Cell wall composition and virulence in Escherichia coli.

Uridine diphosphate galactose 4-epimerase and phosphomannose isomerase-deficient mutants of Escherichia coli O111:B4 were studied to test the hypothesis that in E. coli a specific relationship exists between O antigenicity, virulence, and capacity to resist phagocytosis. The first mutant, designated J-5, produces a cell wall lipopolysaccharide, the side chains of which do not contain galactose, glucose, N-acetylglucosamine, or colitose. The second mutant produces a cell wall lipopolysaccharide which lacks only colitose. The capacity of these various organisms to kill mice was strikingly different. E. coli O111 was 1000 times as virulent as J-5, and 100 times as virulent as L-2. The capacity of the organisms to kill mice was correlated with their ability to resist phagocytosis and to persist in the peritoneal cavity. The parent strain of O111 resisted phagocytosis by macrophages in vivo and polymorphonuclear leukocytes in vitro. The mutants did not, and the organism most deficient in the saccharide component of its LPS was most susceptible to phagocytosis and least virulent. These results were corroborated by growing the mutants in appropriately supplemented media which permitted the synthesis of complete LPS, reversed the susceptibility to phagocytosis, and restored virulence. Finally, serological reactivity was consistent with previous observations which had demonstrated that the O antigenicity of E. coli is determined by the saccharide composition of its cell wall lipopolysaccharide. Despite the difference in the capacity of the various log-phase organisms to kill mice when injected intraperitoneally, purified lipopolysaccharides extracted from them did not differ significantly in their capacity to kill or produce fever. Thus virulence was shown to be independent of endotoxin activity which in turn seemed to be unrelated to the saccharide composition of the cell wall LPS. Collectively, these data provide at least a partial molecular definition of virulence in E. coli by demonstrating that the presence or absence of specific sugars in its cell wall lipopolysaccharide is a determinant of its antiphagocytic capacity and its virulence.

Myeloablative therapy with autologous stem cell rescue for patients with Ewing sarcoma.

The aim of this study was to identify risk factors associated with PFS in patients with Ewing sarcoma undergoing ASCT; 116 patients underwent ASCT in 1989-2000 and reported to the Center for International Blood and Marrow Transplant Research. Eighty patients (69%) received ASCT as first-line therapy and 36 (31%), for recurrent disease. Risk factors affecting ASCT were analyzed with use of the Cox regression method. Metastatic disease at diagnosis, recurrence prior to ASCT and performance score <90 were associated with higher rates of disease recurrence/progression. Five-year probabilities of PFS in patients with localized and metastatic disease at diagnosis who received ASCT as first-line therapy were 49% (95% CI 30-69) and 34% (95% CI 22-47) respectively. The 5-year probability of PFS in patients with localized disease at diagnosis, and received ASCT after recurrence was 14% (95% CI 3-30). PFS rates after ASCT are comparable to published rates in patients with similar disease characteristics treated with conventional chemotherapy, surgery and irradiation suggesting a limited role for ASCT in these patients. Therefore, ASCT if considered should be for high-risk patients in the setting of carefully controlled clinical trials.

Alternative donor bone marrow transplant for children with Philadelphia chromosome ALL.

Children with Philadelphia chromosome positive (Ph+) acute lymphocytic leukemia (ALL) have only a 20% event-free survival when treated with chemotherapy alone. Bone marrow transplant (BMT) for patients with matched siblings has been associated with significantly better long-term survival. We asked whether children who lack a matched sibling donor would do as well if an alternative donor was utilized. Between 1987 and 2002, we transplanted 29 children and adolescents using either an unrelated donor (23) or a mismatched family member (six). The conditioning regimen included cytosine-arabinoside, cyclophosphamide and total body irradiation. Graft-versus-host disease (GVHD) prophylaxis consisted of T-cell depletion (antibody T10B9 or OKT3 and complement) with post transplant cyclosporine (CSA). All patients engrafted. Four developed grades III-IV acute GVHD. Three of 24 evaluable patients developed extensive chronic GVHD. Two patients died of relapse (7%). Two long-term survivors (>6 years) died of malignant glioblastoma multiforme. Event-free survival at 3, 5, and 10 years is 56, 51, and 46%, respectively. Five of six patients in >CR2 or relapse at the time of transplant died. Our data should encourage the use of alternative donor transplants early in the course of disease for children with Ph+ ALL.

Bone marrow transplants from mismatched related and unrelated donors for severe aplastic anemia.

For patients with acquired severe aplastic anemia without a matched sibling donor and not responding to immunosuppressive treatment, bone marrow transplantation from a suitable alternative donor is often attempted. We examined risks of graft failure, graft-versus-host disease and overall survival after 318 alternative donor transplants between 1988 and 1998. Sixty-six patients received allografts from 1-antigen and 20 from >1-antigen mismatched related donors; 181 from matched and 51 from mismatched unrelated donors. Most patients were young, had had multiple red blood cell transfusions and poor performance score at transplantation. We did not observe differences in risks of graft failure and overall mortality by donor type. The probabilities of graft failure at 100 days after 1-antigen mismatched related donor, >1-antigen mismatched related donor, matched unrelated donor and mismatched unrelated donor transplants were 21, 25, 15 and 18%, respectively. Corresponding probabilities of overall survival at 5 years were 49, 30, 39 and 36%, respectively. Although alternative donor transplantation results in long-term survival, mortality rates are high. Poor performance score and older age adversely affect outcomes after transplantation. Therefore, early referral for transplantation should be encouraged for patients who fail immunosuppressive therapy and have a suitable alternative donor.

Efficacy and safety of rasburicase, a recombinant urate oxidase (Elitek), in the management of malignancy-associated hyperuricemia in pediatric and adult patients: final results of a multicenter compassionate use trial.

The recombinant urate oxidase, rasburicase (Elitek, Sanofi-Synthelabo, Inc.), has recently received regulatory approval for the prevention and treatment of hyperuricemia in children with leukemia, lymphoma, and solid tumors. Prior to approval, 682 children and 387 adults in the US and Canada received rasburicase on compassionate-use basis. Uric acid concentration declined rapidly in both adult and pediatric patients after rasburicase treatment. Similar responses were observed in patients treated with subsequent courses. Possible drug-related adverse events, including allergic reactions, were uncommon. These data confirm that rasburicase is effective and safe for the treatment and prophylaxis of children and adults with malignancy-associated hyperuricemia.

Pediatric Oncology Group (POG) studies of acute myeloid leukemia (AML): a review of four consecutive childhood AML trials conducted between 1981 and 2000.

From 1981 to 2000, a total of 1823 children with acute myeloid leukemia (AML) enrolled on four consecutive Pediatric Oncology Group (POG) clinical trials. POG 8101 demonstrated that the induction rate associated with the 3+7+7 combination of daunorubicin, Ara-C, and 6-thioguanine (DAT) was greater than that associated with an induction regimen used to treat acute lymphoblastic leukemia (82 vs 61%; P=0.02). Designed as a pilot study to determine the feasibility of administration of noncross-resistant drug pairs and later modified to assess the effect of dose intensification of Ara-C during the second induction course, POG 8498 confirmed the high initial rate of response to DAT (84.2%) and showed that dose intensification of Ara-C during the second induction course resulted in a trend toward higher event-free survival (EFS) estimates than did standard-dose DAT (2+5) during the second induction course (5 year EFS estimates, 22 vs 27%; P=0.33). Age <2 years and leukocyte count <100 000/mm3 emerged as significantly good prognostic factors. The most significant observation made in the POG 8498 study was the markedly superior outcome of children with Down's syndrome who were treated on the high-dose Ara-C regimen. POG 8821 compared the efficacy of autologous bone marrow transplantation (BMT) with that of intensive consolidation chemotherapy. Intent-to-treat analysis revealed similar 5-year EFS estimates for the group that underwent autologous BMT (36+/-4.7%) and for the group that received only intensive chemotherapy (35+/-4.5%) (P=0.25). There was a high rate of treatment-related mortality in the autologous transplantation group. The study demonstrated superior results of allogeneic BMT for patients with histocompatible related donors (5-year EFS estimate 63+/-5.4%) and of children with Down's syndrome (5-year EFS estimate, 66+/-8.6%). The POG 9421 AML study evaluated high-dose Ara-C as part of the first induction course and the use of the multidrug resistance modulator cyclosporine. Preliminary results showed that patients receiving both high-dose Ara-C for remission induction and the MDR modulator for consolidation had a superior outcome (5-year EFS estimate, 42+/-8.2%) than did patients receiving other treatment; however, the difference was not statistically significant. These four studies demonstrate the importance of dose intensification of Ara-C in the treatment of childhood AML; cytogenetics as the single most prognostic factor and the unique curability of AML in children with Down's syndrome.

High concordance from independent studies by the Children's Cancer Group (CCG) and Pediatric Oncology Group (POG) associating favorable prognosis with combined trisomies 4, 10, and 17 in children with NCI Standard-Risk B-precursor Acute Lymphoblastic Leukemia: a Children's Oncology Group (COG) initiative.

Chromosome aberrations have a major role in pediatric acute lymphoblastic leukemia (ALL) risk assignment. The Children's Cancer Group (CCG) and the Pediatric Oncology Group (POG) independently assessed the significance of trisomy for chromosomes 4, 10, and 17 in National Cancer Institute (NCI) Standard- and High-Risk ALL. Data from 1582 (CCG) and 3902 (POG) patients were analyzed. Eight-year event-free survivals (EFS) of 91% (CCG) and 89% (POG) (P < 0.001) were achieved in patients assigned to NCI Standard Risk whose leukemic cells had simultaneous trisomies 4, 10, and 17. Both groups showed the degree of favorable prognostic importance increased with the actual number of favorable trisomies. POG analyses also demonstrated hyperdiploidy (> or =53 chromosomes) was less of an independently significant prognostic factor in the absence of these key trisomies. This finding supported conclusions from previous CCG and POG studies that specific trisomies are more important than chromosome number in predicting outcome in pediatric B-precursor ALL. In NCI Higher Risk patients, the number of favorable trisomies was not prognostically significant, but showed the same trend. Moreover, specific trisomies 4, 10, and 17 remain associated with favorable prognosis in Standard-Risk B-precursor ALL, even in the context of very different treatment approaches between the groups.

Accumulation of methotrexate and methotrexate polyglutamates in lymphoblasts and treatment outcome in children with B-progenitor-cell acute lymphoblastic leukemia: a Pediatric Oncology Group study.

We reported that children with B-progenitor-cell acute lymphoblastic leukemia (BpALL) treated in the early 1980s whose lymphoblasts accumulated high levels of methotrexate (MTX) and of methotrexate polyglutamates (MTXPGs) in vitro had an improved 5-year event-free survival (EFS) (65% (standard error (s.e.) 12%) vs 22% (s.e. 9%)). We repeated this study in children with BpALL treated in the early 1990s. The major change in treatment was the addition of 12 24-h infusions of 1 g/M2 MTX with leucovorin rescue (IDMTX). In 87 children treated on Pediatric Oncology Group (POG) study 9005 and POG 9006, the 5-year EFS for those whose lymphoblasts accumulated high levels of MTX and MTXPGs (79.2%, s.e. 8.3%) was not significantly different from that of patients with lesser accumulation of MTX and MTXPGs (77.7%, s.e. 5.4%). These findings support the notion that higher dose MTX therapy has contributed to increased cure, particularly for patients whose lymphoblasts accumulate the drug less well.

Increased whole-body protein turnover in sick children with newly diagnosed leukemia or lymphoma.

Using a single dose, [15N]glycine turnover technique, whole body rates of proteins synthesis and breakdown were assessed in six healthy children and in eight children with newly diagnosed leukemia (DeWys, W. D. Cancer Res., 42: 721s-726s, 1982) or lymphoma (Baracos, V., Rodemann, H. P., Dinarello, C. A., and Goldberg, A. L. N. Engl. J. Med., 308: 553-558, 1983). Based on excretion of 15N as urinary ammonia, synthesis (g protein per kg body weight per day) was significantly (p less than 0.025) higher in the cancer patients [5.4 +/- 1.5 (S.D.)] compared to the controls (3.6 +/- 0.9); breakdown was also higher (p less than 0.02) in the patients (5.5 +/- 1.8) compared to the controls (3.1 +/- 1.1). When only the seven patients with leukemia were considered, there also were significant increases in synthesis (5.4 +/- 1.6, p less than 0.05) and breakdown (5.4 +/- 1.9, p less than 0.025) compared to controls. Increases in both synthesis and breakdown were also observed in the patients when the protein turnover data were expressed as a function of the rate of creatinine excretion or the calculated lean body mass. We conclude that whole body protein turnover is increased in sick children at the time of diagnosis with some forms of newly diagnosed cancer.

Thioredoxin expression in primary T-cell acute lymphoblastic leukemia and its therapeutic implication.

Increased expression of intracellular thioredoxin has been implicated in the inhibition of apoptosis and in a decrease in the sensitivity of the malignancies to drug-induced apoptosis. In the present studies, we analyzed expression of thioredoxin in samples from 28 children with T-cell acute lymphoblastic leukemia and analyzed their sensitivity toward inhibition of thioredoxin expression. Thioredoxin was expressed in variable amounts. Higher expression was associated with higher WBC counts. Exogenously added thioredoxin stimulated proliferation of clonogenic cells among the T-cell acute lymphoblastic leukemia samples expressing relatively lower levels of intracellular thioredoxin, whereas there was no effect on the clonogenic cells expressing high levels of thioredoxin. In addition, there was differential sensitivity of the leukemia clonogenic cells toward 1-methylpropyl 2-imidazolyl disulfide, an inhibitor of thioredoxin expression, as compared with normal hematopoietic progenitors. This suggests the possibility of using this approach for treatment. Because overexpression of thioredoxin is associated with resistance to many anticancer drugs, the inhibition of thioredoxin expression may overcome this drug resistance and probably sensitize leukemia cells to other chemotherapeutic agents.

Therapy of refractory or recurrent childhood acute myeloid leukemia using amsacrine and etoposide with or without azacitidine: a Pediatric Oncology Group randomized phase II study.

PURPOSE: A randomized study compared the combination of amsacrine (100 mg/m2/d on days 1 to 5) and etoposide (200 mg/m2/d on days 1 to 3) with the same two agents plus azacitidine (250 mg/m2/d on days 4 to 50) for the therapy of induction-resistant or relapse childhood acute myeloid leukemia (AML). PATIENTS AND METHODS: One hundred sixty-seven assessable children with AML who either had failed to respond to primary induction therapy (group 1, n = 41) or had relapsed (group 2, n = 126) were randomized. RESULTS: Overall, there were 56 complete responses (34%; SE 4%). Among primary refractory patients (group 1), the complete response rate was higher with the three-drug regimen (18% vs 53%, P = .03). In the relapsed patients (group 2), there was no difference in complete response rates related to treatment (31% vs 35%, P = .3). There were 17 early deaths. The major toxicities for both regimens were myelosuppression and infection. CONCLUSION: The overall complete response rate of 34% in this patient population is indicative of effective antileukemic activity. For patients with relapsed leukemia, the addition of azacitidine to etoposide and amsacrine did not improve response. The suggested advantage of the three-drug regimen for induction failures warrants further investigation.

Intensification with intermediate-dose intravenous methotrexate is effective therapy for children with lower-risk B-precursor acute lymphoblastic leukemia: A Pediatric Oncology Group study.

PURPOSE: To determine whether early intensification with 12 courses of intravenous (IV) methotrexate (MTX) and IV mercaptopurine (MP) is superior to 12 courses of IV MTX alone for prevention of relapse in children with lower-risk B-lineage acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: Six hundred fifty-one eligible patients were entered onto the study. Vincristine, prednisone, and asparaginase were used for remission induction therapy. Patients were randomized to receive intensification with IV MTX 1,000 mg/m(2) plus IV MP 1,000 mg/m(2) (regimen A) or IV MTX 1,000 mg/m(2) alone (regimen C). Twelve courses were administered at 2-week intervals. Triple intrathecal therapy was used for CNS prophylaxis. Continuation therapy included standard oral MP, weekly MTX, and triple intrathecal therapy every 12 weeks for 2 years. RESULTS: Six hundred forty-five patients (99.1%) achieved remission. Three hundred twenty-five were assigned to regimen A and 320 to regimen C. The estimated 4-year overall continuous complete remission for patients treated with regimen A is 82.1% (SE = 2.4%) and for regimen C is 82.2% (SE = 2.6%; P =.5). No significant difference in overall outcome was shown by sex or race. Serious grade 3/4 neurotoxicity, principally characterized by seizures, was observed in 7.6% of patients treated with either regimen. CONCLUSION: Intensification with 12 courses of IV MTX is an effective therapy for prevention of relapse in children with B-precursor ALL who are at lower risk for relapse but may be associated with an increased risk for neurotoxicity. Prolonged infusions of MP combined with IV MTX did not provide apparent advantage.

Intermediate-dose intravenous methotrexate with intravenous mercaptopurine is superior to repetitive low-dose oral methotrexate with intravenous mercaptopurine for children with lower-risk B-lineage acute lymphoblastic leukemia: a Pediatric Oncology Group phase III trial.

PURPOSE: To determine whether early intensification with 12 courses of intravenous methotrexate and intravenous mercaptopurine (IVMTX/IVMP) is superior to 12 courses of repetitive, low-dose oral MTX with I.V. MP (LDMTX/IVMP) for prevention of relapse in children with lower-risk B-lineage acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: Seven hundred nine patients were entered onto the study. Vincristine, prednisone, and asparaginase were used for remission induction. Patients were randomized to receive intensification with either IVMTX 1,000 mg/m2 plus IVMP 1,000 mg/m2 (regimen A) or LDMTX 30 mg/m2 every 6 hours for six doses with IVMP 1,000 mg/m2 (regimen B). Twelve courses were administered at 2-week intervals. Triple intrathecal therapy (TIT) was used for CNS prophylaxis. Continuation therapy included standard oral MP, weekly MTX, and TIT every 12 weeks for 2 years. RESULTS: Six hundred ninety-nine (99%) patients achieved remission. Three hundred forty-nine were assigned to regimen A and 350 to regimen B. The estimated 4-year continuous complete remission (CCR) rate for patients treated with regimen A is 80.3% (SE = 2.9%) and with regimen B is 75.9% (SE = 3.1%). By log-rank analysis, regimen A demonstrated superior CCR (P = .013). Transient neutropenia/thrombocytopenia, bacterial sepsis, neurotoxicity, stomatitis, and hospitalizations were more frequent among patients treated on regimen A. CONCLUSION: Intensification with IVMTX/IVMP is more effective than LDMTX/IVMP for prevention of relapse in children with B-precursor ALL at lower risk for relapse.

Recombinant urate oxidase for the prophylaxis or treatment of hyperuricemia in patients With leukemia or lymphoma.

PURPOSE: To improve the control of hyperuricemia in patients with leukemia or lymphoma, we tested a newly developed uricolytic agent, recombinant urate oxidase (SR29142; Rasburicase; Sanofi-Synthelabo, Inc, Paris, France), which catalyzes the oxidation of uric acid to allantoin, a highly water-soluble metabolite readily excreted by the kidneys. PATIENTS AND METHODS: We administered Rasburicase intravenously, at 0.15 or 0.20 mg/kg, for 5 to 7 consecutive days to 131 children, adolescents, and young adults with newly diagnosed leukemia or lymphoma, who either presented with abnormally high plasma uric acid concentrations or had large tumor cell burdens. Blood levels of uric acid, creatinine, phosphorus, and potassium were measured daily. The pharmacokinetics of Rasburicase, the urinary excretion rate of allantoin, and antibodies to Rasburicase were also studied. RESULTS: At either dosage, the recombinant enzyme produced a rapid and sharp decrease in plasma uric acid concentrations in all patients. The median level decreased by 4 hours after treatment, from 9.7 to 1 mg/dL (P =.0001), in the 65 patients who presented with hyperuricemia, and from 4.3 to 0.5 mg/dL (P =.0001) in the remaining 66 patients. Despite cytoreductive chemotherapy, plasma uric acid concentrations remained low throughout the treatment (daily median level, 0.5 mg/dL). The urinary excretion rate of allantoin increased during Rasburicase treatment, peaking on day 3. Serum phosphorus concentrations did not change significantly during the first 3 days of treatment, decreased significantly by day 4 in patients presenting with hyperuricemia (P =.0003), and fell within the normal range in all patients by 48 hours after treatment. Serum creatinine levels decreased significantly after 1 day of treatment in patients with or without hyperuricemia at diagnosis (P =.0003 and P =.02, respectively) and returned to normal range in all patients by day 6 of treatment. Toxicity was negligible, and none of the patients required dialysis. The mean plasma half-lives of the agent were 16.0 +/- 6.3 (SD) hours and 21.1 +/- 12.0 hours, respectively, in patients treated at dosages of 0.15 or 0.20 mg/kg. Seventeen of the 121 assessable patients developed antibodies to the enzyme. CONCLUSION: Rasburicase is safe and highly effective for the prophylaxis or treatment of hyperuricemia in patients with leukemia or lymphoma.

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.

Partially matched bone marrow transplantation in patients with myelodysplastic syndromes.

Six patients with a myelodysplastic syndrome (MDS) were treated with bone marrow transplantation (BMT) using partially-matched related (3) or unrelated (3) donors. Patients' ages ranged from 7 to 31 years (median, 10 years). Bone marrow karyotype abnormalities were present in five patients included four with monosomy 7 and one with trisomy 8. One patient was in complete remission before transplant; the remaining five had excess of blasts or were undergoing leukemic transformation. Donor, and recipient were mismatched at the DR locus (2), A locus (2), B locus (1), or A and B loci (1). Conditioning included busulfan, cytarabine, cyclophosphamide, methylprednisolone, and total body irradiation. Cyclosporine was started on day -1. Marrows were T-cell depleted using a monoclonal antibody (MoAb) (CD3) and normal rabbit serum. Four patients engrafted routinely. One patient died of aspergillosis before engraftment (day 12) and one patient failed to engraft on first attempt, but engrafted following additional preparation. Median time to neutrophils greater than 500/microL and platelets greater than 25,000/microL were 16 and 19 days, respectively. Acute graft-v-host disease (GVHD) was less than or equal to grade II in all patients. One patient died with recurrent disease (day 257). One patient died at day 515 of pancreatitis and respiratory failure. Three patients are alive and disease-free at 240, 395, and 560 days post-BMT including two patients with unrelated donors. Partially matched T-depleted bone marrow from related or unrelated donors may be effective, and possibly curative therapy for patients with MDS who lack a histocompatibility locus antigen (HLA)-identical sibling donor.

Prognostic factors in childhood acute myelogenous leukemia.

The prognostic significance of initial clinical and laboratory parameters was evaluated in 125 children with acute myelogenous leukemia (AML) treated on two consecutive protocols (VAPA and 80-035). Both protocols used an anthracycline with cytosine arabinoside (ara-C) for induction therapy followed by 12 to 14 months of intensive sequential postremission chemotherapy. Results are similar for the two treatment regimens. Seventy-two percent of patients achieved a complete remission, with 42% projected 5-year disease-free survival for the complete responders. Monocytic or myelomonocytic leukemic subtype (French-American-British [FAB] types M4 and M5), WBC count less than 100,000/microL, and age less than 2 years at diagnosis all predicted increased risk of relapse and decreased overall survival in univariate analyses. FAB subtype and high white count continued to predict for an increased risk of relapse in multivariate analyses and only M5 leukemic subtype independently predicted for poor survival. Patients with M4 or M5 leukemic subtype had a higher incidence of initial relapses in the CNS. The addition of intrathecal cytosine arabinoside in the second protocol, 80-035, decreased the percentage of patients with initial failure in the CNS, but did not improve overall survival. Improved CNS prophylaxis, better systemic therapy, and/or different treatment strategies are needed to improve therapy in these high-risk patients.

Acute neurotoxicity in children with B-precursor acute lymphoid leukemia: an association with intermediate-dose intravenous methotrexate and intrathecal triple therapy--a Pediatric Oncology Group study.

PURPOSE: To describe the incidence of acute neurotoxicity (NT) in children with lower risk B-precursor acute lymphoid leukemia (ALL) treated with intermediate-dose methotrexate (MTX) or divided dose oral MTX with or without intravenous (i.v.) mercaptopurine (MP) and extended intrathecal triple therapy. PATIENTS AND METHODS: Thirteen hundred four patients were entered onto Pediatric Oncology Group (POG) 9005, a randomized phase III trial, between January 11, 1991 and September 1, 1994. After remission induction, patients were randomized to one of three 24-week intensification schedules: regimen A, MTX 1,000 mg/m2 i.v. infused over 24 hours and MP 1,000 mg/m2 i.v. infused over 6 hours; regimen B, low-dose repetitive MTX 30 mg/m2 orally every 6 hours for six doses and i.v. MP; or regimen C, i.v. MTX alone. Intensification was given every 2 weeks for 12 courses. CNS prophylaxis was age-adjusted intrathecal MTX (ITM). In August 1992, the CNS prophylaxis was changed to age-adjusted triple intrathecal therapy (TIT). Reports of grades 3 and 4 acute NT were reviewed. RESULTS: Acute NT was reported in 95 of 1,218 (7.8%) eligible patients treated on POG 9005. The incidence by regimen was regimen A, 46 of 543 patients (8.3%); regimen B, 13 of 354 patients (3.7%); and regimen C, 36 of 321 patients (11.2%) (P < .001). The majority of events were seizures and the median number of days to first occurrence of symptomatic NT after ITM or TIT was 10 to 11 days. Computed tomography (CT) or magnetic resonance imaging (MRI) evidence consistent with leukoencephalopathy (LE), with or without the presence of cerebral calcifications, was observed in 75% and 77.1 % of symptomatic patients treated on regimens A and C, respectively, but in only 15.4% of symptomatic patients treated on regimen B (P < .001). Factors associated with an increased incidence of NT included increased cumulative exposure with repeated i.v. MTX (regimens A and C v B), increased MTX-leucovorin (LCV) ratio (regimens A and C v B), and choice and timing of TIT therapy. The use of i.v. MP during intensification did not appear to contribute to these complications. The switch to TIT CNS prophylaxis was associated with an inferior overall 4-year continuous complete remission (CCR) (P=.031) when compared with ITM. CONCLUSION: Intensification with repeated i.v. MTX in the setting of low-dose LCV rescue was associated with a higher risk for acute NT and LE, especially in patients who received concomitant TIT. The long-term consequences for affected patients remain unknown.

High-dose melphalan and cyclophosphamide with autologous bone marrow rescue for recurrent/progressive malignant brain tumors in children: a pilot pediatric oncology group study.

PURPOSE: To determine the maximum-tolerated dose of cyclophosphamide (CTX) when administered sequentially with melphalan 60 mg/m2/d for 3 days, followed by autologous bone marrow rescue (ABMR), in children with recurrent or progressive malignant brain tumors, and to make preliminary observations on efficacy. PATIENTS AND METHODS: Nineteen patients between the ages of 2 and 21 years were enrolled and 18 were assessable for effects of therapy. CTX was administered to seven patients at 750 mg/m2/d for 4 days, to five patients at 975 mg/m2/d, to three patients at 1,200 mg/m2/d, and to three patients at 1,500 mg/m2/d. All patients received ABMR. Granulocyte-macrophage colony-stimulating factor (GM-CSF) was used in 15 patients. Toxicity, response to therapy, time to progression, and survival and monitored. RESULTS: The median time to a granulocyte count more than 500/dL was 19 days (range, 11 to 39), and for a platelet count more than 50,000/dL was 33 days (range, 16 to 60). Four heavily pretreated patients (22%) died of transplant-related complications. No dose-limiting, non-hematologic toxicities were defined for the study. Seven of 18 patients (39%) had a complete response (CR) or a partial response (PR). These included four patients with medulloblastoma (CR and three PRs), two with germinomas (two CRs), and one with ependymoma (one CR). The estimated 1-year survival rate was 39% (SE 12%). CONCLUSION: CTX, at a maximum total dose of 6,000 mg/m2, administered sequentially with melphalan and followed by ABMR was tolerable in children with recurrent brain tumors who had not been heavily pretreated. Responses were seen in patients with medulloblastoma and germinomas. Further trials in children with chemosensitive tumors, with minimal residual disease, are planned.

Intermediate-dose intravenous methotrexate and mercaptopurine therapy for non-T, non-B acute lymphocytic leukemia of childhood: a Pediatric Oncology Group study.

Methotrexate (MTX) and mercaptopurine (MP) are the mainstays of continuation therapy for acute lymphocytic leukemia (ALL). These drugs are stored in tissues as active metabolites. Relapse in ALL might reflect failure to achieve adequate intracellular drug levels. Assured (parenteral) delivery of higher doses of MTX and MP should maximize tissue levels of these drugs by overcoming individual variations in absorption, metabolism, clearance, and compliance. Fifty-nine children with ALL at lower risk of relapse received 12 intensive MTX/MP courses immediately after 4 weeks of standard vincristine, prednisone, and asparaginase induction. Each 2-week intensive course included: MTX, 200 mg/m2 intravenous (IV) push then 800 mg/m2 IV over 24 hours on day 1; MP, 200 mg/m2 IV push then 800 mg/m2 IV over 8 hours on day 2; MTX, 20 mg/m2 intramuscularly on day 8; and MP, 50 mg/m2 orally daily on days 8 to 14. After the 6 months of intensive therapy, continuation therapy was weekly MTX/MP (as on days 8 to 14) for 1 or 2 years. Age-based MTX was given intrathecally (IT) for CNS prophylaxis. All patients entered remission. Three patients relapsed: bone marrow (at 24 and 37 months), and bone marrow and CNS (at 34 months). There were no isolated CNS relapses or deaths in remission. Event-free survival at 4 years is 94% (SE, 7%) by Kaplan-Meier analysis. Toxicities (infection, mucositis) occurred in less than 10% of intensive MTX/MP courses. However, a child with Down's syndrome withdrew after three courses because of recurrent severe mucositis. Further studies of this regimen are in progress.