Soligenix - Advancing to Important

Soligenix - Advancing to Important

With Two Pivotal Phase 3 Clinical Trials

Company provides corporate update and

Princeton, NJ - January 14, 2020

- 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 is provided below.

Dear Friends and Shareholders,

Let me start by wishing you a Healthy and

Happy New Year! I wanted to take this opportunity to provide a corporate update, as well as some further guidance on our development

programs moving forward.

It is truly an exciting time for the Company.

As many of you are aware, we have a number of significant and potentially transformational events ahead of us this quarter and

over the next six months. Most notably, top-line final results are imminent from two pivotal Phase 3 clinical trials:

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 actively pursue

additional non-dilutive funding to support our rare disease pipeline.

Corporate Highlights

This past year we strengthened our commercial

and business expertise, both at the Board level and with our senior management team, so that we may begin to position the company

for the potential success of our Phase 3 clinical trials.

In July 2019, we announced the addition

of Ms. Diane Parks to our Board of Directors (access press release here). Ms. Parks is an accomplished businesswoman and

commercial executive with an extensive record of driving profitable growth for large pharmaceutical and biotech companies. With

a successful career spanning more than 30 years, she served as Senior Vice President and Head of US Commercial for Kite Pharma,

Inc. (acquired by Gilead Sciences, Inc. for $11.9B), as Vice President and Head of Global Marketing for Pharmacyclics, Inc. (acquired

by Abbvie, Inc. for $21B), as Vice President of Sales for Amgen Inc., and as Senior Vice President, Specialty Biotherapeutics for

Genentech, Inc. (acquired by Roche Holdings AG for $46.8B). As we look forward to potential product approval, we intend to leverage

Ms. Park's extensive business and commercialization experience in launching novel drug therapies in orphan diseases and areas

of high unmet medical need. We believe her expertise adds significantly to our already diverse and experienced Board of Directors

and management team.

In September 2019, we announced the additions

of Jonathan Guarino, CPA, as Senior Vice President and Chief Financial Officer (access press release here) and Daniel Ring, as

Vice President, Business Development and Strategic Planning (access press release here). Both Jonathan and Dan come with extensive

backgrounds in their respective disciplines, while also having experience working for commercial life science companies.

As we look forward to 2020, we continue

to evaluate with prospective partners a number of strategic alternatives including, but not limited to, merger, acquisition, partnership,

alliance, co-development and/or co-commercialization licensing agreements.

Specialized Biotherapeutics Business Segment

We continue to make good progress in advancing

our two pivotal Phase 3 clinical programs.

We remain encouraged by this

development program as a potential front line treatment where there is currently an unmet medical need. You may recall that this

trial, referred to as the "FLASH" study (Fluorescent Light Activated Synthetic Hypericin),

aims to evaluate the response to SGX301 as a skin directed therapy to treat early stage CTCL. SGX301 has received Orphan Drug designation

as well as Fast Track designation from the United States (US) Food and Drug Administration (FDA). Additionally, SGX301 was granted

Orphan Drug designation from the European Medicines Agency (EMA) and Promising Innovative Medicine (PIM) designation from the Medicines

and Healthcare products Regulatory Agency (MHRA) in the United Kingdom (UK).

Approximately 35 CTCL centers

across the US, representing the major Key Opinion Leaders (KOLs) in this indication, are participating in this pivotal trial, which

enrolled 169 subjects. 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 that the majority of patients

have elected to continue with Cycle 3, the optional open-label portion of the study. We also continue to work closely with patient

advocacy groups, such as the Cutaneous Lymphoma Foundation and the National Organization for Rare Disorders.

The CTCL development program

has received partial funding of approximately $1.5 million over two years from a Small Business Innovative Research (SBIR) grant

awarded by the NIH's National Cancer Institute (NCI).

This 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 median 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.

Dusquetide 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. The Phase 2 data demonstrated a significant

reduction in the duration of oral mucositis, as well as reduced infection rates, as published in 2016 in the Journal of Biotechnology

(available here). Long-term follow-up data from the Phase 2 trial, published in 2017 in Biotechnology Reports (available here),

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 HNC patients as well as PIM designation from the MHRA in the UK.

Approximately 50 oncology centers

in the US and Europe are actively participating in this pivotal, Phase 3 study, which is targeted to enroll 260 subjects with squamous

cell carcinoma of the oral cavity and oropharynx who are scheduled to receive the standard treatment regimen with a minimum total

cumulative radiation dose of 55 Gy fractionated as 2.0-2.2 Gy per day and concomitant cisplatin chemotherapy given as a dose of

80-100 mg/m2 every third week.

The oral mucositis development

program has received partial funding of approximately $1.5 million over two years from an SBIR grant awarded by the NIH's

National Institute of Dental and Craniofacial Research (NIDCR).

Public Health Solutions Business Segment

We 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 successfully identified biomarkers for RiVax testing, as published in the journal Vaccine

in 2018 (available here), 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.

We recently initiated a third Phase 1C

vaccine immunogenicity and safety study in healthy volunteers utilizing RiVax (access press release here). This

study is building upon the safety already demonstrated with the RiVax antigen from the two previous Phase 1 clinical

trials, but will look to test the product formulated with our proprietary heat stabilization technology (ThermoVax ).

In parallel, additional efficacy studies in non-human primates are planned, enabling a larger database of biomarkers for correlation

with human clinical results. 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