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Sickle cell disease (SCD) is an inherited red blood cell disease that results in a multitude of medical complications, including an increased risk of invasive disease caused by encapsulated bacteria, such as Streptococcus pneumoniae. Pneumococcal vaccines have contributed to a significant reduction in pneumococcal disease (PD) in children and adults, including those with SCD. This phase 3 study evaluated the safety and immunogenicity of V114, a 15-valent pneumococcal conjugate vaccine (PCV), in children with SCD. A total of 103 children aged 5 to 17 years with SCD were randomized and received a single dose of V114 or Prevnar 13 (PCV13). Safety was evaluated as the proportion of participants with adverse events (AEs). Serotype-specific immunoglobulin G (IgG) levels and opsonophagocytic activity (OPA) were measured immediately before vaccination and 30 days after vaccination. Overall, the rates of injection-site and systemic AEs reported after vaccination were similar between the vaccination groups. Up to 6 months after vaccination, serious AEs were those expected for patients with SCD, and none were assessed to be vaccine related. IgG geometric mean concentrations (GMCs) and OPA geometric mean titers (GMTs) for the 13 shared serotypes were generally comparable between recipients of V114 and PCV13. Additionally, V114 induced immune responses to serotypes 22F and 33F, which are not included in PCV13. The safety and tolerability profiles of V114 were consistent with those reported for PCV13. Immune responses following vaccination with V114 were generally comparable to PCV13 for the shared serotypes and higher for unique serotypes 22F and 33F. These results support the use of V114 in children with SCD. This trial was registered at www.clinicaltrials.gov as #NCT03731182.

Purpose:Surgery often represents the best chance for disease control in locoregionally recurrent squamous cell carcinoma of the head and neck (SCCHN). We investigated dual immune-checkpoint inhibition [anti–PD-1, nivolumab (N), and anti-KIR, lirilumab (L)] before and after salvage surgery to improve disease-free survival (DFS).Patients and Methods:In this phase II study, patients received N (240 mg) + L (240 mg) 7 to 21 days before surgery, followed by six cycles of adjuvant N + L. Primary endpoint was 1-year DFS; secondary endpoints were safety, pre-op radiologic response, and overall survival (OS). Correlatives included tumor sequencing, PD-L1 scoring, and immunoprofiling.Results:Among 28 patients, the median age was 66, 86% were smokers; primary site: 9 oral cavity, 9 oropharynx, and 10 larynx/hypopharynx; 96% had prior radiation. There were no delays to surgery. Grade 3+ adverse events: 11%. At the time of surgery, 96% had stable disease radiologically, one had progression. Pathologic response to N + L was observed in 43% (12/28): 4/28 (14%) major (tumor viability, TV ≤ 10%) and 8/28 (29%) partial (TV ≤ 50%). PD-L1 combined positive score (CPS) at surgery was similar regardless of pathologic response (P = 0.71). Thirteen (46%) recurred (loco-regional = 10, distant = 3). Five of 28 (18%) had positive margins, 4 later recurred. At median follow-up of 22.8 months, 1-year DFS was 55.2% (95% CI, 34.8–71.7) and 1-year OS was 85.7% (95% CI, 66.3–94.4). Two-year DFS and OS were 64% and 80% among pathologic responders.Conclusions:(Neo)adjuvant N + L was well tolerated, with a 43% pathologic response rate. We observed favorable DFS and excellent 2-year OS among high-risk, previously treated patients exhibiting a pathologic response. Further evaluation of this strategy is warranted.

Supplementary Data from Neoadjuvant and Adjuvant Nivolumab and Lirilumab in Patients with Recurrent, Resectable Squamous Cell Carcinoma of the Head and Neck

Cardiovascular disease is a major cause of mortality in patients with sickle cell disease (SCD). Niss et al previously reported that cardiac magnetic resonance in 25 patients showed universal myocardial fibrosis, which they correlated with increased extracellular volume fraction (ECV). In the current study, they compared patients with SCD who were treated with hydroxyurea or transfusion at age

Oral leukoplakia is common and may, in some cases, progress to carcinoma. Proliferative leukoplakia is a progressive, often multifocal subtype with a high rate of malignant transformation compared with the more common localized leukoplakia. We hypothesized that the immune microenvironment and gene expression patterns would be distinct for proliferative leukoplakia compared with localized leukoplakia. We summarize key clinicopathologic features among proliferative leukoplakia and localized leukoplakia and compare cancer-free survival (CFS) between subgroups. We analyze immunologic gene expression profiling in proliferative leukoplakia and localized leukoplakia tissue samples (NanoString PanCancer Immune Oncology Profiling). We integrate immune cell activation and spatial distribution patterns in tissue samples using multiplexed immunofluorescence and digital image capture to further define proliferative leukoplakia and localized leukoplakia. Among N = 58 patients (proliferative leukoplakia, n = 29; localized leukoplakia, n = 29), only the clinical diagnosis of proliferative leukoplakia was associated with significantly decreased CFS (HR, 11.25; P < 0.01; 5-year CFS 46.8% and 83.6% among patients with proliferative leukoplakia and localized leukoplakia, respectively). CD8+ T cells and T regulatory (Treg) were more abundant among proliferative leukoplakia samples (P < 0.01) regardless of degree of epithelial dysplasia, and often colocalized to the dysplasia–stromal interface. Gene set analysis identified granzyme M as the most differentially expressed gene favoring the proliferative leukoplakia subgroup (log2 fold change, 1.93; Padj < 0.001). Programmed death ligand 1 (PD-L1) was comparatively overexpressed among proliferative leukoplakia samples, with higher (>5) PD-L1 scores predicting worse CFS (Padj < 0.01). Proliferative leukoplakia predicts a high rate of malignant transformation within 5 years of diagnosis. A prominent CD8+ T-cell and Treg signature along with relative PD-L1 overexpression compared with localized leukoplakia provides strong rationale for PD-1/PD-L1 axis blockade using preventative immunotherapy. Significance: This is the first in-depth profiling effort to immunologically characterize high-risk proliferative leukoplakia as compared with the more common localized leukoplakia. We observed a notable cytotoxic T-cell and Treg signature with relative overexpression of PD-L1 in high-risk proliferative leukoplakia providing a strong preclinical rationale for investigating PD-1/PD-L1 axis blockade in this disease as preventative immunotherapy.

Although hydroxyurea (HU) is an effective treatment for sickle cell anemia, uptake remains low. Shared decision making (SDM) is a recommended strategy for HU initiation to elicit family preferences; however, clinicians lack SDM training. We implemented an immersive virtual reality (VR) curriculum at eight pediatric institutions to train clinicians on SDM that included counseling virtual patients. Clinicians’ self-reported confidence significantly improved following the VR simulations on all communication skills assessed, including asking open-ended questions, eliciting specific concerns, and confirming understanding (ps ≤ 0.01 for all). VR may be an effective method for educating clinicians to engage in SDM for HU.

Sickle cell disease (SCD) is an inherited red blood cell disease that results in a multitude of medical complications, including increased risk of invasive disease caused by encapsulated bacteria such as Streptococcus pneumoniae. Pneumococcal vaccines have contributed to significant reduction in pneumococcal disease (PD) in children and adults, including those with SCD. This phase 3 study evaluated the safety and immunogenicity of V114, a 15-valent pneumococcal conjugate vaccine (PCV), in children with SCD. A total of 103 children 5 to 17 years of age with SCD were randomized and received a single dose of V114 or Prevnar 13™ (PCV13). Safety was evaluated as the proportion of participants with adverse events (AEs). Serotype-specific immunoglobulin G (IgG) and opsonophagocytic activity (OPA) were measured immediately prior to and 30 days after vaccination. Overall, rates of injection-site and systemic AEs reported postvaccination were similar between vaccination groups. Up to 6 months postvaccination, serious AEs were those expected in SCD patients, and none was assessed to be vaccine related. IgG geometric mean concentrations (GMCs) and OPA geometric mean titers (GMTs) for 13 shared serotypes were generally comparable between recipients of V114 and PCV13. Additionally, V114 induced immune responses to serotypes 22F and 33F, not included in PCV13. Safety and tolerability profiles of V114 were consistent to those reported with PCV13. Immune responses following vaccination with V114 were generally comparable to PCV13 for the shared serotypes and higher for unique serotypes 22F and 33F. These results support the use of V114 in children with SCD. Trial Registration: ClinicalTrials.gov: NCT03731182; EudraCT: 2018-001152-35.

To describe the prevalence, severity, and management of anemia in a cohort of children with recessive dystrophic epidermolysis bullosa (RDEB) and to highlight the use of soluble transferrin receptor (sTfR) to diagnose iron deficiency in this chronic inflammatory state.We studied a cohort of 114 patients with RDEB followed at a pediatric hospital-based Epidermolysis Bullosa Center from 2010 to 2020; data were prospectively tracked in a comprehensive clinical database that captured all visits, laboratory tests, iron infusions, and transfusions. The primary outcome was occurrence of anemia, which was assessed by age and sex, with and without transfusion support. Secondary outcomes included iron status using a combination of ferritin and sTfR levels, the cumulative incidence of parenteral iron therapy and transfusions, and survival.In RDEB, anemia begins in the first year of life and becomes more frequent and severe with age. The prevalence of iron deficiency anemia (IDA) estimated by ferritin was 33.6% (37/110), but the sTfR/logIndividuals with RDEB have a high burden of anemia (IDA and anemia of inflammation) that requires frequent medical interventions. The sTfR/log

Sickle cell disease (SCD) requires coordinated, specialized medical care for optimal outcomes. There are no United States (US) guidelines that define a pediatric comprehensive SCD program. We report a modified Delphi consensus-seeking process to determine essential, optimal, and suggested elements of a comprehensive pediatric SCD center. Nineteen pediatric SCD specialists participated from the US. Consensus was predefined as 2/3 agreement on each element's categorization. Twenty-six elements were considered essential (required for guideline-based SCD care), 10 were optimal (recommended but not required), and five were suggested. This work lays the foundation for a formal recognition process of pediatric comprehensive SCD centers.

Children with sickle cell disease (SCD) who began hydroyxurea before age five years scored no differently on a measure of cognitive funciton than age, sex, and race-matched unaffected peers.

Neurologic complications are common in patients with sickle cell anemia (SCA), but conventional tools such as MRI and transcranial Doppler ultrasonography (TCD) do not fully assess cerebrovascular pathology. Cerebral tissue oximetry measures mixed oxygen saturation in the frontal lobes (SCT O2 ) and provides early prognostic information about tissue at risk of ischemic injury. Untreated patients with SCA have significantly lower SCT O2 than healthy controls that declines with age. Hydroxyurea is effective in preventing many SCA-related complications, but the degree to which it preserves normal neurophysiology is unclear. We analyzed participants enrolled in the Therapeutic Response Evaluation and Adherence Trial (TREAT, NCT02286154), which enrolled participants initiating hydroxyurea using individualized dosing (New Cohort) and those previously taking hydroxyurea (Old Cohort) and was designed to monitor the long-term benefits of hydroxyurea. Cerebral oximetry was performed at baseline and annually. For the New Cohort (median starting age = 12 months, n = 55), mean baseline SCT O2 was normal before starting hydroxyurea (mean 65%, 95% CI 58-72%) and significantly increased after two years (mean 72%, 95% CI 65-79%, p = 0.00001). The SCT O2 for patients receiving long-term hydroxyurea (median age = 9.6 years) was normal at study entry (mean 66%, 95% CI 58-74%) and remained stable across two years. Both cohorts had significantly higher SCT O2 than published data from predominantly untreated SCA patients. Cerebral oximetry is a non-invasive method to assess cerebrovascular pathology that complements conventional imaging. Our results indicate that hydroxyurea suggests protection against neurophysiologic changes seen in untreated SCA. This article is protected by copyright. All rights reserved.

BackgroundHigh-risk human papillomavirus (HPV) is a primary cause of an increasing number of oropharyngeal squamous cell carcinomas (OPSCCs). The viral etiology of these cancers provides the opportunity for antigen-directed therapies that are restricted in scope compared with cancers without viral components. However, specific virally-encoded epitopes and their corresponding immune responses are not fully defined.MethodsTo understand the OPSCC immune landscape, we conducted a comprehensive single-cell analysis of HPV16+ and HPV33+ primary tumors and metastatic lymph nodes. We used single-cell analysis with encoded peptide-human leukocyte antigen (HLA) tetramers to analyze HPV16+ and HPV33+ OPSCC tumors, characterizing the ex vivo cellular responses to HPV-derived antigens presented in major Class I and Class II HLA alleles.ResultsWe identified robust cytotoxic T-cell responses to HPV16 proteins E1 and E2 that were shared across multiple patients, particularly in HLA-A*01:01 and HLA-B*08:01. Responses to E2 were associated with loss of E2 expression in at least one tumor, indicating the functional capacity of these E2-recognizing T cells and many of these interactions validated in a functional assay. Conversely, cellular responses to E6 and E7 were limited in quantity and cytotoxic capacity, and tumor E6 and E7 expression persisted.ConclusionsThese data highlight antigenicity beyond HPV16 E6 and E7 and nominate candidates for antigen-directed therapies.

Background/Aims: Recruitment is often a barrier in clinical trials that include minoritized populations, such as individuals with sickle cell disease. In the United States, the majority of people with sickle cell disease identify as Black or African American. In sickle cell disease, 57% of the United States trials that ended early did so due to low enrollment. Thus, there is a need for interventions that improve trial enrollment in this population. After lower-than-expected recruitment during the first 6 months of the Engaging Parents of Children with Sickle Cell Anemia and their Providers in Shared-Decision-Making for Hydroxyurea trial, a multi-site study for young children with sickle cell disease, we collected data to understand barriers and used the Consolidated Framework for Implementation Research to categorize them and guide the development of targeted strategies. Methods: Study staff used screening logs and coordinator and principal investigator calls to identify recruitment barriers that were then mapped onto Consolidated Framework for Implementation Research constructs. Targeted strategies were implemented during Months 7–13. Recruitment and enrollment data were summarized before (Months 1–6) and during the implementation period (Months 7–13). Results: During the first 13 months, 60 caregivers ( M = 30.65 years; SD = 6.35) enrolled in the trial. Most caregivers primarily self-identified as female ( n = 54, 95%) and African American or Black ( n = 51, 90%). Recruitment barriers mapped onto three Consolidated Framework for Implementation Research constructs: (1) Process barriers (i.e. no identified “site champion” and poor recruitment planning at several sites); (2) Inner setting barriers (i.e. limited communication, low relative study priority at several sites); and (3) Outer setting barriers (i.e. poor patient attendance at clinic appointments). Targeted strategies to improve recruitment included (1) principal investigator site visits and retraining on recruitment procedures to address process barriers; (2) increased frequency of communication through all coordinator, site principal investigator, and individual site calls to address inner setting barriers; and (3) development and implementation of no-show procedures for clinic appointments to address outer setting barriers. After implementation of the recruitment strategies, the number of caregivers identified for pre-screening increased from 54 to 164, and enrollment more than tripled from 14 to 46 caregiver participants. Conclusion: Consolidated Framework for Implementation Research constructs guided the development of targeted strategies that increased enrollment. This reflective process reframes recruitment challenges as the responsibility of the research team rather than characterizing minoritized populations as “difficult” or “hard to reach.” Future trials including patients with sickle cell disease and minoritized populations may benefit from this approach.

Oxidative stress is an important contributor to the pathophysiology of sickle cell disease. The pathways involved are complex and interlinked. L-glutamine is an amino acid with myriad roles in the body, including the synthesis of antioxidants, such as reduced glutathione and the cofactors NAD(H) and NADP(H), as well as nitric oxide—so it has therapeutic potential as an antioxidant. However, the relative impact of L-glutamine on the redox environment in red blood cells in sickle cell disease is not fully understood, and there are few therapeutic trials in sickle cell disease. Following the FDA approval of L-glutamine for sickle cell disease, more research is still needed to understand its clinical effects and role in therapy.Impact statementL-glutamine has been recently approved by the FDA for the prevention of acute complications in sickle cell disease (SCD). However, there are many gaps in our understanding of the biologic role of glutamine and its therapeutic implications in SCD. This review summarizes the pre-clinical and clinical evidence that can inform clinical decision-making and future research on glutamine therapy in SCD patients.

Adolescents and young adults (AYA) with sickle cell disease (SCD) experience health challenges during the move from pediatric to adult care. Self-management (i.e., prioritizing and completing goals) and self-efficacy (i.e., confidence) are needed to manage a chronic disease effectively, but AYA with SCD often lack the skills. Mobile health (mHealth) technology (e.g., smartphones and tablets) present a way for AYA to monitor and track symptoms, change behaviors, and complete goals. We included a mHealth app into a group intervention (SCThrive) to see if using components of the app more frequently increased self-management and self-efficacy for AYA with SCD aged 13–21 years. We found that logging on to the app more often was related to better mood symptoms and lower pain ratings. AYA who logged onto the app more often reported more self-management skills and self-efficacy. Our findings indicate clinical benefits for those AYA with SCD who engaged with the mobile app., Sickle cell disease (SCD) is associated with significant health challenges that often worsen during adolescence. Living with SCD requires a substantial amount of self-management and mobile health (mHealth) holds considerable promise for assessing and changing behaviors to improve health outcomes. We integrated a mobile app as an adjunct to a group intervention (SCThrive) and hypothesized that more engagement with the mHealth app would increase self-management and self-efficacy for adolescents and young adults (AYA) with SCD. Twenty-six AYA ages 13–21 years (54% female; 46% HbSS genotype; all African-American/Black) received six weekly group sessions (three in-person, three online). Participants were provided with the mobile app (iManage for SCD) to record progress on their self-management goals and log pain and mood symptoms. The Transition Readiness Assessment Questionnaire (TRAQ-5) assessed self-management skills and the Patient Activation Measure (PAM-13) assessed self-efficacy at baseline and post-treatment. Logging on to the app more frequently was associated higher mood ratings (r = .54, CI[.18, .77], p = .006) and lower pain ratings (r = −.48, CI[−.77, −.02], p = .04). Regression analyses demonstrated that after controlling for scores at baseline, the number of logins to the app predicted self-management skills (p = .05, η2 = .17) and possibly self-efficacy (p = .08, η2 = .13). Our study findings indicate that it can be challenging to maintain engagement in mHealth for AYA with SCD, but for those who do engage, there are significant benefits related to self-management, self-efficacy, and managing pain and mood.

Purpose: Surgery often represents the best chance for disease control in locoregionally recurrent squamous cell carcinoma of the head and neck (SCCHN). We investigated dual immune-checkpoint inhibition [anti–PD-1, nivolumab (N), and anti-KIR, lirilumab (L)] before and after salvage surgery to improve disease-free survival (DFS). Patients and Methods: In this phase II study, patients received N (240 mg) + L (240 mg) 7 to 21 days before surgery, followed by six cycles of adjuvant N + L. Primary endpoint was 1-year DFS; secondary endpoints were safety, pre-op radiologic response, and overall survival (OS). Correlatives included tumor sequencing, PD-L1 scoring, and immunoprofiling. Results: Among 28 patients, the median age was 66, 86% were smokers; primary site: 9 oral cavity, 9 oropharynx, and 10 larynx/hypopharynx; 96% had prior radiation. There were no delays to surgery. Grade 3+ adverse events: 11%. At the time of surgery, 96% had stable disease radiologically, one had progression. Pathologic response to N + L was observed in 43% (12/28): 4/28 (14%) major (tumor viability, TV ≤ 10%) and 8/28 (29%) partial (TV ≤ 50%). PD-L1 combined positive score (CPS) at surgery was similar regardless of pathologic response (P = 0.71). Thirteen (46%) recurred (loco-regional = 10, distant = 3). Five of 28 (18%) had positive margins, 4 later recurred. At median follow-up of 22.8 months, 1-year DFS was 55.2% (95% CI, 34.8–71.7) and 1-year OS was 85.7% (95% CI, 66.3–94.4). Two-year DFS and OS were 64% and 80% among pathologic responders. Conclusions: (Neo)adjuvant N + L was well tolerated, with a 43% pathologic response rate. We observed favorable DFS and excellent 2-year OS among high-risk, previously treated patients exhibiting a pathologic response. Further evaluation of this strategy is warranted.

Background Sickle cell anemia (SCA) is a genetic blood disorder that puts children at a risk of serious medical complications, early morbidity and mortality, and high health care utilization. Until recently, hydroxyurea was the only disease-modifying treatment for this life-threatening disease and has remained the only option for children younger than 5 years. Evidence-based guidelines recommend using a shared decision-making (SDM) approach for offering hydroxyurea to children with SCA (HbSS or HbS/β0 thalassemia) aged as early as 9 months. However, the uptake remains suboptimal, likely because caregivers lack information about hydroxyurea and have concerns about its safety and potential long-term side effects. Moreover, clinicians do not routinely receive training or tools, especially those that provide medical evidence and consider caregivers’ preferences and values, to facilitate a shared discussion with caregivers. Objective The aim of this study is to understand how best to help parents of young children with sickle cell disease and their clinicians have a shared discussion about hydroxyurea (one that considers medical evidence and parent values and preferences). Methods We designed our study to compare the effectiveness of two methods for disseminating hydroxyurea guidelines to facilitate SDM: a clinician pocket guide (ie, usual care) and a clinician hydroxyurea SDM toolkit (H-SDM toolkit). Our primary outcomes are caregiver reports of decisional uncertainty and knowledge of hydroxyurea. The study also assesses the number of children (aged 0-5 years) who were offered and prescribed hydroxyurea and the resultant health outcomes. Results The Ethics Committee of the Cincinnati Children’s Hospital Medical Center approved this study in November 2017. As of February 2021, we have enrolled 120 caregiver participants. Conclusions The long-term objective of this study is to improve the quality of care for children with SCA. Using multicomponent dissemination methods developed in partnership with key stakeholders and designed to address barriers to high-quality care, caregivers of patients with SCA can make informed and shared decisions about their health. Trial Registration ClinicalTrials.gov NCT03442114; https://clinicaltrials.gov/ct2/show/NCT03442114 International Registered Report Identifier (IRRID) DERR1-10.2196/27650

Beginning early in childhood, patients with sickle cell disease (SCD) are at risk of life-threatening and debilitating health events. Despite the high morbidity and mortality of this disease, hematopoietic cell transplantation (HCT), a curative treatment for SCD, remains underutilized. In the literature there is a paucity of data concerning medical decision maker (MDM) awareness of HCT as a treatment option for SCD. The objective of this study was to estimate the proportion of parents/guardians of children with SCD who are aware of HCT as a treatment option, and to identify the demographic factors associated with knowledge of this therapy's curative potential. Between November 2015 and December 2016, 327 parents/guardians were surveyed across 4 clinical sites in 3 Midwestern US cities. Although 82% of parents/guardians had heard of HCT in the past and 78% were aware of the therapy's curative potential, nearly half indicated that they did not know whether HCT could specifically cure their child of the disease. Respondents who had discussed HCT with their child's physician had 5 times higher odds of being aware of HCT's curative potential than those who had not. These findings suggest that additional efforts to enhance MDM knowledge of HCT as well as shared decision making in the use of this therapy, is warranted.

BACKGROUND Without early initiation of disease-modifying therapy, the acute and chronic complications of sickle cell anemia (SCA) begin early in childhood and progress throughout life. Hydroxyurea is a safe and effective medication that reduces or prevents most SCA-related complications. Despite recommendations to prescribe hydroxyurea for all children with SCA as young as 9 months, utilization remains low. PROCEDURE We completed a retrospective review of hydroxyurea-prescribing practices and associated clinical outcomes at our institution over a 10-year period before and after the 2014 National Heart, Lung, and Blood Institute (NHLBI) recommendations to use hydroxyurea for all children with SCA. RESULTS Hydroxyurea use more than doubled within our pediatric SCA population from 43% in 2010 to 95% in 2019. The age of hydroxyurea initiation was significantly younger during 2014-2019 compared to 2010-2013 (median 2 years vs. 6 years, p ≤ .001). With this change in clinical practice, nearly all (69/71 = 97%) children born after 2013 received disease-modifying therapy by the end of 2019, primarily hydroxyurea (93%). Concurrently, the number of SCA-related admissions significantly decreased from 67/100 patient-years in 2010 to 39/100 patient-years in 2019 (p

Hydroxyurea (hydroxycarbamide) is an effective treatment for sickle cell anaemia (SCA), but clinical responses depend primarily upon the degree of fetal haemoglobin (HbF) induction and the heterogeneity of HbF expression across erythrocytes. The number and characteristics of HbF-containing cells (F-cells) are not assessed by traditional HbF measurements. Conventional hydroxyurea dosing (e.g. fixed doses or low starting doses with stepwise escalation) produces a moderate heterocellular HbF induction, but haemolysis and clinical complications continue. Robust, pancellular HbF induction is needed to minimise or fully inhibit polymerisation of sickle haemoglobin. We treated children with hydroxyurea using an individualised, pharmacokinetics-guided regimen starting at predicted maximum tolerated dose (MTD). We observed sustained HbF induction (mean >30%) for up to 6 years, which was not dependent on genetic determinants of HbF expression. Nearly 70% of patients had ≥80% F-cells (near-pancellular), and almost half had ≥90% F-cells (pancellular). The mean HbF/F-cell content was ~12 pg. Earlier age of initiation and better medication adherence were associated with high F-cell responses. In summary, early initiation of hydroxyurea using pharmacokinetics-guided starting doses at predicted MTD can achieve sustained near-pancellular or pancellular HbF expression and should be considered an achievable goal for children with SCA treated with hydroxyurea at optimal doses. Clinical trial registration number: NCT02286154 (clinicaltrials.gov).

BACKGROUND Sickle cell anemia (SCA) is a genetic blood disorder that puts children at a risk of serious medical complications, early morbidity and mortality, and high health care utilization. Until recently, hydroxyurea was the only disease-modifying treatment for this life-threatening disease and has remained the only option for children younger than 5 years. Evidence-based guidelines recommend using a shared decision-making (SDM) approach for offering hydroxyurea to children with SCA (HbSS or HbS/β0 thalassemia) aged as early as 9 months. However, the uptake remains suboptimal, likely because caregivers lack information about hydroxyurea and have concerns about its safety and potential long-term side effects. Moreover, clinicians do not routinely receive training or tools, especially those that provide medical evidence and consider caregivers’ preferences and values, to facilitate a shared discussion with caregivers. OBJECTIVE The aim of this study is to understand how best to help parents of young children with sickle cell disease and their clinicians have a shared discussion about hydroxyurea (one that considers medical evidence and parent values and preferences). METHODS We designed our study to compare the effectiveness of two methods for disseminating hydroxyurea guidelines to facilitate SDM: a clinician pocket guide (ie, usual care) and a clinician hydroxyurea SDM toolkit (H-SDM toolkit). Our primary outcomes are caregiver reports of decisional uncertainty and knowledge of hydroxyurea. The study also assesses the number of children (aged 0-5 years) who were offered and prescribed hydroxyurea and the resultant health outcomes. RESULTS The Ethics Committee of the Cincinnati Children’s Hospital Medical Center approved this study in November 2017. As of February 2021, we have enrolled 120 caregiver participants. CONCLUSIONS The long-term objective of this study is to improve the quality of care for children with SCA. Using multicomponent dissemination methods developed in partnership with key stakeholders and designed to address barriers to high-quality care, caregivers of patients with SCA can make informed and shared decisions about their health. CLINICALTRIAL ClinicalTrials.gov NCT03442114; https://clinicaltrials.gov/ct2/show/NCT03442114 INTERNATIONAL REGISTERED REPORT DERR1-10.2196/27650

Sickle cell anemia (SCA) is a hereditary hemoglobinopathy with a variable phenotype. There is no single biomarker that adequately predicts disease severity and can be used to monitor treatment response in patients in clinical trials and clinical care. The use of clinical outcomes, such as vaso-occlusive crises (VOC), requires long and expensive studies, sometimes with inconclusive results. To address these limitations, there are several biomarkers under study to improve the ability to predict complications and assess treatment response in both clinical and research settings. Oxygen gradient ektacytometry, also called as oxygenscan, is an assay that measures the effects of deoxygenation and reoxygenation on red blood cell (RBC) deformability and is gaining popularity in SCA research, because it captures the dynamic sickling capacity of a patient’s RBCs as they are subjected to an oxygen gradient under steady shear stress. We describe here the oxygenscan methodology and evaluate the correlation between oxygenscan parameters and more well-known biomarkers of SCA such as fetal hemoglobin (HbF), F-cells, and dense red blood cells (DRBCs). Our data indicate that the oxygenscan curve is affected by all these parameters and the result incorporates the effects of %HbF, %F-cells, RBC hydration, and RBC membrane deformability.

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

Increased extracellular volume (ECV) by CMR is a marker of interstitial myocardial fibrosis and is associated with diastolic dysfunction in sickle cell anemia (SCA). Left atrial (LA) dysfunction and stiffness contribute to the development of diastolic heart failure in other settings. We aimed to evaluate LA function and stiffness associations with ECV, tricuspid regurgitation jet velocity (TRV) and exercise abnormalities in SCA. In a prospective study, individuals with SCA underwent CMR, echocardiography and exercise test. ECV was measured using MOLLI sequence. Atrial strain was studied in the 4- and 2-chamber views. LA stiffness was calculated as the ratio of echocardiographic E/e’-to-LA reservoir strain. Twenty-four participants with SCA were included (median age 20 years). ECV was increased in participant with SCA compared to our lab normal values (mean 0.44 ± 0.08 vs 0.26 ± 0.02, P

Background Sickle cell disease (SCD) is associated with significant medical challenges that often worsen in adolescence when caregivers are beginning to transfer responsibility for disease management. Behavioral activation (BA) is an important precedent to improvements in self-management and ultimately health outcomes; however, few interventions targeting BA have been developed for the SCD population. The goal of the present study was to evaluate a technology-enhanced self-management intervention for adolescents and young adults (AYA) with SCD targeting BA domains (ie, disease knowledge, self-efficacy, motivation, and self-management skills). Design/methods Participants were randomized to one of two study arms. SCThrive participants (N = 26) completed six weekly group sessions, an in-person booster session, and used a companion app (iManage) to record symptoms, progress on goals, and connect with other group members. Each SCHealthEd participant (N = 27) received six weekly phone calls on SCD-related and general health education topics. All AYA completed questionnaires assessing BA at baseline and posttreatment. Results Separate mixed ANOVA analyses to assess for the effects of group (SCThrive/SCHealthEd), time (baseline/posttreatment), and group × time interaction indicated that there was a clinically meaningful improvement (8-point change) in self-efficacy, with a medium effect size, P = .09, η2 = .06, and there was statistically significant improvement in one self-management skill (tracking health), P = .001, d = .71, among SCThrive participants. Conclusions The results support the potential for a self-management intervention to improve self-efficacy in AYA with SCD. Health care providers are encouraged to target BA skills to support self-management of AYA with SCD.

In 2017, the Food and Drug Administration approved 2 medications for sickle cell anemia (SCA): hydroxyurea for children and l-glutamine for children and adults. The approval of hydroxyurea was long overdue, but the approval of l-glutamine was a surprise to many. Any effective new treatment for SCA is a welcome advance, but there are few published studies of l-glutamine as a specific treatment for SCA. Accordingly, there are many unanswered questions about its efficacy, safety, and role in current therapy.

The purpose of this study is determine if both liver T2* and cardiac T2* can be measured on a single breath-hold acquisition. For this IRB-approved retrospective study, 137 patients with dedicated Cardiac MRI and Liver MRI examinations obtained sequentially on 1.5T scanners and on the same day were included for analysis. Both the cardiac and liver MRI examinations utilized GRE sequences for quantification of tissue iron. Specifically, T2* was measured using an 8-echo, multi-echo gradient echo single breath-hold sequence. Liver T2* was measured in a blinded manner on images from each of the cardiac and dedicated liver MRI examinations and were correlated. Bland–Altman difference plot was used to assess mean bias. 137 examinations from 93 subjects met inclusion criteria. 10 examination pairs were excluded because the first echo time (TE) on the cardiac MRI was insufficiently short for the very high liver iron content. After exclusion, 127 studies from 89 subjects (67.4% males) were included in the final analysis. The mean subject age (± standard deviation) was 11.5 ± 7.5 years (range 0–29.3 years; median 10.5 years). Mean liver T2* measured on cardiac MRI was 8.3 ± 7.7 ms and mean liver T2* measured on dedicated liver MRI was 7.8 ± 7.4 ms (p

The thalassemias are genetically complex and usually autosomal recessive. We describe 5 unrelated individuals with non-transfusion-dependent β-thalassemia (NTDT), some with apparently dominant transmission, because of a single β-thalassemia mutation coinherited with a triplicated α-globin locus. Each had an initial, incorrect diagnosis of β-thalassemia trait. The correct diagnosis of NTDT was made at a mean of 7 years of age. Despite reports of this compound genotype causing NTDT, it remains unfamiliar to many clinicians. To increase awareness, we highlight its varied and sometimes subtle clinical and laboratory features and the need for comprehensive genetic testing for timely and correct diagnosis.

Background: Hydroxyurea (HU) is the primary medication used to prevent the significant medical and neurologic morbidities of pediatric sickle cell disease (SCD; HbSS or HbSB0 thalassemia). Despite the benefits of HU, it remains under-utilized likely due to lack of clinician knowledge/training and negative caregiver perceptions. Thus, we developed the Engage-HU randomized controlled trial (NCT03442114) as a novel approach to address HU utilization barriers. Engage-HU is designed to assess how clinicians can engage caregivers in a shared discussion that considers their values, preferences, and scientific evidence about HU. The COVID-19 pandemic has resulted in significant changes to healthcare delivery for children with SCD, as they are at increased risk of severe illness from COVID-19 infection. Given their risk status, it was recommended that patients with SCD complete telehealth visits when possible. Some families also chose to delay care because they feared their child would get infected at hospitals/healthcare clinics that care for COVID-19 positive patients. Since the lives of all families enrolled in the Engage-HU trial have been affected to some extent, we incorporated measures to capture the impact of the COVID-19 pandemic and the usability of telemedicine implementation and services. Methods: Engage-HU is a randomized control trial comparing two dissemination methods for clinicians to facilitate shared decision-making with caregivers of young children with SCD. Study outcomes include caregiver confidence in decision-making and perceptions of experiencing shared decision-making as well as HU uptake and child health outcomes. Eligible children are 0 to 5 years, candidates for HU, and their caregiver has not decided about HU in the past 3 months. The trial is being conducted at 9 sites in the United States and uses a unidirectional crossover design. The primary endpoints are caregiver decisional uncertainty and caregiver perception of shared decision-making measured using validated tools. Data will be analyzed using the intent-to-treat principle, and all participants will remain in the arm to which they were randomized. A multiple group comparison analysis will be performed to assess significant response variable differences by group randomization. The Engage-HU study aims to recruit 174 caregivers who are considering initiating HU. The trial is being conducted at 9 sites in the United States. Data collection is ongoing, and 160 caregiver-participants have been enrolled to date. Since May 2020, caregiver-participants have completed the COVID-19 Exposure and Family Impact Scales (CEFIS), which contain 2 subscales (exposure to potentially traumatic aspects of the pandemic, impact on families), and the COVID-19 telemedicine use survey during a study visit. Results: Currently, 8 of the 9 sites have collected data from 48 caregivers (93.8% mothers), most of whom (93.8%) identify as African American/Black (see Figure 1). Correlations indicated that older caregivers experienced greater exposure (Mean = 7.0, SD = 4.1, range = 1-19) to potentially traumatic aspects of the pandemic (r = .31, p = .04). Distress related to COVID-19 varied widely across the sample, for both caregivers (Mean = 5.9, SD = 2.9, range = 1-10) and children (Mean = 4.1, SD = 3.4, range = 1-10). Scores on the telemedicine usability survey were generally high, indicating that caregivers are happy with the quality of care delivered via telehealth. However, caregivers (r = .30, p = .09) and children (r = .32, p = .07) experiencing more pandemic-related distress reported less satisfaction with telehealth. Conclusion: Although Engage-HU has resumed research operations, recruitment has not reached pre-pandemic targets, as fewer eligible patients are scheduled for routine care visits at SCD clinics. Our preliminary analyses suggest a significant continued impact of the pandemic on families and general satisfaction with the quality of healthcare delivered via telemedicine. These findings indicate that targeted screenings to identify and intervene for those who demonstrate more COVID-19 pandemic-related distress are needed. Figure 1 Figure 1. Disclosures Quinn: Forma Therapeutics: Consultancy; Aruvant: Research Funding; Novo Nordisk: Consultancy; Emmaus Medical: Research Funding. Yates: Agios Pharmaceuticals: Current Employment. Badawy: Sanofi Genzyme: Consultancy; Vertex Pharmaceuticals Inc: Consultancy; Bluebird Bio Inc: Consultancy. Thompson: bluebird bio, Inc.: Consultancy, Research Funding; Baxalta: Research Funding; Biomarin: Research Funding; Celgene/BMS: Consultancy, Research Funding; CRISPR Therapeutics: Research Funding; Vertex: Research Funding; Editas: Research Funding; Graphite Bio: Research Funding; Novartis: Research Funding; Agios: Consultancy; Beam: Consultancy; Global Blood Therapeutics: Current equity holder in publicly-traded company. Smith-Whitley: Global Blood Therapeutics: Current Employment. King: National Cancer Institute: Research Funding; National Heart, Lung, and Blood Institute: Research Funding; Health Resources and Services Administration: Research Funding; Global Blood Therapeutics: Research Funding. Meier: CVS Caremark: Consultancy; Forma Therapeutic: Membership on an entity's Board of Directors or advisory committees; NovoNordisk: Membership on an entity's Board of Directors or advisory committees; Novartis,: Other: Data Safety Monitoring Board membership; NHLBI: Other: Data Safety Monitoring Board membership; Global Blood Therapeutics: Other: Steering Committee membership, grant funding; CDC,: Other: grant funding; Indiana Department of Health: Other: grant funding . Tubman: Global Blood Therapeutics: Consultancy, Research Funding; Novartis Pharmaceuticals: Honoraria, Research Funding; Forma Pharmaceuticals: Consultancy; Perkin Elmer: Honoraria. Crosby: Forma Therapeutics: Honoraria; PCORI: Research Funding; HRSA: Research Funding; Global Blood Therapeutics Panel: Honoraria; Children's Hospital of Philadelphia: Honoraria; Professional Resource Exchange: Patents & Royalties: $30-$60 every other year; SCDAA: Honoraria; NHLBI: Other: Payment for review of LRP Proposals, Research Funding. OffLabel Disclosure: Hydroxyurea has been FDA approved for the treatment of sickle cell disease for patients ages 2 years and above but NHLBI and ASH Guidelines recommend it be offered to children as young as age 9 months.

Introduction: Sickle cell disease (SCD) is a genetic red blood cell (RBC) disorder that causes chronic hemolytic anemia, progressive organ damage, and life-threatening acute complications such as painful vaso-occlusive crises. Allogeneic hematopoietic stem cell transplant (allo-HSCT) with myeloablative conditioning remains the only curative therapy for SCD but has several limitations including low donor availability and conditioning-related toxicity. Genetic modification of autologous hematopoietic system cells (HSCs) with reduced-intensity conditioning (RIC) using a high-potency drug product may address these limitations. ARU-1801 is a gene therapy that uses a modified γ-globin lentiviral vector to produce HbF G16D within autologous CD34+ HSCs. Preclinical studies in SCD mice have shown the G16D mutation enables γ-globin G16D to bind α-globin with higher affinity; lentiviral transfer of γ-globin G16D resulted in 1.5-2x more HbF per vector copy number (VCN) compared to analogous wild-type γ-globin vector. Early studies also suggested HbF G16D may be more potent for anti-sickling than HbF, lowering reticulocyte counts in SCD mice to a greater extent at similar protein levels. We hypothesize ARU-1801 with RIC could lessen toxicities and resource utilization relative to myeloablative approaches, allowing expanded access to gene therapy for a broader group of SCD patients. Updated data from patients in the ongoing Phase 1/2 study (NCT02186418) including laboratory and clinical markers of efficacy are presented here. Methods: Adults (18-45 years old) with severe SCD (defined by recurrent vaso-occlusive events [VOE] and acute chest syndrome) were screened for eligibility. Prior to ARU-1801 drug product (DP) infusion, all patients received a single IV dose of RIC melphalan (140 mg/m 2). Endpoints included measures of safety, engraftment, VCN, hemoglobin sub-fractions, and SCD-related outcomes. Patients were weaned off transfusions 3-6 months after DP infusion. Levels of anti-sickling globins (including HbF G16D) are presented as proportions of non-transfused total hemoglobin. Results: As of 28 July 2021, four patients (mean, 26 [19-35] years old) have been treated with ARU-1801 gene therapy for SCD with three patients followed for ≥12 months post-transplant. Transient neutropenia and thrombocytopenia were the predominant adverse events, lasting a median seven days each. There have been no other serious adverse events related to chemotherapy or ARU-1801 to date. At 36 months post-transplant, Patient 1 has shown stable HbF expression (27%) and 64% F-cells. Patient 2 has maintained 14% HbF and 37% F-cells at 36 months despite lower engraftment of ARU-1801 due to renal hyperfiltration (eGFR = 200 mL/min/1.73 m 2) at time of conditioning, which resulted in lower melphalan exposure. Both patients saw marked improvements in SCD manifestations, including 93% and 85% fewer annualized VOEs, respectively, in the two years after receiving ARU-1801 gene therapy compared to two years prior. Patient 3 received ARU-1801 manufactured with several process modifications (including improvements of HSC collection timing and lentiviral production) and has maintained 36% HbF at month 15 with pancellular distribution (96% F-cells). To date, Patient 3 has had no VOEs since ARU-1801 administration, representing 100% reduction from baseline. Conclusion: Amelioration of SCD phenotype and engraftment of ARU-1801 gene-modified HSCs is possible with a single RIC dose of melphalan, as demonstrated in three patients. The first patient shows 27% HbF expression at three years, and 93% reduction in VOEs. The second patient had lower HSC engraftment due to below-target melphalan exposure (likely caused by renal hyperfiltration), with 14% HbF and 5% HbA2 at three years. Nonetheless, an 85% reduction in VOEs in Patient 2 demonstrates significant clinical benefit. Dose-adjusted melphalan has the potential to improve engraftment in SCD patients with renal hyperfiltration. Following manufacturing process improvements, the third patient has shown the highest HbF (36%) at one year, the highest F-cells (96%), and no VOEs since receiving ARU-1801. ARU-1801, with RIC melphalan conditioning, is a promising alternative to myeloablative transplants for achieving durable responses with a favorable safety profile in patients with severe SCD. Longer follow-up and additional patients will be presented. Figure 1 Figure 1. Disclosures Asnani: Avicanna Ltd.: Research Funding; Aruvant Sciences: Research Funding. Lutzko: Aruvant Sciences: Patents & Royalties: preclinical vector development. Quinn: Forma Therapeutics: Consultancy; Emmaus Medical: Research Funding; Novo Nordisk: Consultancy; Aruvant: Research Funding. Lo: Aruvant Sciences: Current Employment. Little: Aruvant Sciences: Current Employment. Dong: Aruvant Sciences: Current Employment. Malik: Aruvant Sciences: Consultancy; Forma Therapeutics: Consultancy; Aruvant Sciences: Patents & Royalties; CSL Behring: Patents & Royalties. OffLabel Disclosure: Plerixafor was used for stem cell mobilization. Melphalan was used as chemotherapy conditioning prior to autologous transplant with ARU-1801

Introduction: L-glutamine (Endari ®, Emmaus Medical, Inc.) is an amino acid approved for the treatment of sickle cell disease (SCD) by the United States Food and Drug Association (FDA) after 2 clinical trials demonstrated a reduction in painful episodes and hospitalizations. L-glutamine has many roles, including de novo synthesis of intracellular glutathione that may protect sickle erythrocytes from oxidant injury. Despite its licensure, the pharmacokinetics (PK) of multi-dose oral L-glutamine for SCD have not been studied. Methods: We conducted a dose-escalation PK trial from January to June 2021 (NCT04684381) on 3 cohorts with 4 participants each: pediatric SCD patients (0 - 18 y, cohort 1), adult SCD patients (>18 y, cohort 2), and adult healthy volunteers (>18 y, cohort 3). There were 4 weekly study visits to assess 3 ascending dose levels (Figure 1). For each visit, participants arrived in the research clinic after an overnight fast. Plasma L-glutamine and other amino acid levels were obtained before and after oral L-glutamine doses at each visit and quantified by ion exchange chromatography. On study visit 1, a dose of 0.1 g/kg of L-glutamine was administered and amino acids were measured at 30±5, 60±10, 120±15, 180±15 and 240±20 minutes after the dose. The procedure was repeated in the afternoon after a standardized meal. On study visit 2, the dose was increased to 0.3 g/kg twice daily (approximate FDA-approved dosing). On study visit 3, a single oral dose of 0.6 g/kg (once daily dosing) was given for fasting PK levels, and on study visit 4 the 0.6 g/kg dose was given with a standardized meal. After the first 3 study visits, participants continued L-glutamine at the corresponding dose level at home and completed a daily phone survey to document adherence and adverse events. Results: Baseline characteristics are summarized in Table 1. Baseline L-glutamine levels similar across the three study cohorts (Table 1). One participant from cohort 1 withdrew during study visit 1 and was replaced. Another participant from cohort 2 was withdrawn due to hospitalization for severe anemia and was replaced. One participant from cohort 3 did not complete visit 4 due to dyspepsia. Non-compartmental PK analysis (NCA) was conducted using Phoenix WinNonlin® Professional Version 8.4 (Certara, NJ, US; Figure 2). After oral administration, L-glutamine plasma levels peaked (T max) at an average (mean ± SD) of 1.2 ± 0.9 hours. Compared to doses 0.1 g/kg and 0.3 g/kg, the T max was later for 0.6 g/kg (p The most common grade 2 adverse events were dyspepsia and headache (3 instances each). There was no significant elevation in ammonia levels, and plasma concentrations of the metabolite L-glutamate was similar to L-glutamine (Figure 2). Conclusions: This is the first multi-dose PK study of L-glutamine (Endari) for SCD. Daily dosing was overall well-tolerated, with rapid absorption of 0.1 and 0.3 g/kg doses and no drug accumulation. The highest 0.6 g/kg dose was limited by palatability and featured slower and saturable absorption, so further dose escalation is likely not feasible. Ongoing analyses include possible food-drug interactions and PK-pharmacodynamic (PK-PD) studies to identify salutary effects on erythrocytes. Our findings will help inform the proper dosing of L-glutamine for patients with SCD, and potentially permit individualized PK-guided dosing to maximize treatment benefits. This was an investigator-initiated trial funded by Emmaus Medical, Inc. Figure 1 Figure 1. Disclosures Sadaf: Emmaus Medical, Inc: Research Funding. Ware: Bristol Myers Squibb: Research Funding; Addmedica: Research Funding; Hemex Health: Research Funding; Nova Laboratories: Research Funding; Novartis: Other: DSMB Chair; Editas: Other: DSMB Chair. Quinn: Emmaus Medical: Research Funding; Novo Nordisk: Consultancy; Aruvant: Research Funding; Forma Therapeutics: Consultancy. OffLabel Disclosure: Endari (L-glutamine) is FDA approved for the treatment of Sickle Cell Disease at a dose of 0.3 g/kg. However, in our pharmacokinetic study we tested doses 0.1, 0.3 and 0.6 g/kg.

Reticuloendothelial system MRI signal hypointensity is common in pediatric oncology patients with solid abdominal tumors. To assess changes in liver, spleen and bone marrow T2-weighted MRI signal intensity over time and their relationship to blood transfusion history in children with solid abdominal tumors. In this retrospective study we measured liver, spleen and bone marrow signal intensity on axial T2-weighted MR images obtained December 2009 through February 2016 in children with hepatoblastoma, neuroblastoma, ganglioneuroblastoma and Wilms tumor. All signal intensity measurements were normalized to paraspinal muscle signal intensity. We used linear mixed models (including a day*day quadratic term) to determine whether organ signal intensity changed over time and whether change was associated with blood transfusion volume or tumor type. We included 133 children (mean age at diagnosis =2.9 years); 56 had neuroblastoma, 42 hepatoblastoma, 28 Wilms tumor and 7 ganglioneuroblastoma. Seventy-nine (59.4%) children received transfusions (median: 8 transfusions, range: 1–30; mean volume: 1,148.5 mL). Hepatic, splenic and bone marrow signal intensity ratios changed quadratically over time for the study population, initially decreasing and then increasing (P

Introduction: Hydroxyurea has well-described clinical and laboratory benefits in sickle cell anemia (SCA). Traditionally, hemoglobin concentration (Hb) and fetal hemoglobin (HbF) are used to assess treatment response, but these aggregate parameters do not fully capture the range of erythrocyte abnormalities in SCA. Dense red blood cells (DRBCs) are defined as RBCs with density >1.11 g/mL as measured by density-gradient fractionation methods, which are tedious and require technical expertise. This subpopulation of dehydrated RBCs has been associated with increased SCA severity but has not been extensively studied in children. Here we describe the utility of rapid, automated DRBC quantitation and show that the percent of DRBCs (%DRBCs) is a robust biomarker of hydroxyurea response in children with SCA. Methods: The Therapeutic Response Evaluation and Adherence Trial (TREAT, NCT02286154) was a single-center prospective study that demonstrated individualized, pharmacokinetic (PK)-guided hydroxyurea dosing in young patients (mean age 12.1 months at initiation) results in robust and sustained HbF levels >30-40% for most adherent patients. The longitudinal follow-up phase of TREAT aims to comprehensively evaluate hematologic parameters and organ function to demonstrate the long-term benefits of this treatment strategy. During clinic visits (every 3-6 months), TREAT participants had complete blood counts (CBCs) with the ADVIA® 2120i system. This automated analyzer quantifies hyperchromic RBCs within seconds by directly measuring cell hemoglobin concentration, where DRBCs are known to correspond to RBCs with a measured MCHC >41 g/dL. Data were analyzed at baseline and after at least 6 months of hydroxyurea therapy (M≥6). α- and β-globin genotypes were determined for all patients. Results: Thirty-three TREAT participants had ADVIA data available for analysis (Table). All had homozygous SCA except one with sickle-β0-thalasemia; 17 (51.5%) were male. The median age at hydroxyurea initiation was 10.3 months (mean 26.1 months; range 6 months - 17 years). The median duration of hydroxyurea therapy was 27.7 months (mean 31.5). At baseline, median %DRBCs was 2.1%. Baseline %DRBCs were directly correlated with age at initiation of hydroxyurea (p=0.022) and inversely correlated with baseline HbF (p=0.001). After initiation of hydroxyurea (M≥6), there was a 47.6% reduction in %DRBCs (p=0.001). Median %DRBCs at M≥6 was directly correlated with absolute reticulocyte (ARC) (p=0.002), absolute neutrophil (ANC) (p=0.003) and platelet counts (p Conclusions: DRBCs can be rapidly quantified without the tedium of classical density-gradient fractionation methods using the automated ADVIA 2120i hematology analyzer, which directly measures hyperchromic RBCs. These data from TREAT demonstrate the feasibility of serial %DRBC measurements in clinical trials and clinical practice. TREAT participants had low baseline DRBCs compared to untreated adult SCA patients (reported mean ≈12%), reflecting the young age of these patients. Nevertheless, there was a significant decline in %DRBCs with treatment that correlated strongly with the known laboratory benefits of hydroxyurea. In conclusion, automated DRBC measurements are a robust biomarker that can be incorporated in a panel of laboratory measurements of response to hydroxyurea (and severity of SCA). A larger, multicenter study of PK-guided hydroxyurea therapy (HOPS, NCT03789591) is currently underway in 11 US sickle cell centers and will provide generalizable data on DRBC responses with optimal hydroxyurea therapy. Disclosures Malik: Aruvant Sciences, Forma Therapeutics, Inc.: Consultancy; Aruvant Sciences, CSL Behring: Patents & Royalties. Kalfa:Agios Pharmaceuticals, Inc: Consultancy, Research Funding; Forma Therapeutics, Inc: Research Funding.

Background: Sickle cell disease (SCD) is associated with medical challenges that often worsen for adolescents and young adults (AYA) when caregivers begin to transfer responsibility for care. Living with SCD requires self-management and self-efficacy and is a critical concern for AYA as they navigate complex medical systems. However, previous research indicates that AYA with SCD often lack the ability, confidence, and skills to manage their disease effectively. As most AYA with SCD are now "technology natives," mobile health (mHealth) holds considerable promise for assessing and changing behaviors to improve health outcomes. In a previous feasibility and acceptability study, AYA with SCD provided qualitative feedback that they would use mHealth (a co-designed mobile app) and that it was beneficial for tracking health behaviors. Thus, we integrated the mHealth app into a group intervention (SCThrive) and hypothesized that more engagement with the mHealth app would result in increased self-management and self-efficacy for AYA with SCD. Methods: Our analysis from a single-site, randomized control trial (NCT02851615) assessed data from only AYA in the treatment arm (N = 26) who received the SCThrive intervention and used the mHealth app. The sample included AYA with SCD aged 13 to 21 years (Mage = 16.7 years; 54% female; 46% HbSS genotype; all African American/Black) who received six-weekly group sessions (3 in-person, 3 online). All SCThrive participants were provided with the mobile app (iManage) on an iPad. The Transition Readiness Assessment Questionnaire (TRAQ-5) assessed self-management skills and the Patient Activation Measure (PAM-13) assessed self-efficacy at baseline and posttreatment. We also assessed engagement (logins), confidence and completion of self-management goals (e.g., exercising, take medications), pain diary entries, and mood symptoms recorded on the iManage app (see Figure 1). Results: Preliminary analyses indicated that most AYA with SCD logged on to the iManage app (Mlogins = 7.8, SD = 9.1, range = 1 - 45) and viewed their pain diary (Mviews = 5.7, SD = 9.1, range = 1 - 45) at least once a week. Eighty-eight percent of AYA saved a pain diary entry and the most commonly used strategies for managing pain episodes were resting (22%), drinking water (19%), and using distraction (8%). AYA viewed their self-management goals about once every 11 days (Mdays = 11.24, SD = 13, range = 0 - 57). All AYA created (Mgoals = 5.7, SD = .72, range = 4 - 7), but only 54% of AYA completed at least one self-management goal. Of the 149 self-management goals created by the entire sample, only 37 (25%) were recorded as completed. AYA with a confidence level of 7 or lower were least likely to complete their self-management goals (14%) (see Figure 2). Correlation analyses demonstrated that logging on to the iManage app more frequently was associated with completing more self-management goals (r = .38), documenting pain symptoms more frequently (r = .54), and lower mood ratings (r = .54). Primary analyses demonstrated that after controlling for scores at baseline, the number of logins to the iManage app (p = .08, η2 = .13) predicted self-efficacy (PAM-13) and (p = .05, η2 = .17) self-management skills (TRAQ-5). Completing more self-management goals on the iManage app did not predict scores on the PAM-13, but, surprisingly, predicted lower scores (less self-management) on the TRAQ-5 (p = .08, η2 = .14). Conclusion: Lessons learned from our study indicate that it can be challenging to maintain engagement in mHealth for AYA with SCD, but for those who do engage there are significant benefits related to self-management goals, documenting pain symptoms, and mood. Supporting hypotheses, engaging more with the iManage app was related to higher-reported self-efficacy and self-management skills. Some AYA engaged with the app infrequently and did not create or complete self-management goals; others were "super users" and logged into the app daily. Increasing the frequency of reminder messages, encouraging more interactions with peers, and tailoring the opportunity to earn incentives are potential modifications for future interventions. However, our findings indicate that a mHealth app can be effectively integrated into a clinical trial and is related to positive outcomes. Although there are challenges to address, mHealth has the potential to bring about changes in behavior and improve health in the SCD population. Disclosures No relevant conflicts of interest to declare.

Introduction: ARU-1801 is a gene therapy consisting of autologous CD34+ hematopoietic stem cells and progenitors (HSCPs) transduced with a lentiviral vector (LV) encoding a modified γ-globinG16D gene. Preclinical studies in SCD mice have shown that g-globinG16D binds α-globin with higher affinity; hence, the g-globinG16D LV produces 1.5-2x more HbF/vector copy number (VCN) than a g-globin LV. Preliminary studies also show greater reduction in reticulocytes in SCD mice expressing HbFG16D compared to those expressing the same level of HbF, suggesting that HbFG16D may have a more potent anti-sickling effect than HbF. We hypothesized a high potency anti-sickling globin would allow ARU-1801 to be effective with reduced intensity conditioning (RIC). RIC would result in lower toxicities and resource utilization compared to myeloablative approaches, allowing access of gene therapy to a broader group of SCD patients. We previously reported early data from patient 1 (P1) and 2 (P2) in the ongoing Phase 1/2 study (NCT02186418), who were treated with drug product (DP) from the initial ARU-1801 manufacturing process (Process I). We now present the long-term data on these patients and early data from P3, the first patient treated with our new manufacturing process (Process II). Methods: Adults with severe SCD, as defined by recurrent vaso-occlusive events (VOE) and acute chest syndrome deemed eligible were enrolled. Manufacturing process improvements in Process II included optimized timing of HSCP collection after plerixafor mobilization, LV production and improved HSCP transduction. Prior to DP infusion, all patients received a single dose of IV melphalan (140 mg/m2 BSA) and were weaned off transfusions 3-6 months after DP infusion. Patients were monitored for safety, engraftment, VCN, anti-sickling Hb (ASG) expression, and hematological and clinical manifestations of SCD. Levels of ASG (including HbFG16D) are presented as fractions of endogenous Hb. Results: As of 28 July 2020, data from 3 patients treated with ARU-1801 are available. P1 (34yr old) has HbSβ0- and P2 (24yr old) has HbSβ+ thalassemia (2-3% HbA). Both have 30 months (mo) post-transplant (PT) follow up. P3 (19yr old) has HbSS genotype with 6 mo PT follow up. ARU-1801 demonstrated a favorable safety profile with no treatment-related adverse events to date. Time to neutrophil engraftment (ANC ≥500) was 9, 7, and 7 days PT, and time to platelet recovery (Plt >50,000) was 12, 7, and 6 days PT, in P1, P2, and P3, respectively. Figure 1 shows HSPC dose, conditioning exposure and gene transfer; Figure 2 shows ASG over time. Using Process I, P1 has shown stable expression of 20% HbFG16D, 31% ASG and 31%à64% F-cells over 2.5 years, despite a low DP VCN of 0.2 and low HSPC dose of 1.4 x106 cell/kg. P2 received a higher cell dose of 7.1 x106 cell/kg with a DP VCN of 0.47 but had below target melphalan exposure, likely due to rapid clearance from hyperfiltration (GFR= 200 mL/min/1.73m2). Despite lower engraftment and HbFG16D level, P2 maintains stable total ASG of 22% at 30 mo due to a compensatory increase in HbF. Using Process II, P3 received DP of 6.8 x106 cells/kg with a VCN of 1.0, and demonstrated an engrafted VCN of 0.74, 71% F-cells and 91% F-reticulocytes at 6 mo. As P3 is being weaned off transfusions, HbFG16D is progressively rising, showing the selective advantage to HbFG16D-containing RBCs. P1 and P2 have maintained improvements in VOEs, no VOE in P3 so far (data will be presented). Conclusion: We show that engraftment of ARU-1801 and amelioration of disease is possible with RIC using IV melphalan, with persistent stable ASG expression and meaningful improvement in VOEs in P1 and P2. P1 shows stable HbFG16D and high ASG despite low, albeit stable VCN. P2 had lower HSCP engraftment, which we hypothesize was due to below target melphalan exposure. Nevertheless, significant clinical benefit was observed in P2 due to stable ASG of 22% at mo 30. It is likely that the presence of this amount of HbFG16D has provided enough ASG to prevent sickling/ineffective erythropoiesis, resulting in the preferential survival of HbF+HbFG16D-expressing RBC. Process II DP in P3 resulted in 2-4X higher engraftment of transduced HSCPs at 6 mo. Additional process enhancements are under development for future treated patients. ARU-1801, administered with RIC, holds significant promise for achieving durable responses with a favorable safety profile in patients with severe SCD. Disclosures Asnani: Aruvant Sciences: Research Funding; Avicanna Ltd.: Research Funding. Lutzko:Aruvant Sciences: Patents & Royalties: pre-clinical vector development. Lo:Aruvant Sciences: Current Employment. Little:Aruvant Sciences: Current Employment. McIntosh:Aruvant: Current Employment, Current equity holder in private company. Malik:Aruvant Sciences, Forma Therapeutics, Inc.: Consultancy; Aruvant Sciences, CSL Behring: Patents & Royalties. OffLabel Disclosure: Plerixafor - stem cell mobiliziation Melphalan - chemotherapy conditioning pre autologous transplant with ARU-1801