Direct Second Autologous Stem Cell Transplantation Versus Re-Induction Followed by Transplantation in Relapsed...

Area of Science:

• Hematology
• Oncology
• Stem Cell Transplantation

Background:

• Uncertainty exists regarding the optimal strategy for relapsed multiple myeloma (MM): immediate second autologous stem cell transplantation (ASCT2) or pre-ASCT2 re-induction chemotherapy.
• Real-world data on the comparative impact of these pre-ASCT2 strategies on survival outcomes are limited due to patient selection and heterogeneity in treatment allocation.
• ASCT2 is a salvage therapy typically reserved for selected relapsed MM patients.

Purpose of the Study:

• To evaluate real-world outcomes of ASCT2 in relapsed MM patients based on pre-ASCT2 management.
• To compare progression-free survival after ASCT2 (PFS2) and overall survival (OS) between patients undergoing direct ASCT2 versus those receiving re-induction chemotherapy prior to ASCT2.

Main Methods:

• A multicenter retrospective cohort study involving 42 relapsed MM patients who underwent ASCT2 between 2012 and 2024.
• Patients were categorized into two groups: direct-ASCT2 (n=21) and re-induction chemotherapy prior to ASCT2 (n=21).
• Survival outcomes (PFS2, OS) were analyzed using Kaplan-Meier methods and multivariable Cox regression.

Main Results:

• Median PFS2 was 19.7 months overall, with no significant difference between direct-ASCT2 (21.3 months) and re-induction (13.8 months) groups (p=0.790).
• Median OS was 48.2 months. Unadjusted OS was longer in the direct-ASCT2 group (51.7 vs. 39.6 months, p=0.019), but this difference was not significant after multivariable adjustment.
• Post-ASCT2 response rates were comparable, and day-100 transplant-related mortality was low (2.4%).

Conclusions:

• Pre-ASCT2 re-induction chemotherapy did not demonstrate a clear improvement in PFS2 compared to proceeding directly to ASCT2 in this real-world cohort.
• Observed differences in unadjusted OS likely stem from confounding by indication and selection bias, highlighting the challenges of retrospective comparative analyses.
• These findings are hypothesis-generating and contribute to the limited real-world evidence base for ASCT2 in highly selected relapsed MM patients.