Marc Bierings

Autologous haemopoietic stem-cell transplantation in four patients with refractory juvenile chronic arthritis

BACKGROUND Autologous haemopoietic stem-cell transplantation (AHSCT) had been described as a possible treatment for severe autoimmune disease refractory to conventional treatment. We report the first four children with severe forms of juvenile chronic arthritis (JCA) treated with AHSCT. METHODS We studied three children with systemic JCA and one child with polyarticular JCA. Unprimed bone marrow was taken 1 month before AHSCT. T-cell depletion of the graft was done with CD2 and CD3 antibodies. We used a preparative regimen of antithymocyte globulin (20 mg/kg), cyclophosphamide (200 mg/kg) and low-dose total body irradiation (4 Gy). Methotrexate and cyclosporin were stopped before AHCST, prednisone was tapered after 2 months. FINDINGS Our patients showed a drug-free follow-up of 6-18 months with a marked decrease in joint swelling, pain, and morning stiffness. Erythrocyte sedimentation rate, C-reactive protein, and haemoglobin returned to almost normal values within 6 weeks. Despite T-cell depletion there was a rapid immune reconstitution in three out of four children. Two patients developed a limited varicella zoster virus eruption, which was treated by aciclovir. INTERPRETATION AHSCT for severe JCA was well tolerated and induced a remission of disease in four children with JCA that was resistant to conventional treatment. Prolonged prednisone-free growth catch-up and general well-being is a major therapeutic gain in such children. The actual follow-up is too short, however, for us to conclude that these children are completely cured of their disease.

Health care failure mode and effect analysis: a useful proactive risk analysis in a pediatric oncology ward

Background: Pediatric inpatient settings are known for their high medication error rate. The aim of this study was to investigate whether the Health Care Failure Mode and Effect Analysis (HFMEA) is a valid proactive method to evaluate circumscribed health care processes like prescription up to and including administration of chemotherapy (vincristine) in the pediatric oncology inpatient setting. Methods: A multidisciplinary team consisting of a team leader, pharmacy, nursing and medical staff and a patient’s parent was assembled in a pediatric oncology ward with a computerized physician order entry system. A flow diagram of the process was made and potential failure modes were identified and evaluated using a hazard scoring matrix. Using a decision tree, it was determined for which failure mode recommendations had to be made. Results: The process was divided into three main parts: prescription, processing by the pharmacy, and administration. Fourteen out of 61 failure modes were classified as high risk, 10 of which were sufficiently covered by current protocols. For the other four failure modes, five recommendations were made. Four additional recommendations were made concerning non-high risk failure modes. Most of them were implemented by the hospital management. The whole process took seven meetings and a total of 140 man-hours. Conclusions: The systematic approach of HFMEA by a multidisciplinary team is a useful method for detecting failure modes. A patient or a parent of a patient contributes to the multidisciplinarity of the team.

Whole-body MRI, including diffusion-weighted imaging, for the initial staging of malignant lymphoma: comparison to computed tomography.

Purpose:To assess the value of whole-body magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI), for the initial staging of malignant lymphoma, compared with computed tomography (CT). Materials and Methods:Thirty-one consecutive patients with newly diagnosed malignant lymphoma prospectively underwent whole-body MRI (T1-weighted and short inversion time inversion recovery [n = 31], and DWI [n = 28]) and CT. Ann Arbor stages were assigned by 1 radiologist according to whole-body MRI findings, and by another radiologist according to CT findings. Differences in staging between whole-body MRI (without and with DWI) and CT were resolved using other (imaging) studies (including 18F-fluoro-2-deoxyglucose positron emission tomography and bone marrow biopsy) and follow-up studies as reference standard. Results:Staging results of whole-body MRI without DWI were equal to those of CT in 74% (23/31), higher in 26% (8/31), and lower in 0% (0/31) of patients, with correct/incorrect/unresolved overstaging relative to CT in 3, 2, and 2 patients, respectively, and incorrect staging of both modalities in 1 patient. Staging results of whole-body MRI with DWI were equal to those of CT in 75% (21/28), higher in 25% (7/28), and lower in 0% (0/28) of patients, with correct/incorrect overstaging relative to CT in 6 and 1 patient(s), respectively. Conclusion:Our results suggest that initial staging of malignant lymphoma using whole-body MRI (without DWI and with DWI) equals staging using CT in the majority of patients, whereas whole-body MRI never understaged relative to CT. Furthermore, whole-body MRI mostly correctly overstaged relative to CT, with a possible advantage of using DWI.

Clinical significance of flowcytometric minimal residual disease detection in pediatric acute myeloid leukemia patients treated according to the DCOG ANLL97/MRC AML12 protocol.

Analysis of minimal residual disease (MRD) in childhood acute myeloid leukemia (AML) may predict for clinical outcome. MRD levels were assessed by flowcytometric immunophenotyping in 94 children with AML enrolled into a single trial (United Kingdom Medical Research Council AML12 and similar Dutch Childhood Oncology Group ANLL97). An aberrant immunophenotype could be detected in 94% of patients. MRD levels after the first course of chemotherapy predicted for clinical outcome: 3-year relapse-free survival was 85%±8% (s.e.) for MRD-negative patients (MRD<0.1%), 64%±10% for MRD-low-positive patients (0.1%⩽MRD<0.5%) and only 14±9% for MRD-high-positive patients (MRD⩾0.5%; P<0.001), whereas overall survival was 95%±5%, 70%±10% and 40%±13%, respectively, (P<0.001). Multivariate analysis allowing for age, karyotype, FLT3-internal tandem duplications and white blood cell count at diagnosis showed that MRD after the first course of chemotherapy was an independent prognostic factor. Although comparison of paired diagnosis-relapse samples (n=23) showed immunophenotypic shifts in 91% of cases, this did not hamper MRD analysis. In conclusion, flowcytometric MRD detection is possible in children with AML. The level of MRD after the first course of chemotherapy provides prognostic information that may be used to guide therapy.

Human herpes virus 6 plasma DNA positivity after hematopoietic stem cell transplantation in children: an important risk factor for clinical outcome.

Human herpes virus 6 (HHV6) is known to reactivate after hematopoietic stem cell transplantation (HSCT), and has been suggested to be associated with severe clinical manifestations in adults. The clinical significance in children remains unclear. We investigated the incidence of HHV6 reactivation in relation to HSCT-associated morbidity and mortality in children. Between January 2004 and May 2006, 58 pediatric patients, median age 7.6 years (range: 0.1-18.1 years), received their first allogeneic HSCT. After HSCT, HHV6, Epstein Barr Virus (EBV), cytomegalovirus (CMV), and adenovirus (AdV)-plasma loads were weekly measured by quantitative PCR. Clinical features, engraftment, graft-versus-host disease (GVHD), and HSCT-associated mortality and morbidity were monitored. HHV6 reactivations were classified in group I (no reactivation), group II (loads <1000 cp/mL) and group III (loads >1000 cp/mL). CMV, EBV, Herpes Simpex Virus, Varicella Zoster Virus, and AdV-reactivations were treated according to local guidelines. HHV6 was treated only when there was clinical suspicion of disease. Thirty-six HLA-identical and 22 HLA nonidentical grafts were transplanted of which 43 were bone marrow or peripheral blood stem cells grafts and 15 were cord blood (CB) grafts. Median follow-up of the patients was 15.5 (1-35) months. HHV6 reactivation occurred in 39 of 58 (67%) patients with 31 of 39 (80%) occurring within the first 30 days post-HSCT. In 26 of 58 (45%) patients (group III), HHV 6 reactivation was significantly associated with higher nonrelapse mortality (P = .02), using multivariate Cox proportional hazard models and grade 2-4 acute GVHD (P = .03) and chronic GVHD (P = .05) in a multivariate logistic regression analysis. HHV6 reactivation is very common after HSCT in children and is associated with serious transplantation-related morbidity and mortality. Although the exact role of HHV6 reactivation after HSCT has to be elucidated, early detection and initiation of therapy might be of benefit.

A review on allogeneic stem cell transplantation for newly diagnosed pediatric acute myeloid leukemia

Survival of pediatric acute myeloid leukemia (AML) has improved considerably over the past decades. Since 1985, allogeneic stem cell transplantation (allo-SCT) is widely recommended for patients who have a matched sibling donor. However, it remains controversial whether allo-SCT is superior to chemotherapy for children with newly diagnosed AML. This review summarizes phase 3 clinical trials that compared allo-SCT with chemotherapy (including autologous SCT) in pediatric AML, excluding studies that did not use the intention-to-treat analysis or correct for time-to-transplantation. Although allo-SCT might prevent more relapses than chemotherapy, the number needed for transplantation (with allo-SCT) to prevent one relapse is in the order of 10 patients. Moreover, overall survival is similar with both methods in most recent studies, apparently because of increased salvagability of a relapse when initial therapy concerned chemotherapy only, and because of a higher treatment-related mortality with allo-SCT. Because allo-SCT also gives more severe side effects and results more often in secondary malignancies than chemotherapy, we do not recommend allo-SCT in first remission for pediatric AML in general. Further research should focus on the possibility that subgroups might benefit from allo-SCT, aiming at further improvements in the prognosis of pediatric AML.

Long-term results of Dutch Childhood Oncology Group studies for children with acute lymphoblastic leukemia from 1984 to 2004

The Dutch Childhood Oncology Group (DCOG) has used two treatment strategies for children with acute lymphoblastic leukemia (ALL) based on Pinkels St Jude Total Therapy or the Berlin–Frankfurt–Münster (BFM) backbone. In four successive protocols, 1734 children were treated. Studies ALL-6 and ALL-9 followed the Total Therapy approach; cranial irradiation was replaced by medium-dose methotrexate infusions and prolonged triple intrathecal therapy; dexamethasone was used instead of prednisone. Studies ALL-7 and ALL-8 had a BFM backbone, including more intensive remission induction, early reinduction and maintenance therapy without vincristine and prednisone pulses. The 5-year event-free survival and overall survival increased from 65.4 to 80.6% (P<0.001) and from 78.7 to 86.4% (P=0.07) in ALL-7 and ALL-9, respectively. In ALL-7 and ALL-8 National Cancer Institute (NCI) high-risk criteria, male gender, T-lineage ALL and high white blood cells (WBCs) predict poor outcome. In ALL-9 NCI criteria, gender, WBC >100 × 109/l, and T-lineage ALL have prognostic impact. We conclude that the chemotherapy-only approach in children with ALL in Total Therapy-based strategies and BFM-backbone treatment does not jeopardize survival and preserves cognitive functioning. This experience is implemented in the current DCOG-ALL-10 study using a BFM backbone and minimal residual disease-based stratification.

Association between Busulfan Exposure and Outcome in Children Receiving Intravenous Busulfan before Hematologic Stem Cell Transplantation

Busulfan, combined with therapeutic drug monitoring-guided dosing, is associated with higher event-free survival (EFS) rates due to fewer graft failures/relapses and lower toxicity. The optimal target area under the curve (AUC) and dosing schedule of intravenous busulfan in children undergoing hematopoietic stem cell transplantation (HSCT) remain unclear, however. We conducted a retrospective analysis of the association between busulfan exposure and clinical outcome in 102 children age 0.2 to 21 years who received busulfan 1 or 4 times daily before undergoing HSCT (46 malignant and 56 nonmalignant indications). EFS and overall survival after a median of 2 years of follow-up were 68% and 72%, respectively. EFS was optimal when the exposure of busulfan (AUC) was 78 mg x h/L (95% confidence interval=74 to 82 mg x h/L). Acute graft-versus-host disease (aGVHD) grade II-IV occurred more frequently with greater busulfan exposure. The addition of melphalan was an independent risk factor; melphalan use combined with high busulfan exposure (AUC >74 mg x h/L) was associated with high incidences of aGVHD (58%), veno-occlusive disease (66%), and mucositis grade III-IV (26%). Dosing frequency (1 or 4 times daily) was not related to any outcome. In conclusion, dose targeting of busulfan to a narrow therapeutic range was found to increase EFS in children. Adding melphalan to optimal busulfan exposure is associated with a high incidence of toxicity.

Body Weight-Dependent Pharmacokinetics of Busulfan in Paediatric Haematopoietic Stem Cell Transplantation Patients: Towards Individualized Dosing

AbstractBackground and Objectives: The wide variability in pharmacokinetics of busulfan in children is one factor influencing outcomes such as toxicity and event-free survival. A meta-analysis was conducted to describe the pharmacokinetics of busulfan in patients from 0.1 to 26 years of age, elucidate patient characteristics that explain the variability in exposure between patients and optimize dosing accordingly. Patients and Methods: Data were collected from 245 consecutive patients (from 3 to 100 kg) who underwent haematopoietic stem cell transplantation (HSCT) in four participating centres. The inter-patient, inter-occasion and residual variability in the pharmacokinetics of busulfan were estimated with a population analysis using the nonlinear mixed-effects modelling software NONMEM VI. Covariates were selected on the basis of their known or theoretical relationships with busulfan pharmacokinetics and were plotted independently against the individual pharmacokinetic parameters and the weighted residuals of the model without covariates to visualize relations. Potential covariates were formally tested in the model. Results: In a two-compartment model, body weight was the most predictive covariate for clearance, volume of distribution and inter-compartmental clearance and explained 65%, 75% and 40% of the observed variability, respectively. The relationship between body weight and clearance was characterized best using an allometric equation with a scaling exponent that changed with body weight from 1.2 in neonates to 0.55 in young adults. This implies that an increase in body weight in neonates results in a larger increase in busulfan clearance than an increase in body weight in older children or adults. Clearance on the first day was 12% higher than that of subsequent days (p < 0.001). Inter-occasion variability on clearance was 15% between the 4 days. Based on the final pharmacokinetic-model, an individualized dosing nomogram was developed. Conclusions: The model-based individual dosing nomogram is expected to result in predictive busulfan exposures in patients ranging between 3 and 65 kg and thereby to a safer and more effective conditioning regimen for HSCT in children.

Association between anti-thymocyte globulin exposure and CD4+ immune reconstitution in paediatric haemopoietic cell transplantation: a multicentre, retrospective pharmacodynamic cohort analysis

BACKGROUND Anti-thymocyte globulin (ATG) was introduced into the conditioning regimen in haemopoietic cell transplantation (HCT) to prevent graft-versus-host-disease (GvHD) and graft failure. However, ATG can also cause delayed immune reconstitution of donor T cells. We studied the relation between exposure to active ATG and clinical outcomes in children. METHODS In this retrospective analysis, all patients (age 0·2-23 years) receiving their first HCT between April 1, 2004, and April 1, 2012, who received ATG (thymoglobulin) in two Dutch paediatric HCT programmes were included. The cumulative dose of ATG was chosen according to local protocols and was given intravenously over 4 days consecutively. ATG exposure measures (maximum concentration, concentration at time of HCT, clearance, days to reach a concentration below the lympholytic concentration of one arbitrary unit [AU] per mL, total area under the curve [AUC], AUC before HCT, and AUC after HCT) were calculated using a validated population pharmacokinetic model. The main outcome of interest was immune reconstitution (defined as CD4+ T cells >0·05 × 10(9) cells per L in two consecutive measurements within 100 days). Other outcomes of interest were survival, acute and chronic GvHD, and graft failure. We used Cox proportional hazard models, logistic regression models, and Fine-Gray competing risk regressions for analyses. FINDINGS 251 patients were included. The chance of successful immune reconstitution decreased as the ATG AUC after HCT increased (odds ratio 0·991, 95% CI 0·987-0·996; p<0·0001). Within the cord blood group, we noted decreased immune reconstitution above the lowest AUC quartile (≥ 20 AU × day/mL; p=0·0024), whereas in the bone marrow or peripheral blood stem cell group, decreased immune reconstitution was noted only in the highest quartile (≥ 100 AU × day/mL; p=0·0024). Successful immune reconstitution by day 100 was associated with increased overall survival (hazard ratio [HR] 0·49, 95% CI 0·29-0·81; p=0·0047) caused by reduced non-relapse mortality (0·40, 0·21-0·77; p=0·0062), and relapse-related mortality in myeloid leukaemia (0·25, 0·08-0·76; p=0·015). An AUC before transplantation of at least 40 AU × day/mL resulted in a lower incidence of acute GvHD (grade 2-4 HR 0·979, 95% CI 0·963-0·994; p=0·0081; and grade 3-4 0·975, 0·952-0·998; p=0·033), chronic GvHD (0·983, 0·968-0·998; p=0·029), and graft failure (0·981, 0·965-0·997; p=0·020) compared with an AUC of less than 40 AU × day/mL. INTERPRETATION These results stress the importance of improving the efficacy and safety of ATG in HCT by amending dosage and timing. Individualised dosing and timing of ATG to aim for optimum exposure before and after HCT could result in improved outcomes after paediatric HCT. FUNDING Dutch Organization for Scientific Research.