Allogeneic Hematopoietic Cell Transplantation in Multiple Myeloma: Impact of Disease Risk and Post Allograft Minimal Residual Disease on Survival.

BACKGROUND: Allogeneic hematopoietic cell transplantation (allo-HCT) is a potentially curative option for multiple myeloma (MM). We analyzed our experience of allo-HCT in MM and examined outcomes in 77 consecutive patients with MM receiving allo-HCT from matched sibling (n = 69) or unrelated donors (n = 8). The primary objectives were to assess overall survival (OS), progression-free survival (PFS), and non-relapse mortality in these patients.

PATIENTS AND METHODS: Sixty-six patients received non-myeloablative/reduced-intensity conditioning regimens, while 11 received myeloablative regimens. The median follow-up of survivors was 50 months (range, 2.3-129.3 months).

RESULTS: Twenty-seven (35.1%) patients had high-risk cytogenetics at diagnosis (t (4:14), 17p deletion, chromosome 1 abnormality, or t (14:16)). All of patients except 1 had prior auto transplant. On multivariate analysis, older age (hazard ratio [HR], 1.055; 95% confidence interval [CI], 1.001 = 1.11; P = .04), less than complete remission (CR) at allo-HCT (HR, 4.3; 95% CI, 1.3-14.1; P = .006), and cytomegalovirus reactivation (HR, 3.2; 95% CI, 1.38-7.6; P = .002) were associated with higher mortality risk. Less than CR at allo-HCT was also associated with higher risk for non-relapse mortality (HR, 5.8; 95% CI, 1.3-26.3; P = .02). There was no difference in OS or PFS between high-risk and standard-risk cytogenetics. No difference in OS and PFS was seen in those who had morphological complete response regardless of the minimal residual disease status.

CONCLUSION: Allotransplant benefited younger patients and those in CR at the time of transplant. The adverse effect of high-risk cytogenetics may be overcome by the allo-HCT.