Soligenix Announces Positive Preliminary Nonclinical Results in Macrophage Activation Syndrome

Princeton, NJ – January 5, 2015 – Soligenix, Inc. (OTCQB: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company developing products that address unmet medical needs in the areas of inflammation, oncology and biodefense, announced today that preliminary efficacy in an animal model of Macrophage Activation Syndrome (MAS) has been demonstrated with its SGX94 innate defense regulator (IDR) technology, significantly mitigating the pancytopenia characteristic of MAS.

MAS is a rare and potentially fatal complication of certain childhood rheumatological disorders that is thought to be caused by the over activation and unregulated production of certain cells of the immune system, namely, macrophages and T lymphocytes, leading them to attack the body’s own cells and tissues.  MAS occurs in about 10% of individuals with chronic rheumatic diseases including systemic juvenile idiopathic arthritis (SJIA).  MAS is characterized by pancytopenia, which is an abnormal reduction in the number of red blood cells, white blood cells, and platelets in the blood, as well as liver insufficiency, coagulopathy and neurologic symptoms.  Mortality in this disease is estimated at 10-20%.

In animal models where MAS is induced by repeated Toll-like receptor-9 (TLR-9) stimulation, SGX94 was shown to mitigate the disease characteristic pancytopenia by significantly increasing both white blood cell (p=0.01) and platelet (p<0.001) counts in the SGX94 treated animals as compared to placebo treated animals.  This initial work was conducted in collaboration with Edward Behrens, MD, Chief of Rheumatology at the Children’s Hospital of Philadelphia (CHOP) who has established the preclinical model of MAS.

“MAS is a potentially fatal complication of a number of rheumatic, oncologic, infectious and genetic disorders,” stated Dr. Behrens.  “For example, 10% of patients with Systemic Juvenile Idiopathic Arthritis will develop fulminant, life-threatening MAS.  SGX94 has demonstrated efficacy in improving outcomes in our mouse model of MAS, improving cytokine-storm induced cytopenia in these animals.  I look forward to continuing to work with the Soligenix team to further evaluate the utility of SGX94 in this rare syndrome.”

“The efficacy of SGX94 in this animal model of MAS further confirms the broad potential of the IDR platform across multiple inflammatory and infectious diseases, particularly in light of the excellent safety profile observed with SGX94 to date in humans,” stated Christopher J. Schaber, PhD, President and Chief Executive Officer of Soligenix.  “Soligenix will continue to evaluate the potential clinical applicability of SGX94 in MAS as well as other indications.  Soligenix will also pursue government grant support to fund the further development of this rare and serious inflammatory complication.”

About Macrophage Activation Syndrome

MAS is characterized by a highly stimulated but ineffective immune response; however, its pathogenesis is poorly understood.  MAS has many similarities with that of the other forms of hemophagocytic lymphohistiocytosis (HLH). MAS is a life-threatening complication of rheumatic disease that, for unknown reasons, occurs much more frequently in individuals with systemic juvenile idiopathic arthritis (SJIA).  Besides SJIA, systemic lupus erythematosus (SLE), and Kawasaki disease are two other rheumatologic conditions in which MAS appears to occur somewhat more frequently than in other diseases.  In adults, based on some limited epidemiologic studies, MAS is seen most frequently in association with adult onset Still’s disease, SLE, and various vasculitic syndromes.  MAS is characterized by pancytopenia, liver insufficiency, coagulopathy and neurologic symptoms and is thought to be caused by the activation and uncontrolled proliferation of T lymphocytes and well-differentiated macrophages, leading to widespread hemophagocytosis and cytokine overproduction.  Despite treatment, fatalities still occur with a mortality rate in the range of 10-20%.

About SGX94

SGX94 is an innate defense regulator (IDR), a new class of short, synthetic peptides that has a novel mechanism of action in that it has simultaneous anti-inflammatory and anti-infective activity.  IDRs have no direct antibiotic activity but modulate host responses, increasing survival after infections with a broad range of bacterial Gram-negative and Gram-positive pathogens, as well as accelerating resolution of tissue damage following exposure to a variety of agents including bacterial pathogens, trauma and chemo- and/or radiation therapy.  SGX94 has demonstrated safety in a Phase 1 clinical study in healthy human volunteers and efficacy in animal disease models including mucositis, colitis, skin infection and other bacterial infections.  A Phase 2 clinical study evaluating SGX94 (SGX942) in oral mucositis in patients with head and neck cancer is ongoing.

About Soligenix, Inc.

Soligenix is a late-stage biopharmaceutical company developing products that address unmet medical needs in the areas of inflammation, oncology and biodefense. Our BioTherapeutics business segment is developing SGX301 as a first-in-class photo-dynamic therapy utilizing safe visible light for the treatment of cutaneous T-cell lymphoma, proprietary formulations of oral beclomethasone 17,21-dipropionate (BDP) for the prevention/treatment of gastrointestinal (GI) disorders characterized by severe inflammation including pediatric Crohn’s disease (SGX203) and acute radiation enteritis (SGX201), and our novel innate defense regulator technology (SGX942) for the treatment of oral mucositis.

Our Vaccines/BioDefense business segment includes active development programs for RiVax™, our ricin toxin vaccine candidate, VeloThrax™, our anthrax vaccine candidate, OrbeShield™, our GI acute radiation syndrome therapeutic candidate and SGX101 and SGX943, our melioidosis therapeutic candidates. The development of our vaccine programs incorporates the use of our proprietary heat stabilization platform technology, known as ThermoVax™.  Currently, this business segment is supported with up to $57 million in government grant and contract funding from the National Institute of Allergy and Infectious Diseases (NIAID) and the Biomedical Advanced Research and Development Authority (BARDA).  Additionally, Soligenix has an exclusive worldwide collaboration with Intrexon Corporation (NYSE: XON) focused on the joint development of SGX101 for the treatment for melioidosis.

For further information regarding Soligenix, Inc., please visit the Company’s Website at www.soligenix.com.

This press release may contain 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.