Virotherapy for Spinal and Spinal Cord Tumors: Current Evidence and Future Perspectives

Tumors of the spine and spinal cord, including primary and metastatic vertebral tumors, intramedullary gliomas, and refractory intradural lesions, are challenging to treat because curative local therapy is limited by the eloquent, nonregenerating neural tissue surrounding them. Oncolytic virotherapy may offer a rational alternative by combining tumor-selective oncolysis with the induction of systemic antitumor immunity, while sparing normal neural cells. This review summarizes the current field of oncolytic viruses, including adenovirus, herpes simplex virus, reovirus, and others, in the context of spinal and spinal cord tumors. Clinical data in the spine remain scarce; however, the rationale is based on histological evidence from sarcomas and other tumors, extensive glioma experience, including diffuse intrinsic pontine glioma, and preclinical activity in nerve sheath and meningioma models. We discuss the telomerase-specific oncolytic adenovirus OBP-301 and its derivatives, whose hTERT-driven replication provides histology-agnostic tumor selectivity, while sparing the telomerase-silent spinal cord. This telomerase dependence, however, limits activity against tumors that maintain telomeres through the alternative lengthening of telomeres (ALT) pathway, such as many osteosarcomas and some spinal cord astrocytomas. We also discuss delivery and safety within the confined spinal canal, combination strategies, and future directions, such as extracellular vesicle-mediated delivery and biomarker-guided patient selection. Although clinical translation to the spine will require dedicated preclinical and early-phase studies, virotherapy represents a promising, mechanistically grounded modality for these therapeutically challenging tumors.