Intensification of mercaptopurine/methotrexate maintenance chemotherapy may increase the risk of relapse for some children with acute lymphoblastic leukemia.

Schmiegelow K, Bjork O, Glomstein A, Gustafsson G, Keiding N, Kristinsson J, Makipernaa A, Rosthoj S, Szumlanski C, Sorensen TM, Weinshilboum R.

Departments of Pediatrics and of Biostatistics, The University Hospital and The University of Copenhagen, Denmark.

Purpose: Thioguanine nucleotides (TGNs) mediate the cytotoxicity of mercaptopurine (MP). Methylated MP metabolites (formed by thiopurine methyltransferase [TPMT]) and methotrexate (MTX) polyglutamates can inhibit de novo purine synthesis. We explored whether dose adjustment of MP and MTX by erythrocyte (E) levels of TGN and MTX (including polyglutamates) could improve outcome in childhood acute lymphoblastic leukemia (ALL). Patients and Methods: A total of 538 children with ALL were randomly assigned to have their oral MP/MTX maintenance therapy adjusted by white cell counts (WBC), E-TGN, and E-MTX (pharmacology group), or by WBC only (control group). Results: After a median follow-up of 7.8 years, 79 patients had relapsed. Cox regression analysis showed an increased risk of relapse for boys (P =.00003), high WBC at diagnosis (P =.03), pharmacology arm (6.6 times increased relapse hazard for girls), high TPMT activity (P =.002), and high average neutrophil counts during maintenance therapy (P =.0009), with a significant interaction between sex and randomization group (P =.0007). For girls, the relapse risk was 5% in the control group and 19% in the pharmacology group (P =.001) because of an increased relapse hazard during the first year after cessation of therapy. TPMT activity was the most significant predictor of relapses among girls in the pharmacology arm (P <.0001). Overall, the TPMT activity was higher for patients who relapsed after cessation of therapy compared with those who stayed in remission (girls 19.5 v 17.4 U/mL, P =.03; boys 19.3 v 18.0 U/mL, P =.04). Conclusion: Adding pharmacologically guided treatment intensification to dose adjustments by blood counts may not be warranted for girls, whereas new approaches to optimize maintenance therapy are needed for boys.

PMID: 12663723 [PubMed - in process]

Recent advances in pediatric acute lymphoblastic and myeloid leukemia.

Ravindranath Y.

Acute leukemia is the most common form of childhood cancer and is the primary cause of cancer-related mortality in children. In the United approximately 3250 cases are diagnosed annually in children and adolescents younger than 20 years, of whom 2400 have acute lymphoblastic leukemia (ALL). Treatment results in childhood ALL continue to improve, and the expected current cure rates approach 75 to 80% of all children with ALL, including T-ALL and mature B-cell ALL, the two variants that, not too long ago, had a considerably poorer prognosis compared with the common form of BpALL. The most significant new development in the past 2 years has been the development of further evidence for fetal origin of childhood leukemias, and additional evidence to support the notion that postnatal events modulating the events of immune-mediated elimination of these leukemic clones play a major role in the eventual development of clinical disease. Other epidemiologic developments include (1) increased appreciation of the role of drug-metabolizing enzymes, both in determining the predisposition to leukemia and response to therapy; and (2) both clinical observations and gene expression studies seeming to identify a new approach to the evaluation and treatment of children with MLL (11q23) rearrangements. A most remarkable new development in the induction therapy of childhood leukemia and lymphoma in the United States is the use of urate oxidase for prevention of tumor lysis syndrome and the associated uric acid nephropathy. Drug resistance, determined either on leukemic blast cells or by studies of MRD, is being looked at critically in an effort to improve the treatment results further. Consolidation with HDMTX has gained wider popularity with the realization that effective CNS prophylaxis can be achieved with intrathecal therapy plus HDMTX for consolidation. In contrast to ALL, the progress in the therapy of acute myeloid leukemia (AML) lags behind, with cure rates of approximately 40 to 50%. There is no convincing evidence for substitution of daunorubicin with other anthracyclines, nor evidence for using high-dose cytarabine during induction in childhood AML. Rather, a 3 + 10 regimen with total daunorubicin 180 mg/m and cytarabine 100 to 200 mg/ for 10 days appears to yield the best results. The most important component of the postremission chemotherapy continues to be several courses of high-dose cytarabine. The results from the MRC 10, LAME 89/91 studies and the recent BFM 93 trial with high-dose cytarabine and mitoxantrone suggest that there may be some benefit to including this combination in the postremission phase of AML. Despite these improvements in chemotherapy, allogeneic BMT from a matched family donor remains the best option for most patients (excluding Down syndrome, APL, and possibly those with inv16). Newer prognostic markers of interest include FLT3/ITD and minimal residual disease at the end of induction therapy.

PMID: 12490758 [PubMed - in process]

Treatment results of childhood acute lymphoblastic leukemia in Austria--a report of 20 years' experience.

Comment in: Wien Klin Wochenschr. 2002 Feb 28;114(4):141-2.

Attarbaschi A, Mann G, Dworzak M, Urban C, Fink FM, Dieckmann K, Riehm H, Gadner H; Austrian Cooperative Study Group.

St. Anna Children's Hospital, Vienna.

Between 1981 and 1999, 890 Austrian children with acute lymphoblastic leukemia (ALL) were treated in 5 consecutive trials using protocols from the Berlin-Frankfurt-Munster (BFM) Group. In the trials BFM-A (Austria) 81 and ALL A 84, treatment stratification was performed using a risk factor, which was calculated from the initial peripheral blast cell count, and size of liver and spleen. In the following studies (BFM-A 86, 90 and 95) early response to a 7-day systemic mono-therapy with prednisone (as measured by the peripheral blast cell count) was used as an overriding stratification factor; in order to reduce the need for cranial radiotherapy, all patients received high-dose methotrexate (5 g/m2) for preventive central nervous system treatment. Event-free survival (EFS) rates increased from study BFM-A 81 (n = 141, probability (p) of EFS: 59% +/- 4%) and study ALL A 84 (n = 127, pEFS: 67% +/- 4%) to 77% +/- 4% in trial BFM-A 86 (n = 142), 79% +/- 3% in trial BFM-A 90 (n = 256), and 84% +/- 3% in trial BFM-A 95 (n = 224). However, the prognosis for high-risk patients has not significantly improved within the last 20 years (pEFS: 50%). Furthermore, conventional risk factors such as leukocyte count and age at time of diagnosis, could not be used to indicate patients in the low and intermediate risk group who might eventually relapse. Thus, in trial BFM-A 2000, detection of minimal residual disease by polymerase chain reaction-based methods after 5 and 12 weeks of therapy was introduced for treatment stratification. Minimal residual disease was prospectively shown to predict relapses more precisely and, as a matter of fact, may allow a more exact definition of which patients are at risk and which patients belong to the subgroup with a good prognosis despite reduced treatment.

PMID: 12060981 [PubMed - indexed for MEDLINE]

Continuing therapy for childhood acute lymphoblastic leukaemia: clinical and cellular pharmacology of methotrexate, 6-mercaptopurine and 6-thioguanine.

Estlin EJ.

Department of Paediatric Oncology, Royal Manchester Children's Hospital, Pendlebury, Manchester M27 4HA, UK. eestlin@mch.srht.nwest.nhs.uk

Across the world, therapy with 6-mercaptopurine (6-MP) and methotrexate (MTX) forms the basis of the continuing therapy of childhood acute lymphoblastic leukaemia (ALL). In this review, the pharmacological determinants of the sensitivity of human leukaemia cell lines and lymphoblasts derived from children with ALL will be discussed. In addition, clinical pharmacological studies of 6-MP and MTX in relation to the continuing therapy with childhood ALL will be reviewed. For 6-MP in vitro, prolonged exposure times to relatively high extracellular drug concentrations are necessary for cytotoxicity, and these concentrations are much higher than those achieved during continuing therapy for childhood ALL. For MTX, plasma concentrations are achieved during continuing therapy that would be cytotoxic to human leukaemia cells during prolonged exposures in vitro. For both MTX and 6-MP, wide inter- and intrapatient variation in plasma pharmacokinetic parameters has been described. For 6-MP and MTX, cellular pharmacological studies have been largely restricted to erythrocytes as a surrogate of the possible effects in leukaemic blasts. Although measures of the pharmacology of 6-MP and MTX in erythrocytes has been related to prognosis in many studies, 6-MP systemic exposure and the dose intensity of 6-MP and MTX actually received by children during this phase of therapy seems to be the most important determinant of efficacy. Further studies will be needed to determine the importance of pharmacokinetic variability during continuing therapy as a determinant of outcome for children with ALL. In this respect, minimal residual disease status during this phase of treatment may prove to be a useful pharmacodynamic endpoint. Copyright 2002, Elsevier Science Ltd. All rights reserved.

Publication Types: Review Review, Tutorial

PMID: 11908928 [PubMed - indexed for MEDLINE]

Effect of methotrexate polyglutamates on thioguanine nucleotide concentrations during continuation therapy of acute lymphoblastic leukemia with mercaptopurine.

Dervieux T, Hancock M, Evans W, Pui CH, Relling MV.

Department of Pharmaceutical Sciences, St Jude Children's Research Hospital, Memphis, TN 38105, USA.

Methotrexate is widely administered with mercaptopurine, a prodrug requiring activation into thioguanine nucleotides (TGN) to exert antileukemic effects. In vitro, methotrexate enhances TGN formation, but in vivo, such enhancement has yet to be demonstrated. We investigated whether TGN concentrations were related to methotrexate concentrations in children with acute lymphoblastic leukemia who received a weekly intravenous methotrexate (40 mg/m(2)) dose combined with daily mercaptopurine (75 mg/m(2)). A total of 141 erythrocyte TGN concentrations were measured with erythrocyte methotrexate polyglutamates (MTX-PG) concentrations in 87 patients. Average TGN concentrations ranged from 137 to 958 pmol/8 x 10(8) cells (median 389), average total MTX-PG concentrations (MTX- PG(1-7)) from 0.60 to 97.7 pmol/10(9)cells (median 29), and average long chain polyglutamate concentrations (MTX-PG(5-7)) from 0 to 8.35 pmol/10(9) cells (median 2.43). Higher TGN concentrations correlated with higher MTX-PG(5-7) concentrations (P = 0.002). These data support the practice of administering methotrexate with mercaptopurine during continuation therapy of acute lymphoblastic leukemia.

PMID: 11840287 [PubMed - indexed for MEDLINE]

Pneumocystis carinii pneumonia during maintenance treatment of childhood acute lymphoblastic leukemia.

Poulsen A, Demeny AK, Bang Plum C, Gjerum Nielsen K, Schmiegelow K.

Section of Pediatric Hematology and Oncology, Pediatric Clinic II, The Juliane Marie Center, The Copenhagen University Hospital, Rigshospitalet, Denmark.

BACKGROUND: Pneumocystis carinii pneumonia (PCP) is a wellknown risk among patients with deficient T-cell function such as children treated for acute lymphoblastic leukemia (ALL). The purpose of this study was to estimate the risk for PCP during maintenance treatment (MT) to identify patients at risk who could benefit from prophylaxis. PROCEDURE: We registered all episodes of PCP during MT in 71 children diagnosed between January 1992 and June 1997 with non-B-cell ALL at The Copenhagen University Hospital. Sulphametoxazole and trimetroprim (SMX/TMP) prophylaxis against PCP was given during induction and consolidation therapy but stopped prior to MT with oral methotrexate/6-mercaptopurine. Patients with standard (SR), intermediate (IR), and high risk (HR) ALL started MT at 3, 8, and 15 months from diagnosis, respectively. RESULTS: The HR group had a cumulated risk of 70% for developing PCP, whereas the risk for PCP in children with IR and the SR was 11 and 8%, respectively (P < 0.0001). All but one of these 13 cases of PCP occurred within 8 months after cessation of SMX-TMP prophylaxis. CONCLUSIONS: The higher incidence of PCP among HR compared to non-HR patients following cessation of SMX/TMP prophylaxis probably reflects the significantly longer T-cell suppressive consolidation therapy in this group. The very low incidence of PCP during the later part of MT emphasizes that methotrexate/6-mercaptopurine MT have more impact on B-cell than on T-cell function. TMP/SMX prophylaxis should be recommended for all children treated for ALL. Copyright 2001 Wiley-Liss, Inc.

PMID: 11466718 [PubMed - indexed for MEDLINE]

6-mercaptopurine dosage and pharmacokinetics influence the degree of bone marrow toxicity following high-dose methotrexate in children with acute lymphoblastic leukemia.

Schmiegelow K, Bretton-Meyer U.

The Laboratory for Pediatric Oncology, The Pediatric Clinic II, The Juliane Marie Centre, The National University Hospital, Rigshospitalet, Copenhagen, Denmark.

Through inhibition of purine de novo synthesis and enhancement of 6-mercaptopurine (6MP) bioavailability high-dose methotrexate (HDM) may increase the incorporation into DNA of 6-thioguanine nucleotides (6TGN), the cytoxic metabolites of 6MP. Thus, coadministration of 6MP could increase myelotoxicity following HDM. Twenty-one children with standard risk (SR) and 25 with intermediate risk (IR) acute lymphoblastic leukemia (ALL) were studied. During consolidation therapy they received either three courses of HDM at 2 week intervals without concurrent oral 6MP (SR-ALL) or four courses of HDM given at 2 week intervals with 25 mg/m2 of oral 6MP daily (IR-ALL). During the first year of maintenance with oral 6MP (75 mg/m2/day) and oral MTX (20 mg/m2/week) they all received five courses of HDM at 8 week intervals. In all cases, HDM consisted of 5,000 mg of MTX/m2 given over 24 h with intraspinal MTX and leucovorin rescue. Erythrocyte levels of 6TGN (E-6TGN) and methotrexate (E-MTX) were, on average, measured every second week during maintenance therapy. When SR consolidation (6MP: 0 mg), IR consolidation (6MP: 25 mg/m2), and SR/IR maintenance therapy (6MP: 75 mg/m2) were compared, white cell and absolute neutrophil count (ANC) nadir, lymphocyte count nadir, thrombocyte count nadir, and hemoglobin nadir after HDM decreased significantly with increasing doses of oral 6MP. Three percent of the HDM courses given without oral 6MP (SR consolidation) were followed by an ANC nadir <0.5 x 10(9)/l compared to 50% of the HDM courses given during SR/IR maintenance therapy. Similarly, only 13% of the HDM courses given as SR-ALL consolidation induced a thrombocyte count nadir <100 x 10(9)/l compared to 58% of the HDM courses given during maintenance therapy. The best-fit model to predict the ANC nadir following HDM during maintenance therapy included the dose of 6MP prior to HDM (beta = -0.017, P= 0.001), the average ANC level during maintenance therapy (beta = 0.82, P = 0.004), and E-6TGN (beta = -0.0029, P= 0.02). The best-fit model to predict the thrombocyte nadir following HDM during maintenance therapy included only mPLATE (beta = 0.0057, P = 0.046). In conclusion, the study indicates that reductions of the dose of concurrently given oral 6MP could be one way of reducing the risk of significant myelotoxicity following HDM during maintenance therapy of childhood ALL.

Publication Types: Clinical Trial

PMID: 11243403 [PubMed - indexed for MEDLINE]

Long-term follow-up of the United Kingdom Medical Research Council protocols for childhood acute lymphoblastic leukaemia, 1980-1997. Medical Research Council Childhood Leukaemia Working Party.

Eden OB, Harrison G, Richards S, Lilleyman JS, Bailey CC, Chessells JM, Hann IM, Hill FG, Gibson BE.

Academic Unit of Paediatric Oncology, Christie and Royal Manchester Children's Hospital NHS Trusts, Oxford, UK.

Results of three consecutive completed UK trials (1980-1997) for childhood lymphoblastic leukaemia are presented. National accrual has progressively increased so that over 90% of all the country's ALL cases were treated on the latest trial reported, UKALLXI. From 1980 to 1990, event-free and overall survival progressively improved, following adoption of an American therapy template and use of two post-remission intensification modules. Since 1990 despite demonstration of the benefit of a third intensification module overall event-free survival (EFS) has not improved further. Survival remains high due to a good retrieval rate especially for those relapsing off treatment after receipt of two intensification pulses. Possible reasons for the plateau in event-free survival (including type and dose of induction steroid, dropping of induction anthracycline, type and dose of asparaginase, gaps early in therapy following intensification, and overall lack of compliance in maintenance) are being explored in the latest protocol ALL '97. Cranial irradiation had been successfully replaced by a long course of intrathecal methotrexate injections for the majority of patients. Age (<1 year >10 years) sex (male) and white count >50 x 10(9)/l plus slow initial bone marrow clearance were consistently the most important independent prognostic indicators during this time period. Rome/NCI criteria accurately predict standard and high-risk groups for B cell lineage, but not consistently for T cell disease. This international collaborative venture might help us to define those truly at highest risk, and how we can optimise therapy for specific subgroups including T-ALL and those with unfavourable cytogenetics.

Publication Types: Clinical Trial Meta-Analysis Randomized Controlled Trial

PMID: 11187922 [PubMed - indexed for MEDLINE]

Children's Cancer Group trials in childhood acute lymphoblastic leukemia: 1983-1995.

Gaynon PS, Trigg ME, Heerema NA, Sensel MG, Sather HN, Hammond GD, Bleyer WA.

Department of Pediatric Hematology-Oncology, Children's Hospital, Los Angeles, CA, USA.

Since 1968, the Children's Cancer Group (CCG) has treated more than 16,000 children with acute lymphoblastic leukemia (ALL). Herein, we report improvements obtained in CCG trials during two successive series of studies (1983-1988 and 1989-1995). Overall, 10-year EFS was 62% +/- 10% for the 1983-1988 series and 72% +/- 1% for the 1988-1995 series (P< 0.0001). Five-year cumulative rates of isolated CNS relapses were 5.9% and 4.4%. Therapy based on the Berlin-Frankfurt-Munster 76/79 study improved outcomes for intermediate and higher risk patients in the first series. For intermediate risk patients, delayed intensification (DI) was most crucial for improved outcome and cranial irradiation was safely replaced with maintenance intrathecal methotrexate, providing patients received intensified systemic therapy. In the second series, randomized trials showed better outcome with one vs no DI phase for lower risk patients, with two vs one DI phase for intermediate risk patients, and with the CCG 'augmented regimen' for higher risk patients with a slow day 7 marrow response. Cranial irradiation was safely replaced with additional intrathecal methotrexate for higher risk patients with a rapid day 7 marrow response. In a subsequent study, substitution of dexamethasone in place of prednisone in induction and maintenance improved outcome for standard risk patients. All patients received dexamethasone in DI. These successful treatment strategies form the basis for our current ALL trials.

Publication Types: Clinical Trial Meta-Analysis Randomized Controlled Trial

PMID: 11187913 [PubMed - indexed for MEDLINE]

High-dose methotrexate in childhood all.

Moe PJ, Holen A.

Children Hospital, Regionsykehuset i Trondheim, Trondheim, Norway.

An event-free survival is currently achieved in 70-80% of children diagnosed with acute lymphocytic leukemia (ALL). A decline in the long-term sequalae from therapy is a challenge at present. Due to the high incidence of central nervous system (CNS) relapse in ALL patients, cranial irradiation was introduced as a prophylactic measure in the beginning of the 1970s. Cranial irradiation, however, may cause secondary malignancies in the CNS. In recent years neurotoxicities have been demonstrated to follow cranial irradiation in a large proportion of ALL patients. Because of these deleterious effects, most ALL protocols are limited to the combination intrathecal and intravenous methotrexate as the standard for CNS prophylaxis. In the 1970s, an intermediate dose was administered, while from the 1980s a high dose of methotrexate was combined with intrathecal methotrexate. The regular methotrexate dose of later years has been in the range of 5-8 g/m2. The intravenous methotrexate dose has actually varied from 2 to 33.6 g/m2. The highest dose, 33.6 g/m2, has been without intrathecal instillation. In a study from Norway, high-dose methotrexate (6-8 g/m2) was used, and only two (2.2%) of 89 ALL cases showed CNS relapse, both of reversible kind. In the United Kingdom, a randomized controlled study was started in 1990. Results published so far are based on a segment of cases characterized by standard risk and white blood cell count below 50 x 10(9); a 4% reduction in CNS relapse was found for high-dose methotrexate in comparison to those treated only with long-term intrathecal methotrexate. The use of methotrexate unalterably warrants some precautions. Rescue therapy with folinic acid is usually started 36 h after initiating the methotrexate infusion. Steps are also taken to secure adequate intake of fluids and alkalinization of the urine. Provided irradiation is avoided, neurotoxicities rarely occur. For regular high-dose methotrexate adverse effects mostly involve mucositis and myelosuppresion.

Publication Types: Review Review, Tutorial

PMID: 11127393 [PubMed - indexed for MEDLINE]

Myelotoxicity, pharmacokinetics, and relapse rate with methotrexate/6-mercaptopurine maintenance therapy of childhood acute lymphoblastic leukemia.

Comment in: Pediatr Hematol Oncol. 1996 Sep-Oct;13(5):vii-x.

Schmiegelow K, Ifversen M.

Section of Pediatric Hematology and Oncology, Juliane Marie Centre, National University Hospital, Copenhagen, Denmark.

White blood cell and absolute neutrophil counts (WBC, ANC), aminotransferase (AT) levels, methotrexate (MTX) and 6-mercaptopurine (6MP) doses, metabolites in erythrocytes (E-MTX and E-6TGN), and the prognostic significance of these parameters were studied in 58 children receiving MTX/6MP maintenance therapy for acute lymphoblastic leukemia diagnosed from July 1986 to December 1991. At the end of follow-up July 1995, 13 patients had relapsed (pEFS = 0.77). Weighted means of AT, WBC, and ANC during and after maintenance therapy (mAT, mWBCON, mWBCOFF, mANCON, mANCOFF), E-MTX (mE-MTX), and E-6TGN (mE-6TGN) were calculated, as well as the product of mE-MTX and mE-6TGN (mE-MTX*6TGN), as MTX and 6MP probably act synergistically. Beyond higher MTX and 6MP doses to patients with high mWBCON, neither mWBCON, (median 3.5 x 10(9)/L), mANCON, nor mAT was correlated with the dose of MTX and 6MP, mE-MTX, mE-6TGN, or risk of relapse. Patients with mE-MTX*6TGN above or below 828 (nmol/mmol Hb)2 (median value) had pEFS values of 0.84 and 0.70, respectively (P = .16). All 5 patients who relapsed during therapy had mE-MTX*6TGN < 828 (nmol/mmol Hb)2 (P = .03). mWBCOFF and the degree of myelosuppression (= mWBCSHIFT = mWBCOFF - mWBCON; median: 2.5 x 10(9)/L) were related to age (rs = -0.50, P = .001 and rs = -0.40, P = .006, respectively). All eight relapses off therapy occurred in patients with mWBCSHIFT < 2.5 x 10(9)/L (P = .02). WBC levels during MTX/6MP therapy may underestimate the degree of MTX/6MP treatment intensity, especially in order children. Pharmacokinetic monitoring could be useful for optimizing MTX/6MP maintenance therapy.

PMID: 10897815 [PubMed - indexed for MEDLINE]

Six months of maintenance chemotherapy after intensified treatment for acute lymphoblastic leukemia of childhood.

Toyoda Y, Manabe A, Tsuchida M, Hanada R, Ikuta K, Okimoto Y, Ohara A, Ohkawa Y, Mori T, Ishimoto K, Sato T, Kaneko T, Maeda M, Koike K, Shitara T, Hoshi Y, Hosoya R, Tsunematsu Y, Bessho F, Nakazawa S, Saito T.

Department of Oncology, Kanagawa Children's Medical Center, and Department of Pediatrics, Yokohama City University School of Medicine, Yokohama, Japan.

PURPOSE: We postulated that intensification of chemotherapy immediately after remission induction might reduce the leukemic cell burden sufficiently to allow an abbreviated period of antimetabolite therapy. PATIENTS AND METHODS: Three hundred forty-seven children (ages 1 to 15 years) with previously untreated acute lymphoblastic leukemia (ALL) were enrolled onto the Tokyo L92-13 study, which excluded patients with mature B-cell ALL and patients less than 1 year old. One hundred twenty-four patients were classified as standard risk, 122 as high risk, and 101 as extremely high risk, according to age, peripheral-blood leukocyte count, selected genetic abnormalities, and immunophenotype. All subjects received four drugs for remission induction, followed by a risk-directed multidrug intensification phase and therapy for presymptomatic leukemia in the CNS. Maintenance chemotherapy with oral mercaptopurine and methotrexate was administered for 6 months, with all treatment stopped by 1 year after diagnosis. RESULTS: The mean (+/- SD) event-free survival (EFS) and overall survival rates for all patients were 59.5% +/- 3.4% and 81.5% +/- 2.2%, respectively, at 5. 5 years after diagnosis. EFS rates by risk category were similar (60. 2% +/- 6.0% for standard risk, 57.7% +/- 5.6% for high risk, and 62. 5% +/- 5.7% for extremely high risk), whereas overall survival rates differed significantly (91.2% +/- 2.7%, 80.0% +/- 4.1%, and 72.1% +/- 4.5%, respectively, P <.0001 by the log-rank test). There were 107 relapses. Eighty-five (79.4%) of these 107 patients achieved second complete remissions, with subsequent EFS rates of 61.5% +/- 7. 9% (standard risk), 42.6% +/- 8.1% (high risk), and 9.6% +/- 6.4% (extremely high risk). Of the five risk factors analyzed, only the response to prednisolone monotherapy among extremely high-risk patients proved important. CONCLUSION: Early treatment intensification did not compensate for a truncated phase of maintenance chemotherapy in children with standard- or high-risk ALL. However, 6 months of antimetabolite treatment seemed adequate for extremely high-risk patients who were good responders to prednisolone and received intensified chemotherapy that included high-dose cytarabine early in the clinical course.

Publication Types: Clinical Trial

PMID: 10735899 [PubMed - indexed for MEDLINE]

Mercaptopurine therapy intolerance and heterozygosity at the thiopurine S-methyltransferase gene locus.

Comment in: J Natl Cancer Inst. 1999 Dec 1;91(23):1983-5.

Relling MV, Hancock ML, Rivera GK, Sandlund JT, Ribeiro RC, Krynetski EY, Pui CH, Evans WE.

Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. mary.relling@stjude.org

BACKGROUND: Patients with acute lymphoblastic leukemia are often treated with 6-mercaptopurine, and those with homozygous deficiency in thiopurine S-methyltransferase (TPMT) enzyme activity have an extreme sensitivity to this drug as a result of the accumulation of higher cellular concentrations of thioguanine nucleotides. We studied the metabolism, dose requirements, and tolerance of 6-mercaptopurine among patients with different TPMT phenotypes. METHODS: We compared, by use of statistical modeling, 6-mercaptopurine pharmacology and tolerance in 180 patients who achieved remission on St. Jude Children's Research Hospital Protocol Total XII composed of weekly methotrexate (40 mg/m(2)) and daily oral 6-mercaptopurine (75 mg/m(2)) given for 2.5 years, interrupted every 6 weeks during the first year for treatment with either high-dose methotrexate or teniposide plus cytarabine. Statistical tests were two-sided. RESULTS: Erythrocyte concentrations of thioguanine nucleotides (pmol/8 x 10(8) erythrocytes) were inversely related to TPMT enzyme activity (P<.01), with averages (+/- standard deviations) of 417 (+/-179), 963 (+/-752), and 3565 (+/-1282) in TPMT homozygous wild-type (n = 161), heterozygous (n = 17), and homozygous-deficient (n = 2) patients, respectively. There was complete concordance between TPMT genotype and phenotype in a subset of 28 patients for whom TPMT genotype was determined. There were no sex differences in thioguanine nucleotide concentrations (P =.24), TPMT enzyme activity (P =.22), or average weekly prescribed dose of 6-mercaptopurine (P=.49). The cumulative incidence of 6-mercaptopurine dose reductions due to toxicity was highest among patients homozygous for mutant TPMT (100%), intermediate among heterozygous patients (35%), and lowest among wild-type patients (7%) (P<.001), with average (+/- standard deviation) final weekly 6-mercaptopurine doses of 72 (+/-60), 449 (+/-160), and 528 (+/-90) mg/m(2), respectively. Lowering doses of 6-mercaptopurine in TPMT heterozygotes and in deficient patients allowed administration of full protocol doses of other chemotherapy while maintaining high thioguanine nucleotide concentrations. CONCLUSION: We conclude that genetic polymorphism in TPMT is an important determinant of mercaptopurine toxicity, even among patients who are heterozygous for this trait.

Publication Types: Clinical Trial Randomized Controlled Trial

PMID: 10580024 [PubMed - indexed for MEDLINE]

The interaction of 6-mercaptopurine (6-MP) and methotrexate (MTX).

Giverhaug T, Loennechen T, Aarbakke J.

Department of Pharmacology, Institute of Pharmacy, University of Tromso, Norway. trudeg@farmasi.uit.no

The antimetabolites 6-mercaptopurine (6-MP) and methotrexate (MTX) are the cornerstones in the maintenance treatment of children's acute lymphoblastic leukemia (ALL). The biochemical mechanisms underlying the increased therapeutic efficacy of the combination of these drugs have not yet been elucidated. However, both drugs interact with important pathways. such as purine de novo synthesis (PDNS), purine salvage, and methylation reactions. A review of the mechanistic aspects of the interactions between 6-MP and MTX is given.

Publication Types: Review Review, Tutorial

PMID: 10523073 [PubMed - indexed for MEDLINE]

Prognostic importance of 6-mercaptopurine dose intensity in acute lymphoblastic leukemia.

Relling MV, Hancock ML, Boyett JM, Pui CH, Evans WE.

Departments of Pharmaceutical Sciences, Hematology/Oncology, and Biostatistics and Epidemiology, St Jude Children's Research Hospital, Memphis, TN, USA.

6-Mercaptopurine (6MP) and methotrexate are the backbone of continuation therapy for childhood acute lymphoblastic leukemia (ALL). In studies of oral 6MP and methotrexate, indices of chronic systemic exposure to active metabolites of these agents, namely, red blood cell (RBC) concentrations of methotrexate polyglutamates (MTXPGs) and thioguanine nucleotides (TGNs) have positively correlated with event-free survival (EFS). Our objective was to evaluate whether MTXPGs, TGNs, and the dose intensity of administered methotrexate and 6MP were prognostic in the setting of a treatment protocol in which all treatment was coordinated through a single center, and the weekly doses of methotrexate were given parenterally. On protocol Total XII, 182 children achieved remission and received weekly methotrexate 40 mg/m2 parenterally and daily oral 6MP, interrupted every 6 weeks during the first year by pulse chemotherapy. A total of 709 TGN, 418 MTX-PG, and 267 thiopurine methyltransferase (TPMT) measurements, along with complete dose intensity information (dose received divided by protocol dose per week) for 19,046 weeks of 6MP and methotrexate, were analyzed. In univariate analyses, only higher dose intensity of 6MP and of weekly methotrexate were significant predictors of overall EFS (P =.006 and .039, respectively). The occurrence of neutropenia was associated with worse outcome (P =.040). In a multivariate analysis, only higher dose intensity of 6MP (P =.020) was a significant predictor of EFS, with lower TPMT activity (P =.096) tending to associate with better outcome. 6MP dose intensity was also associated (P =.007) with EFS among patients with homozygous wild-type TPMT phenotype. Lower 6MP dose intensity was primarily due to missed weeks of therapy and not to reductions in daily dose. We conclude that increased dose-intensity of oral 6MP is an important determinant of EFS in ALL, particularly among those children with a homozygous wild-type TPMT phenotype. However, increasing intensity of therapy such that neutropenia precludes chemotherapy administration may be counterproductive.

Publication Types: Clinical Trial

PMID: 10216075 [PubMed - indexed for MEDLINE]

Pharmacokinetics and pharmacodynamics of oral methotrexate and mercaptopurine in children with lower risk acute lymphoblastic leukemia: a joint children's cancer group and pediatric oncology branch study.

Balis FM, Holcenberg JS, Poplack DG, Ge J, Sather HN, Murphy RF, Ames MM, Waskerwitz MJ, Tubergen DG, Zimm S, Gilchrist GS, Bleyer WA.

Pediatric Oncology Branch, National Cancer Institute, Bethesda, MD; and the Children's Cancer Group, Arcadia, CA, USA. balisf@nih.gov

We prospectively assessed the pharmacokinetics of methotrexate, mercaptopurine, and erythrocyte thioguanine nucleotide levels in a homogenous population of children with lower risk acute lymphoblastic leukemia and correlated pharmacokinetic parameters with disease outcome. The maintenance therapy regimen included daily oral mercaptopurine (75 mg/m2) and weekly oral methotrexate (20 mg/m2). One hundred ninety-one methotrexate doses and 190 mercaptopurine doses were monitored in 89 patients. Plasma drug concentrations of both agents were highly variable. The area under the plasma concentration-time curve (AUC) of methotrexate ranged from 0.63 to 12 micromol*h/L, and the AUC of mercaptopurine ranged from 0.11 to 8 micromol*h/L. Drug dose, patient age, and duration of therapy did not account for the variability. Methotrexate AUC was significantly higher in girls than boys (P =.007). There was considerable intrapatient variability for both agents. Erythrocyte thioguanine nucleotide levels were also highly variable (range, 0 to 10 pmol/g Hgb) and did not correlate with mercaptopurine dose or AUC. A Cox regression analysis showed that mercaptopurine AUC was a marginally significant (P =.043) predictor of outcome, but a direct comparison of mercaptopurine AUC in the remission and relapsed patient groups failed to show a significant difference. Methotrexate and mercaptopurine plasma concentrations and erythrocyte thioguanine nucleotide levels were highly variable, but measurement of these pharmacokinetic parameters at the start of maintenance will not distinguish patients who are more likely to relapse.

Publication Types: Multicenter Study

PMID: 9808549 [PubMed - indexed for MEDLINE]

Bone marrow transplantation versus chemotherapy for maintenance of second remission of childhood acute lymphoblastic leukemia: a study of the Children's Cancer Group (CCG-1884).

Feig SA, Harris RE, Sather HN.

UCLA Children's Hospital, Los Angeles, CA, USA.

BACKGROUND: Maintenance of second remission of childhood acute lymphoblastic leukemia (ALL) with intensive chemotherapy is often unsuccessful. The major cause of treatment failure is relapse. MATERIALS AND METHODS: Of 96 children with ALL who relapsed in the marrow while on or within 1 year of completing initial therapy, 62 achieved a second remission. Nineteen patients underwent bone marrow transplantation in second remission, 11 from a human leukocyte antigen (HLA)-matched related donor, seven using autologous marrow, and one from a matched unrelated donor. The event-free survival (EFS) of transplanted patients was compared to that of patients treated with intensive chemotherapy using high-dose cytarabine, vincristine, escalating dose methotrexate, L-asparaginase, and an anthracycline (daunorubicin or idarubicin). Only those patients treated with chemotherapy who survived in second remission up to the mean time that patients were transplanted (135 days) were included in the control group (33 of 43 patients who achieved second remission). RESULTS: The actuarial 2-year event-free survival of transplanted patients is 37+/-22% (95% C.I.) compared to 18+/-13% for chemotherapy-treated patients (P=0.017). EFS for allo-transplant recipients was similar to that for auto-transplant recipients. Duration of initial remission was a strong predictor of the outcome of retrieval therapy. Patients whose initial remission was greater than 3 years had better EFS after achieving second remission (five of 11 still in remission, compared to four of 41 patients whose initial remission was less than 3 years). Adjustment in the multivariate analysis for duration of initial remission did not diminish the benefit of transplant over chemotherapy. CONCLUSIONS: While there remains considerable possibility for further improvement in EFS after achieving second remission of childhood ALL, bone marrow transplant is superior to chemotherapy in maintaining second remission.

PMID: 9324340 [PubMed - indexed for MEDLINE]

On the prognostic value of systemic methotrexate clearance in childhood acute lymphocytic leukemia.

Comment in: Leuk Res. 1997 May;21(5):435-7.

Seidel H, Nygaard R, Moe PJ, Jacobsen G, Lindqvist B, Slordal L.

Department of Paediatrics, Norwegian University of Science and Technology, Trondheim, Norway.

The prognostic value of systemic methotrexate clearance (ClMTX) during high-dose therapy was evaluated in a cohort of 42 children with acute lymphocytic leukemia (ALL). As part of an extensive chemotherapy protocol, they had received a total of 293 methotrexate (MTX) infusions in the 6-8 g/m2 dose range. At the termination of the study, when they had all been followed up for 3.5 years or more, 26 of these patients were still in continuous complete remission, whereas 16 had suffered relapse. The intrapatient variability in ClMTX during the eight courses was up to six-fold. In 67% of the patients, the maximum level of ClMTX reached at least twice the minimum value. The coefficients of variation for the intra- and interindividual variability in ClMTX were 9-57% and 26-41%, respectively. The cumulative probability of relapse, estimated by the Kaplan-Meier procedure, was increased for patients with a high ClMTX during the initial treatment course, but the difference was not significant on a 5% level. There was no significant relationship between high individual median ClMTX and subsequent relapse of ALL. However, ClMTX during the initial infusion, the time-dependent mean for ClMTX, and the individual patient's median ClMTX, were significant predictors for event-free survival in a Cox proportional hazards regression analysis. The present study demonstrates gross pharmacokinetic variability and unpredictable values of ClMTX in subsequent courses after standardized administration of MTX to paediatric patients with ALL. In spite of the association between ClMTX and prognosis shown by some of the analyses, estimates of ClMTX rates may not necessarily be related to disease outcome in a way that can be exploited to the benefit of the individual patient.

PMID: 9225071 [PubMed - indexed for MEDLINE]

Impact of morning versus evening schedule for oral methotrexate and 6-mercaptopurine on relapse risk for children with acute lymphoblastic leukemia. Nordic Society for Pediatric Hematology and Oncology (NOPHO).

Schmiegelow K, Glomstein A, Kristinsson J, Salmi T, Schroder H, Bjork O.

Section of Clinical Hematology and Oncology, Juliane Marie Center, University Hospital, Copenhagen, Denmark.

PURPOSE: To study the risk of non-B-cell acute lymphoblastic leukemia (ALL) relapse in relation to the routines of administration of oral methotrexate (MTX) and 6-mercaptopurine (6MP) and to the erythrocyte (E) levels of the intracellular cytotoxic metabolites, that is, MTX polyglutamates and 6-thioguanine nucleotides (E-MTX and E-6TGN). PATIENTS AND METHODS: E-MTX and E-6TGN levels were measured at least three times (medians, eight and nine) in 294 children with non-B-cell ALL during oral MTX and 6MP therapy. For each patient, we registered (a) the individual circadian schedule of drug administration and (b) the coadministration of food, and (c) calculated a mean (m) of all E-MTX and E-6TGN measurements and (d) the product of mE-MTX and mE-6TGN (mE-MTX*6TGN), due to their synergistic action. RESULTS: A total of 42 patients were on a morning schedule, 219 were on an evening schedule, and 33 had miscellaneous routines. A total of 149 patients took the drugs with meals, 106 took the drugs between meals, and 39 had varying routines. With a median follow-up of 78 months, ALL has recurred in 66 patients. The patients on an evening schedule had a superior outcome [probability of event-free survival (pEFS) = 0.82 +/- 0.03 vs. 0.57 +/- 0.08; p = 0.0002], whereas the coadministration of food did not significantly influence outcome. Patients with a mE-MTX*6TGN < 813 [product of median mE-MTX (4.7 nmol/mmol Hb) and mE-6TGN (173 nmol/mmol Hb)] had an inferior outcome (pEFS = 0.70 +/- 0.04 vs. 0.85 +/- 0.03; p = 0.003), even if only patients on an evening schedule were analyzed. Thus, 109 patients on the MTX/6MP evening schedule with an mE-MTX*6TGN < or = 813 (nmol/mmol Hb)2 had a pEFS of 0.89 +/- 0.03 and a probability of continuous hematopoietic remission of 0.91 +/- 0.03. CONCLUSIONS: An evening schedule should be recommended for oral MTX/6MP maintenance therapy. The value of individual dose adjustments by E-MTX and E-6TGN remains to be determined in prospective randomized trials.

PMID: 9149738 [PubMed - indexed for MEDLINE]

Peripheral blast counts at diagnosis of late isolated bone marrow relapse of childhood acute lymphoblastic leukemia predict response to salvage chemotherapy and outcome. Berlin-Frankfurt-Munster Relapse Study Group.

Buhrer C, Hartmann R, Fengler R, Rath B, Schrappe M, Janka-Schaub G, Henze G.

Department of Pediatric Hematology/Oncology, Children's Hospital, Virchow Medical Center, Humboldt University, Berlin, Germany.

PURPOSE: In newly diagnosed childhood acute lymphoblastic leukemia (ALL), a high tumor burden indicates a poor prognosis, while no such link has been established yet after relapse. The impact of the absolute peripheral blast count (PBC) at the time of relapse on the response to salvage chemotherapy after a late isolated bone marrow (BM) relapse is the subject of this prospective analysis. PATIENTS AND METHODS: Since 1983, 260 children with a first isolated BM relapse of ALL that occurred 6 months or later after elective cessation of front-line therapy were enrolled onto four consecutive multicenter trials of the Berlin-Frankfurt-Munster (BFM) Relapse Study Group. All patients received intensive multiagent induction and consolidation chemotherapy for 6 months, followed by maintenance therapy with methotrexate (MTX) and thioguanine for 2 years. Treatment of subclinical meningeal leukemia consisted of high-dose intravenous MTX and intrathecally administered cytostatic drugs, which was augmented by cranial irradiation since 1988. RESULTS: At the time relapse was diagnosed, PBC varied considerably among patients (median, 1,060/microL; range, 0 to 106,800/microL). Achievement of a second complete remission (CR) was not significantly different in children without detectable circulating blasts at relapse (37 of 38) and those with moderate (1 to 9,999/microL) PBC (165 of 171). In contrast, only 42 of 51 children with high PBC (> or = 10,000/microL) achieved a second CR (P = .0015). At a median follow-up time of 40 months, the 10-year event-free survival (EFS) probability was significantly (P = .0001) higher in children without circulating blasts (.64) than in children with moderate PBC (.32) or high PBC (.10). There was a preponderance of boys in the group without detectable circulating blasts, while the three PBC-defined groups did not differ with respect to frontline treatment, age at initial diagnosis, age at relapse, time off therapy, or salvage treatment protocol. On sequential univariate and multivariate analysis, only duration of first remission > or = 48 months was an additional independent indicator of adverse prognosis, while preventive cranial irradiation improved outcome independently of PBC. CONCLUSION: The absence of blasts on peripheral-blood smears at the time of a first late isolated BM relapse of childhood ALL is associated with a favorable response and prognosis in chemotherapy-treated children, who should be regarded as ineligible for bone marrow transplantation (BMT) unless a second round of chemotherapy has failed to produce a response.

PMID: 8874343 [PubMed - indexed for MEDLINE]

Unrelated donor bone marrow transplantation for children with relapsed acute lymphoblastic leukaemia in second complete remission.

Oakhill A, Pamphilon DH, Potter MN, Steward CG, Goodman S, Green A, Goulden P, Goulden NJ, Hale G, Waldmann H, Cornish JM.

Royal Hospital for Sick Children, Bristol.

Allogeneic sibling bone marrow transplantation (BMT) is the recommended treatment for relapsed childhood acute lymphoblastic leukaemia (ALL), but appropriate donors are only available in 30% of cases. Unfortunately, BMT from unrelated donors (UD) has been associated with high rates of severe graft-versus-host disease (GvHD) and transplant-related mortality (TRM). In an attempt to improve outcome in UD-BMT we have assessed the impact of T-cell depletion using CAMPATH-1 (anti-CD52) monoclonal antibodies in 50 consecutively referred patients with relapsed ALL in second remission. All were previously treated according to MRC protocols UKALL X and XI, and then given chemotherapy on MRC R1 from relapse until UD-BMT, 19 patients had relapsed on and 31 off therapy. Patients and donors were fully matched at HLA-A, -B, -DR and -DQ loci in 29 cases and mismatched in 21 (four mismatched for more than one antigen). Pre-transplant conditioning comprised CAMPATH-1G, cyclophosphamide and total body irradiation. Bone marrow was T-cell depleted in vitro using CAMPATH-1 antibodies. Additional GvHD prophylaxis consisted of cyclosporin A (42 cases), cyclosporin plus methotrexate (four) or none (four). 47 patients engrafted. The incidence of acute GvHD was very low: two patients with grade II disease in the matched group, four with grade II-IV in the mismatched group. Only four patients have chronic GvHD. The actuarial event-free survival (EFS) at 2 years is 53%, with no significant difference between the matched and mismatched group. Further leukaemic relapse was the most important cause of failure. These results are similar to the most favourable published reports for HLA-matched sibling BMT in relapsed ALL.

PMID: 8790160 [PubMed - indexed for MEDLINE]

Clinical and experimental pharmacokinetic interaction between 6-mercaptopurine and methotrexate.

Innocenti F, Danesi R, Di Paolo A, Loru B, Favre C, Nardi M, Bocci G, Nardini D, Macchia P, Del Tacca M.

Institute of Medical Pharmacology, University of Pisa, Italy.

Clinical and experimental pharmacokinetic interaction between 6-mercaptopurine (6-MP) and methotrexate (MTX) was investigated in patients as well as in rats and in HL-60 human leukemic cells. Ten children affected by acute lymphoblastic leukemia (ALL) in remission received daily doses of 6-MP given at 25 mg/m2 and i.v. infusion of high-dose MTX at 2 or 5 g/m2 once every other week. When 6-MP was given alone, the mean peak plasma concentration (Cmax) and area under the curve (AUC) of 6-MP were 72.5 ng/ml and 225.3 h ng ml(-1). Concurrent treatment with MTX at 2 or 5 g/m2 resulted in a mean increase of 108% and 121% in the Cmax and of 69% and 93% in the AUC, respectively. In rats treated with an oral dose of 6-MP at 75 mg/m2, MTX given i.p. at 5 g/m2 produced mean increases of 110% and 230% in the Cmax and AUC of 6-MP, respectively. In HL-60 human leukemic cells incubated with 6-MP at 250 ng/ml, the cumulative intracellular concentration of 6-thioguanine and 6-MP nucleotides was not significantly modified by treatment with 20 micrograms/ml of MTX. The present findings indicate that high-dose MTX enhances the bioavailability of 6-MP as evidenced by the observed increases in the plasma Cmax and AUC of 6-MP in humans and animals.

PMID: 8599862 [PubMed - indexed for MEDLINE]

Plasma and urine levels of methotrexate and 7-hydroxymethotrexate in children with ALL during maintenance therapy with weekly oral methotrexate.

Skoglund KA, Soderhall S, Beck O, Peterson C, Wennberg M, Hayder S, Bjork O.

Department of Pediatric Oncology, Karolinska Hospital, Stockholm, Sweden.

A new high-performance liquid chromatographic assay was used to determine methotrexate (MTX) and its main metabolite, 7-hydroxymethotrexate (7-OH-MTX), in the plasma (n = 17) and urine (n = 14) of children (age 3-12 years) on maintenance therapy for acute lymphocytic leukemia (n = 14) or non-Hodgkin's lymphoma (n = 3). Each child received oral doses of weekly MTX (4.0-29 mg/m2) and daily 6-mercaptopurine (40-111 mg/m2). Plasma samples were collected daily from two children during the 1-week dose interval. A limited sampling strategy was designed, whereby 2 days of blood sampling were used in the other 15 patients. Morning urine samples were collected daily for 1 week following MTX intake from 14 of the children. MTX was detectable in all plasma and urine samples for the entire dose interval. The main metabolite, 7-OH-MTX, could be detected in plasma and urine from all patients on the first day after dose intake but only in a few patients during the whole dose interval. Interpatient variability of MTX and 7-OH-MTX levels was high at all points during the week. Significant correlation were found between the urinary MTX levels on days 2 and 7 and plasma MTX levels on day 2 after intake. No significant correlation was found between drug levels in plasma or urine and liver function tests in the children showing signs of mild liver injury. This assay provides a tool for further studies on the role of pharmacokinetics for the clinical effects of weekly oral low-dose MTX given alone or in combination with 6-mercaptopurine.

Publication Types: Clinical Trial

PMID: 8272008 [PubMed - indexed for MEDLINE]

Liver function studies in children with acute lymphocytic leukemia after cessation of therapy.

Bessho F, Kinumaki H, Yokota S, Hayashi Y, Kobayashi M, Kamoshita S.

Department of Pediatrics, University of Tokyo Hospital, Japan.

We investigated liver function in 27 children with acute lymphocytic leukemia (ALL) after cessation of therapy. Induction therapy consisted of prednisolone+vincristine (VP regimen) alone (16 patients) or with addition of daunorubicin (4 patients) or L-asparaginase (7 patients). Patients treated with VP regimen received short courses of VP regimen every 12 weeks for the first year of maintenance. Twenty-five patients remained in first complete remission and had completed 3-year maintenance therapy with methotrexate (MTX) and 6-mercaptopurine (6-MP) 1-7 years prior to this study. Twenty-three patients had received transfusions of packed red blood cells or fresh whole blood (1-11 units; median: 2 units) but none had evidence of either hepatitis B or hepatitis C. Alanine aminotransferase (ALT), which was measured every 3 months during maintenance therapy, had values more than three times the upper limit of the normal range in 25% of the measurements in more than half of the patients. However, by 3 months after the completion of maintenance therapy, ALT had normalized in all patients and remained normal in all but two patients until the time of this study. Serum bilirubin, serum albumin, and prothrombin time were all within normal limits. Fasting and 2-hour postprandial total serum bile acids were high in 5 of 13 patients and in 6 of 13 patients, respectively. The ratio of cholic acids+deoxycholic acids to chenodeoxycholic acids+lithocholic acids was below 1 in all but two patients, whereas this ratio was above 1 in all controls. Our bile acid profile results indicate the necessity of careful long-term follow-up of survivors of ALL treated with hepatotoxic chemotherapy during childhood.

PMID: 8202032 [PubMed - indexed for MEDLINE]

6-Mercaptopurine cumulative dose: a critical factor of maintenance therapy in average risk childhood acute lymphoblastic leukemia.

Dibenedetto SP, Guardabasso V, Ragusa R, Di Cataldo A, Miraglia V, D'Amico S, Ippolito AM.

Division of Pediatric Hematology-Oncology, University of Catania, Italy.

A multivariate survival analysis including gender, age, log white blood cell (WBC) count, liver and spleen size at diagnosis, mean log WBC count during maintenance therapy, and the prescribed cumulative doses of 6-mercaptopurine (6-MP), methotrexate (MTX), vincristine (VCR), and prednisone (PDN) during maintenance therapy was performed on 53 children with average-risk acute lymphoblastic leukemia (ALL). The 6-MP cumulative dose prescribed during maintenance therapy resulted in the most important statistically significant independent prognostic factor. Patients who received less than the median cumulative dose of 6-MP (86% of planned protocol dose) fared significantly worse than the other patients, regardless of WBC count at diagnosis, gender, age, and other factors studied. Therefore, 6-MP cumulative dose during maintenance therapy may be the critical factor for effective maintenance therapy in childhood ALL.

PMID: 8060809 [PubMed - indexed for MEDLINE]

Methotrexate and 6-mercaptopurine maintenance therapy for childhood acute lymphoblastic leukemia: dose adjustments by white cell counts or by pharmacokinetic parameters?

Schmiegelow K, Schroder H, Schmiegelow M.

Department of Pediatrics, University Hospital, Rigshospitalet, Copenhagen, Denmark.

In a consecutive study of 14 boys and 17 girls with non-B-cell ALL who were > or = 1 year of age at diagnosis, the degree of myelosuppression during the last year of MTX/6MP maintenance therapy was analyzed in relation to the erythrocyte concentration of MTX polyglutamates and 6-thioguanine nucleotides (E-MTX and E-6TGN, the respective major cytotoxic metabolites of MTX and 6MP). For each patient, E-MTX and E-6TGN levels were measured 2-15 (median, 6) and 2-17 (median, 7) times, respectively. From these measurements, arithmetic means of E-MTX and E-6TGN were calculated (mE-MTX and mE-6TGN, respectively). Since MTX and 6MP probably work synergistically, the product of mE-MTX and mE-6TGN was calculated for each patient (mE-MTX x 6TGN). The degree of myelosuppression was registered as the mean WBC determined following cessation of the therapy minus the mean WBC measured during the therapy (mWBCshift). The mean WBCs measured on therapy (mWBC(on)) and off therapy were highly correlated (r = 0.48, P = 0.009). The median mWBCshift was 2.7 x 10(9)/l (range, 1.4-4.8 x 10(9)/l). In a multivariate regression analysis, the best-fit model to predict the mWBCshift included mE-MTX x 6TGN, age at drug withdrawal, and mWBC in the order given [mWBCshift = 4.3 + 0.00089 x (mE-MTX x 6TGN) - 0.097 x age - 0.41 x mWBC(on); global rs = 0.66, P = 0.0002]. Thus, the patients with higher mE-MTX x 6TGN values, the younger patients, and the patients with the lowest WBC during therapy had the most pronounced degree of myelosuppression as measured by mWBCshift. These results indicate that E-MTX and E-6TGN may give a better reflection of the treatment intensity than do the WBCs alone.

PMID: 8004753 [PubMed - indexed for MEDLINE]

Intensification of treatment and survival in all children with lymphoblastic leukaemia: results of UK Medical Research Council trial UKALL X. Medical Research Council Working Party on Childhood Leukaemia.

Comment in: Lancet. 1995 Mar 11;345(8950):653.

Chessells JM, Bailey C, Richards SM.

Department of Haematology and Oncology, Institute of Child Health, London, UK.

The UK Medical Research Council trial MRC UKALL X was designed to investigate the benefit of one or two courses of additional intensification therapy in children with acute lymphoblastic leukaemia receiving standard treatment. From 1985 to 1990 1612 children, comprising more than 90% of eligible cases in the UK, were treated with intensive induction therapy, central nervous system directed therapy with cranial irradiation and intrathecal methotrexate, and continuing treatment for 2 years. 1171 children were randomised to receive additional intensification therapy at 5 weeks, 20 weeks, both, or neither. At follow-up of at least 3 years disease-free survival for all children at 5 years was 62% (95% confidence interval [Cl] 60.0-64.4), a significant improvement over the 56% (53.0-59.6) found in the preceding MRC UKALL trial. The 5-year disease-free survival was 71% (65.5-76.1) for children randomised to two blocks of intensification therapy, this being significantly better than the 62% (56.6-68.0), 61% (55.7-67.1), and 57% (50.9-62.7) rates for the groups randomised to one intensification block at 5 weeks, one at 20 weeks, and no intensification, respectively. The benefits of intensification therapy were seen irrespective of clinical factors known to influence outcome such as age, sex, and initial leucocyte count. We conclude that the addition of two courses of intensification therapy has produced a 14% improvement in disease-free survival and an 11% improvement in overall survival for the randomised patients. This additional treatment is of benefit to all children with acute lymphoblastic leukaemia, even those traditionally deemed at lower risk of relapse.

Publication Types: Clinical Trial Randomized Controlled Trial

PMID: 7823668 [PubMed - indexed for MEDLINE]

Allogeneic bone marrow transplantation for childhood acute lymphoblastic leukemia in second remission: factors predictive of survival, relapse and graft-versus-host disease.

Moussalem M, Esperou Bourdeau H, Devergie A, Baruchel A, Ribaud P, Socie G, Parquet N, Traineau R, Hirsch I, Schaison G, et al.

Bone Marrow Transplant Unit, Saint-Louis Hospital, Paris, France.

Between 1983 and 1993, 42 patients with acute lymphoblastic leukemia (ALL) in second complete remission (CR) underwent an allogeneic HLA-identical bone marrow transplant (BMT; there was one family mismatched graft). The conditioning regimens varied, consisting of cyclophosphamide (CY) and total body irradiation (TBI; n = 10); CY, TBI, Ara C, VP-16 (n = 11); TBI, Ara C, melphalan (n = 20) (TAM) or other (n = 1). Cyclosporine A (CsA) (n = 15) or CsA and methotrexate (MTX) (n = 24) were the main regimens for prophylaxis of graft-versus-host disease (GVHD). Nineteen of 42 patients are alive in CR ranging from 1 to 72 months after BMT with a median follow-up of 36 months. The 4-year actuarial survival rate was 53%. The actuarial relapse rate was 17%. Twenty three patients died: 4 patients of leukemic relapse, 9 of infection, 2 of acute GVHD, 2 of multiorgan failure after chronic GVHD, 2 of a secondary tumour and 4 patients died of other causes. Several pre- and post-transplant characteristics were analyzed to determine predictive factors for survival, relapse and GVHD. The relapse rate was significantly influenced by the type of conditioning regimen with no relapse in the TBI, Ara C, melphalan group. The analysis of long-term sequelae shows that there are no severe complications in this last group. Our results confirm that allogeneic BMT can lead to long-term survival for children with ALL in second CR and suggest an advantage of using the TAM conditioning regimen in the eradication of the leukemic disease.

PMID: 7581095 [PubMed - indexed for MEDLINE]

Acute lymphoblastic leukemia in children: current status, controversies, and future perspective.

Miller LP, Miller DR.

Disease-free survival (DFS) in childhood ALL is 60%, and survival in good, average, and poor prognostic groups defined by initial WBC and age is 90, 60, and 45%, respectively. Additional immunological, morphological, biochemical, cytokinetic, and cytogenetic factors have been identified, illustrating the heterogeneity of ALL and its derivation from malignant clones at various stages of differentiation and with varying rates of proliferation. Of biologic importance, these factors may refine further the characteristic features of clinically-determined prognostic groups. Multivariate analysis of large prospective trials with homogeneous therapy will be required to determine the independent prognostic importance of these factors. Current treatment strategies in ALL include (1) tailoring therapy and its intensity to prognostic groups; (2) multiple-drug combinations in induction; (3) early use of intrathecal (IT) methotrexate (MTX); (4) CNS prophylaxis with IT MTX alone in good prognosis patients and combined cranial radiation (CXRT), 1800 rads plus IT MTX, in average and poor prognosis patients. Current studies show a CNS relapse rate of 5% in all prognostic groups. Late neuropsychological defects caused by cranial XRT and IT MTX have prompted programs designed to reduce the potential late toxicity of CNS prophylaxis. More pronounced in younger children, these abnormalities include decreased IQ, visual-motor incoordination, poor performance in mathematics, and memory dysfunction. Until 1980, more intensive induction, consolidation, and maintenance therapy had failed to prolong DFS in children with a poor prognosis. In West Germany (Berlin-Frankfurt-Muenster protocol) a 70 to 75% DFS is seen in all patients regardless of initial WBC, suggesting that effective therapy will override prognostic factors. Ultra-high-dose MTX, without cranial radiation, is also showing promise in poor prognosis patients. Other issues include the optimal duration of therapy, the role of testicular biopsies, and prophylactic testicular radiation. Recent studies suggest that prognostic factors lose their significance after 2 years of continuous complete remission and that 2 years of maintenance therapy is adequate. Bilateral open-wedge testicular biopsies have identified occult testicular disease in 8 to 10% of males. A unified approach to children with leukemia/lymphoma, a group with a particularly poor prognosis, utilizing NHL-type therapy may be more effective than conventional ALL therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Publication Types: Review

PMID: 6397264 [PubMed - indexed for MEDLINE]

Methotrexate in neutrophils in children with acute lymphoblastic leukemia.

Schroder H.

Methotrexate (MTX) and 6-mercaptopurine (6-MP) are used for maintenance therapy of acute lymphoblastic leukemia (ALL) of childhood, and both are myelotoxic. Clinically the individual tolerance to the two drugs is variable. In order to study to what extent the MTX accumulation in circulating neutrophils is related to the absolute neutrophil count (ANC), neutrophils were isolated on a discontinuous two-step Percoll gradient in 16 children with ALL in maintenance therapy. The MTX concentration in the neutrophils was determined with a sensitive radioligand binding assay. In all children except one who admitted noncompliance, MTX was found in the neutrophils in concentrations (56-460 pmol/10(9) cells) positively correlated with the weekly dose of MTX (r = 0.51, p less than 0.01). The interindividual variation was large. Children with relatively low neutrophil MTX exhibited the widest intraindividual variation of neutrophil MTX upon reexamination during continued MTX administration with the same dosage schedule. Increases in the weekly dose of MTX resulted in proportional increases in the neutrophil MTX. In half the cases the ANC was less than 1.5 X 10(9)/l. The ANC was not related to the weekly MTX dose or the daily 6-MP dose. In children with ANC greater than 1.5 X 10(9)/l there was a significant inverse correlation between the ANC and the neutrophil MTX (r = -0.71, P less than 0.01), which was not found in the group of children with ANC less than 1.5 X 10(9)/l. These findings may be explained by differences in the kinetics of the granulopoiesis between children with high and children with low neutrophil counts.

PMID: 3474084 [PubMed - indexed for MEDLINE]

The effect of methotrexate on the bioavailability of oral 6-mercaptopurine.

Balis FM, Holcenberg JS, Zimm S, Tubergen D, Collins JM, Murphy RF, Gilchrist GS, Hammond D, Poplack DG.

Fourteen children (aged 3 to 14 years) with average-risk acute lymphoblastic leukemia were studied after an oral dose of 6-mercaptopurine (6-MP) (75 mg/m2) administered alone and, on the next day, concurrently with oral methotrexate (20 mg/m2). When 6-MP was administered alone, both the peak plasma concentration (15 to 150 ng X ml-1) and the AUC (36 to 340 ng X ml-1 X hr) were highly variable. Concurrent methotrexate resulted in a 31% increase in the AUC (P less than 0.01) and a 26% increase in peak plasma levels (P less than 0.05) of 6-MP. The AUC of methotrexate correlated with the degree of increase in 6-MP plasma concentrations. These findings are consistent with previous in vitro studies demonstrating that methotrexate is an inhibitor of xanthine oxidase, the enzyme that catabolizes 6-MP to the inactive metabolite thiouric acid. Although the increases in 6-MP AUC and peak plasma concentrations resulting from concurrent methotrexate administration were statistically significant, this interaction is probably not clinically significant at standard low oral doses of methotrexate in light of the wide interpatient variability in these pharmacokinetic parameters of 6-MP.

PMID: 3470165 [PubMed - indexed for MEDLINE]

The pharmacology of orally administered chemotherapy. A reappraisal.

Poplack DG, Balis FM, Zimm S.

Rational treatment of pediatric malignancies requires a detailed knowledge of the clinical pharmacology of those antineoplastic agents used therapeutically. A number of different agents are administered by the oral route. Recently, the clinical pharmacology of 6-mercaptopurine (6-MP) and methotrexate (MTX), the two agents that are the mainstay of maintenance chemotherapy in acute lymphoblastic leukemia (ALL), were investigated. Studies of oral 6-MP indicate that, contrary to previous information, the bioavailability of this drug is relatively poor after oral administration, and that plasma 6-MP concentrations achieved after uniform oral dosing are highly variable. Similarly, study of the pharmacology of orally administered MTX indicates that there is little correlation between MTX dose and the peak serum level achieved. These findings suggest that some patients may not be exposed to adequate systemic concentrations of 6-MP and/or MTX after oral administration, and raise the possibility that the development of relapse in some patients with ALL may be the result of a pharmacologic failure of oral maintenance therapy. A comprehensive prospective study of the clinical pharmacology of MTX and 6-MP in patients with ALL undergoing maintenance chemotherapy is currently in progress.

PMID: 3459570 [PubMed - indexed for MEDLINE]

Chronopharmacokinetics of oral methotrexate and 6-mercaptopurine: is there diurnal variation in the disposition of antileukemic therapy?

Balis FM, Jeffries SL, Lange B, Murphy RF, Doherty KM, Arndt CA, Luery N, Poplack DG.

Pediatric Branch, National Cancer Institute, Bethesda, Maryland 20892.

The chronopharmacokinetics of the orally administered antileukemic drugs, 6-mercaptopurine and methotrexate, were examined in 13 children with acute lymphoblastic leukemia (ALL) to establish if there is a pharmacokinetic basis for the lower relapse rate associated with administration of these agents in the evening. Children with ALL in complete remission had plasma drug concentrations monitored for 8 h following an oral dose of either methotrexate or 6-mercaptopurine administered in the morning (8 a.m.) and the evening (8 p.m.). Total drug exposure to oral methotrexate, as measured by the mean area under the plasma concentration-time curve (AUC), was 2.75 microM.h following the morning dose and 2.77 microM.h in the evening. For 6-mercaptopurine, the mean morning AUC (198 ng.h/ml) was higher than that following the evening dose (167 ng.h/ml) (p greater than 0.05); but compared to the wide interpatient variability observed with this drug, this 20% difference is not likely to be clinically significant. These results indicate that the suggested benefit of evening drug administration is not likely to be a result of diurnal variation in drug disposition.

PMID: 2782561 [PubMed - indexed for MEDLINE]

Disposition of oral methotrexate in children with acute lymphoblastic leukemia and its relation to 6-mercaptopurine pharmacokinetics.

Koren G, Solh H, Klein J, Soldin SJ, Greenberg M.

Division of Hematology-Oncology, Toronto, Ontario, Canada.

We studied the disposition pharmacokinetics of methotrexate (MTX) given orally to 16 children with acute lymphoblastic leukemia (ALL) and its relation to the pharmacokinetics of 6-mercaptopurine (6MP) in the same children. There was an eightfold variability in area-under-concentration time-curve (AUC) of MTX achieved by the same dose. Excellent correlation existed between peak concentrations and AUC0----infinity (r = 0.95, P less than 0.001). Elimination T1/2 was between 1.34 and 5 hours (mean 2.16 +/- 0.23 hr, mean +/- SE). A weak correlation existed between AUC achieved by 1 mg/m2 MTX and patients' age or body weight. Weak but significant correlation existed between AUC achieved by 1 mg/m2 of MTX vs. 6MP (r = 0.54, P less than 0.05). In 13/16 patients peak concentrations were achieved at 60 minutes. There was a significantly larger AUC of 6MP achieved by a standardized dose in longer therapy (greater than 15 mo) vs. short therapy (less than 12 mo) (462 +/- 75 and 246 +/- 58 ng.ml-1.min.mg-1.m2, P less than 0.025). No statistical differences in AUC of MTX were found between short and long therapy. The large interpatient variability in MTX pharmacokinetics supports the possibility that differences in absorption and/or clearance of the drug may affect the clinical response. Because of the excellent correlation between peak and AUC of MTX, and because 3 measurements, at 30, 60, and 90 minutes will almost invariably identify the peak, this measurement can be used to estimate AUC for purpose of correlation with clinical outcome.

PMID: 2586358 [PubMed - indexed for MEDLINE]

Purine de novo synthesis as the basis of synergism of methotrexate and 6-mercaptopurine in human malignant lymphoblasts of different lineages.

Bokkerink JP, Bakker MA, Hulscher TW, De Abreu RA, Schretlen ED.

Department of Pediatrics, St Radboud Hospital, University of Nijmegen, The Netherlands.

Methotrexate (MTX) causes an inhibition of purine de novo synthesis (PDNS), resulting in increased intracellular availability of 5-phosphoribosyl-1-pyrophosphate (PRPP) in human malignant lymphoblasts with an active PDNS. Normal bone marrow cells and peripheral blood lymphocytes lack this capacity. The increased levels of PRPP can be used for enhanced incorporation of 6-mercaptopurine (6MP), indicating a potential time-, sequence- and dose-dependent synergism of both drugs. The effects of 0.02 microM and 0.2 microM MTX on the PDNS of MOLT-4 (T-), RAJI (B-) and KM-3 (non-B-non-T-) human malignant lymphoblasts were studied with respect to PRPP levels, aminoimidazolecarboxamide ribonucleosidemonophosphate (AICAR) levels and the incorporation of labeled glycine into purine metabolites. These results were correlated with the activity of the PDNS (labeled glycine incorporation) and the purine salvage pathway (labeled hypoxanthine incorporation) in untreated cells. Inhibition of PDNS by 0.02 microM MTX was complete in KM-3 cells with a moderately active PDNS and salvage pathway. RAJI cells, with a relatively low PDNS and high salvage pathway, demonstrated an incomplete, but increasing inhibition of PDNS, whereas inhibition of PDNS in MOLT-4 cells with both pathways active was minimal and recovered in time. Treatment with 0.2 microM MTX resulted in a complete inhibition of PDNS in all cell lines. After treatment with MTX an enhanced incorporation of labeled hypoxanthine and 6MP was noticed, confirming the potential rescue from MTX cytotoxicity by hypoxanthine and a potential synergism of MTX and 6MP on cytotoxicity. The enhanced incorporation of 6MP was more obvious in RAJI and KM-3 cells in comparison with MOLT-4 cells. These data demonstrate the important role of both the activities of the PDNS and the purine salvage pathway in malignant lymphoblasts of different subclasses with respect to the synergism of MTX and 6MP.

PMID: 2455519 [PubMed - indexed for MEDLINE]

Systemic exposure to mercaptopurine as a prognostic factor in acute lymphocytic leukemia in children.

Comment in: N Engl J Med. 1990 Nov 29;323(22):1565-6.

Koren G, Ferrazini G, Sulh H, Langevin AM, Kapelushnik J, Klein J, Giesbrecht E, Soldin S, Greenberg M.

Division of Clinical Pharmacology, Hospital for Sick Children, Toronto, ON, Canada.

BACKGROUND. Despite a success rate of more than 90 percent in inducing remission in children with acute lymphocytic leukemia, 30 to 40 percent of such children relapse. Maintenance therapy during remission usually includes oral mercaptopurine and methotrexate. Recently, wide variability in the bioavailability of oral mercaptopurine has been demonstrated, and there is concern that this may affect the risk of relapse. METHODS. To investigate whether lower systemic exposure to mercaptopurine may increase the risk of relapse in acute lymphocytic leukemia, we prospectively studied 23 children receiving maintenance therapy. On the basis of disease features, 11 were classified as being at low risk of relapse, and 12 at standard risk. Those who relapsed (n = 10) did not differ from those who did not in their mean age, hemoglobin level, mean daily dose of mercaptopurine and weekly dose of methotrexate, or the total number of days during which mercaptopurine and methotrexate therapy was interrupted. RESULTS. There was a significant difference in the mean (+/- SEM) area under the mercaptopurine concentration-time curve achieved by a dose of 1 mg of mercaptopurine per square meter of body-surface area: 1636 +/- 197 nmol per liter x minutes in those who relapsed, as compared with 2424 +/- 177 nmol per liter x minutes in those who did not (P less than 0.005). This caused a significantly lower total daily systemic exposure to mercaptopurine in those who relapsed (104,043 +/- 12,812 nmol per liter x minutes) than in those who did not (168,862 +/- 18,830 nmol per liter x minutes) (P less than 0.005). An identical tendency prevailed when patients at low risk and patients at standard risk were analyzed separately. Kaplan-Meier analysis revealed that children in whom an area under the curve of less than 1971 nmol per liter x minutes was achieved by a dose of 1 mg of mercaptopurine per square meter had a significantly poorer prognosis than those with larger areas under the curve (P less than 0.01). Similarly, those with a total daily systemic exposure of more than 137,970 nmol per liter x minutes had a significantly better prognosis than those with a lower exposure (P less than 0.005). CONCLUSIONS. Low systemic exposure to oral mercaptopurine during maintenance therapy for acute lymphocytic leukemia in childhood adversely affects prognosis. Children should be studied at the beginning of maintenance therapy to establish the pharmacokinetics of mercaptopurine, and the dose should be tailored to achieve an appropriate systemic exposure.

PMID: 2355954 [PubMed - indexed for MEDLINE]

Maintenance chemotherapy for childhood acute lymphoblastic leukemia: should dosage be guided by white blood cell counts?

Schmiegelow K, Pulczynska MK.

Department of Pediatrics, University Hospitals, Copenhagen, Denmark.

In a retrospective population-based study of 122 children with non-B-cell acute lymphoblastic leukemia (ALL), we analyzed the relation between risk of relapse and the degree of leukopenia achieved during oral methotrexate (MTX) and 6-mercaptopurine (6MP) maintenance chemotherapy (MT). After a median follow-up of 62 months for patients still in remission, 43 patients had relapsed (including 28 bone marrow relapses). Patients with a mean white blood cell count during MT (mWBCMT) of less than or equal to 3.5 x 10(9)/L had a significantly lower risk of hematological relapse (p = 0.007) as well as of any relapse (p = 0.02) compared to patients with higher mWBCMT. The clinical advantage of leukopenia could be demonstrated for all risk groups and was not explained by differences in year of diagnosis, gender, age, and white blood cell count at diagnosis, or the prescribed dose of MTX and 6MP. Although prospective studies are needed to establish the benefit of upward dose adjustments to achieve leukopenia, these results indicate a clinical advantage of keeping WBCs low during MT.

PMID: 2285127 [PubMed - indexed for MEDLINE]

Six-year experience with a comprehensive approach to the treatment of recurrent childhood acute lymphoblastic leukemia (ALL-REZ BFM 85). A relapse study of the BFM group.

Henze G, Fengler R, Hartmann R, Kornhuber B, Janka-Schaub G, Niethammer D, Riehm H.

Department of Hematology and Oncology, University Children's Hospital, Berlin, Germany.

Between April 1985 and March 1987 130 children and adolescents up to 18 years of age with first relapse of acute lymphoblastic leukemia (ALL) were registered on the stratified and randomized multicentric trial ALL-REZ BFM 85 designed for patients pretreated with intensive front-line therapies. Stratification criteria were time and site of relapse: bone marrow (BM) relapse on or up to 6 months after stopping front-line therapy (group A), BM relapse beyond 6 months after therapy (group B), and isolated extramedullary relapse at any time (group C). Treatment consisted of alternating courses of polychemotherapy including randomly administered high- or intermediate-dose methotrexate (HDMTX:12 g/m2 as 4-hour infusion; IDMTX: 1 g/m2 as 36-hour infusion). During maintenance therapy the patients received daily oral thioguanine and biweekly intravenous (IV) MTX. The overall second complete remission (CR) rate was 92% (groups A, B, and C: 88%, 92%, and 100%), and the probability of event-free survival (EFS) at 6 years is 0.31 +/- 0.04 (groups A, B, and C: 0.18 +/- 0.05, 0.30 +/- 0.07, and 0.72 +/- 0.11). HDMTX did not prove to be superior to IDMTX, which led to premature stopping of randomization. Risk factor analyses showed early relapse, particularly BM relapse within 18 months, and T-cell phenotype to be independent predictors of poor outcome. The incidence of central nervous system (CNS) relapses following BM relapse was 19%, indicating that reprophylaxis to the CNS with IV/intrathecal (IT) MTX was insufficient. For 17 children who received bone marrow transplantation in second CR from HLA-compatible siblings the EFS was 0.53 +/- 0.12 at 5 years. Their outcome was not influenced by the above-mentioned risk factors. With the proposed treatment regimen long-lasting second remissions can be achieved in about one third of patients even after intensive front-line treatment.

Publication Types: Clinical Trial Randomized Controlled Trial

PMID: 1878583 [PubMed - indexed for MEDLINE]

Prognostic significance of methotrexate and 6-mercaptopurine dosage during maintenance chemotherapy for childhood acute lymphoblastic leukemia.

Erratum in: Pediatr Hematol Oncol 1992 Apr-Jun;9(2):following 198

Schmiegelow K.

Department of Pediatrics, University Hospital, Copenhagen, Denmark.

Tolerance of full-dose methotrexate/6-mercaptopurine (MTX/6MP) maintenance therapy for childhood acute lymphoblastic leukemia (ALL) without side effects could reflect insufficient systemic drug exposure, and drug withdrawals due to toxicity might reduce the chance of cure. The present study included 122 children with non-B cell acute lymphoblastic leukemia with a median follow-up of 84 months. Leukopenia and hepatotoxicity were calculated as weighted means of all white cell counts and all serum aminotransferase measurements, respectively, registered for each patient. Forty-five patients relapsed (30 in bone marrow). Patients tolerating an average dose of MTX of more than 75% of the recommended protocol doses and having cumulated drug withdrawals of less than 1% of the period of maintenance therapy had an increased risk of hematological relapse (p = 0.008) as well as of any relapse (p = 0.03) when compared to the remaining patients. Patients with a cumulative withdrawal of MTX or of 6MP for greater than 10% of the maintenance therapy period had an increased risk of hematological relapse (MTX: p = 0.009, 6MP: p less than 0.0001) and of any relapse (MTX: p = 0.16, 6MP: p = 0.0002). Liver toxicity was the main reason for cumulative long-term drug withdrawals. However, patients with a mean aminotransferase level above the upper normal limit (40 IU/l) who were kept on therapy (cumulative withdrawals of neither drug for more than 5% of their maintenance therapy period) had a significantly lower risk of hematological relapse (p = 0.02) as well as of any relapse (p = 0.06) than the remaining children. The concept of treating to toxicity seems warranted for maintenance therapy of childhood lymphoblastic leukemia.

PMID: 1782110 [PubMed - indexed for MEDLINE]

Chronopharmacology of methotrexate pharmacokinetics in childhood leukemia.

Koren G, Ferrazzini G, Sohl H, Robieux I, Johnson D, Giesbrecht E.

Division of Clinical Pharmacology, Hospital for Sick Children, Toronto, Ontario, Canada.

Survival has been shown to improve when maintenance therapy for acute lymphocytic leukemia in children is given at night rather during the day. We examined the possibility that diurnal variation in methotrexate pharmacokinetics may contribute to this improvement. In a crossover study, we determined the pharmacokinetics of intravenous methotrexate at 10:00 and 21:00 h in six children with standard or high-risk leukemia. During the study, children refrained from concomitant drugs (6-mercaptopurine and trimethoprim sulfamethoxazole). There was a significant fall in methotrexate plasma clearance at night (from 5.6 +/- 3 ml/min/kg to 4.7 +/- 2.3 ml/min/kg p < 0.05). Renal clearance of methotrexate tended to decrease at night and unbound renal clearance decreased significantly (from 17.5 +/- 1.7 ml/min/kg to 8.5 +/- 3.6 ml/min/kg p < 0.05). Creatinine clearance did not exhibit diurnal variation, when comparing two 12-h collections, but there was a significant decrease in the nonglomerular clearance of methotrexate (from 14.8 +/- 5.2 to 6 +/- 4 ml/min/kg). Because it is a weak organic acid, the tubular secretion of methotrexate depends on urinary pH. At night urinary pH is more acidic. This may result in more reabsorption and hence reduced renal clearance.

PMID: 1473196 [PubMed - indexed for MEDLINE]

High-dose methotrexate administration and acute liver damage in children treated for acute lymphoblastic leukemia. A prospective study.

Locasciulli A, Mura R, Fraschini D, Gornati G, Scovena E, Gervasoni A, Uderzo C, Masera G.

Clinica Pediatrica, Universita di Milano, Ospedale S. Gerardo, Monza, Italy.

BACKGROUND. Methotrexate-induced hepatotoxicity following chronic low-dose administration has been extensively reported. Current protocols now include high-dose methotrexate (HDMTX), but there are few studies providing data on its acute hepatotoxicity in childhood leukemia. METHODS. To evaluate the prevalence of HDMTX-induced acute hepatotoxicity, sixty-eight consecutive children with ALL were prospectively studied from diagnosis to the end of HDMTX courses with biochemical and clinical evaluation performed at regular intervals. RESULTS. Prevalence of HDMTX-induced acute hepatotoxicity was 1.47% (1/68 patients). ALT values did not change in 22% (15/68) and decreased in 76.4% (52/68) after HDMTX infusion. Mean ALT levels calculated in all the patients decreased significantly during HDMTX administration when compared to the values reached during induction (p less than 0.0001). Direct hyperbilirubinemia was present only in the child with HDMTX-related hepatotoxicity. CONCLUSIONS. The use of HDMTX in the treatment of childhood ALL is not associated with major evidence of direct acute hepatotoxic effects, while it may modify the pattern of preexisting liver diseases.

PMID: 1398282 [PubMed - indexed for MEDLINE]

On the biochemical modulation of 6-mercaptopurine by methotrexate in murine WEHI-3b leukemia cells in vitro.

Liliemark J, Pettersson B, Peterson C.

Department of Medicine, Karolinska Institute, Huddinge Hospital, Stockholm, Sweden.

The chemicals 6-mercaptopurine (6-MP) and methotrexate (MTX) are the cornerstones in the maintenance treatment of acute lymphoblastic leukemia. The intracellular metabolism of 6-MP to 6-thioguanosine nucleotides (TGN) via 6-thioinosine 5'-monophosphate (TIMP) is crucial for its cytotoxic effect. MTX inhibits purine de novo synthesis and thereby increases the intracellular PRPP being a substrate for the phosphoribosylation of 6-MP to TIMP. Hypoxanthine has been shown to inhibit the uptake of 6-MP over the cell membrane and the phosphoribosylation of 6-MP to TIMP. We have previously shown that the conversion of TIMP to TGN decreases at 6-MP concentrations above 5 microM in vitro. The aim of the present study was therefore to investigate the effect of MTX increasing the PRPP and TIMP concentrations and of hypoxanthine decreasing the TIMP concentration on the formation of TGN from TIMP. Murine myelomonocytic leukemia cells (WEHI-3b) were treated with 6-MP in vitro. The drug concentration was kept constant by continuous addition of 6-MP during the experiment. With this technique, the concentration of TGN begins to decrease already at 6-MP concentrations above 2 microM. The addition of 0.2 microM MTX 6 h before 6-MP strongly inhibited the purine de novo synthesis, decreased the ATP, and increased the PRPP concentration 4-fold. The intracellular concentrations of TIMP and to a lesser extent TXMP also increased. The concentrations of the TGN were, however, basically unaffected by the preincubation with MTX. Simultaneous addition of 20-50 microM hypoxanthine and 6-MP decreased the accumulation of all cellular 6-MP metabolites. It is concluded that the synergistic cytotoxic effect of the combination of 6-MP and MTX is not based on biochemical modulation of the 6-MP metabolism by MTX.

PMID: 1373210 [PubMed - indexed for MEDLINE]