Correlation between high vascular endothelial growth factor-A serum levels and treatment outcome in patients with standard-risk acute lymphoblastic leukemia: a report from Children's Oncology Group Study CCG-1962.

PURPOSE: Many molecular pathways, including cell cycle control, angiogenesis, and drug resistance, mediate tumor growth and survival. Vascular endothelial growth factor-A (VEGF-A) serum levels <40 and >100 pg/mL have been associated with good and poor prognoses, respectively. EXPERIMENTAL DESIGN: The hypothesis was that serum VEGF-A levels in standard-risk acute lymphoblastic leukemia pediatric patients at induction are predictive of event-free survival (EFS). One hundred seventeen patients were entered in CCG-1962 study and randomized into the native and polyethylene glycolated asparaginase arms. VEGF-A levels were quantified by an ELISA assay. RESULTS: All patients had a decrease in VEGF-A levels by day 14 of induction, but they later dichotomized; EFS group levels remained low and event group levels increased. A correlation exists between high VEGF-A levels at entry to induction and time to event. Moreover, 6-year EFS patients have lower end of induction VEGF-A levels (28 +/- 6 pg/mL) than event patients (>100 pg/mL; P < 0.01). Kaplan-Meier curves using various VEGF-A values were produced; with < or =30 at entry into induction (day 0) and < or =60 pg/mL at the end of induction (day 28), patients with low VEGF-A levels had superior EFS (P < 1e-4). Furthermore, patients who had an increase in VEGF-A during induction (DeltaVEGF-positive, days 0-28) were more likely to have an event (P < 1e-4). Bifurcation by asparaginase treatment arm did not alter these results. CONCLUSIONS: These observations strongly support that high VEGF-A levels in induction are an asparaginase treatment-independent predictive marker for EFS. Hence, an anti-VEGF-A therapy should be tested in acute lymphoblastic leukemia.

Phase II trial of oral aminopterin for adults and children with refractory acute leukemia.

PURPOSE: To determine the antileukemic activity of weekly oral aminopterin in patients with refractory acute leukemia; to describe the pharmacodynamic properties of aminopterin; and to contrast the intracellular metabolism of aminopterin and methotrexate by patients' blasts in vitro. EXPERIMENTAL DESIGN: Forty-six patients were enrolled in three strata: children with acute lymphoblastic leukemia (ALL), adults with ALL, and patients with acute myeloid leukemia (AML). Aminopterin was given weekly, in two doses of 2 mg/m(2), 12 hours apart. Limited sampling pharmacokinetic analysis was done during the first week of therapy. Accumulation of [(3)H]aminopterin and [(3)H]methotrexate by leukemic blasts was studied in vitro. RESULTS: Six of 22 children with ALL (27%; 95% confidence interval, 8-47%) had clinically significant responses. None of those with AML and only two of 11 adults with ALL had responses meeting protocol definitions, although peripheral blast counts tended to decrease with therapy in all groups. Mucosal toxicity was minimal, even with limited use of leucovorin rescue. Complete bioavailability of aminopterin was confirmed, with a mean area under the curve of 0.52 +/- 0.03 micromol hour/L after oral dosing. No relationship between aminopterin pharmacokinetics and response was seen. In vitro, aminopterin showed more consistent metabolism by leukemic blasts to polyglutamates than methotrexate. Lineage-specific differences in the pattern of intracellular antifolylpolyglutamates were observed. CONCLUSIONS: Weekly oral aminopterin has significant activity among children with refractory ALL. With greater cellular accumulation and metabolism, more reliable bioavailability than methotrexate, and tolerable toxicity at this dose and schedule, aminopterin deserves further study as a potent alternative to methotrexate.

Phase I trial and pharmacokinetics of gemcitabine in children with advanced solid tumors.

PURPOSE: To determine the maximum tolerated dose, toxicity, and pharmacokinetics of gemcitabine in children with refractory solid tumors. PATIENTS AND METHODS: Gemcitabine was given as a 30-minute infusion for 2 or 3 consecutive weeks every 4 weeks, to 42 patients aged 1 to 21 years. Doses of 1000, 1200 and 1500 mg/m(2) were administered for 3 weeks. Subsequently, gemcitabine was given for only 2 consecutive weeks at 1500, 1800, and 2100 mg/m(2). Plasma concentrations of gemcitabine and its metabolite, 2'2'-difluorodeoxyuridine, were measured in 28 patients. RESULTS: Forty patients who received 132 courses of gemcitabine were assessable for toxicity. The maximum tolerated dose of gemcitabine given weekly for 3 weeks was 1200 mg/m(2). Dose-limiting toxicity was not seen in one-third of children treated at any doses given for 2 weeks. The major toxicity was myelosuppression in three of five patients at 1500 mg/m(2) for 3 weeks, and one of seven patients at 1800 mg/m(2) for 2 weeks. Other serious adverse events were somnolence, fever and hypotension, and rash in three patients. Gemcitabine plasma concentration-time data were fit to a one- (n = 5) or two-compartment (n = 23) open model. Mean gemcitabine clearance and half-life values were 2140 mL/min/m(2) and 13.7 minutes, respectively. One patient with pancreatic cancer had a partial response. Seven patients had stable disease for 2 to 17 months. CONCLUSION: Gemcitabine given by 30-minute infusion for 2 or 3 consecutive weeks every 4 weeks was tolerated well by children at doses of 2100 mg/m(2) and 1200 mg/m(2), respectively.

Asparaginase pharmacokinetics after intensive polyethylene glycol-conjugated L-asparaginase therapy for children with relapsed acute lymphoblastic leukemia.

PURPOSE: Asparaginase therapy is an important component in the treatment of children with acute lymphoblastic leukemia. Polyethylene glycol-conjugated asparaginase (PEG-ASNase) has significant pharmacological advantages over native Escherichia coli asparaginase. We investigated the pharmacokinetics of PEG-ASNase, presence of antibodies to PEG-ASNase, and concentrations of asparagine in serum and cerebrospinal fluid (CSF) in combination chemotherapy for relapsed pediatric acute lymphoblastic leukemia. EXPERIMENTAL DESIGN: Twenty-eight pediatric patients with relapsed medullary (n = 16) and extramedullary (n = 11) acute lymphoblastic leukemia were enrolled at three pediatric institutions and had at least two serum and CSF samples obtained for analysis. Patients received induction therapy (including PEG-ASNase 2500 IU/m2 intramuscularly weekly on days 2, 9, 16, and 23) and intensification therapy (including PEG-ASNase 2500 IU/m2 intramuscularly once on day 7). Serum samples were obtained weekly during induction and intensification. CSF samples were obtained during therapeutic lumbar punctures during induction and intensification. RESULTS: Weekly PEG-ASNase therapy resulted in PEG-ASNase activity of >0.1 IU/ml in 91-100% of patients throughout induction. During intensification, PEG-ASNase on day 7 resulted in PEG-ASNase activity >0.1 IU/ml in 94% and 80% of patients on days 14 and 21, respectively. Serum and CSF asparagine depletion was observed and maintained during induction and intensification in the majority of samples. PEG-ASNase antibody was observed in only 3 patients. CONCLUSIONS: Intensive PEG-ASNase therapy in the treatment of relapsed acute lymphoblastic leukemia reliably results in high-level serum PEG-ASNase activity, and asparagine depletion in serum and CSF is usually achieved. Incorporation of intensive PEG-ASNase in future trials for recurrent acute lymphoblastic leukemia is warranted.

Substitution of oral and intravenous thioguanine for mercaptopurine in a treatment regimen for children with standard risk acute lymphoblastic leukemia: a collaborative Children's Oncology Group/National Cancer Institute pilot trial (CCG-1942).

BACKGROUND: Although mercaptopurine (MP) is conventionally used to treat childhood acute lymphoblastic leukemia (ALL), thioguanine (TG) is a more potent thiopurine in vitro and, when administered orally to patients, achieves cytotoxic drug concentrations in the cerebrospinal fluid (CSF). We performed a pilot study incorporating oral and 24-hr continuous IV infusion (CIVI) TG in children with newly diagnosed standard-risk ALL. PROCEDURE: Children with newly diagnosed standard-risk ALL (age 1-10 years, WBC<50 k) were eligible. Multi-agent chemotherapy was patterned after the Children's Cancer Group (CCG) 105 trial, with the addition of CIVI-TG (480 mg/m2) during consolidation, interim maintenance and maintenance, and substitution of oral TG (60 mg/m2/day) for oral MP during maintenance. RESULTS: Fifty-eight patients (31 female), median age 4.3 years, were enrolled. At 8 years, the relapse-free and overall survival probabilities were 83% and 88%. There were no CNS relapses. Six patients (five males) experienced reversible veno-occlusive disease (VOD) while receiving oral TG, and the study was amended to discontinue TG, changing all patients to oral MP. Red cell TG nucleotide concentrations during oral TG averaged 95 ng (570 pmol)/8x10(8) RBC, greater than concentrations reported with oral MP. CONCLUSION: Although the absence of CNS relapses in this pilot study suggests that TG may contribute to the prevention of CNS recurrences, the development of VOD negatively impacts the risk:benefit ratio of substituting TG for MP.

Toxicity and efficacy of intensive chemotherapy for children with acute lymphoblastic leukemia (ALL) after first bone marrow or extramedullary relapse.

BACKGROUND: Approximately 25% of children newly diagnosed with acute lymphoblastic leukemia (ALL) will eventually experience leukemic relapse, with bone marrow being the most common site of recurrence. The ability to achieve a durable second remission is complicated by toxicity and resistant disease. We report a novel combination of chemotherapy for relapsed pediatric ALL. PROCEDURE: Thirty pediatric patients with relapsed medullary (n = 18) and extra-medullary (n = 12) ALL were enrolled at three pediatric institutions. Following receipt of induction and the first Block A and Block B of intensification, each patient was evaluated for toxicity, efficacy in achieving remission, and long-term survival. Additionally, minimal residual disease (MRD) detection by multidimensional flow cytometry (MDF) was performed. RESULTS: During induction, the major non-hematopoeitic toxicities were mucositis (30% of patients) and bacteremia (50% of patients). Two patients (7%) died of toxicity during induction. Toxicity during intensification Block 1A and 1B was markedly reduced. Eight-nine percent of patients with marrow disease achieved a remission following induction and intensification. The event-free survival (EFS) for all patients at 2 and 4 years were 60% (95% CI: 42-78%) and 49% (95% CI: 30-68%), respectively. CONCLUSIONS: This regimen for patients with relapsed ALL was successful in achieving a second remission for the majority of patients with acceptable toxicity.

A pharmacoeconomic analysis of pegaspargase versus native Escherichia coli L-asparaginase for the treatment of children with standard-risk, acute lymphoblastic leukemia: the Children's Cancer Group study (CCG-1962).

PURPOSE: The purpose of this pharmacoeconomic analysis was to compare pegaspargase. a newer chemotherapeutic agent used for treating acute lymphoblastic leukemia, with native Escherichia coli L-asparaginase in induction, delayed intensification 1 and delayed intensification 2. MATERIALS AND METHODS: A subset of patients with newly diagnosed, standard-risk, acute lymphoblastic leukemia enrolled in the Children's Cancer Group (CCG) study CCG-1962 at seven participating institutions gave consent and was enrolled in our pharmacoeconomic analysis study. Societal (transportation, lodging, missed workdays, food, babysitter) and payer (frequency of encounters) cost data were collected from diaries (n = 27). Additional payer costs, such as drug costs, cost per clinic visit, and cost per inpatient day stay were collected from patients in CCG-1962 and participating institutions. We considered costs of therapy, including higher pegaspargase costs when comparing regimens of pegaspargase versus native E. coli L-asparaginase in induction, delayed intensification 1, and delayed intensification 2. RESULTS: Our results showed that the costs of the two therapies were similar from the payer perspective, with pegaspargase costing 1.8% more than E. coli L-asparaginase. The difference between groups also was small (<1%) from the societal perspective. Inpatient stay accounted for 88% of pegaspargase payer costs and 91% of the native E. coli L-asparaginase costs. CONCLUSION: We recommend that pegaspargase not be withheld from treatment protocols solely because of its higher pharmacy costs.

A randomized comparison of native Escherichia coli asparaginase and polyethylene glycol conjugated asparaginase for treatment of children with newly diagnosed standard-risk acute lymphoblastic leukemia: a Children's Cancer Group study.

For this study, 118 children with standard-risk acute lymphoblastic leukemia (ALL) were given randomized assignments to receive native or pegylated Escherichia coli asparaginase as part of induction and 2 delayed intensification phases. Patients treated with pegaspargase had more rapid clearance of lymphoblasts from day 7 and day 14 bone marrow aspirates and more prolonged asparaginase activity than those treated with native asparaginase. In the first delayed intensification phase, 26% of native asparaginase patients had high-titer antibodies, whereas 2% of pegaspargase patients had those levels. High-titer antibodies were associated with low asparaginase activity in the native arm, but not in the pegaspargase arm. Adverse events, infections, and hospitalization were similar between arms. Event-free survival at 3 years was 82%. A population pharmacodynamic model using the nonlinear mixed effects model (NONMEM) program was developed that closely fit the measured enzyme activity and asparagine concentrations. Half-lives of asparaginase were 5.5 days and 26 hours for pegaspargase and native asparaginase, respectively. There was correlation between asparaginase enzymatic activity and depletion of asparagine or glutamine in serum. In cerebrospinal fluid asparagine, depletion was similar with both enzyme preparations. Intensive pegaspargase for newly diagnosed ALL should be tested further in a larger population.