Ddre-18. therapeutic effects of tasquinimod on glioblastoma

Abstract Glioblastoma is the most aggressive and most common primary malignant brain tumor in adults. This disease is still incurable despite multimodal therapies. We evaluated Tasquinimod, an oral HDAC4 inhibitor, in use with oncolytic HSV therapy. Tasquinimod is known to bind to HDAC4 and S100A9 to modulate myeloid population and angiogenesis in the tumors. This drug is being clinically evaluated in prostate and other solid tumors and multiple myeloma. However, the therapeutic effect of Tasquinimod in glioblastoma is not known. We found that Tasquinimod could change the immune-suppressive phenotype of MDSCs and polarize M2 macrophages towards M1 phenotype in ex vivo assay using mouse bone marrow cells treated with glioma conditioned media. We also tested Tasquinimod and oncolytic HSV in murine CT2A in C57/B6 mice and primary human GBM xenograft model in athymic mice. While the therapeutic effect of Tasquinimod or oHSV alone was not significant or marginal, the combo group show significantly longer survival. The study of underlying mechanisms is still ongoing. In conclusion, Tasquinimod combined with oncolytic HSV could have a better therapeutic effect on glioblastoma.