Induction of abscopal effect combining H101 oncolytic virotherapy with tislelizumab in a patient with advanced hepatocellular carcinoma: a case report.

We reported a case of advanced hepatocellular carcinoma (HCC) in a patient who relapsed after first-line chemoimmunotherapy. Remarkably, the combination of H101 oncolytic virotherapy and tislelizumab successfully induced an abscopal effect. Following this treatment, the patient achieved a 24-month survival period, accompanied by complete regression of distant metastatic lesions. Distinct tumor responses were observed at different sites following H101 injection. Lesions showing regression demonstrated higher infiltration of CD3 T cells, CD4 T cells, and eosinophils, along with lower infiltration of neutrophils. Rapid tumor shrinkage was associated with severe local inflammation and a reduction in peripheral white blood cell counts. These findings suggest that oncolytic virotherapy may elicit an abscopal effect by activating and recruiting immune cells into the tumor microenvironment.