"Treatment with curative intent": the emergence of genetic therapies for sickle cell anemia.

ABSTRACT: The root cause of sickle cell anemia has been known for 7 decades, yet no curative therapies have been available other than allogeneic bone marrow transplantation, for which applicability is limited. Two potentially curative therapies based on gene therapy and gene editing strategies have recently received US Food and Drug Administration approval. This review surveys the nature of these therapies and the opportunities and issues raised by the prospect of definitive genetically based therapies being available in clinical practice.

Risk score to predict event-free survival after hematopoietic cell transplant for sickle cell disease.

We developed a risk score to predict event-free survival (EFS) after allogeneic hematopoietic cell transplantation for sickle cell disease. The study population (n = 1425) was randomly split into training (n = 1070) and validation (n = 355) cohorts. Risk factors were identified and validated via Cox regression models. Two risk factors of 9 evaluated were predictive for EFS: age at transplantation and donor type. On the basis of the training cohort, patients age 12 years or younger with an HLA-matched sibling donor were at the lowest risk with a 3-year EFS of 92% (score, 0). Patients age 13 years or older with an HLA-matched sibling donor or age 12 years or younger with an HLA-matched unrelated donor were at intermediate risk (3-year EFS, 87%; score, 1). All other groups, including patients of any age with a haploidentical relative or HLA-mismatched unrelated donor and patients age 13 years or older with an HLA-matched unrelated donor were high risk (3-year EFS, 57%; score, 2 or 3). These findings were confirmed in the validation cohort. This simple risk score may guide patients with sickle cell disease and hematologists who are considering allogeneic transplantation as a curative treatment relative to other available contemporary treatments.

Detection of changes of functioning over time after asthma exacerbation in children with the use of PROMIS domains.

OBJECTIVES: Patient reported outcome measures, such as the Patient Reported Outcomes Measurement Information System (PROMIS) may be utilized to understand experiences of patients. The purpose of this study was to determine the ability of PROMIS domains to detect changes in pain, physical functioning, and asthma impact over time for children experiencing asthma exacerbation. METHODS: Our prospective cohort study included children presenting to the emergency department (ED) for asthma exacerbation. Children completed PROMIS surveys in the ED, 7-10 days, and 1-3 months post-discharge. We used linear mixed models adjusted for age, gender, acute care utilization, and child global health to determine changes in PROMIS T-scores. We used self-reported child health response (Much better now versus a little better now or worse) at discharge as an anchor to determine if change in PROMIS scores corresponded with changes in health. A change was statistically significant if the 95% CI did not include 0. RESULTS: Our study included 63 children who presented to the ED for acute asthma exacerbation. We identified that children improved significantly in all domains over time. There was improvement over time following discharge from ED for all pain and physical functioning domains, and asthma impact. Using the clinical anchor, those with considerable improvement in asthma symptoms had improved T scores from 4-17. CONCLUSIONS: PROMIS domains of pain, physical functioning, depression, fatigue, peer relationships, and asthma impact are responsive to changes in health states over time. These domains may be used to measure clinically significant change in children experiencing asthma exacerbation.

Development of a conceptual model of patient-reported outcomes in light chain amyloidosis: a qualitative study.

BACKGROUND: Light chain (AL) amyloidosis is a plasma cell neoplasm associated with high early mortality and severe morbidity that can cause severe disability. We explored the impact of AL amyloidosis on symptoms and well-being from the perspectives of patients and health care providers who regularly care for AL patients. We intended to develop a conceptual understanding of patient-reported outcomes in AL amyloidosis to identify the context of use and concept of interest for a clinical outcome assessments tool in this disease. METHOD: Twenty patients and ten professionals were interviewed. Patient interviews captured the spectrum of amyloidosis experience including time from diagnosis, type of organ involvement, and presence and type of treatment received. Interviews with professionals included physicians, advanced practice providers, registered nurse, and a patient advocate; these interviews covered similar topics. RESULTS: The impact of AL amyloidosis on patients' life was multidimensional, with highly subjective perceptions of normality and meaning. Four major themes from patients and experts included diagnosis of AL amyloidosis, living with AL amyloidosis, symptom burden, and social roles. Barriers to patient-reported outcomes data collection in patients were additionally explored from experts. The themes provide a comprehensive understanding of the important experiences of symptom burden and its impact on daily life from AL amyloidosis patients' and from the perspectives of professionals who care for patients with AL amyloidosis. CONCLUSION: These findings further the conceptual understanding and identification of a preliminary model of concept of interest for development of a clinical outcome assessments tool for AL amyloidosis.

Measurement properties of Patient Reported Outcomes Measurement Information System domains for children with type 1 diabetes.

OBJECTIVE: Patient Reported Outcomes Measurement Information System (PROMIS) includes numerous domains to assess functioning among the pediatric population. These domains, however, have not been evaluated for use in children with type 1 diabetes (T1D). The objective of this study was to determine the measurement properties of PROMIS domains (pain behavior, pain quality, physical stress experience, physical activity, strength impact, and profile-25) in children with T1D. METHODS: This is a cross-sectional study of children with T1Drecruited from tertiary care facilities. To determine construct validity, we compared PROMIS T-scores between known-groups based on (a) glycemic control, hemoglobin A1c (HbA1c%) and (b) self-reported general health, using t test or analysis of variance. Reliability was determined using Cronbach's alpha and item response theory reliability. We also determined agreement between parent-proxy and child self-report PROMIS scores. RESULTS: Our study included 192 children, mean age 12.7 (SD = 2.9) years, eligible to self-report PROMIS surveys. There were significant differences in physical stress experience and pain intensity between children with HbA1c < 10% and those with HbA1c ≥ 10%. There also were significant differences in T-scores for all domains except physical function mobility and strength impact among children with poor/fair, good, very good/excellent general health. All valid domains had reliability >0.70. More than 40% of child-parent pairs were in agreement, with intraclass correlations coefficients (ICC) ranging between 0.41 and 0.63 for all domains, except pain behavior (%agreement = 23%; ICC = 0.29). CONCLUSIONS: Most of the PROMIS domains tested are valid, reliable, and able to differentiate children with T1D who report different general health states. There is moderate agreement between child-parent pairs for all domains except pain behavior.

Recommendation to reality: Closing the transcranial Doppler screening gap for children with sickle cell anemia.

BACKGROUND: Although annual transcranial Doppler (TCD) screening is recommended for children with sickle cell anemia (SCA), compliance is low and variable. Our objective was to utilize an electronic health record (EHR)-based registry to improve TCD adherence among children with SCA, 2-16 years of age, at our institution. METHODS: We developed an in-EPIC real time registry for children with sickle cell disease in year 2016. Since end of year 2016, we have been extracting data quarterly to examine TCD rates and share the list of children who have not received a TCD screen in the past 18 months with the clinical team. The registry also includes a TCD risk score to enhance point of care. We also added Child Life support to increase TCD compliance among children <7 years. Control charts are used to examine TCD rates. RESULTS: At baseline, prior to and start of quarterly data audit and feedback, 63% of children received the recommended annual TCD screen. TCD rates steadily increased to 80% by the third quarter of 2017. We observed a dip in TCD rates, driven by failure of screening young children. Since the initiation of Child Life support for children <7 years, we have sustained TCD screen rates >70%. Overall, our data meet criteria for special cause variation, indicating improvement in TCD rates since 2015. CONCLUSIONS: Regular tracking and identification of patients overdue for a TCD screen using an EHR-based registry resulted in sustained improvement in TCD screening rates. Involvement of Child Life support further improved TCD rates.

The ASH-ASPHO Choosing Wisely Campaign: 5 hematologic tests and treatments to question.

Choosing Wisely is a medical stewardship and quality-improvement initiative led by the American Board of Internal Medicine Foundation in collaboration with leading medical societies in the United States. The American Society of Hematology (ASH) has been an active participant in the Choosing Wisely project. In 2019, ASH and the American Society of Pediatric Hematology/Oncology (ASPHO) formed a joint task force to solicit, evaluate, and select items for a pediatric-focused Choosing Wisely list. By using an iterative process and an evidence-based method, the ASH-ASPHO Task Force identified 5 hematologic tests and treatments that health care providers and patients should question because they are not supported by evidence, and/or they involve risks of medical and financial costs with low likelihood of benefit. The ASH-ASPHO Choosing Wisely recommendations are as follows: (1) avoid routine preoperative hemostatic testing in an otherwise healthy child with no previous personal or family history of bleeding, (2) avoid platelet transfusion in asymptomatic children with a platelet count 10 × 103 /µL unless an invasive procedure is planned, (3) avoid thrombophilia testing in children with venous access-associated thrombosis and no positive family history, (4) avoid packed red blood cells transfusion for asymptomatic children with iron deficiency anemia and no active bleeding, and (5) avoid routine administration of granulocyte colony-stimulating factor for prophylaxis of children with asymptomatic autoimmune neutropenia and no history of recurrent or severe infections. We recommend that health care providers carefully consider the anticipated risks and benefits of these identified tests and treatments before performing them.

Assessment of pediatric asthma exacerbation with the use of new PROMIS measures.

OBJECTIVE: Patient reported outcome measures, such as the Patient Reported Outcomes Measurement Information System (PROMIS) may be used to assess patient functioning for asthma and aid in understanding the impact of asthma exacerbation. These domains may be utilized as endpoints in clinical trials and to guide clinical care. The purpose of this study was to determine psychometric properties of the new PROMIS measures for children with asthma, at baseline and with exacerbation. METHODS: We conducted a cross-sectional analysis of children with acute asthma exacerbation or at baseline health. Psychometric properties of validity (using known groups and correlation) and reliability (using Cronbach's alpha and IRT) for the new PROMIS measures were determined. RESULTS: Our study included 220 subjects, 102 were enrolled during an acute exacerbated state. Cronbach's alpha and IRT reliability was greater or equal to 0.75. Our subjects experiencing an acute exacerbated state reported worse T-scores for pain related domains: pain behavior 45.7 vs 53.5 (p < 0.001), pain quality sensory 44.4 vs 48.5 (p < 0.005), pain quality affective 42.5 vs 51.3 (p < 0.001), and physical stress experience 60.5 vs 65.4 (p < 0.001); and asthma impact 47.9 vs 61.0 (p < 0.001), than subjects at baseline. Child and parent-proxy agreement ranged from 35% to 56%. CONCLUSIONS: The new Pediatric PROMIS domains are valid and reliable for use in children with asthma, for both child-reported and parent-proxy reported outcomes. It was determined that children with acute asthma exacerbation have worse patient reported outcomes (PROs) for the new pain related domains and asthma impact.

Coronavirus Disease among Persons with Sickle Cell Disease, United States, March 20-May 21, 2020.

Sickle cell disease (SCD) disproportionately affects Black or African American persons in the United States and can cause multisystem organ damage and reduced lifespan. Among 178 persons with SCD in the United States who were reported to an SCD-coronavirus disease case registry, 122 (69%) were hospitalized and 13 (7%) died.

Cognitive functioning, patient health communication, and worry mediate pain predictive effects on health-related quality of life in youth with sickle cell disease.

OBJECTIVES: The objective was to investigate the serial mediating effects of perceived cognitive functioning, patient health communication, and disease-specific worry in the relationship between pain and overall generic health-related quality of life (HRQOL) in youth with sickle cell disease (SCD) from the patient perspective. METHODS: The pain, cognitive functioning, communication and worry scales from the Pediatric Quality of Life Inventory (PedsQL) Sickle Cell Disease Module and the PedsQL Multidimensional Fatigue Scale, and the PedsQL 4.0 Generic Core Scales were completed in a multisite national study by 233 youth with SCD of ages 5-18. Hierarchical multiple regression and serial multiple mediator model analyses were conducted to test the mediating effects of perceived cognitive functioning, health communication, and disease-specific worry as intervening variables in the association between the pain predictor variable and overall generic HRQOL. RESULTS: Pain predictive effects on overall generic HRQOL were serially mediated by cognitive functioning, health communication, and disease-specific worry. In predictive analytics models utilizing hierarchical multiple regression analyses with age and gender demographic covariates, pain, cognitive functioning, health communication, and worry accounted for 65% of the variance in patient-reported overall generic HRQOL (P < .001), representing a large effect size. CONCLUSIONS: Perceived cognitive functioning, patient health communication, and disease-specific worry explain in part the mechanism of pain predictive effects on overall generic HRQOL in youth with SCD. Identifying SCD-specific pain, perceived cognitive functioning, health communication, and disease-specific worry as predictor variables of overall generic HRQOL from the patient perspective may inform clinical interventions and future patient-centered clinical research.

Neuropathic pain is associated with poor health-related quality of life in adolescents with sickle cell disease: A preliminary report.

BACKGROUND: Neuropathic pain is associated with poor health-related quality of life (HRQL) in pain conditions other than sickle cell disease (SCD); this relationship in SCD is unknown. We investigated this relationship and hypothesized neuropathic pain is associated with poor HRQL in adolescents with SCD. METHODS: We conducted a cross-sectional study of patients with SCD ages 13-18 years during baseline health. Primary outcome was HRQL, assessed by the PedsQL SCD Module (child self-report, parent proxy report). PedsQL is scored from 0 to 100, with higher scores indicating better HRQL. Neuropathic pain was assessed using the painDETECT questionnaire (scored 0-38); higher scores indicated greater likelihood of neuropathic pain. All completed both PedsQL SCD Module and painDETECT questionnaire. Descriptive statistics were used and associations between painDETECT and PedsQL Total Score, Pain Impact, Pain and Hurt, and Pain Management and Control Scores were determined via Pearson correlation. Significance was P < .05. RESULTS: Twelve patients were enrolled. Median (interquartile range [IQR]) age was 15 (14-16.5) years, 75% were female, and 83% were on hydroxyurea. Higher painDETECT scores were significantly associated with lower PedsQL SCD Module child self-report Pain and Hurt Scores (r = -0.68, P = .01). Higher painDETECT scores were also significantly associated with lower PedsQL parent proxy-report Total Scores (r = -0.64, P = .03) and Pain and Hurt Scores (r = -0.67, P = .02). CONCLUSIONS: These data suggest that adolescents with SCD and neuropathic pain have poor HRQL even in their baseline state of health. Prospective, larger studies are needed to confirm this preliminary finding and explore a multimodal approach for pain assessment in SCD.

Can PROMIS domains of pain and physical functioning detect changes in health over time for children with sickle cell disease?

BACKGROUND: The Patient-Reported Outcomes Measurement Information System (PROMIS) includes multiple domains that measure pain and physical functioning which are valid and reliable for use in children with sickle cell disease. The responsiveness of these measures to detect changes in health status over time among children with sickle cell disease is unknown. PROCEDURE: We conducted a prospective cohort study of children presenting to emergency department (ED) with vaso-occlusive crises. Children completed PROMIS surveys in the ED and at two follow-up time points (7-10 days and 1-3 months) after their acute care visit. Linear mixed models were used to determine if there were significant changes in PROMIS T scores over time. We used a patient's global assessment of change in pain question to anchor the changes in PROMIS scores (mean and 95% confidence interval). A change was considered statistically significant if the 95% CI did not include 0. RESULTS: We found that patients improved significantly in all domains 1 to 3 months after discharge from an acute care visit for pain. In addition, the pain and physical stress experience domains were responsive to change 7 to 10 days after discharge. Using the anchor of change in pain, for children who had considerable improvement in pain, there were significant changes in PROMIS T scores ranging from 6 to 15. CONCLUSIONS: Relevant PROMIS domains detect changes in children experiencing acute vaso-occlusive crises. These domains can be used in research and clinic settings to measure clinically relevant change in children with sickle cell disease.

A Multiyear Cross-sectional Study of Guideline Adherence for the Timeliness of Opioid Administration in Children With Sickle Cell Pain Crisis.

STUDY OBJECTIVE: The National Heart, Lung, and Blood Institute evidence-based guidelines for timeliness of opioid administration for sickle cell disease (SCD) pain crises recommend an initial opioid within 1 hour of arrival, with subsequent dosing every 30 minutes until pain is controlled. No multisite studies have evaluated guideline adherence, to our knowledge. Our objective was to determine guideline adherence across a multicenter network. METHODS: We conducted a multiyear cross-sectional analysis of children with SCD who presented between January 1, 2016, and December 31, 2018, to 7 emergency departments (EDs) within the Pediatric Emergency Care Applied Research Network. Visits for uncomplicated pain crisis were included, defined with an International Classification of Diseases, Ninth Revision (ICD-9) and ICD-10 code for SCD crisis and receipt of an opioid, excluding visits with other SCD complications or temperature exceeding 38.5°C (101.3°F). Times were extracted from the electronic record. Guideline adherence was assessed across sites and calendar years. RESULTS: A total of 4,578 visits were included. The median time to first opioid receipt was 62 minutes (interquartile range 42 to 93 minutes); between the first and second opioid receipt, 60 minutes (interquartile range 39 to 93 minutes). Overall, 48% of visits (95% confidence interval 47% to 50%) were guideline adherent for first opioid. Of 3,538 visits with a second opioid, 15% (95% confidence interval 14% to 16%) were guideline adherent. Site variation in adherence existed for time to first opioid (range 22% to 70%) and time between first and second opioid (range 2% to 36%; both P<.001). There was no change in timeliness to first dose or time between doses across years (P>.05 for both). CONCLUSION: Guideline adherence for timeliness of SCD treatment is poor, with half of visits adherent for time to first opioid and one seventh adherent for second dose. Dissemination and implementation research/quality improvement efforts are critical to improve care across EDs.

Youth Victims of Violence Report Worse Quality of Life Than Youth With Chronic Diseases.

OBJECTIVES: Measuring health-related quality of life (HRQOL) provides the patient's perspective of his/her well-being and offers a unique outcome measure to demonstrate the impact of violence on the victim. To date, no study has described HRQOL in youth victims of violence in the United States. The purpose of this study was to describe HRQOL in youth victims of violence as compared with healthy youth and youth with chronic disease. METHODS: We conducted an exploratory cross-sectional study of the HRQOL of victims of violence aged 8 to 18 years. Descriptive statistics were reported for participant and injury demographics. One sample t tests were used to compare the sample population's HRQOL to known HRQOL of healthy populations and specific disease populations. RESULTS: Fifty-eight victims of violence participated in the study. Youth victims of violence had significantly worse mean HRQOL scores (mean, 71.4) compared with healthy youth in overall functioning (mean, 83.9), P < 0.001. Youth victims of violence reported worse psychosocial (mean, 67.6), emotional (mean, 62.9), and school (mean, 63.8) functioning than youth with obesity (mean, 72.1, 68.6, 75.0, respectively) and cancer (mean, 72.1, 72.2, 68.3, respectively). Mean Patient-Reported Outcomes Measurement Information System T scores for youth victims of violence were significantly worse in anxiety (T = 51.9) and depression (T = 52.4) compared with youth with obesity (T = 48.3, 49.2), cancer (T = 47.7, 47.6), and sickle cell disease (T = 43, 44). CONCLUSIONS: Youth victims of violence suffer significant impairment in HRQOL compared with healthy populations and youth with specific disease burdens. Future studies into violence prevention effectiveness should use HRQOL as a comparative outcome measure to better tailor post injury management and interventions.

Parent Preferences Regarding Home Oxygen Use for Infants with Bronchopulmonary Dysplasia.

OBJECTIVES: To determine parent preferences for discharge with home oxygen in infants with bronchopulmonary dysplasia. STUDY DESIGN: This was a prospective study of parents of infants born at <32 weeks' gestation with established bronchopulmonary dysplasia and approaching neonatal intensive care unit (NICU) discharge. Parents were presented a hypothetical scenario of an infant who failed weaning to room air and 2 options: discharge with home oxygen or try longer to wean oxygen. The initial scenario risks reflected a 1.5-week difference in NICU length of stay and no differences in other outcomes. Length of stay and readmission outcomes were increased or decreased until the parent switched preference. Three months after discharge, parents were asked to reconsider their preference. Differences were analyzed by χ2 or Kruskal-Wallis tests. RESULTS: Of 125 parents, 50% preferred home oxygen. For parents preferring home oxygen, the most important reason was comfort at home (79%). Forty percent switched preference when the length of stay difference decreased by 1 week; 35% switched when readmission increased by 5%. For parents preferring to stay in NICU, the most important reason was fear of taking care of the child at home (73%). Thirty-two percent switched preference when the length of stay difference increased by 1 week; 31% switched when readmission decreased by 5%. One hundred ten parents completed the 3-month follow-up; 80 were discharged with home oxygen. Seventy-eight percent would prefer home oxygen (97% who initially preferred home oxygen and 60% who initially preferred to stay in the NICU). CONCLUSIONS: Parents weigh differences in NICU length of stay and readmission risk similarly. After discharge, most prefer earlier discharge with home oxygen. Earlier education to increase comfort with home technology may facilitate NICU discharge planning.

A Prospective Study of Parent Health-Related Quality of Life before and after Discharge from the Neonatal Intensive Care Unit.

OBJECTIVE: To determine how infant illness and parent demographics are associated with parent health-related quality of life (HRQL) during and 3 months after hospitalization in the neonatal intensive care unit (NICU). We hypothesized that parents of extremely preterm infants would report lower NICU HRQL than other parents, and that all parents would report improved HRQL after discharge. STUDY DESIGN: This prospective study of parent-infant dyads admitted to a level IV NICU for ≥14 days from 2016 to 2017 measured parent HRQL before and 3 months after discharge using the Pediatric Quality of Life Inventory Family Impact Module. Multivariable regression was used to identify risk factors associated with HRQL differences during hospitalization and after discharge. RESULTS: Of the 194 dyads, 167 (86%) completed the study (24% extremely preterm; 53% moderate to late preterm; 22% term). During the NICU hospitalization, parents of extremely preterm infants reported lower adjusted HRQL (-7 points; P = .013) than other parents. After discharge, parents of extremely preterm infants reported higher HRQL compared with their NICU score (+10 points; P = .001). Tracheostomy (-13; P = .006), home oxygen (-6; P = .022), and readmission (-5; P = .037) were associated with lower parent HRQL 3 months after discharge, adjusted for NICU HRQL score. CONCLUSIONS: Parents of extremely preterm infants experienced a greater negative impact on HRQL during the NICU hospitalization and more improvement after discharge than parents of other infants hospitalized in the NICU. Complex home care was associated with lower parent HRQL after discharge. The potential benefit of home discharge should be balanced against the potential negative impact of complex home care.

Use of the new pediatric PROMIS measures of pain and physical experiences for children with sickle cell disease.

BACKGROUND: There are new pediatric domains to measure patients' pain and physical experiences in the Patient-Reported Outcomes Measurement Information System (PROMIS). The objective of this study was to establish the psychometric properties of these domains for children with sickle cell disease (SCD). PROCEDURE: We conducted a cross-sectional analysis of PROMIS assessments of children with SCD recruited from a pediatric tertiary care clinic. Validity of the new PROMIS domains was determined by comparing scores between known groups and describing their correlations with previously validated PROMIS measures. Cronbach's alpha and item response theory (IRT) reliability were used to assess internal consistency reliability. Agreement between parent-proxy and child self-report was determined for all domains. RESULTS: Our study included 164 subjects, of whom 117 were eligible to self-report. The mean T-scores for physical stress experience, strength impact, pain behavior, and pain quality sensory scores were significantly different between children who used pain medications in the prior week and those who did not. There were also differences in T-scores across children reporting mild, moderate, and severe pain on the pain intensity scale. All measures had Cronbach's alpha and IRT reliability > 0.80. The percentage of agreement between child and parent-proxy PROMIS domains ranged from 36% to 60% depending on the domain. CONCLUSIONS: The new PROMIS domains of physical stress experience, strength impact, pain behavior, and pain quality sensory domains are valid and reliable for children with SCD. The low-moderate agreement between parent-proxy and child self-report scores support the complementary information provided by the two perspectives.

Longitudinal Trend in Emergency Department Reliance for Pain Among Sickle Cell Disease Patients in Wisconsin.

Patients with sickle cell disease frequently visit the emergency department for pain. The metric of emergency department reliance (EDR) describes emergency department utilization in relation to all ambulatory visits and serves as a quality of care indicator. This study uses Wisconsin Medicaid data from 2011 to 2015 to examine trend of EDR for pain over the period of 5 years. We stratified our cohort (N=750) by patient ages into 4 groups: (1) children; (2) transition group; (3) young adults; and (4) adults. Using a linear mixed model, we estimated longitudinal trends adjusting for age group and hydroxyurea possession calculated as medication possession ratio. Results show that EDR for pain has distinct temporal patterns for each group. EDR for pediatrics continually remained less than the established threshold of 0.33. The EDR for transition group significantly increased over time; however, the EDR for young adults has significantly decreased since 2011. There were no significant differences in EDR over time for adults older than 30 years. Overall, increase in medication possession ratio was associated with lower EDR. The low EDR for pain among children and the improvements among adults indicate the success of efforts for sickle cell disease patients. However, further interventions are needed for the transition age group.

A trial of unrelated donor marrow transplantation for children with severe sickle cell disease.

Children with sickle cell disease experience organ damage, impaired quality of life, and premature mortality. Allogeneic bone marrow transplant from an HLA-matched sibling can halt disease progression but is limited by donor availability. A Blood and Marrow Transplant Clinical Trials Network (BMT CTN) phase 2 trial conducted from 2008 to 2014 enrolled 30 children aged 4 to 19 years; 29 were eligible for evaluation. The primary objective was 1-year event-free survival (EFS) after HLA allele-matched (at HLA-A, -B, -C, and -DRB1 loci) unrelated donor transplant. The conditioning regimen included alemtuzumab, fludarabine, and melphalan. Graft-versus-host disease (GVHD) prophylaxis included calcineurin inhibitor, short-course methotrexate, and methylprednisolone. Transplant indications included stroke (n = 12), transcranial Doppler velocity >200 cm/s (n = 2), ≥3 vaso-occlusive pain crises per year (n = 12), or ≥2 acute chest syndrome episodes (n = 4) in the 2 years preceding enrollment. Median follow-up was 26 months (range, 12-62 months); graft rejection was 10%. The 1- and 2-year EFS rates were 76% and 69%, respectively. The corresponding rates for overall survival were 86% and 79%. The day 100 incidence rate of grade II-IV acute GVHD was 28%, and the 1-year incidence rate of chronic GVHD was 62%; 38% classified as extensive. There were 7 GVHD-related deaths. A 34% incidence of posterior reversible encephalopathy syndrome was noted in the first 6 months. Although the 1-year EFS met the prespecified target of ≥75%, this regimen cannot be considered sufficiently safe for widespread adoption without modifications to achieve more effective GVHD prophylaxis. The BMT CTN #0601 trial was registered at www.clinicaltrials.gov as #NCT00745420.

Hydroxycarbamide in children with sickle cell anaemia after first-dose vs. chronic therapy: pharmacokinetics and predictive models for drug exposure.

AIMS: The purposes of this work were to: (1) compare pharmacokinetic (PK) parameters for hydroxycarbamide in children receiving their first dose (HCnew ) vs. those receiving chronic therapy (HCchronic ), (2) assess the external validity of a published PK dosing strategy, and (3) explore the accuracy of dosing strategies based on a limited number of HC measurements. METHODS: Utilizing data from two prospective, multicenter trials of hydroxycarbamide (Pharmacokinetics of Liquid Hydroxyurea in Pediatric Patients with Sickle Cell Anemia; NCT01506544 and Single-Dose (SD) and Steady-State (SS) Pharmacokinetics of Hydroxyurea in Children and Adolescents with Sickle Cell Disease), plasma drug concentration vs. time profiles were evaluated with a model independent approach in the HCnew and HCchronic groups. Various predictive scenarios were analysed to evaluate whether systemic exposure with hydroxycarbamide could be accurately predicted. RESULTS: Absorption of hydroxycarbamide was rapid, variable and dose independent. Dose-normalized peak plasma concentrations and drug exposure (AUC) were higher, and weight-normalized apparent oral clearance was lower in the HCnew group. We assessed a PK-guided dosing strategy along with other predictive scenarios and found that inclusion of plasma samples only slightly improved the accuracy of AUC predictions when compared to a population-based method. CONCLUSIONS: Children naïve to hydroxycarbamide exhibit a different PK profile compared to children receiving chronic therapy. Accuracy of population-based dosing is sufficient to target AUCs in individual patients. Further clearance/bioavailability studies are needed to address the factors responsible for variability in the disposition of hydroxycarbamide.