Feasibility and Safety of Autologous Dendritic Cell Vaccination Combined with Radio-Chemotherapy in Newly Diagnosed Glioblastoma: A Retrospective Single-Center Series

BACKGROUND: The prognosis of glioblastoma (GBM) patients remains poor. Dendritic cell (DC) vaccination has been investigated as an immunotherapy option, mainly in early-phase clinical studies. Herein, we report the feasibility, safety, and descriptive clinical and radiological outcomes of a retrospective series of newly diagnosed GBM patients treated with standard radio-chemotherapy and autologous DC vaccination as compassionate use. METHODS: We retrospectively reviewed the medical and radiological records of patients with newly diagnosed GBM who received autologous tumor lysate-pulsed DC vaccination in addition to standard-of-care treatment at a tertiary academic center between 2009 and 2017. Clinical data, treatment characteristics, adverse events, survival outcomes, and radiological responses were collected and analyzed descriptively. RESULTS: Twenty-four patients were included. All patients underwent surgical resection and were further treated with autologous tumor lysate-DC vaccination and standard radio-chemotherapy. Histology of GBM was confirmed in all patients. The first vaccine was administered in 75% of patients after a median of 21 days (range: 6-30 days) following surgery and prior to radiotherapy initiation. DC vaccination was continued following radiotherapy at specific time points, with no observed significant adverse events. Median OS was 21.1 months (95% CI, 27.9-75.0 months), and median PFS was 10.3 months (95% CI, 15.6-26.6 months). Presence of O6-methylguanine DNA methyltransferase (MGMT) promoter methylation was associated with longer survival and higher 12-month PFS rates, consistent with its established prognostic value. Radiological responses were retrospectively assessed according to RANO and RANO 2.0 criteria. CONCLUSIONS: In this retrospective single-center series, autologous DC vaccination administered as compassionate use in combination with standard radio-chemotherapy was feasible and safe in routine clinical practice. Survival and radiological outcomes are reported descriptively and should be interpreted with caution given the absence of a control cohort. These findings support further prospective controlled studies to properly assess the clinical role of DC vaccination in newly diagnosed GBM.