EQS-News: GeoVax Highlights Strong Clinical Results Following Presentation of Multi-Antigen COVID-19 Vaccine at the 25th Annual World Vaccine Congress

GEO-CM04S1 Demonstrates Durable T Cell and Antibody Responses in Healthy and Immunocompromised Populations

ATLANTA, GA - April 24, 2025 (NEWMEDIAWIRE) - GeoVax Labs, Inc. (Nasdaq: GOVX), a clinical-stage biotechnology company developing vaccines and immunotherapies for infectious diseases and cancer, today recapped the successful presentation of new clinical data on its multi-antigen SARS-CoV-2 vaccine candidate, GEO-CM04S1, delivered at the 25th Annual World Vaccine Congress in Washington, D.C.

The presentation, titled “Phase 2b Study Results That Evaluated and Compared GeoVax’s Multi-Antigen Vaccine Candidate (GEO-CM04S1) to an Approved Vaccine Against COVID-19,” was given by Don J. Diamond, Ph.D. on April 24, 2025. It highlighted results across several Phase 1 and 2 clinical trials, including studies involving healthy volunteers as well as immunocompromised patients such as stem cell transplant recipients and those with chronic lymphocytic leukemia (CLL).

GEO-CM04S1, based on the synthetic Modified Vaccinia Ankara (MVA) vector platform, uniquely expresses both the Spike (S) and Nucleocapsid (N) antigens of SARS-CoV-2 - resulting in broad and durable immune responses even in populations that have historically responded poorly to mRNA vaccines.

Key Highlights from the Clinical Data Presented

Robust Immune Response in Healthy Adults

• In a Phase 1 trial, 100% of participants (34/34) seroconverted (i.e., produced antibodies) for Spike IgG, and 94% (32/34) for Nucleocapsid IgG.
• 98% (48/49) demonstrated a T cell response to either antigen following vaccination.
• No serious safety concerns were reported across varying dose levels.

Comparable Immunogenicity at Lower Doses (Phase 2 Booster Trial)

• Healthy volunteers who had previously received mRNA or protein-based COVID-19 vaccines were boosted with GEO-CM04S1 at two dose levels (10⁷ vs 10⁸ pfu).
• Spike, RBD, and Nucleocapsid IgG antibody responses, as well as neutralization titers against multiple COVID-19 variants (including XBB.1.5), increased significantly at both dose levels with no meaningful differences between them.
• T cell responses increased significantly post-vaccination, regardless of baseline immunity.

Superior Performance in Immunocompromised Populations

• In stem cell transplant recipients, GEO-CM04S1 induced ELISA antibody titers and T cell responses that exceeded those observed in healthy volunteers.
• In a randomized Phase 2 trial comparing GEO-CM04S1 to the Pfizer-BioNTech (Comirnaty®) vaccine in patients with Chronic Lymphocytic Leukemia, GEO-CM04S1 demonstrated a significantly higher T cell response rate.
  • At Day 56 of the study: 6 of 15 patients in the GEO-CM04S1 arm achieved ≥3-fold increases in Spike or Nucleocapsid-specific T cells versus 2 of 14 in the Comirnaty arm.
  • The Data and Safety Monitoring Board (DSMB) recommended halting enrollment in the Pfizer arm due to underperformance, while continuing enrollment of the GEO-CM04S1 arm.

“We were pleased to share these promising results with global leaders in vaccinology,” said Don J. Diamond, Ph.D. “The data underscore the value of our dual-antigen approach, particularly for patients underserved by existing single-antigen vaccines. GEO-CM04S1 not only drives strong antibody and T cell immunity in healthy adults, but also in the immunocompromised - a population historically underserved by single-antigen mRNA vaccines.”

David A. Dodd, Chairman, President, and CEO of GeoVax, added: “The clinical performance of GEO-CM04S1 across diverse and high-risk populations supports our mission to deliver broad and lasting protection through next-generation vaccines. Our data continues to demonstrate strong, durable immune responses in both healthy and immunocompromised populations - a critical feature of our vaccine for public health preparedness. As we continue to advance this program, these results reinforce our confidence in the MVA platform as a foundation for addressing future public health threats.”

About GEO-CM04S1

GEO-CM04S1 is a next-generation COVID-19 vaccine based on the Modified Vaccinia Ankara (MVA) vector originally developed at City of Hope. Its multi-antigen design expresses both Spike and Nucleocapsid proteins of SARS-CoV-2, promoting broad, cross-reactive immunity. The vaccine is being evaluated in three ongoing Phase 2 clinical trials.

 About GeoVax

GeoVax Labs, Inc. is a clinical-stage biotechnology company developing novel vaccines against infectious diseases and therapies for solid tumor cancers. The Company’s lead clinical program is GEO-CM04S1, a next-generation COVID-19 vaccine currently in three Phase 2 clinical trials, being evaluated as (1) a primary vaccine for immunocompromised patients such as those suffering from hematologic cancers and other patient populations for whom the current authorized COVID-19 vaccines are insufficient, (2) a booster vaccine in patients with chronic lymphocytic leukemia (CLL) and (3) a more robust, durable COVID-19 booster among healthy patients who previously received the mRNA vaccines. In oncology the lead clinical program is evaluating a novel oncolytic solid tumor gene-directed therapy, Gedeptin®, having recently completed a multicenter Phase 1/2 clinical trial for advanced head and neck cancers. The Company is also developing GEO-MVA, a vaccine targeting Mpox and smallpox. GeoVax has a strong IP portfolio in support of its technologies and product candidates, holding worldwide rights for its technologies and products. For more information about the current status of our clinical trials and other updates, visit our website: 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                          

Investor Relations Contact:
geovax@precisionaq.com
212-698-8696

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