P-350: A retrospective comparison of single versus tandem transplant in newly diagnosed Multiple Myeloma: a real-world study

Introduction: Autologous stem cell transplant (ASCT) has been the backbone of therapy in newly diagnosed Multiple Myeloma (NDMM). The main issue regarding ASCT has been the debate between single or tandem transplant to further improve progression free survival (PFS). Only a few studies have been published and almost all predate recently introduced treatment options. The aim of this retrospective analysis is to compare the progression-free survival (PFS) of Single Transplant (ST) versus Tandem Transplant (TT) in patients with newly diagnosed multiple myeloma in a real-world setting.

Methods: Data from 30 patients with newly diagnosed multiple myeloma who underwent ASCT after induction treatment with VTD and a follow-up >24 months at a single center from 2018 to 2023 were analyzed. 21 underwent ST and 8 underwent TT. The PFS of the two groups was compared using Kaplan-Meier survival analysis.

Results: The median PFS of the ST group was 35.5 months, while that of the TT group was 39.5 months.

Conclusions: ASCT has been a fundamental aspect of the therapy in multiple myeloma, despite the introduction of numerous drugs. Indeed, the introduction of Daratumumab and, more recently, the first trials exploring the use of CAR-T products as alternative to ASCT has reduced the absolute need to transplant patients with NDMM. Even more, numerous studies demonstrated the toxicity of tandem myeloablative treatment regarding the bone marrow and the potential risk of developing mutations and secondary neoplasms.
This retrospective single-center analysis suggests that there is no significant difference in PFS between ST and TT in patients with multiple myeloma. Despite the small sample size and the retrospective nature of the data, these findings are consistent with previous studies and provide further evidence that TT does not confer a significant advantage over ST in terms of PFS. ASCT as consolidation in NDMM has still significant relevance due to the experience regarding its use compared to CAR-T or bispecific antibodies. Despite the incredible evolution in MM treatment, ASCT and especially ST can be considered a valuable resource for patients with NDMM.