Atlanta-based biotech GeoVax outlines how its multi-antigen MVA platform addresses critical gaps left by single-antigen vaccines, with three Phase 2 COVID-19 trials underway and a Phase 3 Mpox vaccine trial scheduled for H2 2026

Founded in 2001 from Emory University’s Vaccine Center, GeoVax has evolved from its original HIV vaccine focus into a multi-platform developer addressing some of the most underserved patient populations in infectious disease and oncology. The company’s current pipeline spans three distinct therapeutic areas: a next-generation COVID-19 vaccine targeting immunocompromised patients, an Mpox/smallpox vaccine addressing global supply constraints, and Gedeptin®, a gene-directed enzyme prodrug therapy for solid tumors.

Addressing the 40 Million Patient Gap in COVID-19 Protection

GeoVax’s lead infectious disease program, GEO-CM04S1, represents a strategic pivot toward patients who fail to respond adequately to authorized COVID-19 vaccines. “There are over 40 million such adults in the U.S. alone; >400 million worldwide,” notes CEO David Dodd, highlighting the scale of unmet need among immunocompromised populations.

The company is currently advancing three separate Phase 2 trials for GEO-CM04S1. The first evaluates the vaccine as a booster for adults previously vaccinated with mRNA vaccines, with data readout scheduled for H2 2025. The second targets blood cancer patients receiving stem cell transplantation or CAR-T therapy, directly comparing GEO-CM04S1 to either Pfizer or Moderna mRNA vaccines. This trial is actively expanding, with UK sites anticipated during H1 2026.

The third trial, focusing on Chronic Lymphocytic Leukemia (CLL) patients, has already demonstrated the limitations of current approaches. “The interim results were reviewed, resulting in the Data Safety Monitoring Board noting that the Pfizer arm failed to meet the pre-determined endpoint, subsequently halting the Pfizer arm,” Dodd explains. “The GeoVax vaccine exceeded the pre-determined endpoint; the remainder of the study is based only on receipt of the GEO-CM04S1 vaccine and is anticipated to complete patient enrollment by the end of 2025.”

Breaking the Mpox Vaccine Monopoly

Beyond COVID-19, GeoVax is addressing supply constraints in the Mpox/smallpox vaccine market. “Today there is a single supplier (monopoly) distributing the Mpox/smallpox vaccine, not having sufficient production capacity to meet global existing and expanding demand,” Dodd states. The company’s GEO-MVA vaccine has received an unprecedented regulatory pathway from the European Medicines Agency, with exemption from conducting Phase 1 or Phase 2 trials and proceeding directly to a Phase 3 immuno-bridging trial scheduled for H2 2026.

Manufacturing Strategy: From Eggs to Continuous Cell Lines

GeoVax’s manufacturing approach reflects both current capabilities and future scalability ambitions. The company currently utilizes CDMO partnerships for early-stage production while developing a more advanced platform for long-term growth.

“For our infectious disease vaccines, the company is advancing a continuous avian cell line-based manufacturing process for its MVA vaccines to reduce reliance on egg-based platforms, anticipated to result in more rapid production, higher yield at reduced cost,” Dodd explains. This transition addresses one of the industry’s persistent bottlenecks while aligning with U.S. policy priorities for pandemic preparedness infrastructure.

The shift from traditional egg-based production to continuous cell lines represents both a technical and strategic evolution. “The transition from small-scale vector production to a robust, scalable system has required optimization of yield, purity, and viral stability,” Dodd notes. The company is addressing these challenges through process development tied to its continuous cell line platform, working toward cGMP-readiness for the MVA manufacturing system.

For its oncology program, Gedeptin®, GeoVax maintains a different manufacturing strategy focused on qualified CDMO relationships with U.S.-based production capabilities as the program advances toward registration.

Scientific Differentiation Through Multi-Antigen Design

The core differentiator in GeoVax’s infectious disease platform lies in its multi-antigen approach. “GeoVax’s MVA infectious disease platform delivers multiple antigens, producing broad and durable immune responses encompassing both antibody and cellular arms. Unlike mRNA or other single-antigen approaches, this approach appears to offer enhanced efficacy across variants and subtypes,” Dodd explains.

This design philosophy directly addresses the limitations exposed in immunocompromised populations, where single-antigen vaccines fail to generate adequate protection. The CLL trial results underscore this advantage, with the company’s multi-antigen vaccine succeeding where the mRNA comparator failed to meet endpoints.

Oncology Expansion with Targeted Tumor Therapy

GeoVax’s third priority area, Gedeptin®, represents a departure from its vaccine expertise into targeted cancer therapy. The gene-directed enzyme prodrug therapy delivers genes directly into tumors, followed by systemic administration of a non-toxic prodrug, creating localized cytotoxicity with minimal systemic effects.

Based on encouraging Phase 1 and Phase 1/2 results in advanced head and neck cancer—funded by the FDA under its Clinical Trials program due to unmet need—GeoVax is preparing a Phase 2 trial as first-line therapy with curative intent, scheduled for H2 2026. The program has received Orphan Drug Status and shows promise as a “tumor agnostic” approach across multiple solid tumor types.

Financial Foundation and Strategic Partnerships

To date, GeoVax has raised approximately $70 million through public offerings, government contracts, and strategic partnerships. The funding has supported the company’s evolution from a single HIV vaccine focus to its current multi-platform approach, enabling advancement from preclinical status to multiple ongoing Phase 2 trials since its Nasdaq uplisting in September 2020.

The company’s development strategy leverages extensive government relationships, including long-standing collaborations with NIH, CDC, and BARDA. “GeoVax’s development trajectory has been supported by long-standing relationships with the NIH, CDC, Emory University, and government funding bodies such as NIAID and BARDA,” Dodd notes, emphasizing the value of public-private partnerships in biotech development.

Navigating Clinical Development Challenges

GeoVax’s clinical experience spans the complexities of both vaccine and oncology development, each presenting distinct challenges. “Challenges encountered during clinical development have included trial site variability, pandemic-related logistical constraints, and the evolving regulatory landscape for both oncology and vaccine products,” Dodd explains.

The company has adapted through decentralized trial models where feasible and partnerships with experienced CROs and academic collaborators. For oncology trials, this has required “careful patient stratification and biomarker planning to support future combination strategies.”

Near-Term Milestones and Strategic Priorities

GeoVax’s 12-18 month roadmap encompasses advancement across all three priority programs. For GEO-MVA, the focus centers on regulatory interactions with FDA and EMA, including pursuit of expedited pathways such as PRIME designation, leading to the H2 2026 Phase 3 initiation.

The COVID-19 vaccine program presents multiple inflection points: H2 2025 results from the booster trial, H1 2026 completion of the CLL study, and continued enrollment in the blood cancer patient trial comparing GEO-CM04S1 to mRNA vaccines.

For Gedeptin®, the company is finalizing manufacturing, CMC, and clinical operations to support the Phase 2 neoadjuvant trial combining Gedeptin® with immune checkpoint inhibitors.

Manufacturing readiness represents another critical milestone, with the company progressing toward cGMP-readiness for its MVA continuous cell line platform while pursuing additional funding and strategic partnerships for late-stage development and worldwide commercialization.

Strategic Advice for Fellow Biotechs

Reflecting on GeoVax’s 23-year evolution, Dodd emphasizes adaptability as a core success factor. “From a development standpoint, GeoVax has observed that platform adaptability is key to navigating both scientific and policy shifts. Regulatory science is increasingly responsive to public health imperatives, particularly in areas like pandemic preparedness, oncology, and biodefense.”

For early-stage biotechs, he highlights the importance of demonstrating both scientific merit and practical feasibility. “For early-stage biotechs, the ability to demonstrate translational relevance and manufacturing feasibility—particularly in the context of public-private collaboration—can be as critical as the underlying science.”

As Dodd concluded, “Most of all, learn from your competitors, collaborators, regulators and anyone having experienced the challenges of a biotech company evolution. Always remember to remain flexible, focused on your goals, respect and learn from your team…and, HAVE FUN!!”