ML-17 Clinical usefulness of Tirabrutinib in recurrent PCNSL: single institute experience

Background: Primary central nervous system lymphoma (PCNSL) is a lymphoma whose primary lesion is localized in the brain and spinal cord. Treatment is a combination of high-dose methotrexate-based chemotherapy and whole-brain irradiation, often leading to recurrence. Pathologically, non-GCB type diffuse large B-cell lymphoma (DLBCL) predominates. In DLBCL, constitutive activation of B cell receptor signal (BCR) is the tumor mechanism of tumor development and growth. Tirabrutinib is an inhibitor of Bruton’s tyrosine kinase (BTK) located downstream of BCR. In a phase I / II study, an overall response rate was 64%. Currently, Tirabrutinib is used to treat relapsed or refractory PCNSL. Purpose: Tirabrutinib is a drug that has just been approved, and there are few reports of its use in clinical practice. We report on our experience with Tirabrutinib with a review of the literature. Methods: We retrospectively examined the clinical course of 11 recurrent PCNSL patients treated with Tirabrutinib at our institution. Results: The average age of the subjects was 68.7 years, and 7 cases were male. Tirabrutinib 480 mg was administered in all cases. The response rate was 60% (6/10 cases). The median progression-free survival was 4.3 months. The adverse events were Grade 3 neutropenia in 1 patient and Grade 2 skin disorder in 4 patients. Treatment was discontinued in 5 of the 11 patients due to the progression of the disease. Due to the eruption, Tirabrutinib was reduced to 320 mg in 1 patient and discontinued in 1 patient. Treatment was discontinued at the request of the patient in 1 case, and four patients are still on medication. Summary: According to the results we obtained, the response rate was the same as that in the phase I / II study, and the progression-free survival was slightly longer.