Improved Outcome Following Busulfan-Based Conditioning in Children with Functional Neutrophil Disorders Undergoing Hematopoietic Stem Cell Transplant from HLA-Matched Donors.

Hematopoietic stem-cell transplantation (HSCT) is the only curative treatment for chronic granulomatous disease (CGD) and leukocyte-adhesion deficiency (LAD), but both diseases have high rates of graft failure in transplant and patients with these diseases are often referred to HSCT with significant comorbidity. The intensity of the conditioning regimen should be balanced between the need to ensure durable engraftment and to minimize toxicity when transplanting young children with infections and organ damage. We report on 26 children transplanted at our institution with CGD and LAD over 24 years. We found a higher incidence of graft failure in patients receiving treosulfan based conditioning for their first transplant. There was no effect of conditioning regimen on overall survival, as all 8 patients that proceeded to a second busulfan-based HSCT were salvaged. We recommend giving patients with CGD and LAD fully myeloablative conditioning with either a busulfan-based regimen or the combination of treosulfan, fludarabine, and thiotepa.

αß+ /CD19+ -depleted haploidentical stem cell transplantation for children with acute leukemia: Is there a protective effect of increased γδ+ T-cell content in the graft?

BACKGROUND: Haploidentical hematopoietic stem cell transplantation (HSCT) with depletion of αß+ T cells and CD19+ B cells has emerged as a viable alternative to traditional donors for treating acute leukemia in children. As the use of this innovative approach continues to grow and more experience is gained, it is essential to identify and comprehend the key factors that contribute to successful transplantation and improved outcomes. METHODS: We conducted a retrospective analysis of single-center data from 27 children with acute lymphoblastic leukemia and 11 children with acute myeloid leukemia who underwent haploidentical HSCT with depletion of αß+ T cells and CD19+ B cells between the years 2013 and 2020. RESULTS: Engraftment was successful in 34 out of 38 patients (90%). The 5-year overall survival and event-free survival rates were 51% and 42%, respectively. There were no cases of grade III-IV acute graft-versus-host disease, and only two patients developed chronic graft-versus-host disease. Patients with a higher content of γδ+ T cells in the graft demonstrated a longer event-free survival. CONCLUSIONS: αß+ /CD19+ -depleted haploidentical hematopoietic stem cell transplantation can offer long-term remission for children with acute leukemia with minimal graft-versus-host disease.

Parameters of long-term response with CD28-based CD19 chimaeric antigen receptor-modified T cells in children and young adults with B-acute lymphoblastic leukaemia.

CD28-based CD19 chimaeric antigen receptor-modified (CAR-)Tcells were recently FDA-approved for adult acute lymphoblastic leukaemia (ALL). We report long-term outcome of 37 children and young adults treated with autologous CD19 CAR-T cells. The complete remission rate was 86%, of which 71% were polymerase chain reaction (PCR) minimal residual disease (MRD)-negative, 14% were MRD-negative by flow cytometry, and 14% were PCR MRD-positive. 26 patients proceeded to subsequent haematopoietic stem cell transplant (HSCT). 11 patients had a CD19-postive relapse (eight post HSCT and three without) and one had a CD19-negative relapse. All relapse events occurred within two years from cell therapy. With a median follow-up of three years, the median event-free survival (EFS) is 17 months and the median overall survival (OS) is not reached. The three-year EFS is 41% and OS is 56%. Patients with >5% blasts in the bone marrow prior to lymphodepletion had an inferior EFS. All patients with a PCR MRD-positive result at day 28 had relapsed after CAR-T-cell therapy. A prior HSCT did not significantly affect outcome, but a consolidative transplant after achieving remission improved long-term results. Overall, prelymphodepletion disease burden and molecular MRD negativity following CAR-T cells are predictors of long-term outcome following CD19 CAR-T-cell therapy for ALL.

Feasibility of leukapheresis for CAR T-cell production in heavily pre-treated pediatric patients.

BACKGROUND: Autologous CD19 chimeric-antigen receptor (CAR) T-cells are an effective salvage therapy for patients with relapsed or refractory B cell malignancies. The essential first step in the production is the collection of mature lymphocytes through leukapheresis. It is a challenging procedure given the fact patients are heavily pretreated and the special considerations of pediatric apheresis. METHODS: We analyzed the data of leukapheresis outcome for CAR T production in a phase 1b/2 clinical trial enrolling 34 children, adolescents and young adults with relapsed or refractory B-cell malignancies. RESULTS: All patients underwent a single leukapheresis. Given a short production time for CAR T-cells, most patients received bridging therapy prior to apheresis. Leukapheresis was performed using peripheral venous access in the majority (82%) of patients, and the remainder required arterial line or central venous access. T-cell collection efficiency (CE) was variable with a median of 18%. No apheresis-related adverse events were noted, and all procedures were successful but two: one resulting in lower than target dose (1 × 106 CAR + cells/kg) and the other in failure of CAR T-cell production. CONCLUSIONS: Collection of sufficient T-cells in heavily pretreated pediatric patients via a single apheresis procedure is feasible even with relatively low T-cell CE.

Locally produced CD19 CAR T cells leading to clinical remissions in medullary and extramedullary relapsed acute lymphoblastic leukemia.

Autologous CD19 chimeric-antigen receptor (CAR) T cells demonstrated remarkable remission rates in relapsed and refractory acute lymphoblastic leukemia (R/R ALL). Here, we report results from a phase 1b/2 study of in-house produced CD19 CAR with a CD28 costimulatory domain. Twenty-one patients with R/R ALL were enrolled, and 20 infused. The median age was 11 years (range, 5-48). Patients had a median of 4 prior regimens, including blinatumomab in 6 and prior stem-cell transplantation in 10. In total 8 patients had extramedullary (EM) leukemic involvement, and prior to lymphodepletion and CAR 7 had active lesions, a group underrepresented in previous trials. In vivo expansion of CAR T cells was observed in 18 patients. In total 16 patients developed cytokine release syndrome, and 11 patients developed neurotoxicity, with no toxic deaths. All responding patients were referred to an allogeneic hematopoietic stem-cell transplantation. The remission rate was 90%, including resolution of all refractory EM sites. Four responding patients relapsed, 3 who had a PCR-MRD positive remission at 28 days following CAR-T cells and 1 patient 21 months after an MRD-negative response. The estimated 1-year event-free survival and overall survival are 73% and 90%, respectively. Patients with R/R EM ALL may also benefit from CAR-T cell therapy.

Comparison of two cytoreductive regimens for αß-T-cell-depleted haploidentical HSCT in pediatric malignancies: Improved engraftment and outcome with TBI-based regimen.

BACKGROUND: Graft manipulation using selective depletion of αß-T cells provides a source of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) enriched in effector cells. We report our experience implementing this haplo-HSCT for high-risk malignancies in pediatric patients focusing on the conditioning regimen. PROCEDURE: We performed a retrospective study of patients who underwent T-cell receptor αß-depleted haplo-HSCT for high-risk pediatric malignancies. RESULTS: Eighteen patients underwent haplo-HSCT using this method. The initial reduced-toxicity chemotherapy-based conditioning regimen was given to eight patients, and resulted in a high rate of graft rejections (six of eight patients). Thus, total body irradiation (TBI) based regimen was introduced in the following 10 patients and resulted in engraftment in all patients. Neutrophil and platelet engraftment were rapid (median time to engraft, 10 days and 12 days, respectively). Significant treatment-related complications for both cohorts were all due to graft failure in patients receiving chemotherapy-based conditioning, with a treatment-related mortality rate of 17%. None of the patients developed hepatic sinusoidal-obstruction syndrome, and no grade III-IV acute graft versus host disease (GVHD) was observed. The majority of patients were free of immunosuppression in the first 100 days post-HSCT, and only two patients developed chronic GVHD. The cumulative incidence of relapse was 39%. Compared to patients conditioned with chemotherapy, patients conditioned with TBI had superior actuarial overall survival (66% vs. 37%, P = 0.05) and event-free survival (61% vs. 33%, P = 0.04). CONCLUSIONS: A TBI-based conditioning for haplo-HSCT using αß-T-cell depletion for malignant diseases ensured engraftment and resulted in acceptable outcomes.

The metabolic syndrome and its components in pediatric survivors of allogeneic hematopoietic stem cell transplantation.

Metabolic syndrome (MetS) is a known complication after hematopoietic stem cell transplantations (HSCT) that contributes to long-term morbidity. We assessed the prevalence of components of the MetS in pediatric survivors of allogeneic HSCT and identified associated risk factors. Thirty-eight patients, median age at HSCT, 8.5 years, were evaluated at a median of 3.9 years post-HSCT. Overweight or obesity was seen in 23.7% of the patients, 15.8% had hypertension, 15.8% had hypertriglyceridemia, and 13% had low high-density lipoprotein cholesterol levels according to age and gender. Four (10.5%) met the criteria of MetS; all were transplanted for malignant disease. Twelve patients (31.6%) had at least one component of the MetS. The 5-year probability of developing components of the MetS revealed that patients with BMI-Z score ≥0 at HSCT were significantly at higher risk than those with lower BMI-Z. Patients who developed components of the MetS had higher levels of insulin, homeostasis model assessment, uric acid, leptin, and lower adiponectin levels. Multivariable regression analysis revealed that BMI-Z-score >1.036 at time of evaluation was associated with 4.3-fold increased risk (P=.050) and adiponectin levels ≤6 µg/mL were associated with 6.7-fold increased risk of develop components of the MetS (P=.007). Overweight and obesity and adiponectin levels may be useful as markers in HSCT survivors.

The role of immunoglobulin prophylaxis for prevention of cytomegalovirus infection in pediatric hematopoietic stem cell transplantation recipients.

BACKGROUND: Following cessation of intravenous immunoglobulin (IVIg) administration for allogeneic hematopoietic stem cell transplantation (HSCT) recipients at our unit, we observed a sharp decline in the incidence of cytomegalovirus (CMV) infection. PROCEDURE: We conducted a retrospective study of the role of IVIg in the prevention of CMV infection in children and young adults who underwent HSCT from matched related donor. RESULTS: We included 109 patients (IVIg+/IVIg- ratio 82/27). Median age was 8.5 years. Patients were transplanted for malignant (59.7%) and nonmalignant diseases (40.3%) with myeloablative, reduced-intensity, and nonmyeloablative conditioning in 76, 22, and 2% of the transplants, respectively. Graft sources were peripheral blood stem cells, bone marrow, and cord blood in 58.7, 39.4, and 2%, respectively. The cumulative incidence of CMV infection at 1 year after HSCT was significantly higher in the cohort that did not receive IVIg compared with the one that did (44.4% vs. 13.4%, respectively, P = 0.001). Significant risk factor for CMV infection in the cohort not receiving IVIg was conditioning with total body irradiation (TBI) (87.5% in TBI+ vs. 26.3% in TBI-, P = 0.003). CONCLUSIONS: We conclude that children and young adults who undergo HSCT with TBI may need a preemptive regimen of anti-CMV treatment, if they do not get IVIg prophylaxis.

Risk of complications during hematopoietic stem cell collection in pediatric sibling donors: a prospective European Group for Blood and Marrow Transplantation Pediatric Diseases Working Party study.

We investigated prospectively factors influencing the safety of hematopoietic stem cell (HSC) collection in 453 pediatric donors. The children in the study donated either BM or peripheral blood stem cells (PBSCs) according to center policy. A large variability in approach to donor issues was observed between the participating centers. Significant differences were observed between BM and PBSC donors regarding pain, blood allotransfusion, duration of hospital stay, and iron supplementation; however, differences between the groups undergoing BM vs PBSC donation preclude direct risk comparisons between the 2 procedures. The most common adverse event was pain, reported mainly by older children after BM harvest, but also observed after central venous catheter (CVC) placement for PBSC collection. With regard to severe adverse events, one patient (0.7%) developed a pneumothorax with hydrothorax after CVC placement for PBSC collection. The risk of allotransfusion after BM harvest was associated with a donor age of < 4 years and a BM harvest volume of > 20 mL/kg. Children < 4 years were at higher risk than older children for allotransfusion after BM harvest and there was a higher risk of complications from CVC placement before apheresis. We conclude that PBSC and BM collection are safe procedures in children.

The EBMT Immune Effector Cell Nursing Guidelines on CAR-T Therapy: A Framework for Patient Care and Managing Common Toxicities.

Chimeric antigen receptor T-cell (CAR T) therapy is a new and rapidly developing field. Centers across the world are gaining more experience using these innovative anti-cancer treatments, transitioning from the 'bench' to the 'bedside', giving benefit to an increasing number of patients. For those with some refractory hematological malignancies, CAR-T may offer a treatment option that was not available a few years ago.CAR-T therapy is an immune effector cell and precision/personalized medicine treatment which is tailored to the individual patient and associated with a variety of unique adverse events and toxicities that necessitate specialist nursing/medical vigilance in an appropriate clinical setting. Subtle unrecognized signs and symptoms can result in rapid deterioration and, possibly, life threatening cardiorespiratory and/or neurological sequelae.These guidelines have been prepared for nurses working in cellular therapy in inpatient, outpatient and ambulatory settings. Many nurses will encounter cellular therapy recipients indirectly, during the referral process, following discharge, and when patients are repatriated back to local centers. The aim of these guidelines is to provide all nurses with a practice framework to enable recognition, monitoring and grading of CAR-T therapy-associated toxicities, and to support and nurse these highly complex patients with confidence.They have been developed under the auspices of several bodies of the European society for Blood and Marrow Transplantation (EBMT), by experienced health professionals, and will be a valuable resource to all practitioners working in cellular therapy.

Safe transfer of pediatric patients from hematopoietic stem cell transplant unit into the pediatric intensive care unit: views of nurses and physicians.

Sufficient communication between hematopoietic stem cell transplantation (HSCT) and pediatric intensive care unit (PICU) teams is pivotal for a successful advanced support in the PICU for HSCT-related complications. We evaluated perceived communication and barriers between both teams with the aim of providing recommendations for improvement. In this cross-sectional survey, a self-designed online questionnaire was distributed among ESPNIC and EBMT members. Data were analyzed using descriptive statistics. Over half of HSCT respondents employed a transfer indication protocol and patient assessment tool, but less structured checklist prior to patient transfer. Nearly all PICU respondents perceived this checklist as improvement for communication. Most HSCT and PICU physicians have daily rounds upon patient transfer while this is mostly missing between nursing teams. Half of both HSCT and PICU nurses indicated that HSCT training for PICU nurses could improve communication and patient transfer. Most respondents indicated that structured meetings between HSCT and PICU nurses could improve communication. Overall there is good communication between HSCT and PICU units, although barriers were noted between members of both teams. Based on our findings, we recommend use of a structured and specific checklist by HSCT teams, HSCT training for PICU personnel, and structured meetings between HSCT and PICU nurses.

Specialized Pediatric Palliative Care Services in Pediatric Hematopoietic Stem Cell Transplant Centers.

Hematopoietic stem cell transplantation (HSCT) is widely used in pediatric patients as a successful curative therapy for life-threatening conditions. The treatment is intensive, with risks of serious complications and lethal outcomes. This study aimed to provide insight into current data on the place and cause of death of transplanted children, the available specialized pediatric palliative care services (SPPCS), and what services HSCT professionals feel the SPPCS team should provide. First, a retrospective database analysis on the place and cause of death of transplanted pediatric HSCT patients was performed. Second, a survey was performed addressing the availability of and views on SPPCS among HSCT professionals. Database analysis included 233 patients of whom the majority died in-hospital: 38% in the pediatric intensive care unit, 20% in HSCT units, 17% in other hospitals, and 14% at home or in a hospice (11% unknown). For the survey, 98 HSCT professionals from 54 centers participated. Nearly all professionals indicated that HSCT patients should have access to SPPCS, especially for pain management, but less than half routinely referred to this service at an early stage. We, therefore, advise HSCT teams to integrate advance care planning for pediatric HSCT patients actively, ideally from diagnosis, to ensure timely SPPCS involvement and maximize end-of-life preparation.

Contribution of nurses to protective environment in haematopoietic cell transplant setting: an international survey by the European Society for Blood and Marrow Transplantation.

Infections are frequently experienced complications for patients undergoing haematopoietic cell transplant (HCT). To assess current infection prevention strategies, an international survey among HCT nurses was conducted by the Nurses Group and IDWP of the EBMT. Nurse representatives from all EBMT transplant centres were invited to complete an online questionnaire on protective environment in adult and paediatric HCT units. A total of 141 complete questionnaires were returned for the isolation section and 26 for the paediatric section, the majority of respondents (89.4%) being nurses. A small number of centres (7.1%) reported not allowing visitors, the rest have rules for entering patient rooms. Most HCT units (99.3%) indicated that nurses play a critical role in infection prevention and measures differed between bacterial infections and viral infections. Many of the paediatric units (57.7%) had a play area, applying rules of entry. To our knowledge, this is the first survey on protective environment directed at nurses within HCT centres. Despite having different practices, most HCT units tend to decrease isolation procedures and the use of PPE for multi-drug resistant organisms. This must concur with an increase of hand hygiene compliance, for which our data show that there is still room for improvement.

Supportive Care During Pediatric Hematopoietic Stem Cell Transplantation: Prevention of Infections. A Report From Workshops on Supportive Care of the Paediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT).

Specific protocols define eligibility, conditioning, donor selection, graft composition and prophylaxis of graft vs. host disease for children and young adults undergoing hematopoietic stem cell transplant (HSCT). However, international protocols rarely, if ever, detail supportive care, including pharmaceutical infection prophylaxis, physical protection with face masks and cohort isolation or food restrictions. Supportive care suffers from a lack of scientific evidence and implementation of practices in the transplant centers brings extensive restrictions to the child's and family's daily life after HSCT. Therefore, the Board of the Pediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT) held a series of dedicated workshops since 2017 with the aim of initiating the production of a set of minimal recommendations. The present paper describes the consensus reached within the field of infection prophylaxis.

Correction: Supportive care during pediatric hematopoietic stem cell transplantation: beyond infectious diseases. A report from workshops on supportive care of the Pediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT).

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Supportive care during pediatric hematopoietic stem cell transplantation: beyond infectious diseases. A report from workshops on supportive care of the Pediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT).

Hematopoietic stem cell transplantation (HSCT) is currently the standard of care for many malignant and nonmalignant blood diseases. As several treatment-emerging acute toxicities are expected, optimal supportive measurements critically affect HSCT outcomes. The paucity of good clinical studies in supportive practices gives rise to the establishment of heterogeneous guidelines across the different centers, which hampers direct clinical comparison in multicentric studies. Aiming to harmonize the supportive care provided during the pediatric HSCT in Europe, the Pediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT) promoted dedicated workshops during the years 2017 and 2018. The present paper describes the resulting consensus on the management of sinusoidal obstructive syndrome, mucositis, enteral and parenteral nutrition, iron overload, and emesis during HSCT.

Immune reconstitution after HSCT in SCID-a cohort of conditioned and unconditioned patients.

Allogeneic hematopoietic stem cell transplantation (HSCT) is the effective mean of immune restoration in severe combined immunodefiency (SCID). Usually, HSCT without cytoreductive conditioning is attempted. Nevertheless, conditioning procedures are still preferred in a subset of patients. Herein, we describe the immunological outcome in a cohort of conditioned and unconditioned patients, from diagnosis, through transplantation, to follow-up. This retrospective study was conducted on 17 patients with SCID (10 conditioned, 7 unconditioned) who later underwent HSCT. Immune reconstitution was assessed in the post-transplant year by quantification of T cell receptor excision circles (TRECs) and kappa-deleting recombination excision circles (KRECs), among additional laboratory and clinical evaluations. Unconditioned patients were diagnosed and transplanted earlier. TREC and KREC quantification showed a gradual increase in both groups, with higher levels in the conditioned group. Engraftment percentages differed drastically between groups, favoring the conditioned group. Unconditioned patients were significantly more dependent on intravenous immunoglobulins (IVIGs). One patient from each group succumbed to disease complications. Conditioning demonstrated superior laboratorial outcomes. Patients with unique characteristics (i.e., consanguinity, Bacillus Calmette-Guérin vaccination, impaired access to IVIG) may require personalized considerations. The effort to implement secondary prevention of SCID with newborn screening should continue.

Haploidentical hematopoietic stem cell transplantation with αßTCR+/CD19+ depletion in pediatric patients with malignant and non-malignant disorders.

Haploidntical hematopoietic stem cell transplantation has been increasingly used in recent years for patients without a matched donor. The αßTCR+/CD19+ depletion technique provide a graft that is enriched with CD34 cells, γδ-T-cells and natural killer. The current experience with αßTCR+/CD19+ depleted grafts in pediatric patients with malignant and non-malignant disorders, demonstrated rapid engraftment, improved immune reconstitution and low risk of GVHD. Future studies will need to define the optimal conditioning regimen in order to improve transplant outcome.

The kinetics of early T and B cell immune recovery after bone marrow transplantation in RAG-2-deficient SCID patients.

The kinetics of T and B cell immune recovery after bone marrow transplantation (BMT) is affected by many pre- and post-transplant factors. Because of the profoundly depleted baseline T and B cell immunity in recombination activating gene 2 (RAG-2)-deficient severe combined immunodeficiency (SCID) patients, some of these factors are eliminated, and the immune recovery after BMT can then be clearly assessed. This process was followed in ten SCID patients in parallel to their associated transplant-related complications. Early peripheral presence of T and B cells was observed in 8 and 4 patients, respectively. The latter correlated with pre-transplant conditioning therapy. Cells from these patients carried mainly signal joint DNA episomes, indicative of newly derived B and T cells. They were present before the normalization of the T cell receptor (TCR) and the B cell receptor (BCR) repertoire. Early presentation of the ordered TCR gene rearrangements after BMT occurred simultaneously, but this pattern was heterogeneous over time, suggesting different and individual thymic recovery processes. Our findings early after transplant could suggest the long-term patients' clinical outcome. Early peripheral presence of newly produced B and T lymphocytes from their production and maturation sites after BMT suggests donor stem cell origin rather than peripheral expansion, and is indicative of successful outcome. Peripheral detection of TCR excision circles and kappa-deleting recombination excision circles in RAG-2-deficient SCID post-BMT are early markers of T and B cell reconstitution, and can be used to monitor outcome and tailor specific therapy for patients undergoing BMT.