Feasibility study of autologous peripheral blood stem cell transplantation for the treatment of childhood acute myelogenous leukemia

The role of cytotoxic therapy with hematopoietic stem cell transplantation in the therapy of acute myeloid leukemia in children: an evidence-based review

Clinical research examining the role of hematopoietic stem cell transplantation (SCT) in the therapy of acute myeloid leukemia (AML) in children is presented and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the treatment recommendations. Treatment recommendations based on the evidence are presented in the table entitled "Summary of Treatment Recommendations Made by the Expert Panel for Pediatric Acute Myeloid Leukemia" and were reached unanimously by a panel of experts in AML. The identified priority areas of needed future research in pediatric AML include: What is the role of risk group stratification, including the role of cytogenetics, in selection of patients for allogeneic SCT, especially those in first CR? What is the appropriate timing and use of alternative donor SCT, given that matched unrelated donor SCT appears to yield outcomes equivalent to matched related donor SCT? What is the role of reduced intensity SCT (including the use of fludarabine-based preparative regimens) and/or other immunomodulatory approaches to maximize the graft-versus-leukemic effect? and What is the role of biologically targeted agents (ie, tyrosine kinase inhibitors, farnesyl transferase inhibitors, Flt-3 inhibitors, etc) in the treatment of AML, including induction, consolidation, conditioning regimens, and after SCT?

Allogeneic versus autologous versus peripheral stem cell transplantation in CR1 pediatric AML patients: a single center experience

BACKGROUND

Treatment of childhood acute myelocytic leukemia (AML) in first remission, is still evolving. Allogeneic bone marrow transplantation (BMT) in patients with a donor has been well established, but the role of autologous transplantation remains of interest, particularly in the light of some encouraging results in adults.

PROCEDURE

Out of 81 pediatric patients with AML in first CR, 67 were biologically randomized for allogeneic (n = 31), autologous (n = 20), or peripheral stem cell transplant (n = 16) after completing consolidation treatment, with the remaining (n = 11) dropping out or receiving chemotherapy. Disease free survival (DFS) of these different groups were analyzed.

RESULTS

Allogeneic transplantation is not superior to autologous and autologous peripheral blood stem cell transplantation (PBSCT) (DFS in 5 years is 61%, 50%, and 75%). The 5 years DFS in the autologous PBSCT group is significantly better than in the autologous BMT group (75% vs. 50%, P < 0.05).

CONCLUSION

In pediatric AML patients without a donor, autologous BMT or autologous PBSCT appears to be an effective treatment option with low transplant related mortality especially in less privileged countries where the chemotherapy only results are still low.

New approaches to hematopoietic cell transplantation in oncology

The use of high-dose chemotherapy followed by autologous HCT and the use of allogeneic HCT in children and adolescents with high-risk ALL, AML, and NBL has successfully improved outcomes. For other diseases, however, the role of HCT in treatment remains a subject of further research. The availability of HCT was significantly expanded by developing alternative graft sources that currently include BM, peripheral blood, and UCB from autologous and allogeneic related or unrelated donors. Progress in autologous HCT has been achieved by the identification of more effective and less toxic preparative regimens and by ex vivo purging of stem cell products. In allogeneic HCT, graft-versus-leukemia or graft-versus-tumor effects are being exploited increasingly to lower relapse rates. In addition, immunomodulation to promote tolerance, as well as allogeneic antitumor reactions have been achieved by antibody therapy, cytokine therapy, or cell-based immunotherapy. Future improvements are likely, as evidenced by promising preliminary results in the development of stem cell collection techniques, in vitro stem cell expansion, and purging techniques of stem cell grafts. The development of less intensive or nonmyeloablative preparative regimens may further reduce regimen-related morbidity and mortality Specific immunotherapy may facilitate tolerance induction in mismatched allogeneic HCT and support allogeneic HCT in the setting of donor-host HLA disparity. Ultimately, advances in cytokine therapy, tumor-specific vaccines, and gene therapy may decrease or even eradicate recurrence of the malignant disease after HCT.