Next-Generation Multi-Antigen COVID-19 Vaccine Demonstrates Strong Immune Responses in High-Need Patient Populations

ATLANTA, GA - September 12, 2025 (NEWMEDIAWIRE) - GeoVax Labs, Inc. (Nasdaq: GOVX), a clinical-stage biotechnology company developing multi-antigen vaccines and immunotherapies for infectious diseases and cancer, today discussed positive interim clinical results for its lead COVID-19 vaccine candidate, GEO-CM04S1, presented at the 6th ESCMID Conference on Vaccines in Lisbon, Portugal.

The data, presented by GeoVax Chief Medical Officer Kelly T. McKee, Jr., MD, MPH, highlighted encouraging immune response findings from ongoing Phase 2 clinical studies in immunocompromised patients with blood cancers and chronic lymphocytic leukemia (CLL).

Key Takeaways

• No Serious Adverse Events: No serious adverse events attributed to GEO-CM04S1, reinforcing confidence in the platform.
• Robust Immunity: Potent, durable T-cell and cross-variant antibody responses observed in blood cancer and post-transplant patients - immune responses that exceed those of standard-of-care vaccines.
• Competitive Differentiation: In the CLL trial interim analysis, GEO-CM04S1 met its primary endpoint, while the comparator mRNA vaccine did not, prompting continuation solely in the GEO-CM04S1 arm.
• Pipeline Advancement: An updated construct incorporating the Omicron KP.2 Spike gene is slated for a 2026 trial, positioning GeoVax at the forefront of next-generation, multi-antigen COVID-19 vaccines.

“These results underscore the value and competitive advantage of our multi-antigen MVA vaccine platform,” said David Dodd, Chairman & CEO of GeoVax. “We believe GEO-CM04S1 can address urgent unmet needs among immunocompromised patients, a market segment underserved by first-generation COVID-19 vaccines. The progress we are making reinforces GeoVax’s potential to deliver differentiated, high-value vaccine solutions.”

About GEO-CM04S1

GEO-CM04S1 is a next-generation COVID-19 vaccine based on a Modified Vaccinia Ankara (MVA) vector. Unlike single-antigen vaccines, GEO-CM04S1 expresses both the Spike (S) and Nucleocapsid (N) proteins of SARS-CoV-2, designed to stimulate robust humoral and cellular immunity. Clinical studies to date demonstrate durable immune responses and cross-variant protection, including activity against Omicron subvariants such as XBB.1.5. GEO-CM04S1 is currently in three Phase 2 clinical trials: (1) as a primary vaccine for immunocompromised patients with blood cancers or post-transplant status, (2) as a booster in patients with chronic lymphocytic leukemia (CLL), and (3) as a booster in healthy adults previously vaccinated with mRNA vaccines. An updated construct incorporating the Omicron KP.2 Spike gene is expected to begin clinical testing in 2026.

Strategic Opportunity

COVID-19 continues to pose a significant threat to immunocompromised patients, representing a multi-billion-dollar global market where first-generation vaccines have limited value. GEO-CM04S1’s multi-antigen approach positions GeoVax to lead in this underserved space, while providing platform validation for broader applications across infectious diseases.

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. GeoVax is also developing a vaccine targeting Mpox and smallpox and, based on recent EMA regulatory guidance, anticipates progressing directly to a Phase 3 clinical evaluation, omitting Phase 1 and Phase 2 trials. 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

Media Contact:
Jessica Starman
media@geovax.com