Profound Alteration of Host Response in Severe Malarial Anemia By Sickle Cell Disease: Reduction of Parasite Sequestration and Inflammation, Upregulation of Angiopoietin-2

Introduction. Plasmodium falciparum malaria is a major cause of morbidity in African children with sickle cell anemia (SCA). Factors associated with severe disease and mortality in malaria, including tumor necrosis factor (TNF)-alpha and components of the angiopoietin (Angpt)-Tie-2 system, have also been implicated in the pathogenesis and clinical severity of SCA. However, there is no data on how these factors are altered in children with SCA during severe malaria. Methods. A total of 232 children who presented with severe malarial anemia (hemoglobin < 5 g/dL with Plasmodium parasitemia on peripheral blood smear) were enrolled in a prospective study of severe malaria at Mulago National Referral Hospital in Kampala, Uganda. No child had known SCA at the time of severe malarial anemia diagnosis. Samples from enrolled children were subsequently tested by genotyping for the presence of hemoglobin S (HbS) using a TaqMan assay at rs334. Clinical and laboratory parameters, plasma markers of inflammation and endothelial activation, and the estimated total, sequestered, and circulating parasite biomass were compared in children with HbSS compared to HbAA. Results. The study cohort included 208 children with HbAA (90.4%), 22 children with HbSS (9.6%), and 2 with HbAS. Children with HbSS were older than children with HbAA (Table 1), so all comparisons were adjusted for age. Children with HbSS versus HbAA did not differ significantly in duration of symptoms, clinical signs, disease severity, or degree of peripheral P. falciparum parasitemia. However, children with HbSS had significantly lower concentrations of PfHRP2, a marker of total parasite biomass, and lower levels of estimated sequestered parasite biomass (Table 1). Children with HbSS had pronounced leukocytosis, a feature of chronic inflammation in SCA, but had significantly lower concentrations of the inflammatory biomarkers C-reactive protein and alpha-1-acid glycoprotein and the pro-inflammatory cytokine TNF-alpha than children with HbAA (Table 1). In contrast, concentrations of angiopoietin-2 (Angpt-2), a marker of endothelial dysregulation that has been associated with mortality in severe malaria, were 3-fold greater in children with HbSS than HbAA (Table 1), and were associated with an increased risk of post-discharge recurrent malaria in the cohort, after adjustment for age, sex, and hemoglobin S genotype (odds ratio per log-10 increase in Angpt-2 [95% confidence interval], 2.11 [1.01, 4.38]). Conclusion. In this population, undiagnosed SCA is common in children with severe malarial anemia. During episodes of severe malarial anemia, children with SCA suppress parasite sequestration and inflammation but upregulate Angpt-2, which may increase risk of recurrence of malaria. Disclosures Conroy: ALC: Patents & Royalties: angiopoietin-1, angiopoietin-2. Ware:Addmedica: Other: Research Drug Donation; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Nova Laboratories: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Membership on an entity's Board of Directors or advisory committees; Novartis: Other: DSMB; Bristol Myers Squibb: Other: Research Drug Donation.

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Trial in Progress: The Randomized, Double-Blind, Placebo-Controlled Phase IIa CROSSWALK-c Trial Evaluating the Efficacy of Crovalimab As Adjunct Treatment in the Prevention of Vaso-Occlusive Episodes (VOEs) in Patients with Sickle Cell Disease (SCD)

Blood ◽

10.1182/blood-2021-151222 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3111-3111

Author(s):

Michael Callaghan ◽

Kenneth I. Ataga ◽

Lucia De Franceschi ◽

Caterina Minniti ◽

Nadiesh Balachandran ◽

...

Keyword(s):

Board Of Directors ◽

Point Mutation ◽

Sickle Cell ◽

Research Funding ◽

Globin Gene ◽

Organ Damage ◽

Efficacy And Safety ◽

Advisory Committees ◽

Double Blind ◽

Hemoglobin S

Abstract Background SCD is a group of autosomal recessive red blood cell (RBC) disorders caused by a single point mutation in the β- globin gene, with either homozygous inheritance, or heterozygous co-inheritance with other pathogenic variants of the β-globin gene. This point mutation results in the production of hemoglobin S, which polymerizes within RBCs under certain conditions, leading to the distortion of the RBC membrane and generation of dense and sickle RBCs. These pathologic RBCs contribute to microvascular occlusions in patients with SCD, which present as acute painful episodes called VOEs. In addition to VOEs, patients with SCD may experience severe chronic anemia, chronic pain, immune dysfunction, and progressive multi-organ damage. The current treatment strategy for patients with SCD includes hydroxyurea, along with newer treatments such as L-glutamine, crizanlizumab, and voxelotor. However, despite the availability of these treatments, considerable morbidity and mortality among patients with SCD represents a significant unmet medical need. Activation of the complement pathway has been described in patients with SCD at baseline, in acute pain crisis, and in delayed hemolytic transfusion reaction. Accumulating nonclinical data suggest the potential multimodal role for complement dysregulation in the pathophysiology of SCD, including vaso-occlusion, hemolysis, inflammation, thrombogenicity, endothelial activation, and end-organ damage (Roumenina et al. Am J Hematol 2020). Crovalimab is a novel anti-C5 monoclonal antibody that allows for small-volume subcutaneous (SC) self-injection. Crovalimab demonstrated rapid and sustained complement inhibition with promising efficacy and safety in a Phase I/II study (Röth et al. Blood 2020), in patients with paroxysmal nocturnal hemoglobinuria, a complement-mediated disorder. Study Design and Methods CROSSWALK-c (NCT number pending) is a placebo-controlled, randomized, double-blind, Phase IIa study evaluating the efficacy and safety of crovalimab as adjunct therapy in preventing VOEs in patients with SCD. Patients aged ≥ 12 years to ≤ 55 years, weighing ≥ 40 kg, with a confirmed diagnosis of SCD, homozygous hemoglobin S (HbSS) or sickle cell β 0 thalassemia (HbSβ 0), and presenting with ≥ 2 to ≤ 10 VOEs are eligible for this study. Patients on concurrent SCD-directed therapies are also eligible. Vaccination against Neisseria meningitidis, Haemophilus influenzae type B, and Streptococcus pneumonia are required for enrollment. Patients with a history of hematopoietic stem cell transplant are excluded from the study. Eligible patients will be randomized 1:1 to the crovalimab or placebo treatment arms (Figure). An initial intravenous loading dose of crovalimab or placebo will be administered on Day 1 Week 1, followed by four weekly SC doses on Day 2 Week 1, and then on Weeks 2-4. Maintenance dosing will be administered from Week 5, followed by once every 4 weeks thereafter, for 48 weeks. All patients will receive study treatment according to a weight-based tiered dosing schedule. The primary objective is to evaluate the efficacy of crovalimab compared with placebo, based on the annualized rate of medical facility VOEs. Secondary efficacy objectives include the annualized rate of acute chest syndrome, the annualized rate of home VOE, and change in urinary albumin-creatinine ratio, tricuspid regurgitant jet velocity, and Patient-Reported Outcomes Measurement Information System (PROMIS)-Fatigue score in adults, from baseline to Week 49. Safety, pharmacokinetics, immunogenicity, and exploratory biomarker objectives will also be evaluated. Figure 1 Figure 1. Disclosures Callaghan: Agios Pharmaceuticals: Current Employment; Roche/Genentech: Consultancy, Speakers Bureau; Global Blood Therapeutics: Consultancy, Speakers Bureau; Forma: Consultancy; Hema Biologics: Consultancy; Takeda: Consultancy, Speakers Bureau; Sanofi: Consultancy; BioMarin: Consultancy; Spark: Consultancy; uniQure: Consultancy; Chiesi: Consultancy; Kedrion: Consultancy; Pfizer: Consultancy. Ataga: Novartis: Membership on an entity's Board of Directors or advisory committees; Agios Pharmaceuticals: Consultancy; Forma Therapeutics: 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; F. Hoffmann-La Roche Ltd: Consultancy; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees. De Franceschi: F. Hoffmann-La Roche Ltd: Consultancy. Minniti: CSL Behring: Other: Endpoint adjudicator ; Forma: Consultancy; Novo Nordisk: Consultancy; Chiesi: Consultancy; Bluebird Bio: Other: Endpoint adjudicator ; Novartis: Consultancy; GBT: Consultancy; F. Hoffmann-La Roche Ltd: Consultancy. Balachandran: F. Hoffmann-La Roche Ltd: Current Employment. Imbs: F. Hoffmann-La Roche Ltd: Consultancy; Certara Inc.: Current Employment. Perretti: F. Hoffmann-La Roche Ltd: Current Employment. Ramos: Genentech, Inc.: Current Employment. Sostelly: F. Hoffmann-La Roche Ltd: Current Employment. Bartolucci: Bluebird: Consultancy, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Lecture fees, Steering committee, Research Funding; Fabre Foundation: Research Funding; Jazz Pharma: Other: Lecture fees; AGIOS: Consultancy; INNOVHEM: Other: Co-founder; Emmaus: Consultancy; Addmedica: Consultancy, Other: Lecture fees, Research Funding; Hemanext: Consultancy; F. Hoffmann-La Roche Ltd: Consultancy; GBT: Consultancy.

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Hydroxyurea Pharmacokinetic Profiles in Children Treated for Extreme Thrombocytosis after Total Pancreatectomy with Islet Cell Autotransplant Demonstrate Poor Absorption

Blood ◽

10.1182/blood-2019-127378 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4893-4893

Author(s):

Alexander A Boucher ◽

Min Dong ◽

Anu Marahatta ◽

Adriane Hausfeld ◽

Thad A. Howard ◽

...

Keyword(s):

Board Of Directors ◽

Sickle Cell ◽

Islet Cell ◽

Drug Exposure ◽

Total Pancreatectomy ◽

Cell Transplant ◽

Pancreatic Islet Cell ◽

Advisory Committees ◽

Time Curve ◽

Research Drug

Background Total pancreatectomy with islet autotransplantation (TPIAT) is a surgical treatment for chronic recurrent pancreatitis that involves splenectomy, pancreatectomy and creation of a Roux-en-Y, followed by re-injection of the pancreatic islets into the portal vein. Postoperatively, patients develop a sustained and extreme thrombocytosis (ExT) with platelets ≥1000 K/μL, a response more exaggerated than the typical post-splenectomy course (Gurria JP et al, Pancreas 2019). Empiric aspirin (antiplatelet effect) and hydroxyurea (cytoreduction) are initiated postoperatively per a standard protocol. The pharmacokinetic (PK) and pharmacodynamic (PD) profiles of hydroxyurea have not been studied in children other than young children with sickle cell disease; neither dose nor dose interval have been evaluated in TPIAT patients. Recently a population PK model was developed to support individualized hydroxyurea dosing in patients with sickle cell anemia (SCA; Dong M et al, Br J Clin Pharmacol 2016). In a prospective evaluation as part of the Therapeutic Response Evaluation and Adherence Trial (TREAT, McGann PT et al, Am J Hematol 2019), PK-guided individualized dosing resulted in better clinical and laboratory benefits than with conventional weight-based dosing. This study aimed to determine if a hydroxyurea PK model could be developed for non-SCA children dosed postoperatively for control of TPIAT-associated ExT, and if so, to compare it to previously published models for SCA. Methods A prospective single-site pilot study was performed in patients ages 0-21 years who underwent TPIAT between April 2018 and June 2019. Whole blood was collected via finger stick or venipuncture at 3 time points (20 minutes, 1 hour, 4 hours) after the initial hydroxyurea dose (15-20 mg/kg), given between postoperative day 5-7 (PK1). Plasma hydroxyurea was quantified by high performance liquid chromatography on 150-200 μL plasma. Testing was repeated once 2-6 months postoperatively (PK2) to determine whether PK profiles changed over time in relation to surgery. PK analyses and estimation of the area under the concentration-time curve (AUC) as a measure of exposure were performed using MW/Pharm (Mediware, Prague, Czech Republic). PK data from HUSTLE (NCT00305175) were used for comparison to SCA patients. Results Of 19 enrolled subjects, 15 had evaluable results: 7 had both PK collections while 8 had a single collection (5 only had PK1, 3 only had PK2). All 5 patients with only PK1 measurements had discontinued hydroxyurea by the time PK2 samples would have been collected, whereas those with only PK2 all had unsuccessful PK1 collection attempts. Mean age was 13.5 years [standard deviation (SD) 5] with mean weight-based dose 14 mg/kg (SD 3.4). Serum creatinine was normal for age in all patients. Hydroxyurea suspension was delivered via jejunal tube at PK1 while oral tablets were used at PK2 per surgical protocol. The AUC was 60.1 h*μg/ml at PK1 and 68.6 h*μg/ml at PK2. When compared to HUSTLE cohort (Figure 1), TPIAT subjects overall had lower drug exposure (AUC), worse for PK1 than PK2, especially when hydroxyurea concentration was normalized to dose. TPIAT patients also appear to have had slower absorption, evidenced by still-rising hydroxyurea concentrations after 1 hour, compared to 20-30 minute peak concentrations in HUSTLE. Conclusions TPIAT subjects treated empirically with hydroxyurea to modulate ExT have decreased absorption and overall lower concentrations and drug exposure relative to our SCA population. Lower bioavailability and/or altered absorption may in part be caused by differences in formulation (suspension versus tablet) and route of administration (oral versus jejunal) along with postoperative anatomic changes not present in the SCA cohort, since Roux-en-Y may alter drug absorption and metabolism (Rogers CC et al, Clin Transpl2008). It is unknown whether higher enteral hydroxyurea doses would increase exposure and effect. Additional evaluation of the absorption characteristics and PK/PD of hydroxyurea in TPIAT patients, as well as efficacy, are urgently needed. Figure 1 Disclosures Ware: Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Nova Laboratories: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Membership on an entity's Board of Directors or advisory committees; Novartis: Other: DSMB; Bristol Myers Squibb: Other: Research Drug Donation; Addmedica: Other: Research Drug Donation. OffLabel Disclosure: Hydroxyurea to reduce extreme thrombocytosis after splenectomy/pancreatic islet cell transplant in children

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Hydroxyurea Therapy to Prevent Incident Stroke Among Children with Sickle Cell Anaemia in Jamaica: The Extend Trial

Blood ◽

10.1182/blood-2019-126781 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 2269-2269

Author(s):

Angela Rankine-Mullings ◽

Marvin Ellsworth Reid ◽

Deanne Soares ◽

Carolyn Taylor-Bryan ◽

Margaret Wisdom-Phipps ◽

...

Keyword(s):

Board Of Directors ◽

Sickle Cell ◽

Sickle Cell Anemia ◽

Risk Group ◽

Advisory Board ◽

Stroke Recurrence ◽

Open Label ◽

Advisory Committees ◽

Previous Stroke ◽

Research Drug

Incident stroke, both primary and recurrent are common in children with sickle cell anemia (SCA) in Jamaica with incidences of 7.8% by 14 years of age and 29/100 person-years respectively. Cerebral vasculopathy manifested by elevated transcranial doppler (TCD) velocity (>170 cm/sec) is the major risk factor for both with a prevalence of 19.8% among Jamaican children with SCA. Chronic blood transfusion is the standard of care to reduce stroke risk and recurrence in children with SCA in high income countries, but in low-resource settings where blood availability, safety and local acceptance are limited, hydroxyurea (HU) is emerging as a viable alternative. However, the efficacy of HU for incident stroke prevention in children with newly diagnosed severe cerebrovascular disease without the use of transfusions in a low resource setting like Jamaica is unclear. The EXpanding Treatment for Existing Neurological Disease (EXTEND) trial (ClinicalTrials.gov NCT02556099) was designed to investigate the effects of open label HU on TCD velocities after 18 months of treatment, compared to the pre-treatment value. Secondary aims included the effects of HU on the incidence of neurological events including magnetic resonance imaging (MRI), magnetic resonance angiography (MRA) changes, non-neurological events, hematological responses and toxicity. We enrolled 43 children with SCA, 2 to 17 years of age , between Nov 2014 and April 2016, stratified into 3 groups: Low Risk Group (LRG) - On Hydroxyurea with TCD ≥170 cm/sec, N=12; Medium Risk Group (MRG) - HU naive with TCD ≥170 cm/sec, N=21; and High Risk Group (HRG) - Previous Stroke, N=10. All children received HU initially at 20 mg/kg/day followed by two monthly dose escalation using weight and pre-defined laboratory criteria to maximum tolerated dose (MTD) and thereafter 3 monthly visits. The average HU dose at MTD (mean±1SD) was 25.3±0.4 mg/kg. TCD was performed every 6 months according to the Stroke Prevention in Sickle Cell Anemia (STOP) protocol. The average age at enrollment was 7.7±2.6 years, with MRG significantly younger than HRG (6.7±2.0 years vs 9.2±3.7 years; p<0.012). At baseline, there were no significant differences in gender or previous history of vaso-occlusive painful events, dactylitis, Acute Chest Syndrome, Acute Splenic Sequestration, transfusion history, or frequency of hospitalization among the groups. As expected, the LRG cohort on HU had a higher baseline hemoglobin concentration (Hb=9.1±1.3 g/dl) than MRG (7.8±0.8 g/dl) and HRG (7.4±0.9 g/dl), p<0.003) but there were no significant differences in % fetal hemoglobin (%HbF, cohort average = 13.5±6.8%) or white blood cell count (WBC, cohort average = 11.9±3.7 x 109/L). Mean TCD velocity was lowest in LRG and highest in HRG (Fig 1). The primary study endpoint was change in TCD velocity after 18 months of HU treatment, and across all groups TCD velocities decreased by an average of 24±30 cm/sec, with no differences by group (Fig 1). The entire cohort was observed for 697.2 person-months on protocol HU therapy with an incidence rate for new infarcts (IR) of 12/100 person-years. HRG had significantly higher (p<0.004) IR with 6 events in 5 participants (IR=43/100 person-years) compared with 1 new infarct in the LRG (IR=6/100 person-years) and, none in MRG (IR=0). All children with new infarcts during the study had abnormal baseline MRI and MRA, and some had previous stroke recurrence. Laboratory benefits of HU included clinically significant increases in Hb (2.0±0.9 g/dl) and (1.7±0.7 g/dl) in MRG and HRG as well as increases in %HbF, (17.8±10.7 ) in MRG and (14.4±14) in HRG plus significant decreases in WBC (6.5±3.7 x 109/L) and (4.5±3.3 x 109/L) in MRG and HRG respectively. There were no significant changes in hematology for LRG. Overall, HU was well-tolerated with 0.53 recorded toxicities/year during 697.2 patient-months of treatment. Treatment with HU at MTD for 18 months in children at high risk for strokes was effective in lowering TCD velocities with laboratory benefits and was safe. However, while the overall incidence of new neurological events was low in children with elevated TCD velocities, children with previous stroke experienced higher rates of stroke recurrence on HU therapy. Thus, the incidence of neurological events in children with previous stroke may be related to severe vasculopathy that is challenging to manage using HU, transfusions, or newer disease-modifying therapies. Disclosures Rankine-Mullings: Nova Laboratories Limited, Martin House, Gloucester Crescent, Wigston, Leicester, LE18 4YL: Other: I am Principal investigator for the performance site at the University of the West Indies for the protocol A prospective open label, pharmacokinetic study of an oral Hydroxyurea solution in children with sickle cell anemia . Knight-Madden:Global Blood Therapeutics: Research Funding; Global Blood Therapeutics: Other: Sponsor of a conference held by Sickle Cell Unit in 2017; Addmedica: Other: Sponsor of a conference held by Sickle Cell Unit in 2017; BlueBird Bio: Other: Sponsor of a conference held by Sickle Cell Unit in 2017; Nova Laboratories: Other: Sponsor of a conference held by Sickle Cell Unit in 2017; Abbot International: Other: Sponsor of a conference held by Sickle Cell Unit in 2017; Pfizer: Other: Advisory Board on SCD 2017; Abbott Nutrition: Other: Sponsor of a conference held by Sickle Cell Unit in 2017; Nova Laboratories: Advisory Board on SCD 2017, Research Funding. Adams:Bluebird: Consultancy; GBT: Consultancy, Other: consultancy to companies GBT and Blueburd Bio. Ware:CSL Behring: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Other: Research Drug Donation; Addmedica: Other: Research Drug Donation; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees; Novartis: Other: DSMB; Nova Laboratories: Membership on an entity's Board of Directors or advisory committees.

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Altered Immune Response in Severe Malaria Anemia in Children.

Blood ◽

10.1182/blood.v108.11.1303.1303 ◽

2006 ◽

Vol 108 (11) ◽

pp. 1303-1303 ◽

Cited By ~ 1

Author(s):

Victor R. Gordeuk ◽

Ishmael Kasvosve ◽

Janneke van Dijk ◽

Guenter Weiss ◽

Zufan Debebe ◽

...

Keyword(s):

Severe Malaria ◽

Interferon Gamma ◽

Plasma Levels ◽

Uncomplicated Malaria ◽

Interleukin 10 ◽

Tnf Alpha ◽

Severe Anemia ◽

Severe Malarial Anemia ◽

Younger Age ◽

Malarial Anemia

Abstract We prospectively assessed immune markers in children <6 years with severe malarial anemia (hemoglobin <5.0 g/dL; n = 72) and uncomplicated malaria (n = 69) who presented to Macha Mission Hospital in Zambia’s Southern Province. We also studied 70 children <6 years who presented to well child clinics in Harare, Zimbabwe as controls. Compared to controls, children with uncomplicated malaria had significantly higher temperatures and parasite counts, lower hemoglobin and platelet concentrations, higher plasma levels of interferon-gamma, tumor necrosis factor alpha, and interleukin 10 and lower levels of monocyte inhibitory factor (MIF). Compared to uncomplicated malaria, severe malaria anemia was associated with younger age, longer duration of fever and lower temperature on admission. Reticulocyte index and serum concentrations of bilirubin and LDH did not differ between the malaria groups, suggesting that unusually severe extra- or intra-medullary hemolysis did not explain the severe anemia. Higher white blood cell and platelet counts in the severe malaria group suggested that pan-suppression of the marrow was also not the primary cause. Of originally selected measures of inflammation, plasma levels of TNF-alpha and MIF did not differ between the malaria groups, but concentrations of both interferon-gamma and interleukin-10 were significantly lower in the severe anemia group (P <0.006). Additional testing revealed levels of interleukin-1alpha, interleukin-6, and IP-10 to be lower and levels of sFAS to be higher in the children with severe anemia versus uncomplicated malaria (P <0.0005). In a logistic regression model, severe malarial anemia was associated with younger age (P = 0.010), prior treatment with sulfadoxine/pyrimethamine or traditional medicine (P <0.32), lower levels of Interleukin-10 (P = 0.025) and higher levels of sFAS (P = 0.003) and TNFa (P = 0.013). Our results are consistent with a multifactorial cause of severe malarial anemia, possibly including infection with resistant plasmodia, over-expression of TNF-alpha in conjunction with under-expression of IL-10, and increased apoptosis.

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Lack of mortality in 22 children with sickle cell anemia and severe malarial anemia

Pediatric Blood & Cancer ◽

10.1002/pbc.26745 ◽

2017 ◽

Vol 65 (1) ◽

pp. e26745 ◽

Cited By ~ 3

Author(s):

Robert O. Opoka ◽

Paul Bangirana ◽

Richard Idro ◽

Estela Shabani ◽

Ruth Namazzi ◽

...

Keyword(s):

Sickle Cell ◽

Sickle Cell Anemia ◽

Severe Malarial Anemia ◽

Malarial Anemia

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Splenomegaly in Children with Sickle Cell Anemia Receiving Hydroxyurea in Sub-Saharan Africa

Blood ◽

10.1182/blood-2019-129937 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 993-993

Author(s):

Leon Tshilolo ◽

George A. Tomlinson ◽

Patrick T. McGann ◽

Teresa S. Latham ◽

Peter Olupot-Olupot ◽

...

Keyword(s):

Board Of Directors ◽

Sickle Cell ◽

Sickle Cell Anemia ◽

Growth Parameters ◽

Sub Saharan Africa ◽

Advisory Committees ◽

Splenic Enlargement ◽

Hydroxyurea Treatment ◽

Lower Blood ◽

Sub Saharan

Introduction. Children with sickle cell anemia enrolled in Realizing Effectiveness Across Continents with Hydroxyurea (REACH, NCT01966731) received open-label hydroxyurea at maximum tolerated dose (MTD) in four countries within sub-Saharan Africa (Tshilolo et al, NEJM 2019;380:121-131). Unlike children in the United States or Europe, a substantial proportion of REACH participants had splenomegaly at enrollment, and more developed splenomegaly while receiving hydroxyurea. Splenic enlargement in association with hydroxyurea treatment in sub-Saharan Africa is previously unrecognized, and its causes and consequences remain unclear. Methods. Palpable splenomegaly was evaluated at both the mid-clavicular and mid-axillary lines at each scheduled and unscheduled sick visit. The size of the spleen, defined as the greatest distance (cm) below the subcostal margin, was recorded in the REDCap trial database at all four clinical sites. Cross-sectional analysis was performed at baseline enrollment using four spleen categories (Not Palpable, 1-4 cm, ≥5 cm, or Splenectomy) with correlations for age, sex, site, growth parameters, alpha-thalassemia trait and G6PD deficiency. This analysis was repeated using the largest spleen size over the first two years on hydroxyurea, but examining two-year laboratory values and also the hydroxyurea dose at MTD, time to MTD, dose-limiting toxicities, and clinical outcomes including acute splenic sequestration, malaria infections, and sepsis. Results. A total of 606 children started hydroxyurea study treatment, including 6 (1.0%) with previous splenectomy, 59 (9.7%) with previous splenic sequestration, and 99 (16.3%) with palpable splenomegaly at enrollment (52 children with 1-4 cm and 47 with ≥5 cm). Large spleens (≥5 cm) were commonly observed at baseline at all clinical sites except Uganda, which identified only 1 child. Compared to those with no palpable spleen, children with large spleens at baseline had similar age and growth parameters, but were significantly more likely to have alpha-thalassemia (78.7% versus 56.2%, P=0.004) and also G6PD deficiency among males (28.0% versus 17.6%, P=0.32). Children with large spleens at enrollment also had a lower hemoglobin (Hb = 6.5 versus 7.3 g/dL, P<0.001) and lower platelet count (platelets = 227 versus 410 x 109/L, P<0.001), but equivalent fetal hemoglobin (HbF = 10.2 versus 9.4%, P=0.82). On hydroxyurea treatment with escalation to MTD, 262 children (43.7%) had palpable splenomegaly recorded, including 120 (20.0%) with spleens ≥5 cm. These large spleens were observed at all four clinical sites, with DRC having the most (52) and Uganda with the least (14). After 24 months of hydroxyurea treatment, laboratory differences were noted according to the cumulative occurrence of splenomegaly including a significantly lower hemoglobin and platelet count, higher absolute reticulocyte count, and lower hydroxyurea dose at MTD (Table). Large spleens were associated with a high cumulative incidence of laboratory dose-limiting toxicities, as well as a significantly higher risk of having clinically symptomatic malaria and receiving blood transfusions (Table). A total of 31 children (5.2%) on hydroxyurea treatment received elective splenectomy, including one partial splenectomy using arterial embolization. Conclusion. Children with sickle cell anemia living in sub-Saharan Africa have an increased risk of having palpable splenomegaly, which is further increased while receiving hydroxyurea treatment. Large spleen at baseline were associated with lower blood counts, consistent with hypersplenism. On hydroxyurea treatment, children with large spleens had significantly lower blood counts and more dose-limiting toxicities, which lowered their eventual hydroxyurea dose at MTD but still led to robust HbF responses. Children with large spleens were also at higher risk of developing malaria infections, receiving transfusions, and requiring surgical splenectomy. Splenic enlargement in association with hydroxyurea treatment was common in children with sickle cell anemia in the REACH trial; its cause remains unclear but the consequences include substantial laboratory toxicity and clinical morbidity. Investigating the etiologies and management of children with chronically enlarged spleens is crucial before expanding hydroxyurea access across Africa for sickle cell anemia. Disclosures Ware: Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Other: Research Drug Donation; Nova Laboratories: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Membership on an entity's Board of Directors or advisory committees; Novartis: Other: DSMB; Agios: Membership on an entity's Board of Directors or advisory committees; Addmedica: Other: Research Drug Donation.

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Sickle Stroke Screen: A Patient-Centered Educational Initiative for Children with Sickle Cell Anemia in the Displace Consortium

Blood ◽

10.1182/blood-2020-141963 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 43-44

Author(s):

Alyssa M Schlenz ◽

Shannon Phillips ◽

Martina Mueller ◽

Cathy L Melvin ◽

Robert J Adams ◽

...

Keyword(s):

Needs Assessment ◽

Board Of Directors ◽

Sickle Cell ◽

Sickle Cell Anemia ◽

Stroke Prevention ◽

Stroke Risk ◽

Advisory Board ◽

Educational Initiative ◽

Advisory Committees ◽

Board Membership

Introduction: The NHLBI funded Dissemination and Implementation of Stroke Prevention Looking at the Care Environment (DISPLACE) study was designed to improve implementation of stroke prevention guidelines in children with sickle cell anemia (SCA), particularly implementation of transcranial Doppler (TCD) ultrasound for identifying individuals at risk of stroke. The study consists of 3 phases: 1) evaluating current stroke risk screening practices, 2) exploring barriers and facilitators to guideline implementation (needs assessment), and 3) designing and implementing interventions to improve stroke risk screening. A key barrier identified through qualitative methods during the needs assessment was a gap in education, including an overall lack of understanding among patients and caregivers of the purpose of TCD screening. This abstract describes the process of developing one of the interventions for phase 3, a rebranding and educational initiative. Methods: During the needs assessment, 27 key informant interviews and 173 complete surveys were conducted with individuals with SCA and their caregivers. Transcripts from the interviews and survey responses were reviewed to better understand the extent of educational gaps described by families as well as to guide initial rebranding prototypes. Prototypes were developed by the study team, including a new name and logo for TCD as well as an infographic. An interview guide was then created to obtain feedback on the prototypes from individuals with SCA and/or the parent or primary caregiver from two sites in the consortium. Cue cards with prototypes were included with prompts for the "think aloud" method to be applied during interviews. Cue cards were presented first with prototypes for the new name in black font on a white background to solicit feedback on the wording alone. Then, cue cards included various layouts, fonts, and graphics with the prototype names for in-depth feedback on the logo appearance. Finally, participants were asked questions pertaining to the infographic. Results: Twenty interviews were conducted with individuals with SCA and/or the parent/caregiver at two DISPLACE sites. Almost all participants (95%) made the connection between the wording prototypes and TCD without prompting. Many participants expressed that the word "stroke" in both options was "scary," and sometimes chose the option that was "less scary to them." However, many participants also felt that the word "stroke" was necessary to explain the reason for the procedure and would prompt families to ask about the screening as opposed to making them more fearful. The majority of participants (60%) chose "Sickle Stroke Screen" over "Stroke Risk Screen." Participants reported preferring this wording because it is specific to SCA, was easier to remember and represented a less "scary" option. The most commonly preferred logo is presented in Figure 1. Participant reasons for selecting this option were: it is easier to read; they preferred the stacked layout; it is less spread out; they liked the bold letters; it is more eye catching; and it includes the words "sickle cell" in the logo. When asked about preferences for an infographic, the majority described including a picture of a brain. Nearly all participants believed a reassuring message was needed to balance out the fear of the word "stroke." The message, "knowledge is power" provided this balance and resonated with nearly all participants (95%). Figure 2 presents the infographic developed based on participant feedback. Conclusions: Results from this educational rebranding effort highlight the importance of understanding patient and family educational gaps and incorporating their perspective and feedback into educational campaigns. The new logo and infographic were integrated into an educational pamphlet, informative posters and other material designed by the DISPLACE site principal investigators. Part 3 of the study is underway including implementation of the educational initiative at the DISPLACE sites. The new terminology and logo have also been broadly distributed throughout the US through community-based organizations to other patients, families, and stakeholders. Disclosures Kanter: AGIOS: Membership on an entity's Board of Directors or advisory committees; NHLBI Sickle Cell Advisory Board: Membership on an entity's Board of Directors or advisory committees; SCDAA Medical and Research Advisory Board: Membership on an entity's Board of Directors or advisory committees; Wells Fargo: Honoraria; Jeffries: Honoraria; Cowen: Honoraria; bluebird bio, inc: Consultancy, Honoraria; Novartis: Consultancy; Sanofi: Consultancy; Medscape: Honoraria; Guidepoint Global: Honoraria; GLG: Honoraria; BEAM: Membership on an entity's Board of Directors or advisory committees.

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Clonal Tracking By Whole Genome Sequencing Permits Comprehensive Mapping of the Genomic Landscape in Pre- and Post-Gene Therapy Sickle Cell Patients

Blood ◽

10.1182/blood-2021-152262 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 559-559

Author(s):

Alyssa H. Cull ◽

Michael Spencer Chapman ◽

Marioara Ciuculescu ◽

Emily Mitchell ◽

Myriam Armant ◽

...

Keyword(s):

Gene Therapy ◽

Stem Cell ◽

Board Of Directors ◽

Sickle Cell ◽

Research Funding ◽

Phylogenetic Trees ◽

Insertion Site ◽

Advisory Board ◽

Advisory Committees ◽

Genomic Landscape

Abstract Recent advances in clonal stem cell tracking strategies have enabled interrogation of unperturbed human hematopoiesis. Whole genome sequencing (WGS) can be used to map the clonal dynamics of hematopoietic stem and progenitor cells (HSPCs) by employing spontaneous somatic mutations as unique clonal tags (Lee-Six et al., Nature, 2018). These tags allow for retrospective analysis of individual stem cell clones and the construction of phylogenetic trees mapping out stem cell relatedness, with mutations being acquired in a near-linear fashion over the course of an individual's life. The unprecedented level of information obtained in these studies is particularly well-suited to understanding genomic changes in gene therapy trials aimed at curing diseases such as sickle cell disease (SCD). In addition to mapping relatedness between stem cells, sequencing data can be used to better define mutational signatures for HSPC clones that have been successfully gene-modified as well as those that lack an integrated copy of the therapeutic vector. Given this method's ability to identify low frequency mutations in individual HSPC clones, mutations with extremely low variant allele frequencies can be detected much more readily than through traditional bulk sequencing approaches, something that is particularly relevant given recent safety concerns in some SCD gene therapy trials. In this study, we have mapped the clonal dynamics of HSPCs obtained from pre- and post-gene therapy samples from 4 SCD patients who have undergone autologous gene therapy performed using a BCL11A shmiR lentivirus vector (NCT 03282656, 12-36 months follow-up). HSPCs from mobilized peripheral blood (pre-gene therapy), bone marrow aspirates (both pre- and post-gene therapy) or unmobilized peripheral blood (post-gene therapy) were expanded as single clones and 1508 individual colonies were then sequenced using WGS to an average sequencing depth of 12.3x. Initial results indicate that the mean mutation burden per cell in a pre-gene therapy sample is elevated for some patients compared to what would be expected based on patient age in similar studies. In pre-gene therapy samples, the structure of the phylogenetic trees appeared to be highly polyclonal, indicating that there were no significant clonal expansion events prior to gene therapy. In one patient where we undertook extensive profiling, approximately 15-20 excess mutations per HSPC were observed across the entire genome 24 months after transplantation, presumably acquired as a consequence of gene therapy and/or reconstitution post-transplantation, which is equivalent to approximately one year of normal ageing without a transplantation intervention. However, no clonal expansions or driver mutations were identified at this 24 month follow-up timepoint, suggesting that no strong selective advantage or pre-leukemic events were present prior to or following the gene therapy protocol. Extending this approach to a wider range and larger number of patients will allow for comprehensive mapping of the genomic landscape and clonal evolution of stem cells in sickle cell patients and will also set the stage for improved assessment of safety and potential leukemia-initiating events in the context of gene therapy. Disclosures Esrick: bluebird bio: Consultancy. Williams: bluebird bio: Membership on an entity's Board of Directors or advisory committees, Other: Insertion Site Analysis Advisory Board, Patents & Royalties: BCH licensed certain IP relevant to hemoglobinopathies to bluebird bio. The current license includes the potential for future royalty/milestone income. Bluebird has indicated they will not pursue this as a clinical program and BCH is negotiating return of, Research Funding; BioMarin: Membership on an entity's Board of Directors or advisory committees, Other: Insertion Site Advisory Board; Beam Therapeutics: Membership on an entity's Board of Directors or advisory committees, Other: Scientific Advisory Board; Emerging Therapy Solutions: Membership on an entity's Board of Directors or advisory committees, Other: Chief Scientific Chair; Geneception: Membership on an entity's Board of Directors or advisory committees, Other: Scientific Advisory Board; Alerion Biosciences: Other: Co-founder (now licensed to Avro Bio, potential for future milestones/royalties); Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Steering Committee, Novartis ETB115E2201 (eltrombopag in aplastic anemia). Advisory fees donated to NAPAAC.; Orchard Therapeutics: Membership on an entity's Board of Directors or advisory committees, Other: Membership on a safety advisory board (SAB): SAB position ended 05/20/2021. Co-founder , Patents & Royalties: Potential for future royalty/milestone income, X-SCID. Provided GMP vector for clinical trial, Research Funding. Campbell: Mu Genomics: Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees. Kent: STRM.bio: Research Funding.

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Clinical and Biomarker Predictors for Avascular Necrosis in Sickle Cell Disease

Blood ◽

10.1182/blood-2021-147829 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3091-3091

Author(s):

Michael Rabaza ◽

Maria Armila Ruiz ◽

Liana Posch ◽

Faiz Ahmed Hussain ◽

Franklin Njoku ◽

...

Keyword(s):

Risk Factors ◽

Sickle Cell Disease ◽

Board Of Directors ◽

Avascular Necrosis ◽

Sickle Cell ◽

Research Funding ◽

Medical Attention ◽

Cell Disease ◽

Advisory Committees ◽

Early Management

Abstract Introduction Sickle cell disease (SCD) affects 1 in 365 African Americans and approximately 25 million people world-wide. A common skeletal system complication is avascular necrosis (AVN), which can cause substantial pain and a reduced quality of life. While early management of AVN is focused on increasing range of motion with physical therapy and pain relief, there are no clear predictors for who is more likely to develop AVN and earlier institution of these preventive measure could help decrease disease progression. Vascular endothelial growth factor (VEGF) is a biomarker of endothelial injury and may indicate reduced vascular supply to the femoral or humeral head. Here we describe potential risk factors and biologic pathways for AVN in SCD, as understanding these may lead to improvements in future monitoring, early detection, and early intervention practices. Methods We investigated clinical and laboratory risk factors associated with AVN in a cohort of 435 SCD patients from our center. Blood samples, clinical, and laboratory data were collected at the time of enrollment during a clinic visit. Genotyping for alpha thalassemia was performed by PCR and the serum concentration of VEGF was measured by ELISA. AVN status was confirmed by review of the medical record and available imaging. We conducted a cross-sectional analysis comparing categorical and linear variables by AVN status using the chi-square and Kruskal-Wallis test, respectively. The independent association of the clinical and laboratory variables with AVN status was determined by logistic regression analysis. The initial model included variables with a P-value < 0.1 on univariate analysis and the final model was ascertained by stepwise forward and backward selection. Median values and interquartile range (IQR) are provided. Results The median age of the cohort was 32 (IQR, 24 - 43) years, 57% (250/435) were female, and 46% (198/435) were on hydroxyurea. AVN was observed in 34% (149/435) of SCD patients. SCD patients with AVN were older, had more frequent vaso-occlusive crises requiring medical attention, and had a higher body mass index (Table I) (P ≤ 0.002). We measured VEGF in 241 of the SCD patients with serum samples available at the time of enrolment. Serum VEGF concentrations trended higher in SCD patients with versus without AVN (420 vs. 359 pg/mL, respectively; P = 0.078). In the multivariate analysis model, AVN was independently associated with increased number of vaso-occlusive crises (OR 1.1, 95% CI: 1.0 - 1.14; P = 0.02), AST concentration (natural log OR 0.5, 95% CI: 0.2 - 0.9; P = 0.03), VEGF concentration (natural log OR 1.4, 95% CI: 1.0 - 1.9; P = 0.047), and tobacco use (OR 1.9, 95% CI: 0.9 - 3.7; P = 0.078). Discussion In conclusion, we demonstrate a high prevalence of AVN in an adult cohort of SCD patients. The presence of AVN was independently associated with a greater frequency of vaso-occlusive pain episodes, which may demonstrate a shared pathophysiology between AVN and vaso-occlusion that merits further investigation. We demonstrate that serum VEGF concentrations are higher in SCD patients with AVN and may be a clinical tool to identify those at high-risk and for earlier intervention for this complication. Figure 1 Figure 1. Disclosures Gordeuk: Modus Therapeutics: Consultancy; Novartis: Research Funding; Incyte: Research Funding; Emmaus: Consultancy, Research Funding; Global Blood Therapeutics: Consultancy, Research Funding; CSL Behring: Consultancy. Saraf: Pfizer: Research Funding; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Predictors of Maternal Morbidity Among Participants Enrolled in the Sickle Cell Disease Implementation Consortium Registry

Blood ◽

10.1182/blood-2020-140743 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 3-3

Author(s):

Rita V Masese ◽

Dominique Bulgin ◽

Liliana Preiss ◽

Mitchell Knisely ◽

Eleanor Stevenson ◽

...

Keyword(s):

Board Of Directors ◽

Sickle Cell ◽

Research Funding ◽

Transfusion Requirement ◽

The United States ◽

Acute Chest Syndrome ◽

Maternal Outcomes ◽

Maternal Complications ◽

Advisory Committees ◽

Increased Risk

Introduction Pregnancy in sickle cell disease (SCD) is associated with an exacerbation of SCD-related complications and an increased risk of maternal complications. The increased risk is partly due to physiologic adaptations in pregnancy, which include increased metabolic demands and a hypercoagulable state. The maternal death rate for SCD is 629 per 100,000 deliveries, compared to 12 per 100,000 deliveries in black women and 6 per 100,000 deliveries in the general population (Raider et al., 2016). Studies on maternal and perinatal outcomes of patients with SCD present inconsistent and conflicting results. Some studies have reported an increase in maternal complications such as pre-eclampsia, acute chest syndrome and thromboembolic events, while other studies have reported no significant risk in adverse maternal outcomes. The inconsistent findings reported in prior studies may be attributed to small sample sizes and single-centered sites. Our study aims to determine the prevalence and predictors of maternal morbidity among participants enrolled in the SCD Implementation Consortium (SCDIC) registry, which is the largest, most geographically diverse SCD participant sample in the United States. Methods This cross-sectional study included women enrolled in the SCDIC registry who had at least one pregnancy event. The SCDIC is composed of eight academic SCD centers across the United States and one data-coordinating center. Participants were enrolled in the SCDIC registry if they were 18 to 45 years of age and had a confirmed diagnosis of SCD. Enrolled participants completed a series of surveys that collected sociodemographic information, SCD and pregnancy history and data abstractions of participants' medical records was completed. Medical complications queried during pregnancy included: vaso-occlusive episodes, acute chest syndrome, blood transfusion requirement, preeclampsia, maternal diabetes and deep venous thrombosis. Descriptive analysis of sociodemographic, clinical and maternal characteristics was conducted. Bivariate analysis was performed using Chi-Square test, Mann-Whitney U test, t-test, and logistic regressions, as appropriate. A p-value of ≤ 0.05 was considered statistically significant for all analysis. Results The study sample included 743 women who had at least one pregnancy event, and a total of 1066 live births. Almost all women (96.3%) were African American, with a median age of 21 years (inter-quartile range of 19 to 23 years) at first birth. The majority had Hb SS SCD genotype (69.5%; 513 of the 738 with SCD genotype data). Of all reported pregnancies, participants did not use hydroxyurea during conception (78%), and pregnancy (84.5%). Only 2.7 % of the women reported using fertility drugs or assisted reproductive procedures. Seventy five percent of the pregnancies that ended in live births had maternal complications. The leading complications were vaso-occlusive episodes (61.2%), pregnancy requiring blood transfusion(s) (33.2%), preeclampsia (15.4%), deep venous thrombosis (5.6%) and acute chest syndrome (7.7%). When the pregnancies were stratified by SCD genotype, women with Hb SS had a higher occurrence of acute chest syndrome (63.4% vs. 26.7%), transfusion requirement (70.8% vs. 21%) and preeclampsia (66.7% vs 22.4%). In the univariate logistic regressions, multiparous women, with a history of adverse maternal outcomes in a previous pregnancy, had higher odds of vaso-occlusive episodes (OR: 3.42; 95% CI: 2.42-4.94) acute chest syndrome (OR:4.99; 95% CI:2.56- 9.48), transfusion requirement (OR:3.86; 95% CI:2.64- 5.69), and pre-eclampsia (OR:3.36; 95% CI:2.05-5.45). Conclusion In this large multicenter registry, we found pregnant women with SCD have significant maternal complications. Early antenatal care by healthcare providers knowledgeable about risk factors for adverse maternal outcomes in SCD is essential improve maternal and fetal outcomes and reduce the maternal death rate for SCD. Disclosures Hankins: Novartis: Research Funding; Global Blood Therapeutics: Consultancy, Research Funding; MJH Life Sciences: Consultancy, Patents & Royalties; UptoDate: Consultancy; National Heart, Lung, and Blood Institute: Honoraria, Research Funding; LINKS Incorporate Foundation: Research Funding; American Society of Pediatric Hematology/Oncology: Honoraria. Treadwell:Global Blood Therapeutics: Consultancy; UpToDate: Honoraria. King:Amphivena Therapeutics: Research Funding; Bioline: Consultancy; Celgene: Consultancy; Cell Works: Consultancy; Incyte: Consultancy; Magenta Therapeutics: Membership on an entity's Board of Directors or advisory committees; Novimmune: Research Funding; RiverVest: Consultancy; Tioma Therapuetics: Consultancy; WUGEN: Current equity holder in private company. Gordeuk:CSL Behring: Consultancy, Research Funding; Global Blood Therapeutics: Consultancy, Research Funding; Imara: Research Funding; Ironwood: Research Funding; Novartis: Consultancy. Kanter:SCDAA Medical and Research Advisory Board: Membership on an entity's Board of Directors or advisory committees; AGIOS: Membership on an entity's Board of Directors or advisory committees; BEAM: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy; GLG: Honoraria; Jeffries: Honoraria; Cowen: Honoraria; Wells Fargo: Honoraria; NHLBI Sickle Cell Advisory Board: Membership on an entity's Board of Directors or advisory committees; Medscape: Honoraria; Guidepoint Global: Honoraria; bluebird bio, inc: Consultancy, Honoraria; Sanofi: Consultancy. Glassberg:Pfizer: Research Funding; Global Blood Therapeutics: Consultancy; Eli Lilly and Company: Research Funding. Shah:Novartis: Consultancy, Research Funding, Speakers Bureau; Alexion: Speakers Bureau; CSL Behring: Consultancy; Bluebird Bio: Consultancy; Global Blood Therapeutics: Consultancy, Research Funding, Speakers Bureau.

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