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e19041 Background: PCNSL is a rare, aggressive malignant tumor and has a poor prognosis. HD-MTX-based regimen is the first-line treatment of PCNSL. Orelabrutinib is a novel, potent, highly selective BTK inhibitor with a high CSF concentration. Recent evidence has shown the efficacy and safety of orelabrutinib in PCNSL. Therefore, we conducted a retrospective study of clinical outcomes in newly diagnosed PCNSL patients (pts) treated with RMOT regimen in routine clinical care. Methods: This retrospective cohort included the pts (aged 18-80 years) with newly diagnosed PCNSL who received 6 cycles of RMOT regimen (rituximab 375 mg/m2 iv day 1; MTX 3.5 g/m2 iv day 1; temozolomide 150 mg/m2 po day 1 to day 5; orelabrutinib 150 mg qd po; 4 weeks per cycle) as the first-line induction therapy between Nov. 2021 and Aug. 2023. All the pts were proposed to receive orelabrutinib monotherapy as maintenance after RMOT therapy. We recommend to receive autologous stem cell transplantation (ASCT) or whole brain radiation therapy (WBRT) as consolidation after RMOT therapy. Efficacy was assessed by MRI/PET per the International PCNSL Collaborative Group (IPCG) criteria. The primary endpoint was overall response rate (ORR); secondary endpoints were CR rate, progression-free survival (PFS), overall survival (OS), and safety. Results: Ten pts (6 males) with PCNSL were included, with a median age of 61 years (range, 45-77). All pts had a histologically confirmed diffuse large B-cell lymphoma. 4 pts (40%) underwent WBRT after induction therapy. As of the cut-off date (December 31, 2023), the median follow-up time was 9.7 (range, 4.8-25.7) month. All pts were evaluated for the treatment response. An interim evaluation after 4 cycles was available for 10 pts, showing complete remission (CR) rate of 80% (8/10), partial response (PR) rate of 20% (2/10), giving an ORR of 100.0% (10/10, Table). At data cutoff, the best ORR was 100.0% (10/10), with all pts achieved CR. Of 10 responders, 9 had an ongoing response, and 1 died of covid-19 infection. Median PFS/OS was not reached (NR) (95% CI NR-NR). The most common AEs were anemia, other include white blood cell or platelet count decreased. Reported AEs were generally manageable and resolved soon after supportive treatment. Only 1 (10%) pts experienced ≥grade 3 AEs—acute kidney injury. No treatment-related death occurred. Conclusions: This retrospective data suggested that RMOT had an encouraging anti-tumor activity in newly diagnosed PCNSL pts, with a toleratable safety profile. This orelabrutinib-containing regimens may provide a potential treatment strategy for pts with PCNSL. Table: see text
Xia et al. (Sat,) studied this question.