ALBERT

Description: The consequences of sickle cell disease (SCD) include ongoing hematopoietic stress, hemolysis, vascular damage, and effect of chronic therapies, such as blood transfusions and hydroxyurea, on hematopoietic stem and progenitor cell (HSPC) have been poorly characterized. We have quantified the frequencies of nine HSPC populations by flow cytometry in the peripheral blood of pediatric and adult patients, stratified by treatment and control cohorts. We observed broad differences between SCD patients and healthy controls. SCD is associated with 10 to 20-fold increase in CD34dim cells, a two to five-fold increase in CD34bright cells, a depletion in Megakaryocyte-Erythroid Progenitors, and an increase in hematopoietic stem cells, when compared to controls. SCD is also associated with abnormal expression of CD235a as well as high levels CD49f antigen expression. These findings were present to varying degrees in all patients with SCD, including those on chronic therapy and those who were therapy naive. HU treatment appeared to normalize many of these parameters. Chronic stress erythropoiesis and inflammation incited by SCD and HU therapy have long been suspected of causing premature aging of the hematopoietic system, and potentially increasing the risk of hematological malignancies. An important finding of this study was that the observed concentration of CD34bright cells and of all the HSPCs decreased logarithmically with time of treatment with HU. This correlation was independent of age and specific to HU treatment. Although the number of circulating HSPCs is influenced by many parameters, our findings suggest that HU treatment may decrease premature aging and hematologic malignancy risk compared to the other therapeutic modalities in SCD.

Description: The concentration of circulating hematopoietic stem and progenitor cells has not been studied longitudinally. Here, we report that the proportions of Lin-CD34+38- hematopoietic multipotent cells (HMCs) and of Lin-CD34+CD38+ hematopoietic progenitors cells (HPCs) are highly variable between individuals but stable over long periods of time, in both healthy individuals and sickle cell disease (SCD) patients. This suggests that these proportions are regulated by genetic polymorphisms or by epigenetic mechanisms. We also report that in SCD patients treated with hydroxyurea, the proportions of circulating HMCs and HPCs show a strong positive and negative correlation with fetal hemoglobin (HbF) levels, respectively. Titration of 65 cytokines revealed that the plasma concentration of chemokines CCL2, CCL11, CCL17, CCL24, CCL27, and PDGF-BB were highly correlated with the proportion of HMCs and HPCs and that a subset of these cytokines were also correlated with HbF levels. A linear model based on four of these chemokines could explain 80% of the variability in the proportion of circulating HMCs between individuals. The proportion of circulating HMCs and HPCs and the concentration of these chemokines might therefore become useful biomarkers for HbF response to HU in SCD patients. Such markers might become increasingly clinically relevant, as alternative treatment modalities for SCD are becoming available.

Description: Background Leg ulcerations are a serious and debilitating complication of sickle cell disease (SCD). Patients with SCD and leg ulcers have biomarkers of severe hemolytic anemia, a state associated with low bioavailability of nitric oxide (NO). Therapies directed at restoring NO bioavailability might prove beneficial. We selected topical sodium nitrite for clinical development due to its safety profile and vascular, anti-microbial, antiplatelet, and pro-keratinocyte functions. The nitrite anion is a vasodilator in vivo by generating NO in tissues with low oxygen tension and pH, conditions that are likely present in chronic wounds. Data from our successful phase 1 study showed improved regional blood flow, decreased ulcer pain, and appeared to improve ulcer healing. The dosing data informed the concentration of active ingredient to be used and suggested sodium nitrite efficacy in SCD patients with leg ulcers (Minniti, CP et al, Lancet Haematol 1, e95-e103). Study Design and Methods This is a multicenter, phase 2, prospective, randomized, placebo-controlled study of topical sodium nitrite in patients with SCD and leg ulcers. Primary aim is to determine the safety, tolerability, and effectiveness of twice a week topical application of study ointment for 10 weeks. We hypothesize that sodium nitrite will 1) accelerate wound healing (〉25% improvement over placebo arm); and/or 2) decrease pain at the wound site (〉20% over placebo). Ulcers measured by ImageJ planimetry software to increase accuracy. The secondary aims are to: a) evaluate the effect of hydroxyurea (HU) on leg ulcer healing in combination with topical sodium nitrite or placebo; b) assess changes in ulcer microbiome after application of sodium nitrite or placebo and how these changes may relate to healing; c) evaluate the dermal composition and microvascular structure in the ulcer beds. We plan to enroll 50 adults with all SCD genotypes and leg ulcers not individually 〉100 cm2, such that, after an expected 20% dropout, 40 subjects will complete 〉 8 weeks of treatment. Exclusion criteria: use of PDE5 inhibitors, NO, L-arginine, nitroprusside, nitroglycerine; acute bacterial infection; pre-existing methemoglobinemia (〉3.5% on two different occasions); G6PD deficiency. Randomization is stratified by HU use to minimize potential confounding effects on study outcomes. Funded by the Food and Drug Administration (FDA) Division of Orphan Drug Development (# FD-R-0005729); active at two sites (ClinicalTrials.gov NCT02863068). Results We have screened 68 subjects with known history of leg ulcer: 46% were not eligible as the ulcer was closed at the time of screening. Of the 30 eligible, 13 subjects enrolled (12 at Montefiore Medical Center, 1 at the University of Pittsburgh), with 9 subjects randomized. Reasons for screen failure, other than ulcer closed, are depicted in fig 1. Three subjects experienced ulcer decrease 〉25% in the run-in period and did not have ointment application as per protocol. One subject withdrew due to lack of adherence. Therefore the overall dropout rate at this time is 33%, higher than the 20% anticipated. No study ointment SAEs have been noted, AEs have been minor and non-ointment related. Most SAEs have been VOCs, expected in this patient population and wound infections. Discussion As expected, enrollment of subjects with a rare complication of a rare disease is challenging. The recurrent pattern of ulcers in SCD was the reason why the majority of patients were not able to enroll, as the ulcer was closed at the time of screening. We monitor them closely for possible re-opening. Simplification of protocol-related procedures, such as decrease in number of required visits from twice to once a week by packaging dose-specific blister packs that the patient takes home for self-administration of ointment, has facilitated enrollment. Travel to the center is being addressed. A close relationship between the subjects and study team is essential. Co-location of the wound specialist in the sickle cell clinic and training the research nurse for wound care has helped with recruitment. Disclosures Ogu: Vertex Pharmaceuticals: Consultancy. Kato:Novartis, Global Blood Therapeutics: Consultancy, Research Funding; Bayer: Research Funding. Minniti:Doris Duke Foundation: Research Funding.

Description: Background Chronic hemolysis is a hallmark of sickle cell disease (SCD). Intravascular hemolysis in particular is associated with severe vasculopathic complications including pulmonary hypertension (PH) and early mortality. Free heme causes oxidative damage and recently was identified as erythrocyte-derived Danger Associated Molecular Pattern (e-DAMP), associated with endothelial activation and vaso-occlusion in SCD (Belcher et al., Blood. 2014; Ghosh et al., J. Clin. Invest. 2013). Intravascular hemolysis is associated with elevated levels of serum lactate dehydrogenase (LDH). Heme catabolism leads to endogenous carbon monoxide (CO) production by heme oxygenase-1 (HO1), and CO is eliminated in exhaled breath. CO is transported primarily as the conjugate carboxyhemoglobin (HbCO), and end-alveolar CO (EACO) is an accepted proxy marker for its concentration in blood. We evaluated several lab values and ratios that might reflect the relative contribution of intravascular heme release and overall heme processing. Methods We investigated the relationship between EACO, HbCO (NCT01547793, cohort A) and other biomarkers of hemolysis in adults with SCD at steady state as part of the clinical cohort at the National Institutes of Health Clinical Center, Bethesda, Maryland, USA (NCT00011648, cohort B). Of the patients included in the cohort B, all routine samples with results on HbCO were included in the analyses. In a subgroup of the cohort B with data available on HbCO, echocardiography and/or mortality, we evaluated the correlation between LDH/HbCO ratio and echocardiographic markers of PH and all-cause mortality (cohort C). Combining all recognized available markers for hemolysis (total bilirubin, AST, absolute reticulocyte count, hemoglobin, median LDH, median HbCO and LDH/HbCO ratio) in a multivariate Cox proportional hazards model for survival led to selection of a predictive model encompassing three biomarkers: LD/HbCO ratio, AST and hemoglobin. Of these three markers, the LD/HbCO ratio was the most predictive factor. We also conducted univariate correlations with clinical outcome indicators. Main findings Erythropoietic and hemolytic laboratory parameters of the cohorts are provided in Table 1. HbCO concentrations and EACO were strongly correlated (Pearson's correlation r=0.66, p

Description: Background: Sickle cell disease (SCD) is a chronic illness associated with varying degrees of decrease in exercise capacity. Affected children are as much as 50% less physically active than controls. The reasons for the reluctance of SCD children to participate in sports and/or intense physical activities are complex, not entirely understood and not well studied in this young population with chronic anemia. The six minute walk test (6MWT) is an exercise test, validated as screening tool for assessing cardiopulmonary functional status in several pediatric cohorts of healthy children and in children with chronic illnesses including SCD. This test is a submaximal exercise test and reflects the patient’s capacity to undertake daily activities. We have previously reported that children with SCD experience a decrease in oxy-hemoglobin oxygen saturation as determined by pulse oximetry after the test. Material and methods: We performed a prospective, multicenter study of cardiopulmonary function in 409 children with SCD (age 5-20 years) and 70 age and race matched controls as part of the PUSH study. Each subject was at steady state, at least three weeks from an acute exacerbation and/or a blood transfusion. Subjects and controls underwent echocardiogram, hematologic testing, and 6MWT according to standard protocols. 6MW distance was compared between SCD cases and controls by the student t-test. A linear regression model was developed to assess the independent predictors of 6MW in patients. Results: SCD patients had lower 6MW distance (p

Description: Background: Approximately 57% of individuals with Sickle Cell Disease (SCD) suffer from sleep disorders and poor sleep quality. Poor sleep quality may cause excessive daytime sleepiness and is often associated with psychosocial and clinical factors contributing to disease burden and stress levels. One of these psychosocial factors is John Henryism (JH). Defined as a high-effort, active coping style, JH is used by persons with a strong determination to succeed in the face of chronic stressors. Both sleep and JH have mostly been shown to be negatively associated with cardiovascular health. Living with SCD is a unique stressor and how persons cope with their disease may impact their quality of life and health outcomes. The objective of this study is to 1) evaluate the impact of sleep quality and 2) quantify the effect of sleep quality on high-effort coping among persons with SCD. Methods: The sample comprised 191 adults aged 19-71 with SCD. Most participants were women (57%) and had a mean age of 39 years (SD+12.2) (see Table 1). All participants were enrolled in the Insights into Microbiome and Environmental Contributions to SCD and Leg Ulcers (INSIGHTS) study (NCT02156102). All participants were administered a variety of psychosocial measures, a comprehensive medical history and physical exam, and provided blood and saliva samples for clinical and research analysis. Our binary outcome assessed participants' high or low utilization of JH coping style by using the John Henryism Active Coping Scale (JHAC12). JHAC12 scores were measured from participant responses to a 12-item Likert scale. Scores range from 12 to 60 with higher scores indicting higher utilization of JH active coping. Based on the median JH score of our participants, scores between 12-50.9 were categorized as low utilization of JH and scores between 51-60 were categorized as high utilization of JH. Predictors included demographic data and psychosocial measures. Sleep quality was assessed via clinical and survey measures. Clinically, obstructive sleep apnea was self-reported during a comprehensive medical exam. The ASCQ-ME sleep survey is a 5-item measure, and was used to ascertain participant sleep patterns within the past seven days. Scores range from 40 to 60. Scores less than 50 are considered abnormal. Multivariable logistic regression was performed to evaluate differences within the cohort. Results: Mean ASCQ-ME sleep score of the entire cohort was 46, indicating worse sleep quality for participants compared to the ASCQ-ME national SCD reference cohort. Obstructive sleep-apnea was self-reported by 23 participants (12%). The mean JH score was 52, indicating high utilization of active coping. Poorer sleep quality was associated with higher JH coping (OR:1.14, 95% CI: [1.06-1.22]) (see Table 2). There were no significant associations between utilization of JH active coping with the demographic data including sex, age, education and marital status. Worse sleep quality within the SCD cohort was associated with increased usage of hydroxyurea (r= .16, p

Description: Background: Sickle cell disease (SCD) is a complex genetic disorder affecting mainly people of African origin. A hallmark of SCD is vaso-occlusive crisis (VOC) - this event is acutely painful and the primary cause of hospitalization in SCD patients. VOC can lead to life-threatening complications such as acute chest syndrome. SCD is also associated with chronic complications including pulmonary hypertension, damage to organs and shortened life expectancy. Therefore, effective management and treatment strategies are essential to reduce burden of illness and ensure high quality of life for the patient. Aim: To survey the treatment and management strategies used by patients with SCD, and to determine patient satisfaction levels. Methods: SWAY is an ongoing multi-country, cross-sectional survey of SCD patients, caregivers and treating physicians. The survey, conducted online and in print, includes 6 categories: demographics, symptoms, impact of disease and use of a caregiver, impact on work and finances, disease management/treatment approaches, and patient-physician relationship. Where relevant, questions include a 7-point severity scale for each statement; a score of 5−7 indicates 'high severity/impact'. Patient enrollment is via treating physicians and patient association groups. The enrollment target is approximately 2000 patients. Results: To date, 1513 SCD patients (48% male, mean age 24.1 years, 63% HbSS and 30% HbSC disease) have been surveyed from 11 countries across North and South America, Europe and Africa. When considering the main person responsible for SCD treatment and management, patients primarily reported management by an SCD specialist (59% of patients) or GP/family doctor (20%). Most patients were satisfied with the frequency of interaction with their doctor (78%) and reported they are confident they are being assessed and treated properly (66%; based on high-impact scores 5−7). Accordingly, 60% of patients (scoring 5−7) reported sharing the same goals for SCD management and treatment as their doctor. The most common treatment goals for patients are to improve quality of life (80% of patients), prevent SCD worsening (59%), improve long-term survival (42%) and improve overall symptoms (40%). Patients reported receiving ongoing treatment with folic acid (58%), antibiotics (37%), anti-inflammatories (37%), over-the-counter pain medication (37%), opioids (35%), hydroxyurea (23%), blood transfusions (10%) and L-glutamine (4%). Having surgery or a medical procedure to manage their SCD was reported by 47% of patients, with gall bladder removal (16%), port placement (15%) and splenectomy (11%) being the most frequent. Although 63% of patients (scoring 5−7) indicated satisfaction with their treatment received to manage their SCD, 75% of patients (scoring 5−7) agreed they would like an alternative treatment to their current pain management medication, and 67% of patients would like additional professional emotional support. In the 12 months before survey completion, 7829 VOCs were reported (mean of 5.2 VOCs per patient); 8% of patients experienced 0 VOCs, 51% experienced 1−4 VOCs and 40% experienced ≥5 VOCs. Of these, 38% of VOCs led to overnight hospitalization, 24% were managed at home and 19% were treated in the emergency room. The main reasons that patients chose to manage their VOCs at home include a previous poor experience at hospital (40%), the opinion that medical assistance was not required (28%), the perception that medical professionals do not understand SCD (27%) and the cost of hospital treatment (22%; 41% of patients have no health insurance). Patients who self-managed their VOCs primarily did so with rest/sleep (73%), by drinking fluids (72%) and with opioid-based analgesia (58%). Conclusions: This interim analysis of the SWAY survey suggests that although many patients report satisfaction with their current level of management and treatment, there is still a need for additional healthcare support and alternative treatments. Underlining this, many patients experiencing VOCs do not seek medical assistance despite the potential for life-threatening complications, and 〉75% of patients surveyed are not receiving hydroxyurea even though the majority are cared for by SCD specialists. Further data collection and analysis will highlight any geographic differences in SCD management strategies and help identify any region-specific unmet patient needs. Disclosures James: Novartis: Honoraria; Sickle Cell Society: Employment. Andemariam:NovoNordisk: Membership on an entity's Board of Directors or advisory committees; New Health Sciences: Membership on an entity's Board of Directors or advisory committees; Emmaus: Membership on an entity's Board of Directors or advisory committees; Cyclerion: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Imara: Research Funding; Global Blood Therapeutics: Other: DSMB Member; Community Health Network of Connecticut: Consultancy; Bluebird Bio: Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Membership on an entity's Board of Directors or advisory committees; Terumo BCT: Membership on an entity's Board of Directors or advisory committees. El-Rassi:Novartis Pharmaceuticals: Research Funding. Francis-Gibson:Sickle Cell Disease Association of America: Employment. Nero:Novartis: Consultancy. Minniti:Doris Duke Foundation: Research Funding. Trimnell:Novartis: Consultancy; Global Blood Therapeutics: Consultancy; Cyclerion: Consultancy. Abboud:Novo Nordisk: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Modus: Research Funding; CRSPR Therapeutics: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Research Funding; Amgen: Other: Travel support; Eli Lilly: Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding; GBT: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Colombatti:Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Addmedica: Membership on an entity's Board of Directors or advisory committees; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees. de Montalembert:AddMedica: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; bluebird bio, Inc: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Jastaniah:Novartis: Consultancy, Honoraria. Nur:Novartis: Consultancy. DeBonnett:Novartis Pharmaceuticals Corporation: Employment. Osunkwo:Micella Biopharma: Other: DSMB Member ; Terumo: Speakers Bureau; Pfizer: Consultancy; Novartis: Consultancy, Speakers Bureau.

Description: Abstract 1511 Poster Board I-534 Background What determines the degree of hemolysis and of anemia in patients with hemoglobin SS is not fully known. The rate of hemolysis and severity of anemia are ameliorated by the presence of alpha thalassemia and by higher hemoglobin F percentage. Mild G6PD deficiency in the form of G6PD-202/-376 may be associated with episodic hemolysis in individuals of African descent, but past studies indicated little influence of G6PD-202/-376 on the degree of hemolysis and anemia in sickle cell disease patients (1,2). In this study we examined the roles of single and double α-globin deletions and G6PD-202/-376 on the degree of hemolysis and the hemoglobin concentration in hemoglobin SS patients. Methods Two hundred sixty two children and adolescents with hemoglobin SS were recruited at three tertiary medical centers and studied at steady state. Principal component analysis was used to develop a hemolytic component from concentrations of lactate dehydrogenase, aspartate aminotransferase and bilirubin. PCR was used to determine the presence of α-thalassemia and G6PD-202/-376. Multivariate models were employed to determine the independent effects of these genotypes on hemoglobin concentration and degree of hemolysis. Results Single a-globin deletion was associated with an estimated 0.4 g/dL increase in steady-state hemoglobin concentration and double α-globin gene deletion with a 0.8 g/dL increase (P = 0.005 for trend) due to, progressively lower degrees of hemolysis (P = 0.004). G6PD-202/-376 was associated with an estimated 0.7 g/dL decrease in the hemoglobin concentration (P = 0.003) (Figure 1a), but this observation could not be explained by increased hemolysis. Rather, the reticulocyte count was an estimated 22% lower with G6PD-202/-376 (P = 0.032) (Figure 1b). Discussion G6PD -202/-376 may be associated with lower hemoglobin concentration in sickle cell anemia and the mechanism is probably impaired erythropoiesis rather than hemolysis. A recent study (3) indicates that G6PD is needed for definitive erythropoiesis as well as for normal survival of red blood cells in the periphery. Our present findings raise the possibility that, in the setting of the markedly increased erythropoiesis of sickle cell anemia, G6PD-202/-376 may result in impairment in erythropoiesis that is discernible in the peripheral blood hemoglobin concentration. Disclosures No relevant conflicts of interest to declare.

Description: Abstract 2664 Background: The six-minute walk (6MW) test is used in pediatrics in clinical practice and research to determine cardiopulmonary functional status. A change in 6MW may be affected by factors not strictly related to cardiopulmonary function, which may be different in different patient populations. In children and adolescents, age and height has been found to be a strong predictor of 6MW distance. We set out to study the effects of hematological and echocardiographic variables on 6MW distance in children with sickle cell disease (SCD) and its changes over time. Methods: We reviewed prospectively collected hematological, 6MW distance, and echocardiographic data from four hundred children with SCD (including 311 Hb SS or β0) and 69 controls (including 21 Hb AS) enrolled in PUSH (Pulmonary Hypertension and the Hypoxic Response in SCD). Subjects were evaluated at baseline and after 18–24 months, as per protocol. An un-encouraged 6MW was performed in children 5 years or older by trained personnel as per the guidelines of the American Thoracic Society. Subjects were studied at steady state, at least three weeks after any acute exacerbation of SCD. We used ANOVA for univariate analysis and stepwise linear regression for multivariate analysis. Results: Median (interquartile range) 6MW in severe SCD genotype (SS and S-β0) was 444 (399-508) and in controls was 495 meters (435-539) (P = 0.0002), while it was 461 meters (408-518) in milder SCD genotypes (P=0.2 for comparison with severe genotypes) (Table 1). In multivariate analysis, Hb, WBC and history of frequent pain episodes were significantly associated to distance of 6MW. Follow up 6MW obtained in 174 SCD subjects revealed a decline of 10% or more in distance in 22% of subjects with severe genotypes and 33% of other genotypes. The decline was more frequent in the subset of SS subjects with TRV〉2.59 (40% vs 19%). CONCLUSION: Six minute walk distance is significantly shorter in children with SCD, even as young as 5 years of age, when compared to age and race appropriate controls, indicating early compromise of exercise capacity. SS and S-β-0 genotype subjects have more impairment of exercise capacity compared to milder genotypes. Predictors of 6MW distance are similar in SCD and non SCD subjects, which validates the use of this test in this patient population. Longitudinal changes in subjects with SCD are similar, with declines in about a quarter of the subjects. Patients with SS who have an elevated TRV have the highest rate of decline in 6MW. These results validate the use of 6MW as a tool for assessing exercise capacity in children with SCD. Disclosures: No relevant conflicts of interest to declare.

Description: Hydroxyurea and higher hemoglobin F improve the clinical course and survival in sickle cell disease, but their roles in protecting from pulmonary hypertension are not clear. We studied 399 children and adolescents with sickle cell disease at steady state; 38% were being treated with hydroxyurea. Patients on hydroxyurea had higher hemoglobin concentration and lower values for a hemolytic component derived from 4 markers of hemolysis (P ≤ .002) but no difference in tricuspid regurgitation velocity compared with those not receiving hydroxyurea; they also had higher hemoglobin F (P 〈 .001) and erythropoietin (P = .012) levels. Hemoglobin F correlated positively with erythropoietin even after adjustment for hemoglobin concentration (P 〈 .001). Greater hemoglobin F and erythropoietin each independently predicted higher regurgitation velocity in addition to the hemolytic component (P ≤ .023). In conclusion, increase in hemoglobin F in sickle cell disease may be associated with relatively lower tissue oxygen delivery as reflected in higher erythropoietin concentration. Greater levels of erythropoietin or hemoglobin F were independently associated with higher tricuspid regurgitation velocity after adjustment for degree of hemolysis, suggesting an independent relationship of hypoxia with higher systolic pulmonary artery pressure. The hemolysis-lowering and hemoglobin F–augmenting effects of hydroxyurea may exert countervailing influences on pulmonary blood pressure in sickle cell disease.