Sickle-related Events Research Articles

Hydroxyurea for Children and Adults with Hemoglobin SC Disease.

Hemoglobin SC (HbSC) is a common sickle hemoglobinopathy that causes acute complications, chronic organ damage, and early death with no established disease-modifying treatment. In this trial, we examined the safety and efficacy of hydroxyurea treatment in patients with HbSC. Prospective Identification of Variables as Outcomes for Treatment (PIVOT) was a double-blind, randomized, placebo-controlled, non-inferiority phase 2 trial in which we assigned children and adults with HbSC in Ghana to 12 months of hydroxyurea or placebo. The primary end point was hematologic dose-limiting toxicities (DLTs), including cytopenias or elevated hemoglobin levels during 12 months of blinded treatment. Clinical end points included vaso-occlusive pain events, acute chest syndrome, hospitalizations, transfusions, and malaria. Quality-of-life measures, organ function assessments, and rheological measurements were also collected. Of the 243 enrolled patients (118 female), 212 eligible participants initiated blinded treatment at 20.0±5.0 mg/kg/day. DLTs occurred in more participants on hydroxyurea (33%) than the placebo (11%), with a difference of 22 percentage points (95% confidence interval [CI],11 to 34 percentage points), which exceeded the predefined 15 percentage point noninferiority margin. Elevated levels of hemoglobin occurred in 12 participants on hydroxyurea and 10 on the placebo. Hydroxyurea treatment was associated with 57.0 versus 149.6 vaso-occlusive pain events per 100 person-years (incidence rate ratio [IRR] 0.38; 95% CI, 0.28 to 0.52), and 12.9 versus 30.6 hospitalizations per 100 person-years (IRR 0.42; 95% CI, 0.22 to 0.81). A composite of acute sickle-related events occurred in 37 participants on hydroxyurea versus 69 participants on placebo (IRR 0.39; (95% CI, 0.26 to 0.59), a difference observed in both children and adults. The PIVOT trial did not meet its primary end point. Hydroxyurea at 20 mg/kg in patients with HbSC was associated with more hematologic DLTs than placebo, but most were mild and transient. Hydroxyurea was associated with less vaso-occlusive pain and fewer sickle-related events in both children and adults; a new trial will need to be done to establish the efficacy of this approach. (Funded by Theravia; Pan-African Clinical Trials Registry number, PACTR 202108893981080).

Increased Hydroxyurea Prescribing Practices over Ten Years with Improved Clinical Outcomes in Children with Sickle Cell Anemia: A Single Center's Experience

Introduction: Sickle cell anemia (SCA) is a severe and life-threatening disorder that requires treatment to prevent short- and long-term complications and prolong life. The primary disease-modifying therapy for SCA remains hydroxyurea (HU). Due to 30 years of evidence demonstrating safety and efficacy culminating with BABY HUG, the 2014 National Heart, Lung, and Blood Institute (NHLBI) guidelines recommended offering HU to all children with the severe sickle cell genotypes (HbSS, HbS-0thalassemia) beginning at 9 months of age. Despite these recommendations, HU utilization in pediatric patients in the US remains with rates reported as low as 38-47% among the most severe genotypes as recently as 2017. Providers have identified a number of barriers to more widespread use, including the inability to identify which patients may benefit, concern for possible side effects, uncertainties regarding dose, and concerns regarding possible nonadherence. As complications begin as early as the first year of life, it is a disservice to withhold a proven therapy. Here, we describe the effective and nearly universal uptake of HU in our pediatric SCA population at Cincinnati Children's Hospital Medical Center (CCHMC). Methods: We performed an IRB-approved retrospective review to assess the hydroxyurea prescribing practices and clinical complications of patients with SCA treated at CCHMC from 2010-2019. Following the NHLBI guidelines' release in 2014, we changed the recommended age of HU initiation to be within the first year of life. Corresponding with this change, we have initiated HU for most young children with an individualized, pharmacokinetics (PK)-guided dosing strategy through both the Therapeutic Response Evaluation and Adherence Trial (TREAT, NCT03789591) and the Hydroxyurea Optimization through Precision Study (HOPS, NCT03789591). Due to the onset of symptoms for some patients before 9 months, we have offered HU initiation as early as 6 months of age since 2015. Our objective was to compare the rates of HU utilization, age of initiation, and hospitalization rate before (2010-13) and after (2014-19) the release of the NHLBI guidelines and the start of the TREAT study in 2014. Demographic and clinical data, including sickle cell genotype, prior/alternative therapy, SCA-related complications, HU dosing, and laboratory values were abstracted from each patient's electronic medical record (EMR). Patients were identified using the EMR's sickle cell registry. Results: We identified 439 patients with sickle cell disease followed at CCHMC from 2010-2019 (47% female, age range: 0-22 years); 275 had SCA (HbSS, HbS-0-thalassemia, or HbSD). The proportion of patients with SCA prescribed HU increased from 2010-19, from 35% in 2010 to 80% in 2019 with significantly more patients initiating HU during 2014-19 versus 2010-13 (average 20 versus 12 patients/yr, p = 0.0028, Figure 1A). The age of HU initiation was significantly lower during 2014-19 compared to 2010-13 (median = 2 y vs 6 y, p = 0.00028). Of 35 patients with SCA not on HU in 2019, 28 received chronic transfusions and the remaining 7 received no disease-modifying therapy with 3/7 patients not yet at the age to start HU. Ninety-six percent (53/55) of children with SCA born during 2014-19 were on treatment, including 52 on HU (median starting age = 10 months) and 1 on chronic transfusions; 45/52 (87%) were enrolled on TREAT or HOPS. With increased HU utilization during this study period, the number of admissions for sickle-related events was significantly lower in the 2014-19 group versus 2010-13 (2.8 vs 6.9 admissions/pt, p = 9.0 x 10-10) with no change in non-SCA related admissions, most commonly for fever (3.8 vs 4.0 admissions/pt, p = 0.8, Figure 1B). Conclusions: HU has become the standard of care for children with SCA, beginning at 6-9 months of age, prior to the onset of acute and chronic complications. Despite widespread concerns that HU will not be accepted by patients and national trends demonstrating low rates of utilization, we have shown that a deliberate, systematic, and preventive approach to HU is possible and results in nearly universal acceptance of HU for young patients with SCA. This has translated to excellent laboratory responses and significantly fewer SCA-related clinical complications in our population. Our approach and improved patient outcomes can serve as a model for other programs to expand their HU treatment for more children with SCA. Figure 1 Disclosures Kalfa: Agios Pharmaceuticals, Inc: Consultancy, Research Funding; Forma Therapeutics, Inc: Research Funding. Malik:Aruvant Sciences, CSL Behring: Patents & Royalties; Aruvant Sciences, Forma Therapeutics, Inc.: Consultancy.

Clinical Outcomes For Patients With Sickle Cell Disease: 24-Month Follow-Up In An Ongoing 3-Year, Prospective, Non-Interventional Registry Trial

▪ IntroductionPatients (pts) with sickle cell disease (SCD) experience a heterogeneous clinical course, with a range of symptoms and sequelae. We describe clinical outcomes and treatment patterns from a prospective registry of pediatric and adult pts with SCD. MethodsPts ≥2 years old with HbSS, HbSC, or HbS/β-thalassemia were enrolled from 57 US centers and assessed every 6 months (mos) for up to 3 years. Differences between pediatric and adult pts at 24 mos follow-up are reported. (ClinicalTrials.gov NCT01220115). ResultsA total of 498 pts completed the baseline visit (74.1% HbSS disease, 15.3% HbSC, and 10.4% HbS/β-thalassemia) (Table 1). At baseline, the following conditions were more frequent in adults: avascular necrosis, gallbladder disease, leg ulcers, and pulmonary hypertension. Pediatric pts had more frequent asthma/reactive airway disease, dactylitis, and splenic sequestration. The nature of sickle-related events varied between adult and pediatric pts (Table 2). Prior to study, adults had higher frequencies of pain crises, strokes, and priapism, while pediatric pts had more frequent infections and acute chest syndrome (ACS)/pneumonia. On study, a similar proportion of pediatric and adult pts (56.4% overall) were hospitalized, most frequently due to pain, fever, and ACS/pneumonia; a greater proportion of pediatric pts were hospitalized due to fever (P<0.05). The percentage of pts who received a transfusion and/or chelation while on study was similar between adult and pediatric pts. Almost half of the pediatric and adult groups received hydroxyurea prior to and during the study. High rates of absenteeism were observed, with 51% of pediatric pts and 44.4% of adults missing 1 to 10 days of school or work in the year before study. ConclusionsDespite advances in care, SCD is associated with significant morbidity that contributes to high rates of hospitalization and absenteeism in both pediatric and adult pts. Continued follow-up in this registry will provide additional information about disease patterns and pt management. Disclosures:Heeney:Novartis: Consultancy, Research Funding; Eli Lilly: Research Funding. Off Label Use: Hydroxurea is indicated to reduce the frequency of painful crises and to reduce the need for blood transfusions in adult patients with sickle cell anemia. It is not approved for use in children. Mueller:Novartis: Research Funding. Adams-Graves:Novartis: Consultancy, Speakers Bureau. Paley:Novartis: Employment. Esposito:Novartis: Employment. Katie:Novartis: Employment. Vichinsky:Novartis: Consultancy, Research Funding; ApoPharma: Consultancy, Research Funding; ARUP: Research Funding, Research Laboratory, Research Laboratory Other.

IHP-Loaded Red Blood Cells Efficacy in Sickle Transgenic Mice

Abstract 2119Homozygous patients (SS) display the most severe form of sickle cell disease (SCD) with high risk of painful complications during their lifetime including vaso-occlusions (VOC), acute chest syndromes (ACS) and strokes. Even though multiple factors seem to be involved in those sickle related events, hypoxia is the most important triggering factor. Transfusing patients with IHP-RBCs (homologous RBCs loaded with Inositol Hexaphosphate) could potentiate existing transfusion therapy. Indeed, IHP by reducing the oxygen-hemoglobin affinity improves the capacity of transfused RBCs to release more oxygen in the blood stream and to the tissues. In a previous work, we showed that IHP-RBCs were 7-fold more effective than normal RBCs to reduce in vitro sickling of homozygous patient RBCs (Bourgeaux et al, Transfusion, 2010). We hypothesized that in vivo, IHP-RBCs with increased oxygenation properties may reduce the severity of SCD pathophysiology in transgenic mice.In a first study, BERK transgenic mice which are more representative of SCD in childhood (splenomegaly and RBC sequestration crisis) were used to evaluate the effect of chronic IHP-RBCs transfusions. Mice (n=5-7/group) were subjected to 4 repeated RBC exchanges (every 2 weeks) using IHP-RBCs or control RBCs. One week after the last exchange, mice were challenged with hypoxia and sacrificed for organ and hematological analysis. It was observed an improved survival rate and a prevention of anemia under hypoxic conditions (Hb=7.0±0.6 g/dl vs 5.9±0.4 g/dl for mice receiving control RBCs). On the contrary to control RBCs, IHP-RBCs treatment also corrected impaired brain development observed in female BERK mice with higher brain weight to total body weight ratio (2.12±0.07% versus 1.89±0.08% for untreated mice, p<0.05). IHP-RBCs by modulating cellular blood components and improving the vascular tone also lowered the risk of VOC in BERK mice with decreased proportion of reticulocytes (26±6 % vs 34±4% for treatment with normal RBCs and 42±2 % for untreated mice), reduced levels of soluble thrombospondin-1 involved in adhesion processes (104±22 pg/mL vs 314±56 pg/mL for treatment with normal RBCs and 223±50 pg/mL for untreated mice) as well as endothelin-1, a peptide promoting vaso-constriction.In a second study, SAD transgenic mice which were shown to be a pertinent model for acute sickle events were used to investigate the efficiency of a simple transfusion of IHP-RBCs. Mice (n=10–12/group) partially exchanged with IHP-RBCs or control RBCs were subjected to an acute hypoxic-reoxygenation stress 24h post-transfusion in order to induce specific lung damages. The therapeutic benefice of IHP-RBCs over classical transfusion to reduce lung injury was evidenced by significantly decreased mRNA levels of molecules involved in intravascular pathology (7-fold and 8-fold reduction in VCAM-1 and Tissue factor mRNA levels as compared to mice receiving control RBCs (p<0.05). AOPP used as specific biomarker of oxidative stress was significantly reduced with IHP-RBCs treatment as compared to untreated mice (2.64±0.27 μmol/L vs 3.87±0.30 μmol/L respectively).From a safety point of view, one single intravenous administration of IHP-RBCs showed no apparent toxicity in healthy mice and seems to be as safe as classical transfusion. Only moderate hemolysis was observed after transfusion with increased serum bilirubin level but this parameter recovered normal values within 24h.In conclusion, entrapping IHP into transfused RBCs is a powerful tool to prevent acute or chronic manifestations of SCD in transgenic mice. For therapeutic use in human, IHP-RBCs may potentiate chronic transfusions by reducing the number of RBC units to be transfused but also the frequency of transfusions thus improving patient quality of life. In addition, with the recent improvements in scoring acute manifestations of SCD, IHP-RBCs may also potentiate classical transfusion in the treatment of chest syndromes by acting more rapidly and more efficiently. Disclosures:Bourgeaux:ERYtech Pharma: Employment. Campion:ERYTECH Pharma: Employment. Chevrier:ERYtech Pharma: Employment. Godfrin:ERYTECH Pharma: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

The impact of a regular erythrocytapheresis programme on the acute and chronic complications of sickle cell disease in adults

Thirteen adult patients aged 22-63 (median 30) years with sickle cell disease (SCD) were enrolled in a regular erythrocytapheresis (ECP) programme at a single institution between December 1998 and November 2008. The indications for enrolment were recurrent painful crises (PC), acute chest syndrome (ACS), silent cortical ischaemia, pulmonary hypertension, multi-organ crises and pregnancy. Endpoints retrospectively evaluated included the incidence of SCD-related acute events requiring hospitalization following and prior to regular ECP, the development of new and progression of pre-existing related end-organ damage, the effectiveness in reducing HbS levels acutely and prior to the next exchange and the transfusion-related complications. Sixteen acute sickle-related events occurred in five patients in 846 months of patient follow-up. In all patients with reliable data available pre-ECP, the frequency of such events was reduced following commencing regular ECP. No patient experienced stroke, multi-organ crises or developed new and/or progression of end-organ dysfunction. Regular ECP reduced HbS levels to the target of <30% immediately post-exchange. Alloimmunization rates were comparable to the literature and ECP was effective in preventing progressive iron overload. Regular ECP was demonstrated to be an effective, well-tolerated therapy for both acute and chronic complications of SCD in adults.

Matched‐related donor transplantation for sickle cell disease: report from the Center for International Blood and Transplant Research

We report outcomes after myeloablative haematopoietic cell transplantation (HCT) from human leucocyte antigen (HLA)-matched sibling donors in 67 patients with sickle cell disease transplanted between 1989 and 2002. The most common indications for transplantation were stroke and recurrent vaso-occlusive crisis in 38% and 37% of patients respectively. The median age at transplantation was 10 years and 67% of patients had received >10 red blood cell transfusions before HCT. Twenty-seven percent of patients had a poor performance score at transplantation. Ninety-four percent received busulfan and cyclophosphamide-containing conditioning regimens and bone marrow was the predominant source of donor cells. Most patients achieved haematopoietic recovery and no deaths occurred during the early post-transplant period. Rates of acute and chronic graft-versus-host disease were 10% and 22% respectively. Sixty-four of 67 patients are alive with 5-year probabilities of disease-free and overall survival of 85% and 97% respectively. Nine patients had graft failure with recovery of sickle erythropoiesis, eight of who had recurrent sickle-related events. This report confirms and extends earlier reports that HCT from HLA-matched related donors offers a very high survival rate, with few transplant-related complications and the elimination of sickle-related complications in the majority of patients who undergo this therapy.

Outcome of pregnancy in homozygous sickle cell disease.

Previous reports on pregnancy in homozygous sickle cell (SS) disease are biased by hospital-based, more severely affected subjects and may have underestimated recurrent early pregnancy losses. We report pregnancy outcome in a representative sample of SS subjects subsequently referred to as "subjects" or "sickle cell subjects," and matched normal controls followed from birth. The outcomes of 94 pregnancies in 52 subjects and 157 pregnancies in 68 controls followed in a cohort study from birth are presented. Outcome measures included the age at menarche, interval to first pregnancy, outcome of pregnancy, and maternal complications. Possible predictors of low birth weight are assessed. Outcomes were compared by the Kaplan-Meier analysis for interval to first pregnancy and by Student t test, chi(2) test, or Fisher exact test, as appropriate. Correction was made for multiple testing, and multiple linear regression was used for analysis of birth weight. Compared with controls, SS subjects had later menarche (median age 15.4 versus 13.0 years) and first pregnancy (median age 23.7 versus 20.1 years), and more spontaneous abortions (36% versus 10%). Babies of SS subjects had a lower gestational age (P <.001) and lower birth weight (P <.001), the latter being significantly affected by sickle-related events in pregnancy. There was no difference in pregnancy-induced hypertension, preeclampsia, or antepartum or postpartum hemorrhage, but a retained placenta was marginally more common in SS subjects (Fisher exact test, P =.007 after adjustment for multiple testing). Two SS subjects died, a mortality rate of 2.1%. The increased fetal loss and maternal morbidity in mothers with homozygous sickle cell disease is confirmed. II-2

Sickle cell disease and pregnancy

Sickle cell disease refers to a group of genetic disorders characterised by the predominance of hemoglobin S. This includes sickle cell anemia (SS) sickle hemoglobin C disease (SC), sickle beta thalassemia plus (Sβ +Thal), sickle beta thalassemia zero (β 0Thal), sickle with alpha thalassemia (SSαThal) and rare combinations of sickle hemoglobin with Hb D, Hb O, etc. While pregnancy does carry risk for the woman with sickle cell disease (SCD) and for the fetus, pregnancy can be well tolerated by the major genotypes. Infants born from these pregnancies may tend to be small for gestational age and undergo premature delivery. While complications for both sickle-related events and for pregnancy are seen, data to date state that women are able to complete their pregnancies successfully. Counselling, regular prenatal visits and aggressive treatment of acute events are always indicated. There is no proof that prophylactic transfusion alters the outcome of pregnancy. Transfusion therapy should be reserved for those patients with previous perinatal mortality, pre-eclampsia, acute chest syndrome, new onset neurological event, severe anemia and in preparation for surgical intervention. Thus, blood transfusion will continue to have a role in management of obstetrical and medical indications accompanied by meticulous prenatal care and early detection of complications. In addition, newborn screening should be recommended for the early detection of infants with disease.