Vaso-occlusive Crisis Research Articles

Promising role of Voxelotor in managing sickle cell disease in children: a narrative review.

Sickle cell disease (SCD) is characterized by chronic hemolytic anemia and intermittent vaso-occlusive crises. To date, four disease-modifying drugs have been approved for the treatment of SCD: hydroxyurea (an S-phase inhibitor), L-glutamine (an amino acid), crizanlizumab (a P-selectin inhibitor), and voxelotor (a hemoglobin S polymerization inhibitor). Preclinical studies suggested that voxelotor effectively treats SCD and sickle cell anemia (SCA). In a phase III trial, voxelotor-treated patients showed significantly elevated hemoglobin levels (>1 g/dL from baseline) compared to placebo-treated patients. The group that received voxelotor also showed a greater decrease in hemolytic markers but a comparable incidence of side effects. Six ongoing clinical trials also sought to ascertain the effectiveness and safety of high-dose voxelotor when administered to children younger than 12 years. Studies assessing their long-term efficacy and safety are needed to fully understand the role of voxelotor in treating SCD/SCA. In this review, we discuss the mechanisms, trials to date, and future treatment directions of voxelotor.

Managing emotional and physical stress in sickle cell anemia: a review of effective strategies and approaches

Sickle cell anemia (SCA) is a genetic blood disorder characterized by recurrent pain episodes, chronic complications, and significant emotional and physical stress. This review article explores effective strategies for managing both the emotional and physical aspects of stress in SCA patients. A comprehensive literature search was conducted across multiple databases, including PubMed, Scopus, and Google Scholar, using keywords such as “sickle cell anemia,” “stress management,” “psychological support,” and “pain management.” Emotional stress in SCA arises from chronic pain, frequent hospitalizations, and disease uncertainty, leading to conditions such as anxiety and depression. Effective management of emotional stress involves a combination of psychological counseling, cognitive-behavioral therapy (CBT), and support groups, which help patients develop coping strategies and address the mental health challenges of living with a chronic illness. This review evaluates various psychological interventions and their impact on patient outcomes, emphasizing the need for integrated mental health support in the management of SCA. Physical stress in SCA is primarily due to acute vaso-occlusive crises and chronic pain, which require effective pain management and preventive measures. The review explores pharmacological treatments, such as opioids and hydroxyurea, as well as non-pharmacological approaches, including physical therapy and lifestyle modifications. Additionally, the article discusses innovative therapies like gene therapy and stem cell transplantation, which hold promise for long-term disease management.

Determination of the Level of von Willebrand Factor, ADAMTS13, and Ratio of ADAMTS13:von Willebrand Factor in Sickle Cell Disease Patients.

Sickle cell anemia (SCA) is a hypercoagulable state characterized by a significant alteration in hemostatic parameters which may predispose an increased risk of vaso-occlusive crisis (VOC). Sickle cell disease (SCD) is the most common genetic disorder in sub-Saharan Africa. Nigeria bears a high disease burden with an estimated prevalence of 1%-3% of its population being affected by the disease. The study seeks to determine the role of von Willebrand factor (VWF), ADAMTS13, and the ratio of ADAMTS13:VWF antigen in the pathogenesis of VOC. The objective of this study is to evaluate the level of VWF, ADAMTS13, and their ratio in SCD subjects in Calabar and to determine their role in the pathogenesis of VOC. This is a comparative study carried out at the University of Calabar Teaching Hospital (UCTH), Calabar. Sixty SCA patients were evaluated in VOC and steady states as well as five parented healthy controls. VWF: Ag and ADAMTS13:Ag were evaluated using Assaypro enzyme-linked immunosorbent assay kits with Lot nos. 01751728 and 04222167R, respectively. Data were analyzed by IBM SPSS Chicago software version 21. The study was approved by the UCTH Institution Ethical Review Board. The mean ages of the SCA subjects and controls were 23.5 ± 7.2 years and 26.5 ± 5.6 years, respectively (P = 0.706). There were 23 (38.3%) males in the SCA group and 21 (42.0%) females in the controls. There was no significant difference in their sex distribution (P = 0.063). The mean (standard deviation [SD]) of VWF in VOC, steady state, and controls were 2.52 ± 0.34, 1.34 ± 0.23, and 1.41 ± 0.23 IU/mL, respectively. The differences in mean were significantly higher in VOC state (P = 0.003). The mean ± SD of ADAMTS13 in VOC, steady state, and controls were 0.61 ± 0.10, 0.44 ± 0.06, and 0.62 ± 0.10 μg/L, respectively. ADAMTS13 levels did not differ significantly across the groups (P = 0.270). Similarly, there was no significant difference between ADAMTS13:VWF ratios across the groups (P = 0.318). VWF level is elevated in VOC state and thus may be implicated in the pathogenesis of VOC. ADAMTS13 and the ratio of ADAMTS13:VWF are not significantly affected in VOC.

Biomarkers to Differentiate Acute Chest Syndrome From Vaso-Occlusive Crisis in Children With Sickle Cell Disease.

Acute Chest Syndrome (ACS) is the leading cause of death in children with sickle cell disease (SCD) in the US-about half of the children who develop ACS present initially with pain. Here, we studied biomarkers to differentiate ACS from vaso-occlusive crises (VOC) in children with SCD who presented with pain to the emergency department (ED). We conducted a prospective cohort study of consecutive patients who presented to the ED with pain and were discharged with ACS or VOC between March, 2017 and February, 2020. We identified 7 patients with ACS and 19 patients with VOC. The two groups were comparable in age and sex. All patients with ACS had asthma versus 42% of the VOC group. The ACS group had lower weight and BMI z-scores. Patients with ACS compared to VOC had significantly higher respiratory rates, lower O2 saturation, and longer hospital stays. They also had higher white blood cell count, glucose level (> 99 mg/dL), anion gap (> 9 mEq/L), sPLA2 (> 7 pg/mL), IFN-γ (> 17.8 pg/mL), IL-10 (1.54 pg/mL), and IL-12 (> 0.5 pg/mL) levels. We identified biomarkers associated with ACS development in children with SCD presenting with pain that allow for earlier ACS interventions to reduce mortality and morbidity.

A Novel One-Sample Mendelian Randomization Approach for Count-Type Outcomes That Is Robust to Correlated and Uncorrelated Pleiotropic Effects.

We propose two novel one-sample Mendelian randomization (MR) approaches to causal inference from count-type health outcomes, tailored to both equidispersion and overdispersion conditions. Selecting valid single-nucleotide polymorphisms (SNPs) as instrumental variables (IVs) poses a key challenge for MR approaches, as it requires meeting the necessary IV assumptions. To bolster the proposed approaches by addressing violations of IV assumptions, we incorporate a process for removing invalid SNPs that violate the assumptions. In simulations, our proposed approaches demonstrate robustness to the violations, delivering valid estimates, and interpretable type-I errors and statistical power. This increases the practical applicability of the models. We applied the proposed approaches to evaluate the causal effect of fetal hemoglobin (HbF) on the vaso-occlusive crisis and acute chest syndrome (ACS) events in patients with sickle cell disease (SCD) and revealed the causal relation between HbF and ACS events in these patients. We also developed a user-friendly Shiny web application to facilitate researchers' exploration of causal relations.

Sickle cell disease in India: Not just a mild condition.

Sickle cell disease (SCD) is a common and life-threatening global health problem, with more than 500 000 affected infants born annually. The burden of SCD in sub-Saharan Africa is well established, but the comparably high prevalence in India is not well recognized and many consider SCD in India to be less severe. In their paper, a national study in India demonstrated the significant impact of SCD for patients, families and the healthcare system, supporting a call to action to recognize and address SCD as a serious and common health condition in India. Commentary on: Seth etal. Burden of vaso-occlusive crisis, its management, and impact on quality of life of Indian sickle cell disease patients. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19829.

Clinical Burden and Health Care Resource Utilization Associated With Managing Sickle Cell Disease With Recurrent Vaso-occlusive Crises in England

PurposeSickle cell disease (SCD) is an inherited red blood cell disease caused by a mutation in the gene encoding the β-subunit of adult hemoglobin that leads to hemolysis, anemia, vaso-occlusive crises (VOCs), morbidity, and mortality. This study provides a real-world assessment of the clinical burden and health care resource utilization (HCRU) associated with SCD with recurrent VOCs in England. MethodsThis retrospective study linked primary care records from the Clinical Practice Research Datalink database with secondary care records from the Hospital Episode Statistics database to identify patients with SCD with recurrent VOCs between July 1, 2008, and June 30, 2018. A VOC was defined as SCD with crisis, acute chest syndrome, or priapism. Eligible patients had SCD, ≥2 VOCs/year in any 2 consecutive years after a diagnosis of SCD, and ≥1 year of follow-up data from the index date. Patients were exact matched with 5 controls from the general population in the databases. Demographics were assessed at index. Mortality, clinical complications, and HCRU were summarized during follow-up. FindingsAfter applying eligibility criteria, 1117 patients with SCD with recurrent VOCs and 5585 controls were included in the study. Mean age at index was 25 years in both groups. The proportion of deaths (3.67% vs 0.68%; P < 0.001) and mortality rate (0.78 deaths per 100 person-years vs 0.16 deaths per 100 person-years) were substantially higher in patients with SCD with recurrent VOCs versus matched controls. Mean (standard deviation [SD]) age of death in patients with SCD with recurrent VOCs who died during the follow-up period was 40.17 (14.09) years. The mean (SD) rate of VOCs for patients with SCD with recurrent VOCs was 5.84 (12.50) per patient per year (PPPY) during follow-up. Compared with matched controls, patients with SCD with recurrent VOCs had substantially higher mean [SD] rates PPPY of inpatient hospitalizations (7.59 [14.50] vs 0.32 [2.71]), prescriptions (31.06 [60.62] vs 7.58 [27.77]), and outpatient visits (9.60 [10.69] vs 1.78 [4.18]). Older patients and those with increased numbers of VOCs had increased mortality, frequency of clinical complications, and HCRU. ImplicationsDespite currently available care, patients with SCD with recurrent VOCs in England have increased mortality, substantial clinical complications, and significant HCRU driven by VOCs and hospitalizations. Elevated mortality and clinical complications in patients with SCD with recurrent VOCs highlight the need for novel therapies in this space.

Morbidité et mortalité en anesthésie pour arthroplastie totale de la hanche sur terrain de drépanocytose dans un pays à faible revenu : cas du centre hospitalier Monkole

Background: Anaesthesia for hip arthroplasty in patients with sickle cell disease is considered a high-risk procedure. This study investigated morbidity and mortality in a low-income country using Monkole Hospital as an example.Methods. A cross-sectional study of electrophoretically confirmed sickle cell patients anaesthetised at Monkole for hip arthroplasty during the period October 2018 to April 2024. Peri-anaesthetic data up to hospital discharge were collected prospectively and analysed with SPSS 26.0 for p<0.05. Anaesthetic management at Monkole is multidisciplinary. Transfusion exchange, Hb S assay, and systematic cardiorespiratory investigations are not performed. Simple transfusion was carried out with the aim of achieving a haemoglobin level of 7 and 9 g/dl.Results. Eighty-six patients were enrolled. The mean age was 26.02 years, 88.54% were aged 18 and over, and 66.3% were women. BMI was <18.5 kg/mm2 in 48.8%; 84.9% were polytransfused; only 9.3% were on hydroxyurea and only one had received exchange transfusion; 2.3% were icteric and 97.7% were classified ASA III. The mean Hb level was 8.3g/dl, and less than 7g/dL in 15.1% of cases. Antibiotic prophylaxis was administered in all patients with cefazolin ± gentamycin. Spinal anaesthesia (bupivacaine + morphine) was used alone (95.3%), combined with general anaesthesia (3.48%), and the prosthesis was cemented in 95.35% of cases. Intraoperative complications were: arterial hypotension (18.6%), discomfort (4.6%), the effect of cementing (4.6%), poor quality of spinal block (1.6%), haemorrhage (2.3%). Transfusion was required for 79.1% of patients intraoperatively and 3.2% postoperatively. Postoperative complications accounted for 11.6%: anaemia (5.8%), vaso-occlusive crisis (2.3%), urinary retention (2.3%), and vomiting (1.6%). No deaths or acute chest syndrome were recorded. All patients spent one day in intensive care and the average hospital stay was 5 days. Alcohol consumption and procedures lasting longer than two hours were associated with intraoperative complications. Leanness, previous anaesthesia, platelet count below 1500000/mm3, prolonged activated partial thromboplastin time, and the presence of intraoperative complications were associated with postoperative complications.Conclusion. There was no and morbidity was represented by minor complications. It seems possible to anaesthetise patients with sickle cell disease for hip arthroplasty without measuring haemoglobin S or exchanging transfusions, with a lower risk of morbidity and mortality.

Effect of ABO Mismatch and RBC Alloimmunization on the Outcome of Hematopoietic Cell Transplantation for Sickle Cell Disease

BackgroundHematopoietic cell transplantation (HCT) remains the only well-established curative option for sickle cell disease (SCD) patients. Nonmyeloablative (NMA) conditioning has been used to improve the outcomes and reduce toxicities in adult SCD patients. However, Recipient/Donor (R/D) ABO incompatibility and alloimmunization could be significant impediments to successful outcomes when transplanting SCD patients due to risks of hemolysis, delayed engraftment, poor graft function and graft failure (GF). Herein, we report our experience with allogeneic HSCT for SCD and the effects of RBC groups mismatch and alloimmunization on the outcome of transplanted patients. MethodsWe conducted a retrospective analysis of all SCD patients (age >14 year) that underwent HSCT from January 2015 to February 2022 at our center. All patients received Intravenous alemtuzumab (1 mg/kg divided over 5 days on days -7 to -3) and 300 cGy TBI on day -2 or -1 for conditioning. Pre-transplant preparation consisted of hydroxyurea at maximum tolerated dose for 2-3 months and one session of exchange transfusion. Peripherally mobilized CD34 stem cells targeting 10 × 106 /kg of recipient weight were used. For graft versus host disease (GVHD) prophylaxis sirolimus was started on day -1 and continued for one year with tapering if lymphoid chimerism was > 50%. For Patients with major ABO incompatibility, we administered 2 doses of rituximab (375 mg/m2) and 3 sessions of plasmapheresis before starting the conditioning regimen targeting an isoheamagglutinin titer < 1/32. The primary objective was to determine the impact of RBC groups mismatch and alloimmunization on the outcome of transplanted patients. The secondary objective was to assess the impact of GF on overall survival (OS). Logistic regression was done to evaluate predictors for GF. Kaplan-Meier method was used for survival analysis. ResultsA total of 194 patients were included with a median age of 26 years. The median baseline Hgb and HbS were 93 g/L and 71.3%, respectively. Indications of stem cell transplantations were most commonly due to recurrent vaso-occlusive crisis in 52.5% of patients, CNS events in 19.6%, and acute chest syndrome in 17%. After a median follow up of 28.8 months (5-83), sixteen patients (8%) experienced graft failure (3 with primary GF and 13 with secondary GF). On univariate analysis, ABO minor incompatibility and RBC alloantibodies against donor non-ABO antigens were predictive for GF.On multivariate analysis RBC alloantibodies against donor non-ABO antigens (OR, 8.29; 95% CI, 2.01 to 34.05, P=0.0033) was the only factor predictive of GF. None of the 16 patients with major ABO incompatibility developed GF. Two-years OS for all patients was 95%. The 2 years OS for patients without GF was 98% compared to 74% in patients with GF, (P<0.0001). ConclusionIn our SCD transplanted patients, RBC alloantibodies against donor non- ABO antigens were an independent risk factor for GF. Patients with GF had an inferior survival and strategies for decreasing GF risk are needed.

Real-World Evidence of Crizanlizumab Showing Reductions in Vaso-Occlusive Crises and Opioid Usage in Sickle Cell Disease.

Access to crizanlizumab, a disease-modifying therapy for sickle cell disease (SCD), was provided through a managed access program (MAP, NCT03720626). The present analysis evaluated the impact of 12 months of crizanlizumab treatment on vaso-occlusive crises (VOCs), and on the use of opioids for VOC-related pain relief, in patients with SCD from the MAP. From June 2018 to January 2023, 112 patients with a history of recurrent VOCs completed 12 months of crizanlizumab (5 mg/kg) treatment and were monitored for adverse events (AEs). Crizanlizumab led to reductions of 18.0% and 36.2% in the proportions of patients having ≥ 1 home- and ≥ 1 healthcare-managed VOCs. Median absolute changes (interquartile range) from baseline in the rates of home- and healthcare-managed VOCs were -3.0 (-6.0, -1.0) and -2.0 (-4.0, 0), respectively. Data stratified by genotype and prior hydroxyurea use showed similar reductions in VOC rates. A 35.5% reduction in the proportion of patients requiring opioids was noted. AEs were consistent with earlier reports, and no new safety concerns were identified. Crizanlizumab demonstrated potential benefits in attenuating VOC episodes, irrespective of SCD genotype and prior hydroxyurea use, and in lowering opioid usage. The safety of crizanlizumab was consistent with earlier reports. The MAP has been registered at ClinicalTrials.gov with the ID, NCT03720626.

Quality of Life and Out-of-Pocket Expenditures for Sickle Cell Disease Patients in Saudi Arabia: A Single-Center Study.

Background: Sickle cell anemia (SCD) is a relatively uncommon health condition in many countries, but it is prevalent in Saudi Arabia mainly due to the high incidence of consanguineous marriages. Regrettably, there are elevated rates of vaso-occlusive crises (VOCs) and blood transfusions, leading to poor quality of life and significant financial strain. Objective(s): This study aimed to assess the frequency of blood transfusions, out-of-pocket expenditures (OOPEs), and health-related quality of life (HRQoL) in SCD patients. Methods: This was a questionnaire-based cross-sectional study that involved SCD patients at a university-affiliated tertiary care center in Riyadh, Saudi Arabia. The patients' medical and sociodemographic characteristics were obtained from the electronic medical records. Data on HRQoL and OOPEs were collected through a questionnaire-based interview. To present the baseline characteristics, descriptive statistics such as mean, standard deviation, frequency, and percentage were used. In addition, various statistical tests, including the Chi-Square test, Student t-test, one-way ANOVA, and multiple linear regression, were performed. Results: One hundred and eighteen patients consented to participate and were included in the analysis. Almost 53% of the patients were females. The mean age of the sample was 31 years, while the age-adjusted quality-adjusted life years (QALYs) was 24.33 years (p-value < 0.0001). Most patients (83.05%) reside in Riyadh with a monthly family income of less than USD 2666.67 (75.42%). Monthly OOPEs were, on average, USD 650.69 ± 1853.96, and one-third of the adult patients reported income loss due to illness, further exacerbating their financial strain. High frequency of blood transfusion (β = -0.0564, p-value = 0.0066) and higher number of comorbidities (β = -0.10367, p-value = 0.0244) were negatively associated with the HRQoL among adult patients. On the other hand, adult patients with higher levels of education had better HRQoL (β = 0.05378, p-value = 0.0377). Conclusions: The findings of this study highlight the negative impact of SCD on patients' HRQoL and financial well-being. This underscores the urgent need for comprehensive systemic approaches to address the challenges posed by SCD in Saudi Arabia.

Mortality, Clinical Complications, and Healthcare Resource Utilization Associated with Managing Transfusion-Dependent β-Thalassemia and Sickle Cell Disease with Recurrent Vaso-occlusive Crises in Italy.

To examine the clinical burden and healthcare resource utilization (HCRU) among patients with transfusion-dependent β-thalassemia (TDT) and patients with sickle cell disease (SCD) with recurrent vaso-occlusive crises (VOCs) in Italy. Eligible patients were identified from an administrative claims database from 1 January 2010 and 1 February 2019. Patients with TDT had ≥ 1 iron chelation treatment, ≥ 8 red blood cell transfusions (RBCTs) during any 12-month period, and ≥ 12 months of available data pre- and post-index (i.e., first RBCT claim). Patients with SCD with recurrent VOCs had ≥ 2 VOCs/year in ≥ 2 consecutive years and ≥ 12 months of available data pre- and post-index (second VOC claim in the second of 2 consecutive years). Patients were propensity score matched to five controls by age, sex, geographic area, and index year. Clinical and HCRU outcomes were evaluated post-index. In total, 214 patients with TDT and 111 patients with SCD with recurrent VOCs were matched to 1070 and 555 controls, respectively. Both patient groups had substantially higher mortality rates than controls (TDT: 4.8 versus 0.8 deaths per 100 person-years; SCD: 1.6 versus 0.4 deaths per 100 person-years). Clinical complications were prevalent in both patient groups. Compared with controls, both patient groups had significantly higher mean rates of all-cause hospitalizations (TDT: 1.4 versus 0.1; SCD: 2.0 versus 0.1) and outpatient services (TDT: 21.9 versus 1.6; SCD: 6.2 versus 1.0) per patient per year (all: p < 0.05). Management of TDT and SCD in Italy is associated with significant clinical and health system burden, highlighting the need for new treatments that eliminate RBCTs and VOCs.

Beat-to-beat analysis of hemodynamic response to mental and psychological stress in sickle cell anemia

Abstract Vaso-occlusive crises are a hallmark symptom of sickle cell disease. Physical stressors can trigger decreased microvascular blood flow and increase the risk for vaso-occlusive crises. However, the effect of mental and psychological stressors on vascular physiology in sickle cell disease is not well-established. We hereby examined fluctuations in continuous blood pressure to evaluate hemodynamic changes in sickle cell disease patients during mental and psychological stress. Thirteen sickle cell disease subjects from the Children’s Hospital Los Angeles and 11 healthy volunteers were recruited. Continuous blood pressure was recorded during two mental tasks and one psychological stress task. Systolic beat-to-beat blood pressure variability measurements were calculated for each subject. Three very short-term blood pressure variability metrics served as outcome measures: standard deviation, coefficient of variation, and average real variability. Peripheral augmentation index was calculated from arterial waveforms. Linear mixed effects models evaluated associations between patient factors and outcome measures. Sickle cell disease patients exhibit increased systolic blood pressure variability in response to psychological stress. All subjects exhibited a decrease in systolic blood pressure variability in response to mental stress tasks. During mental stress, both groups displayed increased augmentation index, reflective of stress-induced vasoconstriction, while psychological stress in sickle cell disease patients led to both decreased mean arterial pressure and increased augementation index, suggestive of uncompensated vasoconstriction. These findings emphasize the impact of mental and psychological stressors on vascular function in sickle cell disease and the potential for monitoring physiological signals to predict vaso-occlusive crisis events.

Burden of vaso-occlusive crisis, its management and impact on quality of life of Indian sickle cell disease patients.

Sickle cell disease (SCD) with vaso-occlusive pain crisis (VOC) significantly impacts patient well-being and often results in extensive healthcare resource utilization. This study assessed the VOC burden, its management and its impact on patients' quality of life (QoL). A cross-sectional observational study was conducted between November 2021 and June 2022, including 1000 SCD patients from high-prevalence states in India. Data on demographics, clinical characteristics, VOC severity, management and QoL were collected. The study revealed that 33.5% of patients reported at least one VOC episode during the study period. In the year prior to their enrolment, 836 (83.60%) patients reported at least one VOC episode, with an equal proportion of 407/487 (83.6%) adults and 429/513 (83.6%) paediatric patients, reducing their QoL across all domains compared to patients without VOC. Of these, 469/1000 patients (46.9%) experienced ≥3 VOC episodes. Additionally, 764/1000 (76.40%) patients managed their VOCs at healthcare facilities, with 501/1000 (50.1%) requiring inpatient admissions. Further, 71.80% of patients received Hydroxyurea (HU) therapy. The study depicts the severity of the Arab-Indian haplotype in Indian SCD patients visiting healthcare settings based on high VOC burden. This highlights the urgent need for better management strategies and resource allocation for these patients.

Sickle Cell Anemia and Pregnancy Hemolysis: Clinical Considerations

Sickle cell anemia (SCA) is a hereditary blood disorder characterized by abnormal hemoglobin production, leading to chronic hemolysis and episodic vaso-occlusive crises (VOCs). Pregnancy in women with SCA poses significant clinical challenges due to the increased physiological demands, which exacerbate hemolysis and increase maternal and fetal risks. This review explores the pathophysiology of hemolysis in SCA during pregnancy, its clinical implications, and management strategies aimed at improving maternal and fetal outcomes. Hemolysis can result in severe anemia, acute chest syndrome, increased risk of infections, and adverse fetal outcomes, such as intrauterine growth restriction and preterm delivery. Management strategies for hemolysis in pregnancy include blood transfusions, pharmacological therapies, nutritional supplementation, and emerging treatments like gene therapy. Blood transfusions are widely used to mitigate anemia and reduce the number of circulating sickled cells, while pharmacological agents such as L-glutamine help address oxidative stress. Nutritional support, particularly with folic acid and antioxidants, is essential in promoting healthy red blood cell production and mitigating oxidative damage. Emerging therapies like gene editing offer promising future directions for more effective management of SCA and pregnancy-related hemolysis.

The Current Role of Hydroxyurea in the Treatment of Sickle Cell Anemia.

Despite advancements in treatment of sickle cell disease (SCD), hydroxyurea, a ribonucleotide reductase inhibitor, remains the cornerstone of therapy. While its primary effect is the elevation of fetal hemoglobin (HbF), hydroxyurea's mechanisms of action are multifaceted. Hydroxyurea (HU) reduces leukocyte and platelet counts, decreases the expression of endothelial adhesion molecules CD36 and CD49d, and increases nitric oxide and cyclic nucleotide levels, which may facilitate vascular dilation and further HbF induction. Numerous studies have demonstrated that hydroxyurea therapy reduces the frequency of painful episodes, acute chest syndrome, and the need for erythrocyte transfusions and hospitalizations. Long-term use of hydroxyurea leads to reduced morbidity and mortality. Hydroxyurea should be initiated in children from 9 months of age, including asymptomatic individuals, and is recommended for adults experiencing pain crises that significantly interfere with daily activities or quality of life, as well as those with severe or recurrent vaso-occlusive crises, ACS, or severe symptomatic anemia. Hydroxyurea is not recommended during pregnancy or lactation due to potential teratogenic effects and transfer into breast milk. However, its use may be considered in high-risk patients, particularly during the second and third trimesters. Concerns about secondary tumor development have not been substantiated in long-term follow-up studies. Alternative therapies, including L-glutamine, crizanlizumab, and voxelotor, are not presently approved or available for clinical use in Europe.

Clinical burden and healthcare resource utilization associated with managing sickle cell disease with recurrent vaso-occlusive crises in France

Objective This retrospective, real-world claims database analysis described the clinical burden and healthcare resource utilization (HCRU) among patients with sickle cell disease (SCD) with recurrent vaso-occlusive crises (VOCs) in France. Methods The French National Health Data System database (système national des données de santé) was used to identify eligible patients from January 1, 2012, to March 1, 2019. Inclusion criteria were a SCD diagnosis, ≥2 VOCs/year for ≥2 consecutive years following the diagnosis, and ≥1 year of follow-up data to March 1, 2020. Patients with hereditary persistence of fetal hemoglobin or hematopoietic stem cell transplant in their medical records were excluded. Clinical complications, mortality, treatment use, and HCRU were evaluated during follow-up. Results Overall, 4602 patients with SCD with recurrent VOCs were eligible; their mean (standard deviation [SD]) age was 19.8 (13.5) years, and 51.8% were female. Patients experienced a mean (SD) of 3.82 (3.57) VOCs per patient per year (PPPY). Prevalent complications were anemia or leukocytosis (44.1%), infections (42.0%), and organ failure (38.2%). In total, 101 (2.2%) patients died during follow-up (mean age of death [SD]: 39.3 [17.5] years; mortality rate: 0.64 deaths per 100 person-years). Most patients received opioids (89.1%) and hydroxycarbamide (72.8%). Patients had a mean of 5.7 inpatient hospitalizations, 6.0 emergency room visits, 6.6 outpatient visits, and 13.4 outpatient prescriptions PPPY. Conclusions Patients with SCD with recurrent VOCs in France have substantial clinical complications, mortality, and HCRU despite currently available treatment options. Innovative treatments that reduce frequency of or eliminate VOCs are needed to alleviate the burden associated with SCD.

Management of acute pain in adults with sickle cell disease: the experience of the Clinical Hematology Department of the University of Dakar.

The evolution of sickle cell disease (SCD) is marked by the occurrence of painful episodes linked to the obstruction of microvessels by sickle cells, known as vaso-occlusive crisis (VOC). The aim of this work was to report the practical aspects of the management of acute pain in adults with SCD. Recommendations based on these practices are also provided. This prospective, cross-sectional, descriptive, and analytical study was conducted over a four-month period of all sickle cell patients admitted to emergency departments for VOC. The parameters studied were sociodemographic, clinicobiological, therapeutic, and evolutionary. There were 118 cases of VOC identified, representing a prevalence of 78.14% of sickle cell emergencies. The mean age of the patients was 28.41 years. The SS sickle cell phenotype accounted for 86.61% of the cases. Osteoarticular pain was the reason for admission for 88.39% of the patients; it was located in the lower limbs in 39.08% and in the spine in 27.1%. Pain intensity was moderate in 6.25% of the patients, intense in 31.25%, and unbearable in 55.55%. Multimodal analgesia was the most commonly used treatment method, combining those of levels one and two (74.31%) and levels one and three (8.25%). The mean dose of morphine administered was 17.14 mg when morphine alone was prescribed for titration, 13.57 mg when paracetamol and morphine were combined, and 15.83 mg when nefopam and morphine were combined. Clinical outcome was favorable in 68.87% of the cases. Wide variability was observed in the modalities of analgesic treatment of sickle cell VOC. These variations reflect different views on the appropriateness of opioids. This study highlights the efficacy of multimodal analgesia in the management of acute pain in patients with SCD, particularly in regard to morphine sparing. Context-specific recommendations will be needed to harmonize practices.

Hydroxyurea Pharmacokinetic Evaluation in Patients with Sickle Cell Disease

Background: Hydroxyurea (HU), also known as hydroxycarbamide, is an oral ribonucleotide reductase inhibitor. In 1999, the United States Food and Drug Administration (FDA) approved HU for the treatment of sickle cell disease (SCD). Since then, it has become the cornerstone in the management of SCD patients, helping to reduce vaso-occlusive crises, acute chest syndrome, the need for blood transfusions, hospitalizations and mortality. There is considerable variability among individuals in HU pharmacokinetic (Pk) parameters that can influence treatment efficacy and toxicity. The objective of this work is part of a clinical study aimed at investigating HU Pk and determining the optimal sampling time to estimate the Area Under the Curve (AUC) in SCD patients. Methods: HU plasma concentration in 80 patients at various time points (2, 4, 6, 24 h) following a 48-h drug washout was quantified using High-Pressure Liquid Chromatography (HPLC) coupled with an ultraviolet (UV) detection method previously described in the literature and adapted to new conditions with partial modifications. Results: The mean HU administered dose was 19.5 ± 5.1 mg/kg (range: 7.7–37.5 mg/kg). The median AUC quantified in plasma patients was 101.3 mg/L/h (Interquartile Range (IQR): 72.5–355.9) and it was not influenced by the weight-based dose. However, there was a strong positive correlation between AUC and Body Mass Index (BMI) as well as dose per Body Surface Area (BSA). Along with a three-point approach for AUC determination present in the literature, we show results obtained from a four-point sampling strategy, which is more useful and effective for better optimizing dose escalation to the maximum tolerated dose (MTD). Moreover, we observed that most patients achieved the maximum HU plasma concentration two hours after drug administration, regardless of age differences. Conclusions: HU treatment, which represents a milestone in the treatment of SCD due to its ability to reduce disease complications and improve patients’ quality of life, requires careful monitoring to optimize the individual dose for saving potential side effects and/or adverse events.

Zinc finger nuclease-mediated gene editing in hematopoietic stem cells results in reactivation of fetal hemoglobin in sickle cell disease

BIVV003 is a gene-edited autologous cell therapy in clinical development for the potential treatment of sickle cell disease (SCD). Hematopoietic stem cells (HSC) are genetically modified with mRNA encoding zinc finger nucleases (ZFN) that target and disrupt a specific regulatory GATAA motif in the BCL11A erythroid enhancer to reactivate fetal hemoglobin (HbF). We characterized ZFN-edited HSC from healthy donors and donors with SCD. Results of preclinical studies show that ZFN-mediated editing is highly efficient, with enriched biallelic editing and high frequency of on-target indels, producing HSC capable of long-term multilineage engraftment in vivo, and express HbF in erythroid progeny. Interim results from the Phase 1/2 PRECIZN-1 study demonstrated that BIVV003 was well-tolerated in seven participants with SCD, of whom five of the six with more than 3 months of follow-up displayed increased total hemoglobin and HbF, and no severe vaso-occlusive crises. Our data suggest BIVV003 represents a compelling and novel cell therapy for the potential treatment of SCD.