BACKGROUND: Most patients (pts) undergoing high-dose therapy and autologous transplant for multiple myeloma (MM) develop disease recurrence. The optimal salvage treatment for these patients is not well defined. Autologous (auto-) and allogeneic (allo-) hematopoietic stem cell transplantation (SCT) have been used for salvage therapy.

METHODS: We performed a retrospective analysis of pts with MM (n=118) treated in our institution who had failed after 1st-line therapy or relapsed after auto-SCT. Re-induction was performed with TCED (thalidomide, cyclophosphamide, etoposide and dexamethasone, median number of cycles 3). Seventy-four pts (median age, 59 yrs) received auto-SCT as salvage therapy, whereas 44 pts (median age, 53 yrs, p=0.43) underwent a reduced-intensity allo-SCT (related in 23 pts), using conditioning with 2 Gy total body irradiation and fludarabine in 40 pts or melphalan 140 mg/m2 / fludarabine in 4 pts. The majority of the pts (37 / 44) received allo- SCT a median of 59 (range 33–186) days after auto-SCT. Twenty pts in the auto-group and 9 pts in the allo-group were primary progressive, respectively (p=0.42).

RESULTS: 89 pts (75%) responded to TCED chemotherapy (CR 4 pts, PR 65 pts, MR 22 pts, SD 13 pts). The number of pts progressing after TCED was equal in both groups (p=0.54). Remission status improved in 30 pts after auto-SCT (7 CR) and in 20 pts after allo-SCT (16 CR, p=0.001). After a median follow-up of 24 months for the auto-group and 21 months for the allo-group since the end of TCED therapy, the median event-free survival (EFS, figure 1) and overall survival (OS, figure 2) were 14 months in both groups (p=0.37) and 27 months versus 35 months (p=0.75), respectively. Incidence of chronic GvHD was 82% (62% extensive). TRM was 20% in the allo-group and differed significantly from the auto-group (1%, p=0.007). Three years after end of TCED 12/44 pts are alive (6 pts in CR) in the allo-group compared to 15/74 pts (1 pt in CR) in the auto-group. All but 1 pt with CR > 3 years after allo-SCT have extensive cGvHD.

CONCLUSIONS: Both auto- and allo-SCT are feasible as salvage therapy for MM. Disease recurrence or progression remains the major cause of treatment failure. More CRs and more long term survivors in CR have been observed after allo-SCT confirming the contribution of the GvM-effect. Further concepts are necessary to maintain CR, to prevent relapse or progression and to reduce TRM after allo-SCT.

Disclosure: No relevant conflicts of interest to declare.

Author notes

*

Corresponding author

Sign in via your Institution