Soligenix Announces Results of Recent Data Safety Monitoring Board Review for Phase 3 orBec® Study in Acute GI GVHD

Soligenix to Host Investor Conference Call Today at 9AM EDT

PRINCETON, N.J., Sept. 15, 2011 -- /PRNewswire/ -- Soligenix, Inc. (OTCBB: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company, announced that an independent Data Safety Monitoring Board (DSMB) recently completed a pre-specified interim analysis for safety and futility for Soligenix's confirmatory Phase 3 clinical trial of orBec® an oral formulation of beclomethasone dipropionate (BDP) in acute gastrointestinal Graft-versus-Host disease (GI GVHD).

The DSMB recommended that the study be stopped as it is highly unlikely to achieve the predetermined primary objective of efficacy based on the interim results. No safety concerns were raised. As a result of the DSMB's recommendation, patient enrollment in the study will stop and the data will be analyzed.

"We are obviously disappointed with the outcome of the DSMB's review," stated Christopher J. Schaber, PhD, President and Chief Executive Officer of Soligenix. "Over the coming weeks, we will be analyzing the data.  At this point, we do not know why the primary efficacy endpoint was not demonstrated by orBec®, as two prior studies with very similar designs demonstrated robust efficacy and clinically relevant results in essentially the same patient population. It is not possible at this exact time to determine what explains this unexpected outcome. One of a number of possibilities that will be investigated is that these results may be due to changes in the overall treatment practices of the allogeneic stem cell transplantation patient population that may have had an impact on the treatment effect of orBec® since the previous Phase 3 study was concluded in 2004. If there is any clarity gained from further analysis of the dataset, especially with respect to specific subsets of patients that may benefit from orBec® therapy, then we will certainly communicate our findings."  

Dr. Schaber continued, "With approximately $7.4 million of cash, we can continue to evaluate other clinical applications for oral BDP in the areas of radiation enteritis, radiation injury, and Crohn's disease. With continued additional funding under our $9.4 million NIH grant, we can also continue to pursue development of our heat stabilization technology for subunit vaccines including application to RiVaxTM, our vaccine against ricin toxin. Additionally, we will be instituting cost containment measures as we evaluate our strategic options, including whether to further pursue the applications of orBec® in the GVHD treatment and prevention space in light of the results of the recent Phase 3 clinical trial."

The Company will host a webcast and conference call today at 9AM EDT to review the DSMB recommendation. To participate in the conference call, please dial the following toll free number: (877) 407-3974. International callers may dial: (201) 689-8886. After prepared remarks by management, a question-and-answer session will follow. Listeners may also participate via webcast approximately 10 minutes prior to the start of the call by visiting the Soligenix website investor relations page at http://www.soligenix.com/invest_sec.shtml. The webcast is best viewed using Internet Explorer.

About orBec®

orBec®, oral beclomethasone dipropionate (oral BDP), was recently the subject of a confirmatory Phase 3 clinical trial in the treatment of acute GI GVHD which was stopped for futility. This Phase 3 trial, also referred to as the SUPPORTS protocol (Sparing Unnecessary Prednisone Phase 3 orBec® Randomized Treatment Study), enrolled 140 patients and was designed to confirm the clinically meaningful endpoints observed in previous Phase 2 and Phase 3 clinical studies. The primary endpoint was the treatment failure rate at Study Day 80. Analysis of this endpoint was positive as a secondary endpoint (p-value 0.005) in the Company's previous Phase 3 study as a clinically significant outcome following a 50-day course of treatment with orBec® (i.e., 30 days following cessation of treatment). The SUPPORTS trial was conducted at major transplant centers throughout the US, Europe, and Australia. The trial was the subject of a Special Protocol Assessment (SPA) agreement that the Company reached with the US Food and Drug Administration (FDA). It was determined in a pre-specified interim analysis that this study was unlikely to achieve the primary efficacy objective.

orBec® was the subject of two prior randomized, double-blind, placebo-controlled clinical trials in acute GI GVHD. The first study was a 60-patient Phase 2 single-center clinical trial conducted at the Fred Hutchinson Cancer Research Center, which demonstrated statistical significance in its primary endpoint of controlling GI GVHD (p-value 0.02). The second study was a 129-patient pivotal Phase 3 multi-center clinical trial conducted at 16 leading bone marrow/stem cell transplant centers in the US and France. Although orBec® did not achieve statistical significance in the primary endpoint of its pivotal trial, namely median time-to-treatment failure through Day 50 (p-value 0.1177), orBec® did achieve statistical significance in other key secondary endpoints such as the proportion of patients free of GVHD at Day 50 (p-value 0.05) and Day 80 (p-value 0.005) and the median time to treatment failure through Day 80 (p-value 0.0226), as well as a 66% reduction in mortality among patients randomized to orBec® at 200 days post-transplant with only 5 patient (8%) deaths in the orBec® group compared to 16 patient (24%) deaths in the placebo group (p-value 0.0139).  At one year post-randomization in the Phase 3 trial, 18 patients (29%) in the orBec® group and 28 patients (42%) in the placebo group died within one year of randomization (46% reduction in mortality, p-value 0.04).

orBec® is formulated for oral administration 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.  Oral BDP may also have application in treating other GI disorders characterized by severe inflammation.

About 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), 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 (LPMTM) 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 RiVaxTM, which is designed to protect against the lethal effects of exposure to ricin toxin. RiVaxTM has been shown to be well tolerated and immunogenic in a Phase 1 clinical trial in normal volunteers. RiVaxTM is currently the subject of a $9.4 million 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.