GeoVax Labs, Inc. (Nasdaq: GOVX) has announced significant advancements for its gene-directed enzyme prodrug therapy, Gedeptin, including an expanded patent portfolio and promising clinical data supporting its potential in treating solid tumors.
Patent Portfolio Expansion
The biotechnology company has secured new patent claims covering the synergistic combination of Gedeptin therapy with radiation as a targeted approach for solid tumors. The allowed claims describe a method for treating various cancers—including glioblastoma, breast, prostate, head and neck, glioma, and lung cancers—through a triple-combination strategy designed to generate localized cytotoxic activity within the tumor microenvironment while minimizing systemic toxicity.
This approach involves:
- Direct intratumoral administration of an adenoviral vector encoding purine nucleoside phosphorylase (Ad/PNP)
- Local administration of the prodrug fludarabine phosphate (F-araAMP)
- Subsequent radiation therapy
The newly allowed patent joins GeoVax's growing Gedeptin intellectual property portfolio, which was exclusively licensed through a prior agreement with PNP Therapeutics, Inc. and the University of Alabama at Birmingham (UAB)/Southern Research.
"This allowed patent underscores the clinical and commercial promise of our Gedeptin platform and demonstrates our commitment to expanding therapeutic options for patients with difficult-to-treat cancers," said David Dodd, Chairman and CEO of GeoVax. "While the claims do not directly mirror our ongoing clinical programs, they establish a critical foundation for future directions, including potential integration with advanced delivery systems for tumors that are challenging to access."
Promising Clinical Data Presented at AACR
At the American Association for Cancer Research (AACR) Annual Meeting 2025, GeoVax presented new clinical data on Gedeptin in a presentation titled "Viral-Vectored, Gene-Directed Prodrug Therapy (Gedeptin) in Needle-Accessible Solid Tumors." The study, conducted in collaboration with researchers from Stanford Cancer Center, Emory University School of Medicine, Vanderbilt University, and Thomas Jefferson University, evaluated the safety and efficacy of repeated cycles of Gedeptin in patients with advanced head and neck cancer.
The trial enrolled eight heavily pretreated patients who had received a median of four prior lines of systemic therapies. The treatment regimen consisted of up to five cycles, each involving intratumoral injection of Gedeptin followed by intravenous administration of fludarabine.
Key findings from the study included:
- Several patients achieved stable disease despite extensive prior therapy
- Median progression-free survival (PFS) and overall survival (OS) were both 7.0 months
- No dose-limiting toxicities were reported
- Treatment-related adverse events were minimal, with injection site pain being the most common
- Serious adverse events observed in five patients were mostly attributed to the underlying disease
"These clinical results reinforce the potential of Gedeptin as a tumor-targeted therapy for patients with advanced, refractory cancers," said Kelly T. McKee, Jr., M.D., Chief Medical Officer of GeoVax.
Mechanism of Action and Therapeutic Potential
Gedeptin employs a unique mechanism of action that makes it particularly promising for treating solid tumors. The therapy uses a non-replicating adenoviral vector encoding the E. coli enzyme purine nucleoside phosphorylase (PNP). When injected directly into a tumor and followed by systemic administration of the prodrug fludarabine phosphate, PNP enzymatically converts the prodrug into a cytotoxic metabolite (fluoroadenine), resulting in selective killing of tumor cells by disrupting RNA and protein synthesis.
This tumor-targeted approach offers several key advantages:
- Localized cytotoxicity with reduced systemic side effects
- Potential synergy with immune checkpoint inhibitors
- Applicability across multiple solid tumor types, particularly those accessible for intratumoral injection
Gedeptin has been granted Orphan Drug Designation by the U.S. FDA for intratumoral treatment of oral and pharyngeal cancers.
Phase 2 Trial on the Horizon
Following the encouraging results from the Phase 1/2a study, GeoVax is advancing preparations for a Phase 2 clinical trial evaluating Gedeptin in combination with pembrolizumab (Keytruda) as a neoadjuvant therapy for primarily relapsed squamous cell head and neck cancer.
Preclinical evidence supports the hypothesis that Gedeptin sensitizes tumors to immune checkpoint inhibitors, potentially enhancing clinical response. This combination approach could represent a significant advancement in the treatment landscape for patients with recurrent head and neck cancers, who currently face limited therapeutic options.
Broader Corporate Portfolio
Beyond Gedeptin, GeoVax is advancing several other clinical programs, including GEO-CM04S1, a next-generation COVID-19 vaccine currently in three Phase 2 clinical trials. The company is also developing GEO-MVA, a vaccine targeting Mpox and smallpox.
With a strong intellectual property portfolio now standing at over 135 granted or pending patent applications spread across 23 distinct patent families, GeoVax is well-positioned to continue developing innovative therapies for both cancer and infectious diseases.
As the company moves forward with its Gedeptin development program, the focus will be on validating the therapy's efficacy in combination with established immunotherapies and potentially expanding its application to other solid tumor types that could benefit from this targeted approach.
