Gene therapy holds promise as a life-changing option for individuals with genetic variants that give rise to disease. FDA-approved gene therapies for Spinal Muscular Atrophy (SMA), cerebral adrenoleukodystrophy, β-Thalassemia, hemophilia A/B, retinal dystrophy, and Duchenne Muscular Dystrophy have generated buzz around the ability to change the course of genetic syndromes. However, this excitement risks over-expansion into areas of genetic disease that may not fit the current state of gene therapy. While in situ (targeted to an area) and ex vivo (removal of cells, delivery, and administration of cells) approaches show promise, they have a limited target ability. Broader in vivo gene therapy trials have shown various continued challenges, including immune response, use of immune suppressants correlating to secondary infections, unknown outcomes of overexpression, and challenges in driving tissue-specific corrections. Viral delivery systems can be associated with adverse outcomes such as hepatotoxicity and lethality if uncontrolled. In some cases, these risks are far outweighed by the potentially lethal syndromes for which these systems are being developed. Therefore, it is critical to evaluate the field of genetic diseases to perform cost-benefit analyses for gene therapy. In this work, we present the current state while setting forth tools and resources to guide informed directions to avoid foreseeable issues in gene therapy that could prevent the field from continued success.

Lung injury is a major determinant of survival after pediatric hematopoietic cell transplantation (HCT). A deeper understanding of the relationship between pulmonary microbes, immunity, and the lung epithelium is needed to improve outcomes. In this multicenter study, we collected 278 bronchoalveolar lavage (BAL) samples from 229 patients treated at 32 children's hospitals between 2014-2022. Using paired metatranscriptomes and human gene expression data, we identified 4 patient clusters with varying BAL composition. Among those requiring respiratory support prior to sampling, in-hospital mortality varied from 22-60% depending on the cluster (p=0.007). The most common patient subtype, Cluster 1, showed a moderate quantity and high diversity of commensal microbes with robust metabolic activity, low rates of infection, gene expression indicating alveolar macrophage predominance, and low mortality. The second most common cluster showed a very high burden of airway microbes, gene expression enriched for neutrophil signaling, frequent bacterial infections, and moderate mortality. Cluster 3 showed significant depletion of commensal microbes, a loss of biodiversity, gene expression indicative of fibroproliferative pathways, increased viral and fungal pathogens, and high mortality. Finally, Cluster 4 showed profound microbiome depletion with enrichment of Staphylococci and viruses, gene expression driven by lymphocyte activation and cellular injury, and the highest mortality. BAL clusters were modeled with a random forest classifier and reproduced in a geographically distinct validation cohort of 57 patients from The Netherlands, recapitulating similar cluster-based mortality differences (p=0.022). Degree of antibiotic exposure was strongly associated with depletion of BAL microbes and enrichment of fungi. Potential pathogens were parsed from all detected microbes by analyzing each BAL microbe relative to the overall microbiome composition, which yielded increased sensitivity for numerous previously occult pathogens. These findings support personalized interpretation of the pulmonary microenvironment in pediatric HCT, which may facilitate biology-targeted interventions to improve outcomes.

Introduction: Lineage switch (LS) refers to the transformation of acute leukemia from one cell lineage to another (e.g., lymphoid (ALL) to myeloid (AML)). This rare phenomenon, distinct from treatment induced malignancy (i.e., t-AML) and mixed phenotype acute leukemia (MPAL), is increasingly being observed following cell surface antigen targeting. Given challenges in the diagnosis and treatment of LS, Project EVOLVE was developed to globally identify cases of LS following immunotherapy. Methods: A protocol and data collection form for this IRB exempt study was widely disseminated to capture deidentified LS case information across multiple centers and cancer consortia. This included collection of data from published reports of LS, with authors contacted to obtain additional information. For this analysis, LS was defined by the emergence of cell-surface markers warranting reclassification of the original leukemia as a different lineage derivation based on the immunophenotype, including cases of AML emerging alongside the original ALL. “Confirmed” LS cases included those where retention of original cytogenetic or molecular aberrations and/or the clonal immunoglobulin rearrangement patterns were verified to confirm the clonal relationship. “Suspected” LS cases included those where samples to confirm clonality marker retention could not be obtained, but the clinical presentation was consistent with LS. The term “transition” was applied when immunophenotypic shifts were transient. Cases with new cytogenetic abnormalities unrelated to the original diagnosis and compatible with t-AML were excluded. Statistical analysis was primarily descriptive. Data cut-off was July 26, 2023. Results: A total of 58 cases were identified, including 19 cases referenced in prior publications. Of the 58, 11 cases were excluded from this initial analysis, including: 4 cases of t-AML, 2 cases of T-ALL to AML, and 5 “transition” cases. Collectively, 47 cases of LS (43 “confirmed”; 4 “suspected”), spanning across 3 continents and 8 countries, were analyzed. (Fig. 1A) Cases included transition from B-ALL to AML in 36 (76.6%) and to MPAL/biphenotypic/ambiguous lineage in 11 (23.4%). Two likely had MPAL at diagnosis and a third with chronic myeloid leukemia. The median age at initial diagnosis was 8.4 years (range, 1 day-76.5 years); median age at LS presentation was 11.0 years (range 0.4-77.3 years). Twenty-three (48.9%) were male and 19 (40.4%) had prior stem cell transplant (SCT). Baseline cytogenetics showed KMT2A rearrangement in 27 (57.4%). Baseline myeloid antigen co-expression was seen in 22 of 23 patients with submitted data, but variation in degree of expression across patients and antigens was substantial. The most proximal immunotherapy prior to development of LS was CAR T-cells in 23 (48.9%) and blinatumomab in 24 (51.1%). The median time from the most proximal immunotherapy to development of LS was 1.6 months (range, 7 days-36.5 months). In 7 (29.2%) patients receiving blinatumomab, LS developed during the infusion. LS presented as isolated marrow relapse in 27 (57.4%), isolated CNS in 2 (4.3%), isolated non-CNS extramedullary disease in 3 (6.4%), combined relapse in 14 (29.8%) and unreported in 1. First line treatment for LS was chemotherapy induction in 31 (66.0%), palliative care/no therapy in 8 (17.0%), and alternative therapies in the remaining 8 (17.0%). In 35 (74.5%) patients, remission induction was the goal of first line therapy. Fifteen (31.9%) achieved a complete remission (CR) of whom 2 were treated with palliative intent. Across all patients, 8 (17.0%) are alive in remission, the longest being 4.7 years from LS diagnosis; 2 (4.3%) are alive with active LS and 37 (78.7%) died from LS, their original disease, or complications of treatment of LS (Fig 1B). For those alive in CR (n=8), 7 (87.5%) proceeded to a consolidative SCT for treatment of LS and 1 patient, an octogenarian remains in remission after AML directed therapy. Conclusions: LS is emerging as an important mechanism of immune escape following immunotherapy. Project EVOLVE provides the largest dataset of patients with LS to date. This systematic, international effort reveals substantial complexity and variability in diagnosing and managing LS. Unfortunately, outcomes following LS are grim, underscoring the critical need to identify risk factors of and optimal therapies for this leukemia transformation.

Abstract Background Antimicrobial stewardship (AS) programs aim to slow the growing threat of antimicrobial resistance. The majority of antibiotic prescribing occurs in outpatient settings. This study examines the effect of an AS intervention bundle on the proportion of inappropriate antibiotic prescriptions given to adult patients with bronchitis in outpatient settings of a large healthcare system. Methods The Institutional Review Board approved this retrospective study of antibiotic prescription rates for adults (≥18 years old) diagnosed with bronchitis (identified using ICD-10 codes J20.9 or J20.8) during 2020 and 2021 in outpatient settings. An AS intervention bundle involving training and auditing of physicians’ antibiotic prescribing habits was enacted in January of 2021. A total of 8,176 encounters were reviewed for appropriateness of antibiotic prescriptions. Instances where no antibiotics were prescribed or antibiotics were prescribed for a comorbid condition were considered appropriate. Percentages of inappropriate antibiotic prescribing pre- and post-intervention were then compared via Chi-square analysis using SAS Enterprise Guide version 7.15 software. Results The proportion of inappropriate antibiotic prescribing for bronchitis decreased significantly from 44.9% pre-intervention to 32.5% post-intervention (p< 0.0001). Comparison of inappropriate prescribing rates by month showed significant decreases between the pre- and post-intervention periods in March (48.1% to 31.8%, p=0.0002), October (44.4% to 30.3%, p< 0.0001), and November (42.2% to 27.0%, p< 0.0001). Conclusion AS activities can decrease inappropriate antibiotic prescribing for bronchitis in outpatient settings. Further analyses on site-specific, seasonal and demographic differences on the effect of our AS intervention bundle may further enlighten on how programs can decrease unnecessary antibiotic use for respiratory tract infections. Disclosures All Authors: No reported disclosures

Abstract Background Amoxicillin is a first-line agent for most pediatric acute respiratory infections (ARIs). In Fall 2022, a nationwide amoxicillin shortage occurred. This study sought to provide precise estimates in outpatient amoxicillin usage during the shortage, using a nationally representative sample of institutions providing pediatric care. Methods Twenty-two institutions from the Sharing Antimicrobial Reports for Pediatric Stewardship Outpatient (SHARPS-OP) Collaborative provided aggregate quarterly data from Jan 2019 - Dec 2022. Data included total counts of encounters with an ARI ICD-10 code and proportions of ARIs treated with any oral antibiotic, amoxicillin, and azithromycin. Data were stratified by location type (Emergency Department [ED], Urgent Care [UC], and primary care clinics [PCC]). We compared ARI prescribing (ARI encounters resulting in any antibiotic prescription) and the amoxicillin and azithromycin indices (ARI encounters resulting in amoxicillin or azithromycin prescription out of ARI encounters resulting in any antibiotic prescription) between pre-shortage (Jan 2019 - Sep 2022) and shortage (Oct 2022 - Dec 2022) time periods by location type. Results A total 4.89 million ARI encounters (4.24 million during pre-shortage and 0.65 million during the shortage) were reported across 22 institutions. Overall antibiotic prescribing for ARI encounters changed slightly from pre-shortage to shortage period for ED (28.7% to 22.6%; delta: -6.1 [-6.4, -5.8]), UC (41.1% to 39.6%; delta: -1.6 [-1.8, -1.3]) and PCC (38.1% to 38.1%; delta: 0.03 [0.001, -0.003]). Substantial declines in the amoxicillin index were observed for ED (76.1% to 60.9%; delta: -15.1 [-15.8, -14.5]), UC (71.9% to 60.1%; delta: -11.7 [-12.1, -11.3]) and PCC (63.9% to 53.3%; delta: -10.6 [-14.2, -9.6] with considerable variation within and between SHARPS-OP institutions (Figure 1). Azithromycin use among ARI encounters decreased slightly during the amoxicillin shortage (-0.3% [-0.38%, -0.20%]).Figure 1:Amoxicillin indices for pre-shortage and amoxicillin shortage time periods for included SHARPS-OP institutions, stratified by location type.Location types: Emergency Department [ED]; Urgent Care [UC]; Primary Care Clinic [Primary] Conclusion Amoxicillin utilization disproportionately decreased compared to overall antibiotic prescribing for ARIs during the shortage. Providers may have prescribed alternative antibiotics rather than no therapy for ARIs. Disclosures Michael J. Smith, M.D., M.S.C.E, Merck: Grant/Research Support|Pfizer: Grant/Research Support Bethany A. Wattles, PharmD, MHA, Merck: Grant/Research Support

Systematic and comprehensive data acquisition from the electronic health record (EHR) is critical to the quality of data used to improve patient care. We described EHR tools, workflows, and data elements that contribute to core quality metrics in the Type 1 Diabetes Exchange Quality Improvement Collaborative (T1DX-QI). We conducted interviews with quality improvement (QI) representatives at 13 T1DX-QI centers about their EHR tools, clinic workflows, and data elements. All centers had access to structured data tools, nine had access to patient questionnaires and two had integration with a device platform. There was significant variability in EHR tools, workflows, and data elements, thus the number of available metrics per center ranged from four to 17 at each site. Thirteen centers had information about glycemic outcomes and diabetes technology use. Seven centers had measurements of additional self-management behaviors. Centers captured patient-reported outcomes including social determinants of health (n = 9), depression (n = 11), transition to adult care (n = 7), and diabetes distress (n = 3). Various stakeholders captured data including health care professionals, educators, medical assistants, and QI coordinators. Centers that had a paired staffing model in clinic encounters distributed the burden of data capture across the health care team and was associated with a higher number of available data elements. The lack of standardization in EHR tools, workflows, and data elements captured resulted in variability in available metrics across centers. Further work is needed to support measurement and subsequent improvement in quality of care for individuals with type 1 diabetes.

ABSTRACT Epigenetic age acceleration is a risk factor for chronic diseases of ageing and may reflect aspects of biological ageing. However, few studies have examined epigenetic ageing during the early neonatal period in preterm infants, who are at heightened risk of developmental problems. We examined relationships between neonatal age acceleration, neonatal morbidities, and neurobehavioral domains among very preterm (<30 weeks gestation) infants to characterize whether infants with early morbidities or different neurobehavioral characteristics had accelerated or decelerated epigenetic ageing. This study uses data from the Neonatal Neurobehavior and Outcomes in Very Preterm Infants (NOVI) study, restricted to infants with data on variables assessed (n = 519). We used generalized estimating equations to test for differences in age acceleration associated with severe neonatal medical morbidities and neurobehavioral characteristics. We found that infants with neonatal morbidities, in particular, bronchopulmonary dysplasia (BPD), had accelerated epigenetic age – and some evidence that infants with hypertonicity and asymmetric reflexes had increased and decreased age acceleration, respectively. Adjustment for gestational age attenuated some associations, suggesting that the relationships observed may be driven by the duration of gestation. Our most robust finding shows that very preterm infants with neonatal morbidities (BPD in particular) exhibit age acceleration, but most neonatal neurobehavioral characteristics and morbidities are not associated with early life age acceleration. Lower gestational age at birth may be an upstream factor driving these associations.

Acute bronchiolitis causes many hospitalizations in children younger than 2 years. Early enteral nutrition is associated with improved outcomes in these patients. However, often nutrition is withheld when patients require noninvasive respiratory support because of the risk of aspiration worsening respiratory failure, possibly requiring intubation. We hypothesize that achieving goal energy intake is associated with a lower intubation rate in hospitalized children with bronchiolitis who require noninvasive ventilation. This retrospective cohort study examined the association between goal enteral nutrition (60% of dietary reference energy intake) and intubation rates. We grouped patients by severity of illness and compared intubation rates in those who met goal energy to those who did not. We use stratified analysis methods (for both level of respiratory support and feeding route) to evaluate progression to intubation. Of the 272 patients, 215 met goal feeds. These groups had similar demographics, but the goal-feeds group started on higher respiratory support in the pediatric intensive care unit. We found that 4.65% of the patients who met goal feeds required intubation compared with 24.6% of patients who did not meet goal feeds (P < 0.0001), even after controlling for respiratory status at admission and time of feed initiation and feeding route. We observed when adjusting for severity, feeding route, and respiratory support, achieving goal energy intake remained associated with a lower rate of intubation, without higher rates of aspiration. Confounding factors include practice variation and difference in severity of illness that objective scoring may have missed.

Treatment for childhood solid tumors may lead to an increased risk for gonadal dysfunction/infertility. Discussion of risk should occur at diagnosis, any changes in therapy, and during survivorship. Gonadotoxic therapies were abstracted from 32 Children’s Oncology Group (COG) phase III, frontline solid tumor protocols, in use from 2000-2022. Risk for gonadal dysfunction/infertility was assessed based on gonadotoxic therapies, sex, and pubertal status and assigned as minimal, significant, and high following the Oncofertility Consortium Pediatric Initiative Network (PIN) risk stratification. Most protocols (65.6%, 21/32) contained at least one therapeutic arm with a high level of increased risk. Solid tumor therapies present challenges in risk stratification due to response-adjusted therapy and the need to account for radiation field in the risk assessment. This guide hopes to serve as a tool to assist in standardizing gonadotoxic risk assessments across disciplines and improve referral for fertility services and reproductive health counseling for patients receiving COG based solid tumor therapy.