Abstract
BACKGROUND: Tirabrutinib, a Bruton’s tyrosine kinase (BTK) inhibitor, was newly approved in 2020 as a treatment option for refractory or relapsed primary central nervous system lymphoma (PCNSL). However, there are limited real-world, long-term data on its efficacy and safety. We conducted a retrospective analysis of our institutional experience with tirabrutinib for PCNSL, focusing on treatment outcomes and adverse events. METHODS: We retrospectively analyzed 13 patients with PCNSL who received tirabrutinib at Kyoto University Hospital since 2020. Patient characteristics, prior treatment history, indications for tirabrutinib initiation, radiological response, changes in activities of daily living (ADL, assessed by Karnofsky Performance Status), progression-free survival (PFS), overall survival (OS), and treatment-related adverse events were evaluated. RESULTS: The overall response rate (≥PR) was 61.5%. Median PFS was 10 months (mean 7.3 months), and median OS was 18 months. ADL was maintained or improved in most cases, with clinical improvement also observed in patients with EBV-associated PCNSL. Adverse events included mucocutaneous inflammation and cytopenia; dose reduction or treatment interruption was required in 2 patients (15.4%), but no severe adverse events were observed. CONCLUSIONS: Our findings suggest that tirabrutinib offers favorable efficacy and acceptable safety for refractory or relapsed PCNSL. It may be a viable option even for treatment-resistant and EBV-associated cases, potentially contributing to improved prognosis. Further accumulation of cases and prospective studies are warranted.