Orelabrutinib, Rituximab, Temozolomide and High-Dose Methotrexate (RMOT) in Newly Diagnosed Primary Central Nervous System Lymphoma (PCNSL): A Single-center Retrospective Analysis.

Purpose Primary central nervous system lymphoma (PCNSL) is a rare and aggressive malignant tumor with poor prognosis. Orelabrutinib, a highly selective BTK inhibitor, has demonstrated promising clinical effectiveness in patients with relapsed and refractory PCNSL. The purpose of this study was to evaluate the effectiveness and safety of orelabrutinib, rituximab, temozolomide and high-dose methotrexate (RMOT) regimen in the treatment of patients with newly diagnosed PCNSL. Method Patients diagnosed with PCNSL were included in this retrospective study. All patients received at least 4 cycles of RMOT regimen (rituximab 375 mg/m ² iv day 1; MTX 3.5 g/m ² iv day 2; temozolomide 150 mg/m ² po day 1 to day 5; orelabrutinib 150 mg qd po; 4 weeks per cycle), and autologous stem cell transplantation (ASCT) or whole brain radiation therapy (WBRT) was used as consolidation therapy. All patients were proposed to receive orelabrutinib as maintenance therapy for a maxium duration of 2 years. Results 16 treatment-naive PCNSL patients were treated with RMOT regimen. The CRR and ORR were 87.5% and 93.75%, respectively. The median follow-up time was 18.7 months. The median PFS and OS was not achieved. The 1-year PFS and OS rates both reached 90%. The most common adverse reaction was anemia, most adverse reactions were grade 1–2, and only 1 patient (6.25%) occurred grade 3 adverse reactions. Conclusion This retrospective data suggested that RMOT had an encouraging anti-tumor activity in newly diagnosed PCNSL patients, with a toleratable safety profile. Further perspective studies are warranted to validate its effectiveness in untreated PCNSL.