Soligenix reports Phase 2 clinical trial results of orBec for GVHD

Soligenix, Inc. (Soligenix or the Company) (OTC Bulletin Board: SNGX), a late-stage biopharmaceutical company, today reported preliminary results from its 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 preliminary results indicate that 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.  However, an encouraging result was that use of orBec® resulted in fewer cases of more severe acute GVHD grades IIb-IV (21% vs. 33% of patients receiving placebo), although this difference was not statistically significant.  This result has the potential to be clinically relevant because GVHD grades IIb-IV are associated with more severe disease involving the skin and liver as well as being associated with poorer outcomes, including mortality rates that approach 100% in the grade IV patient population.  Further analysis of the complete dataset continues and is aimed at identifying other potential effects seen with orBec® in preventing acute GVHD.

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.  

Paul J. Martin, MD, Principal Investigator for the Phase 2 study and a Member, Fred Hutchinson Cancer Research Center stated, "Trials with orBec® have shown a consistent and positive clinical response in the treatment of acute GI GVHD.  We therefore designed a trial to determine whether orBec® could be used to prevent GVHD. Preliminary analysis indicates that administration of orBec®  starting before transplantation did not provide a statistically significant clinical advantage in preventing acute GVHD in this study, possibly because of confounding factors associated with the chemotherapy or radiation.  Preventive administration of orBec® to reduce the incidence or severity of GVHD warrants further investigation, for example, by starting orBec® dosing after transplantation, closer to the initial inflammatory insult of acute GVHD.  We are continuing to analyze the data in order to gain a better understanding of potential preventive treatment effects in this patient population and to determine the best approach for subsequent study."   

Dr. Martin continued, "In my mind, the results from this prevention study have no clinical implication regarding the likelihood of success in the ongoing Phase 3 study of orBec® for the treatment of acute GI GVHD."

"This Phase 2 clinical trial was truly proof-of-concept and the first of its kind. It was an aggressive approach to determining if a topically-active steroid therapy, like orBec®, could have an impact on preventing the development of GVHD very early in the disease process," added Brian L. Hamilton, MD, PhD, Chief Medical Officer of Soligenix.  "The trend towards less severe acute GVHD in the patients treated with orBec® is encouraging. We are continuing to analyze the Phase 2 data for other clinically meaningful signals."

Dr. Hamilton continued, "We obviously remain confident in the ultimate success of our confirmatory Phase 3 study of orBec® in the treatment of acute GI GVHD. This Phase 3 trial is anchored by more than 15 years of clinical research in the treatment setting, including positive results from two prior randomized, double-blind, placebo-controlled studies.  The current Phase 3 study is designed to replicate the endpoint of treatment failure rate at Study Day 80, which was successfully measured as a secondary endpoint (p-value 0.005) in the Company's previous Phase 3 study.  Accordingly, there is no correlation between the prospects for success in these distinctly different therapeutic indications and patient populations.  We continue to make good progress towards completing the confirmatory Phase 3 trial in treatment of acute GI GVHD in the second half of next year."