Monotherapy with other drugs (HD-MTX, temozolomide, topotecan, high-dose cytarabine, rituximab, temsirolimus, pemetrexed, and bendamustine) showed ORRs of 30.6%–90.9% (median, 51.0%) and CR/CRu rate of 0%–72.7% (median, 26.2%) in relapsed/refractory PCNSL.9,19 Ibrutinib, a first-generation BTK inhibitor, showed an ORR of 52% (CR/CRu, 19%).20 The current ORR (63.6%) and CR/CRu rate (36.4%) with tirabrutinib were comparable to those results. This evidence concerns the gene BTK and primary central nervous system lymphoma.