A multicenter randomized phase II/III trial of salvage treatment for refractory primary central nervous system lymphoma using tirabrutinib: JCOG2314 (ReSTART).

Primary central nervous system lymphoma (PCNSL) is an aggressive malignancy. Patients refractory to high-dose methotrexate-based induction therapy have an extremely poor prognosis. Although whole-brain radiotherapy (WBRT) is the standard salvage treatment and provides potent tumor control, early functional deterioration and late neurocognitive toxicity remain major concerns. A phase I/II trial on relapsed or refractory PCNSL demonstrated favorable efficacy and tolerability of tirabrutinib, a second-generation selective Bruton's tyrosine kinase inhibitor. Tirabrutinib's oral administration has enabled outpatient management. However, its clinical value for induction-refractory PCNSL remains uncertain. We designed a multicenter, randomized phase II/III trial (JCOG2314) to assess the non-inferiority of tirabrutinib to WBRT in overall survival and its potential to reduce functional deterioration and cognitive impairment. A total of 94 patients from 49 institutions will be enrolled over 4 years. The trial has been registered in the Japan Registry of Clinical Trials (study number: jRCT1031250645).