IMT-1 PROS AND CONS OF SURGICAL INTERVENTION FOR DIFFUSE MIDLINE GLIOMA AIMED AT DENDRITIC CELL IMMUNOTHERAPY

Since a diffuse midline glioma (DMG) has no effective therapy, it is an urgent need to develop new therapeutic strategy. We performed immunotherapy using fusions of autologous dendritic cells (DC) with tumor cells in DMG cases in which tumor tissue was collected by surgery aimed at biopsy, and evaluate the effectiveness and examine the pros and cons of surgical intervention against DMG. Among the patients with basal ganglia or brain stem tumors received surgery at our hospital, 5 adult cases of DMG with H3K27M gene mutation were registered. All patients received radiation therapy and temozolomide chemotherapy. 4 cases received bevacizumab chemotherapy when the patients had recurrence or progression of the disease. The tumor-fused DCs (TFDC) were made by DCs induced from autologous peripheral blood mononuclear cells and tumor cells established from surgical specimens. They were injected subcutaneously into the neck 3 ~ 6 times in a 14 ~ 28 day cycle as the immunotherapy. The adverse events, PFS, and OS were evaluated. A transient complication of facial numbness was observed in one case on right after surgery. Although two patients had CR in those therapies, both of them died of disease (OS at 18 and 32 months, respectively). Since the remaining three cases were registered very recently, adverse event or treatment efficacy judgment have not been determined at the time of submission of the abstract. Serious surgical complications have not been observed in the presented cases. Surgery may be acceptable for DMG as long as the surgery is performed by sufficiently experienced surgeon in an appropriate environment. The TFDC immunotherapy, which can be performed only by collecting a small amount of tumor tissue, expects to be a novel treatment for MDG. In this presentation, the pros and cons of surgical intervention aimed at TFDC immunotherapy for DMG will be examined.