Pharmacokinetic-guided hydroxyurea to reduce transfusions in Ugandan children with sickle cell anemia: study design of the Alternative Dosing And Prevention of Transfusions (ADAPT) trial.

INTRODUCTION: People with sickle cell anemia (SCA) may require frequent blood transfusions to treat acute and chronic complications. Hydroxyurea is a life-saving treatment for SCA that could also decrease the need for blood transfusions. Inadequate medication access and challenges in dose optimization limit the widespread use of hydroxyurea in Africa. If feasible, pharmacokinetic (PK) dosing might improve dose determination to minimize toxicities and maximize clinical benefits. The Alternative Dosing And Prevention of Transfusions (ADAPT, NCT05662098) trial will analyze the impact of hydroxyurea on transfusion rate and serve as a pilot study to evaluate the feasibility of PK-guided hydroxyurea dosing in Uganda. METHODS: Herein we describe the rationale and design of ADAPT, a prospective cohort study of ~100 children with SCA in Jinja, Uganda. The primary hypothesis is that hydroxyurea will decrease blood transfusion use by ≥50%, comparing the transfusion incidence rate ratio between a 3-month pre-treatment and a 12-month treatment period. A key secondary hypothesis is that our PK-dosing approach will generate a suitable hydroxyurea dose for ≥80% of participants. Every ADAPT participant will undergo hydroxyurea PK testing, and if a dose is generated within 15-35 mg/kg/day participants will start on their individualized dose. If not, they will start on a default dose of 20 mg/kg/day. Hydroxyurea dose optimization will occur with periodic dose adjustments. CONCLUSION: Overall, demonstrating the reduction in blood transfusion utilization with hydroxyurea treatment would provide leverage to increase hydroxyurea access, and PK-guided hydroxyurea dosing should optimize the safe and effective treatment of SCA across sub-Saharan Africa.

Reducing transfusion utilization for children with sickle cell anemia in sub-Saharan Africa with hydroxyurea: Analysis from the phase I/II REACH trial.

Children with sickle cell anemia (SCA) in Africa frequently require transfusions for SCA complications. Despite limited blood supplies, strategies to reduce their transfusion needs have not been widely evaluated or implemented. We analyzed transfusion utilization in children with SCA before and during hydroxyurea treatment. REACH (Realizing Effectiveness Across Continents with Hydroxyurea, NCT01966731) is a longitudinal Phase I/II trial of hydroxyurea in children with SCA from Angola, Democratic Republic of Congo, Kenya, and Uganda. After enrollment, children had a two-month pre-treatment screening period followed by 6 months of fixed-dose hydroxyurea (15-20 mg/kg/day), 18 months of dose escalation, and then stable dosing at maximum tolerated dose (MTD). Characteristics associated with transfusions were analyzed with univariate and multivariable models. Transfusion incidence rate ratios (IRR) across treatment periods were calculated. Among 635 enrolled children with 4124 person-years of observation, 258 participants (40.4%) received 545 transfusions. The transfusion rate per 100 person-years was 43.2 before hydroxyurea, 21.7 on fixed-dose, 14.5 during dose escalation, and 10.8 on MTD. During MTD, transfusion incidence was reduced by 75% compared to pre-treatment (IRR 0.25, 95% confidence interval [CI] 0.18-0.35, p < .0001), and by 50% compared to fixed dose (IRR 0.50, 95% CI 0.39-0.63, p < .0001). Hydroxyurea at MTD decreases transfusion utilization in African children with SCA. If widely implemented, universal testing and hydroxyurea treatment at MTD could potentially prevent 21% of all pediatric transfusions administered in sub-Saharan Africa. Increasing hydroxyurea access for SCA should decrease the transfusion burden and increase the overall blood supply.

Rationale, Development, and Validation of HdxSim, a Clinical Decision Support Tool for Model-Informed Precision Dosing of Hydroxyurea for Children with Sickle Cell Anemia.

Hydroxyurea treatment for children with sickle cell anemia (SCA) is effective and life-saving. Stepwise escalation to maximum tolerated dose (MTD) provides optimal benefits, but is logistically challenging and time-consuming, especially in low-income countries where most people with SCA live. Model-informed precision dosing (MIPD) of hydroxyurea expedites MTD determination and improves outcomes compared with trial-and-error dose adjustments. HdxSim, a user-friendly, online, clinical decision support tool was developed to facilitate hydroxyurea MIPD and evaluated using real-world pharmacokinetic (PK) data. First-dose hydroxyurea PK profiles were analyzed from two clinical trial datasets (Hydroxyurea Study of Long-Term Effects (HUSTLE), NCT00305175 and Therapeutic Response Evaluation and Adherence Trial (TREAT), NCT02286154). Areas under the concentration-time curve (AUC) estimated by HdxSim were compared with those determined using traditional trapezoidal methodology and PK software (MWPharm-DOS). The doses predicted by HdxSim and MWPharm-DOS were compared with the observed clinical MTD. For HUSTLE participants, HdxSim accurately estimated hydroxyurea AUC compared with the trapezoidal method, with < 20% variance. The average (mean ± SD) AUC for TREAT participants estimated with HdxSim (68.6 ± 18.0 mg*hour/L) was lower than MWPharm-DOS (78.6 ± 20.7 mg*hour/L, P = 0.012), but the average recommended doses were not different (425 vs. 423 mg/day, P = 0.97). Moreover, HdxSim was non-inferior to MWPharm-DOS at predicting clinical MTD (absolute difference 3.9 ± 5.8 vs. 4.9 ± 8.2 mg/kg/day, P = 0.19). HdxSim accurately estimates hydroxyurea exposure and is noninferior to traditional PK approaches at predicting the clinical hydroxyurea MTD. Hydroxyurea dosing based on target exposure leads to improved outcomes in children with SCA, and has the potential to make PK-guided hydroxyurea dosing more accessible to this neglected population globally.

Hydroxyurea pharmacokinetics and precision dosing in low-resource settings.

Introduction: Hydroxyurea is effective disease-modifying treatment for sickle cell anemia (SCA). Escalation to maximum tolerated dose (MTD) achieves superior benefits without additional toxicities, but requires dose adjustments with serial monitoring. Pharmacokinetic (PK)-guided dosing can predict a personalized optimal dose, which approximates MTD and requires fewer clinical visits, laboratory assessments, and dose adjustments. However, PK-guided dosing requires complex analytical techniques unavailable in low-resource settings. Simplified hydroxyurea PK analysis could optimize dosing and increase access to treatment. Methods: Concentrated stock solutions of reagents for chemical detection of serum hydroxyurea using HPLC were prepared and stored at -80C. On the day of analysis, hydroxyurea was serially diluted in human serum, then spiked with N-methylurea as an internal standard and analyzed using two commercial HPLC machines: 1) standard benchtop Agilent with 449 nm detector and 5 micron C18 column; and 2) portable PolyLC with 415 nm detector and 3.5 micron C18 column. After validation in the United States, the portable HPLC and chemicals were transported to Tanzania. Results: A calibration curve using hydroxyurea 2-fold dilutions ranging from 0 to 1000 µM was plotted against the hydroxyurea:N-methylurea ratio. In the United States, both HPLC systems yielded calibration curves with R2 > 0.99. Hydroxyurea prepared at known concentrations confirmed accuracy and precision within 10%-20% of the actual values. Both HPLC systems measured hydroxyurea with <10% variance from the prepared concentrations, and paired analysis of samples on both machines documented <15% variance. Serial measurements of 300 and 100 µM concentrations using the PolyLC system were precise with 2.5% coefficient of variance. After transport to Tanzania with setup and training, the modified PolyLC HPLC system produced similar calibration curves with R2 > 0.99. Conclusion: Increasing access to hydroxyurea for people with SCA requires an approach that eases financial and logistical barriers while optimizing safety and benefits, especially in low-resource settings. We successfully modified a portable HPLC instrument to quantify hydroxyurea, validated its precision and accuracy, and confirmed capacity building and knowledge transfer to Tanzania. HPLC measurement of serum hydroxyurea is now feasible in low-resource settings using available laboratory infrastructure. PK-guided dosing of hydroxyurea will be tested prospectively to achieve optimal treatment responses.

Clinical Characteristics and Short-Term Outcomes of Children With Asparaginase-Associated Pancreatitis.

OBJECTIVES: Acute pancreatitis is a significant toxicity of l-asparaginase, a chemotherapeutic agent used to treat acute lymphoblastic leukemia. This case series describes the short-term clinical course and disposition of patients who developed asparaginase-associated pancreatitis (AAP) at one quaternary pediatric center. METHODS: Clinical data, including laboratory data, inpatient and intensive care unit (ICU) days, imaging findings, presence of complications such as need for ventilation, dialysis, and the development of pleural effusions, and mode of nutrition were abstracted from the medical record of patients with AAP. Pediatric criteria were used to classify episode severity based on the development of organ failure and local complications, such as pancreatic necrosis. RESULTS: Between 2005 and 2015, 34 patients had AAP with 43 distinct episodes of pancreatitis. The median inpatient length of stay was 10 days (range 2-65). Seven episodes (16.3%) required intensive care unit (ICU)-level care. Seventeen episodes (39.5%) were severe based on the development of organ failure or presence of pancreatic necrosis. Total parenteral nutrition (TPN) was used in 17 episodes (39.5%); for 34 episodes (79.1%), patients were discharged on entirely oral feeds. Antibiotics were administered in 20 episodes (46.5%). Pancreatic necrosis was identified within the first week in 12 episodes (27.9%). There were no deaths due to AAP. CONCLUSIONS: The clinical course varies widely among patients with AAP. Over one-third of the patients in this series developed severe pancreatitis. Although the prognosis of AAP is generally good, many patients develop systemic complications of AAP, requiring TPN or ICU-level care.

Racial and ethnic disparities among children with primary central nervous system tumors in the US.

INTRODUCTION: Primary central nervous system (CNS) tumors are among the most common and lethal types of cancer in children. However, the existence of health disparities in CNS tumors by race or ethnicity remains poorly understood. This systematic review sought to determine whether racial and ethnic disparities in incidence, healthcare access, and survival exist among pediatric patients diagnosed with CNS tumors. METHODS: A search of MEDLINE, Embase, CINAHL, Web of Science, and Scopus was conducted. Inclusion criteria selected for studies published between January 1, 2005 and July 15, 2020 that focused on pediatric populations in the US, evaluated for potential differences based on racial or ethnic backgrounds, and focused on CNS tumors. A standardized study form was used to collect study information, population of interest, research design, and quality of analysis, sample size, participant demographics, pathology evaluated, and incidence or outcomes observed. RESULTS: A total of 30 studies were inlcuded. Studies suggest White children may be more likely to be diagnosed with a CNS tumor and Hispanic children to present with advanced-stage disease and have worse outcomes. The degree of influence derived from socioeconomic factors is unclear. This review was limited by few available studies that included race and ethnicity as a variable, the overlap in databases used, and unclear categorization of race and ethnicity. CONCLUSIONS: This review identified notable and at times contradicting variations in racial/ethnic disparities among children with CNS tumors, suggesting that the extent of these disparities remains largely unknown and prompts further research to improve health equity.

Household material hardships impact emergency department reliance in pediatric patients with sickle cell disease.

BACKGROUND: In sickle cell disease (SCD), high emergency department (ED) utilization is associated with worse outcomes and increased costs. A metric called ED reliance (EDr), the percentage of healthcare visits that occur in the ED, attempts to identify ED overutilization. It is unknown if household material hardships (HMH)-housing, utility, or food insecurity-impact reliance on the ED. As these may represent modifiable risk factors for high ED utilization, we aimed to estimate the association between HMH and EDr in pediatric patients with SCD. METHODS: We reviewed the electronic medical records of pediatric patients with SCD who received care in the Boston Medical Center network in Massachusetts, USA, to collect data on HMH and healthcare utilization. Using linear regression to control for potential confounders, we modeled the association between material hardships and EDr. RESULTS: Of 101 eligible patients, 60 (59%) reported one or more HMH. The mean EDr was 12% overall, with significant differences between those with and without HMH (15.9 vs 5.9, P = 0.0001). Each additional hardship experienced was associated with an increased average EDr of 7.7 percentage points (R2  = 0.34, P < 0.0001). Housing and utility hardships were each independently associated with increased EDr. CONCLUSION: HMH are associated with significantly increased EDr in children with SCD, independent of transportation hardship or insurance type. Through screening for HMH, providers and health systems could identify at-risk patients with modifiable risk factors for high EDr in order to provide them additional support.

Effective use of hydroxyurea for sickle cell anemia in low-resource countries.

PURPOSE OF REVIEW: Over the past several decades, hydroxyurea has emerged as a well tolerated and potent disease-modifying therapy for children and adults with sickle cell anemia (SCA). Strong, evidence-based recommendations from the National Institutes of Health, American Society of Hematology, and British Society of Haematology document that hydroxyurea is now standard of care treatment for SCA. In low-resource settings, however, hydroxyurea is rarely utilized due to lack of availability, inadequate treatment guidance, and excessive costs. RECENT FINDINGS: Research trials conducted within the Caribbean and sub-Saharan Africa confirm the efficacy of hydroxyurea as a well tolerated, feasible, and beneficial treatment in low-resource countries. Hydroxyurea is therefore vital to reaching the targets for control of SCA outlined by the WHO. To maximize its utilization toward real-world effectiveness, specific attention must be given to healthcare provider education and training, public and institutional awareness, and medication access and affordability. SUMMARY: Efforts to introduce hydroxyurea effectively into low-resource countries should urgently address the lack of treatment guidelines, gaps in knowledge and clinical infrastructure, and medication inaccessibility. Partnerships among governmental, academic, pharmaceutical, and charitable organizations must tackle these barriers so that all individuals living with SCA worldwide can benefit from hydroxyurea.

Universal screening for social determinants of health in pediatric sickle cell disease: A quality-improvement initiative.

BACKGROUND: Social determinants of health (SDoH) are socioeconomic factors that influence health outcomes. Guidelines recommend universal screening for SDoH at clinic visits; however, models that do not require additional resources are limited in subspecialty clinics. Individuals with sickle cell disease (SCD) face the burdens of chronic illness and often racial disparities, both of which may increase their vulnerability to adverse SDoH. Hematologists can impact both quality of life and clinical outcomes for their patients by implementing screening and referral programs addressing SDoH. METHODS: Through prospective, quality-improvement methods, we introduced universal screening for SDoH into our pediatric hematology clinic. The intervention was a paper screener followed by a referral to local community organizations for the specific needs endorsed. The aims of this study were to determine the feasibility of universal screening for SDoH in a busy subspeciality clinic using pre-existing resources to identify the needs of our patients and to facilitate referrals between our patients and community organizations via this low touch intervention. RESULTS: Between August 2017 and November 2018, 156 screens were completed. Sixty-six percent were positive for at least one unmet social need for which 80% were referred to a relevant community organization. Forty-five percent of patients available via follow-up phone call reached out to the community organization. CONCLUSIONS: There is a high burden of SDoH in families of children with SCD. Universal screening at a pediatric hematology clinic with the subsequent connection of patients with SCD to community resources is feasible using existing clinic resources.

Health Equity Rounds: An Interdisciplinary Case Conference to Address Implicit Bias and Structural Racism for Faculty and Trainees.

Introduction: The medical community recognizes the importance of confronting structural racism and implicit bias to address health inequities. Several curricula aimed at teaching trainees about these issues are described in the literature. However, few curricula exist that engage faculty members as learners rather than teachers of these topics or target interdisciplinary audiences. Methods: We developed a longitudinal case conference curriculum called Health Equity Rounds (HER) to discuss and address the impact of structural racism and implicit bias on patient care. The curriculum engaged participants across training levels and disciplines on these topics utilizing case-based discussion, evidence-based exercises, and two relevant conceptual frameworks. It was delivered quarterly as part of a departmental case conference series. We evaluated HER's feasibility and acceptability by tracking conference attendance and administering postconference surveys. We analyzed quantitative survey data using descriptive statistics and qualitatively reviewed free-text comments. Results: We delivered seven 1-hour HER conferences at our institution from June 2016 to June 2018. A mean of 66 participants attended each HER. Most survey respondents (88% or more) indicated that HER promoted personal reflection on implicit bias, and 75% or more indicated that HER would impact their clinical practice. Discussion: HER provided a unique forum for practitioners across training levels to address structural racism and implicit bias. Our aim in dissemination is to provide meaningful tools for others to adapt at their own institutions, recognizing that HER should serve as a component of larger, multifaceted efforts to decrease structural racism and implicit bias in health care.

Delivery of radiation therapy in resource-limited settings: A pilot quality assessment study.

Progress has been made in resource-limited countries in treating acute lymphoblastic leukemia, but advances in solid malignancies have been slower. Multidisciplinary care coordination is challenging, assessing adherence to guidelines through quality improvement initiatives is essential. We characterized deviations from guidelines in the delivery of radiation in a middle-income country program as a pilot for evaluating adequacy of local control and as surrogate for integration of multidisciplinary care. One-third of patients for whom it was indicated did not receive radiation. Of the patients who received radiation, 95% had a deviation. This study underscores the importance of quality assessment in resource-limited settings.

Development of mandibular osteoradionecrosis in rats: Importance of dental extraction.

OBJECTIVES: To develop an animal model of mandibular osteoradionecrosis (ORN) using a high-energy radiation source (as used in human therapeutics) and to assess the role of tooth extraction on ORN development. MATERIALS AND METHODS (STUDY DESIGN): Ten animals were irradiated with a single 35- or 50-Gy dose. Three weeks later, the second left mandibular molar was extracted from three animals in each group. Nine weeks after irradiation, the animals were euthanized, with an injection of contrast agent in the bloodstream to highlight vascularization. Mandibles were harvested and studied using micro-CT, histology, tartrate-resistant acid phosphatase activity and scanning electron microscopy. RESULTS: This study demonstrates that a single 50-Gy dose associated with molar extraction is necessary for ORN development. In these conditions, absence of healing of the mucosa and bone, dental effects, fibrosis, an increase in osteoclast activity and a decrease in vascularization were observed. We also determined that molar extraction increases the impact of the cellular effects of radiation. CONCLUSION: The mandibular ORN animal model was validated after 50-Gy irradiation and molar extraction. The results of this study therefore support an animal ORN model and tissue engineering strategies will now be developed to regenerate bone for patients with head and neck cancer.