Soligenix Announces Positive Preliminary Results from its Phase 2 Clinical Trial of SGX942 for the Treatment of Oral Mucositis in Head and Neck Cancer Patients

Princeton, NJ – December 16, 2015 – Soligenix, Inc. (OTCQB: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, announced today positive results in its Phase 2 clinical trial, in which SGX942, a first-in-class Innate Defense Regulator (IDR), at a dose of 1.5 mg/kg, successfully reduced the median duration of severe oral mucositis by 50% in all patients and by 67% in patients receiving the most aggressive chemoradiation therapy (CRT) for treatment of their head and neck cancer.

This exploratory study achieved all objectives, including identifying a best dose of 1.5 mg/kg. The study enrolled 111 patients across three SGX942 dose groups (i.e., 1.5, 3.0, and 6.0 mg/kg) and a placebo group and evaluated patients undergoing CRT for head and neck cancer. In the 1.5 mg/kg treatment group, the median duration of severe oral mucositis was decreased by 50%, from 18 days to 9 days (p=0.099), meeting the prospectively defined statistical threshold of p<0.1 in the study protocol. Further, patients receiving the most aggressive CRT in this dose group had even more striking reductions in their median duration of severe oral mucositis of 67%, from 30 days to 10 days (p=0.040). Clinicians are most concerned about severe oral mucositis, which includes patients who cannot eat and/or drink due to their mouth ulcers.

In addition to the oral mucositis findings, a trend towards increased incidence of “complete response” of tumor at the one month follow up visit was observed (47% in placebo vs. 63% in SGX942 at 1.5 mg/kg). Decreases in mortality and significant decreases in infection rate were also observed with SGX942 treatment and are being further evaluated. In the preliminary analysis, SGX942 was found to be generally safe and well tolerated, consistent with the safety profile observed in the prior Phase 1 study conducted in 84 healthy volunteers. Long-term follow-up evaluations are ongoing with final results expected in the fourth quarter of 2016. Data from this Phase 2 trial is expected to be submitted for future presentation and publication.

One of the leading investigators in oral mucositis, Stephen T. Sonis, DMD, DMSc, Professor of Oral Medicine at Harvard School of Dental Medicine and Member of the Soligenix Oral Mucositis Medical Advisory Board noted, “Oral mucositis is a devastating side effect of CRT used for the treatment of head and neck cancers, which compromises patients’ tolerability of therapy and quality of life, and adds to health and economic burdens associated with care.  Despite intense efforts to develop effective interventions for CRT-induced mucositis, there are currently no approved drugs.  SGX942 is the first Innate Defense Regulator in development for oral mucositis.  The favorable results noted in this trial demonstrate the validity of a novel treatment approach which targets critical biological events leading to mucositis and strongly support further trials.  The clinical results are consistent with preclinical animal studies in which SGX942 reduced duration of oral mucositis by approximately 50% following either chemotherapy or radiation therapy.”

“We are extremely pleased with the findings from the first Phase 2 study of SGX942.  The study met all of its objectives of defining the best dose, the most appropriate clinical endpoint, and patient population to use in future pivotal trials,” stated Richard Straube, MD, Senior Vice President and Chief Medical Officer of Soligenix. “The positive and clinically meaningful effect observed on the duration of ulcerative and severe oral mucositis clearly demonstrates the significant biologic activity that SGX942 exerts on this catastrophic side-effect of cancer treatment. The impact of SGX942 on other clinically beneficial outcomes (e.g., tumor control and infection rates) confirms the animal model data that, in treating patients’ oral mucositis, SGX942 may also prove to have a positive impact on their head and neck cancer.”

“After years of development, it is truly gratifying to witness this transformational event, in which the potential of the IDR technology begins to be translated into the clinical setting,” stated B. Brett Finlay, PhD, University of British Columbia, Peter Wall Distinguished Professor, CIFAR Senior Fellow Michael Smith Laboratories and co-founder of the IDR technology.  “With their unique mechanism of action, IDRs have the potential to not only mitigate oral mucositis, but also address the increasing problem of emerging and antibiotic resistant bacterial infections.”

“We are very excited with the outcome of this Phase 2 clinical study,” stated Christopher J. Schaber, PhD, President and Chief Executive Officer of Soligenix. “Given the positive and compelling preliminary data generated in oral mucositis, where there is substantial market potential, we will now look to engage the US Food and Drug Administration (FDA) on the size and scope of a pivotal Phase 2/3 clinical program since the data suggest that a pivotal trial could potentially be designed of a size roughly similar to the completed trial. Simultaneous with this activity, we will be aggressively pursuing opportunities for partnership to support subsequent clinical trials with SGX942. With the biologic activity of the IDR technology now confirmed in humans, we will also look to expand its potential utility in the infectious disease space.”

Dr. Schaber continued, “With the successful completion of the Phase 2 oral mucositis study, we now direct clinical efforts to the quality execution of our pivotal Phase 3 clinical trial in cutaneous T-cell lymphoma (CTCL) with SGX301, which was recently opened for enrollment. CTCL is a high priority disease indication, having received fast track and orphan designation from the FDA, and has the potential to support marketing registration in the US and the rest of the world.”

About Oral Mucositis

Mucositis is the clinical term for damage done to the mucosa by anticancer therapies. It can occur in any mucosal region, but is most commonly associated with the mouth, followed by the small intestine.  It is estimated, based upon review of historic published studies and reports and an interpolation of data on the incidence of mucositis, that mucositis affects approximately 500,000 people in the US per year and occurs in 40% of patients receiving chemotherapy. Mucositis can be severely debilitating and can lead to infection, sepsis, the need for parenteral nutrition and narcotic analgesia. The gastrointestinal damage causes severe diarrhea. These symptoms can limit the doses and duration of cancer treatment, leading to sub-optimal treatment outcomes.

The mechanisms of mucositis have been extensively studied and have been recently linked to the interaction of chemotherapy and/or radiation therapy with the innate defense system.  Bacterial infection of the ulcerative lesions is now regarded as a secondary consequence of dysregulated local inflammation triggered by therapy-induced cell death, rather than as the primary cause of the lesions.

It is estimated, based upon review of historic published studies and reports and an interpolation of data on the incidence of oral mucositis, that oral mucositis in head and neck cancer is a subpopulation of approximately 90,000 patients in the US, with a comparable number in Europe.  Oral mucositis almost always occurs in patients with head and neck cancer treated with chemoradiation therapy (>80% incidence of severe mucositis) and is common (40-100% incidence) in patients undergoing high dose chemotherapy and hematopoietic cell transplantation, where the incidence and severity of oral mucositis depends greatly on the nature of the conditioning regimen used for myeloablation.

Oral mucositis in head and neck cancer remains an area of unmet medical need where there are currently no approved drug therapies.

About SGX942

SGX942 is an innate defense regulator (IDR), a new class of short, synthetic peptides. It has a novel mechanism of action in that it modulates the body’s reaction to both injury and infection towards an anti-inflammatory and an anti-infective response.  IDRs have no direct antibiotic activity but, by modulating the host’s innate immune system responses, increase survival after infections with a broad range of bacterial Gram-negative and Gram-positive pathogens. It also accelerates resolution of tissue damage following exposure to a variety of agents including bacterial pathogens, trauma and chemo- and/or radiation therapy.  SGX942 has demonstrated safety in a Phase 1 clinical study in healthy human volunteers and efficacy in numerous animal disease models including mucositis, colitis, melioidosis and other bacterial infections.  Recently, SGX942 has demonstrated preliminary efficacy in an exploratory Phase 2 clinical study in patients with oral mucositis due to chemoradiation (CRT) therapy for head and neck cancer. Consistent with preclinical findings, SGX942 demonstrated improvements in both the duration of oral mucositis and the incidence of infection, as well as a trend towards improved tumor response to CRT therapy.

SGX942 and related analogs have a strong intellectual property position, including composition of matter.  SGX942 was developed pursuant to discoveries made by Professors B. Brett Finlay, PhD and Robert Hancock, PhD of the University of British Columbia, Canada and approximately $40 million has been put towards its development to date, inclusive of government grants.
SGX942 has received fast track designation from the US Food and Drug Administration (FDA) for the treatment of oral mucositis as a result of radiation and/or chemotherapy treatment in head and neck cancer patients.  Fast track is a designation that the FDA reserves for a drug intended to treat a serious or life-threatening condition and one that demonstrates the potential to address an unmet medical need for the condition.  Fast track designation is designed to facilitate the development and expedite the review of new drugs.  For instance, should events warrant, Soligenix will be eligible to submit a new drug application (NDA) for SGX942 on a rolling basis, permitting the FDA to review sections of the NDA prior to receiving the complete submission.  Additionally, NDAs for fast track development programs ordinarily will be eligible for priority review, which imparts an abbreviated review time of approximately six months.

 About Soligenix, Inc.

 Soligenix is a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need. Our BioTherapeutics business segment is developing SGX301 as a first-in-class photodynamic 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 and infectious disease.

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 SGX943, our melioidosis therapeutic candidate. 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).

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, including SGX942, 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. Positive results from the Phase 2 study evaluating SGX942 does not ensure that the follow-on Phase 2/3 clinical study will be successful. 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.