GeoVax Highlights Gedeptin® Tumor-Priming Strategy as Immuno-Oncology Enters New Phase

FDA Approval of Replimune's Intratumoral Therapy in Combination With Checkpoint Inhibition Reinforces Growing Momentum Behind Tumor-Directed Approaches Designed to Enhance Anti-Tumor Immune Response

ATLANTA, GA - August 11, 2026 (NEWMEDIAWIRE) - GeoVax Labs, Inc. (Nasdaq: GOVX), a clinical-stage biotechnology company developing vaccines and immunotherapies for infectious diseases and solid tumors, today highlighted the recent U.S. Food and Drug Administration (FDA) accelerated approval of Replimune Group, Inc.’s TUDRIQEV™ (formerly RP1) in combination with nivolumab as an important milestone in the evolution of intratumoral cancer immunotherapy.

The FDA approved TUDRIQEV in combination with nivolumab for adults with unresectable advanced cutaneous melanoma whose disease has progressed following prior anti-PD-1 therapy. The approval followed a favorable FDA Advisory Committee recommendation and represents an important regulatory milestone for localized tumor-directed therapies used in combination with immune checkpoint inhibitors (ICIs).

While TUDRIQEV and GeoVax’s investigational solid tumor therapy Gedeptin® employ different mechanisms of action to achieve tumor cell killing, GeoVax believes the approval reinforces a broader therapeutic paradigm: local destruction of tumor masses may modify the tumor microenvironment and potentially enhance immune responses both within directly treated tumors and at distant tumor sites.

“This approval represents an important milestone that extends well beyond any individual product,” said David A. Dodd, Chairman and Chief Executive Officer of GeoVax. “It provides clinical and regulatory precedent for locally administered therapies used in combination with checkpoint inhibition. We believe this represents an increasingly important direction for cancer immunotherapy.”

Overcoming the “Cold Tumor” Barrier

Earlier this year, Mr. Dodd outlined this emerging concept in an Onco’Zine commentary entitled The Cold Tumor Barrier: Why Promising Oncology Therapies Fail In Vivo – and What It Will Take to Overcome It (Onco'Zine Cold Tumor Barrier). The article describes immunologically “cold” tumors - characterized by limited T-cell infiltration, poor antigen presentation and an immunosuppressive tumor microenvironment - as a fundamental barrier limiting the effectiveness of checkpoint inhibitors and other immunotherapies.

The article argues that durable advances in immuno-oncology may increasingly depend upon therapies capable of priming the tumor microenvironment and converting immunologically “cold” tumors into immune-responsive “hot” tumors, thereby creating the biological conditions necessary for checkpoint inhibitors to function more effectively.

GeoVax believes Gedeptin® represents a differentiated approach to this emerging therapeutic paradigm. Unlike replication-dependent oncolytic viruses, Gedeptin utilizes a gene-directed enzyme prodrug therapy (GDEPT) approach in which a replication-deficient adenoviral vector delivers a bacterial enzyme, purine nucleoside phosphorylase (PNP), directly into tumor tissue. Following administration of fludarabine phosphate, the enzyme converts the inactive prodrug into a potent cytotoxic metabolite within the tumor microenvironment, producing localized tumor destruction and a demonstrated preclinical bystander effect extending beyond directly transduced tumor cells, while promoting anti-tumor immune responses. Importantly, GeoVax believes Gedeptin’s potential therapeutic value extends beyond localized cytotoxicity.

Published Evidence Supporting Tumor Priming and Checkpoint Inhibitor Synergy

In recently published research in JCI Insight, Gedeptin combined with anti-PD-1 therapy in an immunocompetent preclinical model demonstrated enhanced anti-tumor immune responses, increased CD8+ T-cell infiltration, systemic anti-tumor activity and improved therapeutic outcomes compared with checkpoint inhibition alone.

These findings provide scientific support for the thesis that Gedeptin may function as a tumor-priming immunotherapy, using localized tumor destruction and immune activation to help transform immunologically resistant tumors into tumors more responsive to checkpoint inhibition.

“The objective is not simply to destroy tumor cells locally,” said Kelly McKee, M.D., Chief Medical Officer of GeoVax. “The greater opportunity is to initiate the immune recognition necessary for checkpoint inhibitors to work more effectively. These findings demonstrate Gedeptin’s potential to combine extensive localized tumor killing with immune activation, creating a more favorable tumor microenvironment for checkpoint inhibition.”

A Converging Immuno-Oncology Strategy

GeoVax believes several recent developments now point toward a converging therapeutic strategy within immuno-oncology:

• Regulatory precedent: FDA accelerated approval of TUDRIQEV plus nivolumab establishes an approved intratumoral immunotherapy/checkpoint inhibitor combination for patients with advanced melanoma following anti-PD-1 therapy.
• Scientific evidence: The JCI Insight publication provides preclinical evidence that Gedeptin can enhance anti-tumor immune activity and checkpoint inhibitor responsiveness.
• Tumor-priming strategy: Growing scientific understanding of the “cold tumor” barrier supports approaches designed to modify the tumor microenvironment before or in conjunction with checkpoint inhibition.

Gedeptin is mechanistically distinct from TUDRIQEV. Rather than relying on viral replication and oncolysis, Gedeptin is designed to generate potent cytotoxic activity directly within the tumor through enzyme-directed prodrug activation, with a substantial bystander effect capable of extending tumor killing beyond cells directly reached by the vector.

GeoVax believes this differentiated mechanism has the potential to position Gedeptin as a tumor-priming immunotherapy designed to enhance the effectiveness of established immunotherapies, rather than simply as another intratumoral therapy. The Company is continuing preparations for the next phase of Gedeptin’s clinical development in combination with pembrolizumab for patients with head and neck squamous cell carcinoma. The planned study is expected to evaluate clinical activity together with biomarkers of immune activation, tumor microenvironment modulation and pathological tumor response.

“The FDA approval of an intratumoral therapy combined with checkpoint inhibition reinforces a therapeutic direction that we believe has significant potential,” concluded Mr. Dodd. “Our objective with Gedeptin is to address one of the fundamental barriers limiting immunotherapy - the inability of immunologically cold tumors to generate an effective anti-tumor immune response. Our published science provides an important foundation for that strategy, and we believe Gedeptin’s differentiated mechanism warrants continued clinical development.”

About Gedeptin®

Gedeptin® is GeoVax’s investigational gene-directed enzyme prodrug therapy (GDEPT) for the treatment of solid tumors. The therapy utilizes a replication-deficient adenoviral vector to deliver the bacterial enzyme purine nucleoside phosphorylase (PNP) directly into tumors. Following administration of fludarabine phosphate, the PNP enzyme converts the inactive prodrug into a potent cytotoxic metabolite within the tumor microenvironment, producing localized tumor cell death while promoting anti-tumor immune responses. Gedeptin is being developed in combination with immune checkpoint inhibitors for the treatment of solid tumors.

About GeoVax

GeoVax Labs, Inc. is a clinical-stage biotechnology company focused on the development of vaccines and immunotherapies addressing high-consequence infectious diseases and solid tumor cancers. GeoVax’s priority program is GEO-MVA, a Modified Vaccinia Ankara (MVA)–based vaccine targeting mpox and smallpox. The program is advancing under an expedited regulatory pathway, with plans to initiate a pivotal Phase 3 clinical trial in the second half of 2026, to address critical global needs for expanded orthopoxvirus vaccine supply and biodefense preparedness. In oncology, GeoVax is developing Gedeptin®, a gene-directed enzyme prodrug therapy (GDEPT) designed to enhance immune checkpoint inhibitor activity. Gedeptin has completed a multicenter Phase 1/2 clinical trial in advanced head and neck cancer and is being advanced into combination strategies, including planned neoadjuvant and first-line settings. GeoVax maintains a global intellectual property portfolio supporting its infectious disease and oncology programs and continues to evaluate strategic partnerships and funding opportunities aligned with its development priorities. For more information, visit www.geovax.com.

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 obtain acceptable results from ongoing or future clinical trials of its investigational products, 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 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 law.

Company Contact:
info@geovax.com
678-384-7220

Media Contact:
Jessica Starman
media@geovax.com

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