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New treatments directly targeting polymerization of sickle hemoglobin (HbS), the proximate event in the pathophysiology of sickle cell disease (SCD), are needed to address the severe morbidity and early mortality associated with the disease. Voxelotor (GBT440) is a first-in-class oral therapy specifically developed to treat SCD by modulating the affinity of hemoglobin (Hb) for oxygen, thus inhibiting HbS polymerization and downstream adverse effects of hemolytic anemia and vaso-occlusion. GBT440-001 was a phase 1/2 randomized, double-blind, placebo-controlled, single and multiple ascending dose study of voxelotor in adult healthy volunteers and patients with SCD, followed by a single-arm, open-label extension study. This report describes results of voxelotor (500-1000 mg per day) in patients with sickle cell anemia. The study evaluated the safety, tolerability, pharmacokinetic, and pharmacodynamic properties of voxelotor and established proof of concept by improving clinical measures of anemia, hemolysis, and sickling. Thirty-eight patients with SCD received 28 days of voxelotor 500, 700, or 1000 mg per day or placebo; 16 patients received 90 days of voxelotor 700 or 900 mg per day or placebo. Four patients from the 90-day cohort were subsequently enrolled in an extension study and treated with voxelotor 900 mg per day for 6 months. All patients who received multiple doses of voxelotor for ≥28 days experienced hematologic improvements including increased Hb and reduction in hemolysis and percentage of sickled red cells, supporting the potential of voxelotor to serve as a disease-modifying therapy for SCD. Voxelotor was well tolerated with no treatment-related serious adverse events and no evidence of tissue hypoxia. These trials were registered at www.clinicaltrials.gov as #NCT02285088 and #NCT03041909.

There are over 12,000 people with sickle cell disease (SCD) in the UK, and 4-12% of patients who develop Sickle Cell Nephropathy (SCN) progress to End Stage Renal Disease (ESRD). Renal transplantation offers the best outcomes for these patients with but their access to transplantation is often limited. Regular automated exchange blood transfusions (EBT) reduce the complications of SCD and may improve outcomes. However, concerns over alloimmunisation limit its widespread implementation. In this retrospective multicenter study, data were collected on 34 SCD patients who received a kidney transplant across 6 London Hospitals between 1997 and 2017. 20/34 patients were on an EBT program, pre or post renal transplantation. Overall patient and graft survival were inferior to contemporaneous UK data in the ESRD population as a whole, a finding which is well-recognised. However, patient survival (CI 95%, p = 0.0032), graft survival and graft function were superior at all time-points in those who received EBT versus those who did not. 4/20 patients (20%) on EBT developed de novo donor specific antibodies (DSAs). 3/14 patients (21%) not on EBT developed de novo DSAs. The incidence of rejection in those on EBT was 5/18 (28%), as compared with 7/13 (54%) not on EBT. In conclusion, our data, while limited by an inevitably small sample size and differences in the date of transplantation, do suggest that long-term automated EBT post renal transplant is effective and safe, with improvement in graft and patient outcomes and no increase in antibody formation or graft rejection.

Additional file 1. SPIRIT 2013 Checklist: Recommended items to address in a clinical trial protocol and related documents.

Background Sickle cell disease (SCD) is a multisystem disease, and the predominant articular manifestation is osteonecrosis (ON). Total hip arthroplasty (THA) is technically challenging, and the complication rates are high. In this retrospective study, we have analysed the outcome of THA in a cohort of patients with SCD at our institution. Materials and methods We identified 34 THAs between 1999 and 2016 in 30 patients (mean age 37 years) from our SCD database. Co-morbidities, both sickle and non-sickle-related, were documented. Complications and indications for revision surgery were analysed. Results An uncemented prosthesis was predominantly used. The mean follow-up was 10.5 years (range 1–18). Six patients had revision surgery (17.6%), 2 (5.8%) for Prosthetic Joint Infection (PJI), and 4 (11.7%) for osteolysis of the acetabular component. Conclusion Our revision rates were comparable to the published literature. Our combined sickle cell clinic and the coordinated multidisciplinary management have been successful in reducing morbidity.

ObjectiveThe purpose of this retrospective cross-sectional study was to investigate whether changes in white matter integrity are related to slower processing speed in sickle cell anemia.MethodsThirty-seven patients with silent cerebral infarction, 46 patients with normal MRI, and 32 sibling controls (age range 8–37 years) underwent cognitive assessment using the Wechsler scales and 3-tesla MRI. Tract-based spatial statistics analyses of diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) parameters were performed.ResultsProcessing speed index (PSI) was lower in patients than controls by 9.34 points (95% confidence interval: 4.635–14.855,p= 0.0003). Full Scale IQ was lower by 4.14 scaled points (95% confidence interval: −1.066 to 9.551,p= 0.1), but this difference was abolished when PSI was included as a covariate (p= 0.18). There were no differences in cognition between patients with and without silent cerebral infarction, and both groups had lower PSI than controls (bothp< 0.001). In patients, arterial oxygen content, socioeconomic status, age, and male sex were identified as predictors of PSI, and correlations were found between PSI and DTI scalars (fractional anisotropyr= 0.614,p< 0.00001;r= −0.457,p< 0.00001; mean diffusivityr= −0.341,p= 0.0016; radial diffusivityr= −0.457,p< 0.00001) and NODDI parameters (intracellular volume fractionr= 0.364,p= 0.0007) in widespread regions.ConclusionOur results extend previous reports of impairment that is independent of presence of infarction and may worsen with age. We identify processing speed as a vulnerable domain, with deficits potentially mediating difficulties across other domains, and provide evidence that reduced processing speed is related to the integrity of normal-appearing white matter using microstructure parameters from DTI and NODDI.

We explored transient elastography (TE) and enhanced liver fibrosis (ELF™ ) score with standard markers of liver function to assess liver damage in 193 well patients with sickle cell disease (SCD). Patients with HbSS or HbSβ0 thalassaemia (sickle cell anaemia, SCA; N = 134), had significantly higher TE results and ELF scores than those with HbSC (N = 49) disease (TE, 6·8 vs. 5·3, P

Sickle cell disease (SCD) is a multisystem disease, in which pregnancy carries significant risks of maternal and perinatal morbidity and mortality. Women with SCD should have their pregnancies managed jointly by specialist obstetricians, midwives and haematologists. Within the UK, there is great geographical variation in the prevalence of SCD, with the highest prevalence in large urban centres. Trainee obstetricians practising outside these areas may not gain substantial experience in managing these patients and this review therefore aims to highlight the antenatal, intrapartum and postnatal management of pregnant women with SCD.

Fetal hemoglobin (HbF) is a strong modifier of sickle cell disease (SCD) severity and is associated with 3 common genetic loci. Quantifying the genetic effects of the 3 loci would specifically address the benefits of HbF increases in patients. Here, we have applied statistical methods using the most representative variants: rs1427407 and rs6545816 in BCL11A , rs66650371 (3-bp deletion) and rs9376090 in HMIP-2A , rs9494142 and rs9494145 in HMIP-2B , and rs7482144 ( Xmn 1- HBG2 in the β-globin locus) to create g(HbF ) , a genetic quantitative variable for HbF in SCD. Only patients aged ≥5 years with complete genotype and HbF data were studied. Five hundred eighty-one patients with hemoglobin SS (HbSS) or HbSβ 0 thalassemia formed the “discovery” cohort. Multiple linear regression modeling rationalized the 7 variants down to 4 markers ( rs6545816 , rs1427407 , rs66650371 , and rs7482144 ) each independently contributing HbF-boosting alleles, together accounting for 21.8% of HbF variability ( r 2 ) in the HbSS or HbSβ 0 patients. The model was replicated with consistent r 2 in 2 different cohorts: 27.5% in HbSC patients (N = 186) and 23% in 994 Tanzanian HbSS patients. g(HbF) , our 4-variant model, provides a robust approach to account for the genetic component of HbF in SCD and is of potential utility in sickle genetic and clinical studies.

To the editor: Survival of patients with sickle cell disease (SCD) in high-income countries has improved greatly in the last 60 years. In 1960, it was described as a “disease of childhood”[1][1] whereas 25 years later, the Cooperative Study of Sickle Cell Disease reported that 85% of hemoglobin

Transfusion of red blood cells is a major therapeutic option in sickle cell disease (SCD). There is strong evidence for its efficacy, particularly in primary and secondary stroke prevention in children, however, its use in other areas remains controversial. This study assessed the patterns of transfusion in the adult cohort attending King's College Hospital over a 10-year period, from 2000 to 2009. Total blood usage has increased significantly (P = 0·006) during this time, with 78% of the blood received by only 6% of the patients. The increase is explained by increased automated red cell exchange and increased usage for planned and acute transfusions for sickle-related complications.

Patients with sickle cell disease (SCD) are perceived to have a high mortality when admitted to critical care. We performed a retrospective analysis of all adult sickle admissions to Critical Care Unit (CCU) at a single centre over an eight year period between 1 January 2000 to 31 December 2007. Thirty eight patients (14 male) were admitted 46 times to CCU; the commonest reasons for admission were acute chest syndrome (14, 30%), multi-organ failure (8, 17%) and planned post-elective surgery (7, 15%). CCU mortality for patients with SCD was 19.6%, comparable to a CCU-wide mortality of 17.6% during the study period in the same institution. Re-admission to critical care was high (16% over the eight year period) but did not increase mortality risk.

Free circulating DNA is present in the plasma of healthy subjects, and is elevated in conditions characterized by increased cell death, such as cancer and physical trauma. Analysis of circulating DNA in plasma could provide a useful biomarker in sickle cell disease (SCD) in view of the increased cell turnover through chronic ongoing haemolysis, recurrent vaso-occlusion and inflammation. Plasma DNA was determined by real-time quantitative polymerase chain reaction (PCR) amplification of the beta-globin gene (HBB) in 154 patients with SCD [105 haemoglobin (Hb)SS, 46 HbSC and three HbS/beta(0) thalassaemia] and 53 ethnically matched controls. Blood samples were obtained from all patients in steady state; 21 of the 154 patients were also sampled during admission to hospital for acute pain. Median concentration of circulating plasma DNA in acute pain was more than 10-fold that in steady state and in controls - 10070 vs. 841 and 10070 vs. 933 genome equivalents/ml respectively (P < 0.0001, in both cases). During steady state, patients had plasma DNA levels similar to controls. Plasma DNA levels in SCD correlated with C-reactive protein levels (P < 0.005) and total white cell counts (P < 0.05) in steady state. The study shows that plasma DNA concentration may have potential as a biomarker in sickle cell patients.

Serum bilirubin levels and predisposition to gallstones in sickle cell disease (SCD) are influenced by genetic variation in the hepatic uridine diphosphate (UDP)-glucuronosyltransferase (UGT1A1) gene, but the association is not consistent. This study investigated whether variation in the gene encoding haem oxygenase (HMOX1), a rate-limiting enzyme upstream of UGT1A in the haem catabolic pathway, and alpha-thalassaemia could explain some of the inconsistent effects. The UGT1A1 [TA](n) and HMOX1 [GT](n) promoter polymorphisms and alpha globin genotypes were determined in 263 SCD patients (199 HbSS, 5 HbS/beta(0), 59 HbSC). Detection of gallstones was based on ultrasound of the liver/biliary tree. Regression analysis showed that serum bilirubin levels and the incidence of gallstones were strongly associated with the number of UGT1A1 [TA] repeats in all subjects (P < 0.0001 and P < 0.01, respectively). While HMOX1 genotype had no effect, co-inheritance of alpha-thalassaemia reduced serum bilirubin levels in all SCD patients independently of the number of UGT1A1 [TA] repeats. Each additional [TA] repeat is associated with an increase in mean serum bilirubin levels of 21% and cholelithiasis risk of 87% in SCD.

1. Department of Haematology, Guy’s and St Thomas’ NHS Foundation Trust 2. Lane Fox Respiratory Unit, St Thomas’ Hospital, Guy’s and St Thomas’ NHS Foundation Trust 3. Department of Haematology, North Middlesex Hospital 4. Department of Paediatric Haematology, Bristol Royal Hospital for Children 5. Department of Haematological Medicine, King’s College Hospital 6. Department of Haematology, Whittington Hospital

Hydroxyurea is increasingly used in the treatment of sickle cell disease (SCD) although there is little evidence on how best to monitor treatment and compliance. It is also not known why 10-50% patients do not benefit from the drug and whether some of this resistance is because of pharmacokinetic factors. We have developed an assay using mass spectrometry (MS) to measure urinary concentrations of hydroxyurea. We have used this assay to study 12 children and six adults with SCD taking hydroxyurea and found that urinary hydroxyurea was present for at least 12 h following tablet ingestion. Thirty-five urine samples were analysed that were expected to contain hydroxyurea, based on the reported timing of the last dose and hydroxyurea was detected in 29 (83%) of these. There were also marked differences in urinary hydroxyurea concentrations, suggesting pharmacokinetic variability may explain some of the differences in response to hydroxyurea. Urine samples were also analysed by MS for penicillin metabolites and 43 of the 57 (75%) contained phenoxyacetate, suggesting the ingestion of penicillin within the last 12 h. These assays are potentially useful to study hydroxyurea metabolism further, develop optimal dosing regimes and monitor compliance with treatment.

Hydroxyurea reduces the frequency of acute pain in sickle cell disease (SCD). We sought to determine if hydroxyurea therapy affects cell free DNA (cfDNA) levels in SCD. cfDNA levels fell in all 10 patients studied; before hydroxyurea, mean was 1,879 (95% CI 1,104-3,199) GE/mL; after hydroxyurea, mean was 780 (95% CI, 634-959) GE/mL (P = 0.002). Mean cfDNA level in the 10 HbSS adults prior to starting hydroxyurea was also significantly higher than that in 115 HbSS case controls who had never taken hydroxyurea (1,879 vs 975 GE/mL, P = 0.02). cfDNA levels may be useful in monitoring response to hydroxyurea therapy in SCD.

Background: Sickle cell disease (SCD) is caused by polymerization of Hemoglobin S (HbS), resulting in hemolysis and vaso-occlusion. No therapy achieving pancellular, direct inhibition of HbS polymerization is available. GBT440 is a novel small molecule which increases hemoglobin oxygen affinity and inhibits HbS polymerization and prevents sickling in vitro. This study explored safety, pharmacokinetics (PK) and pharmacodynamics (PD) of GBT440 in healthy volunteers (HV) and subjects with SCD. Methods: This randomized, placebo-controlled, double-blind, phase I/II study enrolled HV and SCD subjects (HbSS and HbSB0). A cohort of 8 subjects with other SCD genotypes (HbSC or HbS/β+thalassemia) is being enrolled. The study was conducted in three parts: Part A, single ascending doses, Part B, multiple ascending doses for 28 days and Part C, 90-day dosing. Longer term dosing (up to 6 months) is being evaluated. The primary endpoint was safety. Secondary endpoints included PK, PD and hematological effects. Results: New and updated results including up to 6 months of dosing and data on other SCD genotypes will be presented at the meeting. As of 26 July 2016, 38 SCD subjects had completed Part B (10 at 500 mg; 12 at 700 mg; 6 at 1000 mg; 10 received placebo [pbo]). An additional 16 SCD subjects have completed or are ongoing in Part C (6 at 700 mg: 6 at 900 mg; 4 on pbo). Enrollment is ongoing for SCD subjects with HbSC or HbS/β+thalassemia. Results are available for SCD subjects enrolled into Part B and Part C (700 mg). The SCD subjects include approximately 60% male, 40% female; 20% were on hydroxyrea (HU); 20% had 2 or more painful crises requiring hospitalization in the prior year; median age was 34 years (range, 20 to 56). There were no drug-related severe or serious adverse events; the majority of AEs were Grade 1 or 2. The most common treatment emergent AEs were headache, back pain and sickle cell crisis. All sickle cell crises on placebo or GBT440 occurred off treatment and were assessed as not related to study drug. PK exposures increased dose-proportionally; mean GBT440 whole blood half-life following multiple doses was approximately 1.5 days and RBC:plasma ratio was 75:1. GBT440-treated subjects demonstrated increased hemoglobin oxygen affinity (p50 shifted to the left towards the normal range), an increase in hemoglobin levels and a sustained decrease in unconjugated bilirubin during the 90 day treatment period (Figure 1, Table 1). Other markers of hemolysis improved concordantly (Table 1). Conclusions: GBT440 was well tolerated with dose-proportional PK and increases in hemoglobin oxygen affinity. GBT440 resulted in marked and sustained reduction in clinical markers of hemolysis and an increase in hemoglobin. These results are consistent with inhibition of HbS polymerization leading to decreased RBC damage, improved RBC lifespan and tissue oxygen delivery, and support further investigation of GBT440 as a potential disease-modifying therapy for SCD. Change from Baseline to Day 90 in Hemoglobin (GBT440 700 mg) Change from Baseline to Day 90 in Hemoglobin (GBT440 700 mg) Figure 1 Figure 1. Disclosures Lehrer-Graiwer: Global Blood Therapeutics: Employment, Equity Ownership. Mant:Quintiles: Employment. Dufu:Global Blood Therapeutics: Employment, Equity Ownership. Hutchaleelaha:Global Blood Therapeutics: Employment, Equity Ownership. Oksenberg:Global Blood Therapetics: Employment, Equity Ownership. Patel:Global Blood Therapeutics: Employment, Equity Ownership. Tonda:Global Blood Therapetics: Employment, Equity Ownership. Bridges:Global Blood Therapetics: Employment, Equity Ownership. Ramos:Global Blood Therapeutics: Employment, Equity Ownership.

Fetal hemoglobin (HbF) is strongly associated with clinical severity in the β-hemoglobinopathies, including sickle cell disease (SCD). In recent years, the three major HbF genetic loci (at BCL11A on chromosome 2p, HMIP-2 on chromosome 6q and Xmn1-HBG on chromosome 11p) have been more clearly characterized and mechanisms of the likely causal variants better defined. In this study, we have combined this new biological understanding with statistical methods to create a genetic "predictor" for HbF in SCD. We chose 7 variants to represent the 3 HbF quantitative trait loci (QTL) to investigate their utility in predicting HbF levels, and, in turn, clinical severity of SCD. For BCL11A, we used 2 markers: rs1427407 (62kb downstream of BCL11A) localizes to an erythroid-specific enhancer (Bauer et al. Science 2013) and rs6545816 tags a second signal 58kb downstream of BCL11A. The genetic architecture of HMIP-2 as a QTL comprises two elements, A and B (Menzel et al. Ann Hum Genet 2014). We have represented HMIP-2A withthe 3bp deletion rs66650371, shown as a causal variant (Stadhouders et al. JCI 2014) plus the ethnicity marker rs9376090. HMIP-2B is less well-characterized, we selected: rs9494142 (near the MYB enhancer) and rs9494145. For the β-globin locus, we used the long-established Xmn1 marker (rs7482144) in the proximal promoter 158kb upstream of HBG2. This is likely not the variant itself, but in tight linkage disequilibrium with the causal element. Of 892 initial patients (516 females, 376 males), we excluded 17 children aged under 5 because of the non-linear relationship between age and HbF at a young age (we confirmed this finding in our cohort). This left: 658 with HbSS, 206 with HbSC, 8 with HbSβ0 thalassemia, and 20 with HbSβ+ thalassemia. We then genotyped 666 patients with HbSS/HbSβ0 thalassemia for the 7 genetic variants. For each patient, we selected 'validated' HbF levels i.e. HbF not influenced by transfusion, drugs (especially hydroxyurea) or pregnancy. HbF levels were log-transformed (Ln). We then used multiple linear regression models to identify variants which were independently associated with Ln-HbF levels. Using only age and sex as covariates revealed predictive power r2~10% which was orthogonal to (i.e. additive) the predictive power of the variants, and so we did not include them in subsequent analysis. Also, by adding α-globin status to the model where known (N=272), the r2 remained unchanged and is not significant for α-globin status. We then normalized the 7 variants to take account of the mean allele count (a strongly predictive but rare variant may not explain much of the total population variance). We performed multiple linear regression to rationalize the 7 variants, and found 4 markers (rs6545816, rs1427407, rs66650371 and rs7482144) independently contributing HbF-boosting alleles (see table). Combining these 4 variants into a genetic risk model, as per the table, allows us to predict 21.8% of variability (r2) of HbF in our HbSS / HbSβ0 thalassemia patients. We validated the 4-variant risk score first with a 5-fold cross-validation within the cohort which demonstrated a mean r2=22% for the 5 folds. We then replicated the findings in the cohort of HbSC patients (N=206) and found the 4-variant model to predict HbF with variability r2=27.5% (i.e. towards r2=44% seen in non-anemic individuals). Thus, our 4-variant model provides a robust approach to genetic prediction of HbF in SCD. The predictive power appears to be larger for HbSC compared to HbSS (r2=27.5% vs 21.8%) which may be related to stress erythropoiesis in HbSS patients releasing immature erythrocytes as a non-genetic factor modifying HbF levels. This process is a first step towards creating a global genetic predictive score in SCD: stratifying patients with SCD early in life would enable us to offer curative therapy (i.e. hematopoietic stem cell transplant) to those identified as genetically severe. Disclosures No relevant conflicts of interest to declare.

Transfusion of red blood cells is a major therapeutic option in sickle cell disease (SCD). There is strong evidence for its efficacy, particularly in primary and secondary stroke prevention in children, however, its use in other areas remains controversial. This study assessed the patterns of transfusion in the adult cohort attending King's College Hospital over a 10-year period, from 2000 to 2009. Total blood usage has increased significantly (P = 0·006) during this time, with 78% of the blood received by only 6% of the patients. The increase is explained by increased automated red cell exchange and increased usage for planned and acute transfusions for sickle-related complications.

Sickle cell disease (SCD) patients are perceived to have a high mortality when admitted to the Critical Care Unit (CCU). We performed a retrospective analysis of all adult sickle admissions to CCU at a single centre over an 8-year period (1 January 2000 to 31 December 2007). Thirty-eight patients (14 male) were admitted 46 times to CCU; the commonest reasons for admission were acute chest syndrome (14, 30%), multi-organ failure (8, 17%) and planned post-elective surgery (7, 15%). CCU mortality for SCD patients was 19.6%, comparable to a CCU-wide mortality of 17.6% during the study period in the same institution. Re-admission to CCU was high (16% over the 8-year period) but did not increase mortality risk.

Acute Human Parvovirus B19 (HPV B19) infection is the major cause of transient red cell aplasia (TRCA) and acute anaemia in patients with sickle cell disease (SCD). We report three cases of patients who developed nephrotic syndrome (NS) with chronic sequelae after initially presenting with HPV B19-associated TRCA. There was no correlation between evidence of HPV B19 infection and impaired renal function in our cohort of adult sickle cell patients. This is consistent with a view that although NS is potentially a rare complication of symptomatic acute HPV B19 infection, exposure to HPV B19 is not associated with an increased risk of renal disease.

Complications affecting multiple organs, including the liver, contribute to early mortality in patients with sickle cell disease (SCD). Earlier diagnosis and monitoring of "sickle hepatopathy", preferably using non-invasive methods, would enable earlier intervention and therefore, potentially a better outcome for patients. In many non-SCD chronic liver diseases, fibrosis stage is the most important predictor of morbidity and mortality. Two non-invasive methods of assessing liver fibrosis are used: Transient Elastography (TE, Echosens) and Enhanced Liver Fibrosis Score™ (ELF, iQUR). TE detects fibrosis using ultrasound and low frequency elastic waves with a propagation velocity directly related to the stiffness of the liver. The ELF score examines the balance between matrix deposition and degradation using levels of three proteins analysed using a patented formula. We report a prospective study correlating liver function tests (LFTs) with the level of liver fibrosis (as ascertained by TE and ELF) in a cohort of patients with SCD. Ethical approval for this study was obtained from the NHS ethics committee (11/LO/0005) and patients were consecutively recruited in the steady-state sickle cell clinic at Kings' College Hospital, London, during 2012. Patients were excluded if they had viral hepatitis or were pregnant. Clinical (transfusion and hydroxyurea therapy), imaging (liver iron concentration, LIC) and laboratory data were collected during steady-state. TE and ELF were performed on 194 patients. The patients ranged from 17-72 years (mean age 35 years); 78 (40%) were male, 134 (68%) had HbSS or HbSb0 (SCA), 48 (26%) Hb SC, and the remainder, Hb Sβ+ (excluded due to low numbers). Statistical analysis was undertaken in IBM SPSS version 20. There was significant correlation between both TE and ELF with age, when corrected for sickle genotype (TE β = 0.19, p = 0.006 and ELF β = 0.2, p = 0.005) (Figure). Patients with SCA had significantly higher TE results and mean ELF scores than those with HbSC (TE, 6.8 vs 5.3, p In SCA patients, TE correlated significantly with all serum LFTs (Albumin R = -0.35 p In SCA patients, ELF score correlated with serum LFTs (Albumin R = -0.30 p These data show significant levels of liver dysfunction in our SCD population using both TE and ELF score which correlated significantly with abnormal LFTs and markers of hemolysis and iron overload. The role of TE and ELF in monitoring liver dysfunction in SCD needs to be further validated, preferably with longitudinal, and if possible histological data. Table 1. Range and mean TE results and ELF score for whole cohort and subgroups. Whole cohort n = 194 (%) SCA n = 134 (%) Hb SC n = 48 (%) p value FibroScan results (kPa) Mean (range) 6.3 (2.0 - 21.3) 6.8 (2.0 - 21.3) 5.3 (2.0 - 16.0) < 0.0001 None/mild (0-7.65) 153 (79) 98 (73) 43 (90) Moderate (7.66-13.00) 33 (17) 29 (22) 4 (8) Severe (≥13.01) 8 (4) 7 (5) 1 (2) ELF score Mean (range) 9.1 (7.1 - 11.6) 9.2 (7.1 - 11.6) 8.6 (7.5 - 10.3) Disclosures No relevant conflicts of interest to declare.

Background: Acute intrahepatic cholestasis (AIC) is a rare but severe form of sickle hepatopathy, caused by sickling within hepatic sinusoids, leading to vascular stasis, hypoxic damage and can lead to acute hepatic failure. It is characterised by a combination of clinical, laboratory and radiological features. There is tender hepatomegaly, hyperbilirubinaemia without evidence of extrahepatic biliary obstruction, coagulopathy and thrombocytopenia. Transaminitis, if present is mild or moderate. AIC has a high fatality rate if not treated promptly. Although there is a dearth of evidence on how to treat AIC, the most frequently recommended intervention is by exchange blood transfusion. We report our experience of managing patients with this rare yet serious complication of sickle cell disease at a large tertiary centre over the course of 5 years. Methods: A retrospective review of adult patients who attended the sickle cell service from 1st January 2010 to 30th June 2015 was undertaken. All patients who had had a bilirubin level greater than 300umol/L were identified. Patients with evidence of 'secondary' causes of hyperbilirubinaemia such as biliary sepsis, acute biliary or extrahepatic duct dilatation were excluded. For the remaining patients, clinical notes were reviewed for history of tender right upper quadrant, peak bilirubin levels, coagulation studies, ferritin, ultrasonography or other liver imaging, pre-existing co-morbidities and immediate and long-term clinical outcome were recorded. Results: We identified 16 cases of AIC in 15 patients, out of an excess of 582 patients who attended the Sickle Cell Department over the course of 5 years. In three of these cases, there was also an associated generalised vaso-occlusive crisis. There were 10 male and five female, all of whom had sickle cell anaemia (HbSS), with a median age of 30years (20-48 years). In terms of pre-existing liver disease, one patient had autoimmune hepatitis; another two had chronically deranged liver functions with radiological features suggestive of cirrhosis.Table 1.AgeSexPeak bilirubin; conjugated%INRAPTRThrombocytopeniaConcurrent crisis (VOC)Outcome25F398; 65%1.281.17NoNoAlive25F386; 61%1.221.97NoNoAlive36M299; 69%1.281.33NoYesAlive20M299; 63%1.491.22NoNoAlive37M693; 74%1.371.54NoNoAlive38F671; 100%1.211.41YesNoAlive25F686; 83%1.071.53YesNoAlive25M585; 78%1.251.14NoNoAlive34M450; 88%1.121.58YesNoAlive30M694; 96%2.593.77YesNoDeceased48M719; 66%3.002.33YesNoDeceased22M975; 98%4.0>5NoNoDeceased25F310; N/A1.472.06YesYesAlive25M1043; 99%3.43>5YesNoDeceased44F478; 100%1.331.40NoNoAlive46M644; 91%2.081.2YesNoDeceased The findings on ultrasonography included increased liver reflectivity, hepatomegaly and in two cases, cirrhosis. Choledolithiasis was present in 6 cases, with no evidence of gall bladder infection, inflammation or duct obstruction. Cholecystectomy had been performed in 3 cases; two of these patients had chronically dilated intrahepatic ducts. All patients received transfusions to lower the Haemoglobin S% to less than 30%. Eleven patients received exchange blood transfusions within 72hours of presentation. The remainder, who had received transfusion recently (majority at local hospital) received further transfusions within a week of admission to keep HbS% Seven of the 11 patients who recovered now have normal transaminases with mildly elevated bilirubin levels. Three patients have markedly elevated transaminases and bilirubinaemia, two of whom had previous cholecystectomy and chronically dilated intrahepatic ducts. The third has a heterogenous liver with features of sickle hepatopathy and probable early features of liver fibrosis, while the fourth went on to have a successful liver transplant. There were 5 deaths; all in male patients aged between 22 and 48 years. Two had established cirrhosis; one also had autoimmune hepatitis and CMV viraemia. A third patient had liver biopsy evidence of fibrosis, while a fourth had a CT description of liver with a nodular contour. The fifth patient,was previously fit and well and adenoviraemia was diagnosed. Discussion: Our experience supports the view that AIC can successfully be reversed by timely exchange blood transfusion, and suggests that underlying liver disease and viraemia confer a poor outcome, irrespective of age. Disclosures No relevant conflicts of interest to declare.

Background: In well-resourced countries, early mortality in sickle cell disease (SCD) is no longer a major feature, thus the burden of SCD mortality has shifted to adults. Recent data on patients with SCD in USA confirmed continuing improvement in adult survival, attributed to better preventative care. Health economics may play a key role in clinical outcome in SCD; we hypothesise that survival would be longer in a system which is not insurance based. King's College Hospital, London, UK has a large SCD cohort in a well-resourced setting within a national health service framework. Methods: 712 adult (≥18 years) SCD patients were observed over 10 years (2004-13 inclusive) to identify mortality outcome (total 5268 patient-years of observation with median 8 years of observation per patient, over median 9 total hospital visits). Demographic data, sickle and alpha genotype were documented. Laboratory data were also collected (list in table): outpatient laboratory values were averaged over the 10 year period to create a "steady state" value for each patient. Mean number of hospital admissions with a sickle pain crisis was calculated (total admissions/number of observed years per patient). IBM SPSS Statistics 22 was used for Kaplan Meier survival analysis and then regression analysis was undertaken, based on the Cox proportional hazards model, to identify variables which were associated with mortality, and produce hazard ratios for putative predictors (demographic, laboratory and admission data). Results: 43 patients (6.0%) died during the study at a median age of 42 years (IQR: 31-48). Kaplan Meier analysis showed an estimated median survival of 77 years (95% CI: 68-85) for all sickle genotypes. Sub-analysis by sickle genotype showed: HbSS/HbSβ0 thalassaemia together (33 deaths in 450 patients) with estimated median survival 67 years; and HbSC (8 deaths in 229 patients) with significantly higher estimated median survival 82 years (p Cox regression analysis was conducted for HbSS/HbSβ0 patients (demographic, laboratory and admission data), see table. Risk of death is increased: 2.5-fold if ferritin is high (>1000ug/L), 6% for every extra 10umol/L total bilirubin, 20% for every extra 100 IU/L LDH, 18% for every extra 1 x109/L WBC (all steady state values). Hospitalisation rates were analysed two ways: using the continuous variable, risk of death is increased by 37% for every admission accrued in an individual's mean admission/year statistic; and using a dichotomous variable (high versus low admissions), those with high admission rates have a hazard ratio over 3-fold that of those with low admission rates. Conclusions: These data indicate that adult survival in SCD in our institution is high; estimated median survival of 67 years for HbSS/Sβ0 and 82 years for HbSC. This is markedly longer than those recently quoted from the USA, which may be due to disparities in health economics. Cox regression sub-analysis for the HbSS/Sβ0 group reveals multiple "predictors" of increased mortality risk including classical laboratory markers of SCD severity - iron loading (likely correlated with disease severity via transfusion rate), inflammatory and haemolytic parameters - as well as confirming hospitalisation rate as a simple but strong predictor of survival in SCD. Table. Cox regression analysis for HbSS/HbSβ0 thalassaemia HbSS/HbSβ0 thalassaemia (n=450, 33 deaths) Hazard ratio (CI) p value Demographics Alpha Thalassaemia* 1.342 (0.666-2.706) 0.411 Sex* (M=default) 0.674 (0.339-1.340) 0.261 Laboratory Total bilirubin umol/L 1.006 (1.004-1.008) 1000ug/L* 2.518 (1.212-5.232) 0.013 Lactate dehydrogenase (LDH) IU/L 1.002 (1.000-1.004) 0.038 WBC x109/L 1.181 (1.037-1.345) 0.012 Hb g/L 0.979 (0.956-1.002) 0.073 Reticulocytes x109/L 1.002 (0.999-1.005) 0.285 Admissions Mean number admissions / year 1.374 (1.159-1.630) 0.5/year) 3.131 (1.567-6.259) 0.001 *Dichotomous variables Disclosures No relevant conflicts of interest to declare.

[Graphic][1] Background: Sickle cell disease (SCD) is caused by polymerization of Hemoglobin S, resulting in red blood cell (RBC) sickling, RBC destruction, vaso-occlusive episodes and end-organ damage. No direct anti-polymerization, mechanism-based, preventive therapy is available. GBT440 is a novel small molecule hemoglobin modifier which increases hemoglobin oxygen affinity. In vitro and in vivo studies have shown it to be a potent and direct anti-sickling agent with high specificity for hemoglobin, and that 10-30% hemoglobin modification could be both safe (not compromising oxygen delivery) and effective (preventing HbS polymerization). We hypothesized that a potent antisickling hemoglobin modifier should rapidly interrupt RBC hemolysis, improve anemia and potentially become a safe and effective long-term disease-modifying therapy. We therefore explored safety, pharmacokinetics and pharmacodynamics and potential efficacy in healthy volunteers and SCD patients. Methods: This prospective, randomized, placebo-controlled, double blind, parallel group phase I/II study enrolled healthy volunteers (HV) ages 18-55, and homozygous HbSS SCD patients ages 18-60 with baseline Hb levels ³6 g/dL and ²10 g/dL and without vaso-occlusive crisis or transfusion within 30 days of screening. The study was conducted in two parts: part A tested single ascending doses and part B multiple ascending doses of study drug with 6:2 randomization (GBT440:placebo). Doses administered were: part A, HV cohorts 100mg to 2800 mg, SCD cohort 1000 mg; part B, HV cohorts 300 mg to 900 mg once daily for 15 days, SCD cohort 700 mg once daily for 28 days. The primary endpoint was safety. Secondary endpoints included pharmacokinetics (PK) and pharmacodynamics (PD). Clinical indices of hemolysis were prespecified as endpoints and are described for the SCD multiple dose cohort (700 mg QD for 28 days). Descriptive statistics were used to analyze data. Results: As of July 24 2015, 64 healthy volunteers (HVs) and 16 SCD patients had been enrolled. 54 healthy volunteers had completed the study, 2 were discontinued due to mild-moderate nonserious adverse events (headache, rash) and 8 were in follow-up; 8 SCD patients had completed Part A of the study and 8 were in Part B follow-up. No SCD patients were discontinued; one part B subject had a dose reduction from 700 mg to 400 mg (due to abdominal discomfort). GBT440 was generally well-tolerated, most adverse events were mild, there were no deaths, and there was one serious adverse event (AE) of acute painful crisis in a placebo subject. There were no AEs related to tissue hypoxia. GBT440 showed dose proportional PK, a terminal half-life of 1.5-3 days, high partitioning into RBCs (RBC:Plasma 60-90:1), and a dose dependent increase in hemoglobin oxygen affinity in both HV and SCD patients. In the multiple dose SCD cohort, all patients were evaluable at 28 days (age range 21-52 years; 2 were on hydroxyurea; 3 males/5 females). GBT440-treated patients showed increased hemoglobin, hematocrit and erythrocyte counts with corresponding decreases in LDH, unconjugated bilirubin, reticulocytes and erythropoietin levels with trends evident as early as day 8 compared to no changes in the placebo group (Figure 1 and Table 1). Analysis of peripheral blood smears revealed a marked reduction in sickle cells with GBT440 treatment. Conclusions: Single, oral, daily dosing with GBT440 was well tolerated across a wide dose range and demonstrated dose proportional and predictable PK and PD. GBT440 demonstrated proof of mechanism with a dose-dependent increase in hemoglobin oxygen affinity without causing tissue hypoxia. GBT440 demonstrated proof of concept in SCD patients with rapid reduction in RBC hemolysis and improved oxygen delivery to tissues as evidenced by reduced erythropoietin level, and a marked reduction in circulating sickle cells. These results support further clinical investigation of GBT440 as a potential disease-modifying therapy for SCD. | | Mean change to Day 28 (SEM) | | ----------------------------------------------- | ----------------------------------- | ---------- | | | GBT440 | PLA | | Hemoglogin (g/dL) | 0.8 (0.2) | -0.5 (0.4) | | % Sickle cells in peripheral blood (%) | -83 (9) | 19 (4) | | Erythrocyte count (1012/L) | 0.5 (0.1) | -0.1 (0.2) | | Reticulocyte count (%) | -2.2 (1) | 0.8 (1.6) | | LDH (% change from baseline) | -12 (7) | -9 (1) | | Unconjugated bilirubin (% change from baseline) | -25 (10) | -9.6 (16) | | Erythropoietin (U/L) | -29 (16) | 21 (33) | * GBT = GBT440 treated subject; PLA = placebo subject; SEM = standard error of the mean Table 1. ![Figure 1.][2] Figure 1. Disclosures Lehrer-Graiwer: Global Blood Therapeutics: Employment, Equity Ownership. Howard: Pfizer: Consultancy; Novartis: Consultancy, Other: Travel Grant; Aes-Rx: Consultancy. Layton: Agios: Consultancy; Novartis: Consultancy; Glaxo Smith Kline: Consultancy. Mant: Quintiles: Employment, Equity Ownership. Dufu: Global Blood Therapeutics: Employment, Equity Ownership. Hutchaleelaha: Global Blood Therapeutics: Employment, Equity Ownership. Koller: Global Blood Therapeutics: Employment, Equity Ownership. Oksenberg: Global Blood Therapeutics: Employment, Equity Ownership. Patel: Global Blood Therapeutics: Employment, Equity Ownership. Ramos: Global Blood Therapeutics: Employment, Equity Ownership. [1]: /embed/inline-graphic-2.gif [2]: pending:yes

Recurrent vaso-occlusive crisis (VOC) is a hallmark of sickle cell disease (SCD). Its pathobiology remains poorly understood. VOC occurs on a background of chronic haemolysis with lactate dehydrogenase (LDH), a key biomarker. In steady state, patients have elevated total LDH which becomes more elevated in VOC. Recent data from King's College Hospital (2009-10) shows LDH in VOC was significantly increased by 28% compared to steady state, from 379 +/- 155 IU/L in steady state to 507+/-272 IU/L in VOC. In the same population, platelet counts remained similar in VOC and steady state (363 +/-177x109/L versus 379+/-161x109/L, respectively). Recent analysis has identified LDH as the best bio-predictor of the clinical trajectory of a VOC; severity of VOC appears to correlate with the rise in LDH. A putative mechanism has been suggested after LDH levels were found to be proportional to total activated von Willebrand's Factor (VWF), suggesting that acute SCD may represent a haemolytic microangiopathy on the thrombotic thrombocytopenic purpura (TTP) spectrum. LDH is composed of five isoforms; it has been suggested that some of the increased LDH may be of non-red cell origin, for example bone marrow necrosis. On a retrospective review of our medical records (2006-2013), we identified 12 admissions in 12 different patients with both strikingly elevated LDH (> 1500IU/L) AND thrombocytopenia (platelets The patient characteristics are summarised in table 1. The average age on admission was 29.5 years (+/-10.5 years), 9 patients were male, and included 10 HbSS and 2 HbSC. The clinical phenotypes varied from minimal sickle problems to major co-morbidities. Five patients had frequent hospital admissions (>2/year) due to VOC. All other hospital admissions for these same patients were accompanied by mild elevations in LDH. One patient was on hydroxyurea and two patients were on regular exchange transfusion programmes. Except for patient 3, all the patients had a similar presentation: admission with acute pain, some with a fever, with typical VOC admission bloods i.e. mild Hb decrease, mild LDH increase, and platelets similar to steady state. In the subsequent 2-3 days, patients became more unwell, and hyper-acutely developed both a strikingly elevated LDH, and a synchronous drop in platelet count. Four patients had an associated Hb drop that required blood transfusion. One was red cell exchanged for acute chest syndrome (ACS). Two patients (4, 9) had ADAMTS13 confirmed as low, although not low enough for TTP itself to be diagnosed; they were plasma exchanged. Two patients had bone infarction identified radiologically. The outcome was poor in two of twelve cases: one patient died, and another suffered cauda equina syndrome. For all patients, these episodes represented an extraordinary VOC admission suggesting a separate, unpredictable severe acute phenomenon rather than a typical VOC event. A super elevated LDH together with thrombocytopenia appears to represent a distinct and rare acute sickle phenomenon. Considering it on the TTP spectrum may yield further clues to its underlying pathobiology, although significant bone infarction may also contribute. Interpreting an elevated LDH is not biologically simple, but its clinical utility is undisputed. We suggest using a super elevated LDH concomitant with thrombocytopenia to identify patients potentially at risk of unusually severe VOC, and to consider pre-emptive strategies (e.g. transfusion) early in these cases. Disclosures: No relevant conflicts of interest to declare.

Free circulating DNA has been shown to be present in the plasma of healthy subjects and elevated in conditions characterised by increased cell death, such as cancer and physical trauma. In sickle cell disease (SCD) an increased cell turnover can be expected through hemolysis and recurrent episodes of vaso-occlusion and inflammation, leading to cell death and organ damage. We propose that circulating DNA levels would be higher in patients with SCD, that these elevations would increase with acute crises and that the extent of increase may serve as a prognostic marker of disease severity. Plasma samples were collected from patients with SCD attending the specialist clinic at King’s College Hospital (KCH). Over a 2 year period (April 2003 - May 2005) a total of 442 samples from 154 patients (105 HbSS, 46 HbSC, 3 HbS/β0 thalassemia) in steady state at each visit to the KCH outpatient sickle clinic was collected. Samples were also obtained from 21 of these 154 patients during an acute crisis, as defined by hospital admission for sickle-related pain. Control subjects consisted of 55 healthy Afro-Caribbean and West African individuals (53 HbAA, 2 HbAS). Plasma DNA concentration was measured by real-time quantitative PCR using a probe specific for the β-globin gene. As the distribution of plasma DNA levels was not gaussian, data was normalised by log-transformation. The median plasma DNA levels in genome equivalents (GE)/ml were as follows: 933 (range 144 to 19370) in controls; 841 (range 60.1 to 16070) in all sickle patients (SS, HbSC and S/β0 thalassemia) during steady state; 970 (range 92 to 16070) in SS and S/β0 thalassemia during steady state; 719 (range 60.1 to 14650) in SC during steady state. Median DNA levels for crisis samples were 10070 (range 444 to 57910) in all SCD and 12000 (range 444–57910) in the SS and S/β0 thalassemia group. There was no significant difference in plasma DNA levels between controls and SCD patients during steady state. Differences between steady state and crisis did not reach significance in the SC group due to the small number of crisis samples (n=3). However, mean plasma DNA levels for sickle patients during steady state, and those in crisis were highly significantly different (by Student’s t test) for all sickle patients (p

Chronic hyperbilirubinemia is common in patients with sickle cell disease (SCD), frequently resulting in the formation of gallstones. This hyperbilirubinemia (predominantly unconjugated) is attributed to hemolysis that exceeds the conjugating capacity of the hepatic UDP-glucuronosyltransferase (UGT1A) enzyme. Previous studies have shown that genetic variants ([TA]n repeats) in the promoter region of the UGT1A gene have a major influence on the levels of bilirubin and gallstones. Alpha-thalassemia, which is associated with reduced hemolysis, has also been shown to affect bilirubin levels. Another potential modulating factor is heme-oxygenase, a rate-limiting enzyme in the heme catabolic pathway that results in the production of bilirubin. While the severity of jaundice and cholelithiasis in patients with SCD is predisposed by the inheritance of certain variants of the UGT1A gene, inconsistencies have been observed. We propose that some of these inconsistencies may be explained by the modulating effects of genetic variants of HO1 and α-thalassemia. A total of 263 patients with SCD attending specialist clinics in two hospitals were studied: King’s 116 SS, 5 Sβ0 and 59 SC; St Thomas’ 83 SS. 81 ethnically matched subjects were recruited as controls (HbAA). Groups were age and sex matched. Cholelithiasis data, ascertained by liver ultrasound, was available for a subset of SCD patients (76 SS, 4 SC). Samples were genotyped for variants of UGT1A, HO1 and α-thalassemia. The different genetic allele distributions were statistically similar between groups. Data was analysed according to the sum of [TA] repeats on both alleles of UGT1A. A range of 10–15 [TA] repeats was observed. For HO1, the median sum of repeats on both alleles was 63, so samples were grouped as

Adults with sickle cell disease (SCD) may develop sickle chronic lung disease which appears to be a complication of chronic hemolysis and repeated episodes of pulmonary vaso-occlusion. Pulmonary function tests have usually been used to document the severity of lung disease in SCD, but some patients cannot successfully undertake such examinations. Recently, high resolution computed tomography (HRCT) has been shown to be of value in the evaluation of patients with diffuse lung diseases. Assessment of lung disease in SCD by HRCT, however, has not been fully explored. The study sets out to investigate the relationship of any pulmonary function abnormalities in adults with SCD to a non-invasive measure of hemolysis and findings on HRCT. The study population consisted of 33 Hb SS subjects (12 males) with a median age of 36 (range 17–67) years, median height of 167 (range 53–188) cm, and median weight of 69 (range 52–92) kg. Pulmonary function was assessed by measurements of lung volumes, spirometry, gas transfer and oxygen saturation, and hemolysis by measurement of end-tidal carbon monoxide (ETCO). The degree of a lobar volume loss and ground glass opacification and prominence of central vessels on HRCT were quantitatively assessed. There was a wide variation in the lung function of the cohort. Nine patients had a restrictive lung function abnormality, five an obstructive abnormality and four a mixed restrictive/obstructive abnormality. Twenty-seven of the patients completed assessment of ETCO levels. ETCO levels correlated positively with bilirubin levels (rs=0.66, p=0.0002) and the absolute reticulocyte count (rs=0.70, p=0.0002), and negatively with hemoglobin (rs=−0.51, p=0.008). ETCO levels negatively correlated with FEV1 (p=0.006), VCpleth (p=0.006), sGaw (p=0.04) and SpO2 (p=0.007). A reticular pattern, lobar volume loss and prominent central vessels were the three most common abnormalities on HRCT. FEV1 (p Our results suggest that non-invasive assessment of hemolysis and/or HRCT examination might facilitate identification of SCD patients with respiratory function impairment. More of the patients had abnormalities on HRCT than on lung function testing, which suggests that HRCT is a more sensitive detector of respiratory abnormalities than lung function testing. This hypothesis merits testing by serially assessing SCD patients to determine if those with only HRCT abnormalities subsequently develop lung function abnormalities.