-
1.
ESTRO ACROP and SIOPE recommendations for myeloablative total body irradiation in children
Hoeben, B. A. W., Pazos, M., Seravalli, E., Bosman, M. E., Losert, C., Albert, M. H., Boterberg, T., Ospovat, I., Mico Milla, S., Abakay, C. D., et al
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 2022
Abstract
BACKGROUND AND PURPOSE Myeloablative total body irradiation (TBI) is an important modality in conditioning for allogeneic hematopoietic stem cell transplantation (HSCT), especially in children with high-risk acute lymphoblastic leukemia (ALL). TBI practices are heterogeneous and institution-specific. Since TBI is associated with multiple late adverse effects, recommendations may help to standardize practices and improve the outcome versus toxicity ratio for children. MATERIAL AND METHODS The European Society for Paediatric Oncology (SIOPE) Radiotherapy TBI Working Group together with ESTRO experts conducted a literature search and evaluation regarding myeloablative TBI techniques and toxicities in children. Findings were discussed in bimonthly virtual meetings and consensus recommendations were established. RESULTS Myeloablative TBI in HSCT conditioning is mostly performed for high-risk ALL patients or patients with recurring hematologic malignancies. TBI is discouraged in children <3-4 years old because of increased toxicity risk. Publications regarding TBI are mostly retrospective studies with level III-IV evidence. Preferential TBI dose in children is 12-14.4 Gy in 1.6-2 Gy fractions b.i.d. Dose reduction should be considered for the lungs to <8 Gy, for the kidneys to ≤10 Gy, and for the lenses to <12 Gy, for dose rates ≥6 cGy/min. Highly conformal techniques i.e. TomoTherapy and VMAT TBI or Total Marrow (and/or Lymphoid) Irradiation as implemented in several centers, improve dose homogeneity and organ sparing, and should be evaluated in studies. CONCLUSIONS These ESTRO ACROP / SIOPE recommendations provide expert consensus for conventional and highly conformal myeloablative TBI in children, as well as a supporting literature overview of TBI techniques and toxicities.
-
2.
Population pharmacokinetics of clofarabine for allogeneic hematopoietic cell transplantation in pediatric patients
Nijstad, A. L., Nierkens, S., Lindemans, C. A., Boelens, J. J., Bierings, M., Versluys, A. B., van der Elst, K. C. M., Huitema, A. D. R.
British journal of clinical pharmacology. 2021
Abstract
AIM: Clofarabine has recently been evaluated as part of the conditioning regimen for allogeneic hematopoietic stem cell transplantation (HCT) in children. Pharmacokinetic (PK) exposure of different agents commonly used in conditioning regimens is strongly related to HCT outcome. Consequently, the PK of clofarabine may be important for outcome. This report describes the population PK of clofarabine in pediatric patients and one adult. METHODS From 80 pediatric (0.5-18 years) and 1 adult patient (37 years), 805 plasma concentrations were included in pharmacokinetic analyses using non-linear mixed effects modelling. RESULTS A two-compartment model adequately described the PK of clofarabine. Body weight and estimated glomerular filtration rate (eGFR) were included as covariates. Clearance was differentiated into non-renal and renal clearance (approximately 55% of total clearance), resulting in population estimates of 24.0 L/h (95% confidence interval (CI) 13.7-34.4) and 29.8 L/h (95% CI 23.9-36.1) for a patient of 70 kg with normal renal function, respectively. Unexplained interindividual variability in clearance was 17.8% (95% CI 14.6%-22.4%). A high variability in exposure was observed (range area under the curve(T0-inf) 1.8-6.0 mg/L*h) after body surface area (BSA) based dosing. Interestingly, children with low body weight had a lower exposure than children with a higher body weight, which indicates that the currently practiced BSA based dosing is not adequate for clofarabine. CONCLUSION A clofarabine dosing algorithm based on this PK model, using body weight and eGFR, results in a more predictable exposure than BSA based dosing. However, the exact target exposure needs to be further investigated.
-
3.
Clofarabine-fludarabine-busulfan in HCT for pediatric leukemia: an effective, low toxicity, TBI-free conditioning regimen
Versluijs, B., De Koning, C. C. H., Lankester, A. C., Nierkens, S., Kollen, W. J., Bresters, D., Lindemans, C. A., Boelens, J. J., Bierings, M.
Blood advances. 2021
Abstract
We prospectively studied CloFluBu-conditioning in allogeneic Hematopoietic Cell Therapy (HCT) for lymphoid- and myeloid malignancies, and hypothesized that CloFluBu provides a less toxic alternative to conventional conditioning regimens, with adequate anti-leukemic activity. All patients receiving their first HCT, from 2011-2019, were included and received CloFluBu. Primary endpoint was Event Free Survival (EFS). Secondary endpoints were Overall Survival (OS), Graft-versus-Host-Disease (GvHD)-Relapse-Free Survival (GRFS), Treatment Related Mortality (TRM), Cumulative Incidence of Relapse (CIR), acute and chronic GvHD, and veno-occlusive disease (VOD). Cox Proportional Hazard- and Fine and Gray competing-risk models were used for data analysis. 155 Children were included; 60 acute lymphoid leukemia (ALL), 69 acute myeloid leukemia (AML), and 26 other malignancies (mostly MDS-EB). Median age was 9.7 (0.5-18.6) years. Estimated 2-yr EFS was 72.0% ± 6.0 in ALL, and 62.4% ± 6.0 in AML patients. TRM in the whole cohort was 11.0% ± 2.6, incidence of aGvHD III-IV at 6 months was 12.3% ± 2.7, extensive chronic GvHD at 2-yr was 6.4% ± 2.1. Minimal residual disease-positivity prior to HCT was associated with higher CIR, both in ALL and AML. CloFluBu showed limited toxicity and encouraging EFS. CloFluBu is a potentially less toxic alternative to conventional conditioning regimens. Randomized prospective studies are needed.
-
4.
Myeloablative conditioning for allo-HSCT in pediatric ALL: FTBI or chemotherapy?-A multicenter EBMT-PDWP study
Willasch, A. M., Peters, C., Sedlacek, P., Dalle, J. H., Kitra-Roussou, V., Yesilipek, A., Wachowiak, J., Lankester, A., Prete, A., Hamidieh, A. A., et al
Bone marrow transplantation. 2020
Abstract
Although most children with acute lymphoblastic leukemia (ALL) receive fractionated total body irradiation (FTBI) as myeloablative conditioning (MAC) for allogeneic hematopoietic stem cell transplantation (allo-HSCT), it is an important matter of debate if chemotherapy can effectively replace FTBI. To compare outcomes after FTBI versus chemotherapy-based conditioning (CC), we performed a retrospective EBMT registry study. Children aged 2-18 years after MAC for first allo-HSCT of bone marrow (BM) or peripheral blood stem cells (PBSC) from matched-related (MRD) or unrelated donors (UD) in first (CR1) or second remission (CR2) between 2000 and 2012 were included. Propensity score weighting was used to control pretreatment imbalances of the observed variables. 3.054 patients were analyzed. CR1 (1.498): median follow-up (FU) after FTBI (1.285) and CC (213) was 6.8 and 6.1 years. Survivals were not significantly different. CR2 (1.556): median FU after FTBI (1.345) and CC (211) was 6.2 years. Outcomes after FTBI were superior as compared with CC with regard to overall survival (OS), leukemia-free survival (LFS), relapse incidence (RI), and nonrelapse mortality (NRM). However, we must emphasize the preliminary character of the results of this retrospective "real-world-practice" study. These findings will be prospectively assessed in the ALL SCTped 2012 FORUM trial.
-
5.
Total Body Irradiation or Chemotherapy Conditioning in Childhood ALL: A Multinational, Randomized, Noninferiority Phase III Study
Peters, C., Dalle, J. H., Locatelli, F., Poetschger, U., Sedlacek, P., Buechner, J., Shaw, P. J., Staciuk, R., Ifversen, M., Pichler, H., et al
Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2020;:Jco2002529
-
-
-
-
Free full text
-
-
Editor's Choice
Abstract
PURPOSE Total body irradiation (TBI) before allogeneic hematopoietic stem cell transplantation (HSCT) in pediatric patients with acute lymphoblastic leukemia (ALL) is efficacious, but long-term side effects are concerning. We investigated whether preparative combination chemotherapy could replace TBI in such patients. PATIENTS AND METHODS FORUM is a randomized, controlled, open-label, international, multicenter, phase III, noninferiority study. Patients = 18 years at diagnosis, 4-21 years at HSCT, in complete remission pre-HSCT, and with an HLA-compatible related or unrelated donor were randomly assigned to myeloablative conditioning with fractionated 12 Gy TBI and etoposide versus fludarabine, thiotepa, and either busulfan or treosulfan. The noninferiority margin was 8%. With 1,000 patients randomly assigned in 5 years, 2-year minimum follow-up, and one-sided alpha of 5%, 80% power was calculated. A futility stopping rule would halt random assignment if chemoconditioning was significantly inferior to TBI (EudraCT: 2012-003032-22; ClinicalTrials.gov: NCT01949129). RESULTS Between April 2013 and December 2018, 543 patients were screened, 417 were randomly assigned, 212 received TBI, and 201 received chemoconditioning. The stopping rule was applied on March 31, 2019. The median follow-up was 2.1 years. In the intention-to-treat population, 2-year overall survival (OS) was significantly higher following TBI (0.91; 95% CI, 0.86 to 0.95; P < .0001) versus chemoconditioning (0.75; 95% CI, 0.67 to 0.81). Two-year cumulative incidence of relapse and treatment-related mortality were 0.12 (95% CI, 0.08 to 0.17; P < .0001) and 0.02 (95% CI, < 0.01 to 0.05; P = .0269) following TBI and 0.33 (95% CI, 0.25 to 0.40) and 0.09 (95% CI, 0.05 to 0.14) following chemoconditioning, respectively. CONCLUSION Improved OS and lower relapse risk were observed following TBI plus etoposide compared with chemoconditioning. We therefore recommend TBI plus etoposide for patients > 4 years old with high-risk ALL undergoing allogeneic HSCT.
Clinical Commentary
Dr. Julia Wolf, University Hospitals Bristol and Weston NHS Foundation Trust
What is known?
Allogeneic haematopoietic stem cell transplantation (HSCT) provides a potential curative treatment option for paediatric patients with high risk acute lymphoblastic leukaemia (ALL). Pre-transplant conditioning regimes with total body irradiation (TBI) have resulted in encouraging overall and relapse-free survival but may cause serious long-term side effects. As a result, several studies have investigated TBI-free regimes. A large meta-analysis (1) which included seven randomised controlled trials comparing TBI-based with chemoconditioning regimes demonstrated significantly lower treatment related mortality (TRM) but no overall survival (OS) advantage with TBI-based regimes. A further small randomised study (2) found significantly higher event-free survival (EFS) with TBI-based regimes in patients with unrelated donors, but a non-significant difference only in patients with matched sibling donors. Concerns about late effects of TBI on growth, cognitive function and secondary malignancy however remain. A single centre retrospective study (3) in paediatric ALL concluded that triosulphan based regimes were safe and efficacious while a similar review (4) in adult patients suggested that busulphan and clofarabine could provide an alternative to TBI. This paper reports on the FORUM study. It compares TBI with chemoconditioning regimes to investigate whether optimal chemoconditioning regimens could replace TBI in paediatric patients with high-risk ALL.
What did this paper set out to examine?
This is the largest randomised, controlled, open-label, international, multicentre, phase III trial comparing TBI plus etoposide with chemoconditioning (fludarabine, thiotepa and busulfan or triosulfan) in paediatric ALL to date. It investigates whether chemoconditioning is non-inferior to TBI-based regimes with the primary endpoint of OS. It is also the first study to directly and prospectively compare these regimes in terms of disease-free survival and short- and long-term adverse events. The study aimed to recruit 1000 patients.
What did they show?
Improved OS and lower relapse risk were observed following TBI plus etoposide compared with chemoconditioning. Patients ≤18 years old at diagnosis and aged 4-21 at HSCT with high risk ALL in complete morphological remission with HLA compatible related or unrelated donor were included in the study. Patients were randomised 1:1 to 12Gy TBI with etoposide versus fludarabine, thiotepa and busulfan or triosulphan conditioning. Patients were well matched for baseline characteristics and demographics. Randomisation was stopped early due significant inferiority of chemoconditioning compared with TBI-based regime.
Results
Following randomisation of 417 patients, a futility stopping rule was applied because patients receiving chemoconditioning with fludarabine, thiotepa, and busulfan or treosulfan had inferior OS to those receiving TBI plus etoposide. Two-year OS was 0.91 (95% CI, P <.0001) following TBI versus 0.75 (95% CI) following chemoconditioning. Median follow up was 2.1 years. Relapse was the commonest reason for treatment failure and out of 67 patients who relapsed, there was no difference in OS between conditioning regimes. There was no difference in serious adverse events or GvHD rates between the groups.
What are the implications for practice and for future work?
While TBI is associated with potentially serious long-term side effects, this study supports growing evidence demonstrating improved outcomes for patients undergoing TBI-based conditioning. Here patients receiving TBI-based conditioning had a significantly lower risk of relapse and TRM than those given chemoconditioning.
Of note, TRM in this trial was low compared to previously reported studies. FOCUS reported a 2-year OS and EFS rate of 0.91 and 0.91 respectively, which is the lowest documented TRM in HSCT for high-risk paediatric ALL to date. Additionally, other risk factors thought to impact on outcomes (e.g. leukaemia phenotype, MRD pre-transplant, donor type, etc) were not found to be significant in FOCUS. Only remission status (CR1 vs CR2) and conditioning regime influenced OS and EFS. This may be in part explained by the strong attempts within this study to reduce MRD prior to HSCT in all patients.
This was a noninferiority study which required a sample size of 1000 patients with 2-year minimum follow-up to make analysis of primary outcomes feasible. As the majority of relapses in paediatric ALL occur in the first 24 months, it is unlikely that longer follow up would result in dramatic changes to outcomes.
Non-randomised recruitment in FORUM to assess long-term side effects of TBI, such as secondary malignancy, in FORUM is ongoing. However, no difference in adverse events or incidence of GvHD was found between study groups. The study reports a composite end point of 2-year GVHD-free, relapse-free survival of 72% (95% CI) following TBI plus etoposide and 51% (95% CI, p= .0003) following chemoconditioning which might be a benchmark for future investigations.
PICO Summary
Population
Patients diagnosed with acute lymphoblastic leukaemia at or before 18 years of age, who underwent HSCT aged 4-21 years (n=413)
Intervention
TBI conditioning (n=212)
Comparison
Chemoconditioning: fludarabine, thiotepa, and either busulfan or treosulfan (n=201)
Outcome
The median follow-up was 2.1 years. In the intention-to-treat population, 2-year overall survival (OS) was significantly higher following TBI (0.91) versus chemoconditioning (0.75). Two-year cumulative incidence of relapse and treatment-related mortality were 0.12 and 0.02 following TBI and 0.33 and 0.09 following chemoconditioning, respectively.
-
6.
Gonadal function after Busulfan compared to Treosulfan in children and adolescents undergoing allogeneic hematopoietic stem cell transplantation. On Behalf of the Pediatric and Transplant Complications Working Parties of EBMT
Faraci, M., Diesch, T., Labopin, M., Dalissier, A., Lankester, A., Gennery, A., Sundin, M., Uckan-Cetinkaya, D., Bierings, M., Peters, A. M. J., et al
Biology of blood and marrow transplantation : journal of the American Society for Blood and Marrow Transplantation. 2019
Abstract
INTRODUCTION Gonadal impairment is an important late effect having a significant impact on quality of life of transplanted patients. The aim of this study was to compare gonadal function after Busulfan (Bu) or Treosulfan (Treo) conditioning regimens in pre and post-pubertal children. MATERIAL AND METHODS This is a retrospective, multicenter study including children transplanted in pediatric European Society for Blood and Marrow Transplantation (EBMT) centers between 1992 and 2012 who did not receive gonadotoxic chemo-radiotherapy before the transplant. RESULTS We evaluated 137 patients transplanted in 25 pediatric EBMT centers. Median age at transplant was 11.04 years (range 5-18); 89 patients were males and 48 were females. Eighty-nine patients were pre-pubertal at transplant, while 48 were post-pubertal. One hundred eighteen children received Bu and 19 Treo. A higher proportion of females treated with Treo in pre-pubertal stage reached spontaneous puberty compared to those treated with Bu (p=0.02). Spontaneous menarche was more frequent after Treo than after Bu (p< 0.001). Post-pubertal males and females treated with Treo had significantly lower luteinizing hormone (LH) levels (p=0.03 and p=0.04, respectively) compared to the Bu group. CONCLUSIONS Frequency of gonadal damage associated with Treo was significantly lower than that observed after Bu. These results need to be confirmed in a larger population.
-
7.
Fludarabine exposure in the conditioning prior to allogeneic hematopoietic cell transplantation predicts outcomes
Langenhorst, J. B., van Kesteren, C., van Maarseveen, E. M., Dorlo, T. P. C., Nierkens, S., Lindemans, C. A., de Witte, M. A., van Rhenen, A., Raijmakers, R., Bierings, M., et al
Blood advances. 2019;3(14):2179-2187
-
-
Free full text
-
Abstract
Fludarabine is the most frequently used agent in conditioning regimens for allogeneic hematopoietic cell transplantation (HCT). Body surface area-based dosing leads to highly variable fludarabine exposure. We studied the relation between fludarabine exposure and clinical outcomes. A retrospective, pharmacokinetic-pharmacodynamic analysis was conducted with data from patients undergoing HCT with fludarabine (160 mg/m(2)) as part of a myeloablative conditioning (busulfan targeted to an area under the plasma-concentration-time curve [AUC] of 90 mg*h/L) and rabbit antithymocyte globulin (6-10 mg/kg; from day -9/-12) between 2010 and 2016. Fludarabine exposure as AUC was calculated for each patient using a previously published population pharmacokinetic model and related to 2-year event-free survival (EFS) by means of (parametric) time-to-event models. Relapse, nonrelapse mortality (NRM), and graft failure were considered events. One hundred ninety-two patients were included (68 benign and 124 malignant disorders). The optimal fludarabine exposure was determined as an AUC of 20 mg*h/L. In the overexposed group, EFS was lower (hazard ratio [HR], 2.0; 95% confidence interval [CI], 1.1-3.5; P = .02), due to higher NRM (HR, 3.4; 95% CI, 1.6-6.9; P <001) associated with impaired immune reconstitution (HR, 0.43; 95% CI, 0.26-0.70; P <001). The risks of NRM and graft failure were increased in the underexposed group (HR, 3.3; 95% CI, 1.2-9.4; P = .02; HR, 4.8; 95% CI, 1.2-19; P = .02, respectively). No relationship with relapse was found. Fludarabine exposure is a strong predictor of survival after HCT, stressing the importance of optimum fludarabine dosing. Individualized dosing, based on weight and "renal function" or "therapeutic drug monitoring," to achieve optimal fludarabine exposure might improve survival.
-
8.
Association of busulfan exposure with survival and toxicity after haemopoietic cell transplantation in children and young adults: a multicentre, retrospective cohort analysis
Bartelink, I. H., Lalmohamed, A., van Reij, E. M., Dvorak, C. C., Savic, R. M., Zwaveling, J., Bredius, R. G., Egberts, A. C., Bierings, M., Kletzel, M., et al
The Lancet Haematology. 2016;3(11):e526-e536
Abstract
BACKGROUND Intravenous busulfan combined with therapeutic drug monitoring to guide dosing improves outcomes after allogeneic haemopoietic cell transplantation (HCT). The best method to estimate busulfan exposure and optimum exposure in children or young adults remains unclear. We therefore assessed three approaches to estimate intravenous busulfan exposure (expressed as cumulative area under the curve [AUC]) and associated busulfan AUC with clinical outcomes in children or young adults undergoing allogeneic HCT. METHODS In this retrospective analysis, patients from 15 centres in the Netherlands, USA, Canada, Switzerland, UK, Italy, Germany, and Australia who received a busulfan-based conditioning regimen between March 18, 2001, and Feb 12, 2015, were included. Cumulative AUC was calculated by numerical integration using non-linear mixed effect modelling (AUCNONMEM), non-compartmental analysis (AUC from 0 to infinity [AUC0-] and to the next dose [AUC0-tau]), and by individual centres using various approaches (AUCcentre). The main outcome of interest was event-free survival. Other outcomes of interest were graft failure or relapse, or both; transplantation-related mortality; acute toxicity (veno-occlusive disease or acute graft versus-host disease [GvHD]); chronic GvHD; overall survival; and chronic-GvHD-free event-free survival. We used propensity-score-adjusted Cox proportional hazard models, Weibull models, and Fine-Gray competing risk regressions for statistical analyses. FINDINGS 790 patients were enrolled, 674 of whom were included: 274 (41%) with malignant and 400 (59%) with non-malignant disease. Median age was 4.5 years (IQR 1.4-10.7). The median busulfan AUCNONMEM was 74.4 mg x h/L (95% CI 31.1-104.6), which correlated with the standardised method AUC0- (r2=0.74), but the latter correlated poorly with AUCcentre (r2=0.35). Estimated 2-year event-free survival was 69.7% (95% CI 66.2-73.0). Event-free survival at 2 years was 77.0% (95% CI 72.1-82.9) in the 257 patients with an optimum intravenous busulfan AUC of 78-101 mg x h/L compared with 66.1% (60.9-71.4) in the 235 patients at the low historical target of 58-86 mg x h/L and 49.5% (29.2-66.0) in the 44 patients with a high (>101 mg x h/L) busulfan AUC (p=0.011). Compared with the low AUC group, graft failure or relapse occurred less frequently in the optimum AUC group (hazard ratio [HR] 0.57, 95% CI 0.39-0.84; p=0.0041). Acute toxicity (HR 1.69, 1.12-2.57; p=0.013) and transplantation-related mortality (2.99, 1.82-4.92; p<0.0001) were significantly higher in the high AUC group (>101 mg x h/L) than in the low AUC group (<78 mg x h/L), independent of indication; no difference was noted between AUC groups for chronic GvHD (<78 mg x h/L vs >=78 mg x h/L, HR 1.30, 95% CI 0.73-2.33; p=0.37). INTERPRETATION Improved clinical outcomes are likely to be achieved by targeting the busulfan AUC to 78-101 mg x h/L using a new validated pharmacokinetic model for all indications. FUNDING Research Allocation Program and the UCSF Helen Friller Family Comprehensive Cancer Center and the Mt Zion Health Fund of the University of California, San Francisco.Copyright © 2016 Elsevier Ltd. All rights reserved.