CTNI-12. TIRABRUTINIB FOR RECURRENT/REFRACTORY PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMA –A SINGLE-INSTITUTION RETROSPECTIVE ANALYSIS–

Abstract BACKGROUND Tirabrutinib is a second-generation, highly selective oral Bruton’s tyrosine kinase inhibitor and approved for the treatment of recurrent/refractory primary central nervous system lymphoma (PCNSL) in Japan. We reviewed our single institution experiments of tirabrutinib. MATERIALS AND METHODS Our institutional review board approved this retrospective study. Twenty-eight patients with recurrent or refractory PCNSL treated with tirabrutinib at our institution between 2020 and 2024 were included. Information regarding the patient’s age, gender, imaging findings, pathological results, including immunostaining findings, and treatment information, including chemotherapy and radiation therapy, was obtained from medical records. RESULTS Tirabrutinib was administered to 14 patients with recurrent cases (20-85 years old, median 69.5 years old, 9 males and 5 females), 14 with refractory cases (59-87 years old, median 74 years old, 9 males and 5 females). Three male patients received rechallenge with tirabrutinib against re-relapsed. We assessed the effectiveness of tirabrutinib and observed complete response (CR) in 12 cases, partial response (PR) in 1 case, and progressive disease (PD) in 1 case among refractory patients. In recurrent cases, we observed CR in 8 cases, PR in 1 case, stable disease (SD) in 3 cases, and PD in 2 cases. In rechallenge for re-relapsed cases, we observed CR in 2 cases and PD in 1 case. The progression-free survival following beginning of tirabrutinib was 12.95 months for refractory cases and 8.2 months for recurrent cases. The overall survival was 25 months for refractory cases and 12.8 months for recurrent cases. One patient each experienced CTCAE grade 3 interstitial pneumonia or liver failure, both of which improved after discontinuing the medication. Four patients exhibited grade 1-2 skin rashes. CONCLUSIONS Tirabrutinib demonstrates efficacy and high tolerability for the treatment of recurrent/refractory PCNSL in real-world settings.