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Biomedical subjects

P Steuber

Publications and source records attributed to P Steuber.

12 recordsLinked to original sources
PubMed1996

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.

Adolescent↗
PubMed1994

Intensive intravenous methotrexate and mercaptopurine treatment of higher-risk non-T, non-B acute lymphocytic leukemia: A Pediatric Oncology Group study.

PURPOSE: To determine the potential efficacy and toxicity of intravenous (i.v.) methotrexate (MTX) and mercaptopurine (MP) as postremission intensification treatment for children with B-lineage acute lymphoblastic leukemia (ALL) at higher risk to relapse. PATIENTS AND METHODS: Eighty-three patients (age 1 to 20 years) with higher-risk B-lineage ALL were entered onto this protocol. Following standard four-drug remission induction, 80 patients received 12 intensive 2-week cycles of MTX/MP: MTX 200 mg/m2 i.v. push, then 800 mg/m2 i.v. 24-hour infusion on day 1; MP 200 mg/m2 i.v. in 20 minutes, then 800 mg/m2 i.v. 8-hour infusion day 2; MTX 20 mg/m2 intramuscularly day 8; and MP 50 mg/m2 by mouth days 8 to 14. Age-based triple intrathecal therapy (MTX, hydrocortisone, and cytarabine) was administered for CNS prophylaxis. Continuation therapy was weekly MTX/MP (as on days 8 to 14) for 2 years. RESULTS: Eighty-one patients (98%) entered remission. There were 28 relapses (marrow, n = 11; marrow and CNS, n = 2; isolated CNS, n = 9; testes, n = 5; ovaries, n = 1). No overt relapse occurred during the intensive phase of therapy. The event-free survival (EFS) rate at 4 years is 57.4% +/- 9.1% (SE). Hematologic, mucosal, and infectious toxicities were seen in 12%, 9%, and 5% of intensive MTX/MP courses, but were generally mild. CONCLUSION: Combined data from this and our previous trial suggest that intensive MTX/MP may produce long-term disease-free survival in 70 to 75% of children with B-lineage ALL. In comparison to other intensive regimens, intensive MTX/MP is easy to administer, effective, and relatively nontoxic. If patients at risk for failure of MTX/MP can be identified prospectively, more aggressive regimens could be restricted to this smaller (25% to 30%) cohort.

Adolescent↗
PubMed1993

Transitional pre-B-cell acute lymphoblastic leukemia of childhood is associated with favorable prognostic clinical features and an excellent outcome: a Pediatric Oncology Group study.

The presenting characteristics and survival of children with the newly recognized transitional cell pre-B immunophenotype of acute lymphoblastic leukemia (ALL) are compared with those of children with pre-B ALL to determine the clinical significance of the new phenotype. Patients with transitional pre-B ALL (n = 17), defined by lymphoblasts expressing cytoplasmic and surface mu heavy chains without kappa or lambda light chains, have lower initial leukocyte counts (p = 0.02) and a higher frequency of DNA indexes > 1.16 (p < 0.001) than patients with pre-B ALL (n = 501), whether or not cases with the unfavorable prognostic (1;19) translocation are included in the analysis. Patients with transitional pre-B ALL lack FAB L3 morphology, bulky extramedullary disease, surface kappa or lambda chains, and the (8;14), (8;22), and (2;8) translocations, features that characterize the syndrome of B-cell ALL. The 4-year relapse-free survival result for children with transitional pre-B ALL appears better than that for children with pre-B ALL (93.3 +/- 17% versus 72.9% +/- 4.6%), but this difference is not statistically significant. We conclude that patients with transitional pre-B ALL have a very favorable prognosis in the context of the therapy used in this study.

Adolescent↗
PubMed1992

Current results of studies of immunophenotype-, age- and leukocyte-based therapy for children with acute lymphoblastic leukemia. The Pediatric Oncology Group.

From February 1986 to January 1991 the Pediatric Oncology Group (POG) treated 2404 children or adolescents with acute lymphoblastic leukemia (ALL) on immunophenotype (T-, B-, Pre-B, or Early pre-B-cell), age, and leukocyte count based treatment protocols (ALinC 14, T-cell 3, B-cell and infant leukemia studies). The immunophenotypic subgroups comprised 78.9% B-precursor cell, 15.1% T-cell, 2.0% B-cell, and 4% infant ALL. Patients with B-progenitor cell ALL were stratified by age and leukocyte count and randomized to receive induction therapy comprised of vincristine, prednisone, and asparaginase with triple intrathecal chemotherapy (methotrexate, hydrocortisone, cytarabine), followed by intensification with moderate-dose MTX (Regimen A), moderate-dose MTX plus asparaginase (Regimen B), moderate-dose MTX plus cytarabine given early (Regimen C), or moderate-dose MTX plus cytarabine given over the first 16 months of therapy (Regimen D). Continuation therapy comprised mercaptopurine and methotrexate with vincristine plus prednisone pulses. Central nervous system preventive treatment was continued for two years. Patients with T-cell or B-cell ALL or infants less than 1 yr old were treated on individual very intensive multiagent therapy protocols. The 4-year event-free survival for all patients was 66.4% +/- 2.4%; B-precursor ALL approximately 72%, T-ALL approximately 50%, B-ALL approximately 60%, and infants less than 1 yr old approximately 16.5%. We conclude that about two-thirds of newly diagnosed children with ALL can be cured with this approach which spares the majority of children exposure to alkylating agents, anthracyclines, epipodophylotoxins, and irradiation, diminishing the risks of serious acute and late effects.

Adolescent↗
PubMed1990

Philadelphia chromosome positive childhood acute lymphoblastic leukemia: clinical and cytogenetic characteristics and treatment outcome. A Pediatric Oncology Group study.

Among 3,638 children with acute lymphoblastic leukemia (ALL) entered on Pediatric Oncology Group (POG) protocols between June 1981 and April 1989, successful cytogenetic studies were available for 2,519, 58 (2.3%) of which had the Philadelphia (Ph) chromosome detected. Features associated with the presence of the Ph chromosome were high leukocyte count (median, 33 x 10(9)/L), older age median, 9.6 years), a higher proportion of French-American-British L2 morphology, and a lower frequency of mediastinal mass. Immunologic marker studies at diagnosis in 56 Ph+ cases identified early pre-B ALL in 42 cases (75%), pre-B-cell in 9 (16%), and T-cell in 5 (9%). This distribution is similar to that found in Ph+ ALL. Intensive multiagent chemotherapy induced complete remissions in only 78% of eligible Ph+ patients compared with 96% of those without an identified Ph chromosome (P less than .001). Of 44 eligible Ph+ patients treated on POG frontline protocols for children with non-T, non-B-cell ALL, 27 have failed therapy, compared with 520 of 1,892 without an identified Ph chromosome (logrank P less than .001). Ph+ ALL is an aggressive form of acute leukemia that frequently presents in older children with a high leukocyte count, FAB L2 morphology, and a pseudodiploid karyotype, and becomes multidrug-resistant early. Thus, Ph+ cases require early identification to permit treatment with intensive induction regimens and experimental approaches such as bone marrow transplantation.

Asparaginase↗
PubMed1990

RAS gene mutations in childhood acute myeloid leukemia: a Pediatric Oncology Group study.

Mutations at codon 12, 13, and 61 of the HRAS, KRAS, and NRAS genes were evaluated in 99 cases of pediatric acute myeloid leukemia (AML) using oligonucleotide hybridization to polymerase chain reacted derived products. Twenty-four mutations were identified in the NRAS gene, 13 in the KRAS gene, and none in the HRAS gene. The mutations occurred in a broad spectrum of cases, and there was no specific association of RAS gene mutations with patient subsets defined on the basis of clinical or hematologic features. These data demonstrate that RAS gene mutations are at least as common in childhood AML as in adult AML and suggest that RAS gene mutations play a role in myeloid neoplasia in both age groups.

Adolescent↗
PubMed1984

Combination chemotherapy with vincristine (NSC-67574), procarbazine (NSC-77213), prednisone (NSC-10023) with or without nitrogen mustard (NSC-762)(MOPP vs OPP) in children with recurrent brain tumors.

Seventy-three patients under 18 years of age with a recurrent central nervous system tumor were randomized to receive combination chemotherapy with MOPP or OPP. Patients were stratified according to the tumor type into four major disease categories: (1) medulloblastoma, (2) astrocytoma and other glioma, (3) ependymoma, and (4) miscellaneous tumors to provide equal distribution of patients for each treatment within each disease category. Evaluation of response was based on computerized brain scan findings. Thirty-five patients received MOPP and 38 received OPP treatment. There were three complete and six partial remissions among patients receiving MOPP and one complete and five partial remissions among patients receiving OPP. In addition, six patients on MOPP had stable disease for seven to 21 months. Only two patients on OPP had stable disease(6 and 36 months). Most of responses in both treatment regimens occurred in patients with medulloblastoma and astrocytoma. Median duration of remission was nine months for the MOPP and 11 months for the OPP. Two patients on MOPP regimen had fatal myelosuppression. Although the more toxic MOPP regimen produced more responses than OPP in children, differences in the duration of response or survival were not statistically significant (P = .79 and P = .84, respectively).

Adolescent↗
PubMed1981

Trial of daunomycin in acute promyelocytic leukemia of childhood: a Southwest Oncology Group Study.

Children with acute promyelocytic leukemia were treated with aggressive daunomycin induction and 6-mercaptopurine and methotrexate maintenance. The remission rate was 8 out of 10 fully evaluable patients. Three are still alive up to 32 months. With vigorous induction therapy, occurrence of disseminated intravascular coagulation was rare. Only one case of DIC was seen in a child who had pseudomonas sepsis at time of diagnosis. Since current protocols are more aggressive, future chemotherapy include patients with acute promyelocytic leukemia.

Adolescent↗
PubMed1976

Acute leukemia in Burkitt lymphoma.

Burkitt lymphoma uncommonly presents as a acute leukemia. We describe the clinical course and findings of a 14-year-old female with Burkitt lymphoma who presented with acute leukemia. splenomegaly and an abdominal mass. She responded initially to prednisone alone and later achieved full remission with combination chemotherapy. Established morphologic criteria and clinical course were consistent with the diagnosis of Burkitt lymphoma (1), although B-cell determinants were not present on her tumor cells.

Abdominal Neoplasms↗