Table 1.
Characteristics of pediatric patients undergoing first allogeneic HCT for acute leukemia or MDS compared with the subset who relapsed after HCT
| Variable | All patients (n=93) | Patients who relapsed post-HCT (n=40) | Log-rank p-value for comparison of Relapse Free Survival (Relapse vs No relapse) | ||
|---|---|---|---|---|---|
| Median age at HCT, years (range) | 10 (0.6–21.2) | 9 (0.7–20.2) | NS | ||
| n | n (% of all patients) | ||||
| Gender | Male | 62 (67%) | 29 (47%) | NS | |
| Diagnosis | AML | 41 (44%) | 18 (44%) | NS | |
| ALL. | 34 (37%) | 16 (47%) | |||
| MPAL | 10 (11%) | 4 (40%) | |||
| MDS | 8 (9%) | 2 (25%) | |||
| Disease status at HCT, by disease | AML | Active Disease | 8 (9%) | 5 (63%)# | < 0.01** |
| MRD + CR | 13 (14%) | 6 (46%) | |||
| MRD Neg CR | 20 (22%) | 7 (35%) | |||
| ALL | Active Disease | 1 (8%) | 1 (100%) | ||
| MRD + CR | 13 (14%) | 8 (62%) | |||
| MRD Neg CR | 20 (22%) | 7 (35%) | |||
| MPAL | Active Disease | 1 (8%) | 1 (100%) | ||
| MRD + CR | 1 (8%) | 0 (0%) | |||
| MRD Neg CR | 8 (9%) | 3 (38%) | |||
| MDS | 8 (9%) | 2 (25%) | |||
| Performance Status at HCT | 80–100% | 84 (90%) | 33 (39%) | 0.02 | |
| 40–70% | 8 (9%) | 6 (75%) | |||
| Indication for HCT (For leukemia patients only, n=85) | Primary Induction Failure | 12 (13%) | 6 (50%) | NS | |
| High-Risk Disease* | 24 (26%) | 6 (25%) | |||
| Relapsed Disease | 25 (27%) | 10 (40%) | |||
| Multiple Indications | 24 (26%) | 16 (67%) | |||
| Remission Number (For leukemia patients only, n=85) | CR1 | 41 (44%) | 16 (39%) | NS | |
| CR2 | 27 (63%) | 12 (44%) | |||
| CR3+ | 7 (9%) | 4 (57%) | |||
| Refractory | 10 (11%) | 7 (70%)# | |||
| HCT Conditioning Regimen | Myeloablative | 79 (85%) | 30 (38%) | <0.01 | |
| Reduced Intensity | 14 (15%) | 10 (71%) | |||
| Stem Cell Source | Bone Marrow | 71 (76%) | 34 (48%) | NS | |
| Single Umbilical Cord | 18 (19%) | 6 (33%) | |||
| Double Umbilical Cord | 1 (1%) | 0 (0%) | |||
| Peripheral Blood | 3 (3%) | 0 (0%) | |||
| Donor Type | Matched sibling | 26 (28%) | 11 (42%) | NS | |
| Matched unrelated | 30 (32%) | 12 (40%) | |||
| Cord Blood | 19 (20%) | 6 (32%) | |||
| Haploidentical^ | 15 (16%) | 9 (60%) | |||
| Mismatched related/unrelated | 3 (3%) | 2 (67%) | |||
Abbreviations: ALL=acute lymphoblastic leukemia; AML = acute myelogenous leukemia; MPAL=mixed phenotypic acute leukemia; MDS=myelodysplastic syndrome. Active disease defined by > 5% blasts, including those with refractory disease; CR=complete remission, MRD=minimal residual disease which includes patients with levels > 0.01% by flow cytometry for ALL and > 0.1% for AML/MPAL, or detectable disease by cytogenetics.
High-risk determination was made by transplant physician using a constellation of multiple assessments which included cytogenetics (e.g., monosomy 7, hypodiploid < 43 chromosomes, FLT3/ITD), end-induction MRD positivity and/or phenotype (MPAL) and in conjunction with standard accepted criteria for transplant indications.
p-value is in comparison of relapse free survival for those with active disease to those in a CR.
Many patients who received the initial haploidentical transplants were on an institutional non-myeloablative protocol which also included patients with active disease at the time of transplant.
2 patients with refractory disease prior to HCT died from early TRM before day 100. 1 patient with refractory AML remains a long-term survivor post-HCT without relapse