Treosulfan-based conditioning regimens for allogeneic HSCT in children with acute lymphoblastic leukaemia

Oral Mucositis and Nutritional Status in Children Who Underwent Hematopoietic Cell Transplantation: A Comparison Between Nonmalignant and Malignant Primary Diseases

BACKGROUND

There is a lack of studies analyzing the association between oral mucositis (OM) and nutritional imbalance in children during hematopoietic stem cell transplantation (HSCT). The aim of this study was to compare the risk factors for OM and nutritional imbalance during HSCT in pediatric patients with nonmalignant diseases (NMD) and malignant diseases (MD).

METHODS

Data on age, sex, primary disease, transplantation type, conditioning regimen, GVHD prophylaxis, gastrointestinal toxicity, OM, percent body weight loss or gain, nutritional repositioning, and overall survival (OS) were retrospectively collected from the 132 medical records. The data were then compared between patients with NMD (n = 70) and MD (n = 62).

RESULTS

OM had a similar severity between the groups. The primary risk factor for OM in the NMD group was the conditioning regimen with busulfan, while in the MD group it was GVHD prophylaxis with cyclosporin and methotrexate. OM did not have an impact on body weight loss or gain in any of the groups. In the NMD, body weight gain due to fluid overload was more pronounced and associated with a lower age range. OS was similar between the groups and was not affected by OM.

CONCLUSIONS

OM pattern was similar in pediatric patients with or without MD, but the factors that determined these oral lesions were different. There were disparities in body weight changes between the two groups, and these changes were not associated to OM.

Alemtuzumab, Dual Graft-versus-Host Disease Prophylaxis, and Lower CD3+ T Cell Doses Equalize Rates of Acute and Chronic Graft-versus-Host Disease in Pediatric Patients Receiving Allogeneic Hematopoietic Stem Cell Transplantation with Matched Unrelated Donor Peripheral Blood Stem Cells or Bone Marrow Grafts

Data comparing hematopoietic stem cell transplantation (HSCT) using bone marrow (BM) or peripheral blood stem cell (PBSC) grafts in children after alemtuzumab-based conditioning are lacking. We investigated whether in vivo T cell depletion using alemtuzumab could reduce the risk of severe acute graft-versus-host disease (aGVHD) and chronic GVHD (cGVHD) after HSCT with matched unrelated donor (MUD) BM or PBSCs. This retrospective multicenter study included 397 children (BM group, n = 202; PBSC group, n = 195) who underwent first MUD HSCT at 9 pediatric centers in the United Kingdom between 2015 and 2019. The median age at transplantation was 7.0 years (range, .1 to 19.3 years), and the median duration of follow-up was 3.1 years (range, .3 to 7.5 years). The 3-year overall survival was 81% for the entire cohort (BM group, 80%; PBSC group, 81%). The incidence of grade II-IV aGVHD was significantly higher in the PBSC group (31%) compared to the BM group (31% versus 19%; P = .003), with no difference in the incidence of grade III-IV aGVHD (BM, 7%; PBSC, 12%; P = .17). CD3+ T cell dose >5 × 108/kg and the use of PBSCs were independent predictors of grade II-IV aGVHD. When considering CD3+ T cell dose and GVHD prophylaxis, PBSC transplantation with a calcineurin inhibitor (CNI) and mycophenolate mofetil (MMF) and a CD3+ T cell dose ≤5 × 108/kg had a comparable grade II-IV aGVHD to BM transplantation plus a CNI (20% versus 18%; P = .52). PBSC transplantation was associated with a lower incidence of cGVHD compared to BM transplantation (6% versus 11%; P = .03). Within the limits of this study, we identified a potential strategy to reduce the risk of severe GVHD in pediatric PBSC recipients that includes a combination of in vivo T cell depletion using alemtuzumab and dual GVHD prophylaxis (with a CNI and MMF) and limiting the CD3+ T cell dose to ≤5 × 108/kg.

Improvement of survival after hematopoietic stem cell transplantation and trends at a pediatric transplantation center; a three-decade journey

BACKGROUND

Advances in stem cell transplantation have resulted in improved outcomes.

METHODS

This is a retrospective study aimed to analyze changes in patient profile, transplantation, graft characteristics, and outcome among 241 pediatric patients who received stem cell transplantation in a single center between 1993 and 2019.

RESULTS

In the 2010-2019, compared with the 1993-2009 period, a significantly higher 5-year overall survival (60% vs. 44%, p = .022) and an event-free survival (53% vs. 34%, p = .025) were observed. Cumulative incidence of deaths due to relapse or progression between the 1993-2009 and 2010-2019 periods were 33% and 26% respectively (p = .66). Cumulative incidence of non-relapse mortality was significantly higher during the 1993-2009 period compared with the 2010-2019 period for malignant diseases (57.7% vs. 28.3%, p = .007). The overall survival from acute graft-versus-host disease between 1993 and 2009 was 11% versus 46% between 2010 and 2019 (p = .0001). The overall survival from infection in both eras did not show any difference (p = .41).

CONCLUSIONS

Development in transplantation technology has led to a decrease in non-relapse mortality and better control of graft-versus-host disease. However, relapse and infection remained as major causes of death. Studies evaluating institutional trends in patients undergoing HSCT and analyzing their mortality profile, can improve the management of patients, leading to a reduction in transplant-related problems.

Treosulfan-Based Conditioning Regimen In Pediatric Hematopoietic Stem Cell Transplantation: A Retrospective Analysis on Behalf of the Spanish Group for Hematopoietic Transplantation and Cellular Therapy (GETH-TC)

Increasing data on treosulfan-based conditioning regimens before hematopoietic stem cell transplantation (HSCT) demonstrate the consistent benefits of this approach, particularly regarding acute toxicity. This study aimed to describe the results of treosulfan-based conditioning regimens in children, focusing on toxicity and outcomes when used to treat both malignant and nonmalignant diseases. This retrospective observational study of pediatric patients treated in Spain with treosulfan-based conditioning regimens before HSCT was based on data collection from electronic clinical records. We studied a total of 160 treosulfan-based conditioning HSCTs to treat nonmalignant diseases (n = 117) or malignant diseases (n = 43) in 158 children and adolescents. The median patient age at HSCT was 5.1 years (interquartile range, 2 to 10 years). The most frequent diagnoses were primary immunodeficiency (n = 42; 36%) and sickle cell disease (n = 42; 36%) in the nonmalignant disease cohort and acute lymphoblastic leukemia (n = 15; 35%) in the malignant disease cohort. Engraftment occurred in 97% of the patients. The median times to neutrophil engraftment (17 days versus 14 days; P = .008) and platelet engraftment (20 days versus 15 days; P = .002) were linger in the nonmalignant cohort. The 1-year cumulative incidence of veno-occlusive disease was 7.98% (95% confidence interval [CI], 4.6% to 13.6%), with no significant differences between cohorts. The 1-year cumulative incidence of grade III-IV acute graft-versus-host disease (GVHD) was higher in the malignant disease cohort (18% versus 3.2%; P = .011). Overall, the malignant cohort had both a higher total incidence (9% versus 3%; P < .001) and a higher 2-year cumulative incidence (16% versus 1.9%; P < .001) of total chronic GVHD. The 2-year cumulative transplantation-related mortality was 15%, with no difference between the 2 cohorts. The 5-year overall survival was 80% (95% CI, 72% to 86%) and was higher in the nonmalignant cohort (87% versus 61%; P = .01). The 2-year cumulative incidence of relapse was 25% in the malignant cohort. The 5-year cumulative GVHD-free, relapse-free survival rate was 60% (95% CI, 51% to 70%) and was higher in the nonmalignant cohort (72% versus 22%; P < .001). A treosulfan-based radiation-free conditioning regimen is feasible, achieving a high engraftment rate and 5-year overall survival, and is an emerging option for the first HSCT in nonmalignant diseases.

The current landscape: Allogeneic hematopoietic stem cell transplant for acute lymphoblastic leukemia

One of the consistent features in development of hematopoietic stem cell transplant (HCT) for Acute Lymphoblastic Leukemia (ALL) is the rapidity with which discoveries in the laboratory are translated into innovations in clinical care. Just a few years after murine studies demonstrated that rescue from radiation induced marrow failure is mediated by cellular not humoral factors, E. Donnall Thomas reported on the transfer of bone marrow cells into irradiated leukemia patients. This was followed quickly by the first descriptions of Graft versus Leukemia (GvL) effect and Graft versus Host Disease (GvHD). Despite the pivotal nature of these findings, early human transplants were uniformly unsuccessful and identified the challenges that continue to thwart transplanters today - leukemic relapse, regimen related toxicity, and GvHD. While originally only an option for young, fit patients with a matched family donor, expansion of the donor pool to include unrelated donors, umbilical cord blood units, and more recently the growing use of haploidentical donors have all made transplant a more accessible therapy for patients with ALL. Novel agents for conditioning, prevention and treatment of GvHD have improved outcomes and investigators continue to develop novel treatment strategies that balance regimen related toxicity with disease control. Our evolving understanding of how to prevent and treat GvHD and how to prevent relapse are incorporated into novel clinical trials that are expected to further improve outcomes. Here we review current considerations and future directions for both adult and pediatric patients undergoing HCT for ALL, including indication for transplant, donor selection, cytoreductive regimens, and outcomes.

First experience of total body irradiation in conditioning regimes for allogenic hematopoietic stem cells transplantation in children with acute lymphoblastic leukemia in Saint Petersburg

Background. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective treatment method of refractory and recurrent forms of acute leukemia in children, while the question of choosing a conditioning regimen in order to achieve the best treatment results remains debatable. Conditioning based on total body irradiation (TbI) was confirmed to be most effective in some trials, but there are still issues of overcoming early and late toxicity, as well   as difficulties in planning and routing patients.Aim. To share the experience of interdisciplinary patient management during the conditioning period with TbI inclusion in Saint petersburg, to evaluate the feasibility, toxicity and effectiveness of the method.Materials and methods. patients undergoing allo-HSCT for high risk acute lymphoblastic leukemia conditioned either with TbI (n = 12) or chemotherapy (n = 10) were included. Medical data were retrospectively analyzed with an assessment of the following transplant outcomes: HSCT-associated toxicity, the frequency and severity of infectious complications, graft versus host disease, as well as overall and event-free survival rates. we have evaluated radiotherapy plans in order to assess the compliance of radiation exposure with acceptable values for critical organs.Results. All patients with acute lymphoblastic leukemia in both groups received appropriate myeloablative conditioning. According to the study results, despite the lack of significance, we obtained differences in HSCT-associated mortality (8.3 and 30 %; p = 0.151), 2-years overall and event-free survival (66 ± 13.6 and 36 ± 16.1 %; p = 0.122) in group with TbI and HdCT respectively. It should be noted that there was a trend towards a decrease of toxic reactions frequency in case of TbI-containing regimens; however we didn’t reveal any significant differences in the number of infectious complications during post-transplant period. The median follow-up was 24.2 months and there were no signs of delayed toxicity.Conclusion. TbI-based conditioning was well tolerated with a low incidence of early and delayed toxicity, better overall and event-free survival. based on feasibility of TbI in Saint petersburg hospitals it is possible to recommend the method in routine practice, taking into account clinical indications.

A retrospective study of treosulfan versus busulfan-based conditioning in pediatric patients

OBJECTIVES

To compare the outcomes of treosulfan-based vs. busulfan-based conditioning regimens in allogeneic hematopoietic stem cell transplantation (HSCT) in pediatric patients.

METHODS

Retrospective study of all consecutive patients (2012-2019) treated with allogenic HSCT and treosulfan- or busulfan-based conditioning regimens at a single center.

RESULTS

A total of 101 HSCT were included: 66 HSCT with busulfan and 35 with treosulfan. In malignant diseases (n=62), busulfan-based conditioning was more commonly employed than treosulfan: 82.3% vs. 17.7%. However, the use of treosulfan for malignant diseases increased over time: 6.5% of HSCT in 2012-2015 vs. 29% of HSCT in 2015-2019 (P=0.02). The cohort of treosulfan had more children under 1-year of age than the busulfan cohort (31 vs. 13%; P=0.033). The percentage of patients who received serotherapy was 73 and 89% in the non-malignant and malignant groups respectively. The engraftment, time to neutrophil, and platelet engraftment were not significantly different between the busulfan and the treosulfan cohorts. Rate of grade II-IV acute GvHD was significantly higher in the busulfan cohort than the treosulfan cohort (39% vs. 15%; P=0.016). No differences were observed in endothelial damage complications, chronic GvHD, relapse, overall survival, and transplant-related mortality.

CONCLUSIONS

Busulfan-based conditioning regimens are used more frequently for children undergoing allogenic HSCT, but treosulfan-based conditioning is gaining acceptance. Treosulfan-based conditioning is associated with lower rates of acute GvHD, and no significant differences on overall survival were observed compared with busulfan.

Hematopoietic stem cell transplantation for infants with high-risk KMT2A gene-rearranged acute lymphoblastic leukemia

The role of allogeneic hematopoietic stem cell transplantation (HSCT) for infants with acute lymphoblastic leukemia (ALL) and KMT2A gene rearrangement (KMT2A-r) is controversial in terms of both its efficacy and potential for acute and late toxicities. In Japanese Pediatric Leukemia/Lymphoma Study Group trial MLL-10, by introducing intensive chemotherapy, indication of HSCT was restricted to patients with high-risk (HR) features only (KMT2A-r and either age <180 days or presence of central nervous system leukemia). Of the 56 HR patients, 49 achieved complete remission. Forty-three patients received HSCT in first remission including 38 patients receiving protocol-specified HSCT with conditioning consisting of individualized targeted doses of busulfan, etoposide, and cyclophosphamide. Three-year event-free survival (EFS) of 56.8% (95% confidence interval [CI], 42.4% to 68.8%) and overall survival of 80.2% (95% CI, 67.1% to 88.5%) were accomplished. Univariable analysis showed that Interfant-HR criteria and flow cytometric minimal residual disease (MRD; ≥0.01%), both at the end of induction and at the end of consolidation (EOC), were significantly associated with poorer EFS. In the multivariable analysis, positive MRD at EOC was solely associated with poor EFS (P < .001). Rapid pretransplant MRD clearance and tailored HSCT strategy in the MLL-10 trial resulted in a favorable outcome for infants with HR KMT2A-r ALL. However, considering the high rate of potentially life-threatening toxicities and the risk of late effects, its indication should be further restricted or even eliminated in the future by introducing more effective therapeutic modalities with minimal toxicities. This trial was registered at the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) as #UMIN000004801.

Impact of Treosulfan Exposure on Early and Long-Term Clinical Outcomes in Pediatric Allogeneic Hematopoietic Stem Cell Transplantation Recipients: A Prospective Multicenter Study

Treosulfan-based conditioning has gained popularity in pediatric allogeneic hematopoietic stem cell transplantation (HSCT) because of its presumed favorable efficacy and toxicity profile. Treosulfan is used in standardized dosing regimens based on body surface area. The relationships between systemic treosulfan exposure and early and long-term clinical outcomes in pediatric patients undergoing allogeneic HSCT for nonmalignant diseases remain unclear. In this a multicenter, prospective observational study, we assessed the association between treosulfan exposure and early and, in particular, long-term clinical outcomes. Our study cohort comprised 110 pediatric patients with nonmalignant diseases who underwent HSCT between 2011 and 2019 in Leiden, The Netherlands and Rome, Italy. Blood samples were collected, and treosulfan area under the receiver operating characteristic curve (AUC_0-∞) was estimated as a measure of exposure. Cox proportional hazard survival analyses were performed to assess the relationships between treosulfan exposure and overall survival (OS) and event-free survival (EFS). The predictive value of systemic treosulfan exposure for the occurrence of toxicity within 28 days was evaluated using a multivariable logistic regression analysis. In the overall cohort, OS and EFS at 2 years were 89.0% and 75.3%, respectively, with an excellent OS of 97% in children age <2 years. The occurrence of grade II-IV acute graft-versus-host disease, the level of 1-year whole blood chimerism, and 2-year OS and EFS were not correlated with treosulfan exposure. The occurrence of skin toxicity (odds ratio [OR], 3.97; 95% confidence interval [CI], 1.26-13.68; P = .02) and all-grade mucositis (OR, 4.43; 95% CI, 1.43-15.50; P = .02), but not grade ≥2 mucositis (OR, 1.51; 95% CI, 0.52 to 4.58; P = .46) was related to high treosulfan exposure (>1750 mg*h/L). Our study demonstrates that standardized treosulfan-based conditioning results in a favorable OS and EFS in infants and children with nonmalignant diseases, independent of interindividual variation in treosulfan exposure. These outcomes can be achieved without the need for therapeutic drug monitoring, thereby emphasizing the advantage of treosulfan use in this category of patients. Although higher treosulfan exposure increases the risk of skin toxicity, there is no absolute necessity for therapeutic drug monitoring if proper preventive skin measures are taken. More research is needed to assess whether deescalation of treosulfan doses is possible to minimize early and long-term toxicity without compromising efficacy.

Treosulfan-induced myalgia in pediatric hematopoietic stem cell transplantation identified by an electronic health record text mining tool

Treosulfan is increasingly used as myeloablative agent in conditioning regimen prior to allogeneic hematopoietic stem cell transplantation (HSCT). In our pediatric HSCT program, myalgia was regularly observed after treosulfan-based conditioning, which is a relatively unknown side effect. Using a natural language processing and text-mining tool (CDC), we investigated whether treosulfan compared with busulfan was associated with an increased risk of myalgia. Furthermore, among treosulfan users, we studied the characteristics of given treatment of myalgia, and studied prognostic factors for developing myalgia during treosulfan use. Electronic Health Records (EHRs) until 28 days after HSCT were screened using the CDC for myalgia and 22 synonyms. Time to myalgia, location of pain, duration, severity and drug treatment were collected. Pain severity was classified according to the WHO pain relief ladder. Logistic regression was performed to assess prognostic factors. 114 patients received treosulfan and 92 busulfan. Myalgia was reported in 37 patients; 34 patients in the treosulfan group and 3 patients in the busulfan group (p = 0.01). In the treosulfan group, median time to myalgia was 7 days (0–12) and median duration of pain was 19 days (4–73). 44% of patients needed strong acting opiates and adjuvant medicines (e.g. ketamine). Hemoglobinopathy was a significant risk factor, as compared to other underlying diseases (OR 7.16 95% CI 2.09–30.03, p = 0.003). Myalgia appears to be a common adverse effect of treosulfan in pediatric HSCT, especially in hemoglobinopathy. Using the CDC, EHRs were easily screened to detect this previously unknown side effect, proving the effectiveness of the tool. Recognition of treosulfan-induced myalgia is important for adequate pain management strategies and thereby for improving the quality of hospital stay.

The Role of Allogeneic Hematopoietic Stem Cell Transplantation in Pediatric Leukemia

Allogeneic hematopoietic stem cell transplantation (HSCT) offers potentially curative treatment for many children with high-risk or relapsed acute leukemia (AL), thanks to the combination of intense preparative radio/chemotherapy and the graft-versus-leukemia (GvL) effect. Over the years, progress in high-resolution donor typing, choice of conditioning regimen, graft-versus-host disease (GvHD) prophylaxis and supportive care measures have continuously improved overall transplant outcome, and recent successes using alternative donors have extended the potential application of allotransplantation to most patients. In addition, the importance of minimal residual disease (MRD) before and after transplantation is being increasingly clarified and MRD-directed interventions may be employed to further ameliorate leukemia-free survival after allogeneic HSCT. These advances have occurred in parallel with continuous refinements in chemotherapy protocols and the development of targeted therapies, which may redefine the indications for HSCT in the coming years. This review discusses the role of HSCT in childhood AL by analysing transplant indications in both acute lymphoblastic and acute myeloid leukemia, together with current and most promising strategies to further improve transplant outcome, including optimization of conditioning regimen and MRD-directed interventions.

Total Body Irradiation or Chemotherapy Conditioning in Childhood ALL: A Multinational, Randomized, Noninferiority Phase III Study

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.

Acute toxicity and outcome among pediatric allogeneic hematopoietic transplant patients conditioned with treosulfan-based regimens

Treosulfan-based regimens constitute a feasible and increasingly used, but still myeloablative, conditioning in pediatric allogeneic hematopoietic stem cell transplantation (HSCT). We retrospectively analyzed the acute toxicity and outcome of all consecutive (2004-2015) pediatric HSCT patients prepared for HSCT with treosulfan in a single-center setting. We included HSCTs performed for both nonmalignant (n = 23) and malignant diseases (n = 11). The controls were patients with nonmalignant diseases or hematological malignancies conditioned with cyclophosphamide (Cy)-total body irradiation (TBI)-based (39 patients) or busulfan-based regimens (11 patients). The major toxicities of the treosulfan-based regimens were limited to oral mucosa and skin. 50% of the patients needed IV morphine for severe mucositis compared to 31% in patients conditioned with Cy-TBI (P = 0.02). Other toxicities were rare. The disease-free survival (DFS) of patients transplanted for nonmalignant disorders was 88.9 ± 7.5% at 2 years. The event-free survival (EFS) at 2 years in this small cohort for those with a malignant disease and a treosulfan-based conditioning was 54.5 ± 1.5%. We conclude that a treosulfan-based conditioning regimen gives excellent DFS in pediatric HSCT performed for a nonmalignant disorder but with substantial mucosal toxicity. In a malignant disorder a treosulfan-based regimen looks promising but larger, preferably randomized, studies are needed to prove efficacy.

Hematopoietic Stem Cell Transplantation Beyond Severe Combined Immunodeficiency: Seeking a Cure for Primary Immunodeficiency

Hematopoietic stem cell transplantation (HSCT) can provide definitive therapy for patients with primary immunodeficiency disease (PIDD). Modern HSCT techniques and supportive care have significantly improved outcomes for patients with PIDD. This review examines current HSCT practice for PIDD other than severe combined immunodeficiency, and explores indications, risks, and long-term outcomes for this group of challenging diseases.

Cellular Therapies in Chronic Granulomatous Disease

Allogeneic hematopoietic stem cell transplantation (HSCT) has become the main curative treatment in patients with chronic granulomatous disease (CGD). CGD is caused by inherited defects of the phagolysomal NADPH-oxidase, leading to a lifelong propensity for invasive infections and granulomatous inflammation. After successful allogeneic HSCT, chronic infections and inflammation resolve and quality-of-life improves. Favorable long-term outcome after HSCT is dependent on the prevention of primary and secondary graft failure (GF), including falling myeloid donor chimerism (DC) below 10 %, and chronic graft-vs.-host-disease (cGVHD). The risk of GF and GvHD increases with the use of HLA-incompatible donors and this may outweigh the benefits of HSCT, mainly in patients with severe co-morbidities and in asymptomatic patients with residual NADPH-oxidase function. Seventeen scientific papers have reported on a total of 386 CGD-patients treated by HSCT with HLA-matched family/sibling (MFD/MSD), 9/10-/10/10-matched-unrelated volunteer (MUD) and cord blood donors. The median OS/EFS-rate of these 17 studies was 91 and 82%, respectively. The median rates of GF, cGVHD and de-novo autoimmune diseases were 14, 10, and 12%, respectively. Results after MFD/MSD and 10/10-MUD-transplants were rather similar, but outcome in adults with significant co-morbidities and after transplants with 9/10 HLA-MUD were less successful, mainly due to increased GF and chronic GVHD. Transplantation protocols using T-cell depleted haploidentical donors with post-transplant cyclophosphamide or TCR-alpha/beta depletion have recently reported promising results. Autologous gene-therapy after lentiviral transduction of HSC achieved OS/EFS-rates of 78/67%, respectively. Careful retrospective and prospective studies are mandatory to ascertain the most effective cellular therapies in patients with CGD.

Haploidentical hematopoietic stem cell transplantation with post-transplant high-dose cyclophosphamide in high-risk children: A single-center study

BACKGROUND

Post-Cy administration for GVHD prophylaxis in unmanipulated haploidentical HSCT has resulted in improved outcomes in recent years. Studies in children are lacking and accordingly we present the outcomes of 62 haploidentical transplantation for high-risk children.

PROCEDURE

We retrospectively assessed 62 transplants in 60 patients who underwent haploidentical-related HSCT with unmanipulated stem cells and for whom Post-Cy was used for GVHD prophylaxis.

RESULTS

Myeloid reconstitution was achieved on day + 30 for 57 of the 62 patients. The median follow-up of the surviving 39 patients (63%) was 26 months, with a range of 6-57 months. The OS and EFS at 2 years were 64.6% (52.0%-77.2%, 95% CI) and 58.9% (46.1%-71.7%, 95% CI), respectively. The only factor in our multivariate analysis that contributed to an inferior EFS was a poor remission status prior to HSCT (HR, 8.30; 1.08-63.56; P = 0.041, 95% CI).

CONCLUSION

The results of T-cell replete haploidentical transplantation with Post-Cy GVHD prophylaxis in high-risk pediatric patients are promising. However, further research is needed to determine the factors that have affect HLA compatibility for predicting the success of haploidentical transplantations.

Population pharmacokinetics of treosulfan in paediatric patients undergoing hematopoietic stem cell transplantation

Aims

Treosulfan is an alkylating agent increasingly used prior to haematopoietic stem cell transplantation. The aim of this study was to develop a population pharmacokinetic (PK) model of treosulfan in paediatric haematopoietic stem cell transplantation recipients and to explore the effect of potential covariates on treosulfan PK. Also, a limited sampling model (LSM) will be developed to accurately predict treosulfan exposure suitable for a therapeutic drug monitoring setting.

Methods

In this multicentre study, 91 patients, receiving a total dose of 30, 36 or 42 g/m² treosulfan, administered over 3 consecutive days, were enrolled. A population PK model was developed and demographic factors, as well as laboratory parameters, were included as potential covariates. In addition, a LSM was developed using data from 28 patients.

Results

A 2‐compartment model with first order elimination best described the data. Bodyweight with allometric scaling and maturation function were identified as significant predictors of treosulfan clearance. Treosulfan clearance reaches 90% of adult values at 4 postnatal years. A model‐based dosing table is presented to target an exposure of 1650 mg*h/L (population median) for different weight and age groups. Samples taken at 1.5, 4 and 7 hours after start of infusion resulted in the best limited sampling strategy.

Conclusions

This study provides a treosulfan population PK model in children and captures the developmental changes in clearance. A 3‐point LSM allows for accurate and precise estimation of treosulfan exposure.

A Single-Center Experience With Hematopoietic Stem Cell Transplantation for Pediatric Acute Lymphoblastic Leukemia: A Modest Pitch for Non-Total Body Irradiation Conditioning Regimens

OBJECTIVES

Allogeneic hematopoietic stem cell transplantation has been used for several decades to treat patients with acute lymphoblastic leukemia. Total body irradiation has been promoted as an important component of conditioning regimens for this process; however, recent reports of chemotherapy-based conditioning regimens have shown comparable outcomes.

MATERIALS AND METHODS

We report our experience with radiation-free conditioning using busulfan and cyclophosphamide in 127 pediatric patients with acute lymphoblastic leukemia who were treated between 1997 and 2014. The median age was 11 years (range, < 1 to 15 y), 70% of patients were male, 81.1% received transplants from HLA-matched siblings, 83% received peripheral blood stem cells, 41% were in second complete remission at the time of transplant, and 83% had B-lineage immunophenotype.

RESULTS

In patients who were in complete remission at the time of transplant, 5-year overall survival, leukemia-free survival, and relapse rates were 62.48% (95% confidence interval, 52.29-71.09%), 49.43% (95% confidence interval, 39.57-58.53%), and 45.64% (95% confidence interval, 35.85-54.88%), respectively. We observed significant differences between outcomes in patients by time of transplant, presence of chronic graft-versus-host disease, and remission status.

CONCLUSIONS

Our relapse rates were comparable to those shown in recent studies, although the transplant-related mortality rate was lower. The results of our study showed that a busulfan/cyclophosphamide conditioning regimen has acceptable outcomes without the undesirable adverse effects of total body irradiation, particularly in pediatric patients. Large multicenter studies are needed to assess less toxic conditioning regimens with fewer adverse effects in these patients.

An investigation on the predominant diseases, its diagnosis, and commonly used drugs in the poultry farms in the North-Eastern regions of Algeria

Aim

An investigation was carried out to assess the occurrence of diseases, its method of diagnosis, and commonly used drugs in poultry farms in North-Eastern regions of Algeria.

Materials and Methods

A total of 265 veterinary doctors were surveyed to obtain information on the dominant diseases, its frequency of occurrence, method of diagnosis, and commonly used drugs in poultry farms.

Results

A study revealed that about 68% of bacterial diseases are due to colibacillosis, mycoplasmosis, and salmonellosis, 22% of viral diseases are due to Newcastle, Gumboro, and infectious bronchitis, and 10% others including coccidiosis and ascites syndrome. The study also showed that about 57% of cases were diagnosed by clinical signs, 36% by necropsy findings, and the remaining 7% through therapeutic and laboratory analysis. Antibiotics, a predominance of the anarchic veterinary drugs, were massively used to control the diseases. Hence, there is a need for strict regulations on the use of veterinary drugs to guarantee food safety.

Conclusion

These results remain non-exhaustive but contribute strongly to determine the status of health of the birds in the region.

Treosulfan and Fludarabine Conditioning for Hematopoietic Stem Cell Transplantation in Children with Primary Immunodeficiency: UK Experience

We previously published results for 70 children who received conditioning with treosulfan and cyclophosphamide (n = 30) or fludarabine (n = 40) before undergoing hematopoietic stem cell transplantation (HSCT) for primary immunodeficiency (PID). Toxicity was lower and T cell chimerism was better in the patients receiving fludarabine, but cohort numbers were relatively small and follow-up was short. Here we report outcomes of 160 children who received homogeneous conditioning with treosulfan, fludarabine, and, in most cases, alemtuzumab (n = 124). The median age at transplantation was 1.36 years (range, .09 to 18.25 years). Donors included 73 matched unrelated, 54 1 to 3 antigen-mismatched unrelated, 12 matched sibling, 17 other matched family, and 4 haploidentical donors. Stem cell source was peripheral blood stem cells (PBSCs) in 70, bone marrow in 49, and cord blood in 41. Median duration of follow-up was 4.3 years (range, .8 to 9.4 years). Overall survival was 83%. No patients had veno-occlusive disease. Seventy-four patients (46%) had acute GVHD, but only 14 (9%) greater than grade II. Four patients underwent successful retransplantation for graft loss or poor immune reconstitution. Another patient experienced graft rejection and died. There was no association between T cell chimerism >95% and stem cell source, but a significant association was seen between myeloid chimerism >95% and use of PBSCs without an increased risk of significant GVHD compared with other sources. All 11 patients with severe combined immunodeficiency diagnosed at birth were alive at up to 8.7 years of follow-up. Long-term studies are needed to determine late gonadotoxic effects, and pharmacokinetic studies are needed to identify whether specific targeting is advantageous. The combination of treosulfan, fludarabine, and alemtuzumab is associated with excellent results in HSCT for PID.

Treosulfan-Based Conditioning Regimen in Sibling and Alternative Donor Hematopoietic Stem Cell Transplantation for Children with Sickle Cell Disease

BACKGROUND AND OBJECTIVES

Lack of suitable donors and regimen related toxicity are major barriers for hematopoietic stem cell transplantation (HSCT) in patients with sickle cell disease (SCD). The aim of the study is the assessment of efficacy and toxicity of Treosulfan-based conditioning regimen for SCD also when alternative donors such as mismatched unrelated donor and haploidentical donor are employed.

METHODS

We report our single-center experience: 11 patients with SCD received HSCT with a Treosulfan/Thiotepa/Fludarabine/Anti-thymoglobulin conditioning regimen between 2010 and 2015. The donor was a matched sibling donor (n= 7), a haploidentical parent (n= 2), a matched unrelated donor (n= 1) or a mismatched unrelated donor (n=1). The haploidentical and mismatched unrelated donor grafts were manipulated by removing TCRαβ and CD19 positive cells.

RESULTS

All patients survived the procedure and achieved stable engraftment. Stable mixed chimerism was observed in 5/11 patients. Grade III-IV regimen related toxicity was limited to mucositis and no grade III-IV graft-versus-host disease (GvHD) occurred. No SCD manifestation was observed post transplant and cerebral vasculopathy improved in 3/5 evaluable patients. Organ function evaluation showed no pulmonary, cardiac or renal toxicity but gonadal failure occurred in 1/4 evaluable patients.

CONCLUSION

Our data suggest that Treosulfan is associated with low toxicity and may be employed also for unrelated and haploidentical donor HSCT.

Factors Determining the Outcome of Hematopoietic Stem Cell Transplantation in Patients With Acute Lymphoblastic Leukemia at King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia

Medical records of 82 patients with acute lymphoblastic leukemia (ALL) who underwent hematopoietic cell transplantation (HCT) at our institution from 2005 to 2011 were reviewed. Forty-five patients were male (54.8%). The median age at HCT was 7.46 years (range, 0.98 to 14.31 y), the median time to HCT after diagnosis was 12.56 months. Ten patients were below the age of 1 year (12%). All patients were in complete remission at the time of HCT. In 83 transplants, 64 patients received HCT from human leukocyte antigen-identical-related donors and 19 from other donors. Stem cell source was bone marrow in 65 (78%) and cord blood in 18 (22%). Five-year overall survival was 58.8% and event-free survival was 54.3%. The cumulative incidence of acute graft versus host disease was 4.8%±2.3% and of chronic graft versus host disease was 8.9%±3.2%. The median time to absolute neutrophil count and platelet recovery was 17 days (range, 12 to 43 d) and 28 days (range, 15 to 98 d), respectively. One patient acquired CMV infection after transplant. No one developed venoocclusive disease, hemorrhagic cystitis, or other complication. Patient's age at diagnosis, sex, donor's human leukocyte antigen status and sex, source of transplant and complete remission status at HCT did not affect overall survival and event-free survival. Our results show a favorable outcome to HCT for acute lymphoblastic leukemia patients comparable to published data, and no single factor was associated with superior outcome.

A phase III, open label, randomized multicenter controlled trial of oral versus intravenous treosulfan in heavily pretreated recurrent ovarian cancer: a study of the North-Eastern German Society of Gynecological Oncology (NOGGO)

OBJECTIVE

In recurrent ovarian cancer (ROC), there is a high demand on effective therapies with a mild toxicity profile. Treosulfan is an alkylating agent approved as oral (p.o.) and intravenous (i.v.) formulation for the treatment of recurrent ovarian cancer. Data on safety and efficacy for either formulation are rare. For the first time we conducted a randomized phase III study comparing both formulations in women with ROC.

METHODS

Patients having received at least two previous lines of chemotherapy were randomly assigned to one of two treatment arms: treosulfan i.v. 7000 mg/m² d1 q4w or treosulfan p.o. 600 mg/m² d1-28 q8w. Primary endpoint was safety regarding hematological and gastrointestinal toxicity grade III/IV, secondary endpoints were other toxicities, clinical benefit rate (CBR), time to progression (TTP), overall survival (OS) and quality of life.

RESULTS

250 patients were treated with treosulfan i.v. (128) or treosulfan p.o. (122). In general treosulfan therapy was well tolerated in both treatment arms. Leukopenia grade III/IV occurred significantly more frequently in the p.o. arm (3.9% i.v. arm, 14.8% p.o. arm, p = 0.002). Other toxicities were similar in both arms. CBR was comparable between arms (41.4% i.v. arm, 36.9% p.o. arm). No difference in TTP (3.7 months i.v. arm, 3.5 months p.o. arm) or OS (13.6 months i.v. arm, 10.4 months p.o. arm, p = 0.087) occurred.

CONCLUSIONS

Given the safety and efficacy results treosulfan is an acceptable option for heavily pretreated OC patients. Regarding the toxicity profile the i.v. application was better tolerated with less grade III and IV toxicities.

Ocular disposition of treosulfan and its active epoxy-transformers following intravenous administration in rabbits

Treosulfan (TREO) has an established position in chemotherapy of advanced ovarian cancer but has been also applied in uveal melanoma patients. Moreover, it is used as an orphan drug for a myeloablative conditioning prior to stem cell transplantation. In this paper, biodistribution of prodrug TREO and its active monoepoxide (S,S-EBDM) and diepoxide (S,S-DEB) into aqueous humor of the eye was studied for the first time. For that purpose, alone TREO and the mixture of TREO, S,S-EBDM and S,S-DEB were administered intravenously to New Zealand White rabbits. The three analytes were determined in plasma and aqueous humor by validated HPLC methods and pharmacokinetic calculations were performed in WinNonlin. After the infusion of TREO, the aqueous humor/plasma C_max ratio and area under the curve ratio amounted 0.04 and 0.10 for TREO, and 1.1 and 2.2 for S,S-EBDM, respectively. Following the bolus injection of the mixture of the prodrug and its epoxides, the aqueous humor/plasma C_max ratios for TREO, S,S-EBDM and S,S-DEB were 0.05, 0.66, and 4.0, respectively. The presented results indicate a poor penetration of TREO into the eye, which may impair systemic treatment of ocular tumors but is beneficial in terms of a lack of clinically relevant ophthalmic adverse effects.

Treosulfan-based conditioning for allogeneic HSCT in children with chronic granulomatous disease: a multicenter experience

Chronic granulomatous disease (CGD) can be cured by allogeneic hemopoietic stem cell transplantation (HSCT). Complications include graft failure, graft-versus-host disease (GVHD), infection, and transplant-related mortality; therefore, reduced-intensity conditioning regimens are being used to improve outcomes. In this retrospective study, the aim was to determine the outcome of treosulfan-based conditioning in HSCT for pediatric patients with CGD. The following data were collected: risk features pre-HSCT, additional conditioning agents, donor type and stem cell source, toxicity, engraftment, GVHD, chimerism, viral reactivation, post-HSCT complications, length of follow-up, and outcome. Seventy patients (median age, 107 months; interquartile range [IQR], 46-232 months) from 16 centers worldwide were transplanted between 2006 and 2015. Ninety-one percent had high-risk features. Fifty-seven HLA-matched donors, 12 HLA-mismatched donors, and 1 CD3(+)TCR αβ/CD19 depleted parental haploidentical transplants were performed. No major toxicity was reported. Median times to neutrophil and platelet engraftment were 17 (IQR, 15-35) and 16 (IQR, 13-50) days. At a median follow-up of 34 months (IQR, 13-102 months), the overall survival was 91.4%, and event-free survival was 81.4%. The cumulative incidence of acute grade III-IV GVHD was 12%. Nine patients developed chronic GVHD. When split cell chimerism was available, 95% or more myeloid donor chimerism was documented in 80% of surviving patients. Secondary graft failure occurred in 12% of patients. Treosulfan-containing conditioning regimens can be used safely in HSCT for children with CGD and high-risk clinical features, achieving excellent survival with high myeloid chimerism. Further studies are needed to compare with other regimens and evaluate the long-term outcome, particularly on fertility.

Neonatal cellular and gene therapies for mucopolysaccharidoses: the earlier the better?

Mucopolysaccharidoses (MPSs) are a group of lysosomal storage disorders (LSDs). The increasing interest in newborn screening procedures for LSDs underlines the need for alternative cellular and gene therapy approaches to be developed during the perinatal period, supporting the treatment of MPS patients before the onset of clinical signs and symptoms. The rationale for considering these early therapies results from the clinical experience in the treatment of MPSs and other genetic disorders. The normal or gene-corrected hematopoiesis transplanted in patients can produce the missing protein at levels sufficient to improve and/or halt the disease-related abnormalities. However, these current therapies are only partially successful, probably due to the limited efficacy of the protein provided through the hematopoiesis. An alternative explanation is that the time at which the cellular or gene therapy procedures are performed could be too late to prevent pre-existing or progressive organ damage. Considering these aspects, in the last several years, novel cellular and gene therapy approaches have been tested in different animal models at birth, a highly early stage, showing that precocious treatment is critical to prevent long-term pathological consequences. This review provides insights into the state-of-art accomplishments made with neonatal cellular and gene-based therapies and the major barriers that need to be overcome before they can be implemented in the medical community.

European Society for Blood and Marrow Transplantation Analysis of Treosulfan Conditioning Before Hematopoietic Stem Cell Transplantation in Children and Adolescents With Hematological Malignancies

BACKGROUND

Standard myeloablative conditioning regimens for children with hematological malignancies undergoing allogeneic HSCT are based mainly on total body irradiation or busulfan. Their serious short- and long-term side effects warranted the exploration of less toxic alternatives. Treosulfan is increasingly used for adults and children before HSCT due to its potent immunosuppressive and cytotoxic effects combined with low organ toxicity.

PROCEDURE

To further investigate the role of treosulfan conditioning in children, the EBMT Pediatric diseases working party performed a retrospective analysis of 193 children with hematological malignancies (ALL n = 71, AML n = 47, MDS/MPS n = 40, other leukemia/lymphoma n = 25) undergoing allogeneic HSCT following treosulfan between January 2005 and July 2010.

RESULTS

Early regimen-related toxicity was low and mainly gastrointestinal. Veno-occlusive disease and neurological toxicity were rare. There was no association of toxicity with type of disease or treosulfan dose. High-grade early toxicity was not higher in infants or patients undergoing second or later transplantation. Treatment related mortality was low at 14%. Three-year event-free survival was 45 ± 4% and not significantly influenced by number of transplants, however it appeared to be significantly better for infants (P = 0.022). When compared to treosulfan plus fludarabine, the combination of treosulfan, fludarabine and an alkylator (either thiotepa or melphalan) resulted in significantly better overall survival (OS, P = 0.048) and a trend toward better EFS.

CONCLUSIONS

Treosulfan based conditioning is a safe and effective approach for children with hematological malignancies, including and importantly for infants and those patients undergoing second or later transplantation.

Penetration of Treosulfan and its Active Monoepoxide Transformation Product into Central Nervous System of Juvenile and Young Adult Rats

Treosulfan (TREO) is currently investigated as an alternative treatment of busulfan in conditioning before hematopoietic stem cell transplantation. The knowledge of the blood-brain barrier penetration of the drug is still scarce. In this paper, penetration of TREO and its active monoepoxide (S,S-EBDM) and diepoxide (S,S-DEB) into the CNS was studied in juvenile (JR) and young adult rats (YAR) for the first time. CD rats of both sexes (n = 96) received an intravenous dose of TREO 500 mg/kg b.wt. Concentrations of TREO, S,S-EBDM, and S,S-DEB in rat plasma, brain, and cerebrospinal fluid (CSF, in YAR only) were determined by validated bioanalytical methods. Pharmacokinetic calculations were performed in WinNonlin using a noncompartmental analysis and statistical evaluation was done in Statistica software. In male JR, female JR, male YAR, and female YAR, the brain/plasma area under the curve (AUC) ratio for unbound TREO was 0.14, 0.17, 0.10, and 0.07 and for unbound S,S-EBDM, it was 0.52, 0.48, 0.28, and 0.22, respectively. The CSF/plasma AUC ratio in male and female YAR was 0.12 and 0.11 for TREO and 0.66 and 0.64 for S,S-EBDM, respectively. Elimination rate constants of TREO and S,S-EBDM in all the matrices were sex-independent with a tendency to be lower in the JR. No quantifiable levels of S,S-DEB were found in the studied samples. TREO and S,S-EBDM demonstrated poor and sex-independent penetration into CNS. However, the brain exposure was greater in juvenile rats, so very young children might potentially be more susceptible to high-dose TREO-related CNS exposure than young adults.

Treosulfan-based conditioning regimens for allogeneic haematopoietic stem cell transplantation in children with non-malignant diseases

An increasing number of children with non-malignant diseases can be cured by allogeneic haematopoietic stem cell transplantation (HSCT). Treosulfan (L-treitol-1,4-bis-methanesulfonate) is being used more frequently for conditioning, owing to its' lower toxicity profile compared with conventional myeloablative regimens. A retrospective analysis was performed of children registered in the EBMT database, who received treosulfan before HSCT between January 2005 and 2010, to identify possible dose-related toxicity and determine the incidence of engraftment, treatment-related mortality and overall survival (OS). Results from 316 transplants from 11 different countries are presented. Ninety-five (30%) were under 1 year of age at the time of transplant. OS was 83% and event-free survival was 76%; 3-year OS and event-free survival of infants below 1 year were 79% and 73%, respectively. No association was found with age at transplant, dose of treosulfan given, other agents used in combination with treosulfan, donor type, stem cell source, or second or subsequent transplant. In this report of the largest number of children to date receiving treosulfan for non-malignant diseases, treosulfan is shown to be a safe and effective agent even for those under 1 year of age at the time of transplant. Further prospective studies are needed using precisely defined protocols with pharmacokinetic monitoring and detailed chimerism analysis. In addition, long-term studies will be vital to determine long-term effects, for example, on fertility in comparison with other regimens.