Hematologic Cancer after Gene Therapy for Cerebral Adrenoleukodystrophy.

BACKGROUND: Gene therapy with elivaldogene autotemcel (eli-cel) consisting of autologous CD34+ cells transduced with lentiviral vector containing ABCD1 complementary DNA (Lenti-D) has shown efficacy in clinical studies for the treatment of cerebral adrenoleukodystrophy. However, the risk of oncogenesis with eli-cel is unclear. METHODS: We performed integration-site analysis, genetic studies, flow cytometry, and morphologic studies in peripheral-blood and bone marrow samples from patients who received eli-cel therapy in two completed phase 2-3 studies (ALD-102 and ALD-104) and an ongoing follow-up study (LTF-304) involving the patients in both ALD-102 and ALD-104. RESULTS: Hematologic cancer developed in 7 of 67 patients after the receipt of eli-cel (1 of 32 patients in the ALD-102 study and 6 of 35 patients in the ALD-104 study): myelodysplastic syndrome (MDS) with unilineage dysplasia in 2 patients at 14 and 26 months; MDS with excess blasts in 3 patients at 28, 42, and 92 months; MDS in 1 patient at 36 months; and acute myeloid leukemia (AML) in 1 patient at 57 months. In the 6 patients with available data, predominant clones contained lentiviral vector insertions at multiple loci, including at either MECOM-EVI1 (MDS and EVI1 complex protein EVI1 [ecotropic virus integration site 1], in 5 patients) or PRDM16 (positive regulatory domain zinc finger protein 16, in 1 patient). Several patients had cytopenias, and most had vector insertions in multiple genes within the same clone; 6 of the 7 patients also had somatic mutations (KRAS, NRAS, WT1, CDKN2A or CDKN2B, or RUNX1), and 1 of the 7 patients had monosomy 7. Of the 5 patients with MDS with excess blasts or MDS with unilineage dysplasia who underwent allogeneic hematopoietic stem-cell transplantation (HSCT), 4 patients remain free of MDS without recurrence of symptoms of cerebral adrenoleukodystrophy, and 1 patient died from presumed graft-versus-host disease 20 months after HSCT (49 months after receiving eli-cel). The patient with AML is alive and had full donor chimerism after HSCT; the patient with the most recent case of MDS is alive and awaiting HSCT. CONCLUSIONS: Hematologic cancer developed in a subgroup of patients who were treated with eli-cel; the cases are associated with clonal vector insertions within oncogenes and clonal evolution with acquisition of somatic genetic defects. (Funded by Bluebird Bio; ALD-102, ALD-104, and LTF-304 ClinicalTrials.gov numbers, NCT01896102, NCT03852498, and NCT02698579, respectively.).

Lentiviral Gene Therapy for Cerebral Adrenoleukodystrophy.

BACKGROUND: Cerebral adrenoleukodystrophy is a severe form of X-linked adrenoleukodystrophy characterized by white-matter disease, loss of neurologic function, and early death. Elivaldogene autotemcel (eli-cel) gene therapy, which consists of autologous CD34+ cells transduced with Lenti-D lentiviral vector containing ABCD1 complementary DNA, is being tested in persons with cerebral adrenoleukodystrophy. METHODS: In a phase 2-3 study, we evaluated the efficacy and safety of eli-cel therapy in boys with early-stage cerebral adrenoleukodystrophy and evidence of active inflammation on magnetic resonance imaging (MRI). The primary efficacy end point was survival without any of six major functional disabilities at month 24. The secondary end points included overall survival at month 24 and the change from baseline to month 24 in the total neurologic function score. RESULTS: A total of 32 patients received eli-cel; 29 patients (91%) completed the 24-month study and are being monitored in the long-term follow-up study. At month 24, none of these 29 patients had major functional disabilities; overall survival was 94%. At the most recent assessment (median follow-up, 6 years), the neurologic function score was stable as compared with the baseline score in 30 of 32 patients (94%); 26 patients (81%) had no major functional disabilities. Four patients had adverse events that were directly related to eli-cel. Myelodysplastic syndrome (MDS) with excess blasts developed in 1 patient at month 92; the patient underwent allogeneic hematopoietic stem-cell transplantation and did not have MDS at the most recent follow-up. CONCLUSIONS: At a median follow-up of 6 years after lentiviral gene therapy, most patients with early cerebral adrenoleukodystrophy and MRI abnormalities had no major functional disabilities. However, insertional oncogenesis is an ongoing risk associated with the integration of viral vectors. (Funded by Bluebird Bio; ALD-102 and LTF-304 ClinicalTrials.gov numbers NCT01896102 and NCT02698579, respectively.).

Higher abatacept exposure after transplant decreases acute GVHD risk without increasing adverse events.

In the ABA2 study, the T-cell costimulation blockade agent, abatacept, was safe and effective in preventing acute graft-versus-host disease (aGVHD) after unrelated-donor hematopoietic cell transplant (HCT), leading to US Food and Drug Administration approval. Here, we performed a determination of abatacept pharmacokinetics (PK), which enabled an examination of how abatacept exposure-response relationships affected clinical outcomes. We performed a population PK analysis of IV abatacept using nonlinear mixed-effect modeling and assessed the association between abatacept exposure and key transplant outcomes. We tested the association between the trough after dose 1 (Ctrough_1) and grade (GR) 2 or 4 aGVHD (GR2-4 aGVHD) through day +100. An optimal Ctrough_1 threshold was identified via recursive partitioning and classification tree analysis. This demonstrated that abatacept PK was characterized by a 2-compartment model with first-order elimination. The ABA2 dosing regimen was based on previous work targeting a steady-state abatacept trough of 10 µg/mL. However, a higher Ctrough_1 (≥39 µg/mL, attained in ∼60% of patients on ABA2) was associated with a favorable GR2-4 aGVHD risk (hazard ratio, 0.35; 95% confidence interval, 0.19-0.65; P < .001), with a Ctrough_1 <39 µg/mL associated with GR2-4 aGVHD risk indistinguishable from placebo (P = .37). Importantly, no significant association was found between Ctrough_1 and key safety indicators, including relapse, and cytomegalovirus or Epstein-Barr virus viremia. These data demonstrate that a higher abatacept Ctrough_1 (≥39 µg/mL) was associated with a favorable GR2-4 aGVHD risk, without any observed exposure-toxicity relationships. This trial was registered at www.clinicaltrials.gov as #NCT01743131.

Outcomes for Pediatric Oncology and Hematopoietic Stem Cell Transplantation Patients Who Undergo Tracheostomy Placement: A Pediatric Health Information System Database Cohort Study, 2009-2020.

OBJECTIVES: To describe the epidemiology, surgical complications, and long-term outcomes after tracheostomy in pediatric oncology and/or hematopoietic stem cell transplantation (HSCT) patients in U.S. Children's Hospitals. DESIGN: Retrospective cohort from the Pediatric Health information System (PHIS) database, 2009-2020. SETTING: The PHIS dataset incorporates data from 48 pediatric hospitals in the Children's Hospital Association. PATIENTS: Patients 0-21 years old with an oncologic diagnosis and/or underwent HSCT, received a tracheostomy, and were discharged from hospital between January 1, 2009, and December 31, 2020. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: There were 1061 patients included in the dataset, and 217 (20.5%) had undergone HSCT. The annual prevalence in tracheostomy usage did not change over the study period. The majority of patients (62.2%) underwent tracheostomy early (< 30 d) in the admission and those who underwent the procedure later (> 90 d) had a significant increase in mortality (52.6% vs. 17.6%; p < 0.001) and mechanical ventilation (MV) at discharge (51.9% vs. 24.5%; p < 0.001) compared with the early tracheostomy patients. Complications reported included tracheostomy site bleeding (< 1%) and infection (24%). The overall rate of MV at discharge was 32.6% and significantly associated with chronic lung (adjusted odds ratio [OR], 1.54; 95% CI, 1.03-2.32) and acute lung disease (OR, 2.18; 95% CI, 1.19-3.98). The overall rate of mortality was 19.6% within the cohort and significantly associated with HSCT (OR, 5.45; 95% CI, 3.88-7.70), diagnosis of sepsis (OR, 2.09; 95% CI, 1.28-3.41), and requirement for renal replacement therapy (OR, 2.76; 95% CI, 1.58-4,83). CONCLUSIONS: This study demonstrated a static prevalence of tracheostomy placement in the cohort population relative to the increasing trends in other reported groups. Regardless of underlying diagnosis, the study patients incurred substantial morbidity and mortality. However, tracheostomy specific complication rates were comparable with that of the general pediatric population and were not associated with increased odds of mortality within this population.

Characterization of orofacial features in sclerodermatous chronic graft-versus-host disease.

BACKGROUND: Chronic graft-versus-host disease (cGVHD) is a leading cause of morbidity and mortality following allogeneic hematopoietic cell transplantation (alloHCT). The sclerodermatous form of cGVHD can be particularly debilitating; however, orofacial sclerodermatous involvement remains poorly described. OBJECTIVE: To characterize orofacial features of sclerodermatous cGVHD in a single center cohort of patients who underwent alloHCT. STUDY DESIGN: Retrospective data were collected from electronic medical records and analyzed descriptively. RESULTS: There were 39 patients who received alloHCT between 1993 and 2017 and developed orofacial sclerodermatous cGVHD. Concomitant cutaneous sclerodermatous cGVHD was common (n = 20, 51%). Orofacial sclerodermatous cGVHD features included fibrous bands of the buccal mucosa (n = 23, 59%), limited mouth opening (n = 19, 54%), perioral fibrosis (n = 8, 21%), and focal gingival recession (n = 4, 10%). Oral mucosal fibrosis was observed at the site of active or resolved chronic lichenoid inflammation in 30 patients, with all but two also presenting with a history of ulcerations. Management included jaw stretching exercises (n = 10; 6 stable/improved), surgery (n = 3; 2 improved), and intralesional corticosteroid injections (n = 2; 2 improved). CONCLUSIONS: Orofacial involvement with sclerodermatous cGVHD can present with multiple manifestations including fibrous banding, limited mouth opening, perioral fibrosis, and focal gingival recession. Surgical and non-surgical management strategies may improve clinical function and reduce morbidity.

Neighborhood poverty and pediatric allogeneic hematopoietic cell transplantation outcomes: a CIBMTR analysis.

Social determinants of health, including poverty, contribute significantly to health outcomes in the United States; however, their impact on pediatric hematopoietic cell transplantation (HCT) outcomes is poorly understood. We aimed to identify the association between neighborhood poverty and HCT outcomes for pediatric allogeneic HCT recipients in the Center for International Blood and Marrow Transplant Research database. We assembled 2 pediatric cohorts undergoing first allogeneic HCT from 2006 to 2015 at age ≤18 years, including 2053 children with malignant disease and 1696 children with nonmalignant disease. Neighborhood poverty exposure was defined a priori per the US Census definition as living in a high-poverty ZIP code (≥20% of persons below 100% federal poverty level) and used as the primary predictor in all analyses. Our primary outcome was overall survival (OS), defined as the time from HCT until death resulting from any cause. Secondary outcomes included relapse and transplantation-related mortality (TRM) in malignant disease, acute and chronic graft-versus-host disease, and infection in the first 100 days post-HCT. Among children undergoing transplantation for nonmalignant disease, neighborhood poverty was not associated with any HCT outcome. Among children undergoing transplantation for malignant disease, neighborhood poverty conferred an increased risk of TRM but was not associated with inferior OS or any other transplantation outcome. Among children with malignant disease, a key secondary finding was that children with Medicaid insurance experienced inferior OS and increased TRM compared with those with private insurance. These data suggest opportunities for future investigation of the effects of household-level poverty exposure on HCT outcomes in pediatric malignant disease to inform care delivery interventions.

Interprofessional Team-based Care of the Hematopoietic Cell Transplantation Patient With Hepatic Veno-occlusive Disease/Sinusoidal Obstruction Syndrome.

Hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a well-recognized complication of allogeneic and autologous hematopoietic cell transplantation (HCT). The diagnosis and treatment of VOD/SOS require the involvement of multiple specialists covering a wide range of expertise. Interprofessional team-based medical care is standard practice for patients undergoing HCT and has been shown to improve patient and provider satisfaction, enhance efficiency, and improve patient outcomes, particularly for patients in complex medical situations like those with VOD/SOS post-HCT. Interdisciplinary team-based models focus on the synthesis and harmonization of knowledge and methods from different disciplines to create an integrative approach to patient care that both maximizes the expertise of each involved specialist and encourages thought beyond each specialist's discipline. Multidisciplinary team members provide additive support and work collaboratively with the core team to provide knowledge from their field. The composition of the interdisciplinary HCT team should center on the needs of the patient and institutional resources and involve the expertise of additional multidisciplinary team members based on clinical needs. This review focuses on interdisciplinary and multidisciplinary team-based care of patients with VOD/SOS post-HCT and provides an example of a collaborative VOD/SOS team that includes transplant physicians, nurses, pharmacists, nutrition/dietary specialists, and intensive care teams.

Comparison of hematopoietic cell transplant conditioning regimens for hemophagocytic lymphohistiocytosis disorders.

BACKGROUND: Allogeneic hematopoietic cell transplantation for hemophagocytic lymphohistiocytosis (HLH) disorders is associated with substantial morbidity and mortality. OBJECTIVE: The effect of conditioning regimen groups of varying intensity on outcomes after transplantation was examined to identify an optimal regimen or regimens for HLH disorders. METHODS: We studied 261 patients with HLH disorders transplanted between 2005 and 2018. Risk factors for transplantation outcomes by conditioning regimen groups were studied by Cox regression models. RESULTS: Four regimen groups were studied: (1) fludarabine (Flu) and melphalan (Mel) in 123 subjects; (2) Flu, Mel, and thiotepa (TT) in 28 subjects; (3) Flu and busulfan (Bu) in 14 subjects; and (4) Bu and cyclophosphamide (Cy) in 96 subjects. The day 100 incidence of veno-occlusive disease was lower with Flu/Mel (4%) and Flu/Mel/TT (0%) compared to Flu/Bu (14%) and Bu/Cy (22%) (P < .001). The 6-month incidence of viral infections was highest after Flu/Mel (72%) and Flu/Mel/TT (64%) compared to Flu/Bu (39%) and Bu/Cy (38%) (P < .001). Five-year event-free survival (alive and engrafted without additional cell product administration) was lower with Flu/Mel (44%) compared to Flu/Mel/TT (70%), Flu/Bu (79%), and Bu/Cy (61%) (P = .002). The corresponding 5-year overall survival values were 68%, 75%, 86%, and 64%, and did not differ by conditioning regimen (P = .19). Low event-free survival with Flu/Mel is attributed to high graft failure (42%) compared to Flu/Mel/TT (15%), Flu/Bu (7%), and Bu/Cy (18%) (P < .001). CONCLUSIONS: Given the high rate of graft failure with Flu/Mel and the high rate of veno-occlusive disease with Bu/Cy and Flu/Bu, Flu/Mel/TT may be preferred for HLH disorders. Prospective studies are warranted.

Assessment of ST2 for risk of death following graft-versus-host disease in pediatric and adult age groups.

Assessment of prognostic biomarkers of nonrelapse mortality (NRM) after allogeneic hematopoietic cell transplantation (HCT) in the pediatric age group is lacking. To address this need, we conducted a prospective cohort study with 415 patients at 6 centers: 170 were children age 10 years or younger and 245 were patients older than age 10 years (both children and adults were accrued from 2013 to 2018). The following 4 plasma biomarkers were assessed pre-HCT and at days +7, +14, and +21 post-HCT: stimulation-2 (ST2), tumor necrosis factor receptor 1 (TNFR1), regenerating islet-derived protein 3α (REG3α), and interleukin-6 (IL-6). We performed landmark analyses for NRM, dichotomizing the cohort at age 10 years or younger and using each biomarker median as a cutoff for high- and low-risk groups. Post-HCT biomarker analysis showed that ST2 (>26 ng/mL), TNFR1 (>3441 pg/mL), and REG3α (>25 ng/mL) are associated with NRM in children age 10 years or younger (ST2: hazard ratio [HR], 9.13; 95% confidence interval [CI], 2.74-30.38; P = .0003; TNFR1: HR, 4.29; 95% CI, 1.48-12.48; P = .0073; REG3α: HR, 7.28; 95% CI, 2.05-25.93; P = .0022); and in children and adults older than age 10 years (ST2: HR, 2.60; 95% CI, 1.15-5.86; P = .021; TNFR1: HR, 2.09; 95% CI, 0.96-4.58; P = .06; and REG3α: HR, 2.57; 95% CI, 1.19-5.55; P = .016). When pre-HCT biomarkers were included, only ST2 remained significant in both cohorts. After adjustment for significant covariates (race/ethnicity, malignant disease, graft, and graft-versus-host-disease prophylaxis), ST2 remained associated with NRM only in recipients age 10 years or younger (HR, 4.82; 95% CI, 1.89-14.66; P = .0056). Assays of ST2, TNFR1, and REG3α in the first 3 weeks after HCT have prognostic value for NRM in both children and adults. The presence of ST2 before HCT is a prognostic biomarker for NRM in children age 10 years or younger allowing for additional stratification. This trial was registered at www.clinicaltrials.gov as #NCT02194439.

Candidacy for Extracorporeal Life Support in Children After Hematopoietic Cell Transplantation: A Position Paper From the Pediatric Acute Lung Injury and Sepsis Investigators Network's Hematopoietic Cell Transplant and Cancer Immunotherapy Subgroup.

OBJECTIVES: The last decade has seen improved outcomes for children requiring extracorporeal life support as well as for children undergoing hematopoietic cell transplantation. Thus, given the historically poor survival of hematopoietic cell transplantation patients using extracorporeal life support, the Pediatric Acute Lung Injury and Sepsis Investigators' hematopoietic cell transplantation and cancer immunotherapy subgroup aimed to characterize the utility of extracorporeal life support in facilitating recovery from critical cardiorespiratory illnesses in pediatric hematopoietic cell transplantation patients. DATA SOURCES: All available published data were identified using a set of PubMed search terms for pediatric extracorporeal life support and hematopoietic cell transplantation. STUDY SELECTION: All articles that provided original reports of pediatric hematopoietic cell transplantation patients who underwent extracorporeal life support were included. Sixty-four manuscripts met search criteria. Twenty-four were included as primary reports of pediatric hematopoietic cell transplantation patients who underwent extracorporeal life support (11 were single case reports, four single institution case series, two multi-institution case series, and seven registry reports from Extracorporeal Life Support Organization, Pediatric Heath Information System, and Virtual Pediatric Systems). DATA EXTRACTION: All 24 articles were reviewed by first and last authors and a spread sheet was constructed including sample size, potential biases, and conclusions. DATA SYNTHESIS: Discussions regarding incorporation of available evidence into our clinical practice were held at biannual meetings, as well as through email and virtual meetings. An expert consensus was determined through these discussions and confirmed through a modified Delphi process. CONCLUSIONS: Extracorporeal life support in hematopoietic cell transplantation patients is being used with increasing frequency and potentially improving survival. The Pediatric Acute Lung Injury and Sepsis Investigators hematopoietic cell transplantation-cancer immunotherapy subgroup has developed a framework to guide physicians in decision-making surrounding extracorporeal life support candidacy in pediatric hematopoietic cell transplantation patients. In addition to standard extracorporeal life support considerations, candidacy in the hematopoietic cell transplantation population should consider the following six factors in order of consensus agreement: 1) patient comorbidities; 2) underlying disease necessitating hematopoietic cell transplantation; 3) hematopoietic cell transplantation toxicities, 4) family and patient desires for goals of care; 5) hematopoietic cell transplantation preparatory regimen; and 6) graft characteristics. Although risk assessment may be individualized, data are currently insufficient to clearly delineate ideal candidacy. Therefore, we urge the onco-critical care community to collaborate and capture data to provide better evidence to guide physicians' decision-making in the future.

Veno-occlusive disease risk in pediatric patients with acute myeloid leukemia treated with gemtuzumab ozogamicin before allogeneic hematopoietic cell transplantation.

BACKGROUND: Gemtuzumab ozogamicin (GO) administered before allogeneic hematopoietic cell transplantation (alloHCT) has been linked to an increased risk of hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS). PROCEDURE: This retrospective analysis examined VOD/SOS risk and clinical outcomes in pediatric patients with acute myeloid leukemia who received myeloablative alloHCT in 2008-2011 with (n = 148) and without (n = 348; controls) prior GO exposure and were reported to the Center for International Blood and Marrow Transplant Research. RESULTS: Cumulative incidences (95% confidence interval [CI]) of VOD/SOS and severe VOD/SOS, respectively, at 100 days were 16% (11-23%) and 8% (4-13%) for GO-exposed patients and 10% (7-13%) and 3% (2-5%) for controls. With a median follow-up of approximately 7 years, the 5-year adjusted overall survival probability (95% CI) after alloHCT was 51% (43-58%) and 55% (50-60%) for GO-exposed patients and controls, respectively; three (4%) and one (<1%) deaths were attributed to VOD/SOS. In multivariate analyses, GO exposure was observed to be associated with an increased risk of VOD/SOS at 100 days, but was not associated with overall survival, disease-free survival, relapse, or nonrelapse mortality. CONCLUSIONS: Results suggest that GO treatment prior to alloHCT in pediatric patients may increase the risk of VOD/SOS but not death.

Functional remodeling of adrenal steroidogenic tissue by food deprivation in the lizard, Sceloporus undulatus.

The present study examined how food availability interacts with age to modulate lizard adrenal steroidogenic function at the cellular level. Adult male and juvenile male and female Eastern Fence Lizards (Sceloporus undulatus) underwent a period of food deprivation with or without a shorter re-feeding period. Lizards maintained on a full feeding regimen served as the controls. Across the feeding regimens, plasma corticosterone of adult lizards was unchanged whereas that of food-deprived juvenile lizards was increased nearly 7 times and this increase was normalized by a short re-feeding period. Freshly dispersed adrenocortical cells derived from these lizards were incubated with ACTH and the production of selected steroids was measured by highly specific radioimmunoassay. Net maximal steroid rates of juvenile cells were 161% greater than those of adult cells. Adult and juvenile progesterone rates were consistently suppressed by food deprivation (by nearly 48%) and were normalized by a re-feeding period, whereas divergent effects were seen with corticosterone and aldosterone rates. Food deprivation suppressed corticosterone rates of adult cells by 43% but not those of juvenile cells. In a reciprocal manner, food deprivation had no significant effect on aldosterone rates of adult cells, but it suppressed those of juvenile cells by 52%. A short re-feeding period normalized most rates in both adult and juvenile cells and further augmented the adult aldosterone rate by 54%. The effect of the feeding regimens on ACTH sensitivity varied with life stage and with steroid. The overall sensitivity of adult cells to ACTH was nearly three times that of juvenile cells. Collectively, the data presented here and data from previous work indicate that food restriction/deprivation in Sceloporus lizard species causes a functional remodeling of the adrenocortical tissue. Furthermore, life stage adds more complexity to this remodeling.

Comprehensive Prognostication in Critically Ill Pediatric Hematopoietic Cell Transplant Patients: Results from Merging the Center for International Blood and Marrow Transplant Research (CIBMTR) and Virtual Pediatric Systems (VPS) Registries.

Critically ill pediatric allogeneic hematopoietic cell transplant (HCT) patients may benefit from early and aggressive interventions aimed at reversing the progression of multiorgan dysfunction. Therefore, we evaluated 25 early risk factors for pediatric intensive care unit (PICU) mortality to improve mortality prognostication. We merged the Virtual Pediatric Systems and Center for International Blood and Marrow Transplant Research databases and analyzed 936 critically ill patients ≤21 years of age who had undergone allogeneic HCT and subsequently required PICU admission between January 1, 2009, and December 31, 2014. Of 1532 PICU admissions, the overall PICU mortality rate was 17.4% (95% confidence interval [CI], 15.6% to 19.4%) but was significantly higher for patients requiring mechanical ventilation (44.0%), renal replacement therapy (56.1%), or extracorporeal life support (77.8%). Mortality estimates increased significantly the longer that patients remained in the PICU. Of 25 HCT- and PICU-specific characteristics available at or near the time of PICU admission, moderate/severe pre-HCT renal injury, pre-HCT recipient cytomegalovirus seropositivity, <100-day interval between HCT and PICU admission, HCT for underlying acute myeloid leukemia, and greater admission organ dysfunction as approximated by the Pediatric Risk of Mortality 3 score were each independently associated with PICU mortality. A multivariable model using these components identified that patients in the top quartile of risk had 3 times greater mortality than other patients (35.1% versus 11.5%, P < .001, classification accuracy 75.2%; 95% CI, 73.0% to 77.4%). These data improve our working knowledge of the factors influencing the progression of critical illness in pediatric allogeneic HCT patients. Future investigation aimed at mitigating the effect of these risk factors is warranted.

The Impact of Donor Type on Outcomes and Cost of Allogeneic Hematopoietic Cell Transplantation for Pediatric Leukemia: A Merged Center for International Blood and Marrow Transplant Research and Pediatric Health Information System Analysis.

Allogeneic hematopoietic stem cell transplantation (alloHCT) may be associated with significant morbidity and mortality, resulting in increased healthcare utilization (HCU). To date, no multicenter comparative cost analyses have specifically evaluated alloHCT in children with acute leukemia. In this retrospective cohort study, we examined the relationship between survival and HCU while investigating the hypothesis that matched sibling donor (MSD) alloHCT has significantly lower inpatient HCU with unrelated donor (URD) alloHCT, and that among URDs, umbilical cord blood (UCB) alloHCT will have higher initial utilization but lower long-term utilization. Clinical and transplantation outcomes data from the Center for International Blood and Marrow Transplant Research (CIBMTR) were merged with inpatient cost data from the Pediatric Health Information System (PHIS) database using a probabilistic merge methodology. The merged dataset comprised US patients age 1 to 21 years who underwent alloHCT for acute leukemia between 2004 and 2011 with comprehensive CIBMTR data at a PHIS hospital. AlloHCT was analyzed by donor type, with specific analysis of utilization and costs using PHIS claims data. The primary outcomes of overall survival (OS), leukemia-free survival (LFS), and inpatient costs were evaluated using Kaplan-Meier curves and Cox and Poisson models. A total of 632 patients were identified in both the CIBMTR and PHIS data. The 5-year LFS was 60% for MSD alloHCT, 47% for well-matched matched unrelated donor bone marrow (MUD) alloHCT, 48% for mismatched unrelated donor alloHCT, and 45% for UCB alloHCT (P = .09). Total adjusted costs were significantly lower for MSD alloHCT versus MUD alloHCT by day 100 (adjusted cost ratio [ACR], .73; 95% confidence interval [CI], .62 to .86; P < .001), and higher for UCB alloHCT versus MUD alloHCT (ACR, 1.27; 95% CI, 1.11 to 1.45; P < .001). By 2 years, total adjusted costs remained significantly lower for MSD alloHCT compared with MUD alloHCT (ACR, .67; 95% CI, .56 to .81; P < .001) and higher for UCB alloHCT compared with MUD alloHCT (ACR, 1.25; 95% CI, 1.02 to 1.52; P = .0280). Our data show that UCB and MUD alloHCT provide similar survival outcomes; however, MUD alloHCT has a significant advantage in cost by day 100 and 2 years. More research is needed to determine whether the cost difference among URD alloHCT approaches remains significant with a larger sample size and/or beyond 2 years post-alloHCT.

Hematopoietic Stem-Cell Gene Therapy for Cerebral Adrenoleukodystrophy.

BACKGROUND: In X-linked adrenoleukodystrophy, mutations in ABCD1 lead to loss of function of the ALD protein. Cerebral adrenoleukodystrophy is characterized by demyelination and neurodegeneration. Disease progression, which leads to loss of neurologic function and death, can be halted only with allogeneic hematopoietic stem-cell transplantation. METHODS: We enrolled boys with cerebral adrenoleukodystrophy in a single-group, open-label, phase 2-3 safety and efficacy study. Patients were required to have early-stage disease and gadolinium enhancement on magnetic resonance imaging (MRI) at screening. The investigational therapy involved infusion of autologous CD34+ cells transduced with the elivaldogene tavalentivec (Lenti-D) lentiviral vector. In this interim analysis, patients were assessed for the occurrence of graft-versus-host disease, death, and major functional disabilities, as well as changes in neurologic function and in the extent of lesions on MRI. The primary end point was being alive and having no major functional disability at 24 months after infusion. RESULTS: A total of 17 boys received Lenti-D gene therapy. At the time of the interim analysis, the median follow-up was 29.4 months (range, 21.6 to 42.0). All the patients had gene-marked cells after engraftment, with no evidence of preferential integration near known oncogenes or clonal outgrowth. Measurable ALD protein was observed in all the patients. No treatment-related death or graft-versus-host disease had been reported; 15 of the 17 patients (88%) were alive and free of major functional disability, with minimal clinical symptoms. One patient, who had had rapid neurologic deterioration, had died from disease progression. Another patient, who had had evidence of disease progression on MRI, had withdrawn from the study to undergo allogeneic stem-cell transplantation and later died from transplantation-related complications. CONCLUSIONS: Early results of this study suggest that Lenti-D gene therapy may be a safe and effective alternative to allogeneic stem-cell transplantation in boys with early-stage cerebral adrenoleukodystrophy. Additional follow-up is needed to fully assess the duration of response and long-term safety. (Funded by Bluebird Bio and others; STARBEAM ClinicalTrials.gov number, NCT01896102 ; ClinicalTrialsRegister.eu number, 2011-001953-10 .).

Respiratory pathogens associated with intubated pediatric patients following hematopoietic cell transplant.

BACKGROUND: We describe organisms found in the respiratory tracts of a multicenter cohort of pediatric hematopoietic cell transplant (HCT) recipients with respiratory failure. METHODS: Twelve centers contributed up to 25 pediatric allogeneic HCT recipients requiring mechanical ventilation for respiratory failure to a retrospective database. Positive respiratory pathogens and method of obtaining sample were recorded. Outcomes were assessed using Mann-Whitney U test or chi-squared analysis. RESULTS: Of the 222 patients in the database, ages 1 month through 21 years, 34.6% had a positive respiratory culture. 105 pathogens were identified in 77 patients; of those, 48.6% were viral, 34.3% bacterial, 16.2% fungal, and 1% parasitic. PICU mortality with a respiratory pathogen was 68.8% compared to 54.9% for those without a respiratory pathogen (P = .045). Those with a positive respiratory pathogen had longer PICU length of stay, 20 days (IQR 14.0, 36.8) vs 15 (IQR 6.5, 32.0), P = .002, and a longer course of mechanical ventilation, 17 days (IQR 10, 29.5) vs 8 (3, 17), P < .0001. Method of pathogen identification, type of pathogen, and the presence of multiple pathogens were not associated with changes in PICU outcomes. CONCLUSIONS: In this multicenter retrospective cohort of intubated pediatric post-HCT patients, there was high variability in the respiratory pathogens identified. Type of pathogen and method of detection did not affect PICU mortality. The presence of any organism leads to increased PICU mortality, longer PICU stay, and increased duration of mechanical ventilation suggesting that early detection and treatment of pathogens may be beneficial in this population.

Thrombotic Microangiopathy Following Pediatric Autologous Hematopoietic Cell Transplantation: A Report of Significant End-Organ Dysfunction in Eculizumab-Treated Survivors.

Transplantation-associated thrombotic microangiopathy (TA-TMA) is a known complication of autologous hematopoietic cell transplantation (aHCT), particularly in children with neuroblastoma. We describe a pediatric single-institution experience of TA-TMA after aHCT. Data were abstracted from the medical record of patients who underwent aHCT between January 1, 2008, and July 1, 2018, at Boston Children's Hospital. TA-TMA was diagnosed using either the International Working Group criteria or the "probable TA-TMA criteria" of Cho et al. Overall, 318 aHCTs were performed in 243 patients. Nine patients (3.7%) were diagnosed with TA-TMA. TA-TMA occurred most frequently in children with neuroblastoma (n = 7; 78%), all of whom were conditioned with carboplatin, etoposide, and melphalan. The median age at aHCT in children who developed TA-TMA was 3 years, 5 months (range, 18 months to 25 years). TMA was diagnosed at a median of 35 days (range, 8 to 106 days) after stem cell infusion. On a retrospective chart review using the same criteria used by the provider, patients met criteria a median of 5 days before the clinical diagnosis (range, 0 to 58 days). Eight patients had renal involvement at presentation, including nephrotic range proteinuria and severe hypertension, requiring from 2 to 6 antihypertensive medications. Two patients presented with multiorgan failure. Six patients were treated with eculizumab a median of 0 days after TA-TMA diagnosis (range, 0 to 11 days). On retrospective review, patients were treated a median of 18 days (range, 0 to 58 days) after meeting criteria for TA-TMA. Before initiation of therapy, 4 of 6 patients checked for serum complement levels had normal values, 1 had elevated CH50 and 1 had elevated sC59-b and CH50. All patients had CH50 levels within the target range (≤3 CAE) after induction therapy. Two patients (33%) had no response to eculizumab and died of multiorgan failure. The other 4 had both a hematologic response with transfusion independence (median, 6.5 weeks; range, 4 to 9 weeks) and renal response, defined as resolution of nephrotic range proteinuria (median, 21 weeks; range, 13 to 25 weeks). Among the eculizumab-treated survivors, 2 patients remained on prolonged eculizumab therapy, and one had recurrence of TA-TMA after discontinuation of eculizumab. All 4 eculizumab treated survivors have persistent organ dysfunction. Three children were treated with supportive care only; 2 died of relapsed cancer, and the third is alive with stage 2 chronic kidney disease. The median duration of follow-up after TA-TMA diagnosis was 2.5 years (range, 9 months to 4 years). The 1-year overall survival was 78% (SE = 14%). However, regardless of treatment, no survivors had complete normalization of function in all organs. Three children with normal serum CH50 and sc5b-9 levels responded to eculizumab. This report highlights the importance of maintaining a high suspicion for TA-TMA after aHCT. Further study is warranted to identify individual risk factors for TMA after aHCT, predict the response to eculizumab, and capture long-term sequelae in survivors.

Severe, persistent neurotoxicity after transplant-associated thrombotic microangiopathy in a pediatric patient despite treatment with eculizumab.

BACKGROUND: TA-TMA is a described complication of aHCT in children with neuroblastoma. Outcomes are poor with mortality rates approaching 60%. Described late effects in survivors include chronic kidney disease and persistent pulmonary hypertension. CASE: We report a case of a 2-year-old with neuroblastoma who developed severe TA-TMA 35 days after high dose chemotherapy and autologous stem cell rescue. He presented with respiratory failure, pericardial and pleural effusions, hemolysis, hypertension, and mild altered mental status. He was mechanically ventilated for 3 weeks and after sedation was lifted, he was minimally responsive. He was treated with eculizumab with resolution of hemolysis, kidney injury and polyserositis. Initially he was more responsive; however, after almost a year of intensive therapy he remained nonverbal and had persistent irritability and behavioral changes. He had an extensive negative evaluation. On day +345, he presented with severe, refractory epilepsy. Three years after TA-TMA, he continues to have severe neurologic disabilities. CONCLUSIONS: To our knowledge, persistent neurologic toxicity has not been reported in TA-TMA. However, deficits and seizures are reported in other TMAs, particularly in children with atypical HUS who present with significant neurologic changes at diagnosis. Our patient's persistent neurologic disability despite eculizumab response in all other involved organs may reflect irreversible damage. This case describes a new long-term sequela of TA-TMA and highlights the need for further studies to understand both acute and long-term neurologic complications of this disease.

Risk-factors Associated With Poor Outcomes in VEO-IBD Secondary to XIAP Deficiency: A Case Report and Literature Review.

Very early onset inflammatory bowel disease (VEO-IBD) represents a diagnostic and treatment challenge. Here we present a case of VEO-IBD secondary to a mutation in BIRC4 gene, which encodes X-linked inhibitor of apoptosis protein (XIAP), in a 17-month-old boy with severe failure to thrive, intractable diarrhea, and hepatosplenomegaly. Endoscopy and histology identified only mild duodenitis and ileitis, but severe pancolitis with crypt abscesses and epithelium apoptosis. Minimal improvement in symptoms was achieved with total parenteral nutrition (TPN), intravenous (IV) corticosteroids, and tacrolimus, whereas induction and maintenance therapy with adalimumab led to complete remission. After 6 months, the patient developed hemophagocytic lymphohistiocytosis and eventually died due to multisystem organ failure. A review of the literature revealed that some patients with VEO-IBD secondary to XIAP deficiency develop symptoms that are refractory to medical and surgical management, while initial reports suggest that allogeneic hematopoietic stem cell transplantation (HSCT), with reduced intensity conditioning, can successfully induce long-lasting remission and may even be curative. We propose that in patients with XIAP deficiency a constellation of symptoms including colitis at an early age, severe failure to thrive, and splenomegaly/hepatosplenomegaly can identify a subgroup of patients at high risk of experiencing medically refractory IBD phenotype and increased mortality. Hematopoietic stem cell transplant should be considered early in these high-risk patients, as it may resolve both their intestinal inflammation and a risk of developing life threatening hemophagocytic lymphohistiocytosis .

Sun exposure and protection practices in children after allogeneic hematopoietic stem cell transplantation: A Survey-Based Cross-Sectional Cohort Study.

BACKGROUND/OBJECTIVE: Pediatric hematopoietic stem cell transplantation (HSCT) patients are at an increased risk for skin cancers. Sun exposure is a significant modifiable environmental risk factor. While patient education on sun protection and avoidance behaviors with regular dermatology evaluations are crucial for pediatric HSCT patients, the real-life practice of these sun-protection recommendations in this patient population compared to their peers is unknown. METHODS: A survey-based cross-sectional cohort study was performed in pediatric HSCT patients seen at the Dana-Farber Cancer Institute and Boston Children's Hospital over a 1.5-year period compared with age/sex/Fitzpatrick skin phototype-matched healthy controls. Study participants were surveyed using the validated Glanz survey for pediatric sun protection behavioral research. RESULTS: Eighty-five pediatric HSCT patients and 85 controls completed the study. Pediatric HSCT patients more frequently used sunscreen, hats, umbrellas, and sunglasses and obtained full-body skin exams compared to controls. No difference was observed in sun exposure during hours of peak sun intensity, frequency of purposeful tanning, tanning bed use, and the number of painful sunburns received between pediatric HSCT patients and controls. CONCLUSIONS: Although pediatric HSCT patients practice more sun protection behaviors, they experienced harmful sunburns and intentional tanning behaviors at the same rate as their peers. Patient-directed counseling and strategies to improve patient adherence to optimal sun protection behaviors could have a significant impact on the dermatology quality of life in pediatric HSCT patients.