CTNI-56. A PHASE II CLINICAL TRIAL USING ACCELERATOR-BASED BNCT SYSTEM FOR REFRACTORY RECURRENT HIGH-GRADE MENINGIOMA

Abstract

Abstract BACKGROUND Boron neutron capture therapy (BNCT) is tumor-selective particle radiation. Recently accelerator-based neutron sources (ABNS) have been developed for clinical trials to obtain on-label use, i.e. new drug approval for malignant gliomas. Recently Japanese regulatory authority has just given this permission for H&N cancers. Recurrent high-grade meningiomas (HGM) are difficult to control. We have applied reactor-based BNCT for 46 cases of refractory HGM. All cases showed good tumor shrinkage with good local control. PURPOSES Based on these situations, we proposed “A phase II clinical trial using accelerator-based BNCT system for refractory recurrent HGM” for AMED in Japan which is similar to NIH in USA. This proposal was successfully accepted. DESIGN We prepared 2 study groups, BNCT test treatment group and control best supportive care group, for RCT. PFS and OS were set-up as primary and secondary endpoints, respectively. Rescue BNCT is allowed for control group patients, if they showed PD during observation. Modified Macdonald criteria is adopted for assessment. Hypothesized PFS of treatment group and control group was 5 months and 24 months, respectively. The trial started in August 2019. METHODS Twelve BNCT and 6 control subjects will be included. Patients’ eligibility criteria is recurrent HGM after some radiotherapy. Cyclotron-based ABNS system is used for neutron source. Neutron-irradiation time is determined not to exceed to 7.5 Gy-Eq for scalp dose which was referencing preceding phase I trial for malignant gliomas. PROGRESS As of April 2020, 4 subjects were included, 3 for BNCT treatment group, 1 for control best supportive care group. The control subject showed PD during one month observation and rescue treatment showed PR. Treatment group 3 cases showed more than SD. CONCLUSION We started this RCT and will introduce the interim report of this clinical trial in the meeting.