A pharmacokinetic-pharmacodynamic analysis of l-glutamine for the treatment of sickle cell disease: Implications for understanding the mechanism of action and evaluating response to therapy.

The mechanisms of action of l-glutamine for the treatment of sickle cell disease (SCD) are not well understood and there are no validated clinical biomarkers to assess response. We conducted a three-week, dose-ascending trial of glutamine and measured the pharmacokinetic (PK) exposure parameters, peak concentration (Cmax) and area under the curve (AUC). We used a panel of biomarkers to investigate the pharmacodynamics (PD) of glutamine and studied PK-PD relationships. There was no plasma accumulation of glutamine, glutamate, arginine or other amino acids over time, but modestly improved arginine bioavailability was observed. In standard analysis by dose levels over time, there were no measurable effects on blood counts, viscosity, ektacytometry or reactive oxygen species (ROS). In PK-PD analysis, however, higher glutamine exposure (Cmax or AUC) was associated with increased whole blood viscosity and cellular dehydration, yet also with higher haemoglobin concentration, increased haematocrit-to-viscosity ratio, decreased reticulocyte ROS, improved RBC deformability and decreased point of sickling. This novel PK-PD analysis identified biomarkers reflecting the positive and negative effects of glutamine, helping to elucidate its mechanisms of action in SCD. PK-optimized dosing to achieve glutamine exposure (AUC or Cmax) that is associated with salutary biological effects should be studied to support its therapeutic use.

A Mixed-Methods Evaluation of a Project ECHO Program for the Evidence-Based Management of Sickle Cell Disease.

Sickle cell disease (SCD) is a group of chronic, genetic disorders of the red blood cells with significant gaps in access to evidence-based clinical care. Sickle Treatment and Outcomes Research in the Midwest (STORM), a provider network, utilized Project ECHO (Extension for Community Health Outcomes), a telementoring model, to deliver evidence-based education about SCD management. The purpose of this mixed-methods study is to evaluate the utility of Project ECHO as an educational strategy for healthcare providers treating children and adults with SCD. Annual evaluations were administered to STORM TeleECHO participants from 2016 to 2021. Survey data showed a statistically significant change in self-reported provider confidence in the ability to provide care for adult patients with SCD; identify suitable candidates for disease-modifying therapies; and confidence to prescribe disease-modifying therapies. Participants who attended at least 10 sessions were invited to participate in a semi-structured interview. Qualitative data were analyzed using thematic analysis and several themes emerged about the benefits, including (1) increased confidence, (2) integrated best-practice care, (3) connection to provider network and access to experts, (4) high-quality educational presentations and (5) opportunities for collaboration and a sense of community. This suggests that Project ECHO is accessible and leads to increased confidence in providers caring for individuals with SCD. Overall, participant knowledge gains successfully demonstrated the utility of Project ECHO as an educational resource for providers.

Differing Susceptibilities to Certain Microbicidal Chemistries among Three Representative Enveloped Viruses.

Three lipid-enveloped viruses (bovine viral diarrhea virus [BVDV], vaccinia virus, and severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) were evaluated in side-by-side liquid inactivation efficacy studies of low pH (3.0 to 3.1) treatment and of the non-formulated microbicidal actives sodium hypochlorite (100 ppm), ethanol (70%), quaternary ammonium compound BTC® 835 (100 ppm), and peracetic acid (100 ppm). Low pH was evaluated at 10 and 60 min contact times, and the microbicides were evaluated at 1 min contact time at room temperature per the ASTM E1052 standard. In each case, 5% animal serum was included in the viral inoculum as a challenge soil load. The three viruses displayed similar susceptibility to sodium hypochlorite and ethanol, with complete inactivation resulting. Significant differences in susceptibility to BTC® 835 and peracetic acid were identified, with the ordering of the three viruses for susceptibility to BTC® 835 being SARS-CoV-2 > vaccinia virus = BVDV, and the ordering for peracetic acid being vaccinia virus > SARS-CoV-2 > BVDV. The ordering for susceptibility to low pH treatment (60 min contact time) was vaccinia virus > SARS-CoV-2 > BVDV. Not all enveloped viruses display equivalent susceptibilities to inactivation approaches. For the chemistries evaluated here, BVDV appears to represent a worst-case enveloped virus.

A Population Pharmacokinetic Analysis of L-Glutamine Exposure in Patients with Sickle Cell Disease: Evaluation of Dose and Food Effects.

BACKGROUND AND OBJECTIVE: L-Glutamine is a treatment for children and adults with sickle cell disease. A comprehensive evaluation of the pharmacokinetics of L-glutamine in sickle cell disease has not been conducted. We aimed to assess the effects of long-term dosing, multiple dose levels, and food intake on L-glutamine exposure in patients with sickle cell disease compared to normal participants. METHODS: We conducted an open-label dose-ascending trial of L-glutamine in pediatric and adult participants with sickle cell disease (N = 8) and adult healthy volunteers (N = 4), providing a total of 400 plasma L-glutamine concentrations. Each participant received three ascending oral doses (0.1 and 0.3 g/kg twice daily and 0.6 g/kg once daily) over 3 weeks. Plasma L-glutamine concentrations were quantified using ion exchange chromatography. Both a non-compartmental pharmacokinetic analysis and a population pharmacokinetic analysis were performed. RESULTS: L-glutamine had rapid absorption and elimination, and there was no significant change in the baseline (pre-dose) L-glutamine concentration throughout the study, indicating no drug accumulation. Pharmacokinetics was best described by a one-compartment model with first-order kinetics. The dose-normalized peak concentration decreased with dose escalation, indicating the capacity-limited non-linear pharmacokinetics of oral L-glutamine. A covariate analysis showed that baseline L-glutamine concentrations correlated negatively with glutamine clearance, whereas dose positively correlated with volume of distribution. Food intake did not significantly affect glutamine clearance, indicating that L-glutamine can be taken with or without food. CONCLUSIONS: We report the first pharmacokinetic study of multiple-dose, long-term oral L-glutamine therapy and the first population pharmacokinetic analysis of L-glutamine for sickle cell disease. These findings may permit optimized dosing of L-glutamine for patients with sickle cell disease to maximize treatment benefits. CLINICAL TRIAL REGISTRATION: This trial is registered at ClinicalTrials.gov (NCT04684381).

Nivolumab for Patients With High-Risk Oral Leukoplakia: A Nonrandomized Controlled Trial.

Importance: Proliferative verrucous leukoplakia (PVL) is an aggressive oral precancerous disease characterized by a high risk of transformation to invasive oral squamous cell carcinoma (OSCC), and no therapies have been shown to affect its natural history. A recent study of the PVL immune landscape revealed a cytotoxic T-cell-rich microenvironment, providing strong rationale to investigate immune checkpoint therapy. Objective: To determine the safety and clinical activity of anti-programmed cell death 1 protein (PD-1) therapy to treat high-risk PVL. Design, Setting, and Participants: This nonrandomized, open-label, phase 2 clinical trial was conducted from January 2019 to December 2021 at a single academic medical center; median (range) follow-up was 21.1 (5.4-43.6) months. Participants were a population-based sample of patients with PVL (multifocal, contiguous, or a single lesion ≥4 cm with any degree of dysplasia). Intervention: Patients underwent pretreatment biopsy (1-3 sites) and then received 4 doses of nivolumab (480 mg intravenously) every 28 days, followed by rebiopsy and intraoral photographs at each visit. Main Outcomes and Measures: The primary end point was the change in composite score (size and degree of dysplasia) from before to after treatment (major response [MR]: >80% decrease in score; partial response: 40%-80% decrease). Secondary analyses included immune-related adverse events, cancer-free survival (CFS), PD-1 ligand 1 (PD-L1) expression, 9p21.3 deletion, and other exploratory immunologic and genomic associations of response. Results: A total of 33 patients were enrolled (median [range] age, 63 [32-80] years; 18 [55%] were female), including 8 (24%) with previously resected early-stage OSCC. Twelve patients (36%) (95% CI, 20.4%-54.8%) had a response by composite score (3 MRs [9%]), 4 had progressive disease (>10% composite score increase, or cancer). Nine patients (27%) developed OSCC during the trial, with a 2-year CFS of 73% (95% CI, 53%-86%). Two patients (6%) discontinued because of toxic effects; 7 (21%) experienced grade 3 to 4 immune-related adverse events. PD-L1 combined positive scores were not associated with response or CFS. Of 20 whole-exome sequenced patients, all 6 patients who had progression to OSCC after nivolumab treatment exhibited 9p21.3 somatic copy-number loss on pretreatment biopsy, while only 4 of the 14 patients (29%) who did not develop OSCC had 9p21.3 loss. Conclusions and Relevance: This immune checkpoint therapy precancer nonrandomized clinical trial met its prespecified response end point, suggesting potential clinical activity for nivolumab in high-risk PVL. Findings identified immunogenomic associations to inform future trials in this precancerous disease with unmet medical need that has been difficult to study. Trial Registration: ClinicalTrials.gov Identifier: NCT03692325.

Feasibility of Electronic Medication Monitoring Among Adolescents and Emerging Adults with Sickle Cell Disease.

Purpose: To examine the feasibility of using MEMS® bottles to assess adherence among adolescents and emerging adults with sickle cell disease. Patients and Methods: Eighteen non-Hispanic Black participants with HbSS (M = 17.8 years; 61% male) were given a MEMS® bottle to store hydroxyurea (n = 14) or deferasirox (n = 4). Results: One hundred percent initiated MEMS® use and 61% sustained use through the 18-week study; at follow-up, only 11% returned their bottle on time. Barriers to MEMS® use included medication changes and transition to adult care; facilitators included tip sheets and reminders. Conclusion: While MEMS® is acceptable to this population, ensuring sustained use and timely provision of bottles will require additional supports.

Return visit rates after an emergency department discharge for children with sickle cell pain episodes.

BACKGROUND: High return visit rates after hospitalization for people with sickle cell disease (SCD) have been previously established. Due to a lack of multicenter emergency department (ED) return visit rate data, the return visit rate following ED discharge for pediatric SCD pain treatment is currently unknown. PROCEDURE: A seven-site retrospective cohort study of discharged ED visits for pain by children with SCD was conducted using the Pediatric Emergency Care Applied Research Network Registry. Visits between January 2017 and November 2021 were identified using previously validated criteria. The primary outcome was the 14-day return visit rate, with 3- and 7-day rates also calculated. Modified Poisson regression was used to analyze associations for age, sex, initial hospitalization rate, and a visit during the COVID-19 pandemic with return visit rates. RESULTS: Of 2548 eligible ED visits, approximately 52% were patients less than 12 years old, 50% were female, and over 95% were non-Hispanic Black. The overall 14-day return visit rate was 29.1% (95% confidence interval [CI]: 27.4%-30.9%; site range 22.7%-31.7%); the 7- and 3-day return visit rates were 23.0% (95% CI: 21.3%-24.6%) and 16.7% (95% CI: 15.3%-18.2%), respectively. Younger children had slightly lower 14-day return visit rates (27.3% vs. 31.1%); there were no associations for site hospitalization rate, sex, and a visit occurring during the pandemic with 14-day returns. CONCLUSION: Nearly 30% of ED discharged visits after SCD pain treatment had a return visit within 14 days. Increased efforts are needed to identify causes for high ED return visit rates and ensure optimal ED and post-ED care.

Identification of HPV16 E1 and E2-specific T cells in the oropharyngeal cancer tumor microenvironment.

BACKGROUND: High-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. METHODS: To 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. RESULTS: We 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. CONCLUSIONS: These data highlight antigenicity beyond HPV16 E6 and E7 and nominate candidates for antigen-directed therapies.

Using the consolidated framework for implementation research to identify recruitment barriers and targeted strategies for a shared decision-making randomized clinical trial in pediatric sickle cell disease.

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.

Implementation of CYP2D6-guided opioid therapy at Cincinnati Children's Hospital Medical Center.

PURPOSE: We describe the implementation of CYP2D6-focused pharmacogenetic testing to guide opioid prescribing in a quaternary care, nonprofit pediatric academic medical center. SUMMARY: Children are often prescribed oral opioids after surgeries, for cancer pain, and occasionally for chronic pain. In 2004, Cincinnati Children's Hospital Medical Center implemented pharmacogenetic testing for CYP2D6 metabolism phenotype to inform codeine prescribing. The test and reports were updated to align with changes over time in the testing platform, the interpretation of genotype to phenotype, the electronic health record, and Food and Drug Administration (FDA) guidance. The use of the test increased when a research project required testing and decreased as prescribing of oxycodone increased due to FDA warnings about codeine. Education about the opioid-focused pharmacogenetic test was provided to prescribers (eg, the pain and sickle cell teams) as well as patients and families. Education and electronic health record capability increased provider compliance with genotype-guided postsurgical prescribing of oxycodone, although there was a perceived lack of utility for oxycodone prescribing. CONCLUSION: The implementation of pharmacogenetic testing to inform opioid prescribing for children has evolved with accumulating evidence and guidelines, requiring changes in reporting of results and recommendations.

Iron status and burden of anemia in children with recessive dystrophic epidermolysis bullosa.

BACKGROUND AND OBJECTIVES: 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. METHODS: 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. RESULTS: 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/log10 -ferritin ratio indicated a 1.5-fold higher true prevalence of IDA of 50.6% (41/81). 53.5% (61/114) received parenteral iron infusions, transfusions, or both. Higher ferritin was associated with earlier mortality. CONCLUSIONS: Individuals with RDEB have a high burden of anemia (IDA and anemia of inflammation) that requires frequent medical interventions. The sTfR/log10 -ferritin ratio improves the detection of iron deficiency in the context of inflammation and guides therapy.

Safety and immunogenicity of V114, a 15-valent pneumococcal conjugate vaccine, in children with SCD: a V114-023 (PNEU-SICKLE) study.

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.

Consensus definition of essential, optimal, and suggested components of a pediatric sickle cell disease center.

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.

Early hydroxyurea use is neuroprotective in children with sickle cell anemia.

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.

An Immersive Virtual Reality Curriculum for Pediatric Hematology Clinicians on Shared Decision-making for Hydroxyurea in Sickle Cell Anemia.

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 8 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.