GeoVax's GEO-CM04S1 Vaccine Shows T Cell Responses vs. mRNA Vaccine In Phase 2 Trial For CLL Patients, Meeting Key Immunogenicity Endpoints And Driving Continued Enrollment, At 2025 EHA Congress Presentation

https://geovax.com/investors/press-releases/geovax-highlights-positive-immune-response-results-from-geo-cm04s1-in-cll-patients-at-the-european-hematology-association-2025-meeting

 

GEO-CM04S1 Demonstrates Superior T Cell Responses Compared to mRNA Vaccine in Phase 2 Trial Among Immunocompromised Patients

ATLANTA, GA, June 17, 2025 – GeoVax Labs, Inc. (NASDAQ:GOVX), a clinical-stage biotechnology company developing multi-antigen vaccines and immunotherapies for infectious diseases and cancer, today highlighted new clinical data presented at the 2025 European Hematology Association (EHA) Hybrid Congress which took place June 12-15 in Milan, Italy.

The data were featured in a poster presentation by Alexey V. Danilov, M.D., Ph.D., Associate Director of the Toni Stephenson Lymphoma Center and Professor in the Department of Hematology and Hematopoietic Cell Transplantation at City of Hope Comprehensive Cancer Center in Duarte, California. The poster titled "MVA-Based GEO-CM04S1 Vaccine Results in Improved Cellular Immune Response in Patients with Chronic Lymphocytic Leukemia (CLL) Compared with mRNA-Based Vaccine: Initial Results of a Phase II Randomized Study", detailed findings from an ongoing randomized Phase 2 clinical trial (NCT05672355), and highlighted interim results showing superior cellular immune responses induced by GEO-CM04S1 compared to those induced by an authorized mRNA-based COVID-19 vaccine in CLL patients—a population known to exhibit suboptimal protective responses to COVID-19 and other vaccines due to immune dysfunction.

Key Findings from the Study

• GEO-CM04S1 demonstrated significantly enhanced T cell responses—specifically IFN-γ secretion and activation-induced markers (AIM+)—compared to a matched cohort receiving an authorized mRNA vaccine.
• While both vaccines stimulated humoral immune responses, only GEO-CM04S1 elicited statistically significant SARS-CoV-2 Nucleocapsid (N)-specific IgG and T cell responses.
• The mRNA vaccine failed to meet the pre-defined primary immunogenicity endpoint; as a result, further enrollment is now restricted to the GEO-CM04S1 arm only.
• Both vaccines were well-tolerated, with no grade ≥3 adverse events reported.