GeoVax's Multi-Antigen COVID-19 Vaccine Shows Promising Results in Immunocompromised Patients

GeoVax Labs (搜索)搜索该公司, Inc. (Nasdaq: GOVX) has reported promising clinical results for its multi-antigen SARS-CoV-2 (搜索)搜索该疾病 vaccine candidate, GEO-CM04S1查看药品详情, demonstrating durable immune responses in both healthy volunteers and immunocompromised patients.

The clinical-stage biotechnology company presented new data at the 25th Annual World Vaccine Congress in Washington, D.C., highlighting the vaccine's performance across several Phase 1 and 2 clinical trials. The presentation, delivered by Don J. Diamond, Ph.D., showcased results from studies involving healthy adults as well as vulnerable populations including stem cell transplant recipients and patients with chronic lymphocytic leukemia (搜索)搜索该疾病 (CLL).

Dual-Antigen Approach Shows Broad Immunity

GEO-CM04S1查看药品详情 is based on the synthetic Modified Vaccinia Ankara (MVA) vector platform and uniquely expresses both the Spike (搜索)搜索该靶点 (S) and Nucleocapsid (搜索)搜索该靶点 (N) antigens of SARS-CoV-2 (搜索)搜索该疾病. This dual-antigen approach appears to generate broader and more durable immune responses compared to single-antigen vaccines.

In a Phase 1 trial with healthy adults, 100% of participants (34/34) produced Spike (搜索)搜索该靶点 IgG antibodies, while 94% (32/34) developed Nucleocapsid (搜索)搜索该靶点 IgG antibodies. Additionally, 98% (48/49) demonstrated T cell responses to either antigen following vaccination, with no serious safety concerns reported across varying dose levels.

Superior Performance in Immunocompromised Patients

Perhaps most notably, GEO-CM04S1查看药品详情 showed particularly strong results in immunocompromised populations—groups that have historically responded poorly to existing mRNA vaccines.

In stem cell transplant recipients, the vaccine induced antibody titers and T cell responses that exceeded those observed in healthy volunteers. More dramatically, a randomized Phase 2 trial comparing GEO-CM04S1查看药品详情 to the Pfizer-BioNTech (搜索)搜索该词条 (Comirnaty查看药品详情®) vaccine in CLL patients revealed significantly higher T cell response rates with GEO-CM04S1.

"At Day 56 of the study, 6 of 15 patients in the GEO-CM04S1查看药品详情 arm achieved 3-fold increases in Spike (搜索)搜索该靶点 or Nucleocapsid (搜索)搜索该靶点-specific T cells versus only 2 of 14 in the Comirnaty查看药品详情 arm," Diamond reported. The Data and Safety Monitoring Board subsequently recommended halting enrollment in the Pfizer arm due to underperformance, while continuing enrollment in the GEO-CM04S1 arm.

Effective Booster at Lower Doses

The vaccine also demonstrated strong performance as a booster in healthy volunteers previously vaccinated with mRNA or protein-based COVID-19 (搜索)搜索该疾病 vaccines. In this Phase 2 booster trial, participants showed significant increases in Spike (搜索)搜索该靶点, RBD, and Nucleocapsid (搜索)搜索该靶点 IgG antibody responses, as well as neutralization titers against multiple COVID-19 variants, including XBB.1.5.

Importantly, these robust responses were achieved at both higher and lower dose levels, with no meaningful differences between them—suggesting potential dose-sparing capabilities.

Potential Dual Protection Against COVID-19 and Mpox

In a separate presentation at the AAI Annual Meeting 2025, researchers highlighted GEO-CM04S1查看药品详情's potential to provide protection against both COVID-19 (搜索)搜索该疾病 and Mpox (搜索)搜索该疾病. The presentation, titled "Immunogenicity of Synthetic MVA-based Vaccine COH04S1 Against SARS-CoV-2 (搜索)搜索该疾病 in Post-HCT/CAR-T Patients and Its Cross-Protective Potential Against Mpox," revealed that sera from COH04S1-vaccinated individuals demonstrated cross-reactive immunity against Mpox virus.

These immune responses were found comparable to those in humans receiving the currently licensed smallpox/Mpox (搜索)搜索该疾病 vaccine (Jynneos查看药品详情). Furthermore, sera from vaccinated individuals protected against lung infection in susceptible mice challenged with Mpox virus.

"These findings underscore the differentiated potential of GEO-CM04S1查看药品详情 to serve dual roles as both a next-generation multi-antigen COVID-19 (搜索)搜索该疾病 vaccine and a cross-protective agent against Mpox (搜索)搜索该疾病," said Kelly T. McKee, Jr., M.D., Chief Medical Officer of GeoVax. "The ability to stimulate strong, broad, and durable immunity, particularly in immunocompromised individuals, represents a meaningful advancement over current vaccines."

Ongoing Clinical Development

GEO-CM04S1查看药品详情 is currently being evaluated in three Phase 2 clinical trials:

1. As a primary vaccine for immunocompromised patients such as those undergoing stem cell transplantation or CAR-T therapy, in a randomized comparison to mRNA vaccines

2. As a booster vaccine for patients with chronic lymphocytic leukemia (搜索)搜索该疾病 (CLL), in a randomized comparison to an mRNA vaccine

3. As a booster for healthy adults previously vaccinated with mRNA COVID-19 (搜索)搜索该疾病 vaccines

"The clinical performance of GEO-CM04S1查看药品详情 across diverse and high-risk populations supports our mission to deliver broad and lasting protection through next-generation vaccines," said David A. Dodd, Chairman, President, and CEO of GeoVax. "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."

Market Implications

The positive clinical results come at a time when public health officials are emphasizing the need for more effective vaccines for vulnerable populations. Immunocompromised patients, including those with blood cancers and transplant recipients, remain at higher risk for severe COVID-19 (搜索)搜索该疾病 outcomes despite current vaccination options.

If GEO-CM04S1查看药品详情 continues to demonstrate superior performance in these populations through later-stage trials, it could potentially fill an important gap in the current vaccine landscape. The added potential for cross-protection against Mpox (搜索)搜索该疾病 further enhances its public health value, particularly in regions where Mpox is endemic.

GeoVax holds worldwide rights for its technologies and products, positioning the company to potentially capitalize on these developments as the vaccine advances through clinical trials.