10082-RT-1 LONG-TERM RESULTS OF A BNCT PHASE II CLINICAL TRIAL USING AN ACCELERATOR-BASED NEUTRON SOURCE FOR PATIENTS WITH RECURRENT GLIOBLASTOMA

Abstract PURPOSE Accelerator-based neutron sources have received regulatory approval and boron neutron capture therapy (BNCT) for head and neck cancer has been introduced into clinical treatment in earnest. BNCT is a radiotherapy with cell-selective characteristics, and its application to highly invasive malignant gliomas (MG) is the origin of its development. This study reports the long-term results of a phase II study of accelerator-based BNCT (AB-BNCT) using a cyclotron-based neutron source (BNCT30) and a boronophenylalanine product (SPM-011) in patients with recurrent MG. METHODS A phase 2 clinical trial (JG002) in 27 patients with recurrent malignant glioma (MG) (24 with glioblastoma (GB)) was conducted using SPM-011 and BNCT30. Eligibility criteria were radiation re-irradiation with MG not previously treated with bevacizumab and patients relapsing after standard of care (radiotherapy and chemotherapy with temozolomide). The primary endpoint was one-year survival from BNCT treatment, and secondary endpoints included median overall survival (mOS) and median progression-free survival (mPFS). The 1-year survival and mOS of patients with relapsed GB in JG002 were 79.2% (95% CI: 57.0-90.8) and 18.7 months, respectively. The current long-term observation resulted in an mOS of 19.2 months (95% CI: 13.1-24.8) and survival rates of 33.3 and 20.8% at 2 and 3 years from treatment, respectively. The adverse event was cerebral edema, and 21 of the 27 patients received bevacizumab treatment after decision of disease progression (PD) on imaging. CONCLUSION AB-BNCT showed an acceptable safety and survival benefit in relapsed MG, predominantly GB. Following BNCT treatment, the tumor may have shown a contrast enhancement in the irradiated field, with associated brain edema. BNCT showed a survival benefit in patients with recurrent malignant gliomas, even in the long term.