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Ching-Hon Pui

Publications and source records attributed to Ching-Hon Pui.

At least 91 records · Page 5Linked to original sources
PubMed2003

Results of therapy for acute lymphoblastic leukemia in black and white children.

CONTEXT: Treatment results for acute lymphoblastic leukemia (ALL) clearly have improved over the past decade, but black children have not fared as well as white children in large national trials. OBJECTIVE: To compare the clinical outcomes of therapy for black and white children with ALL treated at a single institution. DESIGN, SETTING, AND PATIENTS: A retrospective analysis of 412 children and adolescents (68 black, 338 white, and 6 other race) with newly diagnosed ALL who were treated consecutively at a pediatric cancer center in Memphis, Tenn. Patients were enrolled from December 1991 to July 1998 in successive Total Therapy studies regardless of race, ethnicity, or ability to pay and received risk-directed therapy according to stringent criteria. INTERVENTIONS: All patients received the same intensive, remission-induction therapy followed by 120 weeks of risk-assigned postremission therapy that included reinduction treatment, pulses of high-dose methotrexate, and early intensification of intrathecal chemotherapy. MAIN OUTCOME MEASURES: Event-free and overall survival rates for black and white children were estimated by the method of Kaplan and Meier and compared with the Mantel-Haenszel test and by Cox proportional hazards regression analysis, adjusting for known prognostic factors. RESULTS: The 68 black children were significantly more likely than the 338 white children to have higher-risk prognostic features, including an initial leukocyte count greater than 100 x 10(3)/ microL, a T-cell immunophenotype, and the t(1;19) chromosomal translocation with E2A-PBX1 fusion, and were less likely to have hyperdiploid blast cells, a favorable prognostic factor in childhood ALL. However, the clinical outcomes for these 2 cohorts were not significantly different: 5-year event-free and overall survival rates were 80.7% (95% confidence interval [CI], 70.3%-91.1%) and 86.2% (95% CI, 77.2%-95.2%) for black children vs 79.4% (95% CI, 74.7%-84.1%) and 85.0% (95% CI, 80.9%-89.1%) for white children. Ten-year results also were comparable, but the CIs were wide because of the small numbers of patients who had been followed up for 10 years or more. The lack of a racial effect on the long-term outcome of therapy was still apparent in a multivariate Cox regression analysis, adjusting for sex, age, presenting leukocyte count, leukemic cell DNA index, immunophenotype, and central nervous system status. CONCLUSION: With equal access to effective antileukemic therapy, black and white children with ALL can expect the same high rate of cure.

Adolescent↗
PubMed2003

Effects of prednisone and genetic polymorphisms on etoposide disposition in children with acute lymphoblastic leukemia.

Etoposide is a substrate for P-glycoprotein, CYP3A4, CYP3A5, and UGT1A1. Glucocorticoids modulate CYP3A and P-glycoprotein in preclinical models, but their effect on clinical etoposide disposition is unknown. We studied the pharmacokinetics of etoposide and its catechol metabolite in children with acute lymphoblastic leukemia, along with polymorphisms in CYP3A4, CYP3A5, MDR1, GSTP1, UGT1A1, and VDR. Plasma pharmacokinetics were assessed at day 29, after 1 month of prednisone (n = 102), and at week 54, without prednisone (n = 44). On day 29, etoposide clearance was higher (47.4 versus 29.2 mL/min/m2, P <.0001) than at week 54. The day 29 etoposide or catechol area under the curve (AUC) was correlated with neutropenia (P =.027 and P =.0008, respectively). The relationship between genotype and etoposide disposition differed by race and by prednisone use. The MDR1 exon 26 CC genotype predicted higher day 29 etoposide clearance (P =.002) for all patients, and the CYP3A5 AA and GSTP1 AA genotypes predicted lower clearance in blacks (P =.02 and.03, respectively). The UGT1A1 6/6, VDR intron 8 GG, and VDR Fok 1 CC genotypes predicted higher week 54 clearance in blacks (P =.039,.036, and.052, respectively). The UGT1A1 6/6 genotype predicted lower catechol AUC. Prednisone strongly induces etoposide clearance, genetic polymorphisms may predict the constitutive and induced clearance of etoposide, and the relationship between genotype and phenotype differs by race.

Base Sequence↗
PubMed2003

Homocysteine, pharmacogenetics, and neurotoxicity in children with leukemia.

PURPOSE: Despite its clinical success, methotrexate (MTX) therapy is associated with toxicities such as seizures, the pathogenesis of which remains unclear. It has been suggested that hyperhomocysteinemia is caused by MTX and is responsible for its neurotoxic effects. The purposes of this study were to explore whether hyperhomocysteinemia was related to MTX administration and toxicity and whether homocysteine or MTX toxicity differed by methylenetetrahydrofolate reductase (MTHFR) or reduced folate carrier (RFC) genetic polymorphisms. PATIENTS AND METHODS: We studied 53 children with newly diagnosed acute lymphoblastic leukemia who were consecutively treated on a single clinical protocol that included two courses of high-dose MTX (high-dose methotrexate [HDMTX]; 2.5 or 5.0 g/m2 per day) as consolidation therapy. RESULTS: The study participants' median plasma homocysteine concentrations at 23 and 44 hours after HDMTX (9.00 micromol/L and 10.12 micromol/L, respectively) were greater than the concentrations immediately before HDMTX (5.77 micromol/L, P <.0001 for both comparisons). Seven days after HDMTX treatment, their plasma concentration returned to baseline. Nine patients experienced seizures, and five patients experienced thrombosis during the first 15 months of therapy, with a tendency for there to be higher plasma homocysteine in patients with seizures across all time points (P =.063) but not in patients with thrombosis (P =.59). We observed no significant differences in plasma or cerebrospinal fluid homocysteine levels or in toxicity based on the MTHFR 677C/T or RFC 80G/A genotypes. CONCLUSION: We conclude that homocysteine was transiently elevated after HDMTX and may be related to seizure risk in children with leukemia.

Carrier Proteins↗
PubMed2003

Extended follow-up of long-term survivors of childhood acute lymphoblastic leukemia.

BACKGROUND: Children who survive acute lymphoblastic leukemia are at risk for leukemia-related or treatment-related complications, which can adversely affect survival and socioeconomic status. We determined the long-term survival and the rates of health insurance coverage, marriage, and employment among patients who had attained at least 10 years of event-free survival. METHODS: A total of 856 eligible patients were treated between 1962 and 1992 in 13 consecutive clinical trials. Survival rates, the cumulative risk of a second neoplasm, and selected indicators of socioeconomic status were analyzed for the entire group and for patients who did or did not receive cranial or craniospinal radiation therapy during initial treatment. RESULTS: Fifty-six patients had major adverse events, including 8 deaths during remission, 4 relapses, and 44 second neoplasms (41 of them radiation-related); most of the second neoplasms were benign or of a low grade of malignant potential. The risk of a second neoplasm was significantly higher in the 597 patients who received radiation therapy (irradiated group) than in the 259 patients who did not receive radiation therapy (nonirradiated group) (P=0.04; estimated cumulative risk [+/-SE] at 20 years, 20.9+/-3.9 percent vs. 0.95+/-0.9 percent). The death rate for the irradiated group slightly exceeded the expected rate in the general U.S. population (standardized mortality ratio, 1.90; 95 percent confidence interval, 1.12 to 3.00), whereas that for the nonirradiated group did not differ from the population norm (standardized mortality ratio, 1.75; 95 percent confidence interval, 0.34 to 5.00). The rates of health insurance coverage, marriage, and employment in the nonirradiated group were similar to the age- and sex-adjusted national averages. Despite having health insurance rates similar to those in the general population, men and women in the irradiated group had higher-than-average unemployment rates (15.1 percent vs. 5.4 percent and 35.4 percent vs. 5.2 percent, respectively), and women in the irradiated group were less likely to be married (35.2 percent vs. 48.8 percent). CONCLUSIONS: Children with acute lymphoblastic leukemia who did not receive radiation therapy and who have attained 10 or more years of event-free survival can expect a normal long-term survival. Irradiation is associated with the development of second neoplasms, a slight excess in mortality, and an increased unemployment rate.

Adolescent↗
PubMed2003

Pharmacokinetics and pharmacodynamics of oral etoposide in children with relapsed or refractory acute lymphoblastic leukemia.

PURPOSE: To study the pharmacokinetics and pharmacodynamics of once- versus twice-daily oral etoposide in children with relapsed or refractory acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: Fifty-eight patients were randomly assigned to etoposide at 50 mg/m(2)/d with once- versus twice-daily doses for 22 days. On day 8, vincristine, asparaginase, and dexamethasone were started. Etoposide pharmacokinetics and pharmacodynamics were studied for 47, 28, and 26 patients on day 1, 8, and 22, respectively, of remission reinduction therapy. RESULTS: Of 48 patients with pharmacokinetic data, 42 (87.5%) achieved complete remission, three (6.3%) failed to achieve remission, and three (6.3%) died during induction. Median etoposide day 8 area under concentration-time curve (AUC) and cumulative AUC tended to be greater (P =.06 and P =.07, respectively) in patients (n = 23) who achieved complete remission (24 and 522 micro mol/L x h, respectively) than in patients (n = 3) who did not (14 and 303 micro mol/L x h, respectively). Three of eight patients with plasma concentrations exceeding 1.7 micro M (1 micro g/mL) for more than 8 hours daily, compared with one of 20 patients with concentrations exceeding 1.7 micro M for <or= 8 hours daily, were unable to receive all 22 days of etoposide because of toxicity. There was no difference in the AUC at day 1 or day 8 with once- versus twice-daily doses (P =.55 and P =.86, respectively). CONCLUSION: A pharmacodynamic relationship exists between systemic etoposide exposure and response to therapy when oral etoposide is used as part of remission induction regimens for relapsed or refractory childhood ALL.

Administration, Oral↗
PubMed2003

Granulocyte colony-stimulating factor and the risk of secondary myeloid malignancy after etoposide treatment.

Event-free survival for children with acute lymphoblastic leukemia (ALL) now exceeds 80% in the most effective trials. Failures are due to relapse, toxicity, and second cancers such as therapy-related myeloid leukemia or myelodysplasia (t-ML). Topoisomerase II inhibitors and alkylators can induce t-ML; additional risk factors for t-ML remain poorly defined. The occurrence of t-ML among children who had received granulocyte colony-stimulating factor (G-CSF) following ALL remission induction therapy prompted us to examine this and other putative risk factors for t-ML in 412 children treated on 2 consecutive ALL protocols from 1991 to 1998. All children received etoposide and anthracyclines, 99 of whom received G-CSF; 284 also received cyclophosphamide, 58 of whom also received cranial irradiation. There were 20 children who developed t-ML at a median of 2.3 years (range, 1.0-6.0 years), including 16 cases of acute myeloid leukemia, 3 myelodysplasia, and 1 chronic myeloid leukemia. Stratifying by protocol, the cumulative incidence functions differed (P =.017) according to the use of G-CSF and irradiation: 6-year cumulative incidence (standard error) of t-ML of 12.3% (5.3%) among the 44 children who received irradiation without G-CSF, 11.0% (3.5%) among the 85 children who received G-CSF but no irradiation, 7.1% (7.2%) among the 14 children who received irradiation plus G-CSF, and 2.7% (1.3%) among the 269 children who received neither irradiation nor G-CSF. Even when children receiving irradiation were excluded, the incidence was still higher in those receiving G-CSF (P =.019). In the setting of intensive antileukemic therapy, short-term use of G-CSF may increase the risk of t-ML.

Adolescent↗
PubMed2003

International collaboration on childhood leukemia.

The current cure rate of childhood acute lymphoblastic leukemia has reached 80% in many industrialized countries, but in developing countries the rate is often less than 10%. To advance the cure rate, investigators have formed several parallel initiatives in both industrialized and developing countries through international collaboration and partnership. Among industrialized countries, investigators have combined data to conduct in-depth studies of the biology and heterogeneity of high-risk or drug-resistant subgroups of leukemia to identify optimal or novel treatments. Alliances have been established among government, local nongovernmental organizations, health care providers, and international groups to improve the survival rate of childhood leukemia in developing countries. "Twinning" partnerships between a well-established individual institution or study group and a pediatric cancer unit in a developing country has proved to be the most successful strategy to date.

Adolescent↗
PubMed2003

Antagonism by methotrexate on mercaptopurine disposition in lymphoblasts during up-front treatment of acute lymphoblastic leukemia.

BACKGROUND: Methotrexate is postulated to enhance mercaptopurine activation to thioguanine (INN, tioguanine) nucleotides, but the interaction has never been studied in vivo in cancer cells. METHODS: We investigated the effect of methotrexate on mercaptopurine disposition in plasma and leukemic blasts during up-front treatment of 233 children with newly diagnosed acute lymphoblastic leukemia. Children were randomized to receive intravenous mercaptopurine (1 g/m(2) over a 6-hour period) or to receive methotrexate (low dose, 6 oral doses of 30 mg/m(2), or high dose, 1 g/m(2) intravenously), followed by intravenous mercaptopurine. All combinations have been previously used in frontline trials for acute lymphoblastic leukemia. RESULTS: Compared with mercaptopurine alone, methotrexate resulted in higher plasma mercaptopurine concentrations (30.3 +/- 14.7 micromol/L versus 23.5 +/- 18.0 micromol/L, P <.001) but, conversely, a 13-fold lower thioguanine nucleotide concentration (0.57 +/- 0.66 pmol/5 x 10(6) cells versus 7.4 +/- 15.2 pmol/5 x 10(6) cells, P <.001) in bone marrow leukemic lymphoblasts. Methotrexate was also associated with higher plasma hypoxanthine concentrations compared with those of patients given mercaptopurine alone (8.7 +/- 13.5 micromol/L versus 3.8 +/- 2.5 micromol/L, P =.029). The percentage change in leukocyte counts measured over a 3-day period showed that mercaptopurine alone had little effect (mean decrease, 20% +/- 33%). In contrast, despite causing lower intracellular thiopurine active metabolite concentrations, methotrexate produced a greater decrease in leukocyte counts (mean, 53% +/- 35%) compared with those in patients receiving mercaptopurine alone (P <.0001). CONCLUSION: These pharmacologic findings in the target tissue are consistent with the recently demonstrated lack of clinical benefit of intravenous mercaptopurine in combination with methotrexate. We conclude that, in the setting of newly diagnosed acute lymphoblastic leukemia, methotrexate antagonizes thiopurine metabolite disposition in leukemic blasts after intravenous mercaptopurine.

Antimetabolites, Antineoplastic↗
PubMed2003

Recent advances in the treatment and understanding of childhood acute lymphoblastic leukaemia.

Clinical trials have advanced the cure rate of childhood acute lymphoblastic leukaemia to near 80%. Treatment response, as measured by minimal residual disease, has allowed us to refine risk classification schemes and better tailor the intensity of therapy for each patient. More complete molecular analysis of leukaemia cells, pharmacodynamic and pharmacogenetic studies, and the development of targeted therapy should ultimately lead to further improvements in treatment. Pharmacogenetic studies should allow treatment refinements that will decrease the risk of complications while maintaining high cure rates. In addition, gene expression profiling may improve the genetic classification of leukaemia and identify clinically important subgroups. It may also lead to the identification of new targets for novel antileukaemic agents.

Adolescent↗
PubMed2003

Treatment-specific changes in gene expression discriminate in vivo drug response in human leukemia cells.

To elucidate the genomics of cellular responses to cancer treatment, we analyzed the expression of over 9,600 human genes in acute lymphoblastic leukemia cells before and after in vivo treatment with methotrexate and mercaptopurine given alone or in combination. Based on changes in gene expression, we identified 124 genes that accurately discriminated among the four treatments. Discriminating genes included those involved in apoptosis, mismatch repair, cell cycle control and stress response. Only 14% of genes that changed when these medications were given as single agents also changed when they were given together. These data indicate that lymphoid leukemia cells of different molecular subtypes share common pathways of genomic response to the same treatment, that changes in gene expression are treatment-specific and that gene expression can illuminate differences in cellular response to drug combinations versus single agents.

Antineoplastic Agents↗
PubMed2003

Clinical significance of residual disease during treatment in childhood acute myeloid leukaemia.

In children with acute myeloid leukaemia (AML), morphological and karyotypic studies cannot precisely assess response to treatment, and less than one-third of patients have genetic markers for molecular studies of residual disease. We determined the usefulness of a four-colour flow cytometric strategy developed in our laboratory to study residual disease. We first compared the immunophenotypes of AML cells obtained from 54 children at diagnosis with those of cells from 59 normal or regenerating bone marrow samples. Forty-six of the 54 AML cases (85.2%) had immunophenotypes that allowed detection of 0.1-0.01% residual leukaemic cells. Of 230 bone marrow samples obtained from those 46 patients during and off treatment, 61 (26.5%) had >/= 0.1% AML cells by flow cytometry. We found that core binding factor-associated AML had a significantly better early treatment response. Mean (+/- standard error) 2-year survival estimate was 33.1 +/- 19.1% for patients with >/= 0.1% AML cells by flow cytometry after induction therapy, but 72.1 +/- 11.5% for those with < 0.1% AML cells (P = 0.022); overt recurrence of AML within the subsequent 6 months was significantly more likely in the former group. The assay described here holds promise for guiding the choice of post-remission treatment options in children with AML.

Acute Disease↗
PubMed2003

Viridans streptococcal sepsis: clinical features and complications in childhood acute myeloid leukemia.

PURPOSE: Treatment of acute myeloid leukemia (AML) is associated with substantial adverse effects, including neutropenia and infection. Viridans streptococci (VS) are a primary cause of infection and pneumonia in patients with neutropenia. The authors determined the incidence, clinical features, and complications of VS sepsis in children receiving chemotherapy for AML. METHODS: The authors retrospectively reviewed the records of 172 patients treated on their institutional protocols AML91 (n = 95) and AML97 (n = 77) and identified 36 patients who had VS sepsis. RESULTS: The 1-year cumulative incidence of VS sepsis was significantly higher in AML97 than in AML91. Patients with favorable cytogenetic features (ie, t(9;11), t(8;21), or inv(16)) had a significantly higher incidence of infection than did other patients. VS sepsis developed at various times after chemotherapy was initiated, and patients remained febrile for a median of 15 days. Twelve patients (33%) experienced hypotension, 10 (28%) acute respiratory distress syndrome, and 6 (17%) fungal infection. Twenty-three patients (64%) required intensive care, 21 (58%), oxygen therapy, and 7 (19%), vasopressor medications. One patient died of pulmonary aspergillosis after VS sepsis. The 3-year cumulative incidence of aspergillosis was higher in patients with VS sepsis than in those without. CONCLUSIONS: Although antibiotic therapy rapidly resolved VS sepsis, complications associated with this infection remained life-threatening in children receiving chemotherapy for AML.

Acute Disease↗
PubMed2003

ALK-positive anaplastic large cell lymphoma with leukemic peripheral blood involvement is a clinicopathologic entity with an unfavorable prognosis. Report of three cases and review of the literature.

Leukemic peripheral blood involvement in anaplastic large cell lymphoma (ALCL) is uncommon. We describe 3 children with such manifestations and review the features of 9 pediatric and adult patients previously described in the literature. Leukemic involvement in ALCL may occur at the time of initial diagnosis or develop during the course of disease. It most often is associated with the small cell histologic features and the t(2;5)(p23;q35). Clinical features commonly include significant respiratory distress, diffuse lung infiltrates or pleural effusions, and hepatosplenomegaly. Most cases have an aberrant T-cell immunophenotype with frequent expression of myeloid antigens, most often CD11b or CD13. Ten of the 12 cases reviewed had a poor response to therapy or early relapse. Thus, while anaplastic lymphoma kinase-positive ALCL and young patient age generally are associated with a favorable prognosis, leukemic involvement seems to identify a high-risk malignant neoplasm that requires more aggressive therapy, including hematopoietic stem cell transplantation.

Anaplastic Lymphoma Kinase↗
PubMed2003

Recombinant urate oxidase for prevention of hyperuricemia and tumor lysis syndrome in lymphoid malignancies.

Hyperuricemia is a common manifestation of lymphoid malignancies at diagnosis or after the start of chemotherapy. When accompanied by other metabolic abnormalities and/or organ failure, hyperuricemia may be a manifestation of tumor lysis syndrome (TLS). Patients at particularly high risk of such complications include those with acute lymphoblastic leukemia and advanced stage non-Hodgkin's lymphoma. Conventional measures to prevent hyperuricemia and TLS are comprised of hydration, alkalinization of body fluids, and administration of allopurinol. Although these measures are usually effective in preventing or managing hyperuricemia, approximately 20% of patients at high risk of TLS require dialysis, and many cannot receive chemotherapy as planned. Rasburicase, a recombinant form of the enzyme urate oxidase, has recently become available and may further reduce the morbidity of hyperuricemia and TLS. In this review, we provide an overview of hyperuricemia and TLS and discuss the impact of rasburicase in the overall management of these complications.

Clinical Trials as Topic↗
PubMed2002

Interim comparison of a continuous infusion versus a short daily infusion of cytarabine given in combination with cladribine for pediatric acute myeloid leukemia.

PURPOSE: To identify the optimal schedule for infusion of cytarabine (ara-C) given with cladribine (2-CdA) to pediatric patients with acute myeloid leukemia (AML), and to compare the effects of the two schedules on the pharmacokinetics of ara-C triphosphate (ara-CTP) in leukemic cells. PATIENTS AND METHODS: Forty-nine pediatric patients with newly diagnosed primary AML received a 5-day course of ara-C 500 mg/m(2)/d and 2-CdA 9 mg/m(2)/d. They were randomly assigned to receive ara-C as either a 2-hour daily infusion (arm A) or a continuous infusion (arm B). Cellular pharmacokinetics were studied on days 1 and 2. All patients then received two courses of remission induction chemotherapy with daunorubicin, ara-C, and etoposide (DAV). RESULTS: Thirty-two percent of patients (seven of 22) in arm A and 63% (17 of 27) in arm B entered complete remission (P =.045) after ara-C and 2-CdA therapy. Coadministration of 2-CdA increased the intracellular concentration of ara-CTP in 20 of 36 patients, although we found no statistically significant difference between the treatment arms in this effect (P =.63). The incidence of toxicity did not differ significantly between the two treatment arms (P =.53). After two courses of DAV, the rate of complete remission was 91% in arm A and 96% in arm B (P =.58). CONCLUSION: Intracellular accumulation of ara-CTP is increased when 2-CdA is given with ara-C, but no schedule-dependent differences in this effect were seen. The combination of 2-CdA and ara-C seems to be effective therapy for pediatric AML.

Adolescent↗
PubMed2002

Use of peripheral blood instead of bone marrow to monitor residual disease in children with acute lymphoblastic leukemia.

In children with acute lymphoblastic leukemia (ALL), response to treatment is assessed by bone marrow aspiration. We investigated whether minimal residual disease (MRD) can be effectively monitored in peripheral blood. We used flow cytometric techniques capable of detecting 1 leukemic cell among 10 000 or more normal cells to compare MRD measurements in 718 pairs of bone marrow and peripheral blood samples collected from 226 children during treatment for newly diagnosed ALL. MRD was detected in marrow and blood in 72 pairs and in marrow but not in blood in 67 pairs; it was undetectable in the remaining 579 pairs. Remarkably, findings in marrow and blood were completely concordant in the 150 paired samples from patients with T-lineage ALL: for each of the 35 positive marrow samples, the corresponding blood sample was positive. In B-lineage ALL, however, only 37 of 104 positive marrow samples had a corresponding positive blood sample. Notably, peripheral blood MRD in these patients was associated with a very high risk for disease recurrence. The 4-year cumulative incidence of relapse in patients with B-lineage ALL was 80.0% +/- 24.9% for those who had peripheral blood MRD at the end of remission induction therapy but only 13.3% +/- 9.1% for those with MRD confined to the marrow (P =.007). These results indicate that peripheral blood may be used to monitor MRD in patients with T-lineage ALL and that peripheral blood MRD may provide strong prognostic information in patients with B-lineage ALL.

Antineoplastic Combined Chemotherapy Protocols↗