Enhanced Therapeutic Efficacy for Glioblastoma Immunotherapy with a New Generation Oncolytic Herpes Simplex Virus Armed with Anti-PD-1 Antibody and IL-12

Glioblastoma is the most common and aggressive malignant brain tumor with limited treatment options. Hence, innovative approaches are urgently needed. Oncolytic virus therapy is emerging as a promising modality for cancer treatment due to its tumor-specific targeting and immune-stimulatory properties. In this study, we developed a new generation of oncolytic herpes simplex virus C5252 by deletion of 15-kb internal repeat region and both copies of γ34.5 genes. Additionally, C5252 was armed with anti-PD-1 antibody and IL-12 to enhance its therapeutic efficacy for glioblastoma immune-virotherapy. In vitro and in vivo experiments demonstrate that C5252 has a remarkable safety profile and potent anti-tumor activity against glioblastoma. Mechanistic studies demonstrated that C5252 specifically induces cell apoptosis by caspase 3/7 activation via downregulating ciliary neurotrophic factor receptor α (CNTFRα). Furthermore, the enhanced anti-tumor therapeutic efficacy of C5252 in subcutaneous glioblastoma model and orthotopic glioblastoma model was confirmed. Moreover, syngeneic mouse models showed that the murine surrogate of C5252 has superior anti-tumor activity than the unarmed backbone virus with enhanced immune activation. Taken together, our findings support C5252 as a promising therapeutic option for glioblastoma treatment, positioning it as a highly promising candidate for clinical translation.