rG47-PRS1

rG47-PRS1 is an engineered oncolytic herpes simplex virus (oHSV) derived from the G47Δ backbone, specifically designed for the treatment of PAX3-FOXO1 (P3F) positive alveolar rhabdomyosarcoma (aRMS). The virus incorporates a synthetic P3F-responsive promoter—constructed from a PRS1 element and a minimal Myogenin promoter—to drive the expression of the cytotoxic ICP34.5 gene. This mechanism ensures that viral replication and subsequent tumor cell lysis occur selectively in cells expressing the PAX3-FOXO1 fusion protein. Preclinical studies demonstrate that rG47-PRS1 not only exhibits direct cytotoxicity but also activates the NF-kB pathway and enhances the infiltration of CD45+ lymphocytes, thereby sensitizing immunologically cold aRMS tumors to immune checkpoint inhibitors like anti-PD1 antibodies.