GeoVax Labs, Inc. announced publication of interim Phase 2 clinical data showing its next-generation COVID-19 vaccine, GEO-CM04S1, generated significantly stronger and more durable SARS-CoV-2-specific T-cell responses than BNT162b2 in patients with chronic lymphocytic leukemia. The findings, published in the British Journal of Haematology, highlight the vaccine's potential to address protection gaps for immunocompromised populations who respond poorly to first-generation vaccines.
The trial's Data and Safety Monitoring Board discontinued the randomized comparator arm after the mRNA vaccine failed to meet the primary immunogenicity endpoint, with enrollment now proceeding exclusively with GEO-CM04S1. This decision underscores the clinical relevance of GeoVax's vaccine for patients with compromised immunity, a population exceeding 40 million in the U.S. and 400 million globally.
In the Phase 2 study (NCT05672355), 40% of GEO-CM04S1 recipients met the primary endpoint of a three-fold or greater rise in antigen-specific IFN-γ-secreting T cells at Day 56, compared to 14.3% for BNT162b2. The vaccine demonstrated approximately 10-fold higher nucleocapsid-specific CD4 T-cell activation and maintained responses through Day 180, while generating sustained N-IgG antibodies and correlation between N-specific antibodies and T-cell activation.
Kelly T. McKee, MD, MPH, Chief Medical Officer, stated the results demonstrate GEO-CM04S1's ability to address immune limitations in CLL patients by inducing strong, durable T-cell responses to both spike and nucleocapsid proteins. The dual-antigen, MVA-based platform promotes robust cellular immunity less impacted by immune dysfunction and viral variation, representing a purpose-built solution for high-risk patients according to Chairman & CEO David Dodd.
The medical significance extends beyond CLL patients to broader immunocompromised populations, including CAR-T and stem-cell transplant recipients who typically respond poorly to current vaccines. With these segments representing a potential $30 billion annual commercial market, the peer-reviewed publication strengthens GeoVax's regulatory and partnering strategy as the company advances toward potential commercialization. For more information about clinical trials and updates, visit https://www.geovax.com.
