Months Of Hydroxyurea Therapy Research Articles

Neurocognitive Improvement with Hydroxyurea Therapy in Children with Sickle Cell Anemia in Uganda: Interim Analysis at Month 18

Introduction: Cerebrovascular injury can lead to neurocognitive impairment in children with sickle cell anemia (SCA). The prospective impact of hydroxyurea therapy on neurocognitive function has not been previously reported in a large sample of children with SCA in sub-Saharan Africa. We assessed the impact of hydroxyurea therapy at the trial's18-month midpoint on neurocognitive function compared to baseline assessments and to non-SCA controls. Methods: A sample of267 children with SCA, ages 3 to 9 years, were randomly selected for screening and enrollment from eligible patients who attended the Mulago Hospital Sickle Cell Clinic (MHSCC). BRAIN SAFE II is an open label hydroxyurea treatment trial with escalation to maximal tolerated dose. Primary outcomes are stroke, stroke risk and neurocognitive assessment. Controls were aged 3 to 12 years and siblings/relatives of participants with SCA.Attention, cognition and executive function were assessed for all participants by age-appropriate neurocognitive testing. Controlsestablished test z-scores for each age. Baseline (month 0) SCA group z-scores were compared to the controls and to the SCA sample at trial month 18. Results: At trial baseline, SCA trial participants (n=267) were younger than the control group (mean age 5.1±1.7 vs. 7.1± 3.9 years, p<0.001), had lower weight-for-age ( p=0.03) and had similar socio-economic score and caregiver age and educational attainment. Participants had lower z-scores in attention (p<0.001) and neurocognitive ability (p<0.001), and in executive function ( p=0.001) in a total of 15 of 17 subtests. After 18 months of hydroxyurea therapy (mean dose 25.4mg/kg) for all active SCA participants (95.1%) (n=254), significant improvements in z-scores were seen at 18 months in attention ( p<0.001), all 4 subtests for cognitive ability ( p<0.001) and in 3 of 6 subtests of executive function ( p=0.003 to <0.001). Conclusion: After 18 months of hydroxyurea therapy reaching MTD dosing, children showed significant improvements in attention and cognition, with more modest improvements in executive function. Their scores moved closer to those from non-SCA controls in most subtests. These findings suggest that hydroxyurea therapy may play an important role in enhancing overall neurocognitive function in children with SCA. Trial procedures are ongoing to assess the effects from longer-term therapy.

Role of microRNA in hydroxyurea mediated HbF induction in sickle cell anaemia patients

Hydroxyurea (HU) is found to be beneficial in sickle cell anaemia (SCA) patients, due to its ability to increase foetal haemoglobin (HbF), however, patients show a variable response. Differences in HbF levels are attributed to many factors; but, the role of miRNA in HbF regulation is sparsely investigated. In this study, we evaluated the effect of miRNA expression on HbF induction in relation to hydroxyurea therapy in 30 normal controls, 30 SCA patients at baseline, 20 patients after 3 and 6 months of hydroxyurea (HU) therapy. HbF levels were measured by HPLC. Total RNA and miRNA were extracted from CD71+ erythroid cells and the expression was determined using Taqman probes. The mean HbF level increased 7.54 ± 2.44 fold, after 3 months of HU therapy. After the HU therapy 8 miRNAs were significantly up-regulated while 2 were down-regulated. The increase in miR-210, miR16-1, and miR-29a expression and decrease in miR-96 expression were strongly associated with the HU mediated HbF induction. Post HU therapy, decreased miR-96 expression negatively correlate with HbF and γ-globin gene while increased expression of miR-210, miR-16-1 and miR-29a post HU therapy positively corelate with HbF and γ-globin gene. Thus, suggest that miR-210, miR-16-1 and miR-29a are positive regulator of γ-globin gene and miR-96 is negative regulator of γ-globin gene. The study suggests the role of miR-210, miR16-1, miR-29a, and miR-96 in γ-globin gene regulation leading to HbF induction. Identification of the relevant protein targets might be useful for understanding the HU mediated HbF induction.

Individualized, PK-Guided Dosing of Hydroxyurea Is Not Associated with Increased Hematologic Toxicity Compared to Weight-Based Initial Dosing: Interim Results from the Hops Trial

Introduction: Initiation of hydroxyurea (HU) in the first year of life is becoming an increasingly accepted standard of care for children with sickle cell anemia (SCA). Stepwise dose escalation to maximum tolerated dose (MTD) typically starts empirically at 20 mg/kg/day, based on early studies of adults and the subsequent BABY HUG study. However, recent results from the NOHARM trial in Uganda demonstrated the clinical superiority and similar safety profile of a higher initial dose (25 mg/kg with dose escalation) compared to fixed 20 mg/kg dosing. Despite these findings, many providers remain hesitant to start at doses higher than 20 mg/kg/day, mostly related to possible hematologic toxicity. Similarly, there is great variability in dose escalation strategies and variation in laboratory thresholds used to decide whether to hold or dose escalate HU therapy. Study Design and Rationale: Recognizing the significant interpatient variability in dosing and the importance in optimizing exposure, we have developed an individualized, pharmacokinetics (PK)-guided dosing strategy of HU for children with SCA. The single center TREAT trial demonstrated that an individualized dosing strategy, using higher starting doses (27.7 ± 4.9 mg/kg/day) was feasible and effective, achieving MTD almost immediately and HbF ≥30% for most patients. To further validate these results, the follow-up Hydroxyurea Optimization through Precision Study (HOPS, NCT03789591) is a randomized, multicenter trial comparing standard, weight-based initial dosing with conventional dose-escalation vs. PK-guided initial dosing for children with SCD as they initiate HU therapy. Participants (ages 6 months through 21 years), recruited from 15 pediatric sickle cell centers across the US, are randomized to receive HU either using a starting dose of 20 mg/kg/day or a PK-guided dose. Participants in both arms subsequently use the same dose adjustment strategy, more aggressive than historical dosing strategies to optimize clinical response (See Table). The primary endpoint is clinical response defined by %HbF measured 6 months after starting HU. As recruitment for the HOPS Trial is nearly complete but ongoing, we do not report primary or clinical results here. Here we demonstrate the feasibility of a PK-guided dosing across multiple centers and present data related to HU dosing and laboratory toxicity to demonstrate the safety of higher starting doses for young children with SCA. Results: As of August 1, 2022, there have been 95, of a planned 104, participants enrolled in the HOPS Trial. The median age of enrollment was 10 months with most (72%) participants ≤ 2 years of age. Despite the young starting age, most participants had at least one complication or hospitalization related to SCA prior to starting HU, and 84% demonstrated significant hemolytic anemia, evidenced by a hemoglobin < 10.5 g/dL with absolute reticulocyte count > 150 x109/L prior to initiation of HU. The mean starting absolute neutrophil count (ANC) across this entire, mostly young cohort was relatively low (3.5 ± 2.2 x 109/L) with 52% of participants having a baseline ANC < 3.0x109/L and 24% with an ANC < 1.5 x 109/L prior to hydroxyurea initiation. The starting doses were higher, as expected, for the PK-guided dosing arm (28.2 ± 5.2 mg/kg/day) compared to the weight-based dosing arm (20.2 ± 0.6 mg/kg/day). Despite high starting doses, there was no evidence of increased hematologic toxicity through the first 12 months of hydroxyurea therapy in the PK-guided dosing arm. To date, there have been a total of 24 dose holds in 18 participants due to hematologic toxicity, most commonly transient incidental neutropenia, with no differences between starting dose (i.e. higher or lower PK-guided dose) or study arm assignment (10 in PK-guided arm, 8 in weight-based arm). ANC was lower in the PK-guided dosing arm at month 6 compared to the weight-based dosing arm (2.2 ± 1.4 vs. 3.2 ± 1.9) but not in an unsafe range. Conclusions: These preliminary results from the HOPS Trial demonstrate that starting doses of hydroxyurea as high as 25-30 mg/kg/day are safe and not associated with an increased risk of clinically significant hematologic toxicity in young children with SCA, even among young children with relatively low ANCs. Complete results of the HOPS trial are forthcoming. Which will formally evaluate the clinical benefits of PK-guided initial dosing compared to the traditional 20 mg/kg starting dose strategy. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Effects of Hydroxyurea Treatment on Haemolysis in Patients with Sickle Cell Disease at Muhimbili National Hospital, Tanzania

Tanzania is one of the countries with a high burden of sickle cell disease (SCD). Haemolytic anaemia is a clinical feature of SCD, and has been linked to major complications leading to morbidity and mortality. Treatment with hydroxyurea (HU) has shown to induce foetal haemoglobin (HbF) which in turn decreases haemolysis in patients. This study aimed to investigate the effects of HU on haemolysis in SCD patients attending Muhimbili National Hospital, Tanzania by comparing their haemolytic parameters before and after therapy. Patients meeting the criteria were initiated on HU therapy for 3 months. Two haemolytic biomarkers: unconjugated plasma bilirubin levels and absolute reticulocyte counts were measured from patients’ blood samples at baseline and after 3 months of HU therapy and compared. Both absolute reticulocyte counts and indirect plasma bilirubin levels significantly declined after HU therapy. Median (IQR) plasma unconjugated bilirubin levels dropped significantly from 20.3 (12.7–34.4) μmol/L to 14.5 (9.6–24.1) μmol/L (p &lt; 0.001) and mean (SD) absolute reticulocyte counts dropped significantly from 0.29 (0.1) x 109/L to 0.17 (0.1) x 109/L (p &lt; 0.001) after therapy, thus, a decline in both haemolytic biomarkers after treatment was observed. This study found a potential for use of HU therapy in managing SCD patients in our settings evidenced by improvements in their haemolytic parameters. Clinical trials with a lager sample size conducted for a longer time period would be beneficial in guiding towards the inclusion of HU in treatment protocols for the Tanzanian population.&#x0D; Keywords: Sickle cell disease; hydroxyurea; haemolysis; foetal haemoglobin&#x0D;

Impact of hydroxyurea therapy on clinicohematological parameters in children with sickle cell anemia

Background: Sickle cell anemia (SCA) is an autosomal recessive disorder associated with high morbidity and mortality in children. Hydroxyurea (HU) has shown to decrease the frequency of vaso-occlusive crisis, hospitalization, and blood transfusion in SCA patients. Objective: The objective of the study was to evaluate the efficacy of HU on clinical and hematological parameters in pediatric patients with SCA. Materials and Methods: A prospective analytic study was conducted among 49 children aged between 5 and 14 years, diagnosed with SCA visiting the outpatient department at a tertiary care center of Central India for over a period of 13 months. Children enrolled in the study were given HU and they were followed at every 2-month for 6 months. Clinical and laboratory parameters of the study population were recorded and analyzed. With nine children lost to follow up, the final analysis was carried in only 40 patients. Results: Most of the children (60%) belonged to the age group of 5–9 years and male predominance (70%) was observed in the study. Clinical parameters including number of hospitalization, vaso-occlusive crisis, and frequency of blood transfusion decreased significantly (p&lt;0.01). After 6 months of HU therapy, there was increase in hemoglobin levels (p=0.002), decrease in total leukocyte count (p=0.001), and platelet count was observed (p=0.283). Improvement in the serum glutamic pyruvic transaminase and serum creatinine (p&lt;0.01), serum bilirubin, blood urea, and serum glutamic-oxaloacetic transaminase (p&gt;0.05) was observed. No adverse reactions were noticed during this study period. Conclusion: HU is an effective drug and can be safely used for the treatment in SCA.

Rapid and Automated Quantitation of Dense Red Blood Cells: A Robust Biomarker of Therapeutic Response to Early Initiation of Hydroxyurea in Young Children with Sickle Cell Anemia

Introduction: Hydroxyurea has well-described clinical and laboratory benefits in sickle cell anemia (SCA). Traditionally, hemoglobin concentration (Hb) and fetal hemoglobin (HbF) are used to assess treatment response, but these aggregate parameters do not fully capture the range of erythrocyte abnormalities in SCA. Dense red blood cells (DRBCs) are defined as RBCs with density &amp;gt;1.11 g/mL as measured by density-gradient fractionation methods, which are tedious and require technical expertise. This subpopulation of dehydrated RBCs has been associated with increased SCA severity but has not been extensively studied in children. Here we describe the utility of rapid, automated DRBC quantitation and show that the percent of DRBCs (%DRBCs) is a robust biomarker of hydroxyurea response in children with SCA. Methods: The Therapeutic Response Evaluation and Adherence Trial (TREAT, NCT02286154) was a single-center prospective study that demonstrated individualized, pharmacokinetic (PK)-guided hydroxyurea dosing in young patients (mean age 12.1 months at initiation) results in robust and sustained HbF levels &amp;gt;30-40% for most adherent patients. The longitudinal follow-up phase of TREAT aims to comprehensively evaluate hematologic parameters and organ function to demonstrate the long-term benefits of this treatment strategy. During clinic visits (every 3-6 months), TREAT participants had complete blood counts (CBCs) with the ADVIA® 2120i system. This automated analyzer quantifies hyperchromic RBCs within seconds by directly measuring cell hemoglobin concentration, where DRBCs are known to correspond to RBCs with a measured MCHC &amp;gt;41 g/dL. Data were analyzed at baseline and after at least 6 months of hydroxyurea therapy (M≥6). α- and β-globin genotypes were determined for all patients. Results: Thirty-three TREAT participants had ADVIA data available for analysis (Table). All had homozygous SCA except one with sickle-β0-thalasemia; 17 (51.5%) were male. The median age at hydroxyurea initiation was 10.3 months (mean 26.1 months; range 6 months - 17 years). The median duration of hydroxyurea therapy was 27.7 months (mean 31.5). At baseline, median %DRBCs was 2.1%. Baseline %DRBCs were directly correlated with age at initiation of hydroxyurea (p=0.022) and inversely correlated with baseline HbF (p=0.001). After initiation of hydroxyurea (M≥6), there was a 47.6% reduction in %DRBCs (p=0.001). Median %DRBCs at M≥6 was directly correlated with absolute reticulocyte (ARC) (p=0.002), absolute neutrophil (ANC) (p=0.003) and platelet counts (p&amp;lt;0.001) and inversely correlated with Hb (p=0.013) and hematocrit (Hct) (p=0.019), consistent with the laboratory benefits of hydroxyurea. In bivariate analysis, the change in %DRBCs from baseline was directly correlated with baseline %DRBCs (p&amp;lt;0.001) and inversely correlated with baseline HbF (p=0.005). In multivariate analysis, baseline %DRBCs was the only biologic parameter that independently predicted %DRBC change (β=-0.86, p&amp;lt;0.001, model r2=0.91; Figure). Even when baseline %DRBCs were only mildly increased (as low as 1.5%), participants had a marked decline in %DRBC with hydroxyurea. When baseline %DRBCs were very low at baseline (&amp;lt;1.5%), they remained low after treatment. Of note, there was no correlation between %DRBC change and α-thalassemia status. Conclusions: DRBCs can be rapidly quantified without the tedium of classical density-gradient fractionation methods using the automated ADVIA 2120i hematology analyzer, which directly measures hyperchromic RBCs. These data from TREAT demonstrate the feasibility of serial %DRBC measurements in clinical trials and clinical practice. TREAT participants had low baseline DRBCs compared to untreated adult SCA patients (reported mean ≈12%), reflecting the young age of these patients. Nevertheless, there was a significant decline in %DRBCs with treatment that correlated strongly with the known laboratory benefits of hydroxyurea. In conclusion, automated DRBC measurements are a robust biomarker that can be incorporated in a panel of laboratory measurements of response to hydroxyurea (and severity of SCA). A larger, multicenter study of PK-guided hydroxyurea therapy (HOPS, NCT03789591) is currently underway in 11 US sickle cell centers and will provide generalizable data on DRBC responses with optimal hydroxyurea therapy. Disclosures Malik: Aruvant Sciences, Forma Therapeutics, Inc.: Consultancy; Aruvant Sciences, CSL Behring: Patents &amp; Royalties. Kalfa:Agios Pharmaceuticals, Inc: Consultancy, Research Funding; Forma Therapeutics, Inc: Research Funding.

Hydroxyurea to Reduce Stroke Risk in Tanzanian Children with Sickle Cell Anemia

Introduction: Sickle cell anemia (SCA) is highly prevalent in sub-Saharan Africa with &amp;gt;300,000 annual births, and substantial morbidity and mortality due to limited resources. The burden of stroke in this population is of particular concern, given the devastating clinical and neurocognitive sequelae of these events. Hydroxyurea, a potent disease modifying therapy for SCA, is safe and feasible for low-resource and malarial endemic countries within sub-Saharan Africa and when used at maximum tolerated dose (MTD), decreases the incidence of acute painful vaso-occlusive events, infections, malaria, transfusions, hospitalizations, and death. Whether hydroxyurea can prevent primary stroke in SCA within Africa has not yet been determined, due in part to lack of stroke screening programs using transcranial Doppler (TCD) ultrasonography. If effective, hydroxyurea would have even more therapeutic benefits for children with SCA, particularly in settings where blood is not available, affordable, or safe. We designed the Stroke Prevention with Hydroxyurea Enabled through Research and Education (SPHERE) trial to determine the stroke risk among Tanzanian children using TCD screening and to investigate the effects of hydroxyurea to reduce that risk. Methods: The SPHERE trial (NCT03948867) is a single center prospective phase 2 open-label screening and treatment pilot study at Bugando Medical Centre, a teaching and referral hospital in Mwanza, Tanzania. Children 2-16 years old with SCA consented to TCD screening by locally trained and certified examiners; recent febrile illness, red cell transfusion, or hospitalization were temporary exclusions. Study participants with maximum Time-Averaged Mean Velocity (TAMV) on TCD exam categorized as conditional (170-199 cm/sec) or abnormal (≥200 cm/sec) are offered hydroxyurea with escalation to MTD, while those with normal TCD screening exams will be rescreened annually. Hydroxyurea is initiated at ~20 mg/kg/day using 500 mg capsules and a weekly dosing calculator, then escalated every 8 weeks by 5 mg/kg/day up to 35 mg/kg/day. Children on hydroxyurea are seen monthly during dose escalation and every 3 months after reaching MTD. The primary endpoint is change in TCD velocity after 12 months of hydroxyurea therapy. Secondary endpoints include changes in splenic volume and filtrative function; change in renal function; incidence of infection, especially malaria; hydroxyurea pharmacokinetics; and genetic modifiers of disease including pharmacogenomics. Results: From April 2019 to April 2020, a total of 202 children underwent TCD screening, exceeding the projected enrollment pace and goal (Figure). The average age (mean ± SD) at enrollment was 6.8 ± 3.5 years, and 53% were female. A majority had previous dactylitis (75%), painful vaso-occlusive episode (93%), blood transfusion (68%), and malaria (89%). Recurrent hospitalization was common with 30% having &amp;gt;5 previous hospitalizations. Only 4% had previously used hydroxyurea. Baseline labs included hemoglobin = 7.8 ± 1.3 g/dL, HbF = 9.3 ± 5.4 %, and ANC = 5.5 ± 2.4 x 109/L. Baseline assessment revealed a palpable spleen in 46 children (23%), and most of these (29) were ≥5 cm below the costal margin. Abdominal ultrasonography documented splenic tissue in 91% of children with an average volume of 101 ± 123 mL (range 8-1045). TCD examinations were performed in all children at enrollment with average TAMV of 148 ± 27 cm/sec [median 144, IQR 130-169 cm/sec] with 76% normal, 21% conditional, 2% abnormal, and 1% inadequate exams. Of 47 children eligible for hydroxyurea for elevated TCD velocities, 45 successfully initiated treatment, while 1 lived too far away for regular visits, and 1 had low blood counts from acute splenic sequestration and died before initiating study treatment. Conclusion: Children with SCA in Tanzania have a high risk for primary stroke. Identification of elevated TCD velocities through screening by local trained certified examiners, coupled with initiation of hydroxyurea treatment with dose escalation to MTD, offers a feasible and affordable means by which to lower TCD velocities and reduce primary stroke risk. Now fully enrolled, SPHERE has built local clinical capacity, research infrastructure and high-quality TCD screening, and will prospectively determine the benefits of hydroxyurea for stroke prevention, as a prelude for expanding hydroxyurea access for children with SCA in Tanzania. Figure Disclosures No relevant conflicts of interest to declare.

Effects of hydroxyurea on blood rheology in sickle cell anemia: A two-years follow-up study.

The aim of the present study was to test the effects of hydroxyurea (HU) therapy on clinical, hematological and hemorheological parameters in adult patients with sickle cell anemia (SCA). Hematological and hemorheological parameters were measured in 28 SCA patients before HU therapy (i.e., baseline) and at 6, 12 and 24 months of treatment. RBC deformability was determined by ektacytometry at 30 Pa. RBC aggregation properties were investigated by light-backscatter method. Blood viscosity was measured at 225 s-1 by a cone-plate viscometer. The rates of vaso-occlusive crises and acute chest syndrome were lower at 1 and 2 years of HU therapy compared to baseline. The proportion of patients with leg ulcers tended to decrease after 2 years of treatment. Hemoglobin oxygen saturation improved with HU therapy. HU therapy induced a decrease of platelet and white blood cell counts and a rise in fetal hemoglobin level and mean cell volume. While hemoglobin concentrations increased under HU, blood viscosity remained unchanged all along the study. RBC deformability increased over baseline values at 6 months of HU therapy and continued to rise until the end of the follow-up period. In conclusion, the improvement in RBC deformability probably compensates the increase of hemoglobin on blood viscosity and participates to the improvement of the clinical status of patients.

Hydroxyurea treatment effect on children with sickle cell disease and obstructive sleep apnea

While hydroxyurea is the mainstay of treatment for many of the comorbidities associated with sickle cell disease, its effect on obstructive sleep apnea has not been fully investigated. The purpose of this project is to help characterize the effects of hydroxyurea on obstructive sleep apnea in children with sickle cell disease and determine its therapeutic role in the condition. Chart review was conducted on two pediatric patients with sickle cell disease who experienced resolution of obstructive sleep apnea following hydroxyurea administration. After undergoing approximately 11months of hydroxyurea therapy, sleep apnea symptoms improved and obstructive sleep apnea resolution was confirmed by repeat polysomnography in both cases. This resolution was largely secondary to a reduction in the obstructive component of the apnea hypopnea index, highlighting a previously unreported association. As adenotonsillectomy is associated with significant risks in patients with sickle cell disease, it appears reasonable to consider a period of observation for improvement of obstructive sleep apnea following hydroxyurea administration rather than directly proceeding with surgery.

Prognostic Factors for Hospitalization of Children with Sickle Cell Anemia Treated with Hydroxyurea at Maximum Tolerated Dose

Background: Hydroxyurea (HU) is recommended to be offered to children with sickle cell anemia (SCA; HbSS and HbSβ0 thalassemia) beginning at 9 months of age (Yawn, JAMA 2014). Intensifying HU to a maximum tolerated dose (MTD) provides fetal hemoglobin (HbF) levels of >20% (Ware, Blood 2010). Yet, children treated with HU at MTD still experience hospitalizations due to SCA-related complications (Nottage, PLoS One 2013). The ability to identify children at high risk of experiencing SCA-related complications while on HU would enhance clinical management and facilitate performance of clinical trials of novel agents. Our objective was to identify risk factors associated with hospitalization and to develop a prediction model for hospitalization of children treated with HU at MTD.Methods: The Hydroxyurea Study of Long-Term Effects (HUSTLE) is a prospective observational study (NCT00305175) designed to describe the clinical effects of HU in children with SCA. We have analyzed children who initiated HU per protocol and whose dose was escalated to MTD. Laboratory and clinical data were abstracted at baseline and at 9-12 months after enrollment. The first laboratory values of each interval were considered representative of the period. The primary outcome measure was hospitalization. After a multivariate regression logistic model identified risk factors for hospitalization based on a stepwise selection strategy, a smoothed receiver-operating-characteristic (ROC) curve was generated to predict hospitalization for the composite model and for each individual risk factor using the method of maximum-likelihood fitting of univariate distriubutions. Atlhough HbF was not identified in regression analysis among risk factors, because of its known effects as a disease modifier, it was inserted into the composite model. A prediction model was then generated for the identified risk factors utilizing optimal cutoff values defined by the maximum Youden method.Results: 151 children (mean [SD] age, 8.3 [5.0] years) were analyzed. HU resulted in higher HbF levels (22.6% [9.1] versus 10.1% [7.1]; p<0.0001), lower absolute neutrophil counts (4000/mm3 [2600] versus 7000/mm3 [3800]; p<0.0001), and fewer hospitalizations (7.8% [10/128] versus 28.9% [39/128]; p<0.0001) after 9-12 months compared to baseline.Children hospitalized after 9-12 months of therapy had similar HbF levels compared to those not hospitalized (OR 0.98 [95% CI: 0.9-1.1]; p=0.5), but higher total bilirubin (BiliT) (OR 1.3 [95% CI: 1.0-1.6]; p=0.03), blood urea nitrogen (BUN) (OR 1.3 [95% CI: 1.1-1.7]; p=0.19), and lactate dehydrogenase (LDH) (OR 1.01 [95% CI: 1.002-1.010]; p=0.006) levels. A ROC curve including insertion of HbF showed an area under the curve (AUC) of 0.90 (Figure 1). Optimal cutoffs for risk factors were: BiliT 1.05 mg/dL, BUN 8.5 mg/dL, and LDH 473 units/L. The probability of hospitalization varied in relation to identified risk factors (Table 1).Table 1Predicted probability of hospitalization after 9-12 months of HU at MTD# of risk factorsBiliTHbFBUNLDHProbability of≥1.05(mg/dL)≤20 (%)≥8.5(mg/dL)≥473(units/L)Hospitalization (%)0NoNoNoNo<11YesNoNoNo<1NoYesNoNo1.3NoNoYesNo5.8NoNoNoYes192YesYesNoNo<1YesNoYesNo<1YesNoNoYes2.2NoYesYesNo10NoYesNoYes29NoNoYesYes653YesYesYesNo1.1YesYesNoYes3.8YesNoYesYes15NoYesYesYes774YesYesYesYes25LDH, lactate dehydrogenase; BiliT, total bilirubin; BUN, blood urea nitrogenDiscussion: In this pediatric cohort, HU therapy at MTD produced a robust laboratory response with most children having HbF >20% after 9-12 months. At such high levels of HbF, few children experienced a hospitalization due to its protective effects; however, we identified three laboratory parameters (LDH, BiliT, and BUN) that were predictive risk factors for children who continued to be hospitalized despite high levels of HbF. After 9-12 months of HU therapy at MTD the probability of hospitalization ranged from <1% to 65% for children with HbF of less than <20% and <1% to 77% in children with HbF of >20%. This model may help identify children at risk for complications of SCA while being treated with HU at MTD. [Display omitted] DisclosuresEstepp:Eli Lilly and Company: Research Funding; Daiichi Sankyo: Research Funding. Off Label Use: Off label use of hydroxyurea in children with sickle cell anemia.

Biological Parameters Predictive Of Percent Dense Red Blood Cell Decrease Under Hydroxyurea Therapy

IntroductionDehydrated, dense red blood cells (DRBC), a subpopulation of sickle cells, are characterized by density >1.112; their increased mean corpuscular hemoglobin concentration (MCHC) leads to hemoglobin S (HbS) polymerization. The %DRBC is the biological parameter most strongly associated with some sickle-cell–disease (SCD) chronic organ damage, e.g., renal dysfunction, leg ulcers and priapism, also called hemolytic subphenotypes (Bartolucci et al. Blood 2012; Kato et al. Blood Rev 2007). Proven hydroxyurea (HU) efficacy against SCD lowers vaso-occlusive crisis, acute chest syndrome frequencies, and mortality (Charache et al. N Engl J Med 1995). The classical biological parameters indicating HU response are fetal hemoglobin (HbF) and mean corpuscular cell volume (MCV) increases (Steinberg et al. Blood 1997). However, we previously found decreased %DRBC in 33 patients after 6 months of HU (Bartolucci et al. Blood 2012) .We analyzed baseline biological parameters to identify those predictive of %DRBC decline under HU. Patients and methodsWe conducted a monocenter, prospective, longitudinal study on SCD patients undergoing HU therapy. Data were collected at baseline (day 0) and after 6 months of HU. Inclusion criteria were: SS and S-β0 thalassemia patients, age >18 years. Non-inclusion criteria were pregnancy, chronic blood transfusion and refused consent. Biological parameters determined were: %DRBC assessed with the phthalate density-distribution technique, D50 (defined as the density at which [(height of cells below phthalate index/sum of those above and below that index) = 0.5]), white blood-cell count (WBC count), MCV, MCHC, mean corpuscular hemoglobin content (MCH), total Hb, reticulocytes (RET), %HbF, platelet count, total bilirubin, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase. Results are expressed as means ± SD, numbers or %, as appropriate. Quantitative parameters were compared between groups with Student's paired t-test. Correlations were established with Pearson's correlation coefficient. Multiple linear regressions were used to explore models that better predicted DRBC variation under HU. The final models included the variables that remained significantly associated with %DRBC decline after adjustment for the other variables in the models. R-squared (r2) were used as measures of variance explained by the models. P < 0.05 defined significance. This study was approved by the local Institutional Review Board. Results and DiscussionFifty-nine patients, mean age 35 ± 9 years, were included. Their %DRBC fell significantly by 40.7% after 6 months of HU therapy (P = 0.0003) from 10.1 ± 8% to 6 ± 4%. The %HbF rose from 7.2 ± 4% to 17.3 ± 8%. Our univariate analysis identified variables significantly correlated with %DRBC (Table). Multivariate analysis retained a significantly positive correlation between %DRBC decreases under HU and the pretreatment %DRBC on day 0. This statistical model accounted for 71.9% of the variability of %DRBC decline under HU. Pertinently, no correlation was found between %HbF and %DRBC changes, suggesting different mechanisms of action. ConclusionOur results confirmed the HU impact on %DRBC decrease, suggesting new indications to prevent or treat SCD complications associated with high %DRBC. They also showed that the major parameter predictive of DRBC decline under HU was the baseline %DRBC. %HbF and %DRBC changes under HU were not correlated. Prospective studies are needed to analyze the therapeutic effects of HU on chronic complications. Disclosures:No relevant conflicts of interest to declare.

Melanonychia and skin hyperpigmentation with hydroxyurea therapy

Sir, Hydroxyurea or hydroxycarbamide is an antineoplastic drug used in myeloproliferative disorders (chronic myeloid leukemia, polycythemia vera, and essential thrombocythemia), psoriasis (second-line systemic agent), and AIDS (antiretroviral properties potentiate the activity of the nucleoside reverse transcriptase inhibitor didanosine). The adverse mucocutaneous effects include hyperpigmentation, alopecia, leg ulcers, and lichenoid eruptions. We report a patient who developed hyperpigmentation of the skin and nails 10 weeks after the start of hydroxyurea therapy. A 31-year-old man presented to the dermatology outpatient department with gradually progressive pigmentation of hands, legs, and all finger-nails since 1 month. The pigmentation started from proximal parts of nail plates and progressed distally. The patient was receiving hydroxyurea for chronic myeloid leukemia in a dose of 1 g/day for last three and half months. On examination, diffuse uniform hyperpigmentation was noted on all 10 finger-nails involving approximately half to two-thirds of the nail plates [Figure 1]. Hyperpigmentation was seen on hands and legs with sparing of toe nails. All routine investigations were normal except for mild anemia (hemoglobin 12.2 g/dL and hematocrit 43.8%). All necessary investigations were carried out to eliminate Vitamin B-12 deficiency, hyperbilirubinemia, Addison's disease, Cushing's syndrome, hyperthyroidism, hemosiderosis, scleroderma, and HIV. At the time of presentation, he was not taking any other drug that could have caused the nail hyperpigmentation. We considered temporary discontinuation of the drug and restart it to observe the outcome. However, the patient was lost to follow-up. According to causality assessment by Naranjo's algorithm, this event could be defined as “probable”.[1] Figure 1 Hyperpigmentation involving hands and all 10 finger-nails; involving proximal half to two-third of the nail plates. Nail grows at a rate of 0.1 mm/day. It takes approximately 100–120 days for the whole nail to grow. Finger nails grow faster than the toe nails. Nail changes as a result of antineoplastic drugs are asymptomatic and entirely reversible within few months after withdrawal of the offending agents. The most frequent presentation of chromonychia (various patterns of nail discoloration) induced by antineoplastic drugs is melanonychia, a dark pigmentation of nails seen in diffuse, transverse, or longitudinal band patterns. It may co-exist with diffuse pigmentation of skin, also known as melanoderma. The mechanism of hydroxyurea-induced melanonychia is still unknown; the potential causes include toxicity affecting the nail bed or nail matrix, focal stimulation of nail-matrix, melanocytes, and photosensitization. The differential diagnosis includes subungual melanoma, pigmented squamous-cell carcinoma, subungual hematoma, nevus, and hyperpigmentation owing to other drugs, including cyclophosphamide, doxorubicin, minocycline, and zidovudine. Aste et al. reported nail hyperpigmentation in nine patients appearing between 6 and 24 months of hydroxyurea-therapy, the commonest presentation being longitudinal melanonychia.[2] Longitudinal melanonychia, diffuse melanonychia affecting all nails and hyperpigmentation of the skin were observed in one patient. However in our case, presentation was noted early; within 10 weeks of starting of therapy. There are reports of progressive transverse melanonychia of all 20 nails within 7 weeks of starting hydroxyurea in a patient of thrombocytosis.[3] Gropper et al. and Issaivanan et al. reported melanonychia of all 20 nails with involvement of all three mucocutaneous areas (skin, nails, and mucosa) in a 63-year-old black woman and a 10-year-old boy, respectively, within 3 months of therapy.[4,5] A dermatomyositis-like eruption was observed in two reported cases.[6] Jeevankumar et al. reported a rare case of hydroxyurea-induced blue lunula.[7] Sometimes both longitudinal melanonychia and periungual hyperpigmentation may be observed together.[8] This presentation may be confused with Hutchinson's sign in malignant melanoma. Ideally, all cases of melanonychia should be distinguished from subungual malignant melanoma. We, therefore, report this interesting case where progressive diffuse melanonychia was observed in all 10 finger-nails with noticeable sparing of the toe nails, associated with pigmentation of hands and legs 10 weeks after starting hydroxyurea therapy.

Hydroxyurea Effect On Marked Splenomegaly Associated with Primary Myelofibrosis: Response Rates and Correlation with JAK2V617F Allele Burden.

Abstract 4971 BackgroundMarked splenomegaly severely compromises quality of life in primary myelofibrosis (PMF). Preliminary results from the use of small molecule JAK2 inhibitors suggest prominent activity in reducing spleen size. In order to put such salutary effect of investigational drug therapy in context, it is important to determine the value of conventional therapy in this regard. MethodsStudy population was selected from the Mayo Clinic PMF database and consisted of patients treated with hydroxyurea (HU) as first-line therapy for symptomatic, marked splenomegaly (palpable at >10 cm below the left costal margin) and in whom follow-up information was available to assess response. Palpable spleen size measurements were recorded before and after 3, 6 and 12 months of HU therapy. Spleen response was defined as minimal (< 25% reduction), minor (25-50%), or major (>50%). Standard statistical procedures were used to correlate spleen response with other clinical and laboratory parameters, including cytogenetic and JAK2V617F mutational status. Results46 consecutive patients (median age, 62 years; range 38-75; 30 males) met the above stipulated eligibility criteria for study inclusion. Pre-treatment IPSS risk categories were low, intermediate-1 (int-1), int-2 and high in 4, 13, 10 and 19 patients, respectively; 7 patients were transfusion-dependent. Quantitative JAK2V617F and pre-treatment cytogenetic information were available in 25 and 36 patients, respectively; 15 (60%) patients were positive for JAK2V617F and mutant allele burden was > 50% in 6 patients; 17 (47%) patients carried either favorable (n=5) or unfavorable (n=12) cytogenetic abnormalities.Overall response rate (major and minor) was 35% (16 of 46 patients) and major response rate 17%. Overall response rates were 10%, 67% and 33% in patients with undetectable JAK2V617F or mutant allele burden of < or ≥ 50%, respectively (p=0.04). Overall response rates in patients with normal, favorable and unfavorable karyotype were 32%, 40% and 33%, respectively (p=0.9). Response was not affected by age, sex, HU dose or pretreatment status regarding spleen size, IPSS score or transfusion need. ConclusionsThe current study provides background information on the value of conventional chemotherapy for controlling PMF-associated marked splenomegaly. The study also suggests a positive effect of JAK2V617F on treatment response to HU, a detail that needs to be considered when assessing the corresponding effect from a JAK2 inhibitor therapy. DisclosuresOff Label Use: Hydroxyurea use in myelofibrosis.

Familial Essential Thrombocythemia in a Child with Elevated Thrombopoietin Concentrations and Skeletal Anomalies.

We describe a 2-year-old child with an incidental finding of persistent elevated platelet count. The platelet count at the time of referral was 900 × 109/L. His physical examination revealed bony abnormalities of the right upper extremity, and hand. (Photo1) X-Ray of the hand revealed amputation of the fingers of the right hand with rudimentary metacarpal bones, and evidence of shorter radius and ulna of the of the left forearm when compared to the right. The physical examination was otherwise normal with the exception of moderate splenomegaly. Further workup revealed normal iron stores, and no inflammatory process which could explain the thrombocytosis. Chromosomal breakage and rearrangements studies were normal and confirmed a normal male karyotype. A bone marrow aspirate and biopsy revealed megakaryocytic hyperplasia with many binucleated and trinucleated megakaryocytes. (Photo 2) The erythroid and myeloid series were well represented and of normal morphology. Flow cytometry for ALL specific and CMLspecific markers were normal. The platelet count reached 2,800 × 109/L, and serum thrombopoietin level was obtained, which returned 2119.8 pg/ml. The patient was placed on hydroxyurea and aspirin 81mg/day, and reduction in the platelet count occurred. After six months of hydroxyurea therapy the platelet count rose again to pretreatment levels. Hydroxyurea was discontinued and anagrelide started with moderate platelet reduction. Family members were also evaluated. The siblings all had normal platelet counts but the mother had an elevated platelet count 900 × 10 9/L. The bone marrow aspirate of the childs mother was also consistent with ET. The JAK2 kinase mutation was not found in the mother or the child. The childs mother was also found to have an elevated thrombopoietin level of 475.6 pg/ml and was started on hydroxyurea.No connection has been made between our patients congenital anomalies and the thrombocytosis. To our knowledge there have been no other reports of such features in either adult or pediatric patients with ET. Because this childs mother was also subsequently diagnosed with ET, familial ET is a more likely diagnosis. The diagnosis of familial ET is further supported by the elevated TPO concentration in our patient. Sporadic cases of familial ET with elevated thrombopoietin concentrations have been reported. Although ET has been reported in patients as young a 6 weeks, our case is different than other reported pediatric cases of ET because of not only the elevated TPO but the associated skeletal anomalies of our patient. To date neither the child or the mother has suffered any thrombohemorrhagic events, which have been reported to occur at rates varying from 20% to 40%. The mother and child are being followed prospectfully with serial blood counts, serum TPO concentrations. [Display omitted] [Display omitted]

Elevated Glomerular Filtration Rate (GFR) in Young Patients with Sickle Cell Anemia.

Nephropathy is a well-recognized complication of sickle cell anemia (SCA) that is associated with considerable morbidity and mortality. Sickle nephropathy begins early in life, with glomerular damage characterized by hyperfiltration and glomerulomegaly, as well as tubular damage characterized by hyposthenuria. School-aged children can develop proteinuria and one-third of patients will eventually develop chronic renal failure as adults. Among the earliest markers of sickle nephropathy is glomerular hyperfiltration, typically measured as an elevated glomerular filtration rate (GFR). To date, however, no formal measurements of GFR have been published in young children with SCA, and its feasibility and interpretation in this age group have not been demonstrated. As part of a prospective, single-institution, IRB-approved open-label protocol using hydroxyurea in toddlers with SCA, the pre-treatment GFR was measured using plasma clearance of 99-Tc DTPA. The goal of this procedure was to determine the onset of hyperfiltration among young children with SCA, to identify risk factors associated with its onset, and to investigate the potential benefit of hydroxyurea in improving or preserving renal function. After intravenous injection of the DTPA radiotracer, 3–5 mL aliquots of venous blood were removed at 1 and 3 hours post-injection and analyzed for plasma radioactivity. Because DTPA is filtered at the glomerulus without substantial metabolism, secretion, or reabsorption, the plasma clearance allows an accurate and precise GFR measurement. The GFR was also estimated using the Schwartz equation, where GFR = height (cm) x k/serum creatinine, with k=0.55 for children between ages 1 and 12 years. A total of 13 children with HbSS (3 females, 10 males) were enrolled in this study, none of whom had laboratory evidence of renal disease at the time of evaluation. One child could not complete the DTPA study due to inadequate venous access. For the remaining 12 children, baseline GFR measurements were performed at age 3.0 ± 0.8 years (range 1.7 to 4.4 years) without complications. The average GFR measurement (mean ± SD) by DTPA clearance was 140.3 ± 20 mL/min/1.73m2, median 133 mL/min/1.73m2, range 117.9 to 172.7 mL/min/1.73m2 (normal 100 ± 20 mL/min/1.73m2). The baseline DTPA GFR measurement was elevated above 150 mL/min/1.73m2 in 5 of the 12 children, including 4 of 7 over age 3 years, although there was no signfiicant correlation between GFR and age or fetal hemoglobin. GFR estimates by the Schwartz equation were modestly correlated with the DTPA GFR measurements (R2 = 0.32, p = 0.055) but were typically slightly higher than the corresponding DTPA measurements. Three children who completed 24 months of hydroxyurea therapy had post-treatment DTPA clearance studies that revealed stable GFR measurements (average increase = 5.6 mL/min/1.73m2). These results illustrate that GFR measurement by DTPA clearance can be performed without difficulty in young children with SCA, requiring only peripheral intravenous access. Glomerular hyperfiltration as a manifestation of renal damage begins early in life for children with SCA, with elevated GFR values observed in the toddler age range. The Schwartz equation provides an estimate of GFR but probably cannot be used in lieu of the DTPA clearance study. Treatment with hydroxyurea may preserve renal function by abrogating further GFR hyperfiltration.

The Effect of Hydroxyurea on the Coagulation System in Sickle Cell Anemia and β-Thalassemia Intermedia Patients: A Preliminary Study

Hydroxyurea (HU) has been shown to reduce the frequency of vaso-occlusive manifestations in both adults and children with sickle cell disease (SCD), and the induction of hemoglobin F (HbF) is thought to be the underlying mechanism responsible for clinical improvement in some patients. However, there exists no good correlation between the amount of HbF increase and clinical response. Recent studies suggest that increased activity of the coagulation system may be important in the pathogenesis of vascular occlusion in sickle cell disease. To analyze the effect of HU on the coagulation system in children, the authors studied the levels of some coagulation factors and natural inhibitors. Eleven children who had been treated with HU because of SCD (5 patients), sickle- g -thalassemia (3 patients), and g -thalassemia intermedia (3 patients) were enrolled in the study. Levels of the coagulation factors II, V, VII, VIII, IX, X, XI, and XII, and of protein C and protein S, prothrombin times, activated partial thromboplastine times, thrombin times, and reptilase times were measured before the treatment and at the 5th or 6th months of HU therapy when the patients were in a steady-state condition. There was a decrease in all of the coagulation factors except for FIX and FXII and in inhibitors such as protein C and protein S. However, statistically significant decreases were observed only in factor VIII and protein C levels. The rates of decrease were 54.8 and 12.5% ( p = .015 and p = .018) in FVIII and protein C, respectively. This result shows that HU has significant effects on the coagulation and natural inhibitory systems.

EFFECT OF HYDROXYUREA IN SICKLE CELL ANEMIA: A Clinical Trial in Children and Teenagers with Severe Sickle Cell Anemia and Sickle Cell beta-Thalassemia

This study evaluated the efficacy of hydroxyurea treatment in the prevention of vaso-occlusive crises among children and teenagers with severe sickle cell anemia and sickle cell beta-thalassemia. Nineteen children and young adults with severe sickle cell disease were enrolled to the hydroxyurea treatment trial. The incidence of vaso-occlusive crises, acute chest syndrome, hemolytic crises, splenic sequestration episodes, blood transfusions,and hospital days in the 2 years before hydroxyurea (HU) treatment were compared with the same parameters in the first 2 years of treatment. The patients received a mean dose of 21.3 mg/kg/day daily and were treated during a mean period of 40.3 14 months (range 20 to 68 months). Significant increases were observed after 1 month in the Hgb, MCV, MCH, and MCHC levels and were more notable after 3 months. The increase in the Hgb F level became important after 3 months of HU therapy and was highly significant (p < .001) beyond 6 months. No differences were observed in the R DW, reticulocyte count, Hgb S, and Hgb A2 . Severe neutropenia was observed in one case. A decrease in the frequency of vaso-occlusive crises, acute chest syndrome, hemolytic crises, blood transfusions, and days spent in the hospital was demonstrated during the HU treatment period compared to the same period before. The clinical and laboratory response to HU was dramatic in severely affected sickle cell anemia (SCA) patients. The response to HU in children and teenagers with severe sickle cell anemia is similar to the response in adults, and no severe adverse effects were observed.