A group of investigators, spearheaded by scientists from Massachusetts General Hospital and the Dana-Farber Cancer Institute, demonstrated that a single injection of an oncolytic virus—a genetically altered virus targeting and selectively destroying cancer cells—can effectively recruit immune cells into brain tumors and ensure their sustained presence there. The study, documented in the journal Cell, outlines how this specific treatment prolonged survival for individuals afflicted with glioblastoma, the most common and aggressive form of primary brain cancer, during a recent clinical trial.
“Glioblastoma patients have historically not benefited from the immunotherapy approaches that have revolutionized the treatment of other cancers, such as melanoma, primarily because glioblastoma constitutes a ‘cold’ tumor, meaning it has poor infiltration by cancer-fighting immune cells,” explains co-author Kai Wucherpfennig, MD, head of the Department of Cancer Immunology and Virology at the Dana-Farber Cancer Institute. “The findings from our clinical study indicate that it is now feasible to introduce these crucial immune cells into the glioblastoma environment.”
The oncolytic virus employed in this trial is derived from a genetically modified herpes simplex virus, designed solely to replicate within glioblastoma cells, leaving healthy tissue untouched. The virus enters a glioblastoma cell, leads to its demise, and subsequently produces progeny viruses that then infect neighboring glioblastoma cells. This viral infection process concurrently triggers a robust immune response. In the initial phase of the trial involving 41 patients with recurrent glioblastoma, treatment with the oncolytic virus resulted in extended overall survival compared to historical outcomes, with the most significant benefits observed in patients who already possessed pre-existing antibodies against the virus.
The research team closely examined the magnitude of the resultant immune response among trial participants. Their analysis revealed that the intervention successfully induced a lasting infiltration of immune T-cells within the patients’ tumors. A more intimate engagement between cytotoxic T-cells and the dying brain tumor cells correlated with longer survival times post-treatment. Furthermore, the therapy was shown to boost the population of T-cells already residing within the brain tissue.
“An increase in the number of T-cells actively attacking the tumor cells delivers a therapeutic benefit for glioblastoma patients,” states Chiocca, the study’s lead author. “Our results could signify a major shift for a type of cancer treatment that has seen no significant advancement in two decades.” Information sourced from the portal “Scientific Russia” (https://scientificrussia.ru/)
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