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2.  Cognitive Outcomes Following Contemporary Treatment Without Cranial Irradiation for Childhood Acute Lymphoblastic Leukemia 
Background
Treatment of acute lymphoblastic leukemia (ALL) has included the use of prophylactic cranial irradiation in up to 20% of children with high-risk disease despite known cognitive risks of this treatment modality.
Methods
Patients enrolled on the St Jude ALL Total Therapy Study XV, which omitted prophylactic cranial irradiation in all patients, were assessed 120 weeks after completion of consolidation therapy (n = 243) using a comprehensive cognitive battery. χ2 analysis was used to compare the percentage of below-average performers among the entire ALL patient group to the expected rate based on the normative sample. Univariate logistic regression was used to estimate the effect of intensity of chemotherapy (treatment arm), age at diagnosis, and sex on the probability of below-average performance. All statistical tests were two-sided.
Results
Overall, the ALL group had a statistically significantly higher risk for below-average performance on a measure of sustained attention (67.31% more than 1 SD below the normative mean for omission errors, P < .001) but not on measures of intellectual functioning, academic skills, or memory. Patients given higher intensity chemotherapy were at greater risk for below-average performance compared with those given lower intensity therapy on measures of processing speed (27.14% vs 6.25%, P = .009) and academic abilities (Math Reasoning: 18.60% vs 3.90%, P = .008; Word Reading: 20.00% vs 2.60%, P = .007; Spelling: 27.91% vs 3.90%, P = .001) and had higher parent-reported hyperactivity (23.00% vs 9.84%, P = .018) and learning problems (35.00% vs 16.39%, P = .005). Neither age at diagnosis nor sex was associated with risk for below-average cognitive performance.
Conclusions
Omitting cranial irradiation may help preserve global cognitive abilities, but treatment with chemotherapy alone is not without risks. Caregiver education and development of interventions should address both early attention deficits and cognitive late effects.
doi:10.1093/jnci/djs344
PMCID: PMC3529594  PMID: 22927505
3.  Risk-adapted donor lymphocyte infusion based on chimerism and donor source in pediatric leukemia 
Blood Cancer Journal  2013;3(8):e137-.
Donor lymphocyte infusion (DLI) is commonly used to treat leukemia relapse following stem cell transplantation. In florid relapse, however, the efficacy of DLI is limited with substantial risk of severe graft-versus-host disease (GvHD). Here, we develop a novel risk-adapted strategy characterized by pre-emptive DLI initiated at the time of mixed chimerism, a small starting dose based on donor source, dose-escalation guided by real-time chimerism monitoring and withholding of DLI immediately in patients achieving full donor chimerism. A total of 178 DLIs were given to 38 patients with mixed chimerism; thereafter, 33 patients (86.8%) had donor chimerism successfully increased, including 30 (78.9%) who had chimerism fully converted back to 100% donor. Cumulative incidence of relapse was significantly lower (P=0.00004) and overall survival higher (P=0.0003) in patients with chimerism fully corrected as compared with those of patients whose chimerism remained mixed. Only 13.2% of the patients developed acute grade III-IV GvHD with no associated mortality. In conclusion, the risk-adapted DLI strategy is useful in minimizing the risk of childhood leukemia relapse, GvHD and death.
doi:10.1038/bcj.2013.39
PMCID: PMC3763390  PMID: 23995046
donor lymphocyte infusion; leukemia; mixed chimerism; transplantation
5.  Clinical Pharmacogenetics Implementation Consortium Guidelines for Thiopurine Methyltransferase Genotype and Thiopurine Dosing 
Thiopurine methyltransferase (TPM T) activity exhibits monogenic co-dominant inheritance, with ethnic differences in the frequency of occurrence of variant alleles. With conventional thiopurine doses, homozygous TPMT-deficient patients (~1 in 178 to 1 in 3,736 individuals with two nonfunctional TPMT alleles) experience severe myelosuppression, 30–60% of individuals who are heterozygotes (~3–14% of the population) show moderate toxicity, and homozygous wildtype individuals (~86–97% of the population) show lower active thioguanine nucleolides and less myelosuppression. We provide dosing recommendations (updates at http://www.pharmgkb.org) for azathioprine, mercaptopurine (MP), and thioguanine based on TPMT genotype.
doi:10.1038/clpt.2010.320
PMCID: PMC3098761  PMID: 21270794
6.  Clinical Pharmacogenetics Implementation Consortium Guidelines for Thiopurine Methyltransferase Genotype and Thiopurine Dosing 
Thiopurine methyltransferase (TPM T) activity exhibits monogenic co-dominant inheritance, with ethnic differences in the frequency of occurrence of variant alleles. With conventional thiopurine doses, homozygous TPMT-deficient patients (~1 in 178 to 1 in 3,736 individuals with two nonfunctional TPMT alleles) experience severe myelosuppression, 30–60% of individuals who are heterozygotes (~3–14% of the population) show moderate toxicity, and homozygous wildtype individuals (~86–97% of the population) show lower active thioguanine nucleolides and less myelosuppression. We provide dosing recommendations (updates at http://www.pharmgkb.org) for azathioprine, mercaptopurine (MP), and thioguanine based on TPMT genotype.
doi:10.1038/clpt.2010.320
PMCID: PMC3098761  PMID: 21270794
7.  Efficacy of high-dose methotrexate, ifosfamide, etoposide and dexamethasone salvage therapy for recurrent or refractory childhood malignant lymphoma 
Annals of Oncology  2010;22(2):468-471.
Background: Children with recurrent or refractory malignant lymphoma generally have a poor prognosis. There is a need for new active drug combinations for this high-risk group of patients.
Patients and methods: This study evaluated the activity and toxicity of the methotrexate, ifosfamide, etoposide and dexamethasone (MIED) regimen for childhood refractory/recurrent non-Hodgkin’s lymphoma (NHL) or Hodgkin’s lymphoma (HL). From 1991 through 2006, 62 children with refractory/recurrent NHL (n = 24) or HL (n = 38) received one to six cycles of MIED. Based on MIED response, intensification with hematopoietic stem cell transplantation (HSCT) was considered.
Results: There were 10 complete (CR) and 5 partial responses (PR) among the 24 children with NHL [combined response rate, 63%; 95% confidence interval (CI) 38% to 73%]. There were 13 CR and 18 PR among the 37 assessable children with HL (combined response rate, 84%; 95% CI, 68% to 94%). Although 59% courses were associated with grade IV neutropenia, treatment was well tolerated and without toxic deaths.
Conclusions: MIED is an effective regimen for refractory/recurrent childhood malignant lymphoma, permitting a bridge to intensification therapy with HSCT.
doi:10.1093/annonc/mdq348
PMCID: PMC3030464  PMID: 20624787
childhood; lymphoma; recurrent; refractory
8.  Promoter polymorphisms in the beta-2 adrenergic receptor are associated with drug-induced gene expression changes and response in acute lymphoblastic leukemia 
We investigated whether genetic polymorphisms in the promoter region of the pro-apoptotic beta-2 adrenergic receptor gene (ADRB2) influence treatment-induced changes in ADRB2 expression in leukemia cells and response to chemotherapy. The ADRB2 promoter region was genotyped in germline DNA from 369 children with acute lymphoblastic leukemia (ALL). For 95 patients, sufficient RNA was available before and after in vivo treatment to assess treatment-induced gene expression changes in ALL cells. After treatment, the median ADRB2 mRNA expression was 9-fold lower in leukemia cells of patients who ultimately relapsed compared to patients who remained in continuous complete remission. Polymorphisms in the ADRB2 promoter were significantly linked to methotrexate induced up-regulation in ADRB2 gene expression in ALL cells. Moreover, the ADRB2 promoter haplotype was significantly related to early treatment response in 245 uniformly treated children with ALL. We conclude that germline polymorphisms in ADRB2 are linked to the antileukemic effects of ALL chemotherapy.
doi:10.1038/clpt.2010.212
PMCID: PMC3105596  PMID: 20981007
pharmacogenetics; promoter gene polymorphism; treatment-induced gene expression changes
9.  Long-term results of St. Jude Total Therapy studies 11, 12, 13A, 13B and 14 for childhood acute lymphoblastic leukemia 
We analyzed the long-term outcome of 1011 patients treated in five successive clinical trials (Total Therapy Studies 11, 12, 13A, 13B and 14) between 1984 and 1999. The event-free survival improved significantly (p=0.003) from the first two trials conducted in the 1980s to the three more recent trials conducted in the 1990s. Approximately 75% of patients treated in the 1980s and 80% in the 1990s were cured. Early intensive triple intrathecal therapy, together with more effective systemic therapy, including consolidation and reinduction treatment (Studies 13A and 13B) as well as dexamethasone (Study 13A), resulted in a very low rate of isolated central-nervous-system relapse rate (<2%), despite the reduced use of cranial irradiation. Factors consistently associated with treatment outcome were age, leukocyte count, immunophenotype, DNA index, and minimal residual disease level after remission induction treatment. Because of concerns about therapy-related secondary myeloid leukemia and brain tumors, in our current trials we reserve the use of etoposide for patients with refractory or relapsed leukemia undergoing hematopoietic stem cell transplantation, and cranial irradiation for those with CNS relapse. The next main challenge is to further increase cure rates while improving quality of life for all patients.
doi:10.1038/leu.2009.252
PMCID: PMC2820159  PMID: 20010620
B-lineage ALL; T-lineage ALL; CNS relapse; prognostic factors; leukemia; chemotherapy
10.  Comparison of native E. coli and PEG asparaginase pharmacokinetics and pharmacodynamics in pediatric acute lymphoblastic leukemia 
Asparaginase is used routinely in frontline clinical trials for the treatment of childhood acute lymphoblastic leukemia (ALL). The goals of this study were to assess the pharmacokinetics and pharmacodynamics of asparaginase and to mathematically model the dynamics between asparaginase and asparagine in relapsed ALL. Forty children were randomized to receive either native or PEGylated (PEG) Escherichia coli asparaginase during reinduction therapy. Serial plasma asparaginase and asparagine, cerebrospinal fluid (CSF) asparagine, and serum anti-asparaginase antibody samples were collected. The asparaginase clearance was higher (P=.001) for native vs. PEG asparaginase. Patients with antibodies to PEG asparaginase had faster PEG clearance (P=.004) than antibody-negative patients. Patients who were positive for antibodies had higher CSF asparagine than those who were negative (P=.04). The modeling suggests that by modifying dosages, comparable asparagine depletion should be achievable with both preparations. At relapse, there were significant pharmacokinetic and pharmacodynamic differences due to asparaginase preparation and antibody status.
doi:10.1038/clpt.2009.162
PMCID: PMC2831746  PMID: 19741605
11.  Genetic Polymorphism of Inosine Triphosphate Pyrophosphatase Is a Determinant of Mercaptopurine Metabolism and Toxicity During Treatment for Acute Lymphoblastic Leukemia 
The influence of genetic polymorphism in inosine triphosphate pyrophosphatase (ITPA) on thiopurine-induced adverse events has not been investigated in the context of combination chemotherapy for acute lymphoblastic leukemia (ALL). This study investigated the effects of a common ITPA variant allele (rs41320251) on mercaptopurine metabolism and toxicity during treatment of children with ALL. Significantly higher concentrations of methyl mercaptopurine nucleotides were found in patients with the nonfunctional ITPA allele. Moreover, there was a significantly higher probability of severe febrile neutropenia in patients with a variant ITPA allele among patients whose dose of mercaptopurine had been adjusted for TPMT genotype. In a cohort of patients whose mercaptopurine dose was not adjusted for TPMT phenotype, the TPMT genotype had a greater effect than the ITPA genotype. In conclusion, genetic polymorphism of ITPA is a significant determinant of mercaptopurine metabolism and of severe febrile neutropenia, after combination chemotherapy for ALL in which mercaptopurine doses are individualized on the basis of TPMT genotype.
doi:10.1038/clpt.2008.154
PMCID: PMC2762405  PMID: 18685564
12.  Stroma-supported culture in childhood B-lineage acute lymphoblastic leukemia cells predicts treatment outcome. 
Journal of Clinical Investigation  1996;97(3):755-760.
We developed a stroma cell culture system that suppresses apoptosis of malignant cells from cases of B-lineage acute lymphoblastic leukemia. By multiparameter flow cytometric measurements of cell recovery after culture on stromal layers, we assessed the growth potential of 70 cases of newly diagnosed B-lineage acute lymphoblastic leukemia and related the findings of treatment outcome in a single program of chemotherapy. The numbers of leukemic cells recovered after 7 d of culture ranged from < 1 to 292% (median, 91%). The basis of poor cell recoveries from stromal layers appeared to be a propensity of the lymphoblasts to undergo apoptosis. The probability of event-free survival at 4 yr of follow-up was 50 +/- 9% (SE) among patients with higher cell recoveries ( > 91%), and 94 +/- 6% among those with reduced cell recoveries (+/- 91%; P = 0.0003). The prognostic value of leukemic cell recovery after culture exceeded estimates for all other recognized high-risk features and remained the most significant after adjustment with all competing covariates. Thus, the survival ability of leukemic cells on bone marrow-derived stromal layers reflects aggressiveness of the disease and is a powerful, independent predictor of treatment outcome in children with B-lineage acute lymphoblastic leukemia.
PMCID: PMC507113  PMID: 8609232
13.  Accumulation of methotrexate polyglutamates in lymphoblasts is a determinant of antileukemic effects in vivo. A rationale for high-dose methotrexate. 
Methotrexate (MTX) is one of the most widely used drugs for the treatment of childhood acute lymphoblastic leukemia (ALL) and is commonly given in high doses. However, the rationale for high-dose MTX (HDMTX) has been challenged recently. To determine whether higher MTX polyglutamate (MTXPG) concentrations in ALL blasts translate into greater antileukemic effects, 150 children with newly diagnosed ALL were randomized to initial treatment with either HDMTX (1,000 mg/m2 intravenously over 24 h) or lower-dose MTX (30 mg/m2 by mouth every 6 h x 6). ALL blasts accumulated higher concentrations of MTXPG and long-chain MTXPG (MTXPGLC) after HDMTX (P < 0.00001). Of 101 patients evaluable for peripheral blast cytoreduction, MTXPG concentrations were higher in patients whose blast count decreased within 24 h (P = 0.005) and in those who had no detectable circulating blasts within 4 days (P = 0.004). The extent of inhibition of de novo purine synthesis in ALL blasts was significantly related to the blast concentration of MTXPGLC (IC95% = 483 pmol/10(9) blasts). The percentage of patients with 44-h MTXPGLC exceeding the IC95% was greater after HDMTX (81%) than LDMTX (46%, P < 0.0001). These data indicate that higher blast concentrations of MTXPG are associated with greater antileukemic effects, establishing a strong rationale for HD-MTX in the treatment of childhood ALL.
PMCID: PMC507064  PMID: 8550853
14.  Height at diagnosis of malignancies. 
Archives of Disease in Childhood  1987;62(5):495-499.
Studies of the presenting height of children with malignancies have produced conflicting results, from an excess of taller patients to an excess of shorter patients. The problems of measurement bias, inadequate comparison populations, small numbers of patients, subgroup analyses, and overreliance on simple significance tests are all possible reasons for the variation in results. To clarify this issue, we studied heights at diagnosis of 3657 children and adolescents aged under 18 years. Their malignancies included acute lymphoblastic leukaemia, non-Hodgkin's lymphoma, Hodgkin's disease, acute non-lymphoblastic leukaemia, osteosarcoma, retinoblastoma, neuroblastoma, Wilms' tumour, rhabdomyosarcoma, and Ewing's sarcoma. Compared with published standards for the heights of children in control populations, no significant deviation from population norms was found for patients in any of the 10 disease categories after proper adjustment for multiple significance testing.
PMCID: PMC1778389  PMID: 3606184
15.  Blast cell methotrexate-polyglutamate accumulation in vivo differs by lineage, ploidy, and methotrexate dose in acute lymphoblastic leukemia. 
Journal of Clinical Investigation  1994;94(5):1996-2001.
High-dose methotrexate (HDMTX) is a component of most treatment protocols for childhood acute lymphoblastic leukemia (ALL), yet recent studies of receptor-mediated transport and saturable polyglutamylation have questioned its rationale. To investigate this in vivo, methotrexate and its active polyglutamated metabolites (MTX-PG) were measured in bone marrow blasts obtained from 101 children randomized to single-agent therapy with either HDMTX (1 g/m2 per 24 h i.v., n = 47) or low-dose MTX (LDMTX, 30 mg/m2 by mouth every 6 h x 6, n = 54), before remission induction therapy. Blast concentrations of total MTX-PGs (median 460 vs 1380 pmol/10(9) cells) and of long-chain MTX-glu4-6 were both significantly higher after HDMTX (P < 0.001). With either treatment, MTX-PGs were significantly higher in B-lineage blasts than in T-lineage blasts (LDMTX P = 0.001, HDMTX P = 0.03). In a multiple regression analysis of B-lineage ALL, blast MTX-PG was significantly related to MTX dose (or plasma MTX concentration), lymphoblast ploidy (hyperdiploid > nonhyperdiploid), and percentage S-phase. This is the first evidence that HDMTX achieves higher MTX-PG concentrations in ALL blasts in vivo, establishing a rationale for HDMTX in the treatment of childhood ALL, especially T-lineage or nonhyperdiploid B-lineage ALL, disease characteristics associated with a poor prognosis on conventional therapy.
Images
PMCID: PMC294625  PMID: 7525652
16.  Clonal analysis of childhood acute lymphoblastic leukemia with "cytogenetically independent" cell populations. 
Journal of Clinical Investigation  1989;83(6):1971-1977.
Acute lymphoblastic leukemia (ALL) is generally regarded as a clonal disease in which a single abnormal progenitor cell gives rise to neoplastic progeny. Five of 463 cases of childhood ALL with adequately banded leukemic cells were found to have two cytogenetically independent cell populations. In addition, two of the four cases tested had more than two rearranged immunoglobulin genes and (or) T cell receptor genes. To investigate the clonality of these unusual leukemias, we examined the neoplastic cells for X-linked markers extrinsic to the disease. Leukemic cells from each of the three patients heterozygous for an X-linked, restriction fragment length polymorphism showed a single active parental allele, suggesting that both apparently independent cell populations developed from a common progenitor. These cases provide evidence that leukemogenesis involves a multistep process of mutation and suggest that karyotypic abnormalities may be a late event of malignant transformation.
Images
PMCID: PMC303920  PMID: 2566623

Results 1-16 (16)