Driving Towards Key Inflection Points

- Driving Towards Key Inflection Points

Two Pivotal Phase 3 Clinical Trials

provides mid-year update and guidance

NJ - July 19, 2018 - Soligenix, Inc. (Nasdaq: 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, today

issued an update letter from its President and Chief Executive Officer, Dr. Christopher J. Schaber. The content of this letter

Friends and Shareholders,

wanted to take this opportunity to provide a mid-year update, as well as to provide some further guidance on our development programs.

focus remains, first and foremost, on the quality execution of our two pivotal Phase 3 clinical trials, including SGX942 (dusquetide)

for the treatment of oral mucositis in head and neck cancer and SGX301 (synthetic hypericin) for the treatment of cutaneous T-cell

lymphoma (CTCL). In addition, we continue to advance the development of our heat stable ricin toxin vaccine (RiVax )

with the financial support of the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes

of Health (NIH), while we also continue to actively pursue non-dilutive funding to support our rare disease pipeline.

continue to make good progress in advancing our two (2) pivotal Phase 3 clinical programs.

thirty CTCL centers across the US are participating in this pivotal trial, which is targeted to enroll approximately 120 patients.

Although the trial begins with a double-blind, placebo-controlled portion (referred to as Cycle 1), all participants in the trial

eventually receive active study drug (referred to as Cycle 2) and an optional portion of the trial is available to them to continue

with SGX301 treatment (referred to as Cycle 3). We remain encouraged by the response to this trial and by the majority of patients

that have elected to continue into the optional open-label portion of the study. We continue to work closely with the Cutaneous

Lymphoma Foundation, as well as the National Organization for Rare Disorders.

CTCL development program has partial funding of approximately $1.5 million over two years from a Small Business Innovative Research

(SBIR) grant awarded by the NIH National Cancer Institute (NCI).

trial, referred to as the "DOM-INNATE" study (Dusquetide treatment in Oral Mucositis -

by modulating INNATE immunity), aims to evaluate the response of SGX942 in reducing the duration of severe oral mucositis,

in addition to other clinically meaningful measures, and incorporates feedback from the FDA as well as the EMA via the Scientific

Advice process. Scientific Advice from the EMA indicated that a single, double-blind, placebo-controlled Phase 3 study, if successful,

in conjunction with the positive results from the Phase 2 dose-ranging study, generally will be sufficient to support a marketing

authorization application for potential licensure in Europe. SGX942 is the first Innate Defense Regulator in development for oral

mucositis and has previously demonstrated positive results in a Phase 2 clinical trial.

is a new chemical entity with a novel mechanism of action whereby it modulates the body's reaction to both injury and infection

towards an anti-inflammatory and an anti-infective response. It also accelerates resolution of tissue damage following exposure

to a variety of agents including bacterial pathogens, trauma and chemo-and/or radiation therapy. Long-term follow-up data from

the Phase 2 trial, published in 2017, further indicated the safety and tolerability of SGX942 treatment, with a sustained trend

towards reduced mortality and increased tumor resolution compared to placebo. SGX942 has received Fast Track designation from

the FDA for the treatment of oral mucositis as a result of CRT in head and neck cancer patients as well as PIM designation from

anticipate that approximately fifty US and European oncology centers will be participating in this pivotal Phase 3 study, which

is targeted to enroll approximately 190 patients. Currently, the study is enrolling in the US, which includes a number of centers

that had previously participated in the Phase 2 study, with expansion into Europe anticipated to occur in the next several weeks.

oral mucositis development program has partial funding of approximately $1.5 million over two years from a SBIR grant awarded

by the NIH National Institute of Dental and Craniofacial Research (NIDCR).

are advancing the development of our thermostabilized ricin toxin vaccine, RiVax , with the support of up to $24.7

million over six years awarded by NIAID, where we have announced that biomarkers for RiVax testing have been successfully

identified, facilitating potential approval under the FDA Animal Rule. The FDA Animal Rule is applied to products where testing

in human clinical trials would be unethical, and in the case of ricin toxin, fatal. The Animal Rule combines safety studies in

humans and efficacy testing in animals to facilitate approval. Key to the application of the Animal Rule is the requirement to

establish a correlation between the immune response observed in clinical trials in healthy volunteers with the immune response

demonstrated in animal efficacy studies.

will continue to provide preclinical findings, as they become available, later this year. We also anticipate initiating a Phase

2 vaccine immunogenicity and safety study in healthy volunteers utilizing RiVax . In parallel, additional efficacy

studies in non-human primates are planned for initiation, enabling a larger database of biomarker correlates for correlation with

human clinical results. Identification of biomarkers that correlate protection between animal and human studies is a significant

accomplishment in the RiVax development program. In addition to being protective and thermostable, RiVax

has demonstrated that a reduced number of vaccinations may be required to establish protection, potentially utilizing only

two doses instead of three, and both vaccine regimens are planned to be tested in the Phase 2 study planned to begin this year.

has received Orphan Drug designations from both the FDA and EMA, and as a new chemical entity, upon approval, has the potential

to qualify for a biodefense Priority Review Voucher (PRV). PRVs are transferable and can be sold, with sales in recent years of

up to $350 million. Recent events, including a foiled bioattack with ricin in Germany, suggest that the RiVax

vaccine may be of increasing interest to multiple countries.

development work with the University of Hawai'i on a trivalent thermostabilized Ebola vaccine continues as planned with

the support of a $700,000 sub-award over five years from NIAID. The subunit vaccine offers broader coverage to different strains

of Ebola, as well as Marburg virus, and offers the potential for a simpler chain of custody with no refrigerated conditions required.

noted above, we aggressively pursue non-dilutive funding sources to support our rare disease pipeline. We have received two NIH

SBIR grant awards totaling approximately $3 million for two of our biotherapeutics development programs. We are also operating

under NIAID grant and contract awards of up to $25.4 million to support RiVax development and our collaboration

with the University of Hawai'i at Manoa for the development of a trivalent thermostabilized Ebola vaccine in our BioDefense

business segment. This non-dilutive funding continues to provide a meaningful offset to our development expenses while better

positioning us to more effectively manage our overall cash burn.

addition to the non-dilutive funding received, we recently completed an at the market registered direct offering of 8,932,038

shares of common stock at $1.03 together with warrants to purchase up to 3,572,815 shares of our common stock with an exercise

price of $2.25 per share. Our gross proceeds from these offerings, which include the exercise of the underwriter's over-allotment

option to purchase additional shares of common stock and warrants, were approximately $9.2 million before deducting offering expenses.

The lead investor was Altamont Pharmaceutical Holdings, LLC, a long, fundamental life science investor, and currently our largest

existing shareholder at approximately 13%.

believe that, given current development assumptions, the approximate $8.4 million in net proceeds coupled with our existing cash

on hand, which at the end of March 2018 was $6.4 million, and including our non-dilutive government funding, provides a cash runway

of at least 12 months. With this available funding, we are now positioned to achieve multiple potential key milestones across

our rare disease pipeline.

closing, thank you for your interest and your continued support of Soligenix. We look forward to a productive second half of 2018

as we further advance our development programs, and will strive to provide similar updates on a periodic basis moving forward.

Best wishes to you and your families for a happy and safe remainder of the summer!

Christopher J. Schaber

and Chief Executive Officer

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 novel photodynamic therapy utilizing

safe visible light for the treatment of cutaneous T-cell lymphoma, our first-in-class innate defense regulator (IDR) technology,

dusquetide (SGX942) for the treatment of oral mucositis in head and neck cancer, and 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).

Vaccines/BioDefense business segment includes active development programs for RiVax , our ricin toxin vaccine candidate,

OrbeShield , our GI acute radiation syndrome therapeutic candidate and SGX943, our therapeutic candidate for antibiotic

resistant and emerging infectious disease. The development of our vaccine programs incorporates the use of our proprietary heat

stabilization platform technology, known as ThermoVax . To date, this business segment has been supported with

government grant and contract funding from the National Institute of Allergy and Infectious Diseases (NIAID) and the Biomedical

Advanced Research and Development Authority (BARDA).

further information regarding Soligenix, Inc., please visit the Company's website at www.soligenix.com.

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," "hopes," "intends," "plans," "expects," "goal,"

"may," "suggest," "will," "potential," or similar expressions, are forward-looking