Soligenix Announces Initiation of a Phase 2 Clinical Trial of orBec® for the Treatment of Chronic GI GVHD Clinical Trial Supported by $300,000 NCI Grant

Princeton, NJ – December 2, 2013 – Soligenix, Inc. (OTCQB: SNGX) (Soligenix or the Company), a clinical stage biopharmaceutical company focused on developing products to treat serious inflammatory diseases where there remains an unmet medical need, as well as developing several biodefense vaccines and therapeutics, announced today that it has initiated a Phase 2, randomized, double-blind, placebo-controlled study evaluating orBec® (oral beclomethasone 17,21-dipropionate or BDP) as a treatment for the gastrointestinal (GI) manifestations of chronic Graft-versus-Host disease (GVHD). The study is partially funded by the National Cancer Institute (NCI) which has awarded Soligenix a Small Business Innovation Research (SBIR) grant to support the conduct of a Phase 2 clinical trial.  The award provides Soligenix with approximately $300,000 over a two-year period.

The Phase 2 study is designed as a multicenter, pilot study enrolling patients that have received allogeneic hematopoietic cell transplantation (HCT) at least 100 days earlier, have documented chronic GVHD in at least one organ outside the GI tract, and have a mucosal biopsy consistent with GI GVHD.  The primary efficacy objective of the study is to estimate the proportion of subjects with chronic GVHD with GI involvement who achieve a complete response, partial response or minimal response of GI GVHD signs and symptoms when treated with orBec® for up to 16 weeks. Response will be assessed using a composite score based on the symptoms of satiety, nausea/vomiting, and anorexia.

“Survival of patients undergoing allogeneic HCT has markedly improved over the last decade, leading to a growing number of long-term survivors with chronic GVHD.  In these patients, gastrointestinal GVHD can be a persistent problem whether layered on top of extraintestinal chronic GVHD or dominating the clinical picture”, stated George B. McDonald, MD, Member, Fred Hutchinson Cancer Research Center and Professor of Medicine at the University of Washington.  “Based on the pharmacology of orally-delivered BDP, which delivers a potent glucocorticoid directly to the GI mucosa, orBec® offers a promising option to address disabling GI symptoms in patients with chronic GVHD.”

“We are pleased by the continued support of NCI as a collaborator supporting our oncology focused BDP clinical programs,” stated Christopher J. Schaber, PhD, President and Chief Executive Officer of Soligenix. “We look forward to working with our clinical centers to complete this study as soon as possible to continue development of orBec® with the aim of addressing this orphan disease.”

About Chronic GVHD

Graft-versus-Host disease (GVHD) is a major complication of allogeneic hematopoietic cell transplantation. GVHD is an inflammatory disease initiated by T cells in the donor graft that recognize histocompatibility and other tissue antigens of the host, and is mediated by a variety of effector cells and inflammatory cytokines. GVHD presents in both acute and chronic forms, and each is commonly associated with inflammation of gastrointestinal mucosa along with symptoms of anorexia, nausea, vomiting, and diarrhea. The symptoms of chronic GVHD typically present at between 100 days and three years post-transplant.

Chronic GVHD has features resembling autoimmune and other immunologic disorders such as scleroderma, Sjögren syndrome, primary biliary cirrhosis, wasting syndrome, bronchiolitis obliterans, immune cytopenias and chronic immunode?ciency. The manifestations of chronic GVHD may be restricted to a single organ or tissue or may be widespread.  Chronic GVHD can lead to debilitating consequences, e.g., joint contractures, loss of sight, end-stage lung disease, or mortality resulting from profound chronic immune suppression leading to recurrent or life-threatening infections.  Gastrointestinal (GI) GVHD in patients with chronic GVHD can lead to persistent symptoms, weight loss, and malabsorption of nutrients.

Treatment of chronic GVHD is a challenge because it can be refractory to frontline immunosuppression.  High-dose systemic corticosteroids are used with some success but carry significant toxicity. The risks of prolonged immunosuppression include local and disseminated infections, Epstein-Barr virus associated lymphoproliferative disease, hypothalamic-pituitary-adrenal (HPA) axis suppression, myopathy, glucose intolerance, neuropsychiatric disease and bone demineralization. One of the goals of therapy of chronic GVHD is to minimize systemic immune suppression by treating involved organs with topical therapy whenever possible.

It is estimated, based upon review of historic published studies and reports and an interpolation of data on the incidence of chronic GVHD, that there are 6,000 patients annually in the US, with a comparable number in Europe that suffer from chronic GVHD.

About orBec®

orBec® represents a first-of-its-kind oral, locally acting therapy tailored to treat the GI manifestation of chronic GVHD, the organ system where GVHD is most frequently encountered and highly problematic. orBec® is intended to reduce the need for systemic immunosuppressive drugs such as prednisone to treat chronic GI GVHD. The active ingredient in orBec® is beclomethasone dipropionate (BDP), a highly potent, topically active corticosteroid that has a local effect on inflamed tissue.  BDP has been marketed in the US and worldwide since the early 1970s as the active pharmaceutical ingredient in a nasal spray and in a metered-dose inhaler for the treatment of patients with allergic rhinitis and asthma.  orBec® is specifically formulated for oral administration as a single product consisting of two tablets, one immediate release tablet providing BDP to the upper sections of the GI tract and one delayed release tablet providing BDP to the lower sections of the GI tract.

In addition to issued patents and pending worldwide patent applications held by or exclusively licensed to Soligenix, orBec® has received orphan drug designation in the US for the treatment of chronic GI GVHD. Orphan drug designations provide for 7 years of market exclusivity upon approval in the US.

About Soligenix, Inc.

Soligenix is a clinical stage biopharmaceutical company developing products to treat serious inflammatory diseases where there remains an unmet medical need, as well as developing several biodefense vaccines and therapeutics. Soligenix is developing proprietary formulations of oral BDP (beclomethasone 17,21-dipropionate) for the prevention/treatment of gastrointestinal disorders characterized by severe inflammation, including pediatric Crohn’s disease (SGX203), acute radiation enteritis (SGX201) and chronic Graft-versus-Host disease (orBec®), as well as developing its novel innate defense regulator (IDR) technology SGX942 for the treatment of oral mucositis.

Through its BioDefense Division, Soligenix is developing countermeasures pursuant to the Biomedical Advanced Research and Development Authority (BARDA) Strategic Plan of 2011-2016 for inclusion in the US government’s Strategic National Stockpile. Soligenix’s lead 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 VeloThrax™, a vaccine against anthrax exposure. RiVax™ has been shown to be well tolerated and immunogenic in two Phase 1 clinical trials in healthy volunteers. Both RiVax™ and VeloThrax™ are currently the subject of a $9.4 million National Institute of Allergy and Infectious Diseases (NIAID) grant supporting development of Soligenix’s new vaccine heat stabilization technology known as ThermoVax™.  Soligenix is also developing OrbeShield™ for the treatment of gastrointestinal acute radiation syndrome (GI ARS) under a BARDA contract award valued up to $26.3 million and a NIAID contract award valued up to $6.4 million. OrbeShield™ has previously demonstrated statistically significant preclinical survival results in a canine model of GI ARS funded by the NIAID.  Recently, Soligenix announced a worldwide exclusive collaboration with Intrexon Corporation that will focus on the joint development of a treatment for Melioidosis, a high priority biothreat and an area of unmet medical need.

For further information regarding Soligenix, Inc., please visit the Company’s Website at https://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, including but not limited to, potential market sizes, patient populations and clinical trial enrollment.  Statements that are not historical facts, such as “anticipates,” “estimates,” “believes,” “intends,” “potential,” 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, achieve regulatory approval for or commercialize products based on its technologies, particularly in light of the significant uncertainty inherent in developing vaccines against bioterror threats conducting preclinical and clinical trials of vaccines, obtaining regulatory approvals and manufacturing vaccines, 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 funding to support product development and commercialization efforts, including grants and awards, maintain its existing grants which are subject to performance requirements, enter into any biodefense procurement contracts with the US Government or other countries, that it will be able to compete with larger and better financed competitors in the biotechnology industry, that changes in health care practice, third party reimbursement limitations and Federal and/or state health care reform initiatives will not negatively affect its business, or that the US Congress may not pass any legislation that would provide additional funding for the Project BioShield program.  These and other risk 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.