Comparative analysis of single versus tandem autologous stem cell transplantation in patients with multiple myeloma in Korea: the KMM2102 study.

Tandem autologous stem cell transplantation can improve the prognosis of patients with multiple myeloma. However, the precise role of tandem transplantation remains debatable. We evaluated the clinical benefits of tandem transplantation retrospectively. Of the 655 included patients, 117 underwent tandem transplantation; the remaining were assigned to the control group. After a single transplantation, the tandem group achieved a complete remission (CR) rate of 24.8%, which increased to 46.2% after a second transplantation. The tandem group had a significantly longer median PFS than the control group in patients with International Staging System (ISS) III and high-risk cytogenetics (23.1 vs. 14.7 months, p = 0.007 for ISS III; 21.7 vs. 13.2 months, p = 0.042 for high-risk cytogenetics). The tandem group exhibited significantly superior PFS to the control group (20.3 vs. 12.6 months, p = 0.003) among patients who failed to achieve CR after a single transplantation. Tandem transplantation was associated with significantly improved PFS after adjusting for maintenance therapy in patients with ISS III, those with high-risk cytogenetics, and those who did not achieve CR after a single transplantation. Following propensity score matching, the tandem group exhibited significantly longer PFS than the control group (30.3 vs. 13.5 months, p = 0.028). Tandem transplantation should be considered in high-risk patients.