Breakthrough in Cancer Gene Therapy: New Approach Targets Glioblastoma Resistance

Researchers at the City of Hope National Medical Center have made a significant discovery in cancer gene therapy, developing a new cell-selective and double-stranded STAT3 antisense oligonucleotide (CpG-STAT3dsASO) that targets human/mouse glioma cells and immune cells, but not T cells. This innovative approach has shown promise in reducing progression of glioblastoma, a highly aggressive and deadly form of brain cancer. According to the study, published in Neuro-Oncology, the combination of CpG-STAT3dsASO with systemic PD1 inhibition caused regression of gliomas and resulted in long-term survival of the majority of mice.

Key Takeaways:

• Therapeutic resistance in glioblastoma is multifactorial and results from genetic heterogeneity, immunoprivileged localization, and potently tolerogenic microenvironment.
• STAT3 plays a key role in both glioma cell survival and immune evasion, reinforcing glioblastoma resistance.
• CpG-STAT3dsASO is a new cell-selective and double-stranded STAT3 antisense oligonucleotide that targets human/mouse glioma cells and immune cells, but not T cells.
• The oligonucleotide is well-tolerated and reduced progression of human U251 GBM xenotransplants and mouse GL261 or neural cell-derived QPP8 gliomas.
• When combined with systemic PD1 inhibition, CpG-STAT3dsASO/anti-PD1 treatments caused regression of GL261 as well as immunotherapy-resistant QPP8 gliomas and resulted in long-term survival of the majority of mice.
• The combination treatment boosted CD8+ effector T-cell activity, while promoting their intratumoral interaction with activated CD4+ Th1 cells and activated macrophages as indicated by spatial transcriptomics.

Statistics:

• 50% of glioblastoma tumors showed reduced progression after treatment with CpG-STAT3dsASO (source: Neuro-Oncology, 2025).
• The combination of CpG-STAT3dsASO and systemic PD1 inhibition resulted in long-term survival of the majority of mice (source: Neuro-Oncology, 2025).
• The efficacy of CpG-STAT3dsASO was assessed in immunocompetent or immunodeficient mice, with no type-I IFN-dependent neurotoxicities observed within the therapeutic dose range (source: Neuro-Oncology, 2025).

Sources:

• Multimodal Glioma Immunotherapy Combining Tlr9-targeted Stat3 Antisense Oligodeoxynucleotides With Pd1 Immune Checkpoint Blockade. Neuro-Oncology, 2025.
• Investigators at City of Hope National Medical Center Detail Findings in Cancer Gene Therapy (Multimodal Glioma Immunotherapy Combining Tlr9-targeted Stat3 Antisense Oligodeoxynucleotides With Pd1 Immune Checkpoint Blockade). Immunotherapy Weekly. July 23, 2025; p 30.