Role of Second Hematopoietic Stem Cell Transplantation in Relapsed or Refractory Hematologic Malignancies

Outcomes after Second Hematopoietic Stem Cell Transplantations in Pediatric Patients with Relapsed Hematological Malignancies

Relapse of hematological malignancies after hematopoietic stem cell transplantation (HCT) is associated with poor prognosis. A second HCT represents one of the few therapeutic options for these high-risk patients. For children undergoing second HCT, the outcome data are particularly limited. We, therefore, conducted a retrospective single-institution study and report the outcomes and prognostic variables associated with overall survival (OS) and relapse in 43 pediatric patients who underwent a second HCT between 2000 and 2013. Eleven of the 43 patients who underwent transplantation remain alive and disease-free at a median follow-up of 49 months (range, 5 to 127 months). The 5-year probability of OS for the entire cohort was 24%. Patients who had early relapse (<6 months) after first HCT had significantly worse OS than those who relapsed late (>6 months), with 5-year OS at 11% versus 34%, respectively (hazard ratio [HR], 2.24; 95% confidence interval [CI], 1.21 to 4.93; P = .013). Active disease at time of second HCT was also associated with a significantly increased risk of relapse (subdistribution hazard ratio [SHR], 2.36; P = .049) for the entire cohort and relapse was the most frequent cause of death (23 of 32; 72%). On subgroup analysis for the 34 patients with leukemia alone, presence of active disease was associated both with a significant decrease in OS (SHR, 2.28; 95% CI, 1.02 to 5.09; P = .044) and significant increase in the rate of relapse (SHR, 2.46; P = .046). By contrast, underlying disease, donor source, conditioning regimen, or development of GVHD did not modify OS or rate of relapse. Hence, a second HCT appears to be a useful therapeutic option in children with relapsed hematological malignancies that is most likely to benefit those individuals with late onset of relapse and with low disease burden at the time of transplantation.

The second therapeutic trial for children with hematological malignancies who relapsed after their first allogeneic SCT: long-term outcomes

The impact of a second all-SCT on the long-term outcomes of children who relapse after allo-SCT has been unclear. We retrospectively analyzed the long-term outcomes of different salvage treatments for such children. Sixty-six children with hematological malignancies (40 ALL, 22 AML, three MDS, and one CML) who relapsed after a first allo-SCT received either a second allo-SCT (n = 16) or CTx and/or DLI (n = 50). The median follow-up for all children was 9.1 yr. The five-yr OS after relapse was significantly better in patients who underwent a second allo-SCT (42.9%) than in patients treated with CTx and/or DLI (11.8%) (p < 0.05). However, this advantage diminished with increasing time. The eight-yr OS for these groups of patients were 21.4% and 11.8%, respectively (p = n.s.). Among the 16 patients who received a second allo-SCT, two died more than five yr after the second allo-SCT. A second allo-SCT can therefore lead to a prolonged OS in patients who relapse after allo-SCT. However, a second allo-SCT should be selected carefully. This is because the mortality rate is still high, even when there is an extensive duration of time following the second allo-SCT.

Second allogeneic hematopoietic SCT for relapsed ALL in children

A second SCT is generally accepted as the only potentially curative approach for ALL patients that relapse after SCT, but the role of second SCT for pediatric ALL is not fully understood. We performed a retrospective analysis of 171 pediatric patients who received a second allo-SCT for relapsed ALL after allo-SCT. OS at 2 years was 29.4 ± 3.7%, the cumulative incidence of relapse was 44.1 ± 4.0% and non-relapse mortality was 18.8 ± 3.5%. Relapse occurred faster after the second SCT than after the first SCT (117 days vs 164 days, P=0.04). Younger age (9 years or less), late relapse (180 days or more after first SCT), CR at the second SCT, and myeloablative conditioning were found to be related to longer survival. Neither acute GVHD nor the type of donor influenced the outcome of second SCT. Multivariate analysis showed that younger age and late relapse were associated with better outcomes. Our analysis suggests that second SCT for relapsed pediatric ALL is an appropriate treatment option for patients that have achieved CR, which is associated with late relapse after the first SCT.