Regulated intratumoral expression of IL-12 using a RheoSwitch Therapeutic System® (RTS®) gene switch as gene therapy for the treatment of glioma

Cancer Gene Ther. 2018 Jun;25(5-6):106-116. doi: 10.1038/s41417-018-0019-0. Epub 2018 May 14.


The purpose of this study was to determine if localized delivery of IL-12 encoded by a replication-incompetent adenoviral vector engineered to express IL-12 via a RheoSwitch Therapeutic System® (RTS®) gene switch (Ad-RTS-IL-12) administered intratumorally which is inducibly controlled by the oral activator veledimex is an effective approach for glioma therapy. Mice bearing 5-10-day-old intracranial GL-261 gliomas were intratumorally administered Ad-RTS-mIL-12 in which IL-12 protein expression is tightly controlled by the activator ligand, veledimex. Local tumor viral vector levels concomitant with veledimex levels, IL-12-mRNA expression, local and systemic cytokine expression, tumor and systemic flow cytometry and overall survival were studied. Ad-RTS-mIL-12+veledimex elicited a dose-related increase in tumor IL-12 mRNA and IL-12 protein and discontinuation of veledimex resulted in a return to baseline levels. These changes correlated with local immune and antitumor responses. Veledimex crossed the blood-brain barrier in both orthotopic GL-261 mice and cynomolgus monkeys. We have demonstrated that this therapy induced localized controlled production of IL-12 which correlates with an increase in tumor-infiltrating lymphocytes (TILs) leading to the desired biologic response of tumor growth inhibition and regression. At day 85 (study termination), 65% of the animals that received veledimex at 10 or 30 mg/m2/day were alive and tumor free. In contrast, the median survival for the other groups were: vehicle 23 days, bevacizumab 20 days, temozolomide 33 days and anti-PD-1 37 days. These findings suggest that the controlled intratumoral production of IL-12 induces local immune cell infiltration and improved survival in glioma, thereby demonstrating that this novel regulated immunotherapeutic approach may be an effective form of therapy for glioma.

MeSH terms

  • Animals
  • Brain Neoplasms* / genetics
  • Brain Neoplasms* / metabolism
  • Brain Neoplasms* / pathology
  • Brain Neoplasms* / therapy
  • Cell Line, Tumor
  • Gene Expression*
  • Genetic Therapy*
  • Glioma* / genetics
  • Glioma* / metabolism
  • Glioma* / pathology
  • Glioma* / therapy
  • Interleukin-12 / biosynthesis*
  • Interleukin-12 / genetics
  • Mice
  • Neoplasms, Experimental* / genetics
  • Neoplasms, Experimental* / metabolism
  • Neoplasms, Experimental* / pathology
  • Neoplasms, Experimental* / therapy


  • Interleukin-12