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Introduction: Sickle cell disease is an inherited disorder characterized by hemoglobin S polymerization leading to vaso-occlusion and hemolytic anemia. These result in a variety of pathological events, causing both acute and chronic complications. Millions around the world are affected by sickle cell disease with predominance in sub-Saharan Africa. Hydroxyurea was the first drug approved for use in sickle cell disease to reduce the occurrence of painful crises and blood transfusions in patients with frequent, moderate to severe painful crises., Areas Covered: With the development of new therapeutics, the role of hydroxyurea is evolving. This narrative review aims to provide clinical data, safety information, and supplementary evidence for the role of hydroxyurea in the current era of sickle cell disease. A comprehensive literature search of databases, including PubMed and Cochrane Library, was conducted from 1963 to 2024., Expert Opinion: Even though new medications have been approved for sickle cell disease, hydroxyurea remains the gold standard. Hydroxyurea is not only a disease modifier but it has additional clinical benefits, it is affordable, and its longevity has prompted expanded research in areas such as underutilization and pharmacogenomics. As the treatment landscape evolves, hydroxyurea's long-standing record of efficacy and safety continues to support its role as a key agent in disease management.

Hydroxyurea treatment for children with sickle cell anemia (SCA) is effective and life-saving. Stepwise escalation to maximum tolerated dose (MTD) provides optimal benefits, but is logistically challenging and time-consuming, especially in low-income countries where most people with SCA live. Model-informed precision dosing (MIPD) of hydroxyurea expedites MTD determination and improves outcomes compared with trial-and-error dose adjustments. HdxSim, a user-friendly, online, clinical decision support tool was developed to facilitate hydroxyurea MIPD and evaluated using real-world pharmacokinetic (PK) data. First-dose hydroxyurea PK profiles were analyzed from two clinical trial datasets (Hydroxyurea Study of Long-Term Effects (HUSTLE), NCT00305175 and Therapeutic Response Evaluation and Adherence Trial (TREAT), NCT02286154). Areas under the concentration-time curve (AUC) estimated by HdxSim were compared with those determined using traditional trapezoidal methodology and PK software (MWPharm-DOS). The doses predicted by HdxSim and MWPharm-DOS were compared with the observed clinical MTD. For HUSTLE participants, HdxSim accurately estimated hydroxyurea AUC compared with the trapezoidal method, with < 20% variance. The average (mean ± SD) AUC for TREAT participants estimated with HdxSim (68.6 ± 18.0 mg*hour/L) was lower than MWPharm-DOS (78.6 ± 20.7 mg*hour/L, P = 0.012), but the average recommended doses were not different (425 vs. 423 mg/day, P = 0.97). Moreover, HdxSim was non-inferior to MWPharm-DOS at predicting clinical MTD (absolute difference 3.9 ± 5.8 vs. 4.9 ± 8.2 mg/kg/day, P = 0.19). HdxSim accurately estimates hydroxyurea exposure and is noninferior to traditional PK approaches at predicting the clinical hydroxyurea MTD. Hydroxyurea dosing based on target exposure leads to improved outcomes in children with SCA, and has the potential to make PK-guided hydroxyurea dosing more accessible to this neglected population globally., (© 2023 The Authors. Clinical Pharmacology & Therapeutics © 2023 American Society for Clinical Pharmacology and Therapeutics.)

Methemoglobinemia secondary to administration of hydroxyurea is only reported in veterinary medicine as a result of accidental ingestion of high doses, and once at therapeutic dose in human medicine. A 2.5-year-old female spayed mixed breed dog was presented for acute signs of neurologic disease and diagnosed with severe erythrocytosis without an identified underlying cause, leading to suspicion of polycythemia vera. The dog was managed with phlebotomies, supportive care, and administration of hydroxyurea. Within 2 h of administration of hydroxyurea (37 mg/kg) administration, respiratory distress with cyanosis, and methemoglobinemia developed. Signs resolved within 24 h but recurred after a second administration of lower dosage of hydroxyurea (17 mg/kg) 20 days later. The dog remained asymptomatic except for mild cyanosis but was humanely euthanized for lack of relevant improvement of signs of neurologic disease. This case report documents the repeated occurrence of methemoglobinemia in a dog after administration of hydroxyurea at therapeutic doses., (© 2024 The Author(s). Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Objective: To delineate the natural history of splenic complications other than loss of splenic function in children with sickle cell disease (SCD), we performed a retrospective chart review of patients with SCD treated at the Texas Children's Hospital., Methods: We determined the dates of diagnoses of splenic complications, the number of acute splenic sequestration crises (ASSC), and hydroxyurea treatment in pediatric patients with SCD. We also examined the association of hydroxyurea therapy with the onset and severity of ASSC., Results: The cumulative prevalence of splenic complications was 24.7% for splenomegaly, 24.2% for ASSC, 9.6% for hypersplenism, and 5.6% for splenectomy. The cumulative prevalence of splenic complications was highest in patients with hemoglobin Sβ 0 (69.2%), intermediate in hemoglobin SS (33.3%), low in hemoglobin SC (9.0%), and non-existent in hemoglobin Sβ + . The overall event rate of ASSC was 8.3 per 100 patient-years. The event-rate was 28.4 for hemoglobin Sβ 0 , 10.9 for hemoglobin SS, and 3.5 for hemoglobin SC. Patients with hemoglobin SS and hemoglobin Sβ 0 on hydroxyurea therapy had a significantly higher occurrence of ASSC than those who were not, with event rates of 14.2 and 3.1, respectively. The event rate was also higher for children who started hydroxyurea before age 2 years than for those who started after this age (19.8 and 9.2, respectively)., Conclusions: The prevalence and severity of splenic problems vary widely between different sickle cell genotypes, with hemoglobin Sβ 0 having the most severe complications. Hydroxyurea therapy is associated with increased incidence of ASSC, particularly when initiated before 2 years of age., (© 2024 Wiley Periodicals LLC.)

Chronic skin ulcers in patients with suspected pyoderma gangrenosum can, on closer inspection and further workup, have a different cause. Recognition of key features on clinical examination such as the presence of atrophie blanche is key to avoid misdiagnosis of pyoderma gangrenosum and its subsequent treatment with high-dose corticosteroids and other immunosuppressive medications.

Background: Evidence supports the benefits of hydroxyurea (HU) in adults with sickle cell disease (SCD), but reservations remain due to long-term concerns of fertility. Retrospective analysis of clinical records of SCD patients (haemoglobin SS genotype) have identified gender-related differences in disease progression. This could inform risk stratification during SCD at diagnosis with the possibility to guide therapeutic decisions., Methods: This systemic review and meta-analysis evaluated fertility parameters in both children (aged ≥ 6 years) and adults with SCD receiving HU therapy. Studies were sourced from PubMed and EMBASE from inception to July 2023. A total of 160 potentially relevant articles were identified., Results: Four studies were included that evaluated the effects of HU on sperm parameters in males. A further 4 studies assessed anti-mullerian hormone (AMH) levels and ovarian reserves in females. Differences from baseline values were used to identify compromised fertility. Amongst males, HU treatment negatively impacted the concentration of spermatozoa (MD = -15.48 million/mL; 95% CI: [-20.69, -10.26]; p< 0.001), which continued following treatment cessation (MD = -20.09 million/mL; 95% CI: [-38.78, -1.40]; P = 0.04). HU treatment also led to lower total sperm counts (MD = -105.87 million; 95% CI: [-140.61, -71.13]; P< 0.001) which persisted after treatment (MD = -53.05 million; 95% CI: [-104.96, -1.14]; P = 0.05). Sperm volume, initial forward motility and morphology were unaffected by HU treatment. In females, HU treatment decreased the mean AMH levels 1.83 (95% CI [1.42, 2.56]. A total of 18.2.% patients treated with HU showed reduced ovarian reserves., Interpretation & Conclusions: This systemic review and meta-analysis suggest that the use of HU for SCD impacts seminal fluid parameters in males and can diminish AMH levels and ovarian reserves in females., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Sewaralthahab et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Realizing Effectiveness Across Continents with Hydroxyurea (REACH) is an open-label non-randomised trial of hydroxyurea (hydroxycarbamide) in children with sickle cell anaemia in sub-Saharan Africa. The short-term results of REACH on safety, feasibility, and effectiveness of hydroxyurea were published previously. In this paper we report results from extended hydroxyurea treatment in the REACH cohort up to 8 years., Methods: In this open-label, non-randomised, phase 1/2 trial, participants were recruited from four clinical sites in Kilifi, Kenya; Mbale, Uganda; Luanda, Angola; and Kinshasa, Democratic Republic of Congo. Eligible children were 1-10 years old with documented haemoglobin SS or haemoglobin Sβ zero thalassaemia, weighing at least 10 kg. Participants received fixed-dose hydroxyurea of 17.5 (±2.5) mg/kg per day for 6 months (fixed-dose phase), followed by 6 months of dose escalation (2·5-5·0 mg/kg increments every 8 weeks) as tolerated, up to 20-35 mg/kg per day (maximum tolerated dose; MTD), defined as mild myelosuppression. After the MTD was reached, hydroxyurea dosing was optimised for each participant on the basis of changes in bodyweight and laboratory values over time (MTD with optimisation phase). After completion of the first 12 months, children with an acceptable toxicity profile and favourable responses were given the opportunity to continue hydroxyurea until the age of 18 years. The safety and feasibility results after 3 years has been reported previously. Here, haematological responses, clinical events, and toxicity rates were compared across the dosing phases (fixed-dose hydroxyurea vs MTD with optimisation phase) as protocol-specified outcomes. REACH is registered on ClinicalTrials.gov (NCT01966731) and is ongoing., Findings: We enrolled 635 children between July 4, 2014, and Nov 11, 2016. 606 children were given hydroxyurea and 522 (86%; 266 [51%] boys and 256 [49%] girls) received treatment for a median of 93 months (IQR 84-97) with 4340 patient-years of treatment. The current (Oct 5, 2023) mean dose is 28·2 (SD 5·2) mg/kg per day with an increased mean haemoglobin concentration (7·3 [SD 1·1] g/dL at baseline to 8·5 [1·5] g/dL) and mean fetal haemoglobin level (10·9% [SD 6·8] to 23·3% [9·5]) and decreased absolute neutrophil count (6·8 [3·0] × 10 9 cells per L to 3·6 [2·2] × 10 9 cells per L). Incidence rate ratios (IRR) comparing MTD with fixed-dose hydroxyurea indicate decreased vaso-occlusive episodes (0·60; 95% CI 0·52-0·70; p<0·0001), acute chest syndrome events (0·21; 0·13-0·33; p<0·0001), recurrent stroke events (0·27; 0·07-1·06; p=0·061), malaria infections (0·58; 0·46-0·72; p<0·0001), non-malarial infections (0·52; 0·46-0·58; p<0·0001), serious adverse events (0·42; 0·27-0·67; p<0·0001), and death (0·70; 0·25-1·97; p=0·50). Dose-limiting toxicity rates were similar between the fixed-dose (24·1 per 100 patient-years) and MTD phases (23·2 per 100 patient-years; 0·97; 0·70-1·35; p=0·86). Grade 3 and 4 adverse events were infrequent (18·5 per 100 patient-years) and included malaria infection, non-malarial infections, vaso-occlusive pain, and acute chest syndrome. Serious adverse events were uncommon (3·6 per 100 patient-years) and included malaria infections, parvovirus-associated anaemia, sepsis, and stroke, with no treatment-related deaths., Interpretation: Hydroxyurea dose escalation to MTD with dose optimisation significantly improved clinical responses and treatment outcomes, without increasing toxicities in children with sickle cell anaemia in sub-Saharan Africa., Funding: US National Heart, Lung, and Blood Institute and Cincinnati Children's Research Foundation., Competing Interests: Declaration of interests REW receives hydroxyurea donations from Bristol Myers Squibb and Addmedica; research donations from Hemex Health; and serves as Medical Advisor to Nova Laboratories. BA served on the Medical Advisory Board for Global Blood Therapeutics, Pfizer, Agios, and Bluebird Bio and receives research support from Pfizer and Bluebird Bio. All other authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)

Background: Hydroxyurea (HU) is a commonly used first-line treatment in patients with polycythemia vera (PV). However, approximately 15%-24% of PV patients report intolerance and resistance to HU., Methods: This phase IV, European, real-world, observational study assessed the efficacy and safety of ruxolitinib in PV patients who were resistant and/or intolerant to HU, with a 24-month follow-up. The primary objective was to describe the profile and disease burden of PV patients., Results: In the 350 enrolled patients, 70% were >60 years old. Most patients (59.4%) had received ≥1 phlebotomy in the 12 months prior to the first dose of ruxolitinib. Overall, 68.2% of patients achieved hematocrit control with 92.3% patients having hematocrit <45% and 35.4% achieved hematologic remission at month 24. 85.1% of patients had no phlebotomies during the study. Treatment-related adverse events were reported in 54.3% of patients and the most common event was anemia (22.6%). Of the 10 reported deaths, two were suspected to be study drug-related., Conclusion: This study demonstrates that ruxolitinib treatment in PV maintains durable hematocrit control with a decrease in the number of phlebotomies in the majority of patients and was generally well tolerated., (© 2023 The Authors. European Journal of Haematology published by John Wiley & Sons Ltd.)

Hydroxyurea reduces the frequency of vaso-occlusive complications, increases hemoglobin, and decreases mortality in sickle cell disease (SCD). Although current guidelines recommend escalation to maximum tolerated dose (MTD), the use of fixed low-dose hydroxyurea is common in low-resource countries. We conducted a systematic review and meta-analysis to evaluate the efficacy of escalated doses versus fixed low-dose of hydroxyurea in adults with SCD. Nine studies were included in the quantitative synthesis, four evaluating fixed low-dose and five evaluating escalated doses of hydroxyurea. Average daily doses of hydroxyurea in the fixed low-dose and escalated dose studies were ~10 and 22 mg/kg, respectively. There was no difference in the estimate of vaso-occlusive crisis rate between escalated and fixed low-dose studies (p = .73). The mean difference in hemoglobin from baseline to follow-up was greater for fixed low-dose than escalated dose studies (1.07 g/dL vs. 0.54 g/dL, p = .01). No difference was seen in the mean estimate of fetal hemoglobin. Despite limited eligible studies and substantial heterogeneity of effect between the studies for several outcomes, there appears to be clinical equipoise regarding the most appropriate hydroxyurea dosing regimen in adults with SCD. Controlled studies of hydroxyurea at MTD versus fixed low-dose in adults with SCD are required., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background and Objectives : Hydroxyurea is a crucial treatment for sickle cell disease (SCD), but some patients' adherence to it remains suboptimal. Understanding patients' perspectives on SCD and HU is essential for improving adherence. This study aimed to assess hydroxyurea adherence and patients' perceptions of SCD and hydroxyurea among SCD patients in the Jazan region of Saudi Arabia. Materials and Methods : This cross-sectional study collected data from 217 SCD patients using self-administered questionnaires from August 2022 to January 2023. The survey covered patient demographics, SCD consequences, and other clinical data. We used the Brief Illness Perception Questionnaire (B-IPQ) to measure patients' disease perception and the 8-item Morisky Medication Adherence Scale (MMAS-8) to evaluate patients' adherence to HU. Data were analysed using descriptive, t -test, and chi-square tests, and the p -value was set at <0.05 for significance. Results : More than half of the patients were male, with a mean age of 28.09 ± 8.40 years. About 57.6% of the patients were currently using HU. About 81.6% of HU users reported low adherence. The adherence was lower among individuals with infections/recurrent infections and in patients who received repeated blood transfusions. ICU admission, blood transfusion, and certain SCD complications were associated with HU use. Male patients had a higher perception of SCD consequences, concern, and understanding. ICU-admitted and recurrent hospitalized patients had a higher perception of the SCD-related consequences, symptoms, concerns, and emotional responses. Conclusions : HU seems a well-established and efficacious disease-modifying agent, but its underutilization for SCD patients remains challenging. To overcome the adherence challenges, healthcare providers must educate SCD patients about the role of hydroxyurea in lowering disease severity and addressing side effects to obtain maximum benefits. Healthcare providers may consider tailored educational interventions to improve adherence, particularly for patients with infections, recurrent hospitalizations, or repeated blood transfusions. Further research is needed to identify strategies for improving hydroxyurea adherence and patient education among SCD patients.

Sickle cell disease (SCD) is an inherited red blood cell disorder associated with frequent painful events and organ damage. Hydroxyurea (HU) is the recommended evidence-based treatment of SCD. However, among patients eligible for HU, prescription rates are low. Utilizing a scoping review approach, we summarized and synthesized relevant findings regarding provider barriers and facilitators to the prescription of HU in youth and adults with SCD and provided suggestions for future implementation strategies to improve prescription rates. Relevant databases were searched using specified search terms. Articles reporting provider barriers and/or facilitators to prescribing HU were included. A total of 10 studies met the inclusion criteria. Common barriers to the prescription of HU identified by providers included: doubts around patients' adherence to HU and their engaging in required testing, concerns about side effects, lack of knowledge, cost and patient concerns about side effects. Facilitators to the prescription of HU included beliefs in the effectiveness of HU, provider demographics and knowledge. Findings suggest significant provider biases exist, particularly in the form of negative perceptions towards patients' ability to adhere to taking HU and engaging in the required follow-up. Improving provider knowledge and attitudes towards HU and SCD may help improve low prescription rates., (© 2023 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Growth impairment is a known complication of sickle cell disease (SCD). Few studies explored the potential effects of hydroxyurea (HU) on growth in children with SCD in relation to HU dose and response. This is a prospective study conducted at Sultan Qaboos University Hospital, Oman, and included 91 SCD patients with age below 16 years when started on HU, aiming to explore the potential effect/s of HU on growth parameters of older children with SCD in relation to their clinical improvement and the dose required for this improvement. Weight, height, and body mass index (BMI) were collected at baseline, 6 and 18 months after initiation. Anthropometric data were compared to WHO standards. Initial height and BMI Z scores (HAZ and WAZ) were lower compared to WHO norms. HAZ and WAZ did not change significantly after 6 and 18 months on HU therapy. However, BMI Z-scores improved significantly after 6 and 18 months of follow-up (p value 0.044 and 0.028 respectively). No significant changes were observed in WAZ or HAZ among patients on low dose versus those on high dose. BMI Z score improved significantly after 18 months of low dose group (p = 0.014) but did not change in those on high dose HU. In conclusion, HU therapy did not adversely affect weight and height growth in older children with SCD. BMI Z scores improved at 18 months in patients on low dose but not in those on high dose (p = 0.014).

Liver fibrosis results from excessive proliferation of, and collagen production by hepatic stellate cells (HSCs) that is caused by chronic liver injury. No drugs are available to cure liver fibrosis. Hydroxyurea is an anti-proliferative drug that is used in benign and malignant disorders. Here, we studied the effect of hydroxyurea on primary HSCs and its anti-fibrotic effect in the CCl 4 mouse model of liver fibrosis. Primary rat HSCs were cultured in the absence or presence of hydroxyurea (0.1-1.0 mmol/L). CCl 4 or vehicle was administered to C57BL/6/J mice for 4 weeks, with or without hydroxyurea (100 mg/kg/day) co-treatment. We used real-time cell proliferation analysis, Oil Red O (lipid droplet) staining, immunohistochemistry, Acridine Orange staining (apoptosis), Sytox green staining (necrosis), RT-qPCR, ELISA, and Western Blotting for analysis. Hydroxyurea dose-dependently suppressed lipid droplet-loss and mRNA levels of Col1α1 and Acta2 in transdifferentiating HSCs. In fully-activated HSCs, hydroxyurea dose-dependently attenuated PCNA protein levels and BrdU incorporation, but did not reverse Col1α1 and Acta2 mRNA expression. Hydroxyurea did not induce apoptosis or necrosis in HSCs or hepatocytes. Hydroxyurea suppressed accumulation of desmin-positive HSCs and hepatic collagen deposition after CCl 4 treatment. CCl 4 -induced regenerative hepatocyte proliferation, Col1α1 and Acta2 mRNA expression and α-SMA protein levels were not affected. This study demonstrates that hydroxyurea inhibits HSC proliferation in vitro and attenuates early development of liver fibrosis in vivo, while preserving hepatocyte regeneration after toxic insults by CCl 4. Thus, hydroxyurea may have therapeutic value against liver fibrosis., (© 2023 The Authors. The FASEB Journal published by Wiley Periodicals LLC on behalf of Federation of American Societies for Experimental Biology.)

Hydroxyurea (HU), a drug for treating cancers of the blood and the management of sickle cell anemia, induces hypogonadism in males. However, the impact of HU on testicular architecture and function, as well as its effects on the resumption of male fertility following treatment withdrawal, remain poorly understood. We used adult male mice to determine whether HU-induced hypogonadism is reversible. Fertility indices of mice treated with HU daily for ~1 sperm cycle (2 months) were compared with those of their control counterparts. All indices of fertility were significantly reduced among mice treated with HU compared to controls. Interestingly, significant improvements in fertility indices were apparent after a 4-month withdrawal from HU treatment (testis weight: month 1 post-HU withdrawal (M1): HU, 0.09 ± 0.01 vs. control, 0.33 ± 0.03; M4: HU, 0.26 ± 0.03 vs. control, 0.37 ± 0.04 g); sperm motility (M1: HU,12 vs. 59; M4: HU, 45 vs. control, 61%; sperm density (M1: HU, 1.3 ± 0.3 vs. control, 15.7 ± 0.9; M4: HU, 8.1 ± 2.5 vs. control, 16.8 ± 1.9 million). Further, circulating testosterone increased in the 4th month following HU withdrawal and was comparable to that of controls. When a mating experiment was conducted, recovering males sired viable offspring with untreated females albeit at a lower rate than control males ( p < 0.05); therefore, qualifying HU as a potential candidate for male contraception.

Sickle cell anemia (SCA) is an inherited disease affecting the hemoglobin that is particularly common in sub-Saharan Africa. Although monogenic, phenotypes are markedly heterogeneous in terms of severity and life span. Hydroxyurea is still the most common treatment for these patients, and the response to treatment is highly variable and seems to be an inherited trait. Therefore, identifying the variants that might predict hydroxyurea response is important for identifying patients who will have a poorer or non-response to treatment, and the ones that are more prone to suffer from severe side effects. In the present pharmacogenetic study, we analyzed the exons of 77 genes described in the literature as potentially associated with hydroxyurea metabolism in Angolan children treated with hydroxyurea and evaluated the drug response considering fetal hemoglobin levels, other hematological and biochemical parameters, hemolysis, number of vaso-occlusive crises and hospitalizations. Thirty variants were identified in 18 of those genes as possibly associated with drug response, five of them in gene DCHS2. Other polymorphisms in this gene were also associated with hematological, biochemical and clinical parameters. Further research examining the maximum tolerated dose and fixed dose with a larger sample size is necessary to corroborate these findings.

Sickle cell anemia (SCA) is a life-threatening genetic condition contributing to high-risk pregnancies affecting both the mother and fetus. With improved management of children with SCA, this life-threatening hematological disorder has evolved into a chronic disease of adults, and consequently parenthood has now become a possible and important life goal for many patients. Providing continuous management with healthy red blood cell function and avoiding SCA-associated complications, such as pain crises, acute chest syndrome, and stroke, are crucial for a healthy pregnancy. Despite its excellent safety profile in non-pregnant adults and children, and based on theoretical concerns derived from data using animal models and supraphysiological dosing, hydroxyurea is currently contraindicated for pregnant and lactating women with SCA. Clinical experience of hydroxyurea use during pregnancy is increasingly reported, however, and has shown inconsistent results of fetal or infant adverse effects. How the hydroxyurea exposure level may correlate with pregnancy outcomes is still unclear. Accordingly, efforts should be made to systemically evaluate exposure and safety of hydroxyurea treatment during pregnancy and lactation. Novel approaches such as physiologically based pharmacokinetic (PBPK) modeling, coupled with the ex vivo human placental cotyledon perfusion assay, provide opportunities to understand hydroxyurea exposure not only in pregnant women but also in the developing fetus. Combined with animal data, research using these approaches might be able to define safe and effective hydroxyurea dosing regimens for pregnant and lactating women with SCA, when the benefits of continuing hydroxyurea treatment likely outweigh the risks of non-treatment, by avoiding substantial morbidity and even mortality for both mothers and infants., (© 2023 The Authors. Pharmacotherapy: The Journal of Human Pharmacology and Drug Therapy published by Wiley Periodicals LLC on behalf of Pharmacotherapy Publications, Inc.)

Background: Recognizing intolerance or resistance to hydroxyurea (HU), which is related to the high risk of a disease transformation and reduced survival in essential thrombocythemia (ET), is crucial to making a reasonable decision about second-line therapy. We assessed the prognostic impact of the modified European LeukemiaNet (mELN) criteria used in a recent MAJIC-ET trial by analyzing the incidence of resistance or intolerance to HU and the survival outcome compared with those of the ELN criteria., Methods: We retrospectively compared the development of HU resistance or intolerance according to the ELN and mELN criteria for 148 high-risk ET patients receiving HU between 2014 and 2018. The maximum tolerated dose for defining HU resistance was used in the mELN criteria., Results: The median age of patients was 65 years (range, 36-87), with a median follow-up of 3.6 years (range, 1.1-6.4). Two thromboembolic events were observed during HU treatment. When applying the ELN criteria, 10 patients (6.9%) were resistant (n = 5 [3.4%]) or intolerant (n = 5 [3.4%]) to HU in comparison with 22 patients (15%, 14 [9.8%]) resistant and 8 [5.5%] intolerant when applying the mELN criteria. Transformation to myelofibrosis and acute myeloid leukemia occurred in 2 (1.4%) patients and 1 (0.7%) patient, respectively, as defined by the ELN criteria compared with 3 (2.1%) and 2 (1.4%) patients as defined by the mELN criteria. In multivariate analysis of transformation-free survival, HU resistance defined by the mELN criteria but not the ELN criteria was an independent prognostic factor. In addition, HU resistance as defined by both sets of criteria was an independent risk factor for inferior overall survival. Intolerance of HU did not have any prognostic impact on survival., Conclusions: The mELN criteria are useful for identifying high-risk ET patients who might be eligible for second-line therapy in practice, which should be validated in a prospective setting., (© 2023 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Introduction: We sought to investigate whether hydroxyurea therapy is associated with the need for surgical splenectomy among patients with sickle cell disease (SCD). We hypothesized that as hydroxyurea gained widespread use, surgical splenectomy among pediatric patients with SCD occurred at a higher rate and older age among those taking hydroxyurea., Methods: In this retrospective cross-sectional study, the Pediatric Health Information System was queried for all SCD International Classification of Diseases 9/10 diagnosis codes and splenectomy procedure codes from January 1, 2005, to December 31, 2020. Hydroxyurea use was defined as at least one hospital admission with hydroxyurea listed as a medication. The rates of surgical splenectomy, age at splenectomy, hospital length of stay, and incidence of blood transfusion during the splenectomy admission were compared among patients receiving hydroxyurea versus those not receiving hydroxyurea. Additional subanalysis was performed in the Hemoglobin-SS, Hemoglobin-SC, and Other cohorts separately., Results: During the study period, 28,520 patients were identified. All patients with SCD receiving hydroxyurea had a significantly higher rate of surgical splenectomy compared with the nontreatment group (7.2% versus 3.2%, P = 0.01). The age at surgical splenectomy was significantly younger among Hemoglobin-SS patients receiving hydroxyurea (5.7 [5.1, 6.4] y versus 6.6 [5.8, 7.4] y; P < 0.01). There were no significant differences in length of stay or incidence of blood transfusion during the surgical splenectomy admission between treatment groups., Conclusions: Hydroxyurea use in children is associated with higher rates of surgical splenectomy and occurs at a younger age in the Hemoglobin-SS population. Although these findings warrant further investigation for causality, it provides useful information to clinicians and patients alike, allowing for more informed decision-making., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Hydroxyurea (HU) (hydroxycarbamide) is used as a therapeutic option in β-thalassaemia to increase fetal haemoglobin, which results in a reduced requirement for blood transfusion. However, a potential serious adverse effect of HU is neutropenia. Abnormal neutrophil maturation and function in β-thalassaemia/HbE patients are well documented. This raises questions about the effect of the drug with regards to the immune response these patients. This study investigated the effects of HU treatment on both innate and adaptive immunity in a cross-sectional study of 28 β-thalassaemia/HbE patients who had received HU treatment (BE+HU) as compared with 22 β-thalassaemia/HbE patients who had not received HU (BE-HU) and 26 normal subjects. The expression of PU.1 and C/EBPβ, transcription factors, which are associated with neutrophil maturation, was significantly reduced in BE+HU patients as compared with BE-HU patients and normal subjects. Interestingly, C3bR expression on neutrophils and their oxidative burst activity in BE+HU were restored to close to normal levels when compared with BE-HU. There was no observed effect of HU on monocytes, myeloid derived suppressor cells (both granulocytic and monocytic subsets), CD4 + T cells, CD8 + T cells, complement levels and serum immunoglobulin levels in this study. The full immunophenotyping analysis in this study indicates that HU therapy in β-thalassaemia/HbE patients does not significantly compromise the immune response., (© 2022 British Society for Haematology and John Wiley & Sons Ltd.)

Determine efficacy and adverse events (AEs) of hydroxyurea (HU) in mast cell activation syndrome (MCAS) patients who were refractory to standard medical therapy. An electronic chart review was performed to find MCAS patients who received HU in a MCAS medical practice. Diagnosis of MCAS was established on the basis of mast cell (MC) activation symptoms in ≥ 5 systems plus ≥ 1 abnormal MC mediators and/or ≥ 20 MC/high power field on duodenal biopsies. Medicines not providing significant clinical improvement prior to HU were tabulated. The following symptoms were evaluated by patients on a 0-10 scale prior to and at the study conclusion: bone pain, abdominal pain, diarrhea, bloating, and nausea. Safety labs were obtained on a regular basis. Twenty out of three hundred ten (8.4%) MCAS patients received HU. Patients included 22 females, average age 42.4 years. Dysautonomia was present in 60%. An average of 10.6 (SD 1.7, range 8-13) medications were used prior to adding HU to various concomitant medications. Average dose of HU was 634 mg. In 20 patients who continued therapy for ≥ 2 months, there was statistically significant reduction of bone pain, abdominal pain, diarrhea, bloating, and nausea. Fourteen patients noted prolonged success with therapy. Six patients stopped HU within 6 weeks owing to AEs. Four patients treated ≥ 2 months had AEs and 2 led to HU cessation. All AEs were reversible. Refractory MCAS patients showed clear significant improvement in bone pain and gastrointestinal symptoms on HU. Systematic monitoring was effective in preventing the occurrence of severe HU-induced adverse events., (© 2022. The Author(s).)

Background: Hydroxyurea (HU) has been widely used in clinical practice to manage patients with non-transfusion dependent thalassemia (NTDT). Few data are available about the effects of its administration in Italian patients. We assessed hematological and non-hematological outcomes following short- and long-term exposure to HU., Research Design and Methods: We considered 71 NTDT patients (30 females) enrolled in the Myocardial Iron Overload in Thalassemia Network and treated for >12 months with HU., Results: The mean duration of HU treatment was 8.23±5.79 years, starting at a mean age of 37.02±12.06 years. A significant increase in hemoglobin and mean corpuscular volume values and a down-regulation of all erythropoietic and/or hemolysis indices were detected after at least 12 months of treatment. In 28 patients the hemoglobin increase was ≥1.0 g/dl, associated with a higher HU dose. The hematological response dropped in long-term treatment. A favorable impact of HU treatment in limiting the progression of several complications typical of NTDT syndrome was observed., Conclusion: Our findings seemed to suggest that in several NTDT patients HU could be still a valid option to limit the advance in overall disease clinical burden without carrying significant adverse events and increase in mortality.

Patients diagnosed with high-risk essential thrombocythemia (ET) have limited treatment options to reduce the risk of thrombosis and lessen the progression of the disease by targeting the molecular source. Hydroxyurea is the recommended treatment, but many patients experience resistance or intolerance. Anagrelide is an approved second-line option for ET, but concerns of a higher frequency of disease transformation may affect its role as a suitable long-term option. Interferons have been evaluated in myeloproliferative neoplasms for over 30 years, but early formulations had safety and tolerability issues. SURPASS-ET (NCT04285086) is a phase III, open-label, multicenter, global, randomized, active-controlled trial that will evaluate the safety, efficacy, tolerability and pharmacokinetics of ropeginterferon alfa-2b compared with anagrelide as second-line therapy in high-risk ET.

Background & Objectives: Sickle cell disease (SCD) constitutes frequently inherited haemoglobin disorders and poses a significant health burden in India. Hydroxyurea (HU), the most commonly used drug, has shown promising results in the clinical management of SCD. The present systematic review was undertaken to assess the efficacy and toxicity of HU in Indian sickle cell patients., Methods: A systematic review of studies on HU therapy was conducted to identify the application of HU and its outcome(s) across India. PubMed, Scopus and Cochrane Library was used as data sources for various studies on the efficacy and toxicity of HU therapy for treatment for SCD in India published between January 2001 and October 2021. Two authors independently extracted the data on study design, patient characteristics and therapeutic outcomes of HU in order to determine the study quality of the present review., Results: Overall, 14 studies were included for a systematic analysis. Of these 11 were prospective, two cross-sectional and one double-blind randomized controlled trial. Low-dose HU (10 mg/kg/day) was found to reduce the rates of vaso-occlusive crisis and hospitalization as well as decreased the requirement of blood transfusion in SCD patients. The foetal haemoglobin (HbF) level was recorded in 13 (80%) studies all of whom reported an elevation in the HbF levels, with a mean increase in per cent HbF from 15.8 to 21.4 per cent across studies. The common adverse events were reversible, mild-to-moderate cytopenia and anaemia., Interpretation & Conclusions: The findings of the present review suggest that there is still insufficient information presently to determine the long-term or major adverse effects on organ damage, fertility as well as pregnancy on the use of HU therapy for SCD. Long-term multi-centric studies are thus required to address these problems.

Vaso-occlusive episodes (VOEs) are a major concern in patients with sickle cell disease (SCD). Exposure to systemic corticosteroids has been suspected to increase the occurrence of VOEs in case reports or series. No comparative study has been conducted to investigate this risk, which is still debated. Several clinical trials demonstrated the effectiveness of corticosteroids for the treatment of VOEs, but with increased rates of readmission. The aim of the study was to assess the risk of hospitalization for VOE associated with exposure to systemic corticosteroids in patients with SCD. We used a case-case-time-control design in a nationwide population-based cohort built in the French national health insurance database between 2010 and 2018. The population included all patients with SCD with at least 1 hospitalization for VOE. Corticosteroids were identified using out-of-hospital dispensing data. The outcome was the first hospitalization for VOE. The case-case-time-control design induces self-adjustment for time-invariant confounders, including genotype. Analyses were adjusted for time-dependent confounders (infections, red blood transfusions) and stratified by exposure to hydroxyurea. Overall, 5151 patients were included in the main analysis. Corticosteroid exposure was significantly associated with the occurrence of hospitalizations for VOEs: adjusted odds ratio, 3.8; 95% confidence interval [CI], 2.4-5.6). In patients exposed to hydroxyurea, the adjusted odds ratio was 2.6 (95% CI, 1.1-6.4); it was 4.0 (95% CI, 2.5-6.3) in unexposed patients. These results were consistent in children and adults. In conclusion, systemic corticosteroids were associated to an increased risk of hospitalization for VOEs and should be limited in patients with SCD., (© 2022 by The American Society of Hematology.)

Competing Interests: Competing interests: None declared.

The presence of leg ulcers in individuals with sickle cell disease often represents an early sign of vasculopathy and future end organ damage. Pathophysiological mechanisms of formation and evolution of leg ulcers are poorly understood; nevertheless, HbF has been associated with lower incidence of leg ulcers, while hydroxyurea has been correlated with high risk of leg ulcers. As a result, there is hesitation regarding hydroxyurea use in patients with SCD and leg ulcers. In this study, we aim to define (1) a target of HbF that offers protection against leg ulcer development and (2) the impact of hydroxyurea therapy on leg ulcer prevalence. Our study demonstrated that in order to reduce leg ulcer incidence by one-third, a HbF > 25% is needed, a threshold not commonly reached and maintained in the adult SCD population. Importantly, leg ulcer incidence appears to be independent of HU use (p = 0.50). Our interpretation of this data is that the use of HU in a patient with SCD and leg ulcers should be guided by a careful assessment of risks and benefits of this therapeutic modality., (© 2022. This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.)

Objective: To describe the epidemiological, clinical and therapeutic characteristics of a series of sickle cell disease cases collected in Mauritania over a three-year period., Methods: This is a descriptive study of the profile of sickle cell disease, diagnosed in Mauritania, from January 1, 2015 to December 31, 2017, at the outpatient clinics of the National Hospital Center and at the Mauritanian Association for the Support of Sickle Cell Patients. Patients were included following diagnostic confirmation by hemoglobin electrophoresis., Results: During the study period, a total of 135 patients were included (79 female and 56 male), i.e. a sex ratio of 0.7 and an average age of 24 years (extremes: 9 months -77 years). All Mauritanian ethnic groups were affected by sickle cell disease, mainly the Peulths (63.7%). Sickle cell disease was found in eight wilayas, particularly Brakna (39%). The age of diagnosis was between 3 and 5 years, in 48% of patients. Sickle cell disease was discovered at the stage of complications in twelve patients. There are three types of sickle cell phenotypes: SS (54%), AS (40%) and SC (6%). In addition to transfusion, preventive treatment consisted of folic acid (n=53), hydroxyurea (n=14), and long-term antibiotic prophylaxis (n=3)., Conclusion: The profile of sickle cell disease in Mauritania remains attributed to the lack of an active screening strategy and rapid diagnosis, hence the importance of developing a national program for early detection and management.

Introduction : Hydroxyurea (HU) is an S-phase specific oral chemotherapeutic agent that inhibits ribonucleotide diphosphate reductase. It is the most common used cytoreductive drug in patients (pts) with BCR-ABL1 negative myeloproliferative neoplasms (MPN) and sickle cell disease (SCD). The World Health Organization lists HU as an "essential drug". Although most patients tolerate HU well, cutaneous adverse events (CAE) are frequent side effects and may limit its long-term use. This has become increasingly evident in recent years, especially in MPN patients, where CAE were previously underestimated and underdiagnosed. Areas covered : In this review, we present the available literature on HU-related CAE in MPN patients. In particular, data from a recently published and so far, only prospective non-interventional study investigating CAE in 172 MPN patients will be discussed in detail and compared with previously available data. Finally, we give an overview of the management of HU-related CAE in MPN patients and provide recommendations on the practical clinical approach. Expert opinion : In clinical practice, HU associated CAE are common and have important diagnostic and therapeutic consequences. Therefore, they should be considered in all MPN patients treated with HU in the future.

Over the past 20 years, hydroxyurea (HU) has emerged as an effective therapeutic agent in thalassemic patients to improve anemia and decrease the transfusion dependency. We evaluated long-term safety and clinical response to HU in patients with non-transfusion-dependent β-thalassemia (NTDT). In this retrospective study, medical records of 181 patients with NTDT were evaluated during October to December 2020 in Southern Iran. No requirement to blood transfusion was considered as sustained transfusion independence response. All patients were regularly examined and monitored for the occurrence of any adverse event (AE) of HU. The mean duration of HU consumption ± SD was 18.2 ± 4.0 (8-22) years. Overall, 149 patients (82.3%) had sustained transfusion independence response. β-globin gene mutations and XmnI polymorphisms were not significantly associated with clinical response (P > 0.05). Mild and transient AEs were reported in 60 patients (33%) with no requirement to drug interruption. Hydroxyurea with the dose of 8-15 mg/kg can be used as a safe and effective treatment in NTDT patients. It was well tolerated in long term without any serious complication or secondary malignancy. No relationship between XmnI or β-globin gene mutations with HU response was observed in this geographic area of the world., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Competing Interests: The authors declare no conflict of interest.

Introduction: Sickle cell anemia (SCA) results in numerous adverse effects on the brain, including neurocognitive dysfunction. Hydroxyurea has been utilized extensively for management of SCA, but its effects on brain function have not been established., Methods: We examined prospectively the effects of 1 year of treatment with hydroxyurea on brain function in children with SCA (HbSS/HbSβ 0 -thalassemia) by baseline and exit evaluations, including comprehensive neurocognitive testing, transcranial Doppler ultrasound (TCD), and brain MRI (silent cerebral infarcts [SCI], gray matter cerebral blood flow [GM-CBF], and blood oxygen level-dependent [BOLD] signal from visual stimulation)., Results: Nineteen patients with SCA, mean age 12.4 years (range 7.2-17.8), were evaluated. At baseline, subjects had these mean values: full-scale IQ (FSIQ) 82.8, TCD velocity 133 cm/s, GM-CBF 64.4 ml/100 g/min, BOLD signal 2.34% increase, and frequency of SCI 47%. After 1 year of hydroxyurea, there were increases in FSIQ (+2, p = .059) and reading passage comprehension (+4, p = .033), a significant decrease in TCD velocity (-11 cm/s, p = .007), and no significant changes in GM-CBF, BOLD, or SCI frequency. Hemoglobin F (HbF) was associated with passage comprehension, hemoglobin with lower TCD velocity, and lower GM-CBF with greater working memory. Higher BOLD signal was associated with higher processing speed and lower TCD velocity with higher math fluency., Discussion: Improvements in neurocognition and decreased TCD velocity following 1 year of treatment support hydroxyurea use for improving neurocognitive outcomes in SCA. Understanding the mechanisms of benefit, as indicated by relationships of neurocognitive function with HbF, hemoglobin, and CBF, requires further evaluation., (© 2021 Wiley Periodicals LLC.)

Myeloproliferative neoplasms are rare at a young age, and few reports have described the disease characteristics and outcomes in this group. This study aimed to elucidate the clinical course of essential thrombocythemia (ET) and polycythemia vera (PV) in children and young adults aged <39 years focusing on thromboembolic events (TE) and second primary malignancies (SPMs). A total of 990 patients who were diagnosed from 2008 to 2017 were included by analyzing the Health Insurance Review and Assessment Service database in Korea. The incidence was 2.53 per 1,000,000 for ET (643 patients; 276 male patients; median 31 years) and 1.37 per 1,000,000 for PV (347 patients; 309 male patients; median 32 years). Three ET patients developed secondary acute myelogenous leukemia and three developed secondary myelofibrosis. The 5-year cumulative incidence of TE was 14.2% in ET and 21.3% in PV. Thus, the incidence was higher in PV; in particular, arterial TE (ATE) was evidently higher in PV than in ET. The 5-year cumulative incidence of SPMs was 2.5% in ET and 2.6% in PV. While the use of both aspirin and hydroxyurea reduced the incidence of ATE, hydroxyurea significantly increased the incidence of SPMs. The incidence of ET and PV was very low, and ET was more common than PV in children and young adults. The high incidence of TE in young patients suggests the importance of thrombosis prevention. However, hydroxyurea appears to increase the incidence of SPMs; therefore, the risks and benefits should be considered., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Several controlled studies have evidenced good efficacy and short-term and mid-term safety profiles for hydroxyurea (HU), which has become the cornerstone for prevention of sickle-cell disease (SCD)-related vaso-occlusive crises. However, there are few large-scale reports on its long-term use and certain caregivers and patients have concerns about its safety. Following the licensing of HU in Europe for children and adults with severe forms of SCD, ESCORT-HU was designed as a Phase IV observational cohort study. It included 1906 participants, of whom 55% were adults. The most common hemoglobin (Hb) genotypes were HbSS (84.7%) and HbSβ+ (7.0%). The median duration of follow-up was 45 months, for a total of 7309 patient-years of observation. The dose of HU after 1 year was 20.6 mg/kg/d for children and 16.3 mg/kg/d for adults. There was a statistically significant decrease in the number of vaso-occlusive episodes lasting >48 h, acute chest syndrome episodes, hospitalizations, and the percentage of patients requiring blood transfusions within the first 12 months relative to the year before enrolment. Neutropenia and thrombocytopenia were the most commonly reported adverse effects. No new HU toxicity was identified. Overall, 125 pregnancies were reported in 101 women and no malformations were observed in the neonates. There were 12 pregnancies for partners of male patients treated with HU. One case of fatal myelodysplastic syndrome was reported, for which a causal association with HU could not be excluded. This cohort study of patients with SCD highlights the positive benefit-to-risk ratio of HU in children and adults., (© 2021 Wiley Periodicals LLC.)

Neurocognitive impairment is common in sickle cell disease (SCD) and is associated with significant functional limitations. In a cross-sectional analysis, we examined the association between hydroxyurea (HU) treatment and neurocognitive functioning from school-age to young adulthood in individuals with SCD. A total of 215 patients with HbSS/HbSβ 0 -thalassaemia (71% HU treated) and 149 patients with HbSC/HbSβ + -thalassaemia (20% HU treated) completed neurocognitive measures at one of four developmental stages: school-age (age 8-9 years), early adolescence (age 12-13 years), late adolescence (age 16-17 years) and young adulthood (ages 19-24 years). For participants with multiple assessments, only the most recent evaluation was included. In multivariable analysis adjusted for social vulnerability, HU treatment and sex, older age was associated with a reduction in overall intelligence quotient (IQ) of 0·55 points per year of life [standard error (SE) = 0·18, false discovery rate adjusted P value (PFDR) = 0.01] for patients with HbSS/HbSβ 0 -thalassaemia. Earlier initiation of HU (n = 152) in HbSS/HbSβ 0 -thalassaemia was associated with higher scores on neurocognitive measures across most domains, including IQ [estimate (SE) 0·77 (0·25)/year, PFDR = 0·01], after adjusting for social vulnerability, sex and treatment duration. These results support the early use of HU to limit the detrimental neurocognitive effects of SCD, while highlighting the need for additional measures to further mitigate neurocognitive deterioration., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

Hydroxyurea is a chemotherapeutic agent used for myeloproliferative disorders and sickle cell anemia that is well known to cause painful mucocutaneous ulcers, typically involving the legs or mouth. However, genital ulcerations due to hydroxyurea therapy are a rare, and likely underrecognized, adverse effect with only a few cases reported in the literature to date. Ulcers of the lower legs caused by hydroxyurea are associated with a diagnostic delay, and this is likely exacerbated in cases of genital ulceration due to a lack of awareness. Herein we present two cases of painful genital ulceration in patients on hydroxyurea therapy. In the first Case, an 87 year-old male with polycythemia vera developed an ulcer on the scrotum, which was assessed initially through virtual visits during the COVID-19 pandemic, and was refractory to topical and oral antibiotic treatments. The second case was a 79 year-old male with essential thrombocythemia and a history of persistent leg ulcers who developed erosions of the glans penis. Both patients experienced complete resolution within weeks of discontinuing hydroxyurea therapy. In conclusion, genital ulcers and erosions induced by hydroxyrea may be underrecognized in clinical practice, but if identified, withdrawal of hydroxyurea leads to quick resolution of these lesions and the associated pain., (Copyright © 2021. Published by Elsevier Ltd.)

Hydroxyurea (hydroxycarbamide) is approved for treating both children and adults with sickle cell anaemia (SCA). Fetal haemoglobin (HbF) induction is the primary treatment response, along with improved anaemia, reduced haemolysis, myelosuppression and decreased endothelial inflammation. Hydroxyurea has proven clinical efficacy for SCA - treatment significantly reduces disease manifestations and prolongs survival. Despite these recognised benefits, long-standing concerns regarding the risks of mutagenic and potentially carcinogenic drug exposure have hampered efforts for broad hydroxyurea use in SCA, although these are based largely on outdated experimental models and treatment experiences with myeloproliferative neoplasms. Consequently, many patients with SCA are not receiving this highly effective disease-modifying therapy. In this review, we describe the concept of genotoxicity and its laboratory measurements, summarise hydroxyurea-associated data from both preclinical and clinical studies, and discuss carcinogenic potential. The genotoxicity results clearly demonstrate that hydroxyurea does not directly bind DNA and is not mutagenic. Rather, its genotoxic effects are limited to indirect clastogenicity occurring in select cell types, and only when high dose and time thresholds are exceeded. This absence of mutagenic activity is consistent with the observed lack of any compelling carcinogenic potential. Since hydroxyurea therapy for SCA carries minimal carcinogenic risks, the current drug labelling should be modified accordingly, and prescribing practices should be broadened to allow better access and increased utilisation of this highly effective drug., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

Background: Although effectiveness of hydroxyurea (HU) in sickle cell disease is well established, unanswered questions persist about its use in African children. We determined real-life issues of acceptability, availability, and monitoring of HU use in Nigeria., Methods: A retrospective longitudinal review of laboratory data of patients on HU was done from case files, followed by a cross-sectional survey that captured families' perception of medication and clinic adherence, laboratory tests, benefits, side effects, and acceptability., Results: One hundred sixteen patients (1.2-17 years) received HU (mean ± SD = 18.5 ± 4.3 mg/kg/day) in 33 months. Eighty-nine had laboratory analysis. Dose escalation was the initial goal, but only 80% of patients had some form of it. Parents reported improvement in general well-being and reduction in bone pain episodes, hospital admissions, and blood transfusion. While most parents (89.5%) reported satisfaction with HU, 61% reported dissatisfaction with daily drug use, and the frequency and cost of monitoring. Sixteen percent voluntarily stopped therapy. Adherence to daily HU was 88.8%, doctor's appointments 24.5%, hematology tests 18.9%, and organ function tests 37.4%. There were no significant toxicities. Significant increases in hemoglobin, hemoglobin F and mean corpuscular volume, and reduction in absolute neutrophil count occurred despite inconsistent dose escalation., Conclusion: HU (10-15 mg/kg/day starting dose) is safe and seems effective and acceptable to parents. Parental commitment to therapy, pre-HU education (that continues during therapy), provision of affordable HU, and subsidized laboratory tests are important considerations for initiating therapy. Special HU clinics may facilitate dose escalation and reduce frequency of monitoring. Studies are needed on feasibility of maximum tolerable dose HU protocols in sub-Saharan Africa without compromising safety., (© 2021 Wiley Periodicals LLC.)

Background: Without early initiation of disease-modifying therapy, the acute and chronic complications of sickle cell anemia (SCA) begin early in childhood and progress throughout life. Hydroxyurea is a safe and effective medication that reduces or prevents most SCA-related complications. Despite recommendations to prescribe hydroxyurea for all children with SCA as young as 9 months, utilization remains low., Procedure: We completed a retrospective review of hydroxyurea-prescribing practices and associated clinical outcomes at our institution over a 10-year period before and after the 2014 National Heart, Lung, and Blood Institute (NHLBI) recommendations to use hydroxyurea for all children with SCA., Results: Hydroxyurea use more than doubled within our pediatric SCA population from 43% in 2010 to 95% in 2019. The age of hydroxyurea initiation was significantly younger during 2014-2019 compared to 2010-2013 (median 2 years vs. 6 years, p ≤ .001). With this change in clinical practice, nearly all (69/71 = 97%) children born after 2013 received disease-modifying therapy by the end of 2019, primarily hydroxyurea (93%). Concurrently, the number of SCA-related admissions significantly decreased from 67/100 patient-years in 2010 to 39/100 patient-years in 2019 (p < .001)., Conclusion: The early and universal prescription of hydroxyurea for children with SCA is the standard of care. Here, we demonstrate that a careful and deliberate commitment to follow this guideline in clinical practice is feasible and results in measurable improvements in clinical outcomes. Our approach and improved outcomes can serve as a model for other programs to expand their hydroxyurea use for more children with SCA., (© 2021 Wiley Periodicals LLC.)

Introduction: Hemoglobin (Hb)-F inducers are known to improve Hb level and transfusion dependence in thalassemia. This pilot study was conducted to assess the efficacy and safety of Hb-F inducer thalidomide compared to hydroxyurea (HU) in Hb E-β thalassemia patients., Methods: This was a prospective interventional single-centre study with 45 Hb E-beta thalassemia patients equally divided into group-I (thalidomide+folic acid), group-II (HU + folic acid) and group-III (folic acid). Response was assessed at various time intervals with 12-months follow up period. Primary end points were increment in Hb, Hb-F level and improvement in transfusion requirement; secondary end point were tolerability and safety., Results: There was 100% responder (R: Hb-increment ≥1 g/dl) in group-I with 66.67% major responder (MaR: Hb-increment ≥2 g/dl), while there were 40% and 0% responder in group-II and III respectively. Hb-increment was significantly (p-value <0.0001) better in thalidomide arm compared to HU. The Hb-increment was attributable to both increase in Hb-F levels and reduction in ineffective erythropoiesis in thalidomide arm. Transfusion reduction was significantly better in group-I compared to group-II (100% vs 34%). No severe adverse effects was reported by patients of any group., Conclusion: Thalidomide showed a persistent significant Hb-increment and transfusion independence in Hb E-β thalassemia patients compared to HU., (Copyright © 2021 Elsevier Inc. All rights reserved.)