10207- IMT-4 REAL-WORLD DATA AND IMMUNOHISTOLOGICAL STUDY OF AUTOLOGOUS FORMALIN-FIXED TUMOR VACCINE FOR NEWLY DIAGNOSED GLIOBLASTOMA

Abstract BACKGROUND Glioblastoma (GBM) is a highly malignant tumor with a poor prognosis despite advances in treatment. At our institution, an autologous formalin-fixed tumor vaccine (AFTV) has been used as postoperative adjuvant therapy in addition to standard temozolomide and chemoradiotherapy. We present real-world data and analyze the correlation between AFTV, molecular markers, and clinical outcomes in newly diagnosed GBM patients. METHODS This study included 402 newly diagnosed GBM patients treated at our institution between 2005 and 2021. Patients were divided into AFTV (n = 158) and non-AFTV (n = 244) groups. The AFTV group demonstrated a significantly prolonged median progression-free survival (PFS) of 15.0 months compared to 7.8 months in the non-AFTV group (p<0.01) and a median overall survival (OS) of 31.3 months versus 19.4 months (p<0.01). In the subset of 60 patients who underwent gross total resection (GTR), the PFS was 18.4 months, and the OS reached 42.4 months, showing additional benefits. Among 115 elderly GBM patients, typically considered to have a poor prognosis, the AFTV group showed improved outcomes with a PFS of 14.2 months and OS of 27.3 months (p<0.01). In 131 patients who experienced early recurrent within 6 months, AFTV treatment resulted in an OS of 15.1 months compared to 9.4 months in the non-AFTV group (p<0.01). While no significant difference was observed in IDH-mutation, PDL-1 expression analysis in 53 patients revealed that those without PDL-1 expression had a better response to AFTV, with a median OS of 35.3 months compared to 28.4 months in PDL-1 positive patients. CONCLUSION AFTV significantly extends survival in GBM patients, particularly in those with GTR, elderly patients, and early recurrent cases. PDL-1 expression may influence AFTV efficacy, indicating the importance of this marker in ongoing and future clinical trials. Multidisciplinary treatment, including AFTV, offers promising potential for improving patient outcomes.