Hydroxyurea for sickle cell anemia: what have we learned and what questions still remain?

The feasibility of pharmacokinetic-based dosing of hydroxyurea for children with sickle cell anaemia in Uganda: Baseline results of the alternative dosing and prevention of transfusions trial

Pharmacokinetic (PK)-guided dosing of hydroxyurea for children with sickle cell anaemia (SCA) could optimize dosing and improve outcomes, but its feasibility has not been demonstrated in low-resource settings where the majority of affected children live. Alternative Dosing And Prevention of Transfusions (ADAPT) is a prospective trial evaluating blood transfusions and the feasibility of determining PK-guided, hydroxyurea maximum tolerated doses (MTD) for children with SCA in Uganda, using portable high-performance liquid chromatography (HPLC) and a novel PK software programme (HdxSim). ADAPT enrolled 106 participants, and 100% completed PK testing. PK-guided doses were generated for 78%, of which 38% were within the protocol-defined range. Accurately, measuring serum hydroxyurea concentrations via HPLC and the potential for hydroxyurea degradation impacted the feasibility. Ensuring that people with SCA globally have access to hydroxyurea is imperative, and improving treatment strategies requires ongoing innovation including PK-guided dosing. ADAPT is registered at ClinicalTrials.gov (NCT05662098).

The feasibility of pharmacokinetic-based dosing of hydroxyurea for children with sickle cell anaemia in Uganda: Baseline results of the alternative dosing and prevention of transfusions trial

Pharmacokinetic (PK)-guided dosing of hydroxyurea for children with sickle cell anaemia (SCA) could optimize dosing and improve outcomes, but its feasibility has not been demonstrated in low-resource settings where the majority of affected children live. Alternative Dosing And Prevention of Transfusions (ADAPT) is a prospective trial evaluating blood transfusions and the feasibility of determining PK-guided, hydroxyurea maximum tolerated doses (MTD) for children with SCA in Uganda, using portable high-performance liquid chromatography (HPLC) and a novel PK software programme (HdxSim). ADAPT enrolled 106 participants, and 100% completed PK testing. PK-guided doses were generated for 78%, of which 38% were within the protocol-defined range. Accurately, measuring serum hydroxyurea concentrations via HPLC and the potential for hydroxyurea degradation impacted the feasibility. Ensuring that people with SCA globally have access to hydroxyurea is imperative, and improving treatment strategies requires ongoing innovation including PK-guided dosing. ADAPT is registered at ClinicalTrials.gov (NCT05662098).

Emergencies in Hematology: Why, When and How I Treat?

Hematological emergencies are critical medical conditions that require immediate attention due to their rapid progression and life-threatening nature. As various examples, hypercalcemia, often associated with cancers such as multiple myeloma, can lead to severe neurological and cardiac dysfunction. Hyperleukocytosis, common in acute myeloid leukemias, increases the risk of leukostasis and multiorgan failure. Sickle cell crisis, a common complication in sickle cell disease, results from vaso-occlusion, leading to acute pain and tissue ischemia. Tumor lysis syndrome, reported in cases of rapid destruction of cancer cells, causes electrolyte imbalances and acute kidney injury. Acute transfusion reactions, fundamental in hematological conditions, can range from mild allergic responses to severe hemolysis and shock, requiring prompt management. Disseminated intravascular coagulation, involving excessive coagulation and bleeding, is commonly triggered by hematological malignancies, common in the first phases of acute promyelocytic leukemia. Recently, in the era of bispecific antibodies and chimeric antigen receptor T cells, cytokine release syndrome is a manifestation that must be recognized and promptly treated. Understanding the pathophysiology, recognizing the clinical manifestations, and ensuring adequate diagnostic strategies and management approaches for each condition are central to early intervention in improving patient outcomes and reducing mortality.

Discovery and Optimization of First-in-Class Molecular Glue Degraders of the WIZ Transcription Factor for Fetal Hemoglobin Induction to Treat Sickle Cell Disease

Sickle cell disease (SCD) is a prevalent, life-threatening condition with few treatment options, attributed to a heritable mutation in β-hemoglobin. Therapeutic induction of fetal hemoglobin (HbF) with small molecules has been pursued as a treatment to ameliorate many disease complications but with limited success. Herein, we report the discovery of 10, a novel, potent, and selective molecular glue degrader of the transcription factor WIZ that robustly induces HbF expression as a potential treatment for SCD. 10 was optimized from a phenotypic screening hit utilizing insights from X-ray crystallography and computational modeling to improve potency, selectivity and in vivo exposure. In an hNBSGW mouse xenograft model, 10 demonstrated robust WIZ degradation and HbF induction. These results highlight the potential of WIZ degraders as a promising therapy for sickle cell disease.

Global profiling of protein complex dynamics with an experimental library of protein interaction markers

Methods to systematically monitor protein complex dynamics are needed. We introduce serial ultrafiltration combined with limited proteolysis-coupled mass spectrometry (FLiP-MS), a structural proteomics workflow that generates a library of peptide markers specific to changes in PPIs by probing differences in protease susceptibility between complex-bound and monomeric forms of proteins. The library includes markers mapping to protein-binding interfaces and markers reporting on structural changes that accompany PPI changes. Integrating the marker library with LiP-MS data allows for global profiling of protein-protein interactions (PPIs) from unfractionated lysates. We apply FLiP-MS to Saccharomyces cerevisiae and probe changes in protein complex dynamics after DNA replication stress, identifying links between Spt-Ada-Gcn5 acetyltransferase activity and the assembly state of several complexes. FLiP-MS enables protein complex dynamics to be probed on any perturbation, proteome-wide, at high throughput, with peptide-level structural resolution and informing on occupancy of binding interfaces, thus providing both global and molecular views of a system under study.

Post-GWAS Validation of Target Genes Associated with HbF and HbA2 Levels

Genome-Wide Association Studies (GWASs) have identified a huge number of variants associated with different traits. However, their validation through in vitro and in vivo studies often lags well behind their identification. For variants associated with traits or diseases of biomedical interest, this gap delays the development of possible therapies. This issue also impacts beta-hemoglobinopathies, such as beta-thalassemia and sickle cell disease (SCD). The definitive cures for these diseases are currently bone marrow transplantation and gene therapy. However, limitations regarding their effective use restrict their worldwide application. Great efforts have been made to identify whether modulators of fetal hemoglobin (HbF) and, to a lesser extent, hemoglobin A2 (HbA2) are possible therapeutic targets. Herein, we performed the post-GWAS in vivo validation of two genes, cyclin D3 (CCND3) and nuclear factor I X (NFIX), previously associated with HbF and HbA2 levels. The absence of Ccnd3 expression in vivo significantly increased g (HbF) and d (HbA2) globin gene expression. Our data suggest that CCND3 is a possible therapeutic target in sickle cell disease. We also confirmed the association of Nfix with γ-globin gene expression and present data suggesting a possible role for Nfix in regulating Kruppel-like transcription factor 1 (Klf1), a master regulator of hemoglobin switching. This study contributes to filling the gap between GWAS variant identification and target validation for beta-hemoglobinopathies.

Pharmacokinetic-Guided Hydroxyurea to Reduce Transfusions in Ugandan Children with Sickle Cell Anemia: Study Design of the Alternative Dosing And Prevention of Transfusions 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 pretreatment 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.

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 pretreatment 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.

Revolutionising healing: Gene Editing's breakthrough against sickle cell disease

Recent advancements in gene editing illuminate new potential therapeutic approaches for Sickle Cell Disease (SCD), a debilitating monogenic disorder caused by a point mutation in the β-globin gene. Despite the availability of several FDA-approved medications for symptomatic relief, allogeneic hematopoietic stem cell transplantation (HSCT) remains the sole curative option, underscoring a persistent need for novel treatments. This review delves into the growing field of gene editing, particularly the extensive research focused on curing haemoglobinopathies like SCD. We examine the use of techniques such as CRISPR-Cas9 and homology-directed repair, base editing, and prime editing to either correct the pathogenic variant into a non-pathogenic or wild-type one or augment fetal haemoglobin (HbF) production. The article elucidates ways to optimize these tools for efficacious gene editing with minimal off-target effects and offers insights into their effective delivery into cells. Furthermore, we explore clinical trials involving alternative SCD treatment strategies, such as LentiGlobin therapy and autologous HSCT, distilling the current findings. This review consolidates vital information for the clinical translation of gene editing for SCD, providing strategic insights for investigators eager to further the development of gene editing for SCD.

Defining curative endpoints for sickle cell disease in the era of gene therapy and gene editing

A growing number of gene therapy- and gene editing-based treatments for patients with sickle cell disease (SCD) are entering clinical trials. These treatments, designed to target the underlying cause of SCD, have the potential to provide functional cures, which until now were possible only through allogeneic hematopoietic stem cell transplant. However, as these novel approaches advance from early- to late-stage clinical trials, it is essential to identify physiologically and clinically relevant endpoints that can demonstrate the achievement of a functional cure for SCD. Here, we present an overview of the pathophysiology of SCD and current treatment options, review ongoing SCD clinical trials using gene therapy or gene editing approaches, and identify the most relevant endpoints for demonstrating the attainment of a functional cure for SCD.

Predictors of Intensive Care Admission Among Adult Patients with Sickle Cell Disease in Eastern Province of Saudi Arabia

Purpose

Sickle cell disease (SCD) comprises a complex group of hematologic disorders that are collectively the most common monogenic disorder and are associated with increased risk of intensive care unit admission (ICU). The purpose of this study is to investigate factors that predict admission of adult patients with SCD to the ICU.

Patients and Methods

This was a cross-sectional study that enrolled adult patients with SCD from Saudi Arabia.

Results

A total of 107 patients with SCD, with a median age 31.9±12.1 years, were evaluated retrospectively. Regarding predictors of ICU admission, patients who indicated a history of blood transfusions were at 8.047-fold higher risk of ICU admission (OR=8.047; 95% CI=2.392-27.07; p=0.001). Patients who started hydroxyurea were at least 3.071 times more likely to be admitted than those who did not (OR=3.071; 95% CI=1.164-8.104; p=0.023). We also observed three or more hospitalizations per year to be associated with increased risk of ICU admission (OR=3.393; 95% CI=1.285-8.960; p=0.014), with those making 3 to 5 visits annually having at least 10.4 times higher risk (OR=10.38; 95% CI=10.098-98.19; p=0.041) and those with 6 to 10 ER admissions having 18 times higher risk (OR=18.00; 95% CI=2.149-150.8; p=0.008). Finally, patients with high WBC were predicted to have at least 3.34 times higher risk of ICU admission (OR=3.337; 95% CI=1.131-9.846; p=0.029).

Conclusion

SCD is a multi-systemic disease associated with increased morbidity and mortality. Recognition of high-risk features in patients helps to eliminate subjectivity in ICU referral decision. Frequent hospitalization and emergency visits, multiple blood transfusions, and elevated white blood cell count were significantly associated with a higher rate of ICU admission despite hydroxyurea usage.

Impact of Sickle Cell Disease on Academic Performance: A Cross Sectional Study

Purpose

Sickle cell disease (SCD) is a multisystemic disease that results in diverse clinical manifestations in the form of acute and chronic complications. This study aims to assess the academic achievements of patients with SCD.

Methods and Materials

A cross-sectional study was a study conducted among adult patients with SCD from the eastern province of Saudi Arabia, where SCD is more widespread than in other regions.

Results

A total of ninety patients with SCD, whose median age was 32.33 ± 11.84, were retrospectively evaluated. Of the total number, 32 (35.5%) did not obtain a secondary higher education certificate, and five (3.3%) were illiterate. Sixty-three (70%) of the patients were female, indicating no significant association between gender and education level (p-value > 0.05). The patients' mean annual hospitalizations and emergency visits totaling 4.7 and 8.43, respectively, were not significantly associated with education (p-value > 0.05). Throughout the patients' lives, mean blood transfusions and ICU admissions occurred 6.29 and 2.75 times, respectively, which were not significantly associated with education level (p-value > 0.05). However, education was inversely proportional to a history of splenectomy and cholecystectomy (p < 0.05). Laboratory parameters (hemoglobin level, WBC, platelets, and hemoglobin F) showed no significant associations with education level (p-value > 0.05). Patients with sickle-thalassemia exhibited a trend of being better-educated than those without the diseases, but the difference did not reach statistical significance (p-value > 0.05). A linear regression analysis revealed no significant associations among clinical and laboratory parameters.

Conclusion

SCD is a multisystemic disease that impacts socioeconomic status, learning ability, and academic achievements. More research is needed to identify factors that predict poor performance. Additionally, intelligence quotient (IQ) and cognitive assessment should be incorporated into early screening programs for SCD in order to implement preventive measures and a thorough investigation of underlying causes.

Hydroxyurea treatment for adult sickle cell anemia patients in Kinshasa

Background: Despite a high incidence of sickle cell anemia, hydroxyurea (HU) treatment is rarely used in the DR Congo. This study aims to assess the efficacy of HU, the incidence of side effects that may limit its use in adults and to determine the dose needed for clinical improvement in patients. Methods: In a prospective study, patients received an initial dose of 15 mg/kg/day which was increased by 5 mg/kg every 6 months, up to a maximum of 30 mg/kg/day. The response and side effects to HU were evaluated biologically and clinically every 3 months during a 2-year period. Results: Seventy adult patients with a moderate or severe clinical phenotype initiated treatment. Only minor side effects were reported. At the end of the 2-year treatment phase, 45 (64.3%) had dropped out, of whom 33 were without a clear reason. Clinical and biological improvement was more marked during the first year. There was a reduction in severe vaso-occlusive crises (p < 0.001), need for transfusion (p < 0.001), and hospitalization days (p = 0.038). Fetal hemoglobin (HbF) levels increased on average 2.9 times after 12 months (p < 0.001). The increase in mean corpuscular volume was greater in the first year (p < 0.001) than in the second year (p = 0.041). The decrease in leukocytes (p < 0.001) was significant during the first year. In 70% of patients, the 20 mg/kg/day dose was needed to reach the 20% HbF threshold. Conclusion: HU is effective and well tolerated. The magnitude of the response varies from one patient to another. Improvement of clinical manifestations is achieved in most patients with a relatively low dose. Effective implementation of HU treatment will require improved adherence to treatment.

Genotypic and Phenotypic Composition of Sickle Cell Disease in the Arab Population - A Systematic Review

Sickle cell disease (SCD) is a genetic disease influenced by ethnicity and regional differences in its clinical course. Recent advances in the management of SCD with newer therapies are being introduced to the Western population. However, many of these treatments are yet to be used in the Arabic SCD population. Understanding the genetic variations of SCD regionally is essential to anticipate the utilization of new treatments. This systematic review's main objective is to pool the available data on the genetic composition of SCD in the Arabic population. Data for 44,034 patients was extracted from 184 studies (11 case reports, 8 case series, 56 retrospectives, 107 prospective observational studies, and 2 clinical trials) using PubMed, Scopus, and Google Scholar. Male (49%) and female (51%) patients were equally reported wherever gender was available (N=13105). Various SCD genotypes were reported in a total of 14,257 patients, including Hb SS (77%) Hb Sβ0 (9.9%), and Hb Sβ+ (7.2%), while the rest of the genotypes, including HbSC, HbSD, HbSE, HbSO Arab, Hb S/α-Thal, Hb Sβ0 + α-Thal, and HBS Oman were individually reported in <4% of the cases. Major SCD complications in the Arab population included pain crises (48.25%) followed by neurological complications (33.46%), hepatobiliary complications (25.53%), musculoskeletal complications (24.73%), and hemolytic anemia (23.57%). The treatments reported for SCD included hydroxyurea (20%), blood transfusion (14.32%), and Deferasirox (3.03%). We did not find the use of stem cell transplantation or newer treatments such as L-Glutamine, Voxelotor, Crizanlizumab, or gene therapy reported in any of the studies included in our review. This review highlights the genetic makeup of SCD in Arab countries and its common phenotypic manifestations and will help direct further research on SCD in this region, especially concerning genetic therapy.

SYSTEMATIC REVIEW REGISTRATION

The protocol has been registered in the International Prospective Register of Systematic Reviews(PROSPERO):CRD42020218,666. https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=218666.

Antioxidant-Rich Nutraceutical as a Therapeutic Strategy for Sickle Cell Disease

Sickle cell disease (SCD) is a genetically inherited disease in which the "SS" individual possesses two copies of the abnormal beta-globin gene. This disease is one of the most dominant genetic diseases in the world. SCD is marked by the propensity of red cell hemoglobin to polymerize and distort the red cell from a biconcave disk shape into a sickle shape, resulting in a typical vaso-occlusive episode and accelerated hemolysis. Plants are rich sources of bioactive compounds that are promising anti-sickling agents to scavenge free radicals, thereby ensuring oxidative balance. The current review highlights the potential therapeutic benefits of antioxidant-rich nutraceutical in the treatment and management of sickle cell disease. The anti-sickling potential of nutraceutical is attributed to the presence of antioxidant bioactive chemicals such as alkaloids, polyphenols, vitamins, and minerals, which acts as scavengers of free radicals that prevent oxidative damage of the hemoglobin and prevent hemolysis, facilitating longer erythrocyte lifespan. The challenges of current therapies for SCD and future directions are also discussed.KEY TEACHING POINTSSickle cell disease is a genetically inherited disease in which SS individuals possess two copies of the abnormal beta-globin gene.Oxidative stress contributes to the pathophysiology of secondary dysfunction in sickle cell patients.Antioxidants can play a vital role in maintaining a balance between oxidant and antioxidant defense systems.Nutraceutical rich in antioxidants such as alkaloids, polyphenols, vitamins, and minerals is potential therapeutic agents for sickle cell disease.An antioxidant-rich nutraceutical may act to reduce vaso-occlusive crises.

Targeting the Hematopoietic Stem Cell Niche in β-Thalassemia and Sickle Cell Disease

In the last decade, research on pathophysiology and therapeutic solutions for β-thalassemia (BThal) and sickle cell disease (SCD) has been mostly focused on the primary erythroid defect, thus neglecting the study of hematopoietic stem cells (HSCs) and bone marrow (BM) microenvironment. The quality and engraftment of HSCs depend on the BM microenvironment, influencing the outcome of HSC transplantation (HSCT) both in allogeneic and in autologous gene therapy settings. In BThal and SCD, the consequences of severe anemia alter erythropoiesis and cause chronic stress in different organs, including the BM. Here, we discuss the recent findings that highlighted multiple alterations of the BM niche in BThal and SCD. We point out the importance of improving our understanding of HSC biology, the status of the BM niche, and their functional crosstalk in these disorders towards the novel concept of combined therapies by not only targeting the genetic defect, but also key players of the HSC–niche interaction in order to improve the clinical outcomes of transplantation.

Outcome of Hydroxyurea Use in SCD and Evaluation of Patients’ Perception and Experience in Nigeria

Introduction: Hydroxyurea (HU) has been shown to be beneficial in the management of sickle cell disease (SCD) as it improves treatment outcomes. However, despite the benefits of HU, its uptake among SCD patients in Nigeria remains low.

Objective: This study aimed to assess the perception and experience of patients with SCD in Nigeria who are using or had used HU, thereby informing and promoting its use.

Methodology: A multi-centre, cross-sectional study was conducted among 378 SCD patients aged 1–53 years who have enrolled on Sickle Pan African Research Consortium (SPARCO) registry as HU users. The SPARCO project was funded by the National Institutes of Health (NIH) to establish a sickle cell disease (SCD) registry, strengthen skills and plan research in three African countries. The Nigerian SPARCO registry had 6453 SCD patients at the time of this report with <15% of this population on HU. Data on sociodemographics, perception and experience about HU use were obtained and analysed using descriptive statistics.

Findings: Out of the 378 participants, 339 (89.7%) were using HU while 39 (10.3%) had stopped using HU at the time of the study. 281 (74.3%) found HU expensive, while 194 (51.3%) reported none to minimal side effects while using HU. Among patients that stopped HU, cost (59%) and availability (51.3%) were the commonest reasons for discontinuing the drug. Furthermore, 347 (92.5%) had fewer pain crises, 173 (84.8%) had a fewer need for blood transfusion, 145 (86.3%) had improved PCV and 318 (84.6%) had fewer hospital admissions. Finally, the study also showed that 322 (85.2%) respondents would recommend the drug to other patients, whereas 14 respondents (3.7%) would not. Mean corpuscular volume (MCV) and fetal hemoglobin (HbF) levels were not collected in this study and may have improved findings.

Conclusion: This study showed that the majority of the SCD patients had good perception and experience with the use of HU while a few had to stop the medication mostly on account of cost and availability. Patients’ based advocacy could be leveraged to improve HU uptake while more efforts are needed to ensure that it is readily available and affordable.

Addressing Severe Chronic NCDs Across Africa: Measuring Demand for the Package of Essential Noncommunicable Disease Interventions-Plus (PEN-Plus)

Severe chronic non-communicable diseases (NCDs) pose important challenges for health systems across Africa. This study explores the current availability of and demand for decentralization of services for four high-priority conditions: insulin-dependent diabetes, heart failure, sickle cell disease, and chronic pain. Ministry of Health NCD Programme Managers from across Africa (N = 47) were invited to participate in an online survey. Respondents were asked to report the status of clinical care across the health system. A care package including diagnostics and treatment was described for each condition. Respondents were asked whether the described services are currently available at primary, secondary and tertiary levels, and whether making the service generally available at that level is expected to be a priority in the coming 5 years. Thirty-seven (79%) countries responded. Countries reported widespread gaps in service availability at all levels. We found that just under half (49%) of respondents report that services for insulin-dependent diabetes are generally available at the secondary level (district hospital); 32% report the same for heart failure, 27% for chronic pain and 14% for sickle cell disease. Reported gaps are smaller at tertiary level (referral hospital) and larger at primary care level (health centres). Respondents report ambitious plans to introduce and decentralize these services in the coming 5 years. Respondents from 32 countries (86%) hope to make all services available at tertiary hospitals, and 21 countries (57%) expect to make all services available at secondary facilities. These priorities align with the Package of Essential NCD Interventions-Plus. Efforts will require strengthened infrastructure and supply chains, capacity building for staff and new monitoring and evaluation systems for efficient implementation. Many countries will need targeted financial assistance in order to realize these goals. Nearly all (36/37) respondents request technical assistance to organize services for severe chronic NCDs.

Hydroxyurea usage awareness among patients with sickle-cell disease in Saudi Arabia

BACKGROUND AND AIM

Hydroxyurea (HU) plays an essential role in the complex pathophysiology alteration of sickle-cell disease (SCD), which translates clinically into the enhanced quality of life and increased survival. This research examines adult patients with SCD's attitudes and awareness toward HU, as well as underutilization consequences.

METHOD

A cross-sectional research was performed in Saudi Arabia, and adult patients with SCD were interviewed. The survey includes patient demographics, attitudes, and knowledge of HU and clinical data. The chi-square was applied through SPSS version 23 for assessing any association with outcome variables and demographic characteristics.

RESULTS

HU is known to 72 (67.3%) of the 107 patients. The hydroxyurea treatment was initiated in 46 patients (63%). Of these, 23 (50%) discontinue HU, with the key factors being pregnancy preparation and side effects development. For those who were unaware of HU, 13 (37.1%) were admitted to the intensive care unit because of acute chest syndrome, 29 (82.8%) required a frequent blood transfusion and 12 (34.2%) with frequent hospitalizations. However, there was no significant relationship between awareness and education level (P value is .078 > .05). In addition, there was no significant relationship between the level of awareness and age and gender of participants (P value is .68 and .44, respectively).

CONCLUSION

HU is a long-established and effective disease-modifying agent for SCD patients, but it is underutilized. The causality of underuse is bidirectional between patients and healthcare providers. It is essential to educate healthcare providers and patients with SCD about hydroxyurea role in modifying disease severity, resolving adverse events, and achieving full benefits.

How I approach disease-modifying therapy in children with sickle cell disease in an era of novel therapies

Finally,after decades of stagnation, the therapeutic landscape for sickle cell disease (SCD) is changing with an increasing number of novel therapeutics. Hydroxyurea remains the primary disease-modifying therapy and, when started early in life with maintenance of an optimal dose, can reduce many SCD-related complications. To complement hydroxyurea, there are a growing number of pharmacologic options with additional efforts focused on the development and optimization of curative therapies. Here, we review current treatment options and provide recommendations as to how to approach the treatment of children and adolescents within this evolving therapeutic landscape to allow for full and healthy lives.

Acute Chest Syndrome in Sickle Cell Disease: Clinical Presentation and Outcomes. The Experience of a Single Thalassemia and Sickle Cell Unit in a University Hospital

Acute chest syndrome (ACS) is a common cause of death for sickle cell disease patients. This syndrome is defined as: respiratory symptoms, new X-ray findings developed and/or fever; ACS requires prompt treatment to avoid clinical deterioration and death in adults with sickle cell disease. Sixteen episodes of acute chest syndrome were studied in 16 adults with sickle cell disease. The clinical and radiological findings, treatment, response and outcome of the episode were evaluated respectively. The patient's past history and comorbidities were taken into account in the outcome and days of hospitalization. Fourteen patients recovered with no sequelae; one patient who required mechanical ventilation also recovered; one patient died due to pulmonary emboli. The mean hospitalization days were 7.43.

Total Annual Economic Burden of Patients with Sickle Cell Disease in Steady State in Greece

Sickle cell disease includes a group of congenital hemolytic anemias, all characterized by the predominance of Hb S (HBB: c.20A>T). The population movement due to economic migration or escape from conflict zones will further affect the health systems of countries by either increasing the number of patients or forcing countries to create care units for sickle cell disease patients. This will probably also increase the incidence of the disease in areas where their incidence and prevalence were previously low. In the present study, an attempt has been made to estimate the total annual cost of the treatment of sickle cell disease in Greece. This was the first attempt to calculate the total annual cost of treating sickle cell disease patients in a steady state. The annual cost of sickle cell disease was estimated to be €21,152,340.00 (US$25,219,300.41), without calculating the cost of hospitalization for severe complications. Since 2013, in Greece, a pharmaceutical expenditure limit (decreasing with the years) has been budgeted at €1,945,000,000.00 (US$2,318,965,150.00), annually. It is therefore calculated that approximately 1.0% of the budget allocated to pharmaceutical spending is used to treat patients with sickle cell disease.

ADAMTS-13-VWF axis in sickle cell disease patients

Sickle cell disease (SCD) comprises a group of genetic disorders characterized by the presence of the hemoglobin (Hb) S in homozygosis or in heterozygosis with some other Hb variant or in interaction with thalassemia. SCD is characterized by a very complex pathophysiology, which determines a wide variability of clinical manifestations, including a chronic state of hypercoagulability responsible for the increased risk of thromboembolic events. ADAMTS13 and von Willebrand factor (VWF) play an important role in arterial and venous thrombosis. Thus, the aim of this study was to understand how the ADAMTS13-VWF axis behaves in sickle cell disease, as well as whether there is an association of these markers with the use of hydroxyurea (HU). This is a cross-sectional study conducted with 40 patients diagnosed with SCD and 40 healthy individuals. The analysis of the ADAMTS13-VWF axis was comparatively performed between groups of patients and controls and, afterwards, between patients with SCD who were users and non-users of HU. ADAMTS13 activity, ADAMTS13 activity/VWF:Ag, and ADAMTS13:Ag/VWF:Ag ratios were significantly lower and VWF:Ag levels significantly higher in SCD patients when compared to the controls. There was no statistically significant difference in ADAMTS13:Ag and VWF collagen binding (VWF:CB) levels between the groups evaluated. Among the categories of HU use, there was no statistically significant difference in any of the evaluated markers. As a conclusion, we could observe that the ADAMTS13-VWF axis is altered in SCD when compared to healthy individuals and that there is no association between these markers and the use of HU.

Hydroxyurea Optimization through Precision Study (HOPS): study protocol for a randomized, multicenter trial in children with sickle cell anemia

Background

Sickle cell disease (SCD) is a severe and devastating hematological disorder that affects over 100,000 persons in the USA and millions worldwide. Hydroxyurea is the primary disease-modifying therapy for the SCD, with proven benefits to reduce both short-term and long-term complications. Despite the well-described inter-patient variability in pharmacokinetics (PK), pharmacodynamics, and optimal dose, hydroxyurea is traditionally initiated at a weight-based dose with a subsequent conservative dose escalation strategy to avoid myelosuppression. Because the dose escalation process is time consuming and requires frequent laboratory checks, many providers default to a fixed dose, resulting in inadequate hydroxyurea exposure and suboptimal benefits for many patients. Results from a single-center trial of individualized, PK-guided dosing of hydroxyurea for children with SCD suggest that individualized dosing achieves the optimal dose more rapidly and provides superior clinical and laboratory benefits than traditional dosing strategies. However, it is not clear whether these results were due to individualized dosing, the young age that hydroxyurea treatment was initiated in the study, or both. The Hydroxyurea Optimization through Precision Study (HOPS) aims to validate the feasibility and benefits of this PK-guided dosing approach in a multi-center trial.

Methods

HOPS is a randomized, multicenter trial comparing standard vs. PK-guided dosing for children with SCD as they initiate hydroxyurea therapy. Participants (ages 6 months through 21 years), recruited from 11 pediatric sickle cell centers across the USA, are randomized to receive hydroxyurea either using a starting dose of 20 mg/kg/day (Standard Arm) or a PK-guided dose (Alternative Arm). PK data will be collected using a novel sparse microsampling approach requiring only 10 μL of blood collected at 3 time-points over 3 h. A protocol-guided strategy more aggressive protocols is then used to guide dose escalations and reductions in both arms following initiation of hydroxyurea. The primary endpoint is the mean %HbF after 6 months of hydroxyurea.

Discussion

HOPS will answer important questions about the clinical feasibility, benefits, and safety of PK-guided dosing of hydroxyurea for children with SCD with potential to change the treatment paradigm from a standard weight-based approach to one that safely and effectively optimize the laboratory and clinical response.

Trial registration

ClinicalTrials.gov NCT03789591. Registered on 28 December 2018.

Thrombin generation in vivo and ex vivo in sickle cell disease patients

Activation of coagulation is an important hallmark of sickle cell disease (SCD) and it is believed that hypercoagulability plays a role to the disease pathophysiology. Studies have sought to identify how hemostatic biomarkers are expressed in SCD, however, the results are inconclusive. In this context, our objective was to evaluate the thrombin generation in vivo and ex vivo in SCD patients and the association between these biomarkers and the use of HU. This cross-sectional study was carried out with patients diagnosed with SCD, users or not of Hydroxyurea (HU), and healthy individuals as controls. D dimer (D-Di) was evaluated by ELISA and (TGT) thrombin generation test by CAT method. D-Di plasma levels were significantly higher in SCD patients when compared to the controls. TGT parameters such as peak, ETP and normalized ETP at low TF concentration and time-to-peak, peak, ETP and normalized ETP values at high TF concentration were lower in SCD patients than in controls. In contrast, the normalized activated protein C sensitivity ratio (nAPCsr) was higher in patients compared to controls, indicating resistance to the action of this natural anticoagulant. Regarding the use of HU, comparing users and non-users of this drug, no difference was observed in D-Di levels and in most TGT parameters. Our data analyzed together allow us to conclude that patients with SCD present a state of hypercoagulability in vivo due to the higher levels of D-Di and resistance to APC assessed ex vivo which is consistent with the coagulation imbalance described in SCD patients.

Timing of Alemtuzumab With Respect to Day of Bone Marrow Infusion and its Effects Upon Engraftment and Graft-Versus-Host Disease in Patients With Sickle Cell Disease: A Single-Institutional Study

The possible impact of "late" alemtuzumab (administered on days -10 to -8) versus "early" alemtuzumab (-19 to -17) with respect to engraftment and acute/chronic graft-versus-host disease (GvHD) in a group of 25 pediatric patients with sickle cell disease undergoing bone marrow transplantation following conditioning with alemtuzumab, fludarabine, and melphalan is reported. The first 9 patients received "late" alemtuzumab followed by bone marrow transplantation from HLA-matched sibling donors. The next 16 patients undergoing matched sibling transplants received "early" alemtuzumab. In the "late" group, 1 patient (11%) developed acute GvHD. Six patients (67%) achieved sustained engraftment. Three patients (33%) experienced graft rejection, leading to termination of enrollment of patients on this regimen. In the "early" alemtuzumab group, acute and chronic GvHD developed in 43% and 25% patients, respectively. None of the patients experienced graft rejection in this group of patients. Three patients developed stable mixed chimerism and 13 patients demonstrated 100% donor chimerism at 1 year post-transplant and beyond. These results suggest a benefit with respect to engraftment of administering "early" versus "late" alemtuzumab in this reduced-intensity conditioning regimen, however, with the possible cost of an increase in acute, and possibly chronic GvHD.

Changing the Clinical Paradigm of Hydroxyurea Treatment for Sickle Cell Anemia Through Precision Medicine

Sickle cell anemia (SCA) is a common and devastating inherited blood disorder, affecting millions of people across the world. Without treatment, SCA results in tremendous morbidity and early mortality. Hydroxyurea is the primary and most well-established pharmacologic therapy with proven benefits to ameliorate the clinical course of SCA, primarily due to its ability to increase the expression of fetal hemoglobin (HbF), which prevents sickling of red blood cells. The optimal induction of HbF depends upon selection and maintenance of the proper dose that maximizes benefits and minimizes toxicity. Due to the significant interpatient variability in hydroxyurea pharmacokinetics, pharmacodynamics, and dosing, most patients treated with hydroxyurea receive suboptimal doses and have only modest treatment responses. Recognizing this variability, using a precision medicine approach, we developed and prospectively evaluated an individualized dosing model for children with SCA, designed to optimize the hydroxyurea dose and clinical response. We utilize novel laboratory methods and a sparse sampling strategy requiring only 10 μL of blood collected 15 minutes, 60 minutes, and 180 minutes after a test dose. We use Bayesian adaptive control to estimate hydroxyurea exposure and to select an individual, optimal starting dose. This dosing model has resulted in HbF responses >30-40%, levels beyond what is achieved with traditional weight-based dosing and trial and error dose escalation. This hydroxyurea dosing strategy, if widely implemented, has the potential to change the treatment paradigm of hydroxyurea therapy and improve outcomes for the millions of patients with SCA across the world.

Phytomedicines (medicines derived from plants) for sickle cell disease

BACKGROUND

Sickle cell disease, a common recessively inherited haemoglobin disorder, affects people from sub-Saharan Africa, the Middle East, Mediterranean basin, Indian subcontinent, Caribbean and South America. It is associated with complications and a reduced life expectancy. Phytomedicines (medicine derived from plants in their original state) encompass many of the plant remedies from traditional healers which the populations most affected would encounter. Laboratory research and limited clinical trials have suggested positive effects of phytomedicines both in vivo and in vitro. However, there has been little systematic appraisal of their benefits. This is an updated version of a previously published Cochrane Review.

OBJECTIVES

To assess the benefits and risks of phytomedicines in people with sickle cell disease of all types, of any age, in any setting.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register, the International Standard Randomised Controlled Trial Number Register (ISRCTN), the Allied and Complimentary Medicine Database (AMED), ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). Dates of most recent searches: Cochrane Cystic Fibrosis and Genetic Disorders Haemoglobinopathies Trials Register: 17 March 2020; ISRCTN: 19 April 2020; AMED: 18 May 2020; ClinicalTrials.gov: 24 April 2020; and the WHO ICTRP: 27 July 2017.

SELECTION CRITERIA

Randomised or quasi-randomised trials with participants of all ages with sickle cell disease, in all settings, comparing the administration of phytomedicines, by any mode to placebo or conventional treatment, including blood transfusion and hydroxyurea.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed trial quality and extracted data.

MAIN RESULTS

Three trials (212 participants) of three phytomedicines: Niprisan® (also known as Nicosan®), Ciklavit® and a powdered extract of Pfaffia paniculata were included. The Phase IIB (pivotal) trial suggests that Niprisan® may be effective in reducing episodes of severe painful sickle cell disease crisis over a six-month period (low-quality evidence). It did not appear to affect the risk of severe complications or the level of anaemia (low-quality evidence). The single trial of Cajanus cajan (Ciklavit®) reported a possible benefit to individuals with painful crises, and a possible adverse effect (non-significant) on the level of anaemia (low-quality evidence). We are uncertain of the effect of Pfaffia paniculata on the laboratory parameters and symptoms of SCD (very low-quality of evidence). No adverse effects were reported with Niprisan® and Pfaffia paniculata (low- to very low-quality evidence).

AUTHORS' CONCLUSIONS

While Niprisan® appeared to be safe and effective in reducing severe painful crises over a six-month follow-up period, further trials are required to assess its role in managing people with SCD and the results of its multicentre trials are awaited. Currently, no conclusions can be made regarding the efficacy of Ciklavit® and the powdered root extract of Pfaffia paniculata in managing SCD. Based on the published results for Niprisan® and in view of the limitations in data collection and analysis of the three trials, phytomedicines may have a potential beneficial effect in reducing painful crises in SCD. This needs to be further validated in future trials. More trials with improved study design and data collection are required on the safety and efficacy of phytomedicines used in managing SCD.

Design, synthesis, and optimization of a series of 2-azaspiro[3.3]heptane derivatives as orally bioavailable fetal hemoglobin inducers

Pharmacological reactivation of the γ-globin gene for the production of fetal hemoglobin (HbF) is a promising approach for the management of β-thalassemia and sickle cell disease (SCD). We conducted a phenotypic screen in human erythroid progenitor cells to identify molecules that could induce HbF, which resulted in identification of the hit compound 1. Exploration of structure-activity relationships and optimization of ADME properties led to 2-azaspiro[3.3]heptane derivative 18, which is more rigid and has a unique structure. In vivo using cynomolgus monkeys, compound 18 induced a significant dose-dependent increase in globin switching, with developable properties. Moreover, compound 18 showed no genotoxic effects and was much safer than hydroxyurea. These findings could facilitate the development of effective new therapies for the treatment of β-hemoglobinopathies, including SCD.

Drug Therapies for the Management of Sickle Cell Disease

Sickle cell disease (SCD) afflicts millions of people worldwide but is referred to as an orphan disease in the United States. Over the past several decades, there has been an increasing understanding of the pathophysiology of SCD and its complications. While most individuals with SCD in resource-rich countries survive into adulthood, the life expectancy of patients with SCD remains substantially shorter than for the general African-American population. SCD can be cured using hematopoietic stem cell transplantation and possibly gene therapy, but these treatment approaches are not available to most patients, the majority of whom reside in low- and middle-income countries. Until relatively recently, only one drug, hydroxyurea, was approved by the US Food and Drug Administration to ameliorate disease severity. Multiple other drugs (L-glutamine, crizanlizumab, and voxelotor) have recently been approved for the treatment of SCD, with several others at various stages of clinical testing. The availability of multiple agents to treat SCD raises questions related to the choice of appropriate drug therapy, combination of multiple agents, and affordability of recently approved products. The enthusiasm for new drug development provides opportunities to involve patients in low- and middle-income nations in the testing of potentially disease-modifying therapies and has the potential to contribute to capacity building in these environments. Demonstration that these agents, alone or in combination, can prevent or decrease end-organ damage would provide additional evidence for the role of drug therapies in improving outcomes in SCD.

Immune mechanisms involved in sickle cell disease pathogenesis: current knowledge and perspectives

Sickle cell disease (SCD) is caused by a single point mutation in the β-chain of the hemoglobin gene that results in the replacement of glutamic acid with valine in the hemoglobin protein. However, recent studies have demonstrated that alterations in several other genes, especially immune related genes, may be associated with complications of SCD. In fact, higher chronic inflammatory status is related to more severe clinical symptoms in SCD patients, suggesting crucial roles of the immune system in SCD physiopathology. Nevertheless, although participation of innate immune cells in SCD pathogenesis has been broadly and extensively described, little is known about the roles of the adaptive immune system in this disease. In addition, the influence of treatments on the immune system of SCD patients and their complications (such as alloimmunization) are not yet completely understood. Thus, we reviewed the current knowledge about the immune mechanisms involved in SCD pathogenesis. We suggest recommendations for future studies to allow for a broader understanding of SCD pathogenesis, helping in the development of new therapies and improvement in the life quality and expectancy of patients.

Perceived benefits and risks of participation in a clinical trial for Ugandan children with sickle cell anemia

INTRODUCTION

Understanding factors that affect the decisions of caregivers of African children to enroll their children in clinical trials would lead to more fully informed consent.

METHODS

During the NOHARM study (NCT01976416), a placebo-controlled clinical trial of hydroxyurea for Ugandan children with sickle cell anemia (SCA), 206 caregivers were given a semistructured questionnaire about factors that influenced participation in the study and their perceptions of study benefits and risks. Factors were further assessed with focus group discussions.

RESULTS

Caregivers identified education provided during the recruitment process (44%), the child's current poor state of health (35%), and the possibility of improvement in the child's health (16%) as their primary initial reasons for deciding to participate in the NOHARM trial. Concerns regarding the drug or participation in a research study, including the stated concern of death by several caregivers, were outweighed by the possibility of improvement in the child's health. During the study, 72% of caregivers cited improved health as an advantage of study participation, while disadvantages cited included the potential side effects of hydroxyurea, most of which did not occur during the trial.

DISCUSSION

Our study findings highlight the generally poor state of health of Ugandan children with SCA, the desperation by caregivers for anything that could improve the child's health, and the inevitable improvements in care that result from strict adherence to a study protocol, even a protocol based on local guidelines. Studies in this vulnerable population must be careful not to portray improved care as a primary incentive for participation.

The Evolving Pharmacotherapeutic Landscape for the Treatment of Sickle Cell Disease

Sickle cell disease (SCD) is an extremely heterogeneous disease that has been associated with global morbidity and early mortality. More effective and inexpensive therapies are needed. During the last five years, the landscape of the pharmacotherapy of SCD has changed dramatically. Currently, 54 drugs have been used or under consideration to use for the treatment of SCD. These fall into 3 categories: the first category includes the four drugs (Hydroxyurea, L-Glutamine, Crizanlizumab tmca and Voxelotor) that have been approved by the United States Food and Drug Administration (FDA) based on successful clinical trials. The second category includes 22 drugs that failed, discontinued or terminated for now and the third category includes 28 drugs that are actively being considered for the treatment of SCD. Crizanlizumab and Voxelotor are included in the first and third categories because they have been used in more than one trial. New therapies targeting multiple pathways in the complex pathophysiology of SCD have been achieved or are under continued investigation. The emerging trend seems to be the use of multimodal drugs (i.e. drugs that have different mechanisms of action) to treat SCD similar to the use of multiple chemotherapeutic agents to treat cancer.

Ischemia-Reperfusion Injury in Sickle Cell Disease: From Basics to Therapeutics

Sickle cell disease (SCD) is one of the most common hereditary hemoglobinopathies worldwide, affecting almost 400,000 newborns globally each year. It is characterized by chronic hemolytic anemia and endothelial dysfunction, resulting in a constant state of disruption of the vascular system and leading to recurrent episodes of ischemia-reperfusion injury (I/RI) to multiple organ systems. I/RI is a fundamental vascular pathobiological paradigm and contributes to morbidity and mortality in a wide range of conditions, including myocardial infarction, stroke, acute kidney injury, and transplantation. I/RI is characterized by an initial restriction of blood supply to an organ, which can lead to ischemia, followed by the subsequent restoration of perfusion and concomitant reoxygenation. Recent advances in the pathophysiology of SCD have led to an understanding that many of the consequences of this disease can be explained by mechanisms associated with I/RI. The following review focuses on the evolving pathobiology of SCD, how various complications of SCD can be attributed to I/RI, and the role of timely therapeutic intervention(s) based on targeting mediators or pathways that influence I/R insult.

Phenotypic-screening generates active novel fetal globin-inducers that downregulate Bcl11a in a monkey model

Heritable disorders associated with hemoglobin production are the most common monogenic disorders. These are mainly represented by disorders such as β-thalassemia and sickle cell disease. Induction of fetal hemoglobin (HbF) has been known to ameliorate the clinical severity of these β hemoglobinopathies. A high throughput phenotypic screening was used in this study to isolate novel compounds that may enhance the expression of γ-globin, the component of HbF, in human erythroid cell lines and primary erythroid progenitors derived from human CD34⁺ cells. The effect of lead compounds on epigenetic enzymes and key transcriptional factors was evaluated to identify their mode of action. One hit compound was further evaluated in vivo using monkey models. Among the ~18,000 compounds screened, 18 compounds were selected and tested to determine their ability to induce HbF in human erythroid cell lines and primary erythroid cells. One of these compounds, a 3-phenyl-isoxazole derivative, could potentially induce HbF in monkey bone marrow cells when administered orally. The compound downregulated negative transcriptional regulators of HbF, Bcl11a and LRF without inhibiting the known epigenetic enzymes. These studies demonstrated the advantages associated with phenotype-screening and identified novel fetal globin inducers that may be useful for treating hemoglobinopathies.

Hydroxyurea Initiation Among Children With Sickle Cell Anemia

This study assesses characteristics of children with sickle cell anemia associated with hydroxyurea initiation. Medicaid administrative claims from 6 states (2005-2012) were used to identify children with sickle cell anemia enrolled in Medicaid for ≥2 years. Hydroxyurea use was defined as >30 days' supply of filled prescriptions. Children were classified as initiators (no use in year 1; use in year 2) or nonusers (no use in either year). Logistic regression was used to estimate associations between initiation, health care encounters, and demographics. A total of 4435 children were enrolled for 2 years during the study period; 885 (20.0%) initiators and 3080 (69.4%) nonusers. Children had an annual mean of 2.0 sickle cell disease-related inpatient admissions (SD = 2.2), 8.2 sickle cell disease-related outpatient visits (SD = 7.2), and 3.6 emergency department visits (SD = 3.5). The odds of initiating hydroxyurea increased with increasing health care utilization, age, and calendar year (all P values <.05).

HABIT efficacy and sustainability trial, a multi-center randomized controlled trial to improve hydroxyurea adherence in youth with sickle cell disease: a study protocol

Background

Hydroxyurea (HU) is recommended as standard practice for youth with sickle cell disease (SCD). Yet, despite its efficacy, HU adherence in adolescents and young adults is often poor. Poor medication adherence increases disease burden, healthcare cost and widens health disparities. Adolescence is a critical time to improve adherence through improved chronic disease self-management. This study aims to test the efficacy of an intervention delivered to youth/parent dyads by community health workers (CHWs), augmented by tailored text messages on HU adherence (primary outcome). Secondary outcomes are intervention sustainability, youth health-related quality of life, self-management responsibility concordance, acute hospital use and self-reported disease symptoms.

Methods

Hydroxyurea Adherence for Personal Best in Sickle Cell Disease, “HABIT,” is a 12 month multi-center randomized controlled trial. One hundred four youth, 10 to 18 years of age prescribed HU who meet eligibility criteria, enrolled with their parent as dyads, will be randomized 1:1 to either the HABIT intervention or to usual clinical care plus education handouts. All subjects will complete clinic visits at months 0, 2, 4, 6 (efficacy component), 9 and 12 (sustainability component) for assessment of HbF biomarker, other hematologic parameters, and to complete questionnaires. In addition, dyads assigned to the HABIT intervention will work with CHWs to identify a daily habit (e.g., brushing teeth) on which to build a HU adherence habit. Tailored daily text message reminders to support the habit will be developed by the dyad in collaboration with the CHWs and sent to parent and youth. At the 6 month visit, the intervention will end and the sustainability portion of the trial will begin. All data analyses will be based on intention to treat with all randomized subjects included in the analyses.

Discussion

Prior retrospective studies demonstrate that a majority of adolescents are poorly adherent to HU. If efficacious, the HABIT intervention has the potential to improve the lives of youth with SCD.

Trial registration

Clinicaltrials.gov NCT03462511. Registered March 6, 2018, last updated July 26, 2019.

Role of some members of chemokine/cytokine network in the pathogenesis of thalassemia and sickle cell hemoglobinopathies: a mini review

The word of hemoglobinopathy is described for an array of disorders that affecting hemoglobin (Hb) functions. Hb is a molecule with 68 kDa molecular weight, serving as oxygen carrying metalloprotein. Hemoglobinopathy includes a wide range of Hb structural deficits varying from thalassemia to sickle cell disease. Cyto-chemokine network members are pivotally involved in the pathogenesis of hemoglobinopathies, however, the exact role of these mediators in the development of these disorders yet to be well addressed. Cytokines and chemokines are generated by inflamed endothelial cells that promote the expression of their respected receptors and further activate NF-κβ, recruit red blood cells (RBCs) and white blood cells (WBCs) toward the inflamed endothelium. Therefore, due to critical roles played by the cyto-chemokine network in several aspects of hemoglobinopathies pathophysiology including apoptosis of endothelial cells, RBC, WBC and etc.…, in the present review, we focused on the critical parts played by this network in the pathogenesis of hemoglobinopathies.

Barriers to the use of hydroxyurea in the management of sickle cell disease in Nigeria

Hydroxyurea (HU) is a well-known Hb F-inducing agent with proven clinical and laboratory efficacy for patients with sickle cell disease. However, concerns about its long-term safety and toxicity have limited its prescription by physicians and acceptability by patients. Thus, this study aims to evaluate clinician's barriers to the use of HU in the management of patients with sickle cell disease in Nigeria. An online survey targeted physicians in pediatrics, hematology, medicine, family medicine and general medical practice managing sickle cell disease in Nigeria. The survey was in four sections: demographic, knowledge and experience with HU, and barriers to the use of HU. Ninety-one (73.0%) of 123 contacts completed the survey. Seventy-three percent and 74.0% of the respondents noted that HU reduced transfusion rates and improved overall quality of life (QOL) of patients, respectively. While the majority of the practitioners (55.6%) see between 10-50 patients per month, most (66.7%) write <5 prescriptions for HU per month. Lack of a national guideline for use of HU, especially in children (52.0%), concern for infertility (52.0%), and safety profile of HU in pregnancy and lactation (48.2%), top the factors considered by the respondents as major barriers to the use of HU. Hydroxyurea is grossly under prescribed in Nigeria, despite that the vast majority of physicians who attend patients with sickle cell disease know about its clinical efficacy. Evidence-based clinical practice guidelines could be explored as a way to standardize practices and improve confidence of practitioners to improve physicians' prescription of HU in the management of sickle cell disease.

Interventions for treating neuropathic pain in people with sickle cell disease

BACKGROUND

Pain is the hallmark of sickle cell disease (SCD) and it can be severe, frequent and unpredictable. Although nociceptive pain is more common, at times, people with SCD may have neuropathic pain. The latter can occur due to peripheral or central nerve injury. This review is focused on identifying treatment of only painful sensory neuropathy in people with SCD.

OBJECTIVES

To determine the effectiveness and safety of any pharmacological or non-pharmacological therapies for treating neuropathic pain in people with SCD.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched trial registries, the reference lists of relevant articles and reviews and contacted experts in the field.Date of last search: 31 January 2019.

SELECTION CRITERIA

Randomised controlled trials (RCTs) (parallel or cross-over in design), quasi-RCTs of pharmacological or non-pharmacological therapies for treating neuropathic pain in people with SCD compared to placebo or another intervention in any category (i.e. pharmacological or non-pharmacological).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed all trials identified by the searches and extracted relevant data. Two authors independently assessed the risk of bias in the selected trials using the Cochrane risk of bias tool. Two review authors independently rated the quality of the evidence for each outcome using the GRADE guidelines.

MAIN RESULTS

One RCT of 22 participants with SCD, conducted in the USA was included in this review. Participants were randomly assigned to either pregabalin (n = 11) or placebo (n = 11). Oral pregabalin was administered at an initial dose of 75 mg twice daily. The drug was titrated at increments of 75 mg to a maximum of 600 mg daily or decreased by 75 mg per day if necessary, based on clinical presentation and pain level. Neuropathic pain was assessed using self-reports on the Leeds Assessment of Neuropathic Symptoms and Signs (S-LANNS) scale and the Neuropathic Pain Symptom Inventory (NPSI), where higher scores were indicative of more pain. Outcomes included self-reported pain, quality of life and withdrawal due to adverse effects measured at baseline and monthly for three months post-intervention. The overall risk of bias was low with a high risk of bias due to attrition.In relation to this reviews primary outcomes, for self-reported neuropathic pain relief, given the paucity of data, we are very uncertain whether there is a difference between the pregabalin and placebo groups at the end of three months as measured by the S-LANSS scale, mean difference (MD) -2.00 (95% confidence interval (CI) -9.18 to 5.18), or the NPSI scale, MD -11.10 (95% CI -33.97 to 11.77) (very low-quality evidence). There was no report of 'Patient Global Impression of Change' in the included trial.Although the mean quality of life scores (Short Form-36) at three months showed small increases in seven of the eight domains post-intervention in the pregabalin group as compared to the placebo group, this was very low-quality evidence and we are very uncertain whether pregabalin increases quality of life. Neither of our pre-defined outcomes of 'time to improvement of symptoms' or 'changes in sleep quality', were measured in the included trial.While treatment-related adverse effects appeared higher in pregabalin group than the placebo group at three months, this was very low-quality evidence and we are very uncertain whether there is a difference, RR 1.33 (95% CI 0.39 to 4.62) (very low-quality evidence). There was one withdrawal for adverse effects in the pregabalin group while three people withdrew or dropped out from the placebo group due to adverse effects and complications and hospitalisation related to SCD.

AUTHORS' CONCLUSIONS

The included trial provided very low-quality evidence. Self-reported pain relief was greater in the pregabalin group compared to the placebo control group but only using the S-LANSS scale and we are very unsure whether there is a difference. While the pregabalin group tended to have improved quality of life over the duration of the trial, this was very low-quality evidence and we are uncertain whether there is a difference. Adverse effects and withdrawals were similar across the treatment and placebo control group in trial. There are both insufficient trials addressing this review question and insufficient outcomes addressed in the single included RCT. Therefore, there is still a significant gap in evidence on interventions for neuropathic pain in people with SCD.

Hydroxyurea: Pattern of Use, Patient Adherence, and Safety Profile in Patients with Sickle Cell Disease in Oman

OBJECTIVES

Many barriers contribute to the underutilization of hydroxyurea (HU) in the treatment of sickle cell disease (SCD), and adherence to its use is often reported to be suboptimal. It is important to have information on the safety of HU in patients with SCD. Our study assessed the pattern of use, patients' adherence to medication, discontinuation of use, and safety of HU in patients with SCD.

METHODS

This cross-sectional study was conducted in the department of medicine of a referral hospital in Oman over five months and included a review of patient files and patient interview. Approval was obtained from the Regional Research and Ethics Committee of the A'Dakhiliyah Governorate and the hospital administration. The parameters were compared between groups using the chi-square test.

RESULTS

Of 298 patients studied, 128 (43.0%) had used HU at some points. The difference in the prevalence of HU use was statistically significant based only on age (p = 0.014), with younger patients more likely to be currently using HU or used HU in the past. The majority of patients were adherent (82.5%) based on self-reported adherence. The prevalence of discontinuation (temporary or permanent) of HU use was high (57.0%), and suspected adverse drug reaction (ADR) was the most common reason. Among those who had never used HU, 33.7% of patients had an indication for the initiation of HU. A quarter of patients who used HU developed a suspected ADR, with blood abnormalities being the commonest. The duration of HU use influenced ADR prevalence (p = 0.015).

CONCLUSIONS

Among the current users of HU, the majority of the patients were adherent based on self-reported medication adherence. The prevalence of discontinuation of HU use and instances of non-initiation of HU among those indicated were high. A larger study, ideally of a prospective nature, in various governorates of Oman, would provide a wider picture at the national level.

Greater number of perceived barriers to hydroxyurea associated with poorer health-related quality of life in youth with sickle cell disease

BACKGROUND

Despite medical benefits, hydroxyurea adherence in adolescents is often poor. As part of a baseline assessment of 28 youth (10-18 years) parent dyads who participated in a 6-month feasibility trial to improve hydroxyurea adherence, we measured the relationship between greater barriers to adherence and health-related quality of life (HRQL) from youth and parent perspectives.

PROCEDURE

Barriers were measured using the Adolescent and Parent Medication Barriers Scales with nine hydroxyurea items added. Barriers reported by ≥25% of the sample were considered common. Generic and disease-specific HRQL were measured by PedsQL and PedsQL Sickle Cell Disease modules. Data were analyzed using descriptive statistics, Cronbach alpha, Spearman correlation coefficients, and paired t tests.

RESULTS

Fifty-six subjects (28 dyads) participated. Youth reported greater barriers compared with parents (5.0 ± 3.9 and 3.5 ± 3.2; P = 0.03), with >80% of respondents reporting ≥1 barriers. Twelve barriers were reported by ≥25% of adolescents, whereas six were reported by ≥25% of parents. Of these, only two were common to both dyad members. Approximately one-third of youth had generic and disease-specific HRQL scores that fell at or below cutoff scores, suggesting being at risk for impaired HRQL. Greater barriers were inversely associated with poorer generic (parent r = -0.43, P = 0.03; youth r = -0.44, P < 0.001) and disease-specific HRQL (parent r = -0.53, P = 0.005; youth r = -0.53, P < 0.001).

CONCLUSIONS

Hydroxyurea barriers were frequently reported but differed by dyad members' perspective. Greater barriers were associated with poorer generic and disease-specific HRQL. To reduce barriers to hydroxyurea in youth with sickle cell disease, perspectives of both dyad members should be addressed.

Hydroxyurea use among children with sickle cell anemia

This study describes hydroxyurea use among children ages 1 to 17 with sickle cell anemia (SCA) enrolled in at least one year of Medicaid in six states from 2005 to 2012. Administrative claims were used to summarize the number of days' supply of hydroxyurea dispensed by state and year. A total of 7963 children with SCA contributed 22 424 person-years. Among person-years with greater than 30 days of hydroxyurea, only 18% received at least 300 days of hydroxyurea, which varied by state. Following updated recommendations for all children with SCA to be offered hydroxyurea, strategies to increase hydroxyurea adherence among this population are needed.

Analyses of rRNA gene chromatin in cell cycle arrested Saccharomyces cerevisiae cells

The existence of two chromatin structures in the rDNA locus was previously demonstrated for a large variety of organisms, ranging from yeast to human. In yeast there are about 150–200 rRNA genes organized in tandem repeats. Almost half of them are transcribed and largely depleted of nucleosomes (active/open), the other half is not transcribed and is assembled in regular arrays of nucleosomes (inactive/closed). It is proposed that RNA polymerase-I (RNAPI) transcription-elongation removes nucleosomes from closed rRNA genes (opening), and that soon after DNA replication there is deposition of nucleosomes on the open rRNA genes (closing). In G1 arrested cells, nearly all rRNA genes are depleted of nucleosomes, but most of them are not transcribed (inactive/open). In relation to the research article by Charton et al. (Mutat. Res.), the data presented here are on the hydroxyurea concentration-dependent inhibition of yeast culture growth, on cell cycle arrest before completion of genome replication, and on the opening of rRNA gene chromatin. As comparison, data are presented for yeast arrested in the G1-phase of the cell cycle by the pheromone α-factor.

Current challenges in the management of patients with sickle cell disease - A report of the Italian experience

Sickle cell disease (SCD) is an inherited red blood cell disorder caused by a structural abnormality of hemoglobin called sickle hemoglobin (HbS). Clinical manifestations of SCD are mainly characterized by chronic hemolysis and acute vaso-occlusive crisis, which are responsible for severe acute and chronic organ damage. SCD is widespread in sub-Saharan Africa, in the Middle East, Indian subcontinent, and some Mediterranean regions. With voluntary population migrations, people harboring the HbS gene have spread globally. In 2006, the World Health Organization recognized hemoglobinopathies, including SCD, as a global public health problem and urged national health systems worldwide to design and establish programs for the prevention and management of SCD. Herein we describe the historical experience of the network of hemoglobinopathy centers and their approach to SCD in Italy, a country where hemoglobinopathies have a high prevalence and where SCD, associated with different genotypes including ß-thalassemia, is present in the native population.

In yeast cells arrested at the early S-phase by hydroxyurea, rRNA gene promoters and chromatin are poised for transcription while rRNA synthesis is compromised

Hydroxyurea (HU) is an inhibitor of ribonucleotide reductase that is used as a chemotherapeutic agent to treat a number of chronic diseases. Addition of HU to cell cultures causes reduction of the dNTP cellular pool below levels that are required for DNA replication. This trigger dividing cells to arrest in early S-phase of the cell cycle. Cell division hinges on ribosome biogenesis, which is tightly regulated by rRNA synthesis. Remarkably, HU represses the expression of some genes the products of which are required for rRNA maturation. To gain more information on the cellular response to HU, we employed the yeast Saccharomyces cerevisiae as model organism and analyzed the changing aspects of closed to open forms of rRNA gene chromatin during cell cycle arrest, the arrangement of RNA polymerase-I (RNAPI) on the open genes, the presence of RNAPI transcription-factors, transcription and rRNA maturation. The rRNA gene chromatin structure was analyzed by psoralen crosslinking and the distribution of RNAPI was investigated by chromatin endogenous cleavage. In HU arrested cells nearly all rRNA genes were in the open form of chromatin, but only a portion of them was engaged with RNAPI. Analyses by chromatin immuno-precipitation confirmed that the overall formation of transcription pre-initiation complexes remained unchanged, suggesting that the onset of rRNA gene activation was not significantly affected by HU. Moreover, the in vitro transcription run-on assay indicated that RNAPI retained most of its transcription elongation activity. However, in HU treated cells, we found that: (1) RNAPI accumulated next to the 5'-end of rRNA genes; (2) considerably less rRNA filaments were observed in electron micrographs of rDNA transcription units; and (3) rRNA maturation was compromised. It is established that HU inhibition of ribonucleotide reductase holds back DNA replication. This study indicates a hitherto unexplored cellular response to HU, namely altered rRNA synthesis, which could participate to hamper cell division.

Insight into the complex pathophysiology of sickle cell anaemia and possible treatment

Sickle cell anaemia (SCA) is the consequence of abnormal haemoglobin production due to an inherited point mutation in the β-globin gene. The resulting haemoglobin tetramer is poorly soluble when deoxygenated, and when this is prolonged, intracellular gelation of sickle haemoglobin occurs, followed by haemoglobin polymerisation. If many cycles of sickling and unsickling occur, the red cell membrane will be disrupted leading to haemolysis and vaso-occlusive events. Recent studies have also shown that leucocyte adhesion molecules and nitric oxide (NO) depletion are involved in endothelial damage. New insights in SCA pathophysiology and vascular biology have shown that cell-derived microparticle (MP) generation is also involved in the vaso-occlusion. Endothelial damage is perpetuated by impaired production or increased consumption of protective modulators such as protein C, protein S and NO. New therapeutic interventions should address these aspects of SCA pathogenesis. To date, the only US-FDA-approved therapy to prevent painful vaso-occulsive episodes is hydroxyurea that reduces haemoglobin polymerisation in sickle cells by increasing the production of foetal haemoglobin and L-glutamine. However, several new drugs have been tested in the last years in randomised clinical trials. We here report an update on the current status of knowledge on SCA.

Characteristics and outcomes of patients with essential thrombocythemia or polycythemia vera diagnosed before 20 years of age: a systematic review

Although it is well known that myeloproliferative neoplasms occur in younger patients, few large cohorts of such patients have been reported. Thus, our knowledge about circumstances of diagnosis, outcome and treatment is limited, especially for children and young adults. We therefore performed a systematic review of cases, published since 2005, concerning patients aged below 20 years at the time of diagnosis of essential thrombocythemia or polycythemia vera. We identified 396 cases of essential thrombocythemia and 75 of polycythemia vera. The median age at diagnosis was 9.3 and 12 years, respectively, and females constituted 57.6% and 45% of the groups, respectively. Half of the patients were asymptomatic at diagnosis. The proportion of so-called triple negativity was high: 57% in essential thrombocythemia and 73% in polycythemia vera. The incidence of thrombosis during the follow-up was 9.3% in patients with polycythemia vera and less, 3.8%, in those with essential thrombocythemia. Venous events were predominant (84.2%), with hemorrhagic episodes being rarer (<5%). The risk of evolution also seemed low (2% to myelofibrosis and no reports of acute leukemia), but the median follow-up was only 50 months. Survival curves were not available. Half of the patients received an antithrombotic drug and 40.5% received a cytoreductive drug. All data should be analyzed with care because of the proportion of missing data (10.7% to 74.7%). This review highlights interesting points concerning this population of young patients with myeloproliferative neoplasms, including that such patients were identified as negative for all common driver mutations, but also shows the need for larger contemporary cohorts with longer follow-up to assess the true prognosis of these patients.

Effect of crizanlizumab on pain crises in subgroups of patients with sickle cell disease: A SUSTAIN study analysis

The cell adhesion molecule P-selectin plays a key role in the pathogenesis of a vaso-occlusive crisis (VOC) in patients with sickle cell disease (SCD). In the double-blind, placebo-controlled phase 2 SUSTAIN study, crizanlizumab (humanized, anti-P-selectin monoclonal antibody) 5 mg/kg significantly lowered the rate of VOC in patients with SCD by 45% vs placebo. In SUSTAIN, patients with SCD were randomized to crizanlizumab 2.5 mg/kg, crizanlizumab 5 mg/kg, or placebo intravenously 14 times over 52 weeks. The primary endpoint was the annual rate of VOC with crizanlizumab vs placebo. This post hoc descriptive analysis evaluated the proportion of patients who did not experience a VOC during the study in the following subgroups: VOCs in the year prior to study entry (2-4/5-10), SCD genotype (HbSS/non-HbSS), and concomitant hydroxyurea use (yes/no). More patients were VOC event-free in the crizanlizumab 5 mg/kg arm than in the placebo arm, including those with more frequent prior VOCs (ie, 5-10; 28.0% vs 4.2%), the HbSS genotype (31.9% vs 17.0%) and/or using concomitant hydroxyurea (33.3% vs 17.5%). Further analyses of secondary endpoints demonstrated that crizanlizumab treatment significantly increased time-to-first VOC vs placebo in these subgroups. The rates of treatment-emergent adverse events were similar between treatment arms across all subgroups. This post hoc analysis of SUSTAIN shows that in patients with a high number of prior VOCs, on concomitant hydroxyurea and/or with the HbSS genotype, crizanlizumab treatment increases the likelihood of patients being VOC event-free and delays time-to-first VOC.