of Gedeptin® Adds Orphan Drug Clinical Program for
of Advanced Head and Neck Cancers

Atlanta, GA – (NewMediaWire) – September 28, 2021 – GeoVax Labs, Inc. (Nasdaq: GOVX), a biotechnology company
specializing in developing human vaccines and cancer immunotherapies, today
announced that it has entered into an Assignment and License Agreement (the
“License”) with PNP Therapeutics, Inc. (“PNP”), that grants GeoVax exclusive
rights to develop and commercialize Gedeptin®, a novel patented product
for the treatment of solid tumors.  

The License provides exclusive
worldwide rights to key intellectual property,
including Gedeptin patents, know-how, regulatory filings, clinical
materials, and trademarks.  The patent portfolio covering Gedeptin was
originally licensed from the University of Alabama at Birmingham (UAB) and
Southern Research Institute (SRI) by PNP.  Under the License, GeoVax will
become the successor to PNP under its license agreement with UAB/SRI. Detailed
financial terms of the transaction were not disclosed, but include a
combination of upfront payments, milestone fees, and royalties on net sales.

A cycle of Gedeptin therapy
consists of three intra-tumoral injections of Gedeptin over a two-day
period followed by infusion of a prodrug, fludarabine phosphate, once a day for
three days.  A Phase 1 dose ranging study, evaluating the safety of a
single cycle of Gedeptin therapy, found the therapy to be well tolerated, with
evidence of a reduction in tumor size in patients with solid tumors.

A Phase 1/2 trial, evaluating the
safety and efficacy of repeat cycles of Gedeptin therapy in patients with
recurrent head and neck squamous cell carcinoma (HNSCC), with tumor(s)
accessible for injection and no curable treatment options, is currently
enrolling.  The initial stage of the study is being funded by the FDA
pursuant to its Orphan Products Clinical Trials Grants Program. 
The FDA has also granted Gedeptin orphan drug status for the
intra-tumoral treatment of anatomically accessible oral and pharyngeal cancers,
including cancers of the lip, tongue, gum, floor of mouth, salivary gland and
other oral cavities.

The Gedeptin technology was
developed with funding support from the National Cancer Institute of the
National Institutes of Health.  The License also grants GeoVax the rights
to expand the use of Gedeptin to all human diseases and/or conditions
including, but not limited to, other cancers. 

David Dodd, GeoVax President and
CEO, commented, “The signing of this license agreement is an important and
exciting event for GeoVax and our stockholders, as it adds a clinical program
in immuno-oncology to our pipeline, which is one of the primary focus areas for
our company. The initial stage (10 patients) of the ongoing clinical trial for
Gedeptin is being funded by the FDA pursuant to its Orphan Products Grants
Program, with five patients having been enrolled to date.  Our immediate
objective will be to accelerate patient enrollment to complete this stage, then
expand the trial to additional study sites and at least 25 patients in
total.  Based on PNP’s End-of-Phase-1 meeting with the FDA, we believe
that a successful outcome from the expanded trial may lead to labeling
discussions with the FDA at the end of the study.”

Dodd added, “In addition to the
immediate opportunity resulting from the existing clinical program, the license
to the Gedeptin technology opens additional opportunities to potentially
develop novel therapies for other indications.  We also feel that
potential synergies exist between the Gedeptin technology and our GV-MVA-VLP™
platform related to immuno-oncology, providing further expanded opportunities
for developing novel cancer immunotherapies that may benefit cancer patients
across multiple cancers.  As we continue to advance our programs such as
MVA-VLP-MUC1, we will also evaluate synergistic opportunities between the two
technology platforms.” 

In conclusion, Dodd commented,
“Approximately one year ago, we achieved a critical strategic watershed with
the successful recapitalization, financing and listing of GeoVax on the Nasdaq
stock market.  Since then, we have further strengthened the Company
resources and status, including our ability to finance the Gedeptin
transaction, including expansion and acceleration of the clinical trial using
our current cash reserves.  We have progressed our two core product
development areas related to SARS-CoV-2 vaccines and immuno-oncology. 
Today’s announcement accelerates our progress within immuno-oncology, providing
a pivotal clinical-stage status via the Gedeptin program.  We similarly remain
focused on accelerating progress related to our SARS-CoV-2 vaccine and look
forward to providing further updates soon.” 

Conference Call

Management will host a conference
call at 4:30 p.m. ET on Wednesday, September 29, 2021 to review the transaction
and discuss the Gedeptin technology. Following management’s formal remarks,
there will be a question-and-answer session.  

Participants are asked to
pre-register for the call via the following link:

The conference call will be
available through a live webcast found here:

A webcast replay of the call will
be available via the same link as the live webcast approximately one hour after
the end of the call through December 28, 2021.  A telephonic replay of the
call can be accessed by calling 1-877-344-7529 (domestic) or 1-412-317-0088
(international) and using access code 10160579.  The telephonic replay
will be available until October 13, 2021.

About the Gedeptin® Technology

Many common cancers (including
prostate, breast, colon, lung, brain, melanoma, pancreas, ovarian, kidney)
become untreatable despite the best medical intervention and the highest
standard of care and are eventually fatal. Chemotherapeutic agents may be able
to destroy these tumors, but many are much too toxic to administer systemically
to already debilitated cancer patients. Most conventional anti-cancer drugs in
use today derive their anti-tumor specificity from the ability to kill rapidly
dividing cells. These drugs are suitable for systemic administration
specifically because they are most toxic to cells that are dividing. However,
many tumors such as head and neck squamous cell carcinoma (HNSCC) are resistant
to treatment because they have a very low growth fraction (i.e., a relatively
small percentage of tumor cells dividing at any particular point in time).
Compounds toxic to non-proliferating cells generally are not used in the
treatment of cancer, because most of the cells in a patient are not
proliferating and such compounds have no selectivity when administered

Among the various gene therapy
strategies for cancer treatment, GDEPT (Gene-Directed Enzyme Prodrug Therapy)
has shown promise. In GDEPT a vector is used to selectively transduce tumor
cells with a nonhuman gene, which expresses an enzyme that can convert a
nontoxic prodrug into a very toxic antitumor compound.  A prodrug is a
pharmaceutical compound that remains inactive in its biochemical form until it
reaches its target site, such as an organ or tissue, and then undergoes an
immediate metabolic breakdown; it then releases the molecular compounds of the
parent drug, or active ingredients, at the point of delivery. Because the
nonhuman gene is only expressed in tumor tissue, the nontoxic prodrug is only activated
in tumor tissue. Therefore, unlike conventional chemotherapy, GDEPT should
result in selective killing of tumor cells with little or no systemic toxicity.

GDEPT strategies that produce
potent cytotoxic agents (active against nonproliferating and proliferating
tumor cells) and that have high bystander activity could have dramatic effects
on the treatment of solid tumors. A bystander effect typically refers to the
death, altered growth or damage of cells that have not directly received
chemotherapy or irradiation. Earlier GDEPT approaches have had limited efficacy
specifically because of poor bystander activity and inability to destroy
non-proliferating tumor cells. 

Gedeptin potentially overcomes
previous GDEPT limitations and may serve as a robust platform for development
in multiple indications. Gedeptin consists of a non-replicating adenoviral
vector expressing an optimized E. coli purine nucleoside phosphorylase (E. coli
PNP) that is injected intra-tumorally, and then followed by intravenous or intra-tumoral
administration of a prodrug.  

Among the prodrugs that have been
evaluated for use with Gedeptin, fludarabine phosphate (Fludara®) is of
particular interest because (i) it is currently approved by the FDA for use in
humans and (ii) it has demonstrated excellent in vivo antitumor activity in
murine models when only 2-3% of tumor cells express E. coli PNP. Fludarabine is
currently approved by the FDA to treat chronic lymphocytic leukemia, but has
not been shown to be effective against other solid tumors.  But when
fludarabine is administered following Gedeptin, the combination exploits
the selective expression of the E. coli PNP gene in tumor cells to utilize
fludarabine phosphate as a prodrug, resulting in the localized production of fluoroadenine
(F-Ade), a potent cytotoxic compound with pronounced antitumor activity.

Ongoing Phase 1/2 Clinical
 – Currently, Gedeptin is in a Phase 1/2 clinical
trial, being conducted at Stanford University in collaboration with Emory
University. The trial design involves repeat administration using Gedeptin
followed by systemic fludarabine, as a way to gain additional information prior
to expansion towards a larger patient trial. The initial stage of the study (10
patients) is being funded by the FDA pursuant to its Orphan Products
Grants Program.  Five patients have been enrolled to date.

Orphan Drug Status – The
FDA has granted orphan drug status to Gedeptin, for the intra-tumoral treatment
of anatomically accessible oral and pharyngeal cancers, including cancers of
the lip, tongue, gum, floor of mouth, salivary gland and other oral cavities.
The orphan drug designation is awarded to drugs designed to treat a rare
disease or condition that affects fewer than 200,000 people in the U.S., and it
is applied specifically to novel therapeutics that could represent a major
improvement in treatment. Orphan drug status provides regulatory incentives,
reduced fees, and a more rapid review by the FDA, and stipulates that competing
therapies can be blocked from the market for up to seven years. Additionally,
this status qualifies the drug sponsor for various development incentives,
including tax credits for qualified clinical testing.

About GeoVax

GeoVax Labs, Inc. is a
clinical-stage biotechnology company developing human vaccines against
infectious diseases and cancer using a novel patented Modified Vaccinia
Ankara-Virus Like Particle (MVA-VLP) based vaccine platform. On this platform,
MVA, a large virus capable of carrying several vaccine antigens, expresses
proteins that assemble into VLP immunogens in the person receiving the vaccine.
The production of VLPs in the person being vaccinated can mimic virus
production in a natural infection, stimulating both the humoral and cellular
arms of the immune system to recognize, prevent, and control the target
infection. The MVA-VLP derived vaccines can elicit durable immune responses in
the host similar to a live-attenuated virus, while providing the safety
characteristics of a replication-defective vector. 

GeoVax’s current development
programs are focused on preventive vaccines against COVID-19, HIV, Zika Virus,
hemorrhagic fever viruses (Ebola, Sudan, Marburg, and Lassa), and malaria, as
well as therapeutic vaccines against multiple cancers. The Company has designed
a preventive HIV vaccine candidate to fight against the subtype of HIV
prevalent in the commercial markets of the Americas, Western Europe, Japan, and
Australia; human clinical trials for this program are managed by the HIV
Vaccine Trials Network (HVTN) with the support of the National Institutes of
Health (NIH). GeoVax’s HIV vaccine is also part of a collaborative effort
toward a functional cure for HIV.

Forward-Looking Statements

This release contains
forward-looking statements regarding GeoVax’s business plans. The words
“believe,” “look forward to,” “may,” “estimate,” “continue,” “anticipate,”
“intend,” “should,” “plan,” “could,” “target,” “potential,” “is likely,”
“will,” “expect” and similar expressions, as they relate to us, are intended to
identify forward-looking statements. We have based these forward-looking
statements largely on our current expectations and projections about future
events and financial trends that we believe may affect our financial condition,
results of operations, business strategy and financial needs. Actual results
may differ materially from those included in these statements due to a variety
of factors, including whether: GeoVax is able to
acceptable results from the current phase 1/2 clinical trial
involving Gedeptin
 or additional tests of  its preventive
vaccine, GeoVax’s immuno-oncology products and preventative vaccines can
provoke the desired responses, and those products or vaccines can be used
effectively, GeoVax’s viral vector technology adequately amplifies immune responses
to cancer antigens, GeoVax can develop and manufacture its immuno-oncology
products and preventative vaccines with the desired characteristics in a timely
manner, GeoVax’s immuno-oncology products and preventative vaccines will be
safe for human use, GeoVax’s vaccines will effectively prevent targeted
infections in humans, GeoVax’s immuno-oncology products and preventative
vaccines will receive regulatory approvals necessary to be licensed and
marketed, GeoVax raises required capital to complete development, there is
development of competitive products that may be more effective or easier to use
than GeoVax’s products, GeoVax will be able to enter into favorable
manufacturing and distribution agreements, and other factors, over which GeoVax
has no control. 

Further information on our risk
factors is contained in our registration statement on Form S-1 and the periodic
reports on Form 10-Q and Form 10-K that we have filed and will file with the
SEC. Any forward-looking statement made by us herein speaks only as of the date
on which it is made. Factors or events that could cause our actual results to
differ may emerge from time to time, and it is not possible for us to predict
all of them. We undertake no obligation to publicly update any forward-looking
statement, whether as a result of new information, future developments or
otherwise, except as may be required by U.S. federal securities law. 

GeoVax Labs, Inc.