Gene Therapy in Hemophilia A: Achievements, Challenges, and Perspectives.

Strides in advancements of care of persons with hemophilia include development of long-acting factor replacement therapies, novel substitution and hemostatic rebalancing agents, and most recently approved gene therapy. Several decades of preclinical and clinical trials have led to development of adeno-associated viral (AAV) vector-mediated gene transfer for endogenous production of factor VIII (FVIII) in hemophilia A (HA). Only one gene therapy product for HA (valoctocogene roxaparvovec) has been approved by regulatory authorities. Results of valoctocogene roxaparvovec trial show significant improvement in bleeding rates and use of factor replacement therapy; however, sustainability and duration of response show variability with overall decline in FVIII expression over time. Further challenges include untoward adverse effects involving liver toxicity requiring immunosuppression and development of neutralizing antibodies to AAV vector rendering future doses ineffective. Real-life applicability of gene therapy for HA will require appropriate patient screening, infrastructure setup, long-term monitoring including data collection of patient-reported outcomes and innovative payment schemes. This review article highlights the success and development of HA gene therapy trials, challenges including adverse outcomes and variability of response, and perspectives on approach to gene therapy including shared decision-making and need for future strategies to overcome the several unmet needs.

Mobile Application Measurement of Menstrual Cycle Characteristics and Their Association with Dysmenorrhea and Activity Limitation in Early Adolescents.

OBJECTIVE: Real-time tracking of menstrual bleeding is a barrier to research due to limitations with traditional data collection tools. This prospective cohort study utilized a mobile application (TDot app) in young adolescents aged 10-14 years to assess the relationship between heavy menstrual bleeding (HMB), dysmenorrhea, and activity limitation. METHODS: Menstrual cycles were captured over six months in real-time using the Pictorial Blood loss Assessment Chart (PBAC). A median PBAC score of >100 was used to identify participants with HMB. Participants also completed a modified WaLIDD (Working ability, Location, Intensity, Days of pain, Dysmenorrhea) scale. Impact of menses on daily activities was collected for each cycle. RESULTS: A total of 160 participants enrolled and 100 (63%) participants with ≥3 cycles recorded in the mobile app were analyzed. HMB was noted in 41% of participants. Median modified WaLIDD score was significantly higher in participants with HMB than those without HMB (p=0.01). No significant differences were found in activity limitations between participants with and without HMB (p=0.34). Median modified WaLIDD score for participants with activity limitation was significantly higher than those without activity limitation (p=0.01). CONCLUSION: Utilizing mobile app technology, we were able to gather real-time menstrual outcome data from young adolescents on heaviness of flow, dysmenorrhea and activity limitations. While we did not find that patients with HMB were more likely to have activity limitations, we did find that those with limitations had modestly higher dysmenorrhea scores. Future studies should focus on identifying additional variables that impact activity limitation during menstruation.

Comparison of thromboembolism outcomes in patients with sickle cell disease prescribed hormonal contraception.

Patients with sickle cell disease (SCD) are at a risk of thromboembolism (TE), and use of hormonal contraception can further increase that risk. This study aims to assess patterns of hormonal contraceptive use and compare risk of contraception-related TE between combined hormonal contraceptives (CHCs) and progestin-only contraceptives (POCs). Patients with SCD aged between 12 and 44 years with a new prescription of a hormonal contraceptive in the Centers for Medicare and Medicaid Services Medicaid Analytic eXtract database (2006-2018) were followed up to 1 year. We identified 7173 new users: 44.6% initiated CHC and 55.4% initiated POC. Combined oral contraceptive pills (OCPs; 36.5%) and progestin-only depot medroxyprogesterone acetate (33.9%) were the most frequently prescribed agents. A total of 1.8% of contraception users had a new diagnosis of TE within 1 year of the first identified contraception prescription. There were no significant differences in TE event rates between CHC and POC users (17.2 and 24.7 events per 1000 person-years, respectively). In patients prescribed OCP, there were no differences in TE event rates based on estrogen dose or progestin generation. Transdermal patch had a 2.4-fold increased risk of TE as compared with that of OCP. Although limited by the retrospective study design and use of administrative claims data, this study found no significant differences in TE rates between new users of CHC and POC in patients with SCD. Careful evaluation of underlying TE risk factors should be considered for each patient with SCD before initiation of hormonal contraception.

Prevalence and risk factors for pulmonary embolism in children with sickle cell disease: an institutional retrospective cohort study.

The study was conducted to examine prevalence of pulmonary embolism in children with sickle cell disease (SCD) and identify potential risk factors associated with pulmonary embolism in a single tertiary paediatric centre. Children with SCD between 0 and 21 years of age from January 2010 to January 2021 were included. Pulmonary embolism was initially identified using International Classification of Diseases (ICD)-9 or 10 codes and confirmed with manual chart review of identified cases. Logistic regression analysis was performed to assess association between SCD specific and general thrombotic risk factors and pulmonary embolism. We identified 492 unique patients with SCD with a median age of 11 years (interquartile range: 4-18). A total of eight (1.6%) patients developed a pulmonary embolism. Patients with pulmonary embolism were significantly older (median, interquartile range: 20.5, 14-21 years) than patients without pulmonary embolism (median, interquartile range: 10, 4-17 years). Central nervous system (CNS) vasculopathy and erythrocytapheresis were significantly associated with pulmonary embolism on univariable logistic regression analysis. A previous diagnosis of deep vein thrombosis (DVT) was significantly more common among patients with pulmonary embolism than among those without pulmonary embolism (50 vs. 5.2%; P  < 0.0001). Prevalence of pulmonary embolism in children with SCD was high. Risk factors associated with pulmonary embolism in this study such as CNS vasculopathy or erythrocytapheresis could suggest that the risk for pulmonary embolism in SCD may be related to the severity of disease state. Future studies are needed on pulmonary embolism prevention strategies.

Prevalence and Risk Factors for Pulmonary Embolism in Pediatric Sickle Cell Disease: A National Administrative Database Study.

Patients with sickle cell disease (SCD) have a high risk for venous thromboembolism which is associated with increased risk of mortality. Studies examining risk of pulmonary embolism (PE) in children with SCD are lacking. This study was conducted in children with SCD between 0-21 years of age using a nationwide administrative database in the United States- Pediatric Health Information System (PHIS) from January 2010 to June 2021. Diagnostic codes and imaging, procedure, and pharmaceutical billing codes were used to identify PE and potential clinical, demographic, and utilization risk factors. Logistic regression analyses were performed to assess association between risk factors and PE. We identified 22,631 unique patients with SCD with a median age of 10.8 years (range: <0.1-20.9). A total of 120 (0.53%) patients developed a PE with median age of 17.4 years (range: 6.6-20.9) at PE diagnosis. Patients with PE had longer hospitalization and more frequent ICU admissions than patients without PE (p < 0.001). Risk factors significantly associated with PE on multivariable analysis included older age, prior history of central venous line (CVL), acute chest syndrome, and apheresis. Mortality was not significantly different between those with and without PE. The prevalence of PE in hospitalized children with SCD was estimated to be 0.53%. Patients with PE had higher healthcare utilization characteristics. Factors significantly associated with PE suggest that the risk for PE in SCD may be related to the severity of disease state. Future trials are needed for risk stratification and PE prevention strategies in children with SCD.

Prevalence of Bacteremia in Febrile Patients With Sickle Cell Disease: Meta-Analysis of Observational Studies.

OBJECTIVE: Pneumococcal vaccination has decreased the bacteremia rate in both the general pediatric and sickle cell disease (SCD) populations. Despite this decrease, and an increasing concern for antibiotic resistance, it remains standard practice to obtain blood cultures and administer antibiotics in all febrile (>38.5°C) patients with SCD. We conducted a systematic review and meta-analysis of the available studies of the prevalence of bacteremia in febrile patients with SCD. METHODS: We searched the medical literature up to November 2018 in PUBMED, EMBASE, and Web of Science with terms epidemiology, prevalence, bacteremia, and sickle cell anemia. We only included studies with patients after 2000, when the pneumococcal 7-valent conjugate (PCV7) vaccine became widely available. The prevalence of bacteremia [95% confidence interval (CI)] was calculated by dividing the number of positive blood cultures by the number of febrile episodes. The I2 statistic measured heterogeneity between prevalence estimates. Bias in our studies was quantified by the Newcastle-Ottawa Quality Assessment Scale. RESULTS: Our search identified 228 citations with 10 studies meeting our inclusion/exclusion criteria. The weighted prevalence of bacteremia across all studies was 1.9% (95% CI, 1.22%-2.73%), and for Streptococcus pneumoniae bacteremia, it was 0.31% (95% CI, 0.16%-0.50%). Risks for bacteremia except central lines could not be determined because of the low prevalence of the outcome. CONCLUSIONS: There appears to be a need to develop a risk stratification strategy to guide physicians to manage febrile patients with SCD based on factors including, but not limited to, history and clinical examination, vaccination status, use of prophylactic antibiotics, laboratory values, likely source of infection, and accessibility to health care.

Use of Telehealth to Enhance Care in a Family-Centered Childhood Obesity Intervention.

Family-centered childhood obesity interventions have been found to be effective. We describe the use of telehealth for tailored behavior change support in a family-centered randomized trial. Children of 2 to 12 years with body mass index ≥85th percentile were randomized to Enhanced Primary Care (EPC) or Enhanced Primary Care + Coaching (EPC + C). EPC + C received 6 health coach visits (in-person or by video or phone call) over 1 year. Telehealth modalities included interactive text messaging, video calls, and an online community resource map. There were 360 children randomized to the EPC + C arm; 87% of parents completed ≥1 health coaching contacts. Overall, 93% parents were sent text messages of which 99% responded at least once. About 72% parents were very satisfied with the message content and 97% were satisfied with information provided about community health resources. The high level of participant engagement and satisfaction suggests that telehealth is feasible and acceptable in family-centered childhood obesity programs.

In-hospital mortality of hematopoietic stem cell transplantation among children with nonmalignancies: A nationwide study in the United States from 2000 to 2012.

BACKGROUND: Hematopoietic stem cell transplant (HSCT) can cure or alleviate a wide range of nonmalignant childhood conditions. However, few studies have examined longitudinal national trends of frequency or short-term complications of HSCT before 2006 when an HSCT became a reportable procedure by US law. By using a US nationally representative database, we conducted nationwide longitudinal analyses on demographics, in-hospital mortality, and short-term complications in nonmalignant HSCT from 2000 to 2012. PROCEDURE: We analyzed 2504 admissions for children < 20 years old who underwent an allogeneic HSCT for a nonmalignant condition by using the Kids' Inpatient Database for the years 2000, 2003, 2006, 2009, and 2012. Changes in in-hospital mortality and other outcomes were assessed over the study period using weighted analyses, which enabled generation of national estimates in each year. RESULTS: The number of admissions for HSCT increased from 334 to 667 from 2000 to 2012, respectively; among them, the use of bone marrow decreased (66.5% to 34.1%, P < 0.001). In-hospital mortality declined (13.4% to 7.1%, P = 0.04), as did bacteremia (28.7% to 10.1%, P < 0.001) and vascular catheter infections (18.8% to 8.7%, P = 0.006), but cytomegalovirus infections increased (4.9% to 15.9%, P < 0.001), as did adenovirus infections (1.8% to 6.9%, P < 0.001) from 2000 to 2012. CONCLUSION: Population-based analyses demonstrated a substantial expansion of the utilization of HSCT occurred for pediatric nonmalignancies from 2000 to 2012 in the United States, whereas the in-hospital mortality declined by approximately a half. Further research is needed to identify distinct contributing factors.