Therapeutic effects and pharmacokinetics of recombinant human granulocyte-macrophage colony-stimulating factor in childhood cancer patients receiving myelosuppressive chemotherapy

Twenty-five children with refractory solid tumors were given recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) in escalated doses of 60 to 1,500 micrograms/m2 as 2-hour intravenous infusions, beginning 24 hours after myelosuppressive treatment with cisplatin and etoposide. Tolerance to rhGM-CSF was exceptional even at dose levels that exceeded the maximum-tolerated dosage (MTD) reported for adults. The agent produced dose-related increases in platelet and neutrophil counts, resulting in significantly shorter durations of severe neutropenia and thrombocytopenia (P less than .01 for each analysis). At the higher dosages (greater than or equal to 750 micrograms/m2), treatment with rhGM-CSF reduced the median number of days of antibiotic therapy for fever and neutropenia by approximately one half. We conclude that rhGM-CSF is well tolerated by leukopenic children in doses as high as 1,500 micrograms/m2. An MTD was not reached in this study. The ability of the growth factor to reduce severe neutropenia and thrombocytopenia suggests it will have an important role in the management of childhood solid tumors.     

Vincristine pharmacokinetics after repetitive dosing in children

Purpose: We studied vincristine disposition after 169 weekly i.v. bolus injections in 32 children with acute lymphoblastic leukemia, non-Hodgkin lymphoma, or Wilms' tumor. The aim of the study was to determine intrapatient and interpatient variability in vincristine disposition and demographic, clinical, and biochemical characteristics influencing this variability. Methods: Vincristine plasma concentrations were measured by a high-performance liquid chromatography assay with electrochemical detection. A limited sampling strategy was used based on a bayesian parameter estimation algorithm that is part of the ADAPT II software package. A two-compartment, first-order model was fitted to the data, and pharmacokinetic parameters were calculated from the model using the ADAPT II software. For statistical analysis, analysis of variance (ANOVA), t test, simple and multiple regression analysis, and non-parametric or robust equivalents were used. Results: Results showed a large intrapatient and interpatient variability in distribution half-life, elimination half-life, total body clearance, apparent volume of distribution at steady state, and area under the concentration–time curve. Intrapatient variability was significantly smaller than interpatient variability for all these parameters except distribution half-life. The diagnosis or treatment protocol turned out to be the most predictive characteristic; leukemia and non-Hodgkin lymphoma patients had a significantly higher total body clearance than Wilms' tumor patients. Conclusions: We conclude that both intrapatient and interpatient variability in vincristine pharmacokinetics is large in pediatric cancer patients and that variability, although significantly influenced by diagnosis, largely remains unpredictable. Received: 11 September 1998 / Accepted: 5 February 1999     

Cognition before and after chemotherapy alone in children with chiasmatic-hypothalamic tumors

Studies on adults with cancer, with or without CNS involvement, have shown that chemotherapy (CT) can affect cognitive functions. Two studies on children with optic pathway gliomas, involving the hypothalamus in some cases, and treated with CT according to various protocols reported the children maintaining a good IQ (no other cognitive abilities were tested). Among 18 children with chiasmatic-hypothalamic tumors (CHT) given front-line CT treatment at our institute using the same protocol (cisplatin and etoposide), we screened eight children for cognitive sequelae, correlating their test performance with several clinical variables (age at diagnosis and at time of treatment, time elapsing since treatment, and tumor volume reduction). The neuropsychological evaluation involved measuring IQ in all eight children and cognitive flexibility in three before CT (T1), then testing IQ, attention, memory and executive functions after CT (T2). The group as a whole showed no signs of any decline in IQ from T1 to T2, except for some WISC items, but IQ deteriorated severely in three patients with NF1 (only suspected in one case). At T2, the whole sample performed within normal range, except for two children showing a significantly worse result in two specific tests. The parents of the other 10 children, reported no substantial changes in their children’s behavior and intellectual vivacity in a semistructured telephone interview conducted in cooperation with the children’s teachers. CT alone as front-line treatment for CHT does not appear to have a negative effect on IQ and numerous neuropsychological tests. Some skills were more affected than others in our sample (albeit with a very low statistical significance of the impairment), and some patients seemed to be more vulnerable than others after CT. The multifactorial origin of such cognitive impairments is discussed. This type of study needs to be repeated in larger, but nonetheless carefully selected groups of patients.     

Prophylactic colony-stimulating factors in children receiving myelosuppressive chemotherapy: a meta-analysis of randomized controlled trials

BACKGROUND: The colony-stimulating factors (CSFs) are widely utilized to prevent neutropenic complications in both adults and children, but randomized controlled trials in the pediatric setting have reported varied results. A systematic review of the literature and meta-analysis were conducted to definitively assess the impact of prophylactic CSFs on the risk of febrile neutropenia (FN) in pediatric oncology patients. METHODS: MEDLINE was searched and references hand-searched through July 2004 for randomized controlled trials of prophylactic G-CSF or GM-CSF in pediatric oncology patients. Objectives, outcomes, and quality of the 16 included studies were extracted by two reviewers. Weighted summary estimates of relative risks (RR) were calculated for FN and documented infection (DI). Mean differences in hospitalization, antibiotic use, and duration of neutropenia were calculated. RESULTS: FN occurred in 68% of 400 controls and 59% of 404 CSF patients. The estimated RR was 0.88 [0.81-0.97; (P=0.01)] favoring the CSFs for leukemia and high grade lymphoma studies and 0.71 [0.51-0.97; (P=0.03)] for solid tumor studies. DI occurred in 25% of controls and 20% of CSF patients for an estimated RR of 0.80 [0.61-1.06; (P=0.12)]. The mean decrease in duration of neutropenia was 3.5 days [2.2-4.7; (P<0.0001)]. Mean decreases favoring CSF use were also observed for hospital stay of 1.7 days [0.9-2.5 (P<0.01)] and antibiotic use of 2.0 days [0.4-3.6; P=0.02]. CONCLUSIONS: Prophylactic CSFs significantly decrease the incidence of FN and the durations of severe neutropenia, hospitalization, and antibiotic use in pediatric cancer patients, but they do not significantly decrease documented infections.     

A Phase I and pharmacokinetics study of 2-chlorodeoxyadenosine in patients with solid tumors

 Preclinical studies of 2-chlorodeoxyadenosine (2-CdA) against solid tumors in the human tumor cloning assay and evidence that 2-CdA is active against slow-growing or resting tumor cells have stimulated interest in the clinical activity of this agent against solid tumors. This study sought to estimate the maximum tolerated dose, dose-limiting toxicity, and plasma and urine pharmacokinetics accompanying the intravenous administration of 2-CdA by 120-h continuous infusion in patients with solid tumors. Treated patients were also assessed for other toxicities of therapy and for antitumor response. A total of 23 patients received 35 courses of treatment given at doses of 3.5, 5.3, 6.5 and 8.1 mg/m² per day by continuous intravenous infusion for 5 days and repeated every 28 days. Blood and urine specimens were collected before, during, and after drug infusion. The dose-limiting toxicity at 8.1 mg/m² per day manifested as granulocytopenia in 2 of 5 patients (3 of 7 courses of treatment) and as thrombocytopenia in 3 of 5 patients (3 of 7 courses of treatment). At the dose levels of 6.5 and 8.1 mg/m² per day, recovery from thrombocytopenia was often delayed. Severe lymphocytopenia (<1,000/μl) was observed at all dose levels of 2-CdA. Dose-related anemia and leukopenia were observed and were infrequently severe. Nonhematological toxicities were confined to mild-to-moderate nausea, vomiting, fatigue, and anorexia. Fever of 37^°–40^°C was induced during drug infusion in 19 patients. No antitumor response was observed. Average plasma concentrations at steady-state (Cp_ss) ranged from 3 ng/ml at the initial dose level to 13 ng/ml at the dose level of 8.1 mg/m² per day. Both the Cp_ss and the area under the plasma concentration-time curve (AUC) were proportional to the dose. A relationship was observed between the percentage of change in absolute neutrophil count and the AUC. Renal excretion accounted for only 18% of the elimination of 2-CdA over the 5-day infusion period. The maximum tolerated dose for 2-CdA given by 5-day continuous infusion was 8.1 mg/m² per day in this study. The recommended dose on this schedule for phase II studies is 6.5 mg/m² per day. Granulocytopenia and thrombocytopenia were dose-limiting. No antitumor activity was observed during this study. On the basis of the plasma concentrations of 2-CdA observed, it is unlikely that this schedule of drug administration will permit achievement of the concentrations consistent with antitumor activity observed in preclinical studies. Received: 14 March 1994/Accepted: 22 July 1994     

Carboplatin pharmacokinetics in young children with brain tumors

 Purpose: The pharmacokinetic parameters and maximal tolerated systemic exposure were determined for carboplatin in young children given in combination with cyclophosphamide and etoposide. Patients and methods: Carboplatin was administered as part of a multiagent chemotherapy regimen to 21 pediatric patients less than 5 years of age with newly diagnosed, malignant central nervous system tumors. Patients received cyclophosphamide, 1.2 g/m², on day 1 and carboplatin on day 2 followed by etoposide, 100 mg/m², each day. Carboplatin doses were calculated to achieve a targeted area under the serum concentration versus time curve (TAUC) of 5, 6.5 or 8 mg/ml . min based on each patient’s measured glomerular filtration rate (GFR). Carboplatin pharmacokinetic parameters were determined after course 1 and then after every third course of therapy. Results: The median carboplatin clearance and GFR after course 1 were 118 and 98 ml/min per m², respectively. Targeted doses based on measured GFR reliably achieved the TAUC for carboplatin. The median (range) carboplatin clearance for four children less than 1 year of age was 76 (66–84) ml/min per m², significantly lower (P=0.05) than the value of 131 (80–158) ml/min per m² for children from 1 to 4 years of age. The mean carboplatin clearance declined by 23% in 12 patients studied from course 1 to course 4 of therapy. The decrease was greater than 20% (range 20–53%) in 7 of the 12 patients studied. Conclusion: Carboplatin clearance for children aged between 1 and 4 years at diagnosis is approximately 45% higher than previously reported for pediatric patients, but declines after four courses of therapy. For children less than 1 year of age, carboplatin clearance per square meter is approximately 40% lower than patients 1 to 4 years of age. There are corresponding differences in GFR that provide a plausible explanation for the age and therapy-related changes in carboplatin clearance. Toxicity was acceptable for patients treated at a TAUC of 6.5 mg/ml . min for carboplatin given with etoposide and cyclophosphamide. The average carboplatin dose required for this AUC was 767 mg/m². Received: 13 July 1995/Accepted: 18 December 1995     

Variability of 6-mercaptopurine pharmacokinetics during oral maintenance therapy of children with acute leukemia

The effects of some environmental and genetic factors on the inter- and intraindividual variations of 6-mercaptopurine (6-MP) pharmacokinetics were studied in children on oral remission maintenance therapy for acute lymphoblastic leukemia or non-Hodgkin’s lymphoma. Blood samples were obtained 0–4 h after drug intake. 6-MP concentrations were determined in plasma and in erythrocyte concentrates. The influence of food on the pharmacokinetics was examined in a prospective study of 15 children. Each child was examined four times, twice in the fasted state and twice after intake of a standardized, milky, breakfast. There were pronounced inter- and intraindividual variations. Food intake seemed to reduce these variations but there were no significant changes in peak concentrations and area under the plasma concentration vs time curves (AUC) between the fasted and fed states. Food intake reduced the time to peak concentration both in plasma, from 1.8 h to 1.1 h (P < 0.01) and in red blood cells, from 1.8 h to 1.3 h (P < 0.01). Retrospective subdivision of the patients indicated a tendency for different pharmacokinetic patterns according to dose; five out of seven patients receiving > 70 mg m⁻² had a higher AUC in the fasting state, while five out of eight patients receiving <70 mg m⁻² had a higher AUC in the fed state. The cytochrome P-450-dependent hydroxylation capacity was evaluated with debrisoquine but no correlation was found to the pharmacokinetics of 6-MP.     

Paradoxical effects of prophylactic phenothiazine antiemetics in children receiving chemotherapy

The effectiveness of prophylactic phenothiazine antiemetics on reduction of nausea and vomiting was assessed for 23 children (age, 9-17 years) who had intermittently received antiemetics (ie, for one course but not for another). Each patient was his own control and the courses with antiemetics were compared to the matched courses without antiemetics (Wilcoxon matched-pairs, signed-ranks test). In each case, the matched courses with and without antiemetics were temporally consecutive and equivalent for chemotherapeutic agents and dosages. Significantly higher ratings for severity of nausea (P less than .004), vomiting (P less than .02), and the extent to which these symptoms bothered patients (P less than .001) were found during courses with prophylactic antiemetics. Duration (in hours) of nausea and vomiting was analyzed for the last eight consecutive study patients; in eight of eight patients, a significantly longer duration of nausea (P less than .05) and vomiting (P less than .02) was found for the courses in which antiemetics were given prophylactically. This study suggests that prophylactic phenothiazine antiemetics do not predictably reduce children's nausea and vomiting and may even be associated with an increase in symptoms. Further studies in children are needed to determine which patients might benefit most from antiemetic intervention.     

Pharmacokinetics of temozolomide given three times a day in pediatric and adult patients

Purpose To characterize and compare pharmacokinetic parameters in children and adults treated with temozolomide (TMZ) administered for 5 days in three doses daily, and to evaluate the possible relationship between AUC values and hematologic toxicity.Methods TMZ pharmacokinetic parameters were characterized in pediatric and adult patients with primary central nervous system tumors treated with doses ranging from 120 to 200 mg/m² per day, divided into three doses daily for 5 days. Plasma levels were measured over 8 h following oral administration in a fasting state. A total of 40 courses were studied in 22 children (mean age 10 years, range 3–16 years) and in 8 adults (mean age 30 years, range 19–54 years).Results In all patients, a linear relationship was found between systemic exposure (AUC) and increasing doses of TMZ. Time to peak concentration, elimination half-life, apparent clearance and volume of distribution were not related to TMZ dose. No differences were seen among TMZ C_max, t_1/2, V_d or CL/F in children compared with adults. Intra- and interpatient variability of systemic exposure were limited in both children and adults. No statistically significant differences were found between the AUCs of children who experienced grade 4 hematologic toxicity and children who did not.Conclusions No difference appears to exist between pharmacokinetic parameters in adults and children when TMZ is administered in three doses daily. Hematologic toxicity was not related to TMZ AUC. AUC measurement does not appear to be of any use in optimizing TMZ treatment.     

Survival and secondary tumors in children with medulloblastoma receiving radiotherapy and adjuvant chemotherapy: results of Children's Oncology Group trial A9961

The purpose of the trial was to determine the survival and incidence of secondary tumors in children with medulloblastoma receiving radiotherapy plus chemotherapy. Three hundred seventy-nine eligible patients with nondisseminated medulloblastoma between the ages of 3 and 21 years were treated with 2340 cGy of craniospinal and 5580 cGy of posterior fossa irradiation. Patients were randomized between postradiation cisplatin and vincristine plus either CCNU or cyclophosphamide. Survival, pattern of relapse, and occurrence of secondary tumors were assessed. Five- and 10-year event-free survivals were 81 ± 2% and 75.8 ± 2.3%; overall survivals were 87 ± 1.8% and 81.3 ± 2.1%. Event-free survival was not impacted by chemotherapeutic regimen, sex, race, age at diagnosis, or gender. Seven patients had disease relapse beyond 5 years after diagnosis; relapse was local in 4 patients, local plus supratentorial in 2, and supratentorial alone in 1. Fifteen patients experienced secondary tumors as a first event at a median time of 5.8 years after diagnosis (11 >5 y postdiagnosis). All non-CNS solid secondary tumors (4) occurred in regions that had received radiation. Of the 6 high-grade gliomas, 5 occurred >5 years postdiagnosis. The estimated cumulative 10-year incidence rate of secondary malignancies was 4.2% (1.9%–6.5%). Few patients with medulloblastoma will relapse ≥5 years postdiagnosis; relapse will occur predominantly at the primary tumor site. Patients are at risk for development of secondary tumors, many of which are malignant gliomas. This may become an increasing issue as more children survive.     

An open study to assess the safety,tolerance and pharmacokinetics of an intravenous infusion of granisetron given at 3 mg over 30 s in patients receiving chemotherapy for malignant disease

Granisetron is a highly potent and selective 5-hydroxytryptamine₃ (5-HT₃) receptor antagonist indicated for the prevention of cytotoxic-induced nausea and vomiting. Clinical trials have demonstrated granisetron to be effective and well tolerated at a standard dose of 40 g/kg or 3 mg given i.v. as a 5-min infusion. In this study, the efficacy and safety of granisetron given as a 30-s infusion was assessed. A total of 21 patients, scheduled to undergo chemotherapy, received a single 3-mg i.v. dose of granisetron over 30 s, completed at 1 h before chemotherapy administration. Patients were allowed two further i.v. doses of granisetron at 3 mg within the 24-h assessment period. Changes from baseline values in vital signs were analysed prior to granisetron administration and at 30 s as well as 1, 10, 15, 30 and 60 min after granisetron administration. Holter ECG recordings were taken for 6 h prior to and 1 h after administration. No significant change was found in vital signs at 30 s or 1 min after granisetron infusion. There was a small but statistically significant fall in diastolic blood pressure as compared with baseline and a non-significant trend in favour of a reduction in heart rate at 10 and 15 min. No ECG abnormality was recorded post-infusion that had not been present pre-infusion. None of these changes was considered to be clinically relevant. The treatment was well tolerated. The most frequenctly reported adverse events were constipation (n=6) and headache (n=5). Maximal plasma levels of granisetron were within the range of 44.57–410 ng/ml except in one patient. The median values recorded for peak concentration (C_max) and area under the curve (AUC) were 195 ng/ml and 71.2 ng h ml^–1, respectively. In conclusion, granisetron at 3 mg was shown to be safe and well tolerated when given as a 30-s i.v. infusion to patients receiving chemotherapy for malignant disease.     

Effect of hepatic irradiation on the toxicity and pharmacokinetics of adriamycin in children

The effect of hepatic irradiation on adriamycin toxicity and pharmacokinetics was studied in 10 children who received adriamycin with concurrent abdominal irradiation for Wilms' tumor. Hepatic irradiation to 2400–2700 rad at 100–150 rad per fraction did not alter the clinical toxicity or plasma pharmacokinetics of adriamycin.     

The effects of ondansetron and granisetron on electrocardiography in children receiving chemotherapy for acute leukemia

5-HT3 receptor antagonists, including granisetron and ondansetron, are widely used in the prophylactic treatment of chemotherapy-induced nausea and vomiting. Although the cardiac safety of granisetron and ondansetron has been investigated in several adult studies, there is no report investigating the effects of those agents on electrocardiography (ECG) in children. The effects of intravenously infused (over 30 seconds) 0.1 mg/kg ondansetron and 40 microg/kg granisetron on ECG were assessed in 22 children receiving high-dose methotrexate therapy for acute lymphoblastic leukemia. The ECG recording was obtained at before and just after the infusion, and repeated at 1, 3, 6, and 24 hours of treatment. Granisetron administration resulted in a statistically significant decrease of mean heart rate at 1 and 3 hours, and significant prolongation of mean QT and QTc dispersions at 1 hour of infusion. In patients treated with ondansetron, no meaningful change was observed. In conclusion, intravenous granisetron but not ondansetron causes clinically asymptomatic and transient changes on ECG measurements in children receiving high-dose methotrexate therapy.     

Cyclophosphamide pharmacokinetics and pharmacogenetics in children with B-cell non-Hodgkin's lymphoma

IntroductionVariation in cyclophosphamide pharmacokinetics and metabolism has been highlighted as a factor that may impact on clinical outcome in various tumour types. The current study in children with B-cell non-Hodgkin's lymphoma (NHL) was designed to corroborate previous findings in a large prospective study incorporating genotype for common polymorphisms known to influence cyclophosphamide pharmacology.MethodsA total of 644 plasma samples collected over a 5 year period, from 49 B-cell NHL patients ≤18 years receiving cyclophosphamide (250 mg/m²), were used to characterise a population pharmacokinetic model. Polymorphisms in genes including CYP2B6 and CYP2C19 were analysed.ResultsA two-compartment model provided the best fit of the population analysis. The mean cyclophosphamide clearance value following dose 1 was significantly lower than following dose 5 (1.83 ± 1.07 versus 3.68 ± 1.43 L/h/m², respectively; mean ± standard deviation from empirical Bayes estimates; P < 0.001). The presence of at least one CYP2B6*6 variant allele was associated with a lower cyclophosphamide clearance following both dose 1 (1.54 ± 0.11 L/h/m² versus 2.20 ± 0.31 L/h/m², P = 0.033) and dose 5 (3.12 ± 0.17 L/h/m² versus 4.35 ± 0.37 L/h/m², P = 0.0028), as compared to homozygous wild-type patients. No pharmacokinetic parameters investigated were shown to have a significant influence on progression free survival.ConclusionThe results do not support previous findings of a link between cyclophosphamide pharmacokinetics or metabolism and disease recurrence in childhood B-cell NHL. While CYP2B6 genotype was shown to influence pharmacokinetics, there was no clear impact on clinical outcome.     

Clinical and pharmacokinetic study evaluating the effect of food on the disposition of 9-nitrocamptothecin and its 9-aminocamptothecin metabolite in patients with solid tumors

Background: 9-Nitrocamptothecin (9NC) is an orally administered camptothecin analogue that has completed phase III trials for pancreatic cancer. In biological matrices, camptothecin analogues exist in equilibrium between the active-lactone (LAC) and inactive-hydroxy acid (HA) forms. 9NC has been administered on an empty stomach; however, it is unclear if food alters the absorption and disposition of 9NC and its 9-aminocamptothecin (9AC) active-metabolite. Thus, we evaluated the disposition of 9NC and 9AC after administration of 9NC under fasting conditions and after a standard meal. Methods: Patients were randomized to receive 9NC as a single oral dose at 1.5 mg/m² with 8 ounces (oz) of an acidic beverage under fasting conditions, or after a meal consisting of two eggs, 8 oz of orange juice, buttered toast, 8 oz of milk, and 4 oz of hash brown potatoes. Following a 72 h washout period, 9NC was administered with the alternative condition (i.e., with food or fasting). 9NC was then continued for 5 days of every week. Serial blood samples were obtained prior to and from 0.25 to 24 h after administration of 9NC. The total (sum of LAC + HA) of 9NC and 9AC were measured by an LC-MS/MS assay. Area under the plasma concentration versus time curve (AUC) for 9NC and 9AC total were calculated. After the pharmacokinetic section of the study, patients received 9NC 1.5 mg/m² orally under fasting conditions daily for 5 days per week for 8 weeks. Results: Sixteen patients with median (range) age 62 (47–83) years, diagnoses of colorectal (six patients), lung (two patients), and other (eight patients) malignancies, received 83 [median (range) 4 (2–9)] weeks of therapy. Patients with toxicities greater than grade 2: were diarrhea (1), nausea (2), vomiting (2), fatigue (2), anemia (3), neutropenia (3), and febrile neutropenia (2). Three patients (lung, unknown primary, and colon) had stable disease for eight weeks. The mean±SD of 9NC AUC_food and 9NC AUC_fast (n=9) were 330±182 and 558±379 ng/ml·h, respectively (P<0.05). The mean±SD of 9AC AUC_food and 9AC AUC_fast (n=9) were 244±60 and 256±101 ng/ml·h, respectively (P>0.05). The mean ± SD ratio of 9NC AUC_food to AUC_fasting in individual patients (n=9) was 0.67±0.22. The mean ± SD ratio of 9AC AUC_food to AUC_fasting in individual patients (n=9) was 1.14±0.61. Conclusions: Co-administration of 9NC with food reduces the oral absorption of 9NC; however, there was no difference in the exposure of 9AC. The is high interpatient variability in the effect of food on the absorption of 9NC and the interpatient variability in the effect of food on the disposition of 9AC is even greater when compared to 9NC. Supported, in part, by grant NCI 2P30 CA47904, grant NIH / NCRR / GCRC /#5M01 RR00056, and a grant from Supergen Inc., Dublin, California     

Granulocyte-colony stimulating factor and multiple cycles of strongly myelosuppressive alkylator-based combination chemotherapy in children with neuroblastoma

BACKGROUND: The authors assessed key effects of granulocyte-colony stimulating factor (G-CSF) used prophylactically with multiple cycles of strongly myelosuppressive alkylator-based combination chemotherapy. To the authors' knowledge, no large study has focused on G-CSF in this setting, yet this kind of treatment has recently become standard for poor risk pediatric solid tumors such as neuroblastoma. PATIENTS AND METHODS. Children with neuroblastoma received cyclophosphamide 140 mg/kg (i.e., 4200 mg/m(2)), doxorubicin 75 mg/m(2), and vincristine (CAV) in cycles 1, 2, 4, and 6 and cisplatin 200 mg/m(2) and etoposide 600 mg/m(2) (P/VP) in cycles 3, 5, and 7. To maximize dose intensity, chemotherapy was begun as soon as the absolute neutrophil count (ANC) was > or = 500/microL and platelet count was > or = 100,000/microL. No cytokines were used during 1990-1994 (control group; n = 28), but G-CSF was used from 1995 to 1998 (G-CSF group; n = 30) at 5 microg/kg/day subcutaneously from 1 day after chemotherapy until the ANC was > or = 500/microL on 2 successive days or was > or = 1000/microL. RESULTS: Each cycle of CAV decreased ANCs to < 200/microL in all 58 patients; recovery to 200/microL and to 500/microL was significantly sooner with G-CSF. In contrast, P/VP did not invariably cause severe neutropenia: similar numbers of patients in each group maintained ANCs > or = 200/microL and > or = 500/microL; recovery to 500/microL (but not to 200/microL) was significantly faster in the G-CSF group. G-CSF had no impact on rates of febrile episodes. Bacterial/fungal infections were slightly less frequent in the G-CSF group with CAV (P = 0.11) but not with P/VP. Dose intensity through cycle 4 was the same in both groups. Beginning with cycle 3, G-CSF patients had slower recovery to platelet counts > or = 100,000/microL. Response rates were similar in the two groups. CONCLUSIONS: With multiple cycles of strongly myelosuppressive alkylator-based combination chemotherapy, prophylactic use of G-CSF hastened ANC recovery but did not reduce the incidence of febrile episodes, had little impact on infection rates, did not yield augmented dose intensity, was associated with prolonged thrombocytopenia, and had no effect on response rates of neuroblastoma. The data support more limited use of G-CSF.     

Clinical pharmacokinetics of carboplatin in children

The present study was undertaken to evaluate in children the plasma pharmacokinetics of free carboplatin given at different doses and schedules and to evaluate the inter- and intrapatient variability and the possible influence of schedule on drug exposure. A total of 35 children (age range, 1–17 years) with malignant tumors were studied. All patients had normal renal function (creatinine clearance corrected for surface body area, above 70 ml min^–1 m^–2; range, 71–151 ml min^–1 m^–2) and none had renal involvement by malignancy. Carboplatin was given at the following doses and schedules: 175, 400, 500, and 600 mg/m² given as a 1-h infusion; 1,200 mg/m² divided into equal doses and infused over 1 h on 2 consecutive days; and 875 and 1,200 mg/m² given as a 5-day continuous infusion. A total of 57 courses were studied. Carboplatin levels in plasma ultrafiltrate (UF) samples were measured both by high-performance liquid chromatography and by atomic absorption spectrophotometry. Following a 1-h infusion, carboplatin free plasma levels decayed biphasically; the disappearance half-lives, total body clearance, and apparent volume of distribution were similar for different doses. In children with normal renal function as defined by creatinemia and blood urea nitrogen (BUN) and creatinine clearance, we found at each dose studied a limited interpatient variability of the peak plasma concentration (C_max) and the area under the concentration-time curve (AUC) and a linear correlation between the dose and both C_max (r=0.95) and AUC (r=0.97). The mean value ± SD for the dose-normalized AUC was 13±2 min m² l^–1 (n=57). The administration schedule does not seem to influence drug exposure, since prolonged i.v. infusion or bolus administration of 1,200 mg/m² achieved a similar AUC (13.78±2.90 and 15.05±1.44 mg ml^–1 min, respectively). In the nine children studied during subsequent courses a limited interpatient variability was observed and no correlation (r=0.035) was found between AUC and subsequent courses by a multivariate analysis of dose, AUC, and course number. The pharmacokinetic parameters were similar to those previously reported in adults; however, a weak correlation (r=0.52,P=0.03) between carboplatin total body clearance and creatinine clearance varying within the normal range was observed. A dosing formula appears unnecessary in children with normal renal function since a generally well-predictable free carboplatin AUC is achieved following a given dose.Supported by the Associazione Italiana per la Ricerca sul Cancro (A.I.R.C.)     

Enhanced Proliferative Activity of PIXY-321, the Granulocyte-Macrophage Colony-Stimulating Factor and Interleukin-3 Fusion Protein

Previous studies with the granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) fusion protein, PIXY-321, demonstrated the enhanced biological activity of this molecule in comparison with GM-CSF or IL-3 alone or in combination. Here, we performed experiments to determine the proliferative effect of PIXY-321 on 13 constitutively growth factor-dependent human leukemia cell lines in comparison with GM-CSF, IL-3 and their combination using as read-out parameters the 48-hour ³H-thymidine incorporation assay and viable cell counts after in vitro culture for 7-8 days. Whereas one cell line was not responsive to any of these three cytokines, the other 12 cell lines showed variable degrees of growth in response to these effector molecules. PIXY-321 increased proliferation as measured by thymidine uptake relative to IL-3, GM-CSF or GM-CSF + IL-3 by 34% (range 5-448%), 12% (range 0-122%), and 6% (range 1-13%), respectively. PIXY-321 induced a mean increase of 32%, 30% and 11% in cell counts relative to the values obtained with IL-3, GM-CSF or GM-CSF + IL-3, respectively. Altogether, these data indicate that PIXY-321 stimulates proliferation of immature hematopoietic cells substantially better than equivalent concentrations of the single growth factors GM-CSF and IL-3. This hybrid growth factor showed a marginal to modest, but definite and reproducible increase in proliferation compared to the combination of GM-CSF plus IL-3. In summary, the fusion cytokine protein PIXY-321 appears to have biological effects superior to those elicited by its components, singly or in combination. This unique molecule should represent a useful tool in studies on the mechanisms underlying cytokine ligand-receptor interaction and the subsequent signal transduction. The use of PIXY-321 provides an opportunity for taking greater advantage in vitro and in vivo of the hematopoietic stimulatory activities of GM-CSF and IL-3.     

A dose escalation and pharmacokinetic study of biweekly pegylated liposomal doxorubicin, paclitaxel and oxaliplatin in patients with advanced solid tumors

PURPOSE: To evaluate the maximum tolerated doses (MTD) and the dose-limiting toxicities (DLT) of the combination of pegylated liposomal doxorubicin (PEG-LD), paclitaxel and oxaliplatin (L-OHP) administered every 2 weeks in patients with advanced solid tumors. METHODS: Thirty-nine pretreated patients with advanced solid tumors received escalated doses of PEG-LD (10-16 mg/m(2)), paclitaxel (100-120 mg/m(2)) and L-OHP (50-70 mg/m(2)) every 2 weeks. As one cycle of treatment was considered the administration of both drugs on days 1 and 15 of a 4-week cycle. RESULTS: The MTDs were PEG-LD 14 mg/m(2), paclitaxel 120 mg/m(2) and L-OHP 70 mg/m(2). Neutropenia was the DLT in all but one case with only one episode of febrile neutropenia and no toxic deaths. Four (4%) and 13 (12%) cycles were complicated by grades 4 and 3 neutropenia, respectively. Grades 2-3 fatigue and neurotoxicity occurred in 13 and 12% of cycles, respectively. Responses were observed in patients with breast, endometrial and ovarian carcinomas. CONCLUSIONS: This is a quite well-tolerated regimen which merits further evaluation in phase II studies.