compliance. For the group with less than 90% compliance, the mean cumulative prednisone dose was the same in both arms.

Kevin Horgan, MD, Chief Medical Officer of Soligenix commented, "Upon deeper analysis of the data from the Phase 2 prevention study, we find that poor overall patient compliance may have played a role in the equivocal primary endpoint result. This observation is interesting and consistent with the previously reported overall decrease in the incidence of the more severe grades of GVHD and indicative of a preventive effect for orBec® in this setting. However, I would caution that this analysis is exploratory and needs to be analyzed in light of the failure of the recent Phase 3 treatment clinical trial in acute gastrointestinal GVHD to achieve its primary endpoint. We will provide information on the future of the overall GVHD program once the data from the Phase 3 trial has been fully analyzed."

The Phase 2 prevention study was a randomized, double-blind, placebo-controlled trial that enrolled 140 patients who had been randomized to either orBec® or placebo at a 2:1 ratio. Prior to HCT, patients began study drug at the start of their conditioning regimen and continued through day 75 following HCT. The study was conducted primarily at the Fred Hutchinson Cancer Research Center in Seattle, WA and was supported, in large part, by a National Institutes of Health (NIH) grant. The impetus for this NIH-funded prevention study came from two double-blind, randomized, placebo-controlled trials showing that orBec® was effective and safe as a treatment for acute gastrointestinal GI GVHD.

About GVHD

GVHD is a debilitating and painful disease. It is a common disorder among immunocompromised cancer patients after receiving allogeneic stem cell or bone marrow transplants. Unlike organ transplants where the patient's body may reject the organ, in GVHD it is the donor cells that begin to attack the patient's body – most frequently the gut, liver and skin. Patients with mild-to-moderate GI GVHD typically develop symptoms of anorexia, nausea, vomiting and diarrhea. If left untreated, GI GVHD can progress to ulcerations in the lining of the GI tract, and in its most severe form, can be fatal.

Systemic immunosuppressive agents such as prednisone, which are the current standard treatments for GVHD, are associated with high mortality rates due to infection and debility. Further, these drugs have not been approved for treating GVHD in the US or European Union, but rather are used off-label for this indication.

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 has a Lipid Polymer Micelle (LPM™) drug delivery technology for the oral delivery of leuprolide for the treatment of prostate cancer and endometriosis.

Through its BioDefense division, Soligenix is developing countermeasures pursuant to the Project BioShield Act of 2004. Soligenix's lead biodefense product in development is a recombinant subunit vaccine called RiVax™, which is designed to protect against the lethal effects of exposure to ricin toxin. RiVax™ has been shown to be well tolerated and immunogenic in a Phase 1 clinical trial in normal volunteers. RiVax™ is 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 radiation injury and has recently released positive preliminary preclinical results in a canine gastrointestinal acute radiation syndrome 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, RiVax™, 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, RiVax™ 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.