Allogeneic hematopoietic cell transplantation (HCT) is a relatively new option for elderly patients with acute myeloid leukemia (AML) but human leukocyte antigen (HLA)-matched sibling donors are not commonly available for this subset of patients, and searching for unrelated donors requires extensive time and effort. Cord blood transplantation (CBT), therefore, may be an attractive option for elderly patients who need urgent HCT, because of its less stringent requirements for HLA matching and greater availability. To expand the pool of data on CBT for elderly patients with AML, this study assessed the outcomes and prognostic factors for elderly patients with AML undergoing single-unit CBT.
A total of 1577 non–acute promyelocytic leukemia patients with AML aged ≥60 years from the Japan Society for Hematopoietic Cell Transplantation who had received their first allogeneic HCT using single-unit CBT between 2002 and 2017 were included in this retrospective study. A total of 63% of patients (N = 990) were not in remission at the time of CBT, the median body weight was 55.0 kg, the median total nucleated cell dose was 2.67 × 107/kg, and the median CD34+ cell dose was 0.82 × 105/kg. By low-resolution typing, the number of mismatches for HLA-A, -B, and -DR was <2 in 27% (N = 429) of patients and ≥2 in 72% (N = 1135) of patients. The myeloablative conditioning regimen was used in 62% of patients, and a calcineurin inhibitor plus mycophenolate mofetil (MMF)-based graft-versus-host disease (GVHD) prophylaxis was used in 46% of patients. The cumulative incidence of neutrophil engraftment was 80% at 42 days, whereas the cumulative incidence of platelet engraftment was 58% at 70 days. The cumulative incidence of grade 2 to grade 4 acute GVHD at 100 days was 44%; the cumulative incidence of grade 3/4 acute GVHD at 100 days was 16%; and the cumulative incidence of extensive chronic GVHD at 2 years was 14%.
Overall survival was 31% at a median follow-up of 31 months. The cumulative incidences of nonrelapse mortality at 100 days and 3 years were 24% and 41%, respectively, whereas the cumulative incidence of leukemia-related mortality at 3 years was 28%. In a multivariate analysis, the following factors were significantly associated with overall mortality: age ≥70 years (association stronger for age ≥75 years), female sex, performance status (PS) ≥2, adverse karyotype, nonremission status at CBT, HLA mismatch ≥2, myeloablative conditioning, using a GVHD prophylaxis other than methotrexate or MMF, and recent calendar year of CBT. In addition, the following factors were significantly associated with nonrelapse mortality: age ≥70 years (association stronger for age ≥75 years), female sex, PS ≥2, and using a GVHD prophylaxis other than methotrexate or MMF.
Although the risks for engraftment failure and early nonrelapse mortality are potential concerns, single-unit CBT could be an effective treatment option for patients with AML aged ≥60 years.
Reference
Isobi M, Konuma T, Masuko M, et al. Single Cord Blood Transplantation for Acute Myeloid Leukemia Patients Aged 60 Years or Older: A Retrospective Study of the Japan Society for Hematopoietic Cell Transplantation (JSHCT). Presented at: 25th European Hematology Association Congress Virtual; June 11-21, 2020. Abstract S261.