| Abstract: | Allogeneic stem cell transplantation (allo‐SCT) offers a clinical option to young patients with multiple myeloma (MM) relapsing/progressing after autologous SCT (ASCT); however, this claim remains debatable. Thus, in this retrospective study, we analyzed 526 patients with MM who underwent SCT for MM relapsing/progressing after the prior ASCT using the registry data of the Japan Society for Hematopoietic Cell Transplantation (2001‐2015) and compared overall survival (OS) between allo‐SCT (n = 192) and autologous stem cell retransplantation groups (ReASCT; n = 334) based on risk factor points. Significant adverse factors for OS in all patients were (1) male sex, (2) less than partial response to SCT, (3) performance status of 2 to 4, and (4) short duration from the prior ASCT. We scored factor 2 as 1 point, factor 3 as 2 points, and factor 4 as 0, 1, or 2 points for more than 30, 9 to 30, or less than 9 months, respectively. We categorized patients into three risk subgroups based on their total points (0, 1‐3, and 4‐5 points), indicating the usefulness of this scoring system for prognosis prediction and treatment selection. Subgroup comparison revealed OS after ReASCT to be higher than that after allo‐SCT in the intermediate‐risk subgroup comprising the largest population (28.2% vs 21.5%, P < .004). We observed no significant advantages of allo‐SCT over ReASCT in the low‐ and high‐risk subgroups. These findings suggest that ReASCT is more advantageous than allo‐SCT in many patients with MM relapsing/progressing after the prior ASCT. However, long‐term survival patients were noted only in the allo‐SCT group, and allo‐SCT could exhibit clinical efficacy, particularly in the low‐risk group. While further examination is warranted, allo‐SCT could be a potential tool for a specific population with MM relapsing/progressing after the prior ASCT. |
