High-risk Sickle Cell Disease Research Articles

Neurocognitive outcome in children with sickle cell disease after myeloimmunoablative conditioning and haploidentical hematopoietic stem cell transplantation: a non-randomized clinical trial.

Due to the risk of cerebral vascular injury, children and adolescents with high-risk sickle cell disease (SCD) experience neurocognitive decline over time. Haploidentical stem cell transplantation (HISCT) from human leukocyte antigen-matched sibling donors may slow or stop progression of neurocognitive changes. The study is to determine if HISCT can ameliorate SCD-associated neurocognitive changes and prevent neurocognitive progression, determine which specific areas of neurocognitive functioning are particularly vulnerable to SCD, and determine if there are age-related differences in neurocognitive functioning over time. We performed neurocognitive and neuroimaging in SCD recipients following HISCT. Children and adolescents with high-risk SCD who received parental HISCT utilizing CD34+ enrichment and mononuclear cell (T-cell) addback following myeloimmunoablative conditioning received cognitive evaluations and neuroimaging at three time points: pre-transplant, 1 and 2 years post-transplant. Nineteen participants (13.1 ± 1.2 years [3.3-20.0]) received HISCT. At 2 years post-transplant, neuroimaging and cognitive function were stable. Regarding age-related differences pre-transplantation, older children (≥13 years) had already experienced significant decreases in language functioning (p < 0.023), verbal intelligence quotient (p < 0.05), non-verbal intelligence quotient (p < 0.006), and processing speed (p < 0.05), but normalized post-HISCT in all categories. Thus, HISCT has the potential to ameliorate SCD-associated neurocognitive changes and prevent neurocognitive progression. Further studies are required to determine if neurocognitive performance remains stable beyond 2 years post-HISCT.Clinical trial registration: The study was conducted under an investigator IND (14359) (MSC) and registered at clinicaltrials.gov (NCT01461837).

Longitudinal Predictors of Pain in Pediatric Sickle Cell Disease.

Despite the identified pathophysiology of vaso-occlusive pain in sickle cell disease (SCD), predictors of pain in youth with SCD remain elusive. In this study, we measured changes in pain frequency, intensity, and interference over 1 year and examined biopsychosocial risk factors (SCD disease severity, age, female, depression, and sleep quality) as possible longitudinal predictors. Medical history was obtained from retrospective chart review for 79 children with SCD (ages 2-18 years; 48.1% female; 100% Black/African American; 83.5% SCD, SS genotype). As part of a clinical screening protocol, caregivers (n = 79) and youth 8-18 years (n = 43) completed psychosocial questionnaires approximately 1 year apart (M = 15.52 months, SD = 5.69). Zero-order correlations, paired t-tests, and hierarchical linear models examined longitudinal predictors of pain. The longitudinal bidirectional relationship between pain and sleep was also examined. The rate of severe SCD disease increased from 41.8% to 55.7% across the year, while most hematologic medical parameters remained stable. Increased depression and pain interference at survey 1 significantly predicted increased pain interference at survey 2. Poor sleep quality and increased pain frequency at survey 1 predicted increased pain frequency at survey 2. Finally, increased pain interference at survey 1 predicted poor sleep quality at survey 2. History of pain, depression, and sleep quality were longitudinal predictors of pain over 1 year in youth with SCD. Identifying longitudinal predictors of pain may lead to earlier identification of patients with a high-risk SCD pain phenotype and earlier medical, psychological, and behavioral interventions.

394 - Determining the Safety and Efficacy of Prophylactic Defibrotide Administration in Children, Adolescents, and Young Adults with High-Risk Sickle Cell Disease (SCD) or Beta Thalassemia Major Following Myeloimmunoablative Conditioning (MAC) and Haploidentical Stem Cell Transplantation Utilizing CD34+ Selection and T-Cell (CD3) Addback (IND127812)

394 - Determining the Safety and Efficacy of Prophylactic Defibrotide Administration in Children, Adolescents, and Young Adults with High-Risk Sickle Cell Disease (SCD) or Beta Thalassemia Major Following Myeloimmunoablative Conditioning (MAC) and Haploidentical Stem Cell Transplantation Utilizing CD34+ Selection and T-Cell (CD3) Addback (IND127812)

Haploidentical stem cell transplantation for patients with sickle cell disease: current status

For patients with high-risk sickle cell disease (SCD) without any available matched sibling or unrelated donor, haploidentical stem cell transplantation (haploHCT) expands the availability of this life-saving intervention to nearly all patients who may benefit from HCT. The greatest challenge in haploHCT has been the significant risk of graft failure. Developing a treatment modality which sustains engraftment without increasing the incidence of debilitating graft-versus-host disease (GvHD) remains the ultimate goal. A number of modifications have been explored to overcome the high incidence of graft rejection and severe GvHD including: (1) ex-vivo T-cell depletion (via CD34+ selection, CD3+/CD19+, or TCRαβ+/CD19+ depletion), and (2) in vivo T-cell depletion using unmanipulated grafts followed by post-transplant cyclophosphamide (PTCy) for GvHD prophylaxis. Furthermore, the presence of donor-specific anti-HLA antibodies (DSA) has been associated with an increased risk of both graft failure and poor graft function. Several approaches for desensitization ameliorate this risk when a suitable donor without DSA is not available. In addition to advances in supportive care, the recent demonstration that stable mixed chimerism post-HCT sufficiently sustains symptom-free status has opened the door for less toxic treatment approaches yielding excellent survival outcomes. Though late effects remain uncertain, the goal of finding the least toxic conditioning regimen while providing the highest rate of donor engraftment draws closer within reach. In this review, the authors aim to present the latest findings, challenges, and treatment modalities of this life-saving modality.

438 - Determining the Safety and Efficacy of Prophylactic Defibrotide Administration in Children, Adolescents, and Young Adults with High-Risk Sickle Cell Disease (SCD) or Beta Thalassemia Major Following Myeloimmunoablative Conditioning (MAC) and Haploidentical Stem Cell Transplantation Utilizing CD34+ Selection and T-Cell (CD3) Addback (IND127812)

438 - Determining the Safety and Efficacy of Prophylactic Defibrotide Administration in Children, Adolescents, and Young Adults with High-Risk Sickle Cell Disease (SCD) or Beta Thalassemia Major Following Myeloimmunoablative Conditioning (MAC) and Haploidentical Stem Cell Transplantation Utilizing CD34+ Selection and T-Cell (CD3) Addback (IND127812)

320 - Safety and Efficacy of High Dose Granulocyte Colony Stimulating Factor Mobilization in Familial Haploidentical Adult Donors with Sickle Cell Trait Followed By CD34+ Cell Enrichment and Mononuclear Cell Add-Back Prior to Haploidentical Allogeneic Transplantation in High-Risk Sickle Cell Disease Recipients

320 - Safety and Efficacy of High Dose Granulocyte Colony Stimulating Factor Mobilization in Familial Haploidentical Adult Donors with Sickle Cell Trait Followed By CD34+ Cell Enrichment and Mononuclear Cell Add-Back Prior to Haploidentical Allogeneic Transplantation in High-Risk Sickle Cell Disease Recipients

The ektacytometric elongation Index (EI) of erythrocytes, validation of a prognostic, rheological biomarker for patients with sickle cell disease.

Validation of the measurement of erythrocyte deformability as a useful prognostic, rheological biomarker for patients with sickle cell disease (SCD). The degree of reduced deformability was based on the value of the maximum elongation index (EImax ) of the deformability curve of an osmotic gradient ektacytometer. The performance of this technique was analytically and clinically validated by analysing 200normal subjects and 100patients with well-documented thalassemia's and Hb variants in relation to their clinical condition. In this study, we show that EImax is a reproducible parameter with a small inter-individual coefficient of (Biological) variation (CV)=1.6% and a small intra-individual CV=3.5%. We demonstrate that loss of deformability correlates with the clinical condition and the various mutations underlying sickle cell disease and thalassemia. For SCD patients, a strongly reduced EImax with a cut-off =0.360 is a signal for future vaso-occlusive (VOC) events requiring hospitalisation with a specificity=85%, sensitivity=80%, PPV=81% and NPV=84% based on a ROC curve (AUC=0.89). This study validated the clinical utility of EImax as a prognostic marker for future clinical problems in individual high-risk SCD patients. In addition, EImax may help to achieve an adequate personal transfusion policy for an optimal blood flow in anaemic patients with SCD.

Neurodevelopmental Outcomes in Preterm Children with Sickle Cell Disease.

To explore the combined effect of pediatric sickle cell disease (SCD) and preterm birth on cognitive functioning. Cognitive functioning was examined in children ages 6-8 with high risk SCD genotypes born preterm (n = 20) and full-term (n = 59) and lower risk SCD genotypes/no SCD born preterm (n = 11) and full-term (n = 99) using tests previously shown to be sensitive to SCD-related neurocognitive deficits. Factorial ANOVAs and log linear analyses were conducted to examine the relationship between SCD risk, preterm birth status, and cognitive outcomes. Continuous scores were examined for specific tests. Children were categorized as having an abnormal screening outcome if at least one cognitive score was ≥1.5 standard deviations below the population mean. Children with elevated risk due to high risk SCD and preterm birth performed worse than other groups on a test of expressive language but not on tests that emphasize processing speed and working memory. There was a three-way interaction between preterm status, SCD risk, and abnormal screening outcome, which was largely driven by the increased likelihood of abnormal cognitive scores for children with high risk SCD born preterm. The combination of SCD and preterm birth may confer increased risk for language deficits and elevated rates of abnormal cognitive screenings. This suggests that neurodevelopmental risk imparted by comorbid SCD and preterm birth may manifest as heterogenous, rather than specific, patterns of cognitive deficits. Future studies are needed to clarify the domains of cognitive functioning most susceptible to disease-related effects of comorbid SCD and preterm birth.

Promising Results at 1 Year Follow-up Following Familial Haploidentical (FHI) T-Cell Depleted (TCD) with CD34 Enrichment and T-Cell (CD3) Addback Allogeneic Stem Cell Transplantation in Patients with High-Risk Sickle Cell Disease (SCD) (IND 14359)

AlloSCT from HLA-matched MSD has been successful for high-risk SCD, and is the only known curative therapy (Talano/Cairo et al EJH, 2014). We have recently demonstrated 100% EFS and absence of sickle cell symptoms following reduced toxicity conditioning in HLA matched sibling donor (MSD) or cord blood AlloSCT (Bhatia/Cairo et al BMT, 2014). However, 5 out of 6 children lack an HLA MSD without SCD. Only 19% of recipients of African descent will identify a well-matched unrelated donor (MUD) and results after unrelated UCBT are poor (Radhakrishnan/Cairo et al BBMT, 2013). Recent results utilizing matched unrelated donors in a multi-center trial showed unacceptable rates of cGVHD at 62% (95% CI 41-77) (Shenoy et al Blood, 2016). We demonstrated CD34+ selection followed by T-cell addback from MUD in pediatric recipients led to 100% engraftment with minimal aGVHD (Geyer/Cairo et al BJH, 2011). Limitations in the past of various T-cell depletion methods have included a higher incidence of graft failure, delayed immune reconstitution, opportunistic fungal infection and higher incidence of cGVHD. FHI TCD AlloSCT utilizing the approach of CD34+ enrichment and T-cell addback could expand the donor pool and improve outcomes for patients with high risk SCD and have similar outcomes to AlloSCT from HLA MSD.This SCD consortium trial (www.sicklecelltransplantconsortium.org) (NCT01461837) is investigating the safety, feasibility, EFS, donor chimerism, graft failure, aGVHD and cGVHD after FHI TCD AlloSCT in high-risk SCD patients.High risk included: ≥1 CVA, ≥2 ACS, ≥3 VOC in past 2 years, or 2 abnormal TCDs. Patients (2-<21 yrs) who have ≥1 high-risk SCD features were eligible. Patients received hydroxyurea and azathioprine, day -59 - day -11, fludarabine (150mg/m2), busulfan (12.8mg/kg) (targeted trough Css of 600-900), thiotepa (10 mg/kg), cyclophosphamide (200mg/kg), R-ATG (8mg/kg), and TLI (500cGy) followed by FHI T-cell depleted AlloSCT. AGVHD prophylaxis: tacrolimus. We utilized the CliniMACS to enrich for peripheral blood HPC's; target dose of 10 x 106 CD34+ cells/kg with a fixed dose of 2 x 105 CD3+ T cells/kg. The Child Health Rating Inventories (CHRIs) was used to serially collect parent proxy-rated health-related quality of life (HRQL).Twenty-one patients have been enrolled. Nineteen patients have received AlloSCT to date. Fifteen patients utilized maternal donors and 4 patients utilized paternal donors. Two donors encountered thrombocytopenia that resolved spontaneously. The mean ± SD CD34+ enrichment prior to cryopreservation was 12.66 ± 3.3 x 106/kg and log T-cell depletion was 4.8 ± 0.58. Evaluable pts had early neutrophil engraftment (median day +9), and ≥95% whole blood and RBC (CD71) donor chimerism at 1yr. Probability of aGVHD n=17, 7.1% (CI95: 0-70.0); cGVHD n=17, 20% (CI95: 0.7-59.6) (Figure 1A and 1B). Probability of 1-Year Overall Survival (OS) n=17; 88.2% (CI95: 60.6-96.9) (Figure 1C). Immune reconstitution was robust with 1 yr NK, CD3, CD4 and CD8 204±37 cells/μL, 795±168 cells/μL, 408±102 cells/μL and 375±90 cells/μL, respectively. Two-yr PFT results were also robust with % predicted FVC, FEV1, TLC and DLCO of 89%, 84%, 82%, and 68%, respectively. All survivors are free of SCD symptoms and without signs of progression of multi-organ toxicity. One patient developed late hepatic SOS and died at day +59; one patient died at day +390 due to complications of CGVHD, and one patient died at day +141 of steroid refractory aGVHD, the remainder are alive and free of SCD symptoms with a median follow-up of +711 days (range, +231 to +1684 days). Most importantly, mean + SD HRQL score (0-100) reported at 1 yr for emotional, physical functioning, role, and global scores were 82.9±9.7 points, 82.8±15.8 points, 89.6±13.3 points, and 86±8.2 points, respectively.Early results indicate promising results in 1 yr OS, stable donor chimerism, and low incidence of acute and/or cGVHD after FHI HCT utilizing CD34 enrichment and CD3/MNC addback in high-risk SCD patients who lack a MSD or URD. A longer term follow-up is needed to assess long-term safety and outcomes. This research was supported by RO1FD004090-01A1. [Display omitted] DisclosuresWalters:AllCells, Inc: Other: Medical Director; bluebird bio: Research Funding; Sangamo Therapeutics: Consultancy; ViaCord Processing Lab: Other: Medical Director. Cairo:Jazz Pharmaceuticals: Speakers Bureau.

Stable to improved cardiac and pulmonary function in children with high-risk sickle cell disease following haploidentical stem cell transplantation.

Children with sickle cell disease (SCD) are at high-risk of progressive, chronic pulmonary and cardiac dysfunction. In this prospective multicenter Phase II trial of myeloimmunoablative conditioning followed by haploidentical stem cell transplantation in children with high-risk SCD, 19 patients, 2.0-21.0 years of age, were enrolled with one or more of the following: history of (1) overt stroke; (2) silent stroke; (3) elevated transcranial Doppler velocity; (4) multiple vaso-occlusive crises; and/or (5) two or more acute chest syndromes and received haploidentical transplants from 18 parental donors. Cardiac and pulmonary centralized cores were established. Pulmonary function results were expressed as percent of the median of healthy reference cohorts, matched for age, sex, height and race. At 2 years, pulmonary functions including forced expiratory volume (FEV), FEV1/ forced vital capacity (FVC), total lung capacity (TLC), diffusing capacity of lung for carbon monoxide (DLCO) were stable to improved compared to baseline values. Importantly, specific airway conductance was significantly improved at 2 years (p < 0.004). Left ventricular systolic function (fractional shortening) and tricuspid regurgitant velocity were stable at 2 years. These results demonstrate that haploidentical stem cell transplantation can stabilize or improve cardiopulmonary function in patients with SCD.

379 - Stable to Improved Long Term Cardiac and Pulmonary Function in Children, Adolescents, and Young Adults with High Risk Sickle Cell Disease Following Myeloimmunoablative Conditioning and Familial Haploidentical Stem Cell Transplantation

379 - Stable to Improved Long Term Cardiac and Pulmonary Function in Children, Adolescents, and Young Adults with High Risk Sickle Cell Disease Following Myeloimmunoablative Conditioning and Familial Haploidentical Stem Cell Transplantation

Characterization of Peripheral Blood Mononuclear Cells Addback Following CD34 Enrichment, Engraftment and T and NK Cells Immune Reconstitution in Patients with High Risk Sickle Cell Disease (SCD) (IND 14359)

Background: CD3/CD19 cell depletion (Barfiled RC, et al, Cytotherapy, 2004), αβ T-cell/CD19 cell depletion (Locatelli F, et al, Blood, 2017), CD34+ positive selection (Aversa F, et al, NEJM, 1998) are designed to deplete T cells and reduce AGVHD following allogeneic stem cell transplantation (AlloSCT). These approaches achieved low rates of AGVHD, but the grafts had few T and B cells. To improve immune reconstitution we undertook an alternative approach to addback small numbers and percentages of immune cells in the final HSCT product. We previously reported a very low incidence of AGVHD in pediatric recipients receiving CD34 enriched HPC products with peripheral blood mononuclear cells (PBMNC) addback containing a fixed dose of 2 x 105 CD3/kg from MUD donors (Geyer/Cairo et al, BJH, 2012). Recently we demonstrated that despite a 5 log depletion of T cells, PBMNC addback (fixed at 2 x 105 CD3/kg) facilitated rapid hematopoietic engraftment, high levels of donor chimerism and immune reconstitution with a low probability of Grade II-IV AGVHD. Patients had a 1 yr OS of 90% following familial haploidentical (FHI) CD34 Enriched Stem Cell Transplantation in patients with SCD (Cairo, JAMA Pediatr, 2020). Objective: To determine the final immune cell concentration following CD34 enrichment and PBMNC (2 x 105 CD3/kg) addback and determine the effect on engraftment and T and NK cell immune reconstitution. Methods: Patients and/or their guardians signed written informed consents and/or assents (NCT NCT02675959). CD34+ enrichment was performed using a CD34+ reagent system (CliniMACS; Miltenyi Biotec). Mononuclear cells (2 × 105 CD3 cells/kg of recipient body weight) were removed from the leukapheresis collection prior to CD34+ enrichment and were cryopreserved as a source of MNC addback (T cells). The addback products were analyzed for CD3+CD56- T cells, CD3-CD56+ NK cells, CD3+CD56+ NKT cells, Lin-CD123+ HLA-DR+ DC cells and Lin-CD11c+ HLA-DR+ DC cells by multicolor flow cytometry analysis. Th1/Th2 cytokines were measured by multiplex assays. T cell activity was measured by viral T cells IFN-g and plasma cytokines. NK function was measured by NK receptor expression by flow cytometry analysis and in vitro cytotoxicity. Results: We identified in the PBMNC addback, mean+SEM white blood cell (WBC) percentage of: CD3+ CD56- T cells = 56.4±5%; CD3- CD56+ NK cells = 4.6±1%; CD3+ CD56+ NKT cells = 5.1±0.6%; CD19+ B cells = 29.9±3.5%. Lin- WBC consisted of: CD123+ HLA-DR+ DC cells = 18.4±8.2%; CD11c+ HLA-DR+ DC cells = 6.0±3.0%. There were 20.0+9.1e6 T cells, 1.1+0.3e6 NK cells, 1.6+0.7 e6 NKT cells, 8.6+2.5e6 B cells, 1.2+0.6e6 CD123+DC and 0.8+0.5e6 CD11c DC in the final infused products (Fig.1). We found that percentages of IFN-g+ in CD4 cells in response to CMV (pp65), ADV (hexon) and EBV (BZLF1), ranged from 0.2%+0.1% to 0.5%+0.1%, while percentages of IFN-g+ in CD8 cells in response to the antigens ranged from 0.7%+0.3% to 3.7%+1.8% when examined at days 180, 270 and 365. NK (CD3- CD56+) reconstitution was extremely rapid and occurred as early as day 30 (35.5±8.6%, 2710+1624.4 cells/ul total cells; p&amp;lt;0.01 vs pre-t). There were no significant differences pre-HSCT vs day 365 in plasma cytokines (Th1 and Th2) and growth factors released including IFN-g, TNF-a, IL-18, IL-4, IL-5, IL-6, IL-10, G-CSF, MCP-1 and MIP1a. There was also robust expression of NK receptor expression including NK cytotoxicity receptors, NK KIR receptors, and C-type lectin-like receptors at day 30 as compared to pre-HSCT. NK cytotoxicity, as measured using PBMC cells from recipients at different time points against K562 (E:T=10:1), was also significantly increased at day 30 (26.2±2.8%) and day 180 (28.3±3%) vs pre-HSCT (16.1±2.1%) (p&amp;lt;0.01). As a NK cell activation marker, CD107a expression and granzyme B levels in gated NK cells peaked at day 30. Conclusion: PBMNC addback to CD34 enriched HPC products, with a final dose of 2 × 105 CD3 cells/kg, led to stem cell products with a diverse mixture of T, NK, NKT, DC1, and DC2 cells. Immune reconstitution following PBMNC addback to CD34 enriched cells resulted in excellent CD4 and CD8 responses to CMV, ADV and EBV, and rapid functional NK cell reconstitution (Supported by FDA R01FD004090 (MSC)). Disclosures Baxter-Lowe: CHLA: Current Employment, Membership on an entity's Board of Directors or advisory committees, Patents &amp; Royalties: Patents related to HLA typing, Research Funding. Johnson:Miltenyi Biotec: Research Funding; Cell Vault: Research Funding. Cairo:Miltenyi: Research Funding; Technology Inc/Miltenyi Biotec: Research Funding; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Nektar Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Actions of L-Glutamine vs. COVID-19 Suggest Additional Benefit in Sickle Cell Disease

Background:The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection associated with coronavirus disease 2019 (COVID-19) causes a 3- to 9-fold higher age-adjusted mortality in African American and Hispanic populations, the major US racial groups affected by sickle cell disease (SCD). The Centers for Disease Control designates SCD as a condition at increased risk for severe COVID-19. An urgent need for repurposing of available and safe therapeutics has been cited for such high-risk populations until vaccines are widely available.L-glutamine (GLN) ameliorates clinical pathology of SCD related to elements of COVID-19. Multiple systemic complications of COVID-19 are increasingly attributed to oxidative damage, a target which GLN regulates. Prescription-grade L-glutamine (PGLG) (Endari®, Emmaus Medical) decreases oxidative stress by increasing the ratio of reduced nicotinamide adenine dinucleotide (NAD) to total NAD, which may increase availability of reduced glutathione. PGLG also decreases red cell endothelial adhesion in patients with SCD. Of note, additional analysis of the phase 3 trial demonstrated a 63% lower occurrence of acute chest syndrome (ACS) in PGLG-treated SCD patients compared to control, which has important relevance in the pandemic. A recent report of two computational screens of FDA-approved therapeutics, directed to protein and chemistry targets and to gene expression changes induced by SARS-CoV-2, predicts glutathione and GLN are highly likely to confer benefit in COVID-19 (Kim, J Translat Med, 2020).Methods:We therefore reviewed reports of multi-system effects of GLN in experimental respiratory distress animal models and in ICU and COVID-19 patients. We focused on contributors to cytokine storm and acute respiratory distress syndrome (ARDS), the leading causes of mortality in COVID-19 (Huang, Lancet, 2020). We also conducted a clinical trial in hospitalized COVID-19 patients on ESPEN-recommended nutrition +/- GLN.Results:In experimental ARDS, sepsis, and endotoxin-induced lung injury, GLN decreases consolidation, pulmonary edema, and neutrophil infiltration and increases lung compliance, oxygen saturation, heat shock protein activation, and survival by 2.5-fold over saline controls (Perng WC, Clin Exp Pharmacol Physiol, 2010; Singleton, Crit Care Med, 2005). Patients with severe COVID-19 have increased proinflammatory cytokines; interleukin 6 (IL-6) levels predict and contribute to severity of COVID-19 (Yuki, Clin Immunol, 2020). GLN modulates inflammatory responses by suppressing C-reactive protein, IL-6, and TNF-α release; it also reduces IL-6 in murine studies (37% decrease,p< 0.05; Chuang, BMC Pulm Med, 2014), which could benefit COVID-19 patients.Myocardial injury occurs in up to 12% of COVID-19 patients directly with viral entry through ACE-2 receptors, microvascular damage, endothelial shedding, and inflammation-mediated damage, which GLN protects against (Shi, Eur Heart J, 2020; Shi, JAMA Cardiol, 2020; Shao, Pak J Med Sci, 2015). Inflammatory states lead to GLN consumption and negative GLN balance (Santos, Amino Acids, 2019). Deficient plasma GLN (< 420 µmol/L) is a defined risk for higher mortality in ICU and COVID-19 patients (Shen, Cell, 2020). Glutathione deficiency contributes to SARS-CoV-2 oxidative lung damage and severe disease (Polonikov, ACS Infect Dis, 2020).In a recent clinical trial, patients were confirmed to have SARS-CoV-2 by RT-PCR, had positive CT scans, and were admitted from a COVID-19 clinic. Both arms received ESPEN-recommended nutrition for COVID-19 alone or with GLN (10 grams, 3 times/day; see Table).Conclusions:GLN and glutathione deficiency contribute to COVID-19 severity, and GLN has salutary biologic actions on reducing lung pathology, mediators of cytokine storm, and myocardial injury in animal models, SCD, and ICU patients. GLN reduces severity in standard risk COVID-19 patientsafterinfection has occurred. These findings, combined with computational prediction of GLN benefit vs. COVID-19, support the hypothesis that PGLG treatmentprior toSARS-CoV-2 infection mayreducethe development of severe COVID-19 in SCD and perhaps other high-risk populations. The data as a whole provides a strong rationale for a controlled clinical trial of PGLG toreducesevere COVID-19 in high-risk SCD patients and improve outcomes if infection occurs.DisclosuresCengiz:Biruni University Medical Faculty:Current Employment;Istanbul University-Cerrahpasa Medical Faculty:Ended employment in the past 24 months.Yavuzer:Istanbul University-Cerrahpasa, Cerrahpasa School of Medicine, Department of Internal Medicine, Division of Geriatrics:Current Employment.Yavuzer:Biruni University Medical Faculty:Current Employment;Istanbul University-Cerrahpasa Mediacl Faculty:Ended employment in the past 24 months.Tang:Kaiser Permanente:Current Employment.Ward:Emmaus Medical, Inc.:Current Employment.Goodrow:Emmaus Medical, Inc.:Current Employment;Emmaus Life Sciences Shareholder:Current equity holder in publicly-traded company.Ludlum:Emmaus Life Sciences, Inc.:Consultancy, Current equity holder in publicly-traded company.Stark:Emmaus Life Sciences Shareholder:Current equity holder in publicly-traded company;Emmaus Medical, Inc:Current Employment.Perrine:Cetya Inc.:Membership on an entity’s Board of Directors or advisory committees;Phoenicia Bioscience:Current Employment, Current equity holder in private company, Membership on an entity’s Board of Directors or advisory committees;Phoenicia Therapeutics:Membership on an entity’s Board of Directors or advisory committees, Patents & Royalties;Boston University School of Medicine:Current Employment, Patents & Royalties;Viracta Therapeutics:Patents & Royalties.

Improved health care utilization and costs in transplanted versus non-transplanted adults with sickle cell disease.

Patients with sickle cell disease (SCD) have access to fewer health care resources and therapies compared to other diseases, which contributes to increased morbidity and health care utilization. We compared health care utilization (inpatient hospital days, emergency care visits) and health care-related costs between SCD adults that underwent hematopoietic stem cell transplantation (HSCT) using a nonmyeloblative conditioning regimen versus those referred for HSCT but did not proceed due to lack of an HLA-matched sibling donor, denial by insurance, red blood cell antibodies to the potential donor, or declining further evaluation. Between 8/2011 and 4/2016, 83 SCD patients were referred for allogeneic HSCT and 16 underwent the procedure. The HSCT and non-HSCT groups were similar by age, sex, prior SCD-related therapy and complications. Compared to pre HSCT, significantly fewer inpatient hospital days (median of 1 versus 22 days, P = 0.003) and emergency care visits (median of 1 versus 4 visits, P = 0.04) were observed by the 2nd year post-HSCT. Similar results were observed in comparison to the standard-of-care group (median of 1 versus 12 hospital days, P = 0.002; median of 1 versus 3 emergency visits, P = 0.03). Lower health care costs were observed by the 2nd year post-HSCT (median of $16,281 versus $64,634 pre-HSCT (P = 0.01) and versus $54,082 in the standard-of-care group (P = 0.05). A median reduction of -$20,833/patient/year (IQR, -$67,078-+$4,442/patient/year) in health care costs compared to pre-HSCT was observed in the 2nd year post-HSCT. In conclusion, allogeneic HSCT leads to improvements in health care utilization and costs compared to standard-of-care therapy in high-risk SCD adults.

Determining the Safety and Efficacy of Prophylactic Defibrotide Administration in Children, Adolescents, and Young Adults with Sickle Cell Disease Following Myeloimmunoablative Conditioning (MAC) and Haploidentical Stem Cell Transplantation Utilizing CD34+ Selection and T-Cell (CD3) Addback (IND127812)

<h3>Background</h3> Sickle cell disease (SCD) is a hemoglobinopathy and vasculopathy resulting in vaso-occlusive crises, chronic end-organ damage, and shortened life span. The only curative therapy is allogeneic stem cell transplant (AlloSCT) (Talano/Cairo, EJH, 2015). Unfortunately, only approximately 16% of the sickle cell population has an HLA matched unaffected sibling (Bhatia/Cairo, BMT, 2014). We have demonstrated the safety and efficacy of familial haploidentical transplants (FHI) in this population with 100% engraftment (Cairo et al, JAMA Peds, 2019). However, the incidence of sinusoidal obstructive syndrome (SOS) in SCD AlloSCT recipients is approximately 32% (McPherson, BMT, 2011). Defibrotide primarily targets endothelium and can reduce endothelial cell injury (Falanga et al, Leukemia, 2003 and Scallia et al, Clin Pharm, 1996). Corbaciolgu et al (Lancet 2012) demonstrated the safety and efficacy of prophylactic defibrotide in high-risk pediatric AlloSCT recipients to significantly reduce the incidence of SOS. <h3>Objective</h3> To determine the safety and efficacy of defibrotide prophylaxis for SOS in children, adolescents and young adults (CAYA) with high-risk SCD following MAC and FHI AlloSCT, utilizing CD34+ selection with CD3 addback. <h3>Design/Methods</h3> Patients with SCD aged 2 to 35 years with high-risk SCD (stroke, ≥2 acute chest syndrome in past 2 years, ≥3 pain crises in last 2 years, abnormal TCD study, ≥1 silent infarct lesion on MRI) were enrolled after being consented (NCT02675959). Patients were in two cohorts (2 to 17.99 years and 18 to 34.99 years of age) for age-based analysis and treatment (Table 1 and 2). All patients received a MAC regimen prior to receipt of an FHI with CD34+ selection and CD3 addback peripheral blood stem cell transplantation (PBSCT), as we have already demonstrated (Cairo et al, ASH, 2018). Defibrotide was given day -10 during conditioning through day +21 following transplant. Baseline studies of organ function and biomarkers were obtained prior to transplantation. <h3>Results</h3> We have enrolled eight patients, five in cohort 1 (median age 9.9 years) and three in cohort 2 (median age of 24 years) with a gender ratio (M/F) of 4/4. Patients had hemoglobin SS (n=7) or hemoglobin SC (n=1). Patients had either a maternal (n=7) or sibling (n=1) donor. Patients had early neutrophil engraftment (median day +11 (day +7 to day +14)). All tolerated 109 ± 11doses of defibrotide. There were no severe adverse or bleeding events probably or directly related to defibrotide. No patient developed SOS. <h3>Conclusion</h3> The preliminary data suggests defibrotide is safe and well tolerated in CAYA patients with high-risk SCD following MAC and FHI AlloSCT, utilizing CD34+ selection with CD3 addback. A larger cohort and/or follow-up will be required to confirm these preliminary findings. Supported by FDA R01FD004090 and Jazz Pharmaceuticals.

Stable to Improved Neurocognitive Outcomes in Children, Adolescents &amp; Young Adults with High-Risk Sickle Cell Disease (SCD) Who Have Undergone Familial Haploidentical (FHI) Stem Cell Transplantation: A Prospective Study from Pre HSCT Period to 2 Years Post HSCT (IND 14359)

<h3>Introduction</h3> The cognitive and neurological impairments associated with SCD that are due to cerebral vascular injury have been well documented (DeBaun et al, Blood, 2012). Brain abnormalities are evident on neuroimaging and cognitive domains in the areas of attention, memory, processing speed, executive functioning, and lower general intellectual functioning. Processing speed in particular is a vulnerable domain, with deficits mediating difficulties across other domains and is independently decreased in SCD patients unrelated to overt or silent infarctions (Stotesbury et al, Neurology, 2018). Van der Land et al suggests that there is a relationship between white matter tissue integrity and cognitive morbidity in SCD patients (British Journal of Hematology, 2015). Previous studies following reduced toxicity conditioning and matched sibling BMT in patients with SCD have demonstrated stable to improved CNS functioning (Walters et al, 2010, Biol BMT; Bhatia et al, BMT, 2014). <h3>Objectives</h3> We aimed to determine changes in neuroimaging and neurocognitive sequelae in individuals with high-risk SCD prior to and following myeloimmunoablative conditioning (MIAC) and FHI AlloSCT utilizing CD34 enrichment and T cell addback. <h3>Methods</h3> Haploidentical stem cell transplant with MIAC with CD34 enrichment was performed as previously described by Cairo et al (JAMA Peds, 2019). Participants had a baseline, 1 year and 2 year MRI that were reviewed by blinded central neuroimaging, neurocognitive screener (DIVERGT, Krull, et al) and an abbreviated, standardized neurocognitive test battery (IQ, memory, attention, language, motor, processing speed) over three time points (baseline, Day +365 and Day +730). Neurocognitive domain scores were calculated for each area of functioning in patients at each timepoint. <h3>Results</h3> Nineteen SCD patients were enrolled and received transplant (12 males, 7 females, mean age, 13.5, range 3-21). At baseline, seven patients had evidence of an overt stroke and four patients had evidence of a silent infarct. At 1 and 2 years post-transplant, there were no new overt and/or silent infarcts, and no new cerebral vasculopathy. Intellectual functioning, memory, language and attention/executive function remained stable to improved at year one and two, respectively (Table 1). Most importantly, processing speed was significantly improved at 2 years versus baseline (p<0.026). Language functioning approached significance at 2 years versus baseline (p<0.144) (Figure 1). <h3>Conclusions</h3> These preliminary studies suggest that MIAC followed by FHI AlloSCT utilizing CD34 enrichment and CD3 addback is protective against further CNS injury. Early HSCT has the potential to decrease or prevent cognitive decline and even improve neurocognitive functioning in high risk SCD recipients (supported by R01FD004090).

Sustained Donor Chimerism and Rapid Immune Cell Reconstitution with a Low Probability of Gvhd Following Familial Haploidentical (FHI) CD34 Enriched Stem Cell Transplantation with Pbmnc Addback in Patients with High Risk Sickle Cell Disease (SCD) (IND 14359)

Background Allogeneic stem cell transplantation (AlloSCT) from an HLA-matched sibling donor is the only known curative therapy in high-risk SCD patients (Talano/Cairo, EJH, 2015). Unfortunately only about 15% of high-risk SCD patients have an HLA-matched unaffected sibling donor. T cell depletion has been employed to reduce AGVHD. We reported a very low incidence of GVHD in pediatric recipients receiving CD34 enriched HPC products with PBMNC addback from MUD donors (Geyer/Cairo et al, BJH, 2012). Rapid NK cell reconstitution after AlloSCT is associated with a significant improvement in 1yr OS (Pical-Izard, BBMT, 2015). Recently, we reported promising results for high-risk SCD patients at 1 yr follow-up after FHI CD34 enriched/PBMNC with addback with the probability of 1-yr OS 88.2% (Cairo, et al, JAMA Peds, 2019). Objective To investigate donor chimerism, immune reconstitution and the incidence of GVHD in high-risk SCD patients following AlloSCT using FHI CD34 enrichment/PBMNC (2 × 105 CD3/kg) addback. Methods CD34 cells were enriched using the CliniMACS® system, kindly provided by Miltenyi Biotec, with a target dose of 10 × 106 CD34+ cells/kg. PBMNC were added back to the final CD34 product at a dose of 2 × 10*5 CD3/kg. Whole blood and CD71-enriched erythroid lineage chimerism were determined by STR. Immune cell, subset reconstitution, NK function, CD107a and granzyme B were assessed by flow cytometry as previously described (Geyer/Cairo et al. BJH, 2012, Chu/Cairo et al, Can Imm Res, 2015). Results The cumulative incidence of grade II-IV and late AGVHD was 6.2 % and moderate and/or severe CGVHD incidence was 6.7%, respectively (Fig. 1A). There was 100% engraftment of neutrophils and platelets. The median day post-HISCT to neutrophil and platelet engraftment was +9 and +19, respectively. Whole blood donor chimerism (mean±SEM) at 1-yr, 2-ys, and 3-ys post-HISCT was 97±1%, 97±1%, 97±1%, respectively (Fig.1B). Donor chimerism for CD71-enriched erythroid lineage cells (mean±SEM) at 1-yr, 2-yrs, 3-yrs post-HISCT was 97±2%, 98±1%, 98±1%, respectively (Fig.1B). The time to recovery of minimal normal levels for CD3 (800 cells/ul), CD4 (400 cells/ul), CD8 (200 cells/ul), & CD19 cells (200 cells/ul), was approximately 365, 365, 270, and 60 days post-HISCT, respectively (Fig.1C). NK reconstitution was rapid and peaked at d+30 (36±9%) with higher level of activating receptors NKp46, NKG2D & KIR2DS and inhibitory receptors NKG2A, CD94 and KIR2DL2/3. NK cytotoxicity against K562 (E:T = 10:1) peaked at d+30 and d+180 vs pre-transplant (p Conclusion The PBMNC addback facilitated rapid donor chimerism & immune reconstitution with a low probability of Grade II-IV AGVHD. The rapid NK reconstitution may have in part contributed to the excellent 1yr OS in this study (FDA R01FD004090 (MSC)). This approach is comparable to the method of CD3 TCRa/b-CD19 depletion.

Familial Haploidentical Stem Cell Transplant in Children and Adolescents With High-Risk Sickle Cell Disease

This phase 2 clinical trial in patients with high-risk sickle cell disease assesses the feasibility, safety, and 1-year event-free survival after myeloimmunoablative conditioning and familial haploidentical stem cell transplant.

Sustained Donor Chimerism and Rapid Immune Cell Reconstitution Following Familial Haploidentical (FHI) CD34 Enriched Stem Cell Transplantation with Pbmnc Addback in Patients with High Risk Sickle Cell Disease (SCD) (IND 14359)

Background: Allogeneic stem cell transplantation (AlloSCT) from an HLA-matched sibling donor is the only known curative therapy in patients with high-risk SCD (Talano/Cairo, EJH, 2015). Unfortunately only about 15% of high risk patients with SCD have an HLA-matched unaffected sibling donor. T cell depletion has been employed to reduce AGVHD e.g., CD3/CD19 cell depletion (Barfiled RC, et al, Cytotherapy, 2004), αβ T-cell/CD19 cell depletion (Locatelli F, et al, Blood, 2017), CD34+ positive selection (Aversa F, et al, NEJM, 1998). MUD transplantation in high-risk SCD recipients has shown unexpectedly high rates of CGVHD (Shenoy et al, Blood, 2016). We reported a very low incidence of acute and chronic GVHD in pediatric recipients receiving CD34 enriched HPC products with PB MNC addback with 2 x 105 CD3/kg from MUD donors (Geyer/Cairo et al, BJH, 2012). Furthermore, rapid NK cell reconstitution after AlloSCT is associated with a significant improvement in 1yr OS (Pical-Izard, BBMT, 2015; Dunbar et al, Hematologica, 2008). Recently, we reported promising results for high-risk SCD patients at 1 year follow-up after FHI CD34 enriched/PBMNC with addback AlloSCT with the probability of 1-year overall survival (OS) n=17; 88.2% (CI95: 60.6-96.9) (Talano/Cairo, ASH, 2017), expanding the donor pool and hopefully improving outcomes for high-risk patients with SCD. Objective: To investigate donor chimerism, immune cell reconstitution and NK cell function in high-risk patients with SCD following AlloSCT using FHI CD34 enrichment/PBMNC (2 x 105 CD3/kg) addback. Methods: Twenty-one eligible SCD patients (2-&lt;21 yrs) were enrolled. Nineteen patients received hydroxyurea, azathioprine, fludarabine, busulfan, thiotepa, cyclophosphamide, R-ATG, and TLI followed by FHI AlloSCT to date (Talano/Cairo, ASH, 2017). CD34 cells were enriched using the CliniMACS® system, kindly provided by Miltenyi Biotec, with a target dose of 10 x 106 CD34+ cells/kg with a PBMNC addback dose of 2x10*5 CD3/kg in the final product. Whole blood and RBC chimerism (estimated using CD71 to isolate an eythroid lineage-enriched fraction) were determined by STR. Immune cell and subset reconstitution was assessed by flow cytometry as previously described (Geyer/Cairo et al. BJH, 2012). NK function was determined by cytotoxic activity against K562 tumor targets at 10:1 E:T ratio by europium release assay and intracellular LAMP-1 (CD107a) and granzyme B expression by flow cytometry as previously described (Chu/Cairo et al, Can Imm Res, 2015). Results: There was 100% engraftment of neutrophils and platelets. The median day post-HISCT to neutrophil and platelet engraftment was +9 and +19, respectively. Whole blood donor chimerism (mean±SEM) at 1-year, 2-year, and 3-year post-HISCT was 97±1%, 97±1%, 97±1%, respectively (Fig.1). Donor chimerism for CD71+ RBCs (mean±SEM) at 1-year, 2-year, 3-year post-HISCT was 97±2%, 98±1%, 98±1%, respectively (Fig.1). Immune reconstitution of CD3, CD4, CD8, and CD19 was evaluated. The time to recovery of minimally normal levels post-HISCT of CD3 (800 cells/ul), CD4 (400 cells/ul), CD8 (200 cells/ul), and CD19 (200 cells/ul), was approximately 365, 365, 270, and 60 days post-HISCT (Fig.2), respectively. Probability of Grade II-IV AGVHD, CGVHD and 1 year EFS/OS was 6.2%, 6.7% and 90%, respectively. NK reconstitution was rapid and peaked at d+30 (36±9%, 2710cells/ml). NK cytotoxicity against K562 at a E:T=10:1 peaked at d+30 (26±3%) and d+180 (28±3%) vs at pre-t (16±2%) (p&lt;0.01) (Fig. 3A). Consistent with increased NK cytotoxicity, CD56dimCD3- subset was increased at d+30 vs pre- HISCT (p&lt;0.05). The NK activation marker, CD107a peaked at d+30 (38±9%) and d+180 (41±6%) (Fig.3B). More over, reconstituted NK cells expressed higher level of activating receptors NKp46 (24±9%), NKG2D (32±9%) and KIR2DS (8±3%) and inhibitory receptors NKG2A (33±9%), CD94 (28±9%) and KIR2DL2/3 (11±2%) at d+30 compared to other time points. Conclusion: Despite a 5 log depletion of T cells, the PBMNC addback (fixed at 2 x 105 CD3/kg) facilitated rapid donor chimerism and immune reconstitution with a low probability of Grade II-IV AGVHD. The rapid NK reconstitution may have in part contributed to the excellent 1yr OS in the FHI study. (Supported by FDA R01FD004090 (MSC)). Disclosures Cairo: Jazz Pharmaceuticals: Other: Advisory Board, Research Funding, Speakers Bureau; Osuka: Research Funding; Miltenyi: Other: MTA.

A Study of Nicotinamide With Oral Tetrahydrouridine and Decitabine to Treat High Risk Sickle Cell Disease

A Study of Nicotinamide With Oral Tetrahydrouridine and Decitabine to Treat High Risk Sickle Cell Disease