A retrospective analysis of autologous stem cell transplantation conditioning with reduced-dose busulfan/thiotepa for patients with central nervous system lymphomas at a single institution.

INTRODUCTION

Busulfan (BU)- and thiotepa (TT)-containing regimens have been approved for autologous stem cell transplantation (ASCT) in central nervous system lymphoma (CNSL). However, optimal doses of these regimens remain unclear. This study retrospectively analyzed the efficacy and toxicity of the Bu2TT regimen.

METHOD: The study included 12 patients with CNSL who received Bu2TT (BU 3.2 mg/kg, days - 7 and - 6; TT 5 mg/kg, days - 5 and - 4) followed by ASCT at our institution after April 2020.

RESULTS

Four patients were newly diagnosed (primary 3; secondary 1), and eight relapsed (primary 6; secondary 2). The median age was 62 years. Nine patients received high-dose MTX-based regimens as pre-transplant therapy. The other three received tirabrutinib, which was combined with localized radiotherapy (CyberKnife) in one patient. Disease status before ASCT was complete remission (CR) in 7 patients and partial remission in 5. Complications included febrile neutropenia (10/12 patients) and grade 3 anorexia (5/12 patients). Disease status after transplantation was CR in 10 patients and progressive disease in 2. OS and PFS rates at 2 years were 100% and 71%, respectively.

CONCLUSION

Our data suggest that Bu2TT had acceptable safety and efficacy. These results provide a rationale for further analyses in prospective multi-institutional trials.