Tandem Autologous-Autologous versus Autologous-Allogeneic Hematopoietic Stem Cell Transplant for Patients with Multiple Myeloma: Long-Term Follow-Up Results from the Blood and Marrow Transplant Clinical Trials Network 0102 Trial.

• Long-term follow-up of auto-auto versus auto-allo in newly diagnosed multiple myeloma patients confirms significant and durable reduction in risk of relapse with the auto-allo approach. • Auto-allo transplant is associated with better 6-year PFS for high-risk patients. • Patients who relapsed after auto-allo had longer postrelapse survival than patients who relapsed after auto-auto transplant. Allogeneic hematopoietic cell transplant (HCT) may improve long-term multiple myeloma (MM) control through the graft-versus-myeloma effect. The Blood and Marrow Transplant Clinical Trials Network 0102 trial was a biologic assignment trial comparing tandem autologous transplant (auto-auto) versus autologous followed by reduced-intensity allogeneic (auto-allo) transplant in patients with newly diagnosed MM with standard-risk (n = 625) or high-risk (n = 85; β 2 -microglobulin at diagnosis ≥ 4 mg/dL or deletion of chromosome 13 by conventional karyotyping) disease. Although the initial 3-year analysis showed no difference in progression-free survival (PFS) between arms in either risk group, we hypothesized that long-term follow-up may better capture the impact of the graft-versus-myeloma effect. Median follow-up of survivors was over 10 years. Among standard-risk patients there was no difference in PFS (hazard ratio [HR], 1.11; 95% confidence interval [CI],.93 to 1.35; P =.25) or OS (HR, 1.03; 95% CI,.82 to 1.28; P =.82). The 6-year PFS was 25% in the auto-auto arm versus 22% in the auto-allo arm (P =.32), and 6-year overall survival (OS) was 60% and 59%, respectively (P =.85). In the high-risk group, although there was no statistically significant difference in PFS (HR,.66; 95% CI,.41 to 1.07; P =.07) and OS (HR, 1.01; 95% CI,.60 to 1.71; P =.96), a reduction in 6-year risk of relapse of 77% versus 47% (P =.005) was reflected in better PFS of 13% versus 31% (P =.05) but similar OS, at 47% versus 51% (P =.69). Allogeneic HCT can lead to long-term disease control in patients with high-risk MM and needs to be explored in the context of modern therapy. [ABSTRACT FROM AUTHOR]