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G Vassal

Publications and source records attributed to G Vassal.

At least 73 records · Page 4Linked to original sources
PubMed1993

Busulfan disposition below the age of three: alteration in children with lysosomal storage disease.

Busulfan disposition is age-dependent with a higher clearance and a larger volume of distribution in children than in adults. The optimal dosage of busulfan needed to achieve bone marrow (BM) displacement in young children with malignant or nonmalignant disease remains to be defined. Using a gas chromatography-mass spectrometry assay, we evaluated plasma pharmacokinetics of busulfan in 33 children (median age, 9 months; range, 2 months to 2.75 years) with immune deficiencies, lysosomal storage diseases, acute leukemias, and malignant lymphohistiocytosis after an oral dose ranging from 0.9 to 2.6 mg/kg. The busulfan clearance (assuming a bioavailability of 1) ranged from 2.1 to 13.4 mL/min/kg with a mean of 6.8 mL/min/kg, which is higher than that reported in older children (4.5 mL/min/kg) and adults (2.9 mL/min/kg). Six children with lysosomal storage disease (5 with Hurler's disease, 1 with San Filippo's disease) had a prolonged elimination half-life (4.9 v 2.4 hours), a larger volume of distribution (3.4 v 1.2 L/kg) and a faster clearance (8.7 v 6.3 mL/min/kg) than the other 27 children. This suggests that a higher dose of busulfan will be required to achieve BM displacement in children with lysosomal storage disease. Over the dose range of 0.9 to 2.6 mg/kg, busulfan pharmacokinetics were linear. However, only 46% of the interpatient variation in systemic exposure could be ascribed to the dose. Given the wide interpatient variability in busulfan disposition, dose adjustment and drug monitoring will be needed to achieve the optimal dosage of busulfan in young children. The plasma busulfan levels required to achieve BM displacement need to be defined, especially in lysosomal storage diseases.

Age Factors↗
PubMed1993

Chronopharmacology of high-dose busulfan in children.

In bone marrow transplantation, high-dose busulfan is given p.o., usually every 6 h over 4 consecutive days. Since this repeated administration might alter busulfan disposition, fluctuations in busulfan plasma levels were studied over the 4-day treatment period in 21 children (median age, 5 years) with malignant solid tumors. In addition, urinary excretion of unchanged busulfan was measured every 6 h in 4 patients. Busulfan (37.5 mg/m2 for 16 doses) was given on an empty stomach at 12 p.m., 6 p.m., midnight, and 6 a.m. for 4 consecutive days, starting at 12 p.m. Trough plasma levels, i.e., concentration 6 h after each dose and just before the next one, and urinary excretion of busulfan were measured using a gas chromatography-mass spectrometry assay. Busulfan trough plasma levels exhibited a significant circadian rhythm with a higher mean level at 6 a.m. compared to that at 12 p.m., 6 p.m., and midnight. This rhythm was characterized by a double amplitude (mean +/- SD) of 42 +/- 14% and an acrophase (maximum) occurring at 5:48 a.m. +/- 115 min. In addition, once the steady state was reached, no decreasing trend was observed in any patient. Busulfan renal clearance proved to be low since only 5.4 +/- 1.2% of the given dose were excreted unchanged in urine. In the 4 patients studied, busulfan urinary excretion exhibited a significant circadian rhythm which was apparently linked to the physiological circadian rhythm in urinary output. Ten of 20 evaluable patients developed hepatic venoocclusive disease (HVOD). A significant circadian rhythm in the plasma level was found in both HVOD and non-HVOD patients with no difference between the two groups with regard to the 24-h mean, amplitude, or acrophase. Thus, the circadian changes in busulfan trough plasma levels observed at the steady state were not related to the occurrence of HVOD in these children with solid tumors. Moreover, since this rhythm was stable from day 2 to day 4, it should not compromise dose adjustment.

Bone Marrow Transplantation↗
PubMed1993

Combined continuous infusion etoposide with high-dose cyclophosphamide for refractory neuroblastoma: a phase II study from the Société Française d'Oncologie Pédiatrique.

PURPOSE: Patients older than 1 year with stage IV neuroblastoma who fail to achieve complete remission (CRem) have a particularly poor long-term prognosis. In an attempt to improve the outcome of these refractory patients, we tested a new drug combination. PATIENTS AND METHODS: Twenty-nine children with advanced neuroblastoma (27 stage IV and two stage III) were entered onto this phase II study. All were refractory to conventional chemotherapy and had measurable disease at the time of the trial. The regimen was a combination of high-dose cyclophosphamide (2 g/m2/d) on days 2, 3, and 4, and etoposide (VP16; 50 mg/m2/d) by continuous intravenous (IV) infusion on days 1 to 5. A pharmacokinetic study of VP16 was conducted in eight patients to determine whether the goal of persistent plasma levels between 1 and 5 micrograms/mL was achieved. RESULTS: Patients received a median of two courses, for a total of 58 courses. The median interval between each course was 32 days. In the 28 assessable patients, the overall response rate was 43%, with one CRem and 11 partial remissions (PRems). No life-threatening complication was observed in these heavily pretreated patients. The median duration of neutropenia (< 5 x 10(9)/L) was 14 days, and that of thrombocytopenia (< 50 x 10(9)/L) was 11 days. The overall incidence of sepsis was 27%. Gastrointestinal toxicity was frequent, but mild. Electrolyte disturbance with antidiuretic hormone (ADH)-like syndrome occurred in eight courses, but resolved rapidly. Grade > or = 2 hemorrhagic cystitis was observed in three courses. No cardiac toxicity was observed. There were no treatment-related deaths. Pharmacokinetic analysis showed that mean steady-state plasma levels (Css) of VP16 were greater than 1 microgram/mL during all the courses. CONCLUSION: This new drug combination appears to be effective in advanced neuroblastoma. Its toxicity remains manageable, with no life-threatening complications. Further evaluation in patients with less-advanced disease is warranted.

Adolescent↗
PubMed1992

Is 600 mg/m2 the appropriate dosage of busulfan in children undergoing bone marrow transplantation?

Recent studies have reported that the pharmacokinetics of high-dose busulfan in bone marrow transplantation (BMT) are age-dependent: with the usual dosage of 16 mg/kg over 4 days, systemic exposure is two to four times lower in children than in adults. Data suggested that the dose of busulfan should rather be calculated on the basis of the body surface area (BSA). We measured plasma pharmacokinetics of busulfan in 27 children (mean age, 5.4 years) who were administered a new dosage of 600 mg/m2 over 4 days, ie, 17.8 to 29.2 mg/kg (mean, 24.8 mg/kg), using a gas chromatography-mass spectrometry assay. Our results demonstrate that, with this new dosage, systemic exposure is significantly increased in children compared with that achieved with the usual dosage of 16 mg/kg (6,404 +/- 2,378 v 3,918 +/- 1,170 ng.h/mL; P = .003). Moreover, there is no longer a significant difference in systemic exposure between children treated with this new dosage and adults given a dose of 16 mg/kg of busulfan. However, despite the use of a dosage normalized to the BSA, there is still a wide interindividual variation in systemic exposure, ranging from 3,566 to 13,129 ng.h/mL, which may account for the high incidence of venoocclusive disease (VOD) of the liver that we have already reported. The optimal dosage and schedule of busulfan in children requires a more individual approach that could be based on dose adjustment and plasma level monitoring.

Adolescent↗
PubMed1992

[Granulosa cell tumors of the ovary in children and adolescents. Multicenter retrospective study in 40 patients aged 7 months to 22 years].

BACKGROUND: Juvenile granulosa cell tumors (JGCT) of the ovary are rare in children. The over-all outcome after surgery is relatively good, but the indication and type of complementary treatment for severe forms are still unclear. POPULATION: A retrospective survey of the majority of patients with JGCT of the ovary admitted between 1965 and 1990 to 11 French oncologic pediatric centers was carried out. Medical records including surgical and histological data, were analyzed and each tumor was retrospectively classified by the same pathologist according to the Wollner classification. RESULTS: There were 40 patients aged 7 months to 22 years (mean: 6 years); 28 were less than 10 year old at diagnosis. Three had enchondromatosis (Ollier's disease). At diagnosis, all patients presented with an abdominal tumor, 23 had developed manifestations of precocious pseudopuberty, 2 had signs of virilization after a normal puberty and 2 had secondary amenorrhea. Surgery was always the primary treatment: unilateral ovariectomy in 35 cases, bilateral in 4 and biopsy alone in 1 case. There were 21 stage I, 1 stage II, 16 stage III and 2 stage IV cases. 13 patients received combined chemotherapy and 2 abdominal radiotherapy. 34 patients were alive and disease-free 10 months to 26 years after surgery and 6 died. All 23 patients with precocious pseudopuberty had a favorable outcome. CONCLUSIONS: This study confirms earlier reports. Unilateral ovariectomy is the first-choice therapy. There is no evidence that tumors complicated by rupture and hemoperitoneum require chemotherapy. Combined chemotherapy does not appear to improve the prognosis for the rare malignant forms. The factors of good prognosis are age less than 10 years and the presence of precocious pseudopuberty.

Adolescent↗
PubMed1992

Risk factors for hepatic veno-occlusive disease after high-dose busulfan-containing regimens followed by autologous bone marrow transplantation: a study in 136 children.

Risk factors for hepatic veno-occlusive disease (HVOD) were analysed in a population of 136 autografted children who received high-dose busulfan (BU) as part of a conditioning regimen. HVOD was diagnosed according to McDonald's clinical criteria. The incidence of HVOD was particularly high in this series (22%) compared with series with other conditioning regimens but the outcome was favorable in 26 patients (87%). Four deaths occurred (13%), one of which was HVOD related. The clinical presentation of HVOD was similar to that described in previous reports. Although statistical analysis failed to demonstrate any factors predictive of outcome, it did identify risk factors for the occurrence of HVOD: these were (1) a total dose of BU exceeding the standard 16 mg/kg dose; (2) the use of three as opposed to two alkylating agents; (3) the sequence of BU administration when given in the conditioning regimen containing three alkylating agents; and (4) concomitant ketoconazole therapy.

Adolescent↗
PubMed1992

High-dose busulfan and thiotepa with autologous bone marrow transplantation in childhood malignant brain tumors: a phase II study.

In order to evaluate the effect of intensive combined chemotherapy in pediatric brain tumors, we designed a phase II study of high-dose busulfan and thiotepa followed by bone marrow transplantation (BMT) in children with measurable recurrent brain tumors. As alkylating agents, busulfan and thiotepa were expected to exhibit a steep dose effect and no overlapping extramedullary toxicity. Moreover, both drugs have an excellent distribution into the central nervous system in humans. Since May 1988, 20 children (median age 6 years) have been treated. Busulfan (150 mg/m2/day x 4) given orally was followed by thiotepa (350 mg/m2/day x 3), given as a 1 h i.v. infusion. Cryopreserved bone marrow was reinfused 48 h after completion of chemotherapy. Tumor response was assessed by computed tomography and magnetic resonance imaging 4 to 6 weeks after BMT. Five partial responses were observed (three of six medulloblastomas, one of five ependymomas, one of two primitive neuroectodermal tumors); two patients with medulloblastoma and one with brain stem tumor achieved an objective response. Ten patients had stable disease and one progressive disease. One patient is not evaluable because of early toxic death. Toxicity was high in terms of aplasia and cutaneous, hepatic and neurological complications. The overall response rate of 26% is encouraging since all patients had disease refractory to all conventional therapies.

Adolescent↗
PubMed1991

Treatment of stage IV-S neuroblastoma: a study of 34 cases treated between 1982 and 1987.

Between January 1982 and December 1987, of 283 children with neuroblastoma treated in the Pediatric Department of Institut Gustave Roussy, 34 were stage IV-S. Two groups were distinguished according to the initial clinical presentation: 16/34 patients had life-threatening symptoms and needed immediate treatment, and 18/34 had no life-threatening symptoms. Hepatic irradiation was used in 12/16 patients of the first group with respiratory distress. Chemotherapy was used in three patients. Of these 16 patients, three patients died of progressive disease (one patient died of a reason not related to the tumor). Twelve are alive in first complete remission and one in second complete remission. Of the 18 patients of the second group, eight had spontaneous complete remission, and one of them relapsed thereafter and died despite treatment. Ten patients needed treatment, radiotherapy, and/or chemotherapy depending on the site of disease progression. Two of them died of the disease. The overall disease-free survival for these 34 patients is 75% at 90 months postdiagnosis. Using this therapeutic strategy, it was possible to avoid any treatment of metastases in 25% of the patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

High-dose chemotherapy containing busulfan followed by bone marrow transplantation in 24 children with refractory or relapsed non-Hodgkin's lymphoma.

Twenty-four children with relapsed or refractory non-Hodgkin's lymphoma underwent high-dose chemotherapy (HDC) with bone marrow transplantation (BMT). HDC comprised in all cases busulfan (16 mg/kg or 600 mg/m2), with either cyclophosphamide (200 mg/kg or 4.4 g/m2) and/or melphalan (140 mg/m2). Twenty-three of these children had received second-line therapy before receiving HDC. There were 16 B cell and eight T cell lymphomas. Twenty-three patients were evaluable at day 30 post-BMT; 19 were in complete remission, four did not respond. Eight patients are long-term survivors between 62 and 296 weeks after BMT. Among the seven children with resistant disease before HDC, only one is a long-term survivor. No toxic deaths occurred. The main adverse side effect was hepatic veno-occlusive disease which occurred in four patients, but resolved completely in all cases. Comparisons with other classic HDC regimens in relapsed childhood lymphomas show that HDC containing busulfan with BMT appears reasonably safe and is effective in refractory or relapsed lymphomas, even in these highly previously treated patients.

Adolescent↗
PubMed1991

Streptococcal septicaemia following autologous bone marrow transplantation in children treated with high-dose chemotherapy.

A total of 251 patients were given 326 courses of high-dose chemotherapy followed by autologous bone marrow transplantation between February 1979 and August 1988. Ninety-one cases of septicaemia developed in 84 patients, 33 of these cases (36%) were due to streptococci. The outcome was fatal for four patients (12.1%). No specific risk factors were identified which might account for this septicaemia and no clinical feature was significantly associated with these cases of bacterial infection. Pulmonary and neurologic septic complications, however, were of very poor prognosis since all patients with these complications died. The high rate of streptococcal septicaemia and the poor outcome for patients with prolonged and profound neutropenia led us to modify our choice of initial broad-spectrum antibiotic therapy.

Adolescent↗
PubMed1990

Dose-dependent neurotoxicity of high-dose busulfan in children: a clinical and pharmacological study.

Busulfan is known to be neurotoxic in animals and humans, but its acute neurotoxicity remains poorly characterized in children. We report here a retrospective study of 123 children (median age, 6.5 years) receiving high-dose busulfan in combined chemotherapy before bone marrow transplantation for malignant solid tumors, brain tumors excluded. Busulfan was given p.o., every 6 hours for 16 doses over 4 days. Two total doses were consecutively used: 16 mg/kg, then 600 mg/m2. The dose calculation on the basis of body surface area results in higher doses in young children than in older patients (16 to 28 mg/kg). Ninety-six patients were not given anticonvulsive prophylaxis; 7 (7.5%) developed seizures during the 4 days of the busulfan course or within 24 h after the last dosing. When the total busulfan dose was taken into account, there was a significant difference in terms of neurotoxicity incidence among patients under 16 mg/kg (1 of 57, 1.7%) and patients under 600 mg/m2 (6 of 39, 15.4%) (P less than 0.02). Twenty-seven patients were given a 600-mg/m2 busulfan total dose with continuous i.v. infusion of clonazepam; none had any neurological symptoms. Busulfan levels were measured by a gas chromatographic-mass spectrometry assay in the plasma and cerebrospinal fluid of 9 children without central nervous system disease under 600 mg/m2 busulfan with clonazepam:busulfan cerebrospinal fluid:plasma ratio was 1.39. This was significantly different (P less than 0.02) from the cerebrospinal fluid:plasma ratio previously defined in children receiving a 16-mg/kg total dose of busulfan. This study shows that busulfan neurotoxicity is dose-dependent in children and efficiently prevented by clonazepam. A busulfan dose calculated on the basis of body surface area, resulting in higher doses in young children, was followed by increased neurotoxicity, close to neurotoxicity incidence observed in adults. Since plasma pharmacokinetic studies showed a faster busulfan clearance in children than in adults, this new dose may approximate more closely the adult systemic exposure obtained after the usual 16-mg/kg total dose, with potential inferences in terms of anticancer or myeloablative effects. The busulfan dose in children and infants undergoing bone marrow transplantation should be reconsidered on the basis of pharmacokinetic studies.

Adolescent↗
PubMed1990

Brain tumours under the age of three. The price of survival. A retrospective study of 20 long-term survivors.

Between 1975 and 1989, 98 children with brain tumours under the age of three at time of diagnosis were entered into a retrospective study. Twenty of them are alive and free of tumour more than five years after treatment and were evaluated in this study. Thirteen tumour localizations were infratentorial and 7 were supratentorial. A histological examination was performed in 15 patients: 5 ependymomas, 6 medulloblastomas and 4 astrocytomas were identified. Fifteen patients underwent surgical removal of tumour, all but one received radiotherapy and 8 were given chemotherapy. Only two children have not late effects. Analysis of long-term sequelae in survivors showed central endocrinopathies in 14 (70%), a neurological handicap in 13 (65%) and impaired cognitive functions in 17 (85%). Irradiation was clearly responsible for mental sequelae in 7 patients and endocrinopathies in 6 patients. The other possible causes are tumour injury, hydrocephalus or surgery. The risks incurred with radiotherapy and advances in infant brain tumour therapy are discussed.

Adolescent↗
PubMed1990

Cerebrospinal fluid and plasma methotrexate levels following high-dose regimen given as a 3-hour intravenous infusion in children with nonHodgkin's lymphoma.

In the French nonHodgkin's lymphoma protocols, central nervous system prophylaxis is provided by high-dose methotrexate (HD-MTX), given as a 3-hour IV infusion of 3 g/m2 MTX along with intrathecal MTX injection. The incidence of CNS relapse is less than 3%. We designed a study to evaluate the MTX transfer across the blood brain barrier in terms of cytotoxic concentrations, during these short-term infusions. Cerebrospinal fluid and plasma MTX levels were measured during 61 courses in 29 children with nonHodgkin's lymphoma; none of them had central nervous system disease. Samples were obtained either 4, 12, 18, or 24 hours after the start of HD-MTX IV infusion. A potentially cytotoxic MTX level (10(-6)M) was reached in all courses at 4 hours (median: 2.3 X 10(-6)M) and remained available in 8/16 courses at 12 hours (median: 1.0 X 10(-6)M) and in only 2/17 courses at 18 hours (median: 0.29 X 10(-6)M). Twenty-four hours after the start of HD-MTX IV infusion, CSF MTX level was always less than 10(-6)M. The plasma MTX levels were 260, 1.3, 1.0, and 1.7 X 10(-6)M at 4, 12, 18, and 24 hours, respectively. There was no correlation between plasma and CSF MTX levels. These data show that potentially cytotoxic MTX concentrations can be reached in CSF after a 3-hour IV infusion of 3 g/m2 in every patient and remain available for at least 8 hours in half of them.

Adolescent↗
PubMed1990

[Pharmacologic bases of chemotherapy of brain tumors in children].

In terms of pharmacology, drug delivery is an important obstacle in the development of brain tumor chemotherapy. The blood-brain barrier limits the drug penetration in normal brain tissue around the tumor and at distant potential metastatic sites. In the tumor, the altered blood-brain barrier, ie blood-tumor barrier, decreases the drug entry in malignant cells. The knowledge of the blood-brain barrier physiology and the definition of the laws that govern the drug delivery to the central nervous system allow the development of new strategies to increase drug delivery to the tumor. In pediatric oncology, the more appropriate methods are the use of anticancer agents that easily cross the blood-brain barrier and the development of high-dose systemic chemotherapy regimens with or without bone marrow rescue.

Antineoplastic Agents↗
PubMed1990

[Role of high-dose chemotherapy followed by bone marrow autograft in the treatment of metastatic Ewing's sarcoma in children].

Thirty-two children were treated for metastatic Ewing sarcoma by high-dose chemotherapy followed by autologous bone marrow transplantation. Fourteen patients entered phase II studies of high-dose alkylating agents. The response rate observed was 61%. High-dose chemotherapy was used as consolidation in complete remission of 18 patients. Disease free survival appears to be better than that observed under conventional altered chemotherapy. However, with only 4/18 long term survivors, these results remain unsatisfactory, taking into account the recent encouraging results of semi-continuous conventional chemotherapy.

Adolescent↗