Busulfan disposition and hepatic veno-occlusive disease in children undergoing bone marrow transplantation

Hepatic veno-occlusive disease (HVOD) is a frequent life-threatening toxicity in patients undergoing bone marrow transplantation (BMT) after the administration of a high-dose busulfan-containing regimen. Recent studies have shown that the morbidity and mortality of HVOD may be reduced in adults by pharmacologically guided dose adjustment of busulfan. We analyzed the pharmacodynamic relationship between busulfan disposition and HVOD in 61 children (median age, 5.9 years) with malignant disease. Busulfan, given at a dose ranging from 16 mg/kg to 600 mg/m2, was combined with one or two other alkylating agents (cyclophosphamide, melphalan, thiotepa). Only 3 patients received the standard busulfan/cyclophosphamide (BUCY) regimen. A total of 24 patients (40%) developed HVOD, which resolved in all cases. A pharmacokinetics study confirmed the previously reported wide interpatient variability in busulfan disposition but did not reveal any significant alteration in children with HVOD. The mean area under the concentration-time curve (AUC) after the first dose of busulfan was higher in patients with HVOD (6,811 +/- 2,943 ng h ml-1) than in patients without HVOD (5,760 +/- 1,891 ng h ml-1., P = 0.10). This difference reflects the higher dose of busulfan given to patients with HVOD. No toxic level could be defined and, moreover, none of the toxic levels identified in adults were relevant. The high incidence of HVOD in children given 600 mg/m2 busulfan may be linked to the use of more intensive than usual high-dose chemotherapy regimens and/or drug interactions. Before the prospective evaluation of busulfan dose adjustment in children, further studies are required to demonstrate firmly the existence of a pharmacodynamic relationship in terms of toxicity and allogeneic engraftment, especially when busulfan is combined with cyclophosphamide. The maximal tolerated and minimal effective AUCs in children undergoing BMT are likely to depend mainly upon the disease, the nature of the combined high-dose regimen, and the type of bone marrow transplant.

New strategies for the application of high-dose chemotherapy with haematopoietic support in paediatric solid tumours

Because paediatric solid tumours are usually highly chemosensitive, conventional-dose adjuvant chemotherapy has improved survival rates for the majority of paediatric patients. However, high-dose regimens are being explored for the treatment of tumours not curable by, or resistant to, conventional treatment. The use of high-dose melphalan and the BACT regime have produced encouraging results in neuroblastoma and Ewing's sarcoma, and non-Hodgkin's lymphoma respectively. Haematopoietic growth factors have also emerged as useful adjuncts both to conventional therapy and in megatherapy with bone marrow transplantation (BMT). Thus, granulocyte colony-stimulating factor (G-CSF) (filgrastim) given to children with disseminated neuroblastoma receiving intensive chemotherapy significantly reduced the duration of febrile neutropenia and led to significantly fewer cycles of chemotherapy requiring antibiotic support. Studies are currently underway to compare the use of autologous BMT with that of peripheral blood progenitor cell (PBPC) rescue in children with solid tumours receiving high-dose chemotherapy. The studies will explore the reduction in thrombocytopenia achievable with PBPC and also the effect of filgrastim on the duration of neutropenia and fever. It seems that haematopoietic growth factors have an important supportive role to play in the treatment of paediatric solid tumours.

[High dose chemotherapy followed by autologous bone marrow graft in solid tumors in children: arguments for]

Arguments for the use of high-dose chemotherapy followed by autologous bone marrow transplantation in pediatric solid tumors are discussed. The dose effect relationship in pediatric oncology conventional chemotherapy is emphasized. Results of high-dose chemotherapy followed by autologous bone marrow transplantation are encouraging in metastatic neuroblastoma and Ewing's sarcoma. The probability of event free survival is increased of about 30% as compared to that of conventional treatments. This therapeutic approach could be of value in other pediatric solid tumors, particularly in some poor prognosis forms of Wilm's tumors. However, until now, the results remain preliminary. On the other hand, the role of this strategy in chemoresistant tumors, such as malignant gliomas, remains under investigation.

Prevention of gram-positive infections in patients treated with high-dose chemotherapy and bone marrow transplantation: a randomized controlled trial of vancomycin

Between January 1986 and June 1988, 155 patients (73 children and 82 adults), who were candidates for bone marrow transplantation, were included in a randomized controlled trial (75 patients in vancomycin group and 80 patients in the group without vancomycin) to evaluate the efficiency of a short course of vancomycin (10 mg/kg i.v. every 6 hours, day-5 to +1) in decreasing the incidence of Gram-positive infections during aplasia after high-dose chemotherapy and bone marrow transplantation. There was no statistical difference in the occurrence of documented septicemia, documented coccus Gram-positive infections, or fever of unknown origins during aplasia in the 2 groups. Thus, short prophylactic treatment with vancomycin proved inefficient in reducing morbidity due to infection after high-dose chemotherapy and bone marrow transplantation.

Comparison of auto versus allografting as consolidation of primary treatments in advanced neuroblastoma over one year of age at diagnosis: report from the European Group for Bone Marrow Transplantation

A case control study was performed to investigate the potential advantage of allogeneic bone marrow transplantation in advanced or poorly responding neuroblastoma first remission patients using the European BMT Solid Tumor Registry. Seventeen allogeneic and 34 autologous bone marrow transplantation (BMT) cases were matched based on a number of prognostic factors including age, sex, prior treatment duration, pre-graft response status and bone and BM involvement before BMT. Only single BMT procedures are included. The median age at diagnosis was 47 months (range 18-113 months). The median follow-up time since BMT is 58 months (range 13-133 months). The only significant prognostic factor within the allogeneic BMT (p = 0.012) and autologous BMT groups (p = 0.025) was residual skeletal disease before BMT, detected by mIBG in 86% of the cases. However, the progression-free survival was not significantly different: 35% and 41% at 2 years, respectively. Only half of the allogeneic BMT patients had developed graft-versus-host disease (GVHD): 7 of 9 grade I-II and only 2 of 9 grade IV. The median donor age was very young with 74 months (range 20-240 months) and 10 of 17 were sex matched. Thus absence of GVHD risk factors in young children could be the major obstacle in achieving an anti-tumor effect with allogeneic BMT in neuroblastoma.

[Humoral immunity and infections during bone marrow transplantation in children: study of 127 transplanted patients successively in a same center]

BACKGROUND

Children with malignant diseases are frequently given high dose chemotherapy plus autologous bone marrow transplants. Infectious complications can lead to morbidity and mortality in this type of treatment. This study was designed to determine whether immunoglobulin deficiency is an additional risk factor for infections.

PATIENTS AND METHODS

One hundred and twenty seven children with solid malignant tumors were treated between November 1987 and April 1992 in our Department by chemotherapy followed by autologous bone marrow transplantation. Their serum IgA, IgG and IgM concentrations were measured by nephelometry before chemotherapy, on the day of transplantation and every week thereafter. The frequency and severity of infectious episodes in all the children were recorded using a standard scale. The patients were divided into two subgroups, defined according to their serum IgG concentrations before the transplantation and 7 and 21 days later. RESULTS-Ig deficiency during transplantation was not associated with the occurrence of septicemia or focal infections. It was associated with the course of infection (P = 0.003) and with the occurrence of zoster virus infection during the first 6 months after transplantation (P = 0.003).

CONCLUSIONS

Immune replacement during bone marrow transplantation may be indicated in children at risk of Ig deficiency. Fifty percent of the children with solid tumors treated in our institution were at risk of this deficiency.

Refining interpretation of MIBG scans in children

In pediatrics, the distribution of radioiodinated metaiodobenzylguanidine (MIBG) has been studied primarily in neuroblastoma. However, normal patterns in children show a number of particularities and pitfalls related to the context of pediatric oncology which must be identified.

METHODS

We report on 28 equivocal scans in 24 children. In all cases, two experienced observers judged the scans to be equivocal and the definite interpretations were confirmed by follow-up.

RESULTS

Difficulties in interpreting the scans were observed at the level of the thorax (15 patients), the abdomen (5 patients), the head (4 patients) or elsewhere (4 patients). The final interpretation of the scans was attributed to an unusual physiological pattern linked to age (9 patients), tumoral context (17 patients) or artifacts (2 patients).

CONCLUSIONS

A number of important physiological areas of uptake in soft tissues can lead to false-positive interpretations of normal scans, such as the physiological upper thoracic uptake which has never been previously described. Numerous technical and physiological possibilities exist and those pitfalls must be ruled out. A precise knowledge of these technical difficulties and physiological variants can reduce the number of equivocal MIBG scans.

Antiinfective prophylaxis with ceftazidime and teicoplanin in children undergoing high-dose chemotherapy and bone marrow transplantation

Sixty children treated for solid tumors with high-dose chemotherapy followed by bone marrow transplantation were randomly assigned to one of two antibiotic protocols. Group A received prophylaxis consisting of ceftazidime plus teicoplanin beginning before the onset of aplasia and fever; group B received exactly the same antibiotic regimen but beginning at the onset of fever. The two groups were compared in terms of the rate of septicemia, fever of unknown origin, the time-lapse before the appearance of septicemia, the sensitivity of the causative organisms to the antibiotics, the effect of the latter on the intestinal flora, and the rate of fungal infections. The incidence of septicemia was significantly lower in group A (6.6%) than in group B (24.0%), mainly due to the prevention of episodes of early onset. Similarly, the appearance of the first episode of fever was delayed in group A, and the overall duration was reduced. Amphotericin B was prescribed empirically with the same rule in both groups, but three children in group A did not require amphotericin B. The effect on the intestinal flora was similar in the two groups; it must, however, be closely monitored so that the presence of potential pathogens can be dealt with appropriately.

What is the prognostic value of osteomedullary uptake on MIBG scan in neuroblastoma patients under one year of age?

Twenty-seven infants under one year of age with metastatic neuroblastoma were studied for osteomedullary metastases. They were evaluated by at least two imaging procedures: X-ray films and MIBG scan. Taking into account the results of these investigations, 3 groups were defined: osteomedullary metastases were detected in 8 infants by both X-ray and MIBG scan, no osteomedullary sites were detected by either technique in 13 patients, and 6 had osteomedullary foci with positive MIBG uptake but no radiological abnormality. These three groups were apparently different in terms of median age, response to chemotherapy, and long-term survival. The third group, which has not been previously described, appears to have a better prognosis than patients with radiologically detectable bone lesions. Nevertheless it was necessary to use intensive chemotherapy to obtain remission in these particular patients. It should be mandatory to specify the investigatory technique used to describe osteomedullary metastases in infants and treatment should be adapted according to this grouping system.

Negative 123-meta-iodobenzyl-guanidine imaging in Ewing's sarcoma of bone

The role of radiolabeled meta-iodobenzyl-guanidine (mIBG) is established in the detection and the staging of neuroblastoma. We designed a study of mIBG scanning for patients with Ewing's sarcoma, a tumor for which a neuroectodermic origin has been proposed. We explored 15 children with round cell sarcoma of bone by a whole body scan carried out 24 hours after injection of 123-I mIBG. No patient demonstrated significant uptake either at the site of the primary or at the sites of metastases. These results suggest that despite its neural histogenesis Ewing's sarcoma is a member of the nonneuroblastoma neural crest tumors, which does not produce or store adrenergic metabolites.

Autologous bone marrow transplantation for pediatric Wilms' tumor: the experience of the European Bone Marrow Transplantation Solid Tumor Registry

This survey includes 25 children with Wilms' tumor undergoing high-dose chemotherapy associated with autologous bone marrow transplantation (ABMT) in the period June 1984-December 1991 and enrolled in the European Bone Marrow Transplantation Registry for Solid Tumors. At diagnosis, 12 children presented stage IV disease, 5 stage III, 3 stage II, and 5 stage I. Before ABMT, 21 children had 1 to 4 relapses (median 1); 13 achieved a second or subsequent complete remission (CR), four stage IV children failed to respond to first line treatment and achieved either CR (3 patients), or partial remission (PR) after second line therapy. At high-dose chemotherapy, 17 children were in CR and 8 had measurable disease. Seven different high-dose regimens were administered, even if 20 children received melphalan mostly associated with vincristine and 8 involved field radiotherapy. Three children died early of pneumonitis; 2 developed an acute transient renal failure, 1 a chronic renal failure. Out of the 8 children with target disease at graft, 2 died of toxicity, 5 achieved CR, 1 obtained PR, and only 1 is presently alive in CCR at 39 months after ABMT. Of the 17 children grafted in CR, 8 are alive event-free at 14-90 months (median 34) from ABMT; 7 relapsed at 3-23 months (median 7 months); 1 died of toxicity and 1 was lost to follow-up in CR at 12 months. A salvage attempt with high-dose chemotherapy in children with resistant or poor prognosis recurrent Wilms' tumor seems to be justified. An international cooperative protocol taking into account the increased risk of lung and renal toxicity is necessary.

Impact of megatherapy on survival after relapse from stage 4 neuroblastoma in patients over 1 year of age at diagnosis: a report from the European Group for Bone Marrow Transplantation

PURPOSE

Relapse from stage 4 neuroblastoma usually carries a poor prognosis. A retrospective study using the European Bone Marrow Transplant (EBMT) Solid Tumor Registry was undertaken to define the role of megatherapy (MGT) in relapsed patients.

PATIENTS AND METHODS

After relapse, 33 boys and 15 girls with previous stage 4 neuroblastoma received intensification by MGT followed by either autologous (n = 42) or allogeneic (n = 6) bone marrow rescue in 11 European institutions. The median age at diagnosis was 47 months (range, 14 to 134) and the median interval from diagnosis to relapse was 16 months (range, 4 to 94). Thirty patients had received only conventional-dose primary treatments (group A), whereas 18 patients had previously received intensification with MGT (group B). The median follow-up time of the total group is 95 months (range, 25 to 185).

RESULTS

The actuarial overall survival rate at 2 years after MGT for relapse is 27% for group A and 0% for group B (P = .02). Three adverse, independent prognostic factors were confirmed by multivariate analysis using the Cox proportional hazards regression model: an interval of less than 12 months between diagnosis and relapse (P < .0001), nonresponding or untreated relapse (P = .0002), and previous MGT during primary treatments (P = .055). None of the other variables analyzed, such as sex, age, bone or bone marrow involvement at diagnosis or at relapse, and type of MGT at relapse, influenced outcome in this patient cohort.

CONCLUSION

Responding patients who relapse more than 12 months from diagnosis who had not received previous MGT appear to benefit from consolidation MGT. Relapse patients who do not fulfill these criteria gain no advantage from this cost-intensive procedure and should be treated differently.

[Neuroblastoma. Current clinical and therapeutic aspects. Contributions of modern biology]

Neuroblastoma is a malignant tumour of the sympathetic tissue observed in children, generally before 6 years and before 1 year in one-third of the cases. In most cases the primary tumour lies in the retroperitoneal region, and in particular in the adrenal gland. Metastases affect the bones and bone-marrow after the age of 1 year and the liver in infants. Children whose metastases are present at the time of diagnosis are the most numerous. The therapeutic problems posed by non-metastatic forms are almost exclusively due to the difficulties encountered in complete excision of the tumour. For this reason, tumour reduction by preoperative chemotherapy plays a large role in the therapeutic approach. The prognosis of metastatic forms is totally different in infants and in older children: in infants, hepatic metastases without bone lesions have a favourable prognosis as a rule and sometimes regress without treatment. In older children, the usual osteomedullary damage still has a very sombre prognosis despite the recent therapeutic advances due to high-dose chemotherapy with bone-marrow transplantation. Cytogenetic studies and molecular biology have improved our understanding of these differences in the outcome of the disease. Amplification of Nmy cellular oncogene, ploidy and chromosome 1 short-arm deletion are essential prognostic factors in this particular tumour.

Systemic Candida infection in pediatric BM autotransplantation: clinical signs, outcome and prognosis

Of the 393 children who underwent BM autotransplantation in the pediatric oncology unit of the Institut Gustave Roussy between February 1979 and September 1991, 14 (3.56%) developed disseminated Candida infection within 3 months. This incidence was far lower than in other published series. Eleven of the 14 patients recovered from the infection, giving a far higher survival rate (78%) than among adult BM transplant recipients (usually < 30%). All 14 patients had four or more risk factors and persistent BM aplasia (median, 25 days); six had Candida tropicalis infection. Four cases of deep visceral involvement were documented, two of which were lethal. Clinical signs were relatively uniform and included secondary high-grade fever (> 40 degrees C) for 8 days; half the patients developed cardiovascular impairment, respiratory distress, neurological disturbances (altered consciousness or delirium) and severe diarrhoea, within as little as 10 days after transplantation. Blood cultures rapidly became positive after the onset of clinical signs and this permitted prompt treatment with a combination of amphotericin B and 5-fluorocytosine; in addition, central catheters were removed. Blood cultures became sterile within 4 days of treatment in 10 of the 14 cases. The generally favourable outcome in this series could be related to the young age of the patients, the absence of GVHD, the absence of total body irradiation in the conditioning regimen, and early antifungal treatment.

Curability of relapsed childhood B-cell non-Hodgkin's lymphoma after intensive first line therapy: a report from the Société Française d'Oncologie Pédiatrique

The very high cure rate in advanced B-cell non-Hodgkin's lymphoma in children using intensive multiagent therapy has been previously reported by the French Sociéte Française d'Oncologie Pédiatrique lymphoma Malin B type (LMB) group. To address the issue of salvageability in an unselected group of patients who had all received the same front-line therapy, the outcome of relapses following the LMB 84 (216 patients) protocol have been reviewed. Fourteen percent of patients achieving complete remission (CR) relapsed, ie, 27 of 195. Relapse sites comprised the central nervous system (CNS) alone (6 cases), lung or mediastinum (2 cases), abdomen (8 cases), head and neck (2 cases), or multifocal (9 cases). There were three early deaths due to disease. Twenty-four patients received rescue chemotherapy regimens and 15 were treated with high-dose chemotherapy and bone marrow rescue (1 allogeneic). Of these, 9 were in second CR, 4 in second partial remission, and 2 treated during progressive disease. One died in CR from treatment-related toxicity. Ten relapsed postbone marrow transplant and 4 are alive disease free and probably cured. Two of the long-term survivors had some delay during initial chemotherapy due to toxicity and two were isolated CNS relapses. Twelve of 27 patients did not proceed to megatherapy (12 of 12 died).

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.

Localized dumbbell neuroblastoma: a study of 25 cases treated between 1982 and 1987 using the same protocol

Among the 108 non-metastatic neuroblastomas treated at the Institut Gustave Roussy between 1982 and 1987, 25 dumbbell neuroblastomas were observed. Therapeutics included: 1) an initial laminectomy in forms with neurological deficit; 2) surgical excision of the primary tumor; 3) preoperative chemotherapy in children in which the primary tumor was considered as unresectable at diagnosis and postoperative chemotherapy in cases of incomplete resection; and 4) radiation therapy on macroscopic residual disease. Fifteen out of 25 (60%) presented a neurological deficit. A laminectomy was performed in 14 cases. Neurological recovery was good in 4 cases, partial in 4 cases, and absent in 4 cases. Two patients were worse after the procedure. The event-free survival was 88%. This high survival rate is linked: 1) to the non-metastatic stage; 2) to a high proportion of children under 1 year of age (18/25) (median age = 7 months); and 3) to a high proportion of thoracic location (12/25). The high incidence of macroscopically incomplete excision (13/25) did not jeopardize the prognosis. Out of the 22 survivors, there were 8 cases of major neurological sequellae (36%) and 5 cases of major orthopedic ones (26%). The coexistence of a serious functional prognosis and an excellent vital prognosis for these patients has led us to analyse the therapeutic modalities, to reevaluate the necessity of routine initial neurosurgical removal by laminectomy and to discuss the use of first line chemotherapy.

Effect of human granulocyte colony stimulating factor on neuroblastoma cell growth

We have studied the effect of recombinant human granulocyte colony-stimulating factor (G-CSF) on the growth of three different human neuroblastoma (NB) cell lines, using a clonal cell culture and a short proliferation test. The results have shown a lack of effect of G-CSF on the three cell lines. These data promote the use, in clinical trials, of G-CSF as adjunctive treatment in children with NB receiving intensive chemotherapy.

Etoposide and carboplatin in neuroblastoma: a French Society of Pediatric Oncology phase II study

PURPOSE

A phase II study of etoposide (VP 16) and carboplatin (CBDCA) was performed in patients with metastatic neuroblastoma (NB). The aim of the study was to find an alternative treatment for induction with different toxicities than the VP 16/cisplatin (CDDP) combination.

PATIENTS AND METHODS

Forty-seven patients who were from 6 months to 16 years of age, with either relapsed (29) or primary resistant (18) NB, were included in a cooperative multicenter phase II study of the French Society of Pediatric Oncology (SFOP). The schedule consisted of 5 consecutive days of VP 16 100 mg/m2/d and CBDCA 160 mg/m2/d.

RESULTS

The response rate for the 39 assessable patients was 43%; there were four complete remissions and 13 partial remissions. Neither the status of the patients nor the total dose of CDDP that was received previously influenced response. Hematologic toxicity was marked and caused considerable delay between courses (median interval, 39 days). In these heavily pretreated patients, 16% had a more than 50% decrease in creatinine clearance and a 22% World Health Organization (WHO) grade 2 ototoxicity.

CONCLUSION

This VP 16/CBDCA combination deserves further evaluation for efficacy and toxicity in newly diagnosed patients, and the combination of both drugs should be considered for high-dose therapy with bone marrow transplantation.

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.

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.

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.