Second autologous hematopoietic stem cell transplantation in multiple myeloma

High-dose melphalan followed by autologous stem cell transplantation (ASCT) is standard in multiple myeloma (MM), but relapse remains inevitable. Second ASCT2 is a salvage option for selected patients with durable remission after ASCT1. Reports from the Asia-Pacific region are limited.

This retrospective study included six patients with relapsed MM who underwent ASCT2 between 2012 and 2025. Demographics, treatment characteristics, toxicity, engraftment, and outcomes were analyzed. All patients underwent fresh stem cell mobilization with granulocyte colony-stimulating factor and plerixafor without cryopreservation.

The median age at ASCT2 was 61 years (range, 47-65 years). The median interval between ASCT1 and ASCT2 was 66 months (range, 31-123 months). Two patients achieved partial remission (PR), 1 achieved very good partial remission (VGPR), and 3 achieved complete remission (CR) before ASCT2. Four patients received melphalan 140 mg/m² and 2 received melphalan 200 mg/m² for ASCT2. The median CD34⁺ cell dose infused during ASCT2 was 2.54 × 10⁶/kg (range, 1.42-21 × 10⁶/kg). Febrile neutropenia developed in 4 patients but was easily controlled with empiric antibiotics. Neutrophil recovery occurred at a median of 11 days (range, 10-14 days), and platelet recovery at 13 days (range, 12-15 days). Hospital stay duration ranged from 15 to 22 days, with a median of 18.5 days. There was no transplant-related mortality. The median follow-up of the study cohort was 28.5 months (range, 1-47 months). Two patients died at 35 and 47 months post-ASCT2, respectively, due to progressive disease. One patient was lost to follow-up after the second bone marrow transplant. Three patients remain alive and in sustained remission.

ASCT2 is a feasible salvage strategy in selected Indian patients with MM, yielding favorable outcomes with acceptable toxicity.