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Background: The application of population pharmacokinetic models and Bayesian methods offers the potential to develop individualized therapeutic approaches.Objectives: The current study presents an external evaluation of a vancomycin pharmacokinetic model in a pediatric cancer population and proposes an easy-to-use chart for clinicians for a priori vancomycin schedule adaptation to achieve target concentration.Methods: External evaluation of a population pharmacokinetic model of vancomycin administered via continuous infusion was realized in a new retrospective dataset of pediatric patients with cancer. The published population pharmacokinetic model was implemented in NONMEM 7.3 with the structural and variance parameter values set equal to estimates previously reported. Predictive performance was assessed by quantifying bias and accuracy of model prediction. Normalized prediction distribution errors were also evaluated. Dosage simulations were performed according to the target concentration.Results: A total of 77 patients were included in this study, representing 146 vancomycin courses and 289 concentrations. The model adequately predicted vancomycin concentrations (median prediction error % of − 9.4%, median |PE|% of 24.1%). Based on simulation results, vancomycin dosage (mg/kg) should be adapted for each child on the basis of body weight and cyclosporine coadministration.Conclusion: The model previously proposed by Guilhaumou et al. in pediatric patients with solid or hematological malignant disease was externally validated. Simulations have enabled the description of new dosage schedules and creation of a chart to help clinicians adapt vancomycin dosage. [ABSTRACT FROM AUTHOR]

The purpose of this multicenter study was to compare the long-term impact of a preparative regimen with either BUBU or TBI on health status and quality of life (QoL) in childhood acute leukemia survivors treated with hematopoietic SCT (HSCT). Two-hundred and forty patients were included. Sixty-six had received BU, while 174 had received TBI. Median follow-up from HSCT was 10.1 years. Multivariate analyses were performed to assess the occurrence of late effects according to treatment. QoL was assessed in 130 adults using SF-36 questionnaires. Patients developed fewer late complications after BU (2.35 vs 3.01, P=0.03) while the risk to present with at least one complication was equivalent in both groups (87.9% after BU and 93.1% after TBI, P=0.66). Detailed multivariate analyses revealed a lower risk of height growth failure (OR=0.2), cataract (OR=0.1) and iron overload (OR=0.2) after BU, and an increased risk of overweight (OR=3.9) and alopecia (OR=11.2). SF-36 mental and physical composite scores were similar in both treatment groups and proved significantly lower than French norms. Late effects induced by BU might differ from those experienced after TBI. Although less frequent, they are still of considerable importance and may affect patients' QoL. [ABSTRACT FROM AUTHOR]

Allogeneic hematopoietic SCT (HSCT) appears to be an efficient tool to cure high-risk AML in first CR but the choice between BU-based or TBI-based conditioning regimens still remains controversial. In order to analyze the impact of conditioning regimen on long-term survival, we conducted a retrospective analysis from French registry data including all consecutive patients under 18 years old (n=226) from 1980 to 2004 transplanted for AML in CR1 from sibling (n=142) or matched unrelated donors and given either TBI-1200 cGy and CY 120 mg/kg (TBI-Cy, n=84) or BU 16 mg/kg and CY 200 mg/kg (BuCy200, n=142). Patient subgroups were comparable for all criteria except for median age at diagnosis and HSCT and for donor type. Both 5-year OS and disease-free survival (DFS) were significantly better in BuCy200 group (P=0.02 and 0.005, respectively). In multivariate analysis, both HLA matching and BuCy200 appeared as good prognostic factors for treatment-related mortality and DFS. Grade 2-4 acute GvHD and chronic GvHD rates were statistically higher in TBI-Cy group than in Bu-Cy200 one with a RR at 2 (P=0.002). In total, Bu-Cy200 conditioning regimen gives better outcome compared with TBI-Cy irrespective of the stem cell source and the donor type. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented that discusses loss of heterozygosity in hematopoietic cells with a germline mutation of casitas B-lineage (CBL.

Despite progress in diagnosis and treatment, invasive aspergillosis (IA) remains a principal cause of mortality due to infection after allogeneic hematopoietic stem cell transplantation (AHSCT). In order to clarify the course of IA among children receiving an AHSCT before the advent of new drugs such as voriconazole or caspofungin, we retrospectively reviewed the medical records of all proven and probable IA between January 1986 and December 2000. 1) Ten children developed IA after AHSCT, mostly long after transplantation. Overall incidence was 2.7%. Seven of those children experienced 1 or more complications after AHSCT and before IA. Mortality was 90% with a median survival of 23 days (2–90). 2) Five children underwent AHSCT after a previous episode of IA. All patients were treated with systemic antifungal therapy combined with surgery. Median time between IA and AHSCT was 110 days (73–370). Two children were diagnosed with IA relapse after transplantation. One child was cured while the other died of IA and AHSCT complications. AHSCT could be considered even in the setting of previous IA, but established strategies implementing newer less toxic antifungal agents as treatment or prophylaxis in high-risk patients are needed. [ABSTRACT FROM AUTHOR]

Oral busulfan clearance is age-dependent and children experience a wide variability in plasma exposure. BSA- or age-based dosing is used with therapeutic drug monitoring (TDM) to reduce this variability. A new intravenous (IV) dosing of busulfan (Bu) based on body weight, designed to improve AUC targeting without TDM and dose-adjustment, was prospectively evaluated. Bu was administered as a 2 h IV infusion every 6 h over 4 days (16 administrations). Five dose levels were defined on body weight as follows: 1.0 mg/kg for <9 kg; 1.2 mg/kg for 9 to <16 kg; 1.1 mg/kg for 16–23 kg; 0.95 mg/kg for >23–34 kg; 0.80 mg/kg for >34 kg. Bu treatment was followed by Cyclophosphamide or Melphalan prior to allogeneic or autologous transplantation in 55 children aged 0.3–17.2 years (median 5.6 years). No difference in AUC values was observed between weight strata (mean ± SD 1248 ± 205 μmol·min), whereas a significant difference in Bu clearance was demonstrated. This new dosing enabled to achieve a mean exposure comparable to that in adults. At dose 1, 91% of patients achieved the targeted AUC range (900–1500 μmol·min) while no patients were underexposed. At doses 9 and 13, over 75% of patients remained within that target whilst most of the others were slightly above. Successful engraftment was achieved in all patients. In conclusion, from infants to adults this new dosing enabled, without TDM and dose adjustment, to successfully target a therapeutic AUC window. [ABSTRACT FROM AUTHOR]

Oral busulfan clearance is age-dependent and children experience a wide variability in plasma exposure. BSA- or age-based dosing is used with therapeutic drug monitoring (TDM) to reduce this variability. A new intravenous (IV) dosing of busulfan (Bu) based on body weight, designed to improve AUC targeting without TDM and dose-adjustment, was prospectively evaluated. Bu was administered as a 2 h IV infusion every 6 h over 4 days (16 administrations). Five dose levels were defined on body weight as follows: 1.0 mg/kg for <9 kg; 1.2 mg/kg for 9 to <16 kg; 1.1 mg/kg for 16–23 kg; 0.95 mg/kg for >23–34 kg; 0.80 mg/kg for >34 kg. Bu treatment was followed by Cyclophosphamide or Melphalan prior to allogeneic or autologous transplantation in 55 children aged 0.3–17.2 years (median 5.6 years). No difference in AUC values was observed between weight strata (mean ± SD 1248 ± 205 μmol·min), whereas a significant difference in Bu clearance was demonstrated. This new dosing enabled to achieve a mean exposure comparable to that in adults. At dose 1, 91% of patients achieved the targeted AUC range (900–1500 μmol·min) while no patients were underexposed. At doses 9 and 13, over 75% of patients remained within that target whilst most of the others were slightly above. Successful engraftment was achieved in all patients. In conclusion, from infants to adults this new dosing enabled, without TDM and dose adjustment, to successfully target a therapeutic AUC window. [ABSTRACT FROM AUTHOR]

This prospective study focused on risk factors and clinical outcome of pulmonary and cardiac late effects after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We prospectively evaluated 162 children by pulmonary function tests (PFTs) and cardiac shortening fraction (SF) before allo-HSCT and yearly up to the 5th year of follow-up. The 5-year cumulative incidence of lung and cardiac impairment was 35 (hazard rate=0.03) and 26% (hazard rate=0.06), respectively. Patients presenting abnormal PFTs and SF at last follow-up were 19 and 13%, respectively, with a median Lansky performance status of 90% (70–100). Chronic graft-versus-host disease (c-GVHD) was the major risk factor for reduced lung function in univariate (P=0.02) and multivariate analysis (P=0.02). Total body irradiation (TBI) alone and TBI together with pre-transplant anthracycline administration were significant risk factors for reduced cardiac function in univariate analysis, only (P=0.04 and 0.004, respectively). In conclusion, our prospective study demonstrates an asymptomatic post-allo-HSCT deterioration of pulmonary and cardiac function in some long-term survivors, who had been transplanted in childhood, and thus emphasizes the need for lifelong cardiopulmonary monitoring and the development of new strategies both to reduce pre-transplant cardiotoxic regimens and to treat more efficiently c-GVHD.Bone Marrow Transplantation (2007) 39, 667–675. doi:10.1038/sj.bmt.1705652; published online 2 April 2007 [ABSTRACT FROM AUTHOR]

Genetic determinants taking part in the development of systemic lupus erythematosus (SLE) are complex and not fully characterized. Dysregulated expression of genes involved in the control of apoptosis has been previously suggested. We report here a consanguineous family with SLE manifestations in three siblings associated in one of them with severe lymphoproliferative features. Laboratory studies showed no defect in CD95-mediated cell death. Screening expression of Bcl-2 family genes that regulate mitochondrial apoptosis pathway showed an overexpression of the antiapoptotic Bfl-1 gene. Real time RT-PCR analysis indicated that overexpression of Bfl-1 was restricted to B-cells, with normal expression in T-cells. Those results suggest that overexpression of Bfl-1 could result in impaired B-lymphocyte homeostasis and inappropriate immune response leading to autoimmune manifestations. [ABSTRACT FROM AUTHOR]

Summary:The purpose of this study was to identify risk factors for hypothyroidism after bone marrow transplantation (BMT) for high-risk or relapsed acute lymphoblastic leukaemia (ALL) in children. In all, 388 children with acute lymphoblastic leukaemia underwent allogeneic bone marrow transplantation between 1984 and 1994. Overall 5-year survival was 54.6%. Thyroid function was assessed in the 153 patients with more than 5 years of follow-up. In total, 16 patients developed uncompensated hypothyroidism (UH) and 46 compensated hypothyroidism (CH) a median of 2.9 and 2.7 years, respectively, after BMT. Thyroid dysfunction-free survival rates were 73.2%after 5 years and 59.2%after 10 years. Three factors were significantly associated with the onset of hypothyroidism, namely age, bone marrow transplantation in second remission, and single-dose total body irradiation (TBI). Ultrasonography of the thyroid showed nodules in 10 of 35 patients. The median time from BMT to nodule detection was 7.8 years. Cytology (n=5) and surgery (n=4) showed no evidence of thyroid cancer. Four of the 14 patients who received cytoreduction without TBI but with busulphan and cyclophosphamide developed UH (n=2) or CH (n=2). We concluded that children who undergo BMT for ALL are at a high risk of subsequent thyroid dysfunction.Bone Marrow Transplantation (2005) 35, 991-995. doi:10.1038/sj.bmt.1704945 Published online 4 April 2005 [ABSTRACT FROM AUTHOR]

Summary:Between September 1986 and June 1997, 24 children with high-risk ALL in CR1 were allografted after TAM (fractionated TBI, high-dose Ara-C, and melphalan; n=10) or BAM protocol (busulfan, high-dose Ara-C, and melphalan; n=14). The EFS for transplants from sibling donors was 33%with TAM and 62%with BAM (P=0.148). The probability of acute GvHD was 70%with TAM and 15%with BAM (P=0.003). Four of 17 evaluable patients relapsed: one after TAM and three after BAM. In all, 46 other children transplanted in CR beyond CR1 were studied for sequelae. Long-term side effects were more frequent in TAM vs BAM. In children with ALL, busulfan may be a good alternative to TBI to improve the quality of life.Bone Marrow Transplantation (2004) 34, 667-673. doi:10.1038/sj.bmt.1704605 Published online 6 September 2004 [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSC) fail to induce allogeneic responses in mixed lymphocyte reaction assays. Because MSC express HLA class I molecules, here we investaged whether they could be recognized as allogeneic targets by cytolytic T lymphocytes (CTL). With this aim, CTL precursor (CTLp) frequencies were measured following stimulation of T cells with either allogeneic mononuclear cells (MNC) or MSC originated from the same human bone marrow donor. Lysis of MSC was measured at day 10 of culture in standard chromium release assays. In addition, allogeneic PHA blast T cells or B‐EBV lymphoblastoid cell lines (LCLs) generated from the same donor were used as positive controls of lysis. Our results showed that when allogeneic MNC were used to stimulate T cells, a high CTLp frequency was detected towards MSC targets. However, when MSC were used as stimulators, CTLp frequencies were markedly altered whatever the targets used, i.e.: MSC, PHA blast T cells or EBV‐B LCLs. Moreover, when graded concentrations of MSC were added together with MNC upon stimulation of alloreactive T cells, we observed a dose‐dependent decrease in CTLp frequencies towards MSC targets. This inhibition of MSC lysis was partially overcomed by adding exogenous rh‐IL‐2 from the beginning of cultures. In addition, this suppressive effect was totally reproduced when, instead of MSC, supernatant harvested from MSC cultures was added to allogeneic MNC, upon stimulation of alloreactive T cells. In conclusion, our results demonstrate that MSC which can be recognized as targets by pre‐activated alloreactive CTLs, may be able to suppress differentiation of CTL precursors into CTL effectors through secretion of suppressive factors. [ABSTRACT FROM AUTHOR]

Summary:The aim of this study was to identify the risk factors for acute graft-versus-host disease (aGVHD) in children transplanted from a matched-sibling donor (MSD) or an unrelated donor (UD). In all, 87 children consecutively underwent allogeneic bone marrow transplantation (BMT) from MSD (n=36), and UD (n=51). GVHD prophylaxis included CsA alone (n=33) or with MTX (n=51). ATG was added in UD-BMT and thalassemic recipients. CsA whole-blood concentrations were measured by EMIT and the dosing regimen was monitored by Bayesian pharmacokinetic modelling. Trough blood concentration (TBC) during the first 2 weeks post transplantation was lower in children who developed grade II-IV aGVHD than those developing no GVHD or only grade I (57±9 vs 94±8?ng/ml, P=0.007), whereas peak blood concentration and area under concentration curve vs time were similar in both groups. TBC <85?ng/ml and ‘use of MTX’ were associated with aGVHD in MSD-SCT (P=0.003 and 0.007, respectively) as well as in UD-SCT (P=0.006 and 0.003). Donor age ?8 years was significant only in MSD-BMT. Our results have shown the significant decisive role of pharmacological factors such as CSA TBC or use of MTX in the occurrence of GVHD in MSD as well as in UD paediatric BMT.Bone Marrow Transplantation (2003) 32, 881-887. doi:10.1038/sj.bmt.1704239 [ABSTRACT FROM AUTHOR]

Summary:In order to determine optimal CsA trough blood concentrations (TBC) in the early post transplantation period, we analysed relationships between TBC and acute graft-versus-host disease (aGVHD) in paediatric SCT. A total of 94 children consecutively underwent allogeneic stem cell transplantation (SCT) from: matched-sibling (MSD) (n=36), mismatched-related (MMRD) (n=3) and unrelated donors (UD) (n=55). GVHD prophylaxis usually included CsA alone or with methotrexate. Antithymocyte globulin was added in UD-SCT. TBC during the first weeks of post transplantation were estimated retrospectively by a Bayesian pharmacokinetic method and statistically associated with aGVHD. In MSD-SCT, the mean TBC during the first 2 weeks post transplantation were 42±10 and 90±7?ng/ml, respectively, in patients with grade II-IV and 0-I aGVHD (P=0.001). In SCT from UD and MMRD, TBC were 73±4 vs 95±8?ng/ml (P=0.284). For TBC >85?ng/ml, no patient developed grade II-IV aGVHD, 10 developed mild aGVHD and 30 had no aGVHD. For TBC <65?ng/ml, 7/11 patients receiving an MSD-SCT and 4/18 receiving an UD- or MMRD-SCT developed grade II-IV aGVHD. The mean TBC corresponding to each grade were: no GVHD: 101±10?ng/ml, mild: 77±11?ng/ml, moderate: 61±13?ng/ml, severe: 56±15?ng/ml (P<0.001). These results reveal a strong relationship between TBC during the early post transplantation period and the severity of aGVHD in paediatric SCT.Bone Marrow Transplantation (2003) 32, 777-784. doi:10.1038/sj.bmt.1704213 [ABSTRACT FROM AUTHOR]

Summary:Over the last 15 years, we have performed a total of 30 haematopoietic stem cell transplants on 27 children suffering from Hurler's syndrome. These children were of median age 11 months at the time of diagnosis and 25 months at the time of transplantation. The phenotype was severe in 21 cases (78%). The donor was familial in 13 cases: nine genotypically identical, one phenotypically identical father and three HLA-mismatched donors. Unrelated donors were selected in 17 cases: four phenotypically identical and 13 with 1-4 HLA mismatches. The conditioning regimen generally consisted of busulphan 600?mg/m2 plus cyclophosphamide (Endoxan®) 260?mg/kg and cyclosporin with methotrexate for GvHD prophylaxis. Rabbit anti-thymocyte globulin (Thymoglobuline®) was given for all unrelated or familial mismatched transplantations. The median nucleated cell dose infused was 6.00 x 108 TNC/kg. No bone marrow (apart from one) was T cell depleted. For first transplants, engraftment was observed in 23/27 patients (pts) (85%). Primary graft failure was observed in 4/27 patients (16%), two were retransplanted from an unrelated donor, one with success. Four patients have died. The primary cause of death was infection in three cases (TRM : 11%) and disease progression in one case, after primary graft failure. Of the 23 living patients, two have disease progression after graft failure and 21 (78%) have functional grafts with a favourable long-term outcome after a median follow-up of 4.7 years, having either full or mixed chimaerism. Among surviving patients with functional grafts, 13 (62%) were transplanted from unrelated donors of whom 10 (77 %) had HLA disparities. There was a remarkably low incidence of GvHD. In our experience, haematopoietic stem cell transplantation using an HLA-matched familial donor or an HLA-matched or -mismatched unrelated donor without T cell depletion or irradiation can achieve a favourable outcome... [ABSTRACT FROM AUTHOR]

In order to control busulfan pharmacokinetic variability and toxicity, a specific monitoring protocol was instituted in our bone marrow transplant BMT paediatric patients including a test dose, daily Bayesian forecasting of busulfan plasma levels, and Bayesian individualization of busulfan dosage regimens. Twenty-nine children received BMT after a busulfan-based conditioning regimen. Individual pharmacokinetic parameters were obtained following a 0.5 mg*kg test dose and were used for daily individualization of dosage regimens during the subsequent 4-day course of treatment. Doses were adjusted to reach a target mean AUC per 6 h between 4 and 6 μg.h.ml+1. Plasma busulfan assays were performed by liquid chromatography. Pharmacokinetic analysis used the USC*PACK software. The performance of the test dose to predict AUC during the busulfan regimen was evaluated. Incidence of toxicity, chimerism and relapse, overall Kaplan–Meier survival, and VOD-free survival were compared after matching our patients (group A) with patients conditioned by using standard doses of busulfan (group B). Busulfan doses were decreased in 69% of patients compared to conventional doses. Expected AUC was significantly correlated with observed AUC and predictability of the test dose was 101.9 ± 17.9%. Incidence of VOD in group A was 3.4% vs 24.1% in group B, while the incidence of stomatitis was similar. Engraftment was successful in all patients in group A. The rate of full engraftment at 3 months post-BMT was higher in group A (P = 0.012). Long-term overall survival did not differ between the two groups, in contrast to the 90-day survival. VOD-free survival was higher in group A (P = 0.026). Pharmacokinetic monitoring and individualization of busulfan dosage regimen are useful in improving clinical outcome and reducing early mortality in paediatric bone marrow transplant recipients. Bone Marrow Transplantation (2001) 28, 743–751. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article regarding a successful treatment of Evans syndrome post-liver transplant with splenectomy and switch from tacrolimus to cyclosporine.

Pemphigus foliaceus is a skin disease in which antibodies against the cell surface of keratinocytes destroy the adhesion between epidermal cells, thereby producing blisters. It is a rare disease in childhood, and treatment guidelines for juvenile pemphigus foliaceus are lacking. An 8 year old boy with pemphigus foliaceus is described. He did not respond to topical steroids, and the condition flared up when high dose oral steroids were tapered. The lesions resolved completely in four weeks on dapsone, which was maintained for nine months with no major adverse effects, except for a moderate increase of the methaemoglobin concentration at the outset of treatment. There has been no evidence of disease reactivation in more than nine months of follow up since dapsone withdrawal. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Human herpes virus-6 encephalitis in a paediatric bone marrow recipient: successful treatment with pharmacokinetic monitoring and high doses of ganciclovir."

Unlabelled: We present the case of a breast-fed 5-month-old infant who presented with pancytopenia, secondary to intense myelofibrosis during the winter months because of undiagnosed rickets. The patient responded to oral vitamin D with rapid resolution of symptoms. Secondary hyperparathyroidism was the probable cause of the myelofibrosis.Conclusion: Although nutritional rickets remains a problem in developing countries, children in northern climates in industrialized countries may also be at risk. Rickets must be considered when assessing myelofibrosis in a very young child. [ABSTRACT FROM AUTHOR]

Background CBL missense mutations have recently been associated with juvenile myelomonocytic leukaemia (JMML), an aggressive myeloproliferative and myelodysplastic neoplasm of early childhood characterised by excessive macrophage/monocyte proliferation. CBL, an E3 ubiquitin ligase and a multi-adaptor protein, controls proliferative signalling networks by downregulating the growth factor receptor signalling cascades in various cell types. Methods and results CBL mutations were screened in 65 patients with JMML. A homozygous mutation of CBL was found in leukaemic cells of 4/65 (6%) patients. In all cases, copy neutral loss of heterozygosity of the 11q23 chromosomal region, encompassing the CBL locus, was demonstrated. Three of these four patients displayed additional features suggestive of an underlying developmental condition. A heterozygous germline CBL p.Y371H substitution was found in each of them and was inherited from the father in one patient. The germline mutation represents the first hit, with somatic loss of heterozygosity being the second hit positively selected in JMML cells. The three patients display a variable combination of dysmorphic features, hyperpigmented skin lesions and microcephaly that enable a 'CBL syndrome' to be tentatively delineated. Learning difficulties and postnatal growth retardation may be part of the phenotype. Conclusion A report of germline mutations of CBL in three patients with JMML is presented here, confirming the existence of an unreported inheritable condition associated with a predisposition to JMML. [ABSTRACT FROM AUTHOR]