GeoVax Labs, Inc. announced the publication of a peer-reviewed article in JCO Oncology Advances, the American Society of Clinical Oncology's open-access journal, reporting findings from a Phase 1/2 clinical trial of Gedeptin in patients with recurrent head and neck cancer. The study enrolled patients who had exhausted all standard treatment options and had undergone a median of four prior lines of systemic therapy, representing a highly refractory population.
The trial evaluated repeated cycles of Gedeptin, a gene-directed enzyme prodrug therapy administered via intratumoral injection followed by systemic fludarabine. Key results included an acceptable safety profile with no new safety signals, where serious adverse events were uncommon and generally unrelated to treatment, and no deaths were attributed to study therapy. Clinical evidence of disease stability was observed, with three of eight patients achieving stable disease in this cohort of end-stage disease patients.
Importantly, tumor biopsies confirmed successful tumor transduction and PNP transgene expression in all evaluable patients, supporting the mechanistic foundation of the Gedeptin platform. This finding validates the therapy's approach of using a non-replicating adenoviral vector to deliver the E. coli purine nucleoside phosphorylase gene directly into tumor tissue, where it activates fludarabine into a potent cytotoxic metabolite called 2-fluoroadenine.
The study results suggest that earlier intervention, higher vector dosing, improved tumor transduction, or combination therapy may further increase efficacy. Preclinical findings cited in the manuscript show that Gedeptin-mediated tumor destruction may sensitize tumors to checkpoint inhibitors, offering a promising path forward for combination treatments. J. Marc Pipas, MD, Executive Medical Director, Oncology of GeoVax, stated that the publication reinforces the strong scientific rationale underpinning the Gedeptin platform, noting that even in this refractory population, repeated intratumoral dosing demonstrated a favorable safety profile and evidence of disease stability.
Kelly T. McKee, MD, MPH, Chief Medical Officer of GeoVax, added that these results support continued development of Gedeptin in settings where tumor burden is lower, patients are less heavily pretreated, or where combination strategies, particularly with immune checkpoint inhibitors, may amplify therapeutic benefit. This aligns with the company's strategy to advance Gedeptin into neoadjuvant studies for surgically resectable recurrent head and neck cancers.
David Dodd, Chairman & CEO of GeoVax, stated that the publication in the ASCO journal underscores both the scientific significance of this trial and the need for new approaches to treat recurrent head and neck cancers. Gedeptin's targeted mechanism, combined with its repeat-dosing feasibility, offers a promising therapeutic option for patients. The company looks forward to expanding development into earlier disease settings and rational combination regimens.
Gedeptin features a tumor-agnostic mechanism of action driven by localized intratumoral activation of fludarabine into the potent cytotoxin F-Ade, enabling activity independent of tumor histology or proliferation rate. It also exhibits a strong bystander effect, where the activated F-Ade diffuses to neighboring cancer cells, allowing Gedeptin to kill tumor cells even when only a small fraction is directly transduced. Additionally, the therapy has immune-sensitizing properties that enhance tumor antigen visibility and may improve responses to immune checkpoint inhibitors.
The favorable safety profile demonstrated across early Phase 1 and Phase 1/2 studies is particularly significant given the consistent tolerability in heavily pretreated solid tumor patients. Gedeptin is now progressing toward combination therapy in a neoadjuvant clinical program, building on robust preclinical data showing that Gedeptin enhances tumor sensitivity to immune checkpoint blockade. GeoVax is advancing plans to evaluate Gedeptin with agents such as pembrolizumab aiming to strengthen antitumor immune activation. For more information about clinical trials and other updates, visit https://www.geovax.com.
