BACKGROUND

Allogeneic stem cell transplantation (allo-SCT) has curative potential and was previously considered by several experts superior to autologous stem cell transplantation (auto-SCT) for patients with multiple myeloma relapsing after first-line auto-SCT.

METHODS

The authors conducted a comprehensive literature review of English-language studies published from 1995 to October 2024. Five studies comparing allo-SCT with second auto-SCT following first line auto-SCT in multiple myeloma were included. Two additional studies comparing patients with or without a suitable allo-SCT donor after relapse were analyzed separately. Individual data from 815 patients were obtained from two large databases: the Japan Society for Hematopoietic Stem Cell Transplantation and the Center for International Blood & Marrow Transplant Research (CIBMTR). Data from five smaller studies (three comparing allo-vs. auto-SCT and two comparing donor vs. no-donor groups) presented via Kaplan-Meier curves were digitized using the Shiny app. Meta-analyses were performed using R 4.3.3. Kaplan-Meier and log-rank tests for overall survival (OS) and progression-free survival (PFS) were conducted in SPSS.

RESULTS

Individual patient data analysis showed significantly longer OS in the auto-SCT group. This benefit was consistent in the three smaller studies. PFS was also superior for auto-SCT in the CIBMTR data set and the pooled smaller studies. In the two-donor vs. no-donor studies, the donor group showed better PFS, with OS also improved when data were combined.

CONCLUSIONS

Allo-SCT after relapse from first line auto-SCT resulted in inferior OS and PFS compared to a second auto-SCT. These findings indicate that allo-SCT should no longer be recommended in patients with multiple myeloma relapsing after first line auto-SCT.