GeoVax Announces Positive Interim Data Review for Phase 2 Clinical Trial of COVID-19 Vaccine Booster in Patients With Chronic Lymphocytic Leukemia

GeoVax Labs, Inc. recently announced the completion of an interim data review by the Data Safety Monitoring Board (DSMB) for the ongoing Phase 2 clinical trial of GEO-CM04S1, GeoVax’s dual-antigen next-generation COVID-19 vaccine, as a booster vaccine for patients with chronic lymphocytic leukemia (CLL).

Based on the interim analysis of immune responses from the patients enrolled to date, the DSMB determined that, while the mRNA control arm of the study failed to meet the predetermined primary endpoint, the study should continue enrollment of the experimental arm utilizing GeoVax’s Next-Generation GEO-CM04S1 vaccine. The Phase 2 trial is an investigator-initiated clinical study (ClinicalTrials.gov Identifier: NCT05672355) being conducted at City of Hope National Medical Center. The study is examining the use of two injections of GEO-CM04S1, three months apart, to assess immune responses in CLL patients, with an mRNA vaccine as the control arm. Thus far, participants have been randomized 1:1 to receive two boosters with either the GEO-CM04S1 or the mRNA control vaccine.

“This is very exciting news,” said David Dodd, GeoVax President and CEO. “The outcome of the DSMB interim review appears to support our view of GEO-CM04S1 as a potentially superior COVID-19 vaccine booster within the CLL patient population. Within the CLL and other immune-compromised patient populations, more robust and durable protective immunity is needed, as provided by potential next-generation vaccines such as GEO-CM04S1 that induce both strong T cell and antibody responses.”

Individuals with CLL, regardless of their treatment status, typically exhibit less predictable and often insufficient immune responses to the currently authorized COVID-19 vaccines; therefore, such patients may be at higher risk of a lethal COVID-19 infection. GEO-CM04S1 uses a modified vaccinia virus (MVA) viral vector backbone, containing both the Spike (S) and Nucleocapsid (N) antigens of the SARS-CoV-2 virus. Inclusion of both the S and N antigens may be more effective at inducing COVID-19 immunity in patients exhibiting poor antibody responses following receipt of an mRNA vaccine containing only the S antigen as MVA also induces strong T cell expansion, even in the background of immunosuppression. By targeting both the S and N protein antigens, GEO-CM04S1 offers the potential to both broaden the specificity of the immune responses as well as protect against the loss of efficacy associated with current vaccines due to the significant sequence variation observed within the S antigen.

Dodd continued, “This ongoing trial is providing important information about the potential use of GEO-CM04S1 in one of many immune-compromised patient populations. It is also complementary to the pending start of a BARDA-funded 10,000-participant Phase 2b clinical trial to evaluate the efficacy of GEO-CM04S1 versus an approved COVID-19 vaccine as a booster in healthy individuals. We look forward to sharing further progress reports on each of these programs.”

GeoVax Labs, Inc. is a clinical-stage biotechnology company developing novel vaccines for many of the world’s most threatening infectious diseases and therapies for solid tumor cancers. The company’s lead clinical program is GEO-CM04S1, a next-generation COVID-19 vaccine for which GeoVax was recently awarded a BARDA-funded contract to sponsor a 10,000-participant Phase 2b clinical trial to evaluate the efficacy of GEO-CM04S1 versus an approved COVID-19 vaccine. In addition, GEO-CM04S1 is 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. A Phase 2 clinical trial in first recurrent head and neck cancer, evaluating Gedeptin combined with an immune checkpoint inhibitor is planned to initiate during the first half of 2025. GeoVax has a strong IP portfolio in support of its technologies and product candidates, holding worldwide rights for its technologies and products. The company has a leadership team who have driven significant value creation across multiple life science companies over the past several decades. For more information, visit www.geovax.com.