Abstract
In the absence of an HLA identical donor, T-cell depleted haploidentical hematopoietic stem cell transplantation (HSCT) is an alternative option to treat children with high risk or relapsed acute leukaemia. However very few data is available in a large series of children. With the aim to study risk factors of outcomes we have analyzed 196 children (<16 years old) with ALL (n=131) or AML (n=65) transplanted with a T-cell depleted bone marrow (n=18) or peripheral blood related haploidentical HSCT from 1995 to 2004 in Europe. The median age was 8 years and median follow-up 22 months. In the AML group, 13 (20%) children were transplanted in CR1, 22 (34%) in CR2 and 30 (46%) in advanced phase and in ALL group, 28 (21%) in CR1, 74 (56%) in CR2 and 81 (62%) in more advanced phase. The majority of the patients did not receive drugs for GVHD prophylaxis and all received myeloablative conditioning (61% of TBI). Cumulative incidence with competing risk and KM estimates were used to calculate outcomes probabilities. The median days of neutrophil recovery was 14 days (4–72) and 85% of patients had signs of engraftment. Acute GVHD II–IV was observed in 17% of the patients (8% had grade III–IV). Two-years overall LFS, relapse incidence and TRM were 27±4%, 43±3%, 30±3%, respectively. Patients transplanted with AML or ALL had similar outcomes. LFS was 28±6%for AML and 27±4% for ALL. Among the risk factors analysed only the disease status at transplantation was associated with LFS and relapse incidence. Outcomes are listed below according to disease status at transplant.
| Outcomes at two years . | CR1 (n=41) . | CR2 (n=74) . | Advanced (n=81) . | p value . |
|---|---|---|---|---|
| Transplant related mortality | 32+/−8% | 26+/−5% | 33+/−5% | 0.44 |
| Relapse | 32+/−8% | 40+/−6% | 51+/−6% | 0.03 |
| Leukaemia free survival | 36+/−8% | 34+/−6% | 16+/−4% | <0.0001 |
| Outcomes at two years . | CR1 (n=41) . | CR2 (n=74) . | Advanced (n=81) . | p value . |
|---|---|---|---|---|
| Transplant related mortality | 32+/−8% | 26+/−5% | 33+/−5% | 0.44 |
| Relapse | 32+/−8% | 40+/−6% | 51+/−6% | 0.03 |
| Leukaemia free survival | 36+/−8% | 34+/−6% | 16+/−4% | <0.0001 |
In fact, in a multivariate analysis for LFS and relapse only patients transplanted in remission had better LFS and decreased relapse incidence compared with non remission patients (p<0.001 and p=0.006, respectively). No risk factor was found to be associated with TRM. Most frequently, causes of death were relapse (60%) or infections (22%). In conclusion, haploidentical HSCT is an alternative option to treat children with high risk acute leukaemia in the absence of HLA identical donor.
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