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Key Points HMB is associated with rare and common variants in genes related to anemias and bleeding disorders.These are the first exome-sequencing results from patients with HMB, as well as their comparison with control exomes., Visual Abstract, Adolescents with low von Willebrand factor (VWF) levels and heavy menstrual bleeding (HMB) experience significant morbidity. There is a need to better characterize these patients genetically and improve our understanding of the pathophysiology of bleeding. We performed whole-exome sequencing on 86 postmenarchal patients diagnosed with low VWF levels (30-50 IU/dL) and HMB and compared them with 660 in-house controls. We compared the number of rare stop-gain/stop-loss and rare ClinVar “pathogenic” variants between cases and controls, as well as performed gene burden and gene-set burden analyses. We found an enrichment in cases of rare stop-gain/stop-loss variants in genes involved in bleeding disorders and an enrichment of rare ClinVar “pathogenic” variants in genes involved in anemias. The 2 most significant genes in the gene burden analysis, CFB and DNASE2, are associated with atypical hemolytic uremia and severe anemia, respectively. VWF also surpassed exome-wide significance in the gene burden analysis (P = 7.31 × 10−6). Gene-set burden analysis revealed an enrichment of rare nonsynonymous variants in cases in several hematologically relevant pathways. Further, common variants in FERMT2, a gene involved in the regulation of hemostasis and angiogenesis, surpassed genome-wide significance. We demonstrate that adolescents with HMB and low VWF have an excess of rare nonsynonymous and pathogenic variants in genes involved in bleeding disorders and anemia. Variants of variable penetrance in these genes may contribute to the spectrum of phenotypes observed in patients with HMB and could partially explain the bleeding phenotype. By identifying patients with HMB who possess these variants, we may be able to improve risk stratification and patient outcomes.

Vascular surgery fellowship applications among general surgery residents have declined. Given this steady downward trend in vascular applicants in conjunction with a predicted critical shortage of vascular surgeons, a call to action for increased recruitment is needed. To improve recruitment efforts, a subgroup analysis of general surgery residents was performed to explore factors that influence interest in vascular surgery.A cross-sectional national survey of residents (n = 467) was conducted from September 2016 to May 2017. In addition to collection of demographic and occupational characteristics, assessment of psychological, work-life balance, and job-satisfaction variables were obtained. Residents were grouped based on their interest in pursuing a fellowship. Chi-squared and Fisher's exact test was performed to determine significant variables.Residents were grouped into "interest in non-vascular fellowship" (n = 350), "interest in vascular fellowship" (n = 21), and "not interested in fellowship" (n = 96). Significant variables between the groups included age, geographic location, residency size, and type of institution (p0.05). Those interested in vascular surgery tended to be older. Residents not interested in fellowship were more commonly located in the Midwest and at smaller, community residencies. No significant difference was found between mental wellness and work-life balance variables. Those residents interested in a vascular surgery fellowship were more dissatisfied with their current salary as compared to other residents (p = 0.021).There is a predicted critical shortage in the vascular surgery workforce making recruitment of the best and brightest residents into the specialty vital to its future. In order to invigorate and broaden our group of vascular surgeons, focused recruitment of younger, Midwest, general surgery residents at smaller, community programs may provide the most yield. Publicizing the strengths of a vascular surgery career including the diversity of patients, continuity of care, proficiency in technical skill, and higher monetary rewards should be emphasized in recruiting these target populations.

Background Transfusions are a common intervention within pediatrics and require unique considerations to optimize patient care. Poor knowledge of evidence-based transfusion practice can lead to misuse of transfusion therapy and harm. While there have been assessments of transfusion medicine knowledge of physicians caring for adult patients, there is little data regarding pediatricians. Study design and methods Using a published transfusion medicine knowledge exam for internal medicine physicians as a backbone, pediatric transfusion medicine experts, using an iterative process, developed a pediatric-specific examination. Pilot testing and Rasch analysis, a method used in high-stakes testing, was used to validate the exam. The exam and a previously validated survey on transfusion medicine training, attitudes, and perceived ability were administered to pediatric residents. Analysis consisted of descriptive statistics as well as comparisons of exam scores based on survey responses. Results 330 pediatric residents from 19 sites in 6 countries participated in the study. The vast majority (91%) of residents had obtained blood product consent. The mean exam score was 37.1% (range 9.5%-71.4%) with no statistical differences based on amount or perceived quality of transfusion medicine education or perceived ability. Discussion A rigorously validated exam has now been developed that can be used to assess pediatric transfusion medicine knowledge. A large international group of pediatric residents performed poorly on the exam demonstrating a pressing need for improved transfusion medicine education to ensure safe and appropriate administration of blood components to infants and children.

Objectives The aim of this pilot study was to compare the quality of sedation and ease of intravenous (IV) catheter placement following sedation using two intramuscular (IM) sedation protocols in cats: hydromorphone, alfaxalone and midazolam vs hydromorphone and alfaxalone. Methods This was a prospective, randomized and blinded study. Cats were randomly assigned to receive an IM injection of hydromorphone (0.1 mg/kg), alfaxalone (1.5 mg/kg) and midazolam (0.2 mg/kg; HAM group), or hydromorphone (0.1 mg/kg) and alfaxalone (1.5 mg/kg; HA group). Sedation scoring (0–9, where 9 indicated maximum sedation) was performed at 0, 5, 10, 15 and 20 mins from the time of injection. At 20 mins, an IV catheter placement score (0–10, where 10 indicated least resistance) was performed. Results Twenty-one client-owned adult cats were included in this study. Sedation and IV catheter placement scores were compared between groups using Wilcoxon rank sum tests. Peak sedation was significantly higher ( P = 0.002) in the HAM group (median 9; range 7–9) than in the HA group (median 7; range 3–9), and IV catheter placement scores were significantly higher ( P = 0.001) in the HAM group (median 9.5; range 7–10) compared with the HA group (median 7; range 4–9). Spearman correlations were calculated between IV catheter placement score and sedation scores. There was a significant positive correlation of average sedation over time (correlation 0.83; P Conclusions and relevance These preliminary results suggest that the addition of midazolam to IM alfaxalone and hydromorphone produced more profound sedation and greater ease of IV catheter placement than IM alfaxalone and hydromorphone alone.

Longitudinal changes in aortic diameters of young patients with thoracic aortic aneurysm (TAA) have not been completely described, particularly over long periods of follow-up. This retrospective study sought to characterize the rates of proximal aortic dilation in young patients, identify risk factors for TAA progression, and evaluate the predictive utility of early echocardiographic follow-up. Inclusion criteria were: (1) TAA or TAA-predisposing genetic diagnosis, (2) age 25 years at first echocardiogram, and (3) minimum of 5 years of echocardiographic follow-up. Proximal aortic diameters were measured by echocardiography and Z-scores calculated to index for body surface area. TAA severity was classified as no TAA (Z-score 2), mild (Z-score 2 to 4), or at least moderate (Z-score 4). Among 141 included patients, mean age at first echocardiogram was 7.3 ± 3.5 years. Mean follow-up duration was 9.8 ± 3.5 years. Fifty five patients had a genetic syndrome, and 38 of the non-syndromic patients had bicuspid aortic valve (BAV). The rate of aortic dilation was significantly higher at the ascending aorta than other aortic segments. BAV and age 10 years at first echocardiogram were associated with increased rate of ascending aorta dilation. At the ascending aorta, over 25% of patients had categorical increase in TAA severity between first and last echocardiograms, and such patients demonstrated higher rate of dilation within their first 2 years of follow-up. These longitudinal findings highlight progressive ascending aorta dilation in young patients, which may worsen around adolescence. This may help determine timing of follow-up and target ages for clinical trials.

Despite nation-wide decreases in crime, urban gun violence remains a serious and pressing issue in many cities. Victim survival in these incidents is often contingent on the speed and quality of care provided. Increasingly, new research has identified the role that specialized trauma care plays in victim survival from firearm-related injuries. Using nearly four years of data on shooting victimizations in Philadelphia we test whether distance to the nearest level 1 trauma center is associated with victim survival. We employ different distance measures based on straight-line Euclidian distance, street network distances, and drive-time estimates—comparing the predictive accuracy of each. Our results find that victims who are shot farther from trauma centers have an increased likelihood of death, and drive time distances provide the most accurate predictions. We discuss the practical implications of this research as it applies to urban public health.

Increased awareness of von Willebrand Disease (VWD) has led to more frequent diagnostic laboratory testing, which insurers often dictate be performed at a facility with off-site laboratory processing, instead of a coagulation facility with onsite processing. Off-site processing is more prone to preanalytical variables causing falsely low levels of von Willebrand Factor (VWF) due to the additional transport required. Our aim was to determine the percentage of discordance between off-site and onsite specimen processing for VWD in this multicenter, retrospective study. We enrolled females aged 12 to 50 years who had off-site specimen processing for VWF assays, and repeat testing performed at a consulting institution with onsite coagulation phlebotomy and processing. A total of 263 females from 17 institutions were included in the analysis. There were 251 subjects with both off-site and onsite VWF antigen (VWF:Ag) processing with 96 (38IU/dL) being low off-site and 56 (22IU/dL) low onsite; 223 subjects had VWF ristocetin co-factor (VWF:RCo), 122 (55IU/dL) were low off-site and 71 (32IU/dL) were low onsite. Similarly, 229 subjects had a Factor VIII (FVIII) assay, and 67 (29IU/dL) were low off-site with less than half, 29 (13IU/dL) confirmed low with onsite processing. Higher proportions of patients demonstrated low VWF:Ag, VWF:RCo, and/or FVIII with off-site processing compared to onsite (McNemar's test P-value

OBJECTIVEMultiple endocrine neoplasia type 1 (MEN1) is a rare, autosomal-dominant tumor disorder characterized by the development of pituitary tumors and other endocrine neoplasms. Diagnosis is made clinically based on the development of 2 or more canonical lesions (parathyroid gland, anterior pituitary, and enteropancreatic tumors) or in family members of a patient with a clinical diagnosis of MEN1 and the occurrence of one of the MEN1-associated tumors. The goal of this study was to characterize pituitary tumors arising in the setting of MEN1 at a single institution. The probability of tumor progression and the likelihood of surgical intervention in patients with asymptomatic nonfunctional pituitary adenomas were also analyzed.METHODSA retrospective review of a prospectively maintained institutional database was performed for patients with MEN1 diagnosed from 1970 to 2017. Data included patient demographics, tumor characteristics, treatment strategies, and outcomes.RESULTSA review of the database identified 268 patients diagnosed with MEN1, of whom 158 (59%) were female. Among the 268 patients, 139 (51.8%) had pituitary adenomas. There was a higher prevalence in women than in men (65% vs 35%, p < 0.005). Functional adenomas (57%) were more common. Prolactin-secreting adenomas were the most common functional tumors. Macroadenomas were seen in 27% of patients and were more likely to be symptomatic and locally aggressive (p < 0.001). Forty-nine patients (35%) underwent transsphenoidal resection at some point during their disease course. In 52 patients who were initially observed with MEN1 asymptomatic nonfunctional adenomas, only 5 (10%) progressed to need surgery. In MEN1 patients, an initial parathyroid lesion is most likely followed in order by pituitary, pancreatic, adrenal, and, finally, rare carcinoid tumors.CONCLUSIONSAsymptomatic nonfunctional pituitary adenomas in patients with MEN1 may be followed safely with MRI. In this series, parathyroid tumors developed at the lowest median age of all cardinal tumors, and development of additional cardinal MEN1 lesions followed a predictable pattern. This pattern of disease progression could have significant implications for disease surveillance in clinical practice and may help to target clinical resources to the lesions most likely to develop next. This may aid with early detection and treatment and warrants further study.

BackgroundThrombosis with thrombocytopenia syndrome (TTS) is a potentially life-threatening condition associated with adenoviral-vectored COVID-19 vaccination. TTS presents similarly to autoimmune heparin-induced thrombocytopenia. Twelve cases of cerebral venous sinus thrombosis following Janssen/Johnson & Johnson (Ad26.COV2.S) COVID-19 vaccination have been described.ObjectiveDescribe surveillance data and reporting rates of TTS cases following COVID-19 vaccination.DesignCase series.SettingUnited StatesPatientsCase-patients reported to the Vaccine Adverse Event Reporting System (VAERS) receiving COVID-19 vaccine from December 14, 2020 through August 31, 2021, with thrombocytopenia and thrombosis (excluding isolated ischemic stroke or myocardial infarction). If thrombosis was only in an extremity vein or pulmonary embolism, a positive enzyme-linked immunosorbent assay for anti-platelet factor 4 antibody was required.MeasurementsReporting rates (cases/million vaccine doses) and descriptive epidemiology.Results52 TTS cases were confirmed following Ad26.COV2.S (n=50) or mRNA-based COVID-19 (n=2) vaccination. TTS reporting rates were 3.55 per million (Ad26.COV2.S) and 0.0057 per million (mRNA-based COVID-19 vaccines). Median age of patients with TTS following Ad26.COV2.S vaccination was 43.5 years (range: 18–70); 70% were female. Both TTS cases following mRNA-based COVID-19 vaccination occurred in males aged >50 years. All cases following Ad26.COV2.S vaccination involved hospitalization including 32 (64%) with intensive care unit admission. Outcomes of hospitalizations following Ad26.COV2.S vaccination included death (12%), discharge to post-acute care (16%), and discharge home (72%).LimitationsUnder-reporting and incomplete case follow-up.ConclusionTTS is a rare but serious adverse event associated with Ad26.COV2.S vaccination. The different demographic characteristics of the two cases reported after mRNA-based COVID-19 vaccines and the much lower reporting rate suggest that these cases represent a background rate.Funding SourceCDC

Black gay, bisexual, and other Black sexual minority men (BSMM) continue to experience some of the largest sexual health disparities in the U.S. Engaging BSMM in PrEP is crucial to improving sexual health outcomes and reducing disparities. However, knowledge of the profiles of sexual risk and PrEP initiation among this group is limited.This study used latent class analysis to identify HIV risk and PrEP initiation patterns among BSMM in the HPTN 073 Study (n = 226). Guided by current Centers for Disease Control screening guidelines, latent class indicators included relationship status, condom use, number of sexual partners, substance use, sexually transmitted infection (STI) history, and partner HIV status. Age and PrEP initiation were used in a multinomial regression to identify correlates of class membership. Three latent classes were identified: Single, Condomless Partners, Single, Multiple Partners, and Serodiscordant Partners. Single, Condomless Partners had the highest conditional probabilities of having greater than three male partners, substance use before sex, and receiving an STI diagnosis. Serodiscordant Partners had a 100% conditional probability of condomless sex and having a male partner living with HIV. BSMM who initiated PrEP were less likely to be classified as Single, Condomless Partners than Serodiscordant Partners (AOR = 0.07, 95% CI = 0.02, 0.66). Findings support the need forculturally relevanttailored and targeted messaging for BSMM with multiple sexual risk indicators.

Background Clinical application of population pharmacokinetics (popPK) is of increasing interest to patients with hemophilia, providers, and payers. Routine use of popPK profiles in factor replacement prophylaxis decision making has the potential to maintain or improve efficacy and reduce product consumption. Aim To investigate the feasibility of implementation and longitudinal assessment of pharmacokinetic (PK)‐tailored prophylaxis in routine clinical practice for hemophilia A and to describe factors that influence decision making for prescribed hemophilia prophylaxis. Methods This longitudinal, multicenter, prospective feasibility study of children and adults with hemophilia A without inhibitors used the Web Accessible Population Pharmacokinetic Service—Hemophilia (WAPPS‐Hemo) to generate PK profiles. Assessments over 12 weeks captured data on prescribed prophylaxis, popPK tool use, provider decision making, and patient‐reported outcomes. Results Eighteen participants aged 6 to 39 years enrolled; half used extended half‐life concentrates. Patient interest in their PK centered on general curiosity followed by a desire for participation in physical activity and decrease in infusion frequency. Providers used the WAPPS clinical calculator feature to simulate prophylaxis regimens under different dose, infusion, and trough conditions. Most targeted troughs were 1 to 3 IU/dL. The feasibility assessment demonstrated challenges with patient recruitment; however, the majority of participants successfully completed study assessments meeting feasibility targets. Conclusion A larger‐scale study powered to evaluate the impact of PK‐tailored prophylaxis on clinical and patient‐reported outcomes is feasible with study design modifications to support increased recruitment rate. Shared decision making incorporating patient and provider goals is important and facilitated by regimen simulations with the clinical calculator.

Background N8‐GP is an extended half‐life recombinant factor VIII developed for prophylaxis and treatment of bleeds in patients with hemophilia A. Objective To assess pharmacokinetic (PK) characteristics of N8‐GP in previously treated patients with severe hemophilia A, model the time spent at hemophilia thresholds of ≥1 and ≤5 IU/dL (moderate) or >5 IU/dL (mild) FVIII levels during N8‐GP prophylaxis, and investigate the relationship between N8‐GP half‐life and von Willebrand factor (vWF). Methods PK assessments were obtained from patients with severe hemophilia A (FVIII < 1 IU/dL) participating in 4 clinical trials: pathfinder 1 (20‐60 years); pathfinder 2 (12‐17 and ≥18 years); pathfinder 5 (0‐11 years), and pathfinder 7 (25‐71 years). All PK profiles were assessed after washout and considered single‐dose PK profiles. Pre‐ and postdose FVIII activity at steady state was measured at all visits. Results From 69 patients, 108 PK profiles of N8‐GP 50 IU/kg were assessed. Adults/adolescents received 50 IU/kg every 4 days, achieving mean trough levels of 3.0 IU/dL (95% confidence interval, 2.6‐3.5, adults) and 2.7 IU/dL (1.8‐4.0, adolescents). Children received 60 IU/kg twice weekly, leading to mean trough levels of 1.2 IU/dL (0.8‐1.6, 0‐ to 5‐year‐olds) and 2.0 IU/dL (1.5‐2.7, 6‐ to 11‐year‐olds). PK modeling predicted children dosed every 3 days and adults/adolescents dosed every 3 to 4 days would maintain FVIII levels >5 and >1 IU/dL for >80% and 100% of the time, respectively. N8‐GP half‐life correlated linearly with von Willebrand factor levels in adults/adolescents, less in children. Conclusions Prophylaxis with fixed intervals (Q4D/twice weekly) and fixed weight‐based dosing (50/60 IU/kg) ensured >1 IU/dL FVIII trough levels in both adults and children.

The legalization of medical marijuana remains a controversial policy. An important dimension of marijuana legalization is the siting of dispensaries and their influence on a surrounding community. ...

Interactions between cells and the extracellular matrix, mediated by integrin adhesion complexes (IACs), play key roles in cancer progression and metastasis. We investigated systems-level changes in the integrin adhesome during metastatic progression of a patient-derived cutaneous squamous cell carcinoma (cSCC), and found that the actin regulatory protein Mena is enriched in IACs in metastatic cSCC cells. Mena is connected within a subnetwork of actin-binding proteins to the LINC complex component nesprin-2, with which it interacts and co-localises at the nuclear envelope of metastatic cells. Moreover, Mena potentiates the interactions of nesprin-2 with the actin cytoskeleton and the nuclear lamina. CRISPR-mediated Mena depletion causes altered nuclear morphology, reduces tyrosine phosphorylation of the nuclear membrane protein emerin and downregulates expression of the immunomodulatory gene PTX3 via the recruitment of its enhancer to the nuclear periphery. We have uncovered an unexpected novel role for Mena at the nuclear membrane, where it controls the LINC complex, nuclear architecture, chromatin repositioning and cancer gene expression. This is the first description of an adhesion protein regulating gene transcription via direct signalling across the nuclear envelope.Abstract Figure

BACKGROUND: Hospital-associated venous thromboembolism (HA-VTE) is an increasing cause of morbidity in pediatric populations, yet identification of high-risk patients remains challenging. General pediatric models have been derived from case-control studies, but few have been validated. We developed and validated a predictive model for pediatric HA-VTE using a large, retrospective cohort. METHODS: The derivation cohort included 111 352 admissions to Monroe Carell Jr. Children’s Hospital at Vanderbilt. Potential variables were identified a priori, and corresponding data were extracted. Logistic regression was used to estimate the association of potential risk factors with development of HA-VTE. Variable inclusion in the model was based on univariate analysis, availability in routine medical records, and clinician expertise. The model was validated by using a separate cohort with 44 138 admissions. RESULTS: A total of 815 encounters were identified with HA-VTE in the derivation cohort. Variables strongly associated with HA-VTE include history of thrombosis (odds ratio [OR] 8.7; 95% confidence interval [CI] 6.6–11.3; P < .01), presence of a central line (OR 4.9; 95% CI 4.0–5.8; P < .01), and patients with cardiology conditions (OR 4.0; 95% CI 3.3–4.8; P < .01). Eleven variables were included, which yielded excellent discriminatory ability in both the derivation cohort (concordance statistic = 0.908) and the validation cohort (concordance statistic = 0.904). CONCLUSIONS: We created and validated a risk-prediction model that identifies pediatric patients at risk for HA-VTE development. We anticipate early identification of high-risk patients will increase prophylactic interventions and decrease the incidence of pediatric HA-VTE.

Importance Cerebral venous sinus thrombosis (CVST) with thrombocytopenia, a rare and serious condition, has been described in Europe following receipt of the ChAdOx1 nCoV-19 vaccine (Oxford/AstraZeneca), which uses a chimpanzee adenoviral vector. A mechanism similar to autoimmune heparin-induced thrombocytopenia (HIT) has been proposed. In the US, the Ad26.COV2.S COVID-19 vaccine (Janssen/Johnson & Johnson), which uses a human adenoviral vector, received Emergency Use Authorization (EUA) on February 27, 2021. By April 12, 2021, approximately 7 million Ad26.COV2.S vaccine doses had been given in the US, and 6 cases of CVST with thrombocytopenia had been identified among the recipients, resulting in a temporary national pause in vaccination with this product on April 13, 2021. Objective To describe reports of CVST with thrombocytopenia following Ad26.COV2.S vaccine receipt. Design, Setting, and Participants Case series of 12 US patients with CVST and thrombocytopenia following use of Ad26.COV2.S vaccine under EUA reported to the Vaccine Adverse Event Reporting System (VAERS) from March 2 to April 21, 2021 (with follow-up reported through April 21, 2021). Exposures Receipt of Ad26.COV2.S vaccine. Main Outcomes and Measures Clinical course, imaging, laboratory tests, and outcomes after CVST diagnosis obtained from VAERS reports, medical record review, and discussion with clinicians. Results Patients’ ages ranged from 18 to younger than 60 years; all were White women, reported from 11 states. Seven patients had at least 1 CVST risk factor, including obesity (n = 6), hypothyroidism (n = 1), and oral contraceptive use (n = 1); none had documented prior heparin exposure. Time from Ad26.COV2.S vaccination to symptom onset ranged from 6 to 15 days. Eleven patients initially presented with headache; 1 patient initially presented with back pain and later developed headache. Of the 12 patients with CVST, 7 also had intracerebral hemorrhage; 8 had non-CVST thromboses. After diagnosis of CVST, 6 patients initially received heparin treatment. Platelet nadir ranged from 9 ×103/µL to 127 ×103/µL. All 11 patients tested for the heparin-platelet factor 4 HIT antibody by enzyme-linked immunosorbent assay (ELISA) screening had positive results. All patients were hospitalized (10 in an intensive care unit [ICU]). As of April 21, 2021, outcomes were death (n = 3), continued ICU care (n = 3), continued non-ICU hospitalization (n = 2), and discharged home (n = 4). Conclusions and Relevance The initial 12 US cases of CVST with thrombocytopenia after Ad26.COV2.S vaccination represent serious events. This case series may inform clinical guidance as Ad26.COV2.S vaccination resumes in the US as well as investigations into the potential relationship between Ad26.COV2.S vaccine and CVST with thrombocytopenia.

Current therapeutic options for treating colorectal cancer have little clinical efficacy and acquired resistance during treatment is common, even following patient stratification. Understanding the mechanisms that promote therapy resistance may lead to the development of novel therapeutic options that complement existing treatments and improve patient outcome. Here, we identify RAC1B as an important mediator of colorectal tumourigenesis and a potential target for enhancing the efficacy of EGFR inhibitor treatment. We find that high RAC1B expression in human colorectal cancer is associated with aggressive disease and poor prognosis and deletion of Rac1b in a mouse colorectal cancer model reduces tumourigenesis. We demonstrate that RAC1B interacts with, and is required for efficient activation of the EGFR signalling pathway. Moreover, RAC1B inhibition sensitises cetuximab resistant human tumour organoids to the effects of EGFR inhibition, outlining a potential therapeutic target for improving the clinical efficacy of EGFR inhibitors in colorectal cancer., RAC1 is a downstream target of the Wnt signaling that promotes intestinal stem cell expansion and tumorigenesis. Here, the authors identify the specific splice variant RAC1B as an important mediator of colorectal tumourigenesis and a potential target for enhancing the efficacy of EGFR inhibitor treatment.

Early implantable epilepsy therapy devices provided open-loop electrical stimulation without brain sensing, computing, or an interface for synchronized behavioral inputs from patients. Recent epilepsy stimulation devices provide brain sensing but have not yet developed analytics for accurately tracking and quantifying behavior and seizures. Here we describe a distributed brain co-processor providing an intuitive bi-directional interface between patient, implanted neural stimulation and sensing device, and local and distributed computing resources. Automated analysis of continuous streaming electrophysiology is synchronized with patient reports using a hand-held device and integrated with distributed cloud computing resources for quantifying seizures, interictal epileptiform spikes, and patient symptoms during therapeutic electrical brain stimulation. The classification algorithms for interictal epileptiform spikes and seizures were developed and parameterized using long-term ambulatory data from 9 humans and 8 canines with epilepsy, and then implemented prospectively in out-of-sample testing in 2 pet canines and 4 humans with drug resistant epilepsy living in their natural environments.

Background Convalescent plasma is being used widely as a treatment for coronavirus disease 2019 (COVID-19). However, the clinical efficacy of COVID-19 convalescent plasma is unclear. Methods The Passive Immunity Trial for Our Nation (PassITON) is a multicenter, placebo-controlled, blinded, randomized clinical trial being conducted in the USA to provide high-quality evidence on the efficacy of COVID-19 convalescent plasma as a treatment for adults hospitalized with symptomatic disease. Adults hospitalized with COVID-19 with respiratory symptoms for less than 14 days are eligible. Enrolled patients are randomized in a 1:1 ratio to 1 unit (200–399 mL) of COVID-19 convalescent plasma that has demonstrated neutralizing function using a SARS-CoV-2 chimeric virus neutralization assay. Study treatments are administered in a blinded fashion and patients are followed for 28 days. The primary outcome is clinical status 14 days after study treatment as measured on a 7-category ordinal scale assessing mortality, respiratory support, and return to normal activities of daily living. Key secondary outcomes include mortality and oxygen-free days. The trial is projected to enroll 1000 patients and is designed to detect an odds ratio ≤ 0.73 for the primary outcome. Discussion This trial will provide the most robust data available to date on the efficacy of COVID-19 convalescent plasma for the treatment of adults hospitalized with acute moderate to severe COVID-19. These data will be useful to guide the treatment of COVID-19 patients in the current pandemic and for informing decisions about whether developing a standardized infrastructure for collecting and disseminating convalescent plasma to prepare for future viral pandemics is indicated. Trial registration ClinicalTrials.gov NCT04362176. Registered on 24 April 2020.

The COVID-19 pandemic revealed an urgent need for rapid profiling of neutralizing antibody responses and development of antibody therapeutics. The current Food and Drug Administration-approved serological tests do not measure antibody-mediated viral neutralization, and there is a need for standardized quantitative neutralization assays. We report a high-throughput two-step profiling approach for identifying neutralizing convalescent plasma. Screening and down-selection for serum antibody binding to the receptor-binding domain are followed by quantitative neutralization testing using a chimeric vesicular stomatitis virus expressing spike protein of SARS-CoV-2 in a real-time cell analysis assay. This approach enables a predictive screening process for identifying plasma units that neutralize SARS-CoV-2. To calibrate antibody neutralizing activity in serum from convalescent plasma donors, we introduce a neutralizing antibody standard reagent composed of two human antibodies that neutralize SARS-CoV strains, including SARS-CoV-2 variants of concern. Our results provide a framework for establishing a standardized assessment of antibody-based interventions against COVID-19. Funding Information: This work was supported by the National Institute of Health (NIH) National Center for Advancing Translational Sciences (NCATS) grant 3UL1TR002243-04S4, Vanderbilt Institute for Infection, Immunology, and Inflammation (VI4), the Hays Foundation COVID-19 Research Fund (to I.T.), Defense Advanced Research Projects Agency (DARPA) grant HR0011-18-2-0001, U.S. N.I.H. contract 75N93019C00074, the Dolly Parton COVID-19 Research Fund at Vanderbilt, and a grant from Fast Grants, Mercatus Center, George Mason University. Declaration of Interests: I.T. reports grants from NIH/NIAID, during the conduct of the study, and has served as a consultant for Nashville Biosciences and Horizon Therapeutics. J. D. C., L.J.S., and M.R.D. report grants from NIH/NCATS, during the conduct of the study. T.W.R. reports grants from NIH/NCATS, during the conduct of the study; personal fees from Cumberland Pharmaceuticals, Inc, personal fees from Sanofi Pharma, and personal fees from Cytovale, outside the submitted work. T.G.S. reports grants from NIH, during the conduct of the study. W.H.S. reports grants from NCATS of the NIH, during the conduct of the study. M.S.D. is a consultant for Inbios, Vir Biotechnology, Fortress Biotech, and Carnival Corporation and on the Scientific Advisory Boards of Moderna an Immunome. The Diamond laboratory has received funding support in sponsored research agreements from Moderna, Vir Biotechnology and Emergent BioSolutions. J.E.C. has served as a consultant for Luna Biologics, is a member of the Scientific Advisory Board of Meissa Vaccines and is Founder of IDBiologics. The Crowe laboratory at Vanderbilt University Medical Center has received sponsored research agreements from Takeda Vaccines, IDBiologics and AstraZeneca and grants from NIH, and DARPA during the conduct of the study. Vanderbilt University has applied for patents related to antibodies described in this paper. All other authors declare no competing interests. Ethics Approval Statement: The studies were approved by the Vanderbilt University Medical Center Institutional Review Board, and samples were collected after written informed consent was obtained by research personnel.

International audience; Inappropriate stimulation or defective negative regulation of the type I interferon response can lead to autoinflammation. In genetically uncharacterized cases of the type I interferonopathy Aicardi-Goutières syndrome, we identified biallelic mutations in LSM11 and RNU7-1, which encode components of the replication-dependent histone pre-mRNA-processing complex. Mutations were associated with the misprocessing of canonical histone transcripts and a disturbance of linker histone stoichiometry. Additionally, we observed an altered distribution of nuclear cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) and enhanced interferon signaling mediated by the cGAS-stimulator of interferon genes (STING) pathway in patient-derived fibroblasts. Finally, we established that chromatin without linker histone stimulates cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) production in vitro more efficiently. We conclude that nuclear histones, as key constituents of chromatin, are essential in suppressing the immunogenicity of self-DNA.

While HIV infections among men who have sex men (MSM) have started to decline in the United States, Black MSM continue to experience disproportionate rates of HIV infection. The purpose of this secondary analysis is to examine risk perception and its influence on PrEP adherence among Black MSM from HPTN 073. Risk perception was measured using the adapted Perceived Vulnerability to HIV Scale. The associations between risk perception and PrEP adherence were tested using generalized estimation equation model for time-variant repeated measures. Risk perception was not significantly associated with PrEP adherence. These findings suggest an there was no risk compensation among PrEP users, and inconsistency in perceived risk for HIV. Future studies should investigate the rationale for long term adherence to PrEP among Black MSM.

Study Objective Heavy menstrual bleeding (HMB) may be the sentinel event for identifying a patient with a bleeding disorder (BD). The levonorgestrel intrauterine system (LNG IUS) has been proposed as a treatment for HMB in adolescents with and without BDs; however, no standard protocols for LNG IUS insertion in these populations exist. Providers were surveyed regarding the use of the LNG IUS in adolescents with HMB, with and without BD. Design, Setting, Participants, Interventions, and Main Outcome Measures An institutional review board−approved survey assessing provider attitudes, LNG IUS insertion practices, and patient outcomes in adolescents with HMB, with and without BD, was electronically distributed to 3523 providers in the fields of hematology, adolescent medicine, and obstetrics and gynecology. Descriptive analysis was performed. Results A total of 312 respondents across all 3 specialties completed the survey. Nearly 100% of respondents considered the LNG IUS safe and effective treatment for adolescents with HMB, both with and without BD. Additionally, 66% of providers chose LNG IUS as the ideal treatment for HMB in patients with BD. Differences were noted in clinical setting for LNG IUS insertion, peri-procedural medication use, and post-procedure follow-up among specialties. Providers across all specialties reported low complication rates related to IUS insertion and use in both patient groups. Conclusion Providers considered the LNG IUS safe and effective treatment for HMB in adolescents with and without a diagnosed BD. Practice patterns regarding LNG IUS insertion in this population vary. Further research is necessary to explore IUS outcomes in adolescent patients with HMB, with and without BD, and to inform evidence-based protocols for LNG IUS insertion.

Introduction Factor XI (FXI) deficiency is associated with highly variable bleeding, including excessive gynecologic and obstetrical bleeding. Since approximately 20% of FXI-deficient women will experience pregnancy-related bleeding, careful planning and knowledge of appropriate hemostatic management is pivotal for their care. Areas covered In this manuscript, authors present our current understanding of the role of FXI in hemostasis, the nature of the bleeding phenotype caused by its deficiency, and the impact of deficiency on obstetrical care. The authors searched PubMed with the terms, 'factor XI', 'factor XI deficiency', 'women', 'pregnancy', and 'obstetrics' to identify literature on these topics. Expectations of pregnancy-related complications in women with FXI deficiency, including antepartum, abortion-related, and postpartum bleeding, as well as bleeding associated with regional anesthesia are discussed. Recommendations for the care of these women are considered, including guidance for management of prophylactic care and acute bleeding. Expert commentary FXI deficiency results in a bleeding diathesis in some, but not all, patients, making treatment decisions and clinical management challenging. Currently available laboratory assays are not particularly useful for distinguishing patients with FXI deficiency who are prone to bleeding from those who are not. There is a need for alternative testing strategies to address this limitation.

Background The HIV Prevention Trials Network (HPTN) Study 073 (HPTN 073) assessed the feasibility, acceptability, and safety of preexposure prophylaxis (PrEP) for black men who have sex with men (BMSM). The purpose of this analysis was to characterize the relationship between PrEP uptake and use and incident sexually transmitted infections (STIs) among participants enrolled in HPTN 073. Methods A total of 226 human immunodeficiency virus (HIV)–uninfected BMSM were enrolled in 3 US cities; all participants received client-centered care coordination (C4) and were offered daily oral PrEP. Participants were followed for 12 months with STI testing (rectal and urine nucleic acid amplification test for gonorrhea and chlamydia, rapid plasma reagin for syphilis) conducted at baseline, week 26, and week 52. Logistic regression was used to examine associations between STI incidence and PrEP uptake. Generalized estimating equations were used to evaluate associations between age, PrEP acceptance, sexual behaviors, and incident STIs. Results Baseline STI prevalence was 14.2%. Men aged Conclusions While we found higher rates of STIs in younger BMSM, overall rates of STI were lower than in prior PrEP trials, with no increase over time. BMSM with STIs at PrEP initiation may require additional interventions that target STI acquisition risk. Clinical Trials Registration NCT01808352.

Background: Low back pain is responsible for significant personal and societal burden, particularly when it becomes persistent. Despite international consensus regarding the judicious use of diagnostic spinal imaging, patients continue to be over-referred. Objective: The aim of this article is to highlight the critical need for primary care clinicians to engage in thoughtful use of imaging procedures, and to consider alternative or adjunct methods for providing reassurance, in order to avoid or mitigate the potential negative impact of 'anomalous' findings. Discussion: While imaging is frequently requested with the goal of reassuring patients, it can paradoxically have a negative impact on patient attitudes and beliefs and can influence pain behaviours. For improved patient outcomes we recommend contextualisation of radiological findings within age-related norms, use of reassuring and non‑threatening language when communicating results, and educating patients on non‑pathoanatomical contributors to pain. Refereed/Peer-reviewed

Repair of complex CNS circuitry requires newly incorporated neurons to become appropriately, functionally integrated. One approach is to direct differentiation of endogenous progenitors in situ, or ex vivo followed by transplantation. Prior studies find that newly incorporated neurons can establish long-distance axon projections, form synapses and functionally integrate in evolutionarily old hypothalamic energy-balance circuitry. We now demonstrate that postnatal neocortical connectivity can be reconstituted with point-to-point precision, including cellular integration of specific, molecularly identified projection neuron subtypes into correct positions, combined with development of appropriate long-distance projections and synapses. Using optogenetics-based electrophysiology, experiments demonstrate functional afferent and efferent integration of transplanted neurons into transcallosal projection neuron circuitry. Results further indicate that ‘primed’ early postmitotic neurons, including already fate-restricted deep-layer projection neurons and/or plastic postmitotic neuroblasts with partially fate-restricted potential, account for the predominant population of neurons capable of achieving this optimal level of integration. This work demonstrates subtype-specific molecular fidelity, laminar positioning, long-distance interhemisheric connectivity and electrophysiologic circuit integration by developmentally primed, microtransplanted neurons in postnatal mouse neocortex.

Introduction: N8-GP is an extended half-life recombinant factor VIII product indicated for use in patients with hemophilia A. The pathfinder trials evaluated routine prophylaxis and bleed control in previously treated patients aged ≥12 years (pathfinder2) and patients aged Methods: In the pathfinder2 trial, patients aged ≥12 years with severe hemophilia A were administered N8-GP 50 IU/kg every 4 days (Q4D) as routine prophylaxis or 20 to 70 IU/kg as on-demand treatment. Patients aged Results: See Table for efficacy in prophylaxis (median annualized bleeding rates [ABRs]) and bleed treatment (success rate). Median ABRs tended to decrease from 0.84 (global) and 0.86 (US) in pathfinder2 to 0.00 (global) and 0.00 (US) in pathfinder8 in patients aged ≥12 years on the prophylaxis regimen. In addition, in patients aged Overall, there were 59 treatment-related adverse events (AEs) in patients on the prophylactic regimen in pathfinder2, 13 of which occurred in US patients, and 11 treatment-related AEs in patients treated on-demand, 3 of which occurred in US patients. In pathfinder5, there were 16 treatment-related AEs, 7 of which occurred in US patients. In pathfinder8, there were 6 treatment-related AEs in patients aged ≥12 years, 3 of which were in US patients. In addition, there was 1 treatment-related AE in a non-US patient aged 5 Bethesda units. The patient returned to their previous FVIII product, and their inhibitor status was negative at follow-up. Conclusions: Efficacy of N8-GP was sustained during the main and extension pathfinder trials in both global and US patients. In addition, a favorable safety profile was maintained throughout the course of the program. Figure 1 Figure 1. Disclosures Wheeler: Novo Nordisk A/S: Consultancy; Bayer: Consultancy; BioMarin: Consultancy; HEMA Biologics: Consultancy; Spark: Consultancy; Takeda: Consultancy; UniQure: Consultancy. Kearney: Grifols: Research Funding; Daiichi Sankyo: Research Funding; CVS Pharmacy: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novo Nordisk Inc: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bioverativ/Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Staber: Bayer, CSL Behring, Sanofi, Takeda: Membership on an entity's Board of Directors or advisory committees. Wufsus: Novo Nordisk Inc: Current Employment. Ostrow: Novo Nordisk Inc: Current Employment. Lentz: Novo Nordisk Inc: Consultancy, Honoraria, Research Funding.

Background. Platelet transfusion is a critical therapy for hematology-oncology patients at risk of transfusion-transmitted infection (TTI) and pulmonary injury. Amotosalen-UVA pathogen reduction (PR) treatment of apheresis platelet components (PC) in plasma or additive solution (INTERCEPT Blood System for Platelets, Cerus, Concord, CA) is FDA approved to reduce risk of TTI and transfusion associated graft vs. host disease (TA-GVHD). PRPC meet the FDA bacteria risk reduction guidance, and approximately 50% of U.S. PC are PRPC. Amotosalen-UVA PR replaces bacteria screening, gamma irradiation, and CMV serology. PR is performed within 24 hours of collection enabling early release of PRPC with 5-day storage. We tested the hypothesis that PRPC were not inferior to conventional PC(CPC) for the incidence of pulmonary injury. Methods. An open-label sequential cohort study in platelet transfusion dependent hematology-oncology patients was conducted under routine practice conditions in 15 clinical centers. Each site enrolled a CPC cohort followed by a PRPC cohort using 4 primary therapy strata matched ± 10%: chemotherapy without hematopoietic cell transplant (HCT), HCT with myeloablation, HCT with non-myeloablative conditioning, and HCT with reduced intensity conditioning (RIC). Patients were supported with the assigned PC type for up to 21 days with 7 days of surveillance after the last PC exposure. Patients participated in only one cohort. The primary endpoint was treatment emergent assisted mechanical ventilation (TEAMV) by intubation or tight mask with positive end expiration pressure (5cm H 2O) after initiation of study PC. All endpoint patients were adjudicated by a blinded pulmonary expert panel (PEP) for diagnosis of acute respiratory distress syndrome (ARDS) by the Berlin Criteria. Secondary endpoints included: time to initiation of TEAMV, clinically significant pulmonary adverse events (CSPAE, CTCAE ≥ Grade 2), transfusion reactions, and mortality. The incidence of TEAMV by non-inferiority (margin = 2.3%), and secondary endpoints were analyzed by modified intention to treat (mITT) and per protocol (PP). Sensitivity analyses with propensity score matching for key variables were conducted for the primary endpoint. The associations between PC and categorical variables were tested by stratified Cochran-Mantel-Haenszel and continuous variables by ANOVA for two-sided significance p = 0.05. results. A total of 2291 pediatric and adult patients (1068 PRPC and 1223 CPC) were enrolled in the respective cohorts with transfusion of 5,277 PRPC and 5,491 CPC. PC assignment compliance and study completion were > 94%. For the mITT data set, the cumulative incidence of TEAMV was lower for the PRPC cohort (log rank p = 0.039) than the CPC cohort (2.9% versus 4.6%, HR = 0.633: 95% CI 0.408-0.982). PRPC by mITT were non-inferior to CPC for the incidence of TEAMV due to all indications, and for TEAMV with pulmonary dysfunction (PD) by PEP (Table). PP analyses were consistent with mITT. Relative risk (RR) of TEAMV showed significantly (p Figure 1 Figure 1. Disclosures Wheeler: Novo Nordisk A/S: Consultancy; Bayer: Consultancy; BioMarin: Consultancy; HEMA Biologics: Consultancy; Spark: Consultancy; Takeda: Consultancy; UniQure: Consultancy. Nooka: Janssen Oncology: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Sanofi: Consultancy; Oncopeptides: Consultancy; Amgen: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy; Adaptive technologies: Consultancy; GlaxoSmithKline: Consultancy, Other: Travel expenses; Karyopharm Therapeutics: Consultancy. Uhl: UpToDate: Patents & Royalties; Abbott: Consultancy, Speakers Bureau; Grifols: Consultancy, Speakers Bureau. Spinella: Secure Transfusion Services: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Cerus Corporation: Consultancy, Research Funding. Liu: Cerus Corporation: Current Employment, Current equity holder in publicly-traded company. Benjamin: Cerus Corporation: Current Employment, Current equity holder in publicly-traded company. Corash: Cerus Corporation: Current Employment, Current equity holder in publicly-traded company.

Resistance to reverse transcriptase and protease inhibitors was frequently detected in HIV from black men who have sex with men (MSM) enrolled in the HIV prevention trials network (HPTN) 061 study. In this study, integrase strand transfer inhibitor (INSTI) resistance was analyzed in black MSM enrolled in HPTN 061 (134 infected at enrollment and 23 seroconverters) and a follow-up study, HPTN 073 (eight seroconverters). The ViroSeq HIV-1 Integrase Genotyping Kit (Abbott Molecular) was used for analysis. Major INSTI resistance mutations were not detected in any of the samples. HIV from 14 (8.4%) of the 165 men, including 4 (12.9%) of 31 seroconverters, had accessory or polymorphic INSTI-associated mutations. The most frequently detected mutation was E157Q. These findings are promising because INSTI-based regimens are now recommended for first-line antiretroviral treatment and because long-acting cabotegravir is being evaluated for pre-exposure prophylaxis.

Black men who have sex with men (BMSM) are a population at the intersection of two minority statuses—racial minority and sexual minority. Membership in either group, compared to white or heterosexual group membership, may increase one’s risk of negative childhood and adult experiences. Baseline data from an HIV intervention efficacy trial (the Black Men Evolving Study) were used to explore the prevalence of adverse childhood experiences (ACEs) among 536 BMSM and associations between ACEs and adult mental and physical health outcomes. Overall, the prevalence of ACEs was high among this sample of BMSM with almost 90% experiencing at least one ACE. Findings revealed that ACE score was significantly associated with adult mental health (AOR = 1.21, 95% CI [1.12, 1.30]), but not with adult physical health. All ACEs were significantly associated with mental health, but only physical neglect and household substance abuse were significantly associated with physical health (AOR = 1.69, 95% CI [1.02, 2.74] and AOR = 1.57, 95% CI [1.03, 2.40], respectively). The findings support the need for interventions targeting improved adult health outcomes, particularly for minority groups, to consider the impact of early adversity on health and wellness.

Introduction: Low von Willebrand factor (VWF) activity is prevalent in adolescents with heavy menstrual bleeding (HMB). There is a need to better genetically characterize these patients and improve our understanding of the pathophysiology of their bleeding risk. Methods: One of the main objectives of this multi-center, single arm, observational cohort study was to genotype adolescent females with HMB and low VWF (≥ 30 and ≤ 50 IU/dL) by means of whole exome sequencing (WES), to identify variants throughout the exome that may modulate risk for bleeding. Post-menarchal females < 21 years with HMB (defined as PBAC score >100) and low VWF were eligible for the study. All patients were enrolled by participating centers where blood samples were collected. Exome data for 86 cases and 900 unrelated pediatric (0.8, GQ>20, AB between 0.3-0.7 and min DP>8. Case/control analyses included common and rare SNP associations, gene burden analysis of both rare nonsynonymous variants and ClinVar 'pathogenic' variants, and gene-set burden analyses. Variants were considered rare if they had a minor allele frequency of Results: Of the 113 subjects enrolled, 86 had sufficient blood samples collected for WES. The median age was 16.2 years (range: 11.5-19.6). 36% of cases showed variants in VWF vs. 26% of controls (p=0.14). After multiple test correction, WES revealed a significant common variant association in FERMT2 with an LD block with a frequency of 24% in cases and 6% in controls (p=7.5x10-7). Rare variant analysis showed a significant association with an intronic variant in ABCA13 (p=1.6x10-7). Among the gene burden analysis using rare nonsynonymous variants, 2 genes of interest passed multiple test correction: IL12B and DTNBP1. When using ClinVar 'pathogenic' variants as the input for the gene burden analysis, 4 genes of interest passed multiple test correction: HBM, MYLK, RUNX1 and CD36. Gene-set burden analysis revealed 5 significant pathways of interest, including platelet degranulation, platelet alpha granule lumen and erythrocyte differentiation. We then focused a subset of known risk genes and compared the number of missense, nonsense and ClinVar 'pathogenic' variants between cases and controls. GP6, and MTHFR had significantly more missense variants in controls vs. cases (p=0.003 and 0.01, respectively), and F13B approached significance, with more missense variants in controls than cases (p=0.07). Conclusion: We found VWF variants in 36% of subjects, in accordance with previous reports. We found novel SNP associations with variants in FERMT2 and ABCA13.FERMT2 encodes for the integrin, Kindlin 2, which has been shown to be critical for supporting vascular integrity. Several other relevant genes passed multiple test correction in gene burden analyses, including genes known to cause Hermansky-Pudlak syndrome (DTNBP1), familial platelet disorder (RUNX1), platelet glycoprotein IV deficiency (CD36) and aortic aneurysm (MYLK). This association with platelet disorders was strengthened by our gene-set burden results, which implicate several platelet-related pathways. These data suggest that while a subset of HMB patients may have their bleeding explained by variants in VWF, there is a role for other hemostasis, platelet biology and vascular integrity related gene variants which can contribute to the variation in bleeding severity in adolescents with low-VWF related HMB. Study supported by an investigator-initiated research grant from Shire US Inc., now part of Takeda Disclosures O'Brien: Bristol Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees. Mullins:Takeda, Bayer: Other: Advisory Board. Sidonio:Takeda: Research Funding. Ragni:Sangamo: Consultancy, Research Funding; Takeda: Research Funding; Bioverativ: Consultancy, Research Funding; Spark: Consultancy, Research Funding; BioMarin: Consultancy, Research Funding; Alnylam/Sanofi, ATHN, BioMarin, Bioverativ, Sangamo, Spark: Research Funding; Alnylam/Sanofi, BioMarin, Bioverativ, Spark: Consultancy; Alnylam Pharmaceuticals Inc., Baxalta/Takeda, BioMarin, Bioverativ, and Spark Therapeutics: Membership on an entity's Board of Directors or advisory committees; American Thrombosis Hemostasis Network: Other: Committee work; Baxalta/Takeda, CSL Behring, Genentech, a member of the Roche Group, OPKO Biologics, and Vascular Medicine Institute: Research Funding. Kulkarni:Sanofi/ Bioverativ, Bayer, Biomarin, Shire/Takeda, Novo Nordisk, Freeline: Other: clinical trial research grants ; Bioverativ/Sanofi, BPL, Genentech, Kedrion, Novo Nordisk, Octapharma, Pfizer, Takeda, Catalyst Bioscience Bayer: Membership on an entity's Board of Directors or advisory committees. Srivaths:Shire US Inc., now part of Takeda: Research Funding.

Introduction: Among the most challenging complications of hemophilia A is inhibitor formation. A T-cell dependent B-cell response to exogenous factor VIII (FVIII), inhibitors result in a high burden of disease, with poorly controlled bleeding, twice the hospitalizations, 10-fold the cost, and 3.5-fold the mortality of non-inhibitor patients. Thus, a major goal of hemophilia management is to prevent and eradicate inhibitors. With the availability of novel therapies, including eloctate, a recombinant Fc-fusion protein (rFVIII-Fc) which induces regulatory T cells to promote FVIII tolerance, and emicizumab, a bispecific monoclonal FVIII mimetic, we designed the INHIBIT Clinical Trials Platform (X01HL143024), Fig.1. The platform is composed of two linked randomized phase III trials, the Inhibitor Prevention Trial (NCT04303559), comparing rFVIII-Fc vs emicizumab prophylaxis to prevent inhibitors, and the Inhibitor Eradication Trial (NCT04303572), comparing rFVIII-Fc immune tolerance induction (ITI) plus emicizumab vs rFVIII-Fc ITI alone to eradicate inhibitors. The platform uses adaptive design to incorporate historical data (Bayesian priors) on inhibitor formation to increase power and promote efficient use of rare data. Yet, there is equipoise regarding the optimal approach to inhibitor prevention and eradication, and, as clinical practice is changing, we aimed to test the feasibility of the INHIBIT trial design. Methods: To establish design feasibility, we conducted interviews with 30 hemophilia treatment center (HTC) physicians participating in the INHIBIT trials, to determine prophylaxis and tolerance regimens they prescribe and perceived barriers to the INHIBIT trials design. A 4-question survey was subsequently emailed to these physicians to ascertain the initial prophylaxis regimens they prescribe in previously untreated patients (PUPs) with severe hemophilia A, and the initial immune tolerance induction (ITI) they prescribe in high-responding inhibitor patients with severe hemophilia A; if new inhibitors had been observed during emicizumab prophylaxis, and willingness to participate in post-trial surveillance. Results: In interviews, HTC physicians indicated the issues that influenced choice of prophylaxis/ ITI regimen were patient preference, family history of inhibitors, infusion frequency, IV access, port requirement, and family fatigue. In the absence of clinical trials data in PUPs, there was general agreement that emicizumab prophylaxis, with it simpler subcutaneous (SQ) administration, might delay or potentially prevent inhibitors. Survey findings in Table 1 indicated 75% of physicians prescribe extended half-life (EHL) FVIII in a once-weekly prophylaxis regimen, as planned in the Prevention Trial, despite the persistent 27% inhibitor rate (ALong PUPs Trial, Königs et al, ISTH 2020) and potential risks with port use. There was support for the 1:3 preferential randomization to emicizumab in the Prevention Trial due to the simpler SQ route, despite concern it might delay rather than prevent inhibitor formation, although no inhibitors were reported by physician survey with emicizumab use alone. There was also concern that breakthrough bleeds requiring FVIII during emicizumab prophylaxis, might lead to immune activation and inhibitor formation. There was strong agreement, however, in 29 (97%) of physicians to participate in post-trial surveillance for long-term inhibitor outcomes. FVIII ITI was considered essential to eradicate inhibitors, despite the intensity of the infusion regimen. Notably, 60% prescribe emicizumab with FVIII ITI, as planned in the Eradicate Trial, although the every-other-day infusion was considered a potential barrier to participation. Omitting FVIII ITI was not favored due to the risk of inhibitor anamnesis if FVIII treatment was subsequently required for surgery or acute hemorrhages. Despite these concerns, there was agreement to participate in the trials. Discussion: Physician interviews and surveys confirm there is heterogeneity in current hemophilia clinical practice, specifically in initial prophylaxis regimens and in initial immune tolerance regimens, including agent choice and duration. However, there is physician consensus with the INHIBIT trial aims and with the proposed INHIBIT trial regimens to prevent and eradicate inhibitors. Disclosures Ragni: Bioverativ: Membership on an entity's Board of Directors or advisory committees, Research Funding; Alnylam/Sanofi: Membership on an entity's Board of Directors or advisory committees, Research Funding; BioMarin: Membership on an entity's Board of Directors or advisory committees, Research Funding; ATHN: Research Funding; Sangamo: Research Funding. Seaman:Bayer: Consultancy; Genentech: Consultancy; Spark Therapeutics: Consultancy; Takeda: Consultancy. Acharya:Novonordisk: Membership on an entity's Board of Directors or advisory committees; BPL: Membership on an entity's Board of Directors or advisory committees; Bayer Pharma Inc.: Research Funding. Wheeler:Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; Biomarin: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; UniQure: Membership on an entity's Board of Directors or advisory committees. Tarango:Takeda/Shire: Honoraria, Other; Bayer: Consultancy, Other; Sanofi: Honoraria, Other. Dunn:ATHN: Research Funding; Spire: Honoraria; Medscape: Honoraria; World Federation of Hemophilia USA: Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding; BioMarin: Research Funding; uniQure: Consultancy; Genentech, Inc.: Consultancy; Nationwide Children's Hospital: Current Employment. Kulkarni:Sanofi/ Bioverativ, Bayer, Biomarin, Shire/Takeda, Novo Nordisk, Freeline: Other: clinical trial research grants ; Bioverativ/Sanofi, BPL, Genentech, Kedrion, Novo Nordisk, Octapharma, Pfizer, Takeda, Catalyst Bioscience Bayer: Membership on an entity's Board of Directors or advisory committees. Ahuja:Genentech: Consultancy, Honoraria; Sanofi Genzyme: Consultancy, Honoraria; XaTek, Inc.: Consultancy, Patents & Royalties, Research Funding. Chitlur:Takeda: Honoraria; Biovertiv: Honoraria; Agios Pharmaceuticals: Research Funding; Pfizer: Honoraria; Novo Nordisk: Consultancy, Honoraria. Pipe:Apcintex, Bayer, BioMarin, Catalyst Biosciences, CSL Behring, HEMA Biologics, Freeline, Novo Nordisk, Pfizer, F. Hoffmann-La Roche Ltd/Genentech, Inc., Sangamo Therapeutics, Sanofi, Takeda, Spark Therapeutics, uniQure: Consultancy; Siemens: Research Funding; Medical and Scientific Advisory Council to the National Hemophilia Foundation; Medical Advisory Board to World Federation of Hemophilia: Membership on an entity's Board of Directors or advisory committees. Malec:Sanofi Genzyme: Consultancy, Research Funding, Speakers Bureau; CSL: Consultancy; Takeda: Consultancy; Bayer: Consultancy; SOBI: Consultancy. Leissinger:Bayer: Consultancy; Kedrion: Consultancy; CSL Behring: Membership on an entity's Board of Directors or advisory committees; Genentech: Consultancy; HEMA Biologics: Consultancy; Takeda: Consultancy; Uniqure: Consultancy; Spark: Consultancy. Carpenter:Hemostasis & Thrombosis Research Society: Membership on an entity's Board of Directors or advisory committees; American Academy of Pediatrics: Other: PREP Heme/Onc editorial board; Kedrion: Honoraria; Novo Nordisk: Honoraria; Genentech, Inc.: Honoraria; American Thrombosis and Hemostasis Network: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Research Funding; Shire: Research Funding. Knoll:NovoNordisk: Membership on an entity's Board of Directors or advisory committees. Wang:Bioverativ Inc: Honoraria; Bayer: Honoraria; CSL Behring: Honoraria; Biomarin: Honoraria; Genentech: Honoraria; Takeda: Honoraria. Young:Genentech/Roche, Grifols, and Takeda: Research Funding; Bayer, CSL Behring, Freeline, UniQure: Consultancy; BioMarin, Freeline, Genentech/Roche, Grifols, Kedrion, Novo Nordisk, Sanofi Genzyme, Spark, Takeda, and UniQure: Honoraria. Thornburg:Genentech: Speakers Bureau; Spark Therapeutics: Consultancy; Bluebird Bio: Consultancy; Ironwood Pharmaceuticals: Consultancy, Other: Data Safety Monitoring Board; American Thrombosis and Hemostasis Network: Research Funding; Sanofi Genzyme: Consultancy, Other: Data Safety Monitoring Board, Research Funding; NovoNordisk: Research Funding; Biomarin: Consultancy, Speakers Bureau; Bayer Pharmaceuticals: Research Funding; National Hemophilia Foundation: Membership on an entity's Board of Directors or advisory committees, Research Funding. Lucas:CRISPR Therapeutics: Membership on an entity's Board of Directors or advisory committees. Hwang:Shire: Honoraria; Takeda: Honoraria.