High cure rate with a moderately intensive treatment regimen in non-high-risk childhood acute lymphoblastic leukemia. Results of protocol ALL VI from the Dutch Childhood Leukemia Study Group.

PURPOSE: Here we report the results of a nationwide cooperative study in the Netherlands on acute lymphoblastic leukemia (ALL) in children. The aim of the study was to improve the cure rate and to minimize side effects in a group of non-high-risk ALL patients, especially with regard to the CNS. A second aim was to study potential prognostic factors. METHODS: Children (age 0 to 15 years) with non-high-risk ALL (WBC count < 50 x 10(9)/L, no mediastinal mass, no B-cell phenotype, and no CNS involvement) were treated with a uniform protocol, ALL VI. The treatment protocol used 6-week induction regimen with three drugs (vincristine, dexamethasone, and asparaginase), three weekly doses of intravenous (IV) medium high-dose methotrexate (2 g/m2), and 2-year maintenance therapy that consisted of alternating 5-week periods of methotrexate and mercaptopurine and 2-week periods of vincristine and dexamethasone. In the first year of maintenance, triple intrathecal therapy was administered every 7 weeks. RESULTS: From December 1, 1984 until July 1, 1988, 291 children with ALL were diagnosed; 206 were categorized as non-high-risk (71%), and 190 were treated according to protocol ALL VI. At 8 years, the event-free survival (EFS) rate was 81% (SE = 3%) and survival rate 85% (SE = 2.9%); the median follow-up time was 7.3 years (range, 36 to 117 months). The CNS relapse rate was 1.1% (two of 184 patients who achieved a complete remission [CR]). The only factor found to be of negative prognostic importance in terms of EFS (P = .05) was a positive acid phosphatase reaction. CONCLUSION: For children with non-high-risk ALL, the combination of IV medium high-dose methotrexate (2 g/m2 times three), triple intrathecal therapy in the first year of maintenance treatment, and the use of dexamethasone for induction and pulses during maintenance treatment has proved to be highly effective, especially in the prevention of CNS relapse. A high cure rate was achieved without the use of anthracyclines, alkylating agents, and cranial irradiation.

Dose-related effects of methotrexate on purine and pyrimidine nucleotides and on cell-kinetic parameters in MOLT-4 malignant human T-lymphoblasts.

The effects of methotrexate (MTX) on cytotoxicity (trypan blue exclusion and soft agar clonal growth), cell cycle perturbation, and purine and pyrimidine ribonucleotide and deoxyribonucleotide pools have been studied in MOLT-4 malignant T-lymphoblasts. Two concentrations of MTX, 0.02 microM and 0.2 microM have been utilized, which can be maintained in vivo during many hours in the maintenance therapy of acute lymphoblastic leukemia (ALL). The results are correlated with the effects of MTX on the inhibition of purine de novo synthesis. Treatment with 0.02 microM MTX results in an accumulation of cells in early S phase after 20 hr, as measured by DNA flow cytometry and by a significant increase of dCTP levels, followed by a slow progression of a cohort of cells through the cell cycle. Cytotoxicity also becomes evident starting from this point of time. The effects on deoxyribonucleotide pools are discussed in correlation with the inhibition of DNA synthesis. The changes in ribonucleotide pools are associated with the partial inhibition of purine de novo synthesis at 20-28 hr and suggest an inhibition of RNA synthesis. After 48 hr a reutilization of nucleotide precursors due to nucleic acid breakdown and a recovery of purine de novo synthesis is shown, associated with a recovery of RNA synthesis, whereas cytotoxicity increases. Treatment of MOLT-4 cells with 0.2 microM MTX results in a rapid complete cessation of cell progression through all parts of the cell cycle after 8 hr, associated with a depletion of all deoxyribonucleotide pools, complete inhibition of purine de novo synthesis, inhibition of RNA synthesis and a marked cytotoxicity. Ribonucleotide pools demonstrate a reutilization of nucleotide precursors after 12 hr of incubation without a recovery of purine de novo synthesis and RNA synthesis. These data show a close dose- and time-dependent correlation of the effects of MTX on purine de novo synthesis, UMP levels and other (deoxy)ribonucleotide pools, and on RNA and DNA synthesis in MOLT-4 cells having an active purine de novo synthesis. This correlation is absent in normal bone marrow cells and peripheral blood lymphocytes. These data can be used in order to elucidate the synergistic effects of sequential administration of MTX and 6-mercaptopurine.

6-Thioguanine: high-dose 2-H infusions in goats.

6-Thioguanine (6TG) is poorly absorbed after oral administration. Bolus injections of 6TG result in high peak concentrations with relatively short-lived plasma concentrations. In vitro studies have shown the importance of prolonged exposure to 6TG. Therefore we administered 6TG by infusion at a dose rate of 2 mg/h over 2 h. In three goats we determined the plasma concentration-time curves of 6TG and its riboside (6TGR). A steady state was reached for 6TG and was almost reached for 6TGR within the 2 h of infusion. In one experiment we obtained several samples of CSF and observed good penetration of 6TG and 6TGR into CSF. Urinary excretion of 6TG and 6TGR was also quantitated. The amount of drug and metabolite excreted later than 4 h after the end of the infusion was negligible. By infusing 6TG, the problems of both erratic absorption after oral administration and acute renal toxicity after bolus injection, can be averted. In our opinion prolonged infusions of 6TG may be of advantage in humans suffering from actively proliferating malignant diseases, and thus should be studied.

6-mercaptopurine: high-dose 24-h infusions in goats.

In vitro investigations have indicated the need for both prolonged exposure to 6-mercaptopurine (6MP) and the use of high concentrations to achieve maximal cell kill. After the customary oral administration the bioavailability of 6MP appeared to be low, and i.v. bolus injections resulted in short-lived high concentrations of 6MP, so prolonged infusions seemed rational. To test the feasibility of this approach 24-h infusions were given to goats. We used our improved HPLC method to quantitate 6MP and 6MP riboside (6MPR) in plasma, CSF, and urine. The concentrations of 6MPR were in excess of those of 6MP. Since 6MPR can easily be converted to 6MP, 6MPR acts as a depot for 6MP. Penetration of both 6MP and 6MPR into CSF was excellent. Of the total dose administered, 38% to 68% could be accounted for in the urine, with about equal amounts of 6MP and 6MPR. At doses of 20 and 10 mg kg-1 h-1 total concentrations of 6MP and 6MPR in excess of 100 microM were reached during 24-h infusions. However, all three experimental animals died due to toxicity. A dose of 2 mg kg-1 h-1 was tolerated; the total steady state concentration of 6MP and 6MPR in two experiments was about 10 microM. We conclude that the prolonged infusion of 6MP is feasible, and in view of the excellent penetration of 6MP and 6MPR into CSF, studies using prolonged infusions of thiopurines are warranted in man.

Neurocristopathy in mother (ganglioneuroblastoma) and daughter (aganglionosis): incidental or causal?

We report on a mother who had been treated for a ganglioneuroblastoma and her daughter who had a long segment aganglionosis. Review of the relevant literature and recent molecular findings warrant the conclusion that most likely, there is a causal relation between these two neurocristopathies.

[Extramedullary leukemia]. / Beschouwingen over extramedullaire leukemie.

Leukemia is primarily a bone marrow disease. Secondary invasion in other tissues usually disappears after a successful remission induction. Leukemic cells may remain in undetectable numbers in gonads and central nervous system (CNS). These sites are shielded from infiltration by cytostatics, this shielding however is far from absolute. Ovarian leukemia is extremely rare, testicular leukemia is relatively rare. Prophylactic measures (radiotherapy, biopsies) are therefore not warranted. In case of testicular leukemia bilateral biopsies, greater than 2000 Rad irradiation and a reinduction treatment are advised. CNS-leukemia-prophylaxis and treatment should be effective, i.e. complete eradication is the goal, but treatment-strategies should aim at minimizing lasting CNS-damage. The type of treatment given should be tailored to the patient: in non high risk ALL prophylaxis without irradiation is feasible, in T-cell-leukemia and NHR-ALL with initial CNS-leukemia a plea is made for craniospinal irradiation in the prophylaxis scheme. The use of Ommayadrains should be considered.

[Severe anemia caused by transient erythroblastopenia in young children]. / Ernstige anemie door een tijdelijke erytroblastopenie bij jonge kinderen (TEK).

In the period 1975-1981 seventeen patients aged from 4 to 30 months were seen with transient normochromic, normocytic anemia and reticulocytopenia caused by erythroblastopenia. The majority of the cases (12/17) were seen in autumn and winter. In 16 of the patients bone marrow aspirates were obtained; they showed erythroblastopenia. In 7 cases we observed young lymphoïd cells, which suggested the diagnosis of leukemia. Distinguishing features of congenital hypoplastic anemia and transient erythroblastopenia of childhood are compared. Except for blood transfusion, therapy e.g. corticosteroïds is not necessary in transient erythroblastopenia of childhood. Spontaneous recovery is a diagnostic feature, contrasting with congenital hypoplastic anemia.

[Biochemical and clinico-pharmacological aspects of antimetabolites in the treatment of leukemia]. / Biochemisch- en klinisch-farmacologische aspecten van antimetabolieten bij de behandeling van leukemie.

Methotrexate (MTX) and 6-mercaptopurine (6MP) have been used since 30 years in the maintenance treatment of acute lymphoblastic leukemia (ALL) of childhood. A synergistic effect of this combination was demonstrated in mouse and childhood leukemia. In this article an overview is given of our investigations, concerning the biochemical basis of this synergism. This synergism is caused by a selective inhibition of the purine de novo synthesis in malignant lymphoblasts by MTX, associated with an enhanced intracellular uptake of 6MP. Pharmacokinetic studies of MTX in various schemes of prophylactic central nervous system treatment in ALL are discussed. Treatment with 24-hr infusions of MTX in a dosage of 5 g/m2, as recommended in the new BFM-86/SNWLK ALL VII protocol, seems to be optimal. Pharmacokinetic studies of intravenous 6MP infusions demonstrated a good cerebral fluid penetration. Exploiting the synergistic action of the combination of MTX and 6MP may offer an improvement of the prophylactic central nervous systems treatment in ALL in the future, using intravenous administration of both MTX and 6MP.

[6-Mercaptopurine and methotrexate, rational use in sight after 35 years?]. / 6-Mercaptopurine en methotrexaat, zicht op een rationeel gebruik na 35 jaar?

A survey is given of our present investigations of the pharmacokinetics of 6MP and the effects of the combination of MTX and 6MP on purine and pyrimidine metabolism. Both drugs are used in the oral maintenance therapy of ALL in children. The very low serum-concentrations after oral administration of 6MP and the short serum-half-life-times after intravenous administration point to more efficacy after prolonged intravenous infusion. The penetration of 6MP in the cerebrospinal fluid after intravenous administration could account for (prophylactic) treatment of the CNS in ALL. Pretreatment of leukemic lymphoblasts with MTX results in an increase of intracellular PRPP due to inhibition of purine de novo synthesis. This can be used for an increased incorporation and conversion of 6MP. Thus, increased incorporation and conversion of 6MP can be obtained when 6MP is added to MTX-pretreated leukemic lymphoblasts at that point of time where MTX causes maximal PRPP accumulation. This will result in increased incorporation of 6MP into nucleic acids and thus in enhanced cytotoxicity. Pharmacokinetic and metabolic investigations of 6MP and MTX could lead to a more rational and more effective use of both agents in patients with ALL.

Mild course of mumps in patients with acute lymphoblastic leukaemia.

Few details exist on the course of mumps during cytostatic treatment. We therefore describe our observations on the course of mumps seen between 1974 and 1988 in eight children suffering from acute lymphocytic leukaemia (ALL). Our data suggest that in malignant disease the course is rarely severe and that the infection often remains subclinical, as in healthy children. Mumps was accidentally diagnosed by routine lumbar puncture in four of the eight patients. Literature data suggest that the intrinsic low cytopathological effect of the virus, together with a parallelism between T cell response and clinical severity, may explain the usual mild course in immunodepressed patients, contrasting with the severe course of measles and Varicella zoster.

Hypereosinophilia syndrome or eosinophilic leukaemia. A case report of a one-year-old infant.

The case history of a one-year-old girl, who suffered from a fatal hypereosinophilia syndrome (HES), is presented. It is demonstrated that in this particular patient the origin of the HES has been a variant type of juvenile chronic myeloid leukemia. Clinical and pathologic data are presented. This is the youngest patient ever described as having suffered from fatal HES caused by a leukemic process.

Utility of density gradient centrifugation for fractionation of leukemic bone marrow.

Comparison of the distribution pattern of leukemic and normal bone marrow cells, obtained by density gradient centrifugation, may give information about the location of the blockade in the differentiation pathway from stem cell to mature leukocyte, as is supposed to exist in acute leukemia. As a control group 12 children with acute lymphoblastic leukemia (ALL), in complete remission and after cessation of all antileukemic therapy, were studied. By centrifugation over a discontinuous bovine serum albumin (BSA) density gradient, good reproducibility of the partition of the bone marrow cell population was obtained, with a peak in the more dense region. The cells capable of incorporation of [3H] thymidine in vitro were present predominantly in the lower density range. In 9 patients with lympho- or myeloproliferative malignancies (3 with o-cell ALL, 2 with T-cell malignant lymphoma, 1 with B-cell malignant lymphoma, 3 with various malignancies of the myeloid-monocytoid series) similar fractionation on the BSA gradient revealed a different cell partition pattern as compared with the control group. The peak of the distribution curve was located in the less dense region. Highest [3H] thymidine incorporation values were measured in vitro with cells from the lower density region. At last the importance of purely practical considerations in the choice of material for density gradient fractionation is stressed. Application of density gradient centrifugation methods could probably be helpful in attributing to cells from acute leukemia a place in the normal differentiation pathway.