Results of a randomized trial in children with Acute Myeloid Leukaemia: medical research council AML12 trial.

The Medical Research Council Acute Myeloid Leukaemia 12 (MRC AML12) trial (children) addressed the optimal anthracenedione/anthracycline in induction and the optimal number of courses of consolidation chemotherapy. 504 children (<16 years) with AML were randomized between mitoxantrone/cytarabine/etoposide or daunorubicin/cytarabine/etoposide as induction chemotherapy and 270 entered a second randomization between a total of four or five courses of treatment. Ten-year event-free (EFS) and overall survival (OS) was 54% and 63% respectively; the relapse rate was 35%. There was no difference in complete remission rate between the induction regimens, but there was a benefit for mitoxantrone with regard to relapse rate [32% vs. 39%; Hazard ratio (HR) 0·73; 95% confidence interval (CI) 0·54, 1·00] and disease-free survival (DFS; 63% vs. 55%; HR 0·72; 95% CI 0·54, 0·96). However, this did not translate into a better EFS or OS (HR 0·84; 95% CI 0·63, 1·12). Results of the second randomization did not show a survival benefit for a fifth course of treatment (HR 1·01; 95% CI 0·63, 1·62), suggesting a ceiling of benefit for conventional chemotherapy and demonstrating the need for new agents. EFS was superior compared to the preceding trial AML10, partly due to fewer deaths in remission, highlighting the importance of supportive care.

Cytogenetics of childhood acute myeloid leukemia: United Kingdom Medical Research Council Treatment trials AML 10 and 12.

PURPOSE: Karyotype is an independent indicator of prognosis in acute myeloid leukemia (AML) that is widely applied to risk-adapted therapy. Because AML is rare in children, the true prognostic significance of individual chromosomal abnormalities in this age group remains unclear. PATIENTS AND METHODS: This cytogenetic study of 729 childhood patients classified them into 22 subgroups and evaluated their incidence and risk. RESULTS: Rearrangements of 11q23 were the most frequent abnormality found in approximately 16% of patients, with 50% of these in infants. The outcome for all patients with 11q23 abnormalities was intermediate; no difference was observed for those with t(9;11)(p21-22;q23). The core binding factor leukemias with the translocations t(8;21)(q22;q22) and inv(16)(p13q22) occurred at incidences of 14% and 7%, respectively, predominantly in older children, and their prognosis was favorable. An adverse outcome was observed in patients with monosomy 7, abnormalities of 5q, and t(6;9)(p23;q34). Abnormalities of 3q and complex karyotypes, in the absence of favorable-risk features, have been associated with an adverse outcome in adults, but the results were not significant in this childhood series. However, the presence of 12p abnormalities predicted a poor outcome. CONCLUSION: Because the spectrum of chromosomal changes and their risk association seem to differ between children and adults with AML, biologic differences are emerging, which will contribute to the redefinition of risk stratification for different age groups in the future.

Low frequency of MLL-partial tandem duplications in paediatric acute myeloid leukaemia using MLPA as a novel DNA screenings technique.

Mixed-lineage leukaemia (MLL)-partial tandem duplications (PTDs) are found in 3-5% of adult acute myeloid leukaemia (AML), and are associated with poor prognosis. In adult AML, MLL-PTD is only detected in patients with trisomy 11 or internal tandem duplications of FLT3 (FLT3-ITD). To date, studies in paediatric AML are scarce, and reported large differences in the frequency of MLL-PTD, frequently utilising mRNA RT-PCR only to detect MLL-PTDs. We studied the frequency of MLL-PTD in a large cohort of paediatric AML (n=276) and the results from two different methods, i.e. mRNA RT-PCR, and multiplex ligation-dependent probe amplification (MLPA), a method designed to detect copy number differences of specific DNA sequences. In some patients with an MLL-rearrangement, MLL-PTD transcripts were detected, but were not confirmed by DNA-MLPA, indicating that DNA-MLPA can more accurately detect MLL-PTD compared to mRNA RT-PCR. In paediatric AML, MLL-PTD was detected in 7/276 patients (2.5%). One case had a trisomy 11, while the others had normal cytogenetics. Furthermore 4 of the 7 patients revealed a FLT3-ITD, which was significantly higher compared with the other AML cases (p=0.016). In conclusion, using DNA-MLPA as a novel screenings technique in combination with mRNA RT-PCR a low frequency of MLL-PTD in paediatric AML was found. Larger prospective studies are needed to further define the prognostic relevance of MLL-PTD in paediatric AML.

Clinical relevance of Wilms tumor 1 gene mutations in childhood acute myeloid leukemia.

Wilms tumor 1 (WT1) mutations have recently been identified in approximately 10% of adult acute myeloid leukemia (AML) with normal cytogenetics (CN-AML) and are associated with poor outcome. Using array-based comparative genome hybridization in pediatric CN-AML samples, we detected a WT1 deletion in one sample. The other WT1 allele was mutated. This prompted us to further investigate the role of WT1 aberrations in childhood AML. Mutations were found in 35 of 298 (12%) diagnostic pediatric AML samples. In 19 of 35 (54%) samples, more than one WT1 aberration was found: 15 samples had 2 different mutations, 2 had a homozygous mutation, and 2 had a mutation plus a WT1 deletion. WT1 mutations clustered significantly in the CN-AML subgroup (22%; P < .001) and were associated with FLT3/ITD (43 vs 17%; P < .001). WT1 mutations conferred an independent poor prognostic significance (WT1 mutated vs wild-type patients: 5-year probability of overall survival [pOS] 35% vs 66%, P = .002; probability of event-free survival 22% vs 46%, P < .001; and cumulative incidence of relapse or regression 70% vs 44%, P < .001). Patients with both a WT1 mutation and a FLT3/ITD had a dismal prognosis (5-year pOS 21%). WT1 mutations occur at a significant rate in childhood AML and are a novel independent poor prognostic marker.

Vincristine pharmacokinetics in children with Down syndrome.

Children with Down syndrome (DS), who represent about 2% of childhood acute lymphoblastic leukemia, have inferior prognosis compared to non-DS children. For vincristine (and many other anticancer agents) pharmacokinetic data are scant or missing, and there is considerable uncertainty about the optimal dosing of drugs to patients with DS. We studied vincristine pharmacokinetics on treatment day one in six children with DS and compared to 92 non-DS children. No differences were found. Thus, we found no rationale for dose reduction of vincristine in DS children from a strictly pharmacokinetic point of view.

Vincristine pharmacokinetics is related to clinical outcome in children with standard risk acute lymphoblastic leukemia.

Vincristine is a key drug in the treatment of childhood and adult acute lymphoblastic leukemia (ALL), and many other childhood malignancies. Despite decades of wide clinical use, no data on the correlation between vincristine pharmacokinetics and long-term clinical outcome have been published. We here report clinical data (median follow-up time 10.5 years, range 7.3-12 years) for 86 children with B-cell precursor ALL, in whom vincristine kinetics were studied on treatment day 1. The median total plasma clearance was 429 and 331 ml/min per m(2) and the area under the plasma concentration-time curve (AUC) was 4.49 and 5.40 mg/l x min in relapse and non-relapse patients, respectively (not significant). In standard risk patients, where treatment depends more heavily on vincristine than in other subgroups, the relative risk (RR) of relapse was significantly increased for patients with clearance values above median (RR 5.2; P = 0.036), or AUC values below median (RR 5.8; P = 0.025). Our data suggest a relationship between the antileukemic effect and the systemic exposure of the drug, which warrants further studies.

Prognostic significance of blasts in the cerebrospinal fluid without pleiocytosis or a traumatic lumbar puncture in children with acute lymphoblastic leukemia: experience of the Dutch Childhood Oncology Group.

PURPOSE: To determine the significance of blasts in the CSF without pleiocytosis and a traumatic lumbar puncture in children with acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: We retrospectively studied a cohort of 526 patients treated in accordance with the virtually identical Dutch protocols ALL-7 and ALL-8. Patients were classified into five groups: CNS1, no blasts in the CSF cytospin; CNS2, blasts present in the cytospin, but leukocytes less than 5/microL; CNS3, blasts present and leukocytes more than 5/microL. Patients with a traumatic lumbar puncture (TLP; > 10 erythrocytes/mL) were classified as TLP+ (blasts present in the cytospin) or TLP- (no blasts). RESULTS: Median duration of follow-up was 13.2 years (range, 6.9 to 15.5 years). Event-free survival (EFS) was 72.6% (SE, 2.5%) for CNS1 patients (n = 304), 70.3% (SE, 4.7%) for CNS2 patients (n = 111), and 66.7% (SE, 19%) for CNS3 patients (n = 10; no significant difference in EFS between the groups). EFS was 58% (SE, 7.6%) for TLP+ patients (n = 62) and 82% (SE, 5.2%) for TLP- patients (n = 39; P < .01). Cox regression analysis identified TLP+ status as an independent prognostic factor (risk ratio, 3.5; 95% CI, 1.4 to 8.8; P = .007). Cumulative incidence of CNS relapses was 0.05 and 0.07 in CNS1 and CNS2 patients, respectively (not statistically significant). CONCLUSION: In our experience, the presence of a low number of blasts in the CSF without pleiocytosis has no prognostic significance. In contrast, a traumatic lumbar puncture with blasts in the CSF specimen is associated with an inferior outcome.

Treatment for myeloid leukaemia of Down syndrome: population-based experience in the UK and results from the Medical Research Council AML 10 and AML 12 trials.

Down syndrome (DS) children are at an increased risk of developing myelodysplasia and acute myeloid leukaemia (AML). We retrospectively analysed the population-based data on 81 children with myeloid leukaemia of Down syndrome (ML-DS) from the UK National Registry of Childhood Tumours and experience in the Medical Research Council (MRC) AML 10 and AML 12 trials, which enrolled 46 children with ML-DS from 1988 to 2002. Eight per cent of UK children with AML had DS, but DS children comprised only 5% of children registered in MRC trials. The unique clinical characteristics of ML-DS were confirmed. Overall survival (OS) of ML-DS at 5 years increased from 47% in UK children diagnosed from 1988 to 1995 to 75% in children diagnosed from 1996 to 2002. OS for DS children registered in AML 10 and AML 12 was 74% in 5 years and improved from AML 10 to AML 12 (56% vs. 83%) There was no significant difference in OS between DS and non-DS children (OS: 74% vs. 62%, P = 0.4) in the trials, but this result masked a significant increase in early death amongst DS children, with a significant reduction in mortality later on. Relapse was significantly reduced (3% vs. 39%, P = 0.0003), leading to the improved disease-free survival (83% vs. 56%, P = 0.02). Given the increased number of early treatment-related deaths, future treatment protocols should aim to reduce chemotherapy dosage or intensity whilst maintaining low rates of resistant and recurrent disease.

Increasing the dosage of vincristine: a clinical and pharmacokinetic study of continuous-infusion vincristine in children with central nervous system tumors.

BACKGROUND: Vincristine (VCR) is widely used to treat patients with malignant disease; among the patients treated with VCR are children with brain tumors. In vitro studies have demonstrated that the cytotoxic activity of VCR is related to both extracellular concentration and duration of exposure. The attainment of higher plasma concentrations by injecting larger bolus doses of VCR has been limited by concerns about neurotoxicity. One possible alternative strategy for enhancing the antitumor efficacy of VCR involves prolonging the duration of in vivo exposure. Therefore, the authors explored the neurotoxicity and pharmacokinetics of VCR administered via a 96-hour continuous infusion after administration of a conventional bolus dose in a pediatric population. METHODS: The current study included 16 patients, 11 of whom were males. The median age of the study population was 4.8 years (range, 1.7-15.8 years). The diagnoses included intrinsic pontine glioma (n = 4), ependymoma (n = 5), astrocytoma (n = 3), medulloblastoma/primitive neuroectodermal tumor (PNET; n = 2), ganglioglioma (n = 1), and choroid plexus carcinoma (n = 1). Of the 16 patients, 5 were newly diagnosed, and the remaining 11 had disease recurrences, 8 of which arose after radiotherapy. Treatment included cyclophosphamide 65 mg/kg administered intravenously over 1 hour on Day 1, a bolus of VCR 1.5 mg/m(2) administered intravenously on Day 2, and VCR 0.5 mg/m(2) per 24 hours administered via continuous intravenous infusion on Days 2-5. Thus, a total VCR dose of 3.5 mg/m(2) was administered via infusion over 4 days. Fifteen patients received 2 courses of treatment at 21-28-day intervals, and a total of 31 treatment courses were administered. VCR concentrations in plasma samples were measured using high-performance liquid chromatography. RESULTS: Jaw pain, constipation, mild abdominal pain, and depressed reflexes were common. However, only 1 of 31 courses was associated with Grade III toxicity, and no Grade IV toxicity (e.g., cranial nerve palsy, ileus, inappropriate antidiuretic hormone secretion, seizures, hallucinations, etc.) was noted. The steady-state plasma concentration of VCR during continuous infusion ranged from 1 to 3 microg/L in all patients. Responses after 2 courses were evaluated in 14 of 16 patients. A complete response was noted in one patient (astrocytoma), a partial response in three patients (one each with astrocytoma, ependymoma, and PNET), stable disease in seven patients, and disease progression in three patients. CONCLUSIONS: Continuous infusion of VCR after a conventional bolus dose plus cyclophosphamide for children with tumors of the central nervous system did not result in significant neurotoxicity and appeared to be a safe strategy for achieving increased systemic exposure.

Predictive value of clinical evaluation in the follow-up of children with a brain tumor.

BACKGROUND: During follow-up of children with a brain tumor, traditionally surveillance-imaging studies are done in addition to clinical evaluations. The purpose of this study was to determine the role of clinical evaluations by a multidisciplinary team for the detection of recurrent tumor. PROCEDURE: We retrospectively assessed the predictive value of clinical evaluation, using subsequent neuroimaging as the gold standard. Ninety-eight children with a newly diagnosed primary brain tumor were included in the study. In these patients, 393 imaging studies were done, 75 because of clinical suspicion of recurrence, and 318 for routine surveillance only. RESULTS: In 28 of these 75 imaging studies on clinical indications, a radiologic diagnosis of recurrence was made. Only 9 out of 318 routine surveillance imaging studies resulted in an unexpected diagnosis of recurrence. Thus, the overall positive predictive value of clinical evaluation was 37%; the overall negative predictive value was 97%. The negative predictive values for specific brain tumors varied from 91% (optical glioma) to 99% (primitive neuroectodermal tumors). CONCLUSIONS: An accurate multidisciplinary clinical evaluation has a very high negative predictive value. Consequently, the added value of surveillance imaging studies is limited. The role of such studies during the follow-up of children with brain tumors should be reconsidered.

Cerebrospinal fluid concentrations of vincristine after bolus intravenous dosing: a surrogate marker of brain penetration.

BACKGROUND: Vincristine (VCR) is used widely in oncology practice, and regular dosing is commonly associated with the development of sensorimotor or autonomic neuropathies. However, the incidence of VCR-related central nervous system (CNS) toxicity is comparatively low, suggesting that the blood-brain barrier may limit drug penetration into the brain parenchyma. This study determined whether measurable concentrations of VCR could be detected in the cerebrospinal fluid (CSF), as a surrogate marker of brain parenchyma penetration, after bolus intravenous injection in children without primary CNS pathology. METHODS: The authors studied 17 pediatric patients ages 2.5-14.1 years (median, 6.8 years) with acute lymphoblastic leukemia or non-Hodgkin lymphoma without evidence of leptomeningeal disease. Patients received VCR 1.5 mg/m2 by intravenous bolus injection followed at varying intervals by lumbar puncture for scheduled intrathecal methotrexate administration under general anesthesia. Paired VCR concentrations in both plasma and CSF were measured in each patient simultaneously at times ranging from 8 minutes to 146 minutes after the VCR injection. Three patients were studied twice. The paired samples were stored at -40 degrees C until analysis using a high performance liquid chromatography assay with a sensitivity of 0.1 microg/L in CSF and 0.4 microg/L in plasma. RESULTS: Plasma VCR concentrations ranged from 2.2 microg/L to 91.2 microg/L. No measurable VCR concentrations were detected in the CSF samples. CONCLUSIONS: Measurable concentrations of VCR in CSF are not achieved after the administration of standard intravenous bolus doses of VCR. The current observations are consistent with the relative rarity of VCR-related CNS neurotoxicity compared with the commonly observed sensorimotor and autonomic neuropathies. These findings suggest that the penetration of VCR into the brain parenchyma of patients with a relatively intact blood-brain barrier is low and that VCR may have a limited role in the CNS-directed therapy of these patients.