Changes in red blood cell methotrexate pharmacology and their impact on outcome when cytarabine is infused with methotrexate in the treatment of acute lymphocytic leukemia in children: a pediatric oncology group study

Since it is unclear whether methotrexate and cytarabine are synergistic or antagonistic in the treatment of acute lymphoblastic leukemia, the Pediatric Oncology Group studied the prognostic significance of a potential interaction between these agents. RBC methotrexate concentrations were compared from 140 patients at lower risk of relapse randomized to two treatment groups: one receiving six methotrexate infusions with overlapping cytarabine; the other, six methotrexate infusions alone. Samples from 248 patients from all risk groups were studied to determine whether patients with extremely low RBC methotrexate concentrations had inferior outcomes. Among low-risk patients studied 3 weeks after the sixth infusion, median RBC methotrexate concentrations were 0.13 nmol/ml RBCs (n = 71) for the methotrexate-only group and 0.02 nmol/ml RBCs (n = 69) for the methotrexate/cytarabine-treated low-risk patients, P < 0.001 by the two-sided Wilcoxon test. For low- and high-risk patients receiving methotrexate/cytarabine infusions, event-free survival at 1 and 3 years after RBC sampling was 97 +/- 2% and 90 +/- 3% for patients with concentrations greater than the median, and 88 +/- 3% and 78 +/- 4% for those with concentrations at or below the median. Log rank comparisons of event-free survival in the first year and overall yielded P = 0.005 and P = 0.04, respectively. Cytarabine altered methotrexate pharmacology when the drugs were infused together. Patients whose levels were extremely low had an adverse prognosis. Although this study could not assess efficacy of the methotrexate/cytarabine combination, it appears that concurrent administration is not optimal.

Ethnicity and cure rates of Texas children with acute lymphoid leukemia

BACKGROUND

Ethnic differences in the survival of children treated for acute lymphoid leukemia (ALL) have been described in several locations. Children of African, Polynesian, Native American, and Mexican ancestry had a less favorable outcome than children of European ancestry when treated in a similar manner by the same physicians and nurses.

METHODS

We reviewed the medical records of the 94 European-American (E-A) and 84 Mexican-American (M-A) Texas children registered and treated in national collaborative ALL therapy trials at the M. D. Anderson Cancer Center in Houston between 1974 and 1985 and followed through June 1994. Information was collected regarding age, sex, presenting clinical features, risk for relapse grouping, protocol assignment, event free survival, and the financial status of their families. Cure was defined as initial continuous complete remission for more than seven years and cessation of therapy for more than four years. Presenting characteristics of E-A and M-A children were compared, and then related to cure rates by univariate and multivariate analyses. Event free survival rates of E-A and M-A children were determined together and by sex.

RESULTS

Comparing presenting features, financial status as identified by pay code was significantly less for M-A children. Other features were not significantly different. By univariate analysis, an age of 2 to 6 years, female sex, initial white blood cell count below 10,000/microL, low risk grouping, registration on the most recent protocol, and full pay status were significantly associated with higher cure rates. By multivariate analysis, male gender, high risk group, and registration on earlier protocols were found to be significantly associated with a low cure rate. Event free survival and cure rate were lower for M-A children, but the differences were not statistically significant.

CONCLUSIONS

Further study of larger numbers of patients, including contemporary immunophenotypic and genotypic characterization of ALL, is needed for better definition of possible ethnic differences. Ethnicity and financial status should be included in the analysis of clinical trials of ALL therapy.

Persistence of self-renewing leukemia cell progenitors during remission in children with B-precursor acute lymphoblastic leukemia

No effective therapy is available for the majority of the 30-40% of children with acute lymphoblastic leukemia (ALL) who relapse. Since the morphologically undetectable, or occult, leukemia cells that persist during remission originate from the clone present at diagnosis, may also have both the capability to sustain the disease and to give rise to relapse, we are evaluating a method of identifying them. We have combined, for the first time, an ALL blast colony assay (BCA) and the polymerase chain reaction (PCR) to isolate residual leukemia cells in remission bone marrow aspirate specimens from eight patients with B-precursor ALL during early continuation therapy. We found colony-forming leukemia cells with in vitro self-renewal capability that survived chemotherapy for 15 months after diagnosis in all sequential specimens from these patients. To verify the leukemic nature of these cells their DNA was amplified by PCR and the product directly sequenced. In every case, the VHDJH sequence observed at diagnosis was found. None of the patients relapsed during this early phase of their treatment, consistent with the observation that patients with B-precursor ALL experience recurrence late in their course. Since it is possible that some of these persistent leukemia cells belong to the leukemia progenitor cell population that sustains the disease, the study of them could provide the means to determine the mechanisms of relapse.

Response to alpha-interferon in children with Philadelphia chromosome-positive chronic myelocytic leukemia

The therapeutic efficacy and toxicity of alpha-interferon (alpha-IFN) (Roferon, Hoffmann-La Roche, Inc., Nutley, NJ) were determined in 15 children (age range, 6 to 20 years) with Philadelphia chromosome-positive chronic myelocytic leukemia (Ph+ CML). All patients had received cytoreductive therapy with either hydroxyurea (n = 13) or busulfan (n = 1) or both (n = 1) for 6 weeks to 46 months (median, 7 months) before beginning alpha-IFN therapy at a dose of 5 x 10(6) U/m2/d intramuscularly. This dose was escalated to 10 x 10(6) U/m2/d if leukemia was inadequately controlled. Ten children had a hematologic response, with nine showing a reduction in the percentage of Ph+ marrow cells, including four who had no detectable Ph+ cells in marrow samples collected 48 to 204 weeks after the initiation of therapy. Two of 15 patients remain free of Ph+ cells. Therapy was discontinued before week 104 in ten patients because of the following: (1) early hematologic responses without a decrease in Ph+ cells (three patients); (2) early resistant disease (one patient); (3) blast crisis (one patient); (4) progressive disease (two patients); (5) seizure attributed to high-dose alpha-IFN (one patient); or (6) an inadequate trial of alpha-IFN caused by aseptic necrosis or poor compliance (two patients). The most common side effects were mild and have included fever, malaise, headache, myalgias, and pain at the injection site. Adverse events causing interruption of therapy were seizures, aseptic necrosis, and myelofibrosis. alpha-IFN stabilizes the chronic phase of Ph+ CML in some children, is adequately tolerated when administered at a dose of 2.5 to 5 x 10(6) U/m2/d intramuscularly, and results in a significant decrease in the proportion of Ph+ metaphases in some patients. alpha-IFN in combination with an effective cytoreductive agent or agents appears worthy of further clinical testing in this disease.

Differentiation in B-precursor acute lymphoblastic leukemia cell populations with CD34-positive subpopulations

B-precursor acute lymphoblastic leukemia bone marrow specimens that contained subpopulations of cells with immunophenotypes corresponding to early (CD34) and late (CD20) and (CD22) stages of normal B-cell differentiation were studied. Subpopulations of cells were isolated according to immunophenotype and then analyzed by both a clonogenic assay and molecular genetic methods. Clonal equivalence of the early and late immunophenotypic subpopulations was confirmed for each case by the demonstration of identical lg gene rearrangements. The in vitro colony-forming assay consistently showed a growth advantage for the CD34+ subpopulations over the CD34- subpopulations. CD34 mRNA was detected readily in these isolated precursor cells. When two specimens in which virtually all of the leukemia cells were CD34+ and CD34+CD20+ and CD34+CD22+ subpopulations were also present the CD34 mRNA was limited to the cells without the late-stage differentiation antigens on their surface. Furthermore, the c-myb mRNA was found only in the subpopulations that also contained CD34 mRNA. Our results show that a limited program of differentiation reminiscent of normal B-cell development may be present in this leukemia.

8;20 chromosomal translocation in a case of acute leukemia. Cytogenetic, immunophenotypic, ultrastructural, and molecular characteristics

An 8;20 chromosomal translocation was observed in the leukemia cells of a 3-year-old girl. To our knowledge, this is the first report of this translocation in de novo acute leukemia. This chromosomal defect was present in the leukemia cells at diagnosis and also at relapse, but remission bone marrow cells had the 46,XX karyotype. By morphologic and cytochemical criteria the leukemia was myeloid but these features were more lymphoid when the leukemia recurred. However, the immunophenotype was consistent with myeloid leukemia and did not change at relapse. No evidence for either immunoglobulin or TCR gene rearrangement was observed.

Mandibular chloroma demonstrated by magnetic resonance imaging

A case of chloroma or granulocytic sarcoma in the mandible of a young child is presented with magnetic resonance imaging (MRI) features.

Mutagen sensitivity and cancer susceptibility. Report of a cancer-prone family

A cancer-prone family was studied to determine if certain chromosomal abnormalities might have predisposed members to develop diverse types of malignancies. The types of neoplasia that occurred in this family included cancers of the breast and stomach, multiple myeloma, dermatofibrosarcoma, Wilm's tumor, and leukemia; the latter three occurred in children at an early age. Peripheral lymphocytes from 13 family members were examined for the presence of constitutional chromosomal abnormalities, fragile sites, and mutagen sensitivity. Our data shows that all living members of this family who had cancers were hypersensitive to chromosome breakage induced by bleomycin. In contrast, neither constitutional chromosomal abnormality nor heritable type of folate-sensitive fragile site was observed in any member. The above findings suggest that genetic defects affecting chromosomal breakage and repair may be contributing factors for cancer development in several members of this family.

Childhood acute lymphocytic leukemia: study VIII

This controlled study of children with ALL was designed to test the efficacy and toxicity of one-, two-, three- and four-drug therapy during remission and whether more aggressive therapy in the first eight weeks prolongs remission in patients with features associated with a particularly poor prognosis. After inducing remission with prednisone, vincristine and asparaginase, patients received cranial irradiation and IT methotrexate and were randomized to receive: 1--methotrexate alone; 2--methotrexate plus mercaptopurine; 3--same as in group 2 plus cyclophosphamide; and 4--same as in group 3 plus arabinosyl cytosine. Patients with CNS leukemia at diagnosis received IT methotrexate weekly during the induction period and a higher dose of CNS irradiation. Patients with anterior mediastinal enlargement at diagnosis received radiotherapy to the mass during the induction period. Patients who failed to attain bone marrow remission after four weeks of therapy were given daunorubicin and prednisone for 2--4 additional weeks. Of the 282 patients entering this study between January 1972 and November 1975, 268 (95%) attained complete remission and 228 (85%) were randomized to receive continuation chemotherapy with 1, 2, 3 or 4 drugs. In Group 1 (methotrexate alone), 14 of 20 patients relapsed and 9 developed leukoencephalopathy without antecedent CNS leukemia apparently due to higher doses of intravenous methotrexate; in Groups 2, 3 and 4 the results were equivalent, but without leukoencephalopathy in initial CR. The addition of cyclophosphamide and arabinosyl cytosine increased toxicity and complications without demonstrably increasing the leukemocidal effect. In the 40 patients given additional early therapy, the modalties employed in this study did not prolong remission.