Childhood acute myeloid leukemia: outcome in a single center using chemotherapy and consolidation with busulfan/cyclophosphamide for bone marrow transplantation

Pediatric Autologous Hematopoietic Stem Cell Transplantation: Safety, Efficacy, and Patient Outcomes. Literature Review

Autologous stem cell transplantation (auto-HSCT) is a part of the therapeutic strategy for various oncohematological diseases. The auto-HSCT procedure enables hematological recovery after high-dose chemotherapy, otherwise not tolerable, by the infusion of autologous hematopoietic stem cells. Unlike allogeneic transplant (allo-HSCT), auto-HSCT has the advantage of lacking acute-graft-versus-host disease (GVHD) and prolonged immunosuppression, however, these advantages are counterbalanced by the absence of graft-versus-leukemia. Moreover, in hematological malignancies, the autologous hematopoietic stem cell source may be contaminated by neoplastic cells, leading to disease reappearance. In recent years, allogeneic transplant-related mortality (TRM) has progressively decreased, almost approaching auto-TRM, and many alternative donor sources are available for the majority of patients eligible for transplant procedures. In adults, the role of auto-HSCT compared to conventional chemotherapy (CT) in hematological malignancies has been well defined in many extended randomized trials; however, such trials are lacking in pediatric cohorts. Therefore, the role of auto-HSCT in pediatric oncohematology is limited, in both first- and second-line therapies and still remains to be defined. Nowadays, the accurate stratification in risk groups, according to the biological characteristics of the tumors and therapy response, and the introduction of new biological therapies, have to be taken into account in order to assign auto-HSCT a precise role in the therapeutic strategies, also considering that in the developmental age, auto-HSCT has a clear advantage over allo-HSCT, in terms of late sequelae, such as organ damage and second neoplasms. The purpose of this review is to report the results obtained with auto-HSCT in the different pediatric oncohematological diseases, focusing on the most significant literature data in the context of the various diseases and discussing this data in the light of the current therapeutic landscape.

Busulphan given as four single daily doses of 150 mg/m2 is safe and effective in children of all ages

We examined the effects of busulphan (BU) dose and patient age on toxicity and outcome in 63 children with acute leukaemia given BUCY prior to allogeneic or autologous BMT. BU was administered as four single daily oral doses, based either on weight (4 x 4 mg/kg) or surface area (4 x 150 mg/m2). BU pharmacokinetic analysis was not used to dose adjust. The average daily (mg/kg) BU dose was 43% higher for the group given 150 mg/m2 compared to the 4 mg/kg dose group. This produced a median BU AUC 61% higher than with the 4 mg/kg dose. Only one child did not achieve full allogeneic donor engraftment. Regimen-related toxicity was low. Although younger children had faster BU clearance, the 4 x 150 mg/m2 dose ensured equivalent systemic exposure to BU, and resulted in a high frequency of engraftment without a significant increase in serious toxicity. BU, given as four single daily doses of 150 mg/m2, is appropriate and safe in all age groups of children. Given the reliable pharmacokinetics, low toxicity and high rate of allogeneic engraftment, there is no need for routine pharmacokinetic monitoring or dose modifications. This dosage regimen may be applicable for use with i.v. BU.

Update in childhood acute myeloid leukemia: recent developments in the molecular basis of disease and novel therapies

Childhood acute myeloid leukemia is a heterogeneous group of disorders that remains challenging to treat. There are multiple common genetic alterations in childhood acute myeloid leukemia. These include chromosomal translocations affecting RUNX1-CBFbeta, RARalpha, and MLL. There are known activating mutations in the genes for the receptor tyrosine kinases FLT3, KIT, and FMS. As these abnormalities are better understood, they are providing important insights into the pathogenesis of disease as well as information about prognosis. Although intensive chemotherapy remains the mainstay of acute myeloid leukemia therapy, long-term cure rates with chemotherapy alone remain approximately 50%, creating an urgent need for better therapies. Multiple avenues are being explored in the design of new treatments for pediatric acute myeloid leukemia. Targeted therapies include targeted antibody therapy; inhibitors of FLT3, KIT, and farnesyltransferase; diphtheria toxin conjugated to the granulocyte-macrophage colony-stimulating factor; and antisense oligonucleotides. Another area of interest is chromatin remodeling and differentiation therapy, including agents such as all- retinoic acid, arsenic trioxide, and inhibitors of DNA methylation and histone deacetylation. There are also ongoing trials of antiangiogenesis agents. Another avenue for novel therapies is immunotherapy with agents such as interleukin-2 and tumor vaccines. This article reviews recent advances in understanding of the molecular basis for childhood acute myeloid leukemia and the design of novel therapies for the treatment of childhood acute myeloid leukemia.

Results of consecutive trials for children newly diagnosed with acute myeloid leukemia from the Australian and New Zealand Children's Cancer Study Group

Despite improvements in the treatment of acute myeloid leukemia (AML), approximately 50% of children die of the disease. Clinical trials in adult patients with AML indicate that idarubicin may have superior efficacy when compared to daunorubicin in the remission-induction phases of chemotherapy. We conducted consecutive clinical trials in children with newly diagnosed AML in which daunorubicin (group 1, n = 102) or idarubicin (group 2, n = 160) was used during the remission-induction (RI) and the early consolidation phases of chemotherapy. Idarubicin was given at a dose of either 10 mg/m(2) (group 2A, n = 106) or 12 mg/m(2) (group 2B, n = 53). A high rate of RI was achieved for all groups (95% group 1, 90% group 2A, 94% group 2B). There were no significant differences in 5-year event-free survival (EFS) or in overall survival (OS) when the 3 groups were compared (group 1: EFS 50%, OS 56%; group 2A: EFS 50%, OS 60%; group 2B: EFS 34%, OS 50%). RI deaths resulting from treatment toxicity were low-2% for group 1 and 5% for group 2. More gastrointestinal, pulmonary, and renal toxicity but fewer infections were observed in patients receiving idarubicin (P <.001, P =.04, P =.03, respectively). Following RI chemotherapy, all patients received 3 to 4 more courses of identical chemotherapy and then underwent either autologous (n = 156) or an allogeneic bone marrow transplantation (BMT) (n = 35). OS was higher in allogeneic BMT patients than in autologous BMT patients (79% vs 63%; P =.23). We conclude that daunorubicin is as effective as idarubicin for remission-induction therapy for childhood AML and has reduced toxicity.

Bone marrow transplantation for paediatric AML in first remission: a systematic review and meta-analysis

For children with AML in CR1, the major consolidation therapies are BMT, ABMT and intensive chemotherapy. The relative effectiveness of these strategies is still debated. We conducted a systematic review and meta-analysis of trials to determine the effectiveness of BMT and ABMT in CR1 in paediatric AML. Eligible studies enrolled patients <21 years from 1985 to 2000 with AML in CR1. Two groups of studies were identified: (1) Those comparing the outcome of patients with and without a histocompatible family donor; and (2) Randomised controlled trials (RCT) comparing ABMT with non-myeloablative chemotherapy. The relative risk statistic was calculated for outcomes of interest in each trial. If there was no excessive heterogeneity between trials the results were pooled, and an overall relative risk and risk difference for treatment effect across trials were calculated. Results of the analysis showed that allocation to BMT reduced risk of relapse and improved disease-free and overall survival. For ABMT, heterogeneity of effect between RCTs prevented pooling of results. In conclusion, BMT from a histocompatible family donor improves patient outcome. Data are insufficient to determine whether this is true for all subgroups of AML, and whether ABMT is superior to non-myeloablative chemotherapy. An individual patient data meta-analysis is required to further evaluate the available data.

Scedosporium infection in immunocompromised patients: successful use of liposomal amphotericin B and itraconazole

BACKGROUND

Invasive fungal disease is a major cause of death in immunocompromised patients. The filamentous fungus Scedosporium consists of two species, S. prolificans and S. apiospermum, which can cause infections in immunocompromised patients that are often fatal. A significant feature of this pathogen is its broad resistance to many antifungal agents, including amphotericin B.

PROCEDURE AND RESULTS

Five cases of infection with Scedosporium spp. occurred in patients with haematologic malignancies over a 10-month period. Three patients with S. prolificans were severely immunosuppressed and neutropenic; two were in relapse and another was early post-matched unrelated bone marrow transplant. All three died despite treatment with various combinations of amphotericin B and itraconazole. Two patients who were less immunosuppressed and had a normal neutrophil count developed S. apiospermum infection. Both were successfully treated with liposomal amphotericin B and itraconazole.

CONCLUSIONS

Disseminated infection in immunocompromised hosts with Scedosporium spp. is often fatal. However, in patients with a lesser degree of immunocompromise and particularly in those infected with the less virulent S. apiospermum, intensive antifungal therapy with liposomal amphotericin B and itraconazole may be associated with complete eradication of infection. Med Pediatr Oncol 2001;37:122-125.

Hematopoietic stem cell transplantation (HSCT) with a conditioning regimen of busulfan, cyclophosphamide, and etoposide for children with acute myelogenous leukemia (AML): a phase I study of the Pediatric Blood and Marrow Transplant Consortium

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) is an important treatment modality for children with AML. The optimal conditioning regimen is unknown. The aim of this study was to determine the appropriate dosing of etoposide in combination with busulfan and cyclophosphamide in this setting.

PROCEDURE

Twenty patients with a diagnosis of AML in first or second remission, or myelodysplasia scheduled for bone marrow transplantation, were included in this study. Patients received busulfan 640 mg/m(2) in 16 doses, cyclophosphamide 120 to 150 mg/kg in two doses, and etoposide from 40-60 mg/kg as a single dose. Extensive toxicity data was collected.

RESULTS

Nineteen patients were evaluable for toxicity. Mucositis was seen in all patients. Four patients developed bacteremia and one patient died from overwhelming sepsis on day +3. Four patients developed moderate to severe skin toxicity. The major dose-limiting +3 toxicity was hepatic toxicity, which occurred in 14 of 19 patients. Eight patients developed clinical veno-occlusive disease, including three patients at dose level 4, two of whom had life-threatening disease. This hepatic toxicity defined the MTD of 640 mg/m(2) busulfan, 120 mg/kg of cyclophosphamide, and 60 mg/kg of etoposide. Overall, 9 of 20 patients enrolled in the study survive in remission, 8/14 allogeneic (median follow-up 44 months), and one of six autologous patients (follow-up, 54 months).

CONCLUSIONS

We conclude that the combination of busulfan, cyclophosphamide, and etoposide at the doses defined above has activity in the treatment of children with high-risk AML/MDS undergoing allogeneic HSCT. Whether it offers an advantage over other conditioning regimens will require a randomized trial with a larger cohort of patients.

Growth and endocrine function in children with acute myeloid leukaemia after bone marrow transplantation using busulfan/cyclophosphamide

Longitudinal studies of growth and endocrine function of children with AML transplanted with BUCY are limited. We report a cohort of 23 children with AML transplanted (15 autologous and eight allogeneic) following a single chemotherapy protocol and surviving at least 2 years after BMT. Busulfan was given as a single daily dose. Growth and endocrine function was evaluated yearly from one up to 10 years post transplant (median 4.9 years). The mean height standard deviation score (HtSDS) of the entire group decreased from 0.01 (s.e.m. +/- 0.25) at diagnosis to -0.38 (+/- 0.28) at BMT (P = 0.001). There was no statistically significant difference between HtSDS at BMT and yearly HtSDS from 1 to 5 years post BMT. There was no significant relationship between age at BMT and subsequent change in HtSDS. To date, five of six girls have needed sex steroid replacement. Six of 12 evaluable boys had abnormal gonadotrophins, but none required sex steroid replacement. Children with AML who undergo BMT with BUCY show no significant growth impairment, but gonadal dysfunction is prominent, particularly in girls. Bone Marrow Transplantation (2000).

Late effects of chemotherapy compared to bone marrow transplantation in the treatment of pediatric acute myeloid leukemia and myelodysplasia

BACKGROUND

As more pediatric patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) survive, comparison of the late effects of various therapies becomes increasingly important. This study of survivors of AML is the largest to date comparing the late effects of patients treated with chemotherapy (CT) with or without irradiation (RT) or CT followed by bone marrow transplantation (BMT).

PROCEDURE

In a retrospective review of 228 patients with AML or MDS from 1970 to 1995, 62 survived and had follow-up data available more than 1 year following completion of therapy. Ten patients with Down syndrome were excluded. Twenty-six received CT and 26 underwent BMT. Weight and height Z scores, endocrine, ophthalmologic, renal, and cardiac function following CT +/- RT or BMT +/- total body irradiation (TBI) were compared at a mean follow-up of 7.4 and 5.6 years, respectively.

RESULTS

Both groups experienced a decrement in height and increase in weight. The mean height Z score in the CT group fell from -0.29 to -0.72 (P = 0.02) and mean weight Z score rose from -0.06 at diagnosis (T0) to 0.51 at last follow-up (T2) (P = 0.02), a finding no longer significant when patients who received RT were excluded. The mean height Z score in the BMT group fell from -0.17 at TO to -0.65 at T2 (P = 0.02), while the mean weight rose from 0.29 at T0 to 0.84 at T2, (P = 0.07). Six of 9 BMT adolescent girls experienced ovarian failure versus 0 of 11 girls treated with CT (P = 0.002). Seven adolescent CT males and seven BMT males showed normal pubertal progression. Two BMT patients require thyroid hormone supplementation, and one receives growth hormone. Six BMT patients and one CT patient developed cataracts, all of whom received irradiation (P = 0.10). Serum creatinine level, hypertension, or left ventricular shortening fraction were not different in the two groups. One BMT patient has chronic graft versus host disease.

CONCLUSIONS

Growth, renal, and cardiac functions were similar in the two groups. The need for estrogen supplementation was more frequent following BMT. Recommendations concerning therapy for AML should depend on the probability of cure.

The present role of bone marrow and stem cell transplantation in the therapy of children with acute leukemia

Hematopoetic stem cell transplantation (SCT) often represents a unique opportunity for curing children with leukemia. Nevertheless, selecting the patient who could really benefit from this procedure remains a controversial issue. The current consensus is as follows: About 20% of children with ALL can be defined as high-risk patients by criteria such as t(9;22), t(4;11), no complete remission at day 42, poor prednisone response, and T-immunophenotype or pre-pre B-ALL, myeloid markers or more than 100,000 white blood cells/microliter. This high-risk group is eligible for alloBMT in first remission, provided a family-matched donor is available. At relapse the majority of patients will benefit from alloBMT, and alternative donor sources can be considered in high-risk patients. Only early alloBMT relapses (up to 6 months after end of initial therapy) are sure candidates, whereas late relapses, especially extramedullary sites, may equally benefit from an intensive conventional relapse treatment. However, any alloBMT relapse beyond second remission should be transplanted with allogeneic stem cells (bone marrow or peripheral stem cells). In particular, family mismatched donors or matched unrelated donors may be acceptable in high-risk cases beyond first remission. In contrast, ASCR in ALL seems not to be superior to conventional therapy. In AML the standard-risk patient, defined by criteria such as FAB M1/M2-Auer rods positive, all FAB M3, and FAB M4, is not a candidate for SCT in first remission. Patients presenting other criteria or more than 5% of blasts in the bone marrow at day 15 are at high risk in first remission and should be considered for allo BMT if a family matched donor is available. ASCR in first remission AML remains a controversial issue. In contrast, in second remission alloBMT as well as ASCR are superior to conventional chemotherapy.

The contribution of animal models to the development of treatments for hematologic recovery following myeloablative therapy: a review

This review describes the role that animal models have played in the development of clinical procedures for growth factor and hematopoietic cell therapies following high-dose cancer chemotherapy, radiotherapy or both. Data are discussed describing animal models that add to the understanding of human hematopoiesis, including myeloid and lymphoid lineage localization and in vivo maturation. Finally, current animal models of cytokine and cell therapies are presented in the context of their contributions to early clinical trials and future therapies. These studies underscore the past and current contributions animal investigations have made to improving clinical therapies.

Efficacy and toxicity of radiation in preparative regimens for pediatric stem cell transplantation. II: Deleterious consequences

There has been a dramatic improvement in the treatment of both allogeneic and autologous stem cell transplants, especially in children and young adults. However, attempts to apply more intensive conditioning treatments to the more refractory pediatric malignancies have also increased the risks of deleterious consequences. This review examines the risks, and reports important variations in the toxic effects of using different conditioning techniques.

Efficacy and toxicity of radiation in preparative regimens for pediatric stem cell transplantation. I: Clinical applications and therapeutic effects

Here, we review the role of total body irradiation in the treatment of children with bone marrow transplantation, as well as alternative sources of stem cells. We were unable to demonstrate any clear superiority of TBI-containing preparative regimens, but we were able to find a few definitive reports of significantly enhanced toxicity or important variations in control of the underlying primary diseases, in comparing TBI-based regimens, with those containing only chemotherapy.