# Efficacy and safety of the thiotepa–busulfan conditioning regimen as for autologous stem cell transplantation in relapsed/refractory systemic diffuse large B cell lymphoma: a single-center retrospective study

## TL;DR

This study shows that the thiotepa–busulfan regimen is effective and safer than alternatives for treating relapsed/refractory lymphoma with stem cell transplants.

## Contribution

The study provides evidence that the TT/BU regimen offers better survival and fewer side effects in DLBCL patients undergoing ASCT.

## Key findings

- The TT/BU regimen showed 84.4% 3-year progression-free survival and 91.7% overall survival.
- The TT/BU group experienced fewer severe adverse events, especially related to kidney function.
- TT/BU is a well-tolerated and effective alternative to other conditioning regimens for DLBCL.

## Abstract

High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) is a standard treatment for relapsed diffuse large B cell lymphoma (DLBCL). The BEAM regimen is widely used, but the MEAM regimen is more common in Japan due to the unavailability of carmustine. This retrospective analysis evaluated the efficacy of the thiotepa and busulfan (TT/BU) regimen compared with other regimens in 27 patients with systemic DLBCL who underwent ASCT at our institution from December 2013 to March 2022. Fourteen patients received the TT/BU regimen, while 13 received alternative regimens. The TT/BU regimen demonstrated superior progression-free survival (PFS) and overall survival (OS) compared to other regimens, with a 3 year PFS of 84.4% and OS of 91.7%. The TT/BU group also had fewer severe adverse events, particularly regarding renal function. Our findings suggest that the TT/BU regimen is a well-tolerated and effective alternative for relapsed/refractory DLBCL and provide valuable insights for future treatment strategies.

The online version contains supplementary material available at 10.1007/s12185-025-03946-w.