scholarly journals Severe Acute Complications of Sickle Cell Disease in Two Expert Referral Centers (UK and Italy): Natural History Studies Highlight Ongoing Unmet Need for Effective Disease Modifying or Curative Therapies

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3093-3093
Author(s):  
Raffaella Colombatti ◽  
Cynthia Sangarappillai ◽  
Muriel Soriano ◽  
Jonathan Bestwick ◽  
Will Hann ◽  
...  

Abstract Background: Hydroxyurea (HU) and chronic transfusion therapy (CTT) are the only disease modifying therapies (DMTs) currently available as standard of care in the UK and Italy for patients with sickle cell disease (SCD), with hematopoietic stem cell transplant (HSCT) available to a small fraction of patients. Few registries capture long-term follow up of real-world outcomes among patients with SCD and there is a need for natural history studies demonstrating morbidity and mortality under existing standard of care. The East London Newborn Sickle Cohort Study (ELNSCS) at the Royal London Hospital and the Sickle Cell Disease Cohort (SCDC) at the University of Padova (UNIPD) collect biomarker and clinical data on patients followed comprehensively at two expert referral centers and provide an opportunity to understand SCD real-world outcomes. Here, we report severe acute complications under standard of care during years when HU and CTT were widely available and accepted. Methods: Inclusion of patients in the ELNSCS required being born in a designated region in London, diagnosed by newborn screening between 1983-2018 and, for this analysis, followed during 2015-2018. Inclusion in the SCDC required being followed, for this analysis, at the UNIPD during 2016-2019. Analyses were restricted to patients with β Sβ S, β Sβ 0, and, for ELNSCS, β Sβ +. Data were entered into clinical databases at each site and subsequently validated against institutional records. Severe vaso-occlusive events (VOEs) were defined as events requiring admission (inpatient, ED, or hematology day unit) for acute chest syndrome (ACS), acute painful crisis, acute hepatic/splenic sequestration, acute ischaemic stroke, dactylitis and priapism. Statistical analysis was aligned between both sites. Patients were categorized into three mutually exclusive treatment groups (HU, CTT, no treatment) according to treatment during study period. Results: One hundred seventy-two patients in the ELNSCS and 62 patients at UNIPD met study inclusion criteria in the four-year analysis period. HbSS genotype accounted for 161 (93.6%) of ELNSCS cohort and 58 (93.5%) of UNIPD cohort. Median age at study entry was 11.6 (range 0.2 - 31.4) years in the ELNSCS and 7.66 (range 0.12 - 19.96) years at UNIPD. Median age differed across treatment groups; HU group tended to be younger, while CTT group tended to be older. According to institutional standards of care, 47 (27.3%) patients from the ELNSCS and 50 (80.6%) from UNIPD received HU, 53 (30.8%) from the ELNSCS and 8 (12.9%) from UNIPD received CTT, and 72 (41.9%) from the ELNSCS and 4 (6.5%) from UNIPD received no treatment during the four year study period. Differences in treatment allocation reflect slightly different patient populations and approaches to care at the two centers. Severe VOEs persist among patients in all three treatment groups at both sites. Of those receiving HU, 83.0% from the ELNSCS and 68.0% at UNIPD had ≥1 severe VOE, including 21.3% from the ELNSCS and 44.0% at UNIPD experiencing ≥1 ACS event. The rate of severe VOEs in the HU group was 0.75 (range 0 - 39.5) per patient year from the ELNSCS and 0.49 (range 0 - 3.00) per patient year from UNIPD. HU dosing and adherence will be explored using data collected on hematologic parameters. In the ELNSCS, of those receiving CTT, 60.4% experienced ≥1 severe VOE (20.8% had ≥1 ACS event); of those receiving no therapy, 56.9% experienced ≥1 severe VOE (11.1% had ≥1 ACS event). At UNIPD, severe VOEs were observed in 62.5% of the CTT group and 50% of the no treatment group, though sample sizes were very small. C onclusions: Despite receiving expert care in accordance with local and international guidelines at two large academic centers, a significant sub-group of patients continue to experience severe VOEs. Results show that real-world usage of HU and CTT may not be optimized and, even if optimized, some patients may continue to experience severe acute complications including ACS. Both cohorts confirm that implementation of existing standard of care is insufficient to prevent significant morbidity in patients with SCD. Findings suggest the need to introduce DMT early in life to reduce and prevent acute complications and minimize disease progression. There is a persistent need for maximizing effective DMTs, as well as further developing curative therapies such as HSCT and gene therapy for both pediatric and adult patients. Figure 1 Figure 1. Disclosures Colombatti: Novartis: Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; BlueBirdBio: Membership on an entity's Board of Directors or advisory committees, Research Funding. Chawla: BlueBirdBio: Current Employment. Puri-Sharma: BlueBirdBio: Current Employment. Walls: BlueBirdBio: Current Employment. Kommera: BlueBirdBio: Current Employment. Telfer: Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; Emmaus: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Addmedica: Membership on an entity's Board of Directors or advisory committees; ApoPharma: Membership on an entity's Board of Directors or advisory committees; Global Blood Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BlueBirdBio: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Terumo: Honoraria; Roche: Membership on an entity's Board of Directors or advisory committees.

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3113-3113
Author(s):  
Julie Kanter ◽  
Gerhard Hellemann ◽  
Alice J. Cohen ◽  
Deepa Manwani ◽  
Modupe Idowu ◽  
...  

Abstract Background: Vaso-occlusive crises (VOC) are the most common acute complication of sickle cell disease (SCD). Crizanlizumab, an anti-P-selectin monoclonal antibody, is an FDA-approved disease-modifying therapy (DMT) for SCD patients (pts) aged ≥16 yrs to reduce the frequency of VOC. To better understand its use and impact, the National Alliance for Sickle Cell Centers (NASCC) conducted a retrospective study of pts prescribed crizanlizumab from 11/2019-6/30/2021. NASCC is a non-profit organization formed to support SCD centers in delivering quality comprehensive care by setting and adopting specific standards and advocating for improved health outcomes in SCD. This study describes the largest real-world cohort of pts treated with crizanlizumab. Methods: This is a two-part study. Part 1 was to evaluate NASCC center crizanlizumab practice and to summarize data on insurance approval and the frequency of drug discontinuation. Part 2 includes pt level data to evaluate reasons for discontinuation and acute care utilization pre and post therapy. Acute care use includes day hospital/infusion, emergency department visits, and hospitalizations for VOC (excluding COVID-19). The index date for each pt is defined as the 1st crizanlizumab infusion date. Chart review (electronic health records) was used to identify all acute care visits 12 months pre-index and ≤12 months post index. Acute care data will be analyzed in aggregate. Evaluation of center-specific use of crizanlizumab, time to initial site level formulary approval and drug discontinuation were analyzed. Pt level data collection is ongoing to include sufficient time post index date. VOC characteristics will be summarized using medians, median differences (pre/post treatment), and 95% confidence intervals. Additional evaluation of effectiveness of crizanlizumab will include analysis based on number of doses received, pre-treatment VOC burden, concomitant hydroxyurea (HU) use and genotype. Results: Data includes pts prescribed crizanlizumab at 11 NASCC centers. Site- formulary approvals to use crizanlizumab varied from 12/2019-12/2020. As a result, the 1st pt to receive treatment at each site varied from 1/15/2020-1/20/2021. Mean time from site-level approval to first infusion was 77 days (range: 0-394). Over 50% of sites received insurance denials mainly due to "insufficient medical necessity" or "medication not covered by the prescription plan." Sites were able to successfully appeal denials for 71% of pts (Table 1). Treatment Delivery: Each site gives infusions over 30 minutes and the majority (64%) do not use pre-medication unless pts had reactions. Some sites use diphenhydramine/acetaminophen (3) or normal saline and ketorolac (1). All sites prescribe crizanlizumab to pts of all SCD genotypes. Pts Treated: 297 pts were prescribed crizanlizumab of whom 238 received ≥ 1 infusion. There was variation in number of pts/site (range 6-73, mean 21) due to time to site-level approval, insurance and pt population. Of these 238, 75 pts (32%) discontinued treatment (0-17 pts/site). Sites reported pts perceived lack of improvement or feeling their overall pain was increased, transportation issues and infusion related reactions (IRRs) characterized by pain as some of the reasons for discontinuation. Evaluation of real-world efficacy measured by changes in acute care utilization, including sub-analysis by genotype, pre-treatment VOC burden and concomitant HU use, are pending sample size dependent feasibility. Discussion: This is the first multi-center real-world analysis of crizanlizumab. Findings demonstrate some insurance barriers to therapy. The majority of pts who initiated crizanlizumab have remained on therapy; however, 1/3 of pts had lack of effect or barriers to care. Pt level data will include characteristics related to treatment failure or IRR. Improving the understanding of phenotype-specific response to novel therapies is essential in SCD. Conclusion: Post-approval therapies for rare diseases must undergo real-world evaluation to ensure study results translate to the community. NASCC uses defined criteria for multidisciplinary care for Alliance inclusion and findings reflect the use of DMT in such centers. This is the first NASCC study of DMT in SCD. Part 2 of the study will give early insights into the effectiveness of crizanlizumab; long term follow-up is needed for a full understanding of its utility in SCD. Figure 1 Figure 1. Disclosures Kanter: Fulcrum Therapeutics, Inc.: Consultancy; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Forma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Agios: Honoraria, Membership on an entity's Board of Directors or advisory committees; Beam: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Graphite Bio: Consultancy; GuidePoint Global: Honoraria; Fulcrum Tx: Consultancy. Manwani: Novartis: Consultancy. Idowu: Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Research Funding; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Forma Therapeutics, Inc.: Research Funding; Ironwood: Research Funding. Treadwell: National Alliance of Sickle Cell Centers: Other: Early Evaluation of the Use of Crizanlizumab in Sickle Cell Disease. Clay: GBT: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria. Little: Hemex Health, Inc.: Patents & Royalties; Biochip Labs: Patents & Royalties. Desai: Global Blood Therapeutics: Honoraria, Research Funding; Novartis: Research Funding, Speakers Bureau; Pfizer: Other: Publication Fee, Research Funding; Forma: Consultancy; Foundation for Sickle Cell Research: Honoraria. Lanzkron: Shire: Research Funding; Pfizer: Current holder of individual stocks in a privately-held company; Bluebird Bio: Consultancy; Teva: Current holder of individual stocks in a privately-held company; Novo Nordisk: Consultancy; GBT: Research Funding; Imara: Research Funding; CSL Behring: Research Funding; Novartis: Research Funding.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3100-3100
Author(s):  
Biree Andemariam ◽  
Maureen Achebe ◽  
E. Leila Jerome Clay ◽  
Richard A. Drachtman ◽  
Archana Sharma ◽  
...  

Abstract Background: Sickle cell disease (SCD) is an inherited systemic disorder in which sickle hemoglobin (HbS) polymerization triggers red blood cell sickling, chronic hemolytic anemia, and recurrent episodes of vaso-occlusion. SCD-related complications lead to acute and chronic life-threatening events, cumulative organ damage, disability, and early mortality. Voxelotor (Oxbryta ®) tablets are approved in the United States for treatment of SCD in adults and adolescents aged ≥12 years, based on the efficacy and safety data from the randomized, placebo-controlled, multicenter HOPE trial. Voxelotor is an oral, once-daily HbS-polymerization inhibitor that has been shown to increase hemoglobin (Hb) levels and reduce markers of hemolysis. The Retrospective Study to Evaluate Outcomes in Patients with Sickle Cell Disease Treated with Oxbryta (RETRO) is designed to collect, aggregate, and characterize real-world, retrospective laboratory and clinical data on adults and adolescents with SCD treated with voxelotor as part of their usual care at multiple clinical centers in the United States. Methods: RETRO is a multicenter, post-marketing, retrospective study of approximately 300 patients (aged ≥12 years) with SCD from 10 US study sites. Independent SCD expertise is provided by a steering committee to inform the design and conduct of the voxelotor registry. Clinical and laboratory data have been collected and aggregated 12 months before initiation of voxelotor treatment and compared with post-treatment data outcomes. Patients with documented SCD (all genotypes) who received voxelotor treatment for ≥2 consecutive weeks were included in this analysis. Only data available from patients' medical records (and other secondary data sources) 1 year before and up to 1 year after the first voxelotor dose were documented in de-identified case report forms via an electronic data capture system. Results: Forty-nine patients whose data were entered at 5 sites at the time of data cutoff (June 25, 2021) were included (mean age [SD]: 34.3 [12.91] years; 57.1% female; 85.7% HbSS and 6.1% HbSβ 0 genotype). Mean (SD) duration of voxelotor treatment was 48.1 (23.0) weeks. The initial prescribed voxelotor dose strengths (n, %) were 500 mg (4, 8.2%), 1000 mg (7, 14.3%), and 1500 mg (38, 77.6%). Rationale for prescription (n, %) included reduction of anemia (36, 73.5%), reduction in frequency of vaso-occlusive crises (23, 46.9%), reduction in pain (34, 69.4%), reduction in the need for blood transfusion (8, 16.3%) and other (5, 10.2%); more than 1 reason may have been selected. In 35 patients with recorded baseline and post-treatment Hb values, the peak observed post-treatment Hb (mean [SD]) was 9.4 (2.44) g/dL, an increase of 1.6 (1.5) g/dL from baseline (7.8 [2.02] g/dL). Fifty percent (11/22) of patients had a clinical response (Hb increase of >1.0 g/dL from baseline) within 12 months of voxelotor treatment. Per-patient peak changes in Hb during the study period showed that 62.9% of patients experienced a response at some time up to 12 months during treatment (Figure). Change in hemolytic markers was also evaluated. In patients with recorded baseline and post-treatment reticulocyte percentage (N=19) and indirect bilirubin (N=24), the mean (SD) absolute post-treatment value was 7.4% (4.65%) for reticulocyte percentage, a decrease of 4.9% (6.63%) compared with baseline (12.4% [8.32%]), and 1.9 (1.66) mg/dL for indirect bilirubin, a decrease of 17.7 (81.83) mg/dL compared with baseline (19.6 [81.82] mg/dL). The most common non-SCD-related treatment-emergent adverse events (AEs) were diarrhea, headache, and rash (Table); 19 (38.8%) patients reported ≥1 AE, and most non-SCD-related AEs were mild in severity. Conclusions: RETRO is the first multicenter, retrospective study to examine the real-world effectiveness of voxelotor and describe the observed changes in laboratory and clinical outcomes after ≥2 weeks of therapy. This study shows that voxelotor treatment was associated with increased Hb levels and decreased hemolytic markers. The safety data are consistent with those from the HOPE trial. Further evaluation is needed, with additional data from all 10 sites, and will be presented later. Funding: This study was supported by Global Blood Therapeutics. Figure 1 Figure 1. Disclosures Achebe: Fulcrum Therapeutics: Consultancy; Pharmacosmos: Membership on an entity's Board of Directors or advisory committees; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees. Clay: GBT: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria. Nero: Global Blood Therapeutics: Consultancy; Editas Medicine: Consultancy; bluebird bio: Consultancy; Novartis: Consultancy. Osunkwo: Terumo: Consultancy; Global Blood Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Acceleron: Consultancy; Forma Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Health and Services Administration: Research Funding; Patient Centered Outcomes Research Instituted: Research Funding; Micella Biopharma: Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Chiesi: Consultancy; Cyclerion: Consultancy; Emmaus: Consultancy. Idowu: Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Ironwood: Research Funding; Forma Therapeutics, Inc.: Research Funding; Pfizer: Research Funding. Shah: Novartis: Research Funding, Speakers Bureau; Alexion: Speakers Bureau; Emmaus: Consultancy; GBT: Consultancy, Research Funding, Speakers Bureau; Guidepoint Global: Consultancy; CSL Behring: Consultancy; GLG: Consultancy; Bluebird Bio: Consultancy. Curtis: GBT: Consultancy. Minniti: Bluebird Bio: Other: Endpoint adjudicator ; F. Hoffmann-La Roche Ltd: Consultancy; Chiesi: Consultancy; Novo Nordisk: Consultancy; Forma: Consultancy; Novartis: Consultancy; GBT: Consultancy; CSL Behring: Other: Endpoint adjudicator .


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3091-3091
Author(s):  
Michael Rabaza ◽  
Maria Armila Ruiz ◽  
Liana Posch ◽  
Faiz Ahmed Hussain ◽  
Franklin Njoku ◽  
...  

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


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 37-37
Author(s):  
Rita V Masese ◽  
Dominique Bulgin ◽  
Mitchell Knisely ◽  
Liliana Preiss ◽  
Eleanor Stevenson ◽  
...  

Introduction Sickle cell disease (SCD) is the most common inherited blood disorders in the United States. The disease predominantly affects African Americans with 1 out of every 365 individuals born with SCD. The disease is characterized by vascular inflammation and vaso-occlusion leading to numerous complications and multi-organ dysfunction. Previous studies have shown women with SCD tend to outlive their male counterparts. Other than the increased life expectancy, sex-based clinical outcome differences in SCD remain largely unknown. To better characterize sex-based differences in SCD, we assessed sociodemographic characteristics, pain, treatment characteristics, laboratory measures and complications among males and females currently enrolled in the Sickle Cell Disease Implementation Consortium (SCDIC) registry. Methods The SCDIC consists of eight academic and comprehensive SCD centers, and one data-coordinating center that received funding from the National Heart Lung and Blood Institute to improve outcomes for individuals with SCD. Participants were eligible for the enrollment in the SCDIC registry if they were 15 to 45 years of age and had a confirmed diagnosis of SCD. Participants were excluded if they had sickle cell trait or had a successful bone marrow transplant. Enrolled participants completed surveys. Data were also abstracted from the participants' medical records. Data were entered into a REDCap database and analyzed using SAS version 9.4 (SAS Institute; Cary, NC). Categorical variables were presented as frequencies and percentages, continuous variables were presented as medians and interquartile ranges (IQR) or means and standard deviations. Categorical variables were analyzed using Chi-Square or Fisher exact tests when appropriate. Continuous variables were compared using the Mann-Whitney U test or independent sample t-tests depending on the distribution. A two-sided p-value less than 0.05 was deemed significant. Results A total of 2,124 participants were included in the study. The mean (SD) age of our participants was 27.8 (7.9) years. Almost all (95.6%) were Africa American, female (56%) and had hemoglobin SS (68.2%) SCD genotype. More males (55.4 % vs. 44.6%, p <0.0001) were taking hydroxyurea. Females had significantly worse reports of pain frequency and severity (p=0.0002 and <0.0001 respectively), more vaso-occlusive episodes (p=0.01) and a higher occurrence of 3 or more hospital admissions in the past year (30.9 % vs. 25.5, p= 0.03). Males had significantly more skin ulcers and respiratory, musculoskeletal, genitourinary and cardiovascular complications while females had more anxiety, depression and autoimmune conditions. Males also had significantly higher creatinine, blood urea nitrogen, albumin and liver enzymes (alkaline phosphatase, aspartate and alanine aminotransferases). Females had higher fetal hemoglobin levels with and without hydroxyurea use. There were no statistical differences in ethnicity, marital and employment status. Conclusion Key differences in SCD presentation and occurrence of complications exist among males and females. Females had higher rates of depression and anxiety while males had more chronic end-organ complications that are life threatening. Our findings emphasize the need for stratification of data analysis by sex in future SCD studies. Disclosures Hankins: Global Blood Therapeutics: Consultancy, Research Funding; National Heart, Lung, and Blood Institute: Honoraria, Research Funding; LINKS Incorporate Foundation: Research Funding; American Society of Pediatric Hematology/Oncology: Honoraria; MJH Life Sciences: Consultancy, Patents & Royalties; UptoDate: Consultancy; Novartis: Research Funding. Treadwell:UpToDate: Honoraria; Global Blood Therapeutics: Consultancy. King:Tioma Therapuetics: Consultancy; WUGEN: Current equity holder in private company; RiverVest: Consultancy; Celgene: Consultancy; Cell Works: Consultancy; Incyte: Consultancy; Magenta Therapeutics: Membership on an entity's Board of Directors or advisory committees; Bioline: Consultancy; Novimmune: Research Funding; Amphivena Therapeutics: Research Funding. Gordeuk:CSL Behring: Consultancy, Research Funding; Global Blood Therapeutics: Consultancy, Research Funding; Imara: Research Funding; Ironwood: Research Funding; Novartis: Consultancy. Kanter:bluebird bio, inc: Consultancy, Honoraria; SCDAA Medical and Research Advisory Board: Membership on an entity's Board of Directors or advisory committees; AGIOS: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy; Sanofi: Consultancy; Medscape: Honoraria; Guidepoint Global: Honoraria; GLG: Honoraria; Jeffries: Honoraria; Cowen: Honoraria; Wells Fargo: Honoraria; NHLBI Sickle Cell Advisory Board: Membership on an entity's Board of Directors or advisory committees; BEAM: Membership on an entity's Board of Directors or advisory committees. Glassberg:Eli Lilly and Company: Research Funding; Pfizer: Research Funding; Global Blood Therapeutics: Consultancy. Shah:Bluebird Bio: Consultancy; Novartis: Consultancy, Research Funding, Speakers Bureau; Global Blood Therapeutics: Consultancy, Research Funding, Speakers Bureau; CSL Behring: Consultancy; Alexion: Speakers Bureau.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1013-1013
Author(s):  
Frédéric Galactéros ◽  
Ersi Voskaridou ◽  
Anoosha Habibi ◽  
Giovanna Cannas ◽  
Laure Joseph ◽  
...  

Hydroxyurea (HU) is approved in the EU and USA for prevention of vaso-occlusive crises (VOC) including acute chest syndromes (ACS) in patients over 2 years with sickle-cell disease (SCD). The major benefits of HU in SCD are directly related to its abilities to increase HbF, decrease sickling of red blood cells and hemolysis, leading to reduction of vaso-occlusive episodes, need for blood transfusions and consequently reduction of morbidity and mortality. Adherence to the treatment is paramount for effectiveness, but in spite of proven benefits, barriers to adherence persist.[1] ESCORT-HU study (European Sickle Cell Disease COhoRT - HydroxyUrea), is a multicentric, prospective, non-interventional European study designed to evaluate the safety profile of HU in real life. Patients were enrolled from January 2009 to June 2017 with a follow-up of up to 10 years. All interruptions and resumptions of HU treatment exceeding 15 days were recorded in this study. We hereby present the analysis of the group of patients who self-discontinued HU at least once during the study before informing their caregiver, with a view to identify potential barriers to long-term adherence. In total, 1906 patients were enrolled in ESCORT-HU from 63 centers in France, Germany, Greece and Italy. Of these, 619 patients (32%) stopped HU for over 15 days at least once, and around a third (11% of all patients) were due to patient's will. The mean duration of HU treatment before the first discontinuation was 4.8 ± 5.1 years. Data are summarized in table 1. Compared to the rest of the cohort, the 'treatment discontinuation' group had similar distribution by gender and indication for HU prescription, but a higher proportion of adults stopped HU more than 15 days. It is notable that the proportion of patients with SC genotype was higher in the 'treatment discontinuation' group (4.5% vs 1.7%). The patients in the 'treatment discontinuation' group had more frequent SCD symptoms before enrolment in the study (table 2). Hematological and clinical improvement compared to the baseline was observed in both groups. However, average mean Corpuscular Volume (MCV) and Fetal Hemoglobin percentage (HbF%) were lower and mean percentages of patients with SCD symptoms were higher over the three years of follow-up in the 'treatment discontinuation' group, suggesting that HU daily dose was insufficient (table 2). Sixty patients have no treatment resumption date reported which suggest a permanent interruption of their treatment. Among them 32% preferred to switch to another HU medicinal product and 13% have safety issue (table 3). Understanding and managing self-discontinuation of HU before taking medical advice is challenging for the physician. It is tempting to speculate that it may be due, at least in part, to lack of effectiveness potentially due to an underdosage of the treatment. Resistance to the treatment may also be suggested based on past literature data revealing a great variability in the response (determined by HbF%) to HU therapy. There is evidence that genetic modifiers affect individual response to HU.[2],[3] Finally, weariness from long-term use may also explain the patient's wish to discontinue HU. But treatment at optimal effective should be the primary goal of caregivers. [1]Smaldone A., Manwani D., Green NS, Greater number of perceived barriers to hydroxyurea associated with poorer health-related quality of life in youth with sickle cell disease, Pediatr Blood Cancer. 2019 [2] Steinberg MH, Voskaridou E, Kutlar A, Loukopoulos D, Koshy M, et al. (2003). Concordant fetal hemoglobin response to hydroxyurea in siblings with sickle cell disease. Am J Hematol 72: 121-126 [3] Ware RE, Despotovic JM, Mortier NA, Flanagan JM, He J, et al. (2011) Pharmacokinetics, pharmacodynamics, and pharmacogenetics of hydroxyurea treatment for children with sickle cell anemia. Blood 118: 4985-4991 Disclosures Galactéros: Addmedica: Membership on an entity's Board of Directors or advisory committees. Voskaridou:Celgene Corporation: Consultancy, Research Funding; Protagonist: Research Funding; Genesis: Consultancy, Research Funding; Acceleron: Consultancy, Research Funding; Addmedica: Membership on an entity's Board of Directors or advisory committees. Cannas:Addmedica: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 967-967
Author(s):  
Nicolas Hebert ◽  
Erica B. Esrick ◽  
Myriam Armant ◽  
Christian Brendel ◽  
Marioara Felicia Ciuculescu ◽  
...  

Abstract NH and EE equally contributed. ADW and PB co-signed. The expression of fetal hemoglobin (HbF) is one of the main targets of sickle cell disease treatment, as it inhibits the polymerization of hemoglobin S. The hypothesis of an inhibitory threshold of HbF per red blood cell (RBC) has been suggested, 1 although not well defined, as the overall percentage of HbF does not reflect the heterogeneous distribution of HbF per cell. Likewise, the qualitative analysis of RBCs containing HbF, called F cells, is neither reproducible nor clinically interpretable, due to low expression. 2 We have developed a technique for measuring the amount of HbF per cell, to determine thresholds of HbF expression per RBC correlated with clinical and biological effects. 2 Among genes controlling its expression, BCL11A has a major repressive effect on the expression of gamma globin/HbF during the fetal to adult hemoglobin switch. Post-transcriptional silencing of BCL11A, using lentivirus expression of a shRNA embedded in a microRNA architecture (shmiR) to re-activate γ-globin expression, is safe and demonstrates high levels of %HbF in a pilot clinical study (NCT 03282656). 3 Here, we show the quantitative measurement of HbF per RBC and reticulocyte. Methods: During patient follow-up, HbF quantification per single cell RBC was performed using a fluorescent HbF antibody. 2 Addition of an anti-CD71 fluorescent antibody allowed selection of reticulocyte sub-populations for determining their HbF content. Fold-increase in percentage of RBC versus percentage of reticulocyte were calculated. Kinetics of HbF/RBC and HbF/Reticulocyte were modeled using mixed effects polynomial linear regression to account for the correlation between repeated data over time. Results: With a median follow-up of 15 months [12-20] after gene transfer, figure 1 shows the mathematical modeling of single-RBC HbF measurement representing RBC percentage containing at least 2, 4, 6, 8 and 10 pg of HbF. Percentage of RBC above each threshold was higher compared to 14 hydroxyurea treated patients for 6 months. Figure 2 shows fold increase between reticulocytes and RBCs with same thresholds of HbF/cell. For low thresholds, RBCs were found in same percentage as reticulocytes whereas RBCs containing increasing levels of HbF were found in higher percentage than reticulocytes, until 6pg/cell showing a clear selective advantage for red cells with a threshold ≥ 6pg/cell of HbF. Figure 3 shows different kinetics of HbF increase according to two different transduction strategies with 2 enhancers in patients 2-4 compared to one enhancer in patients 6-8. Conclusion: BCL11A down-regulation in six clinical trial subjects was associated with an in vivo selection process RBCs with ≥ 6pg HbF per cell attained with different engraftment kinetics, depending on transduction processes, and ultimately stable high level and broadly distributed HbF. 1 Steinberg MH, Chui DH, Dover GJ, Sebastiani P, Alsultan A. Fetal hemoglobin in sickle cell anemia: a glass half full? Blood. 2014 Jan 23;123(4):481-5. 2 Hebert N, Rakotoson MG, Bodivit G, et al. Individual red blood cell fetal hemoglobin quantification allows to determine protective thresholds in sickle cell disease. Am. J. Hematol. 3 Esrick EB, Lehmann LE, Biffi A, et al. Post-Transcriptional Genetic Silencing of BCL11A to Treat Sickle Cell Disease. N. Engl. J. Med. 2021;384(3):205-215. Figure 1 Figure 1. Disclosures Esrick: bluebird bio: Consultancy. Audureau: GBT: Honoraria. Higgins: Sebia, Inc.: Honoraria; Danaher Diagnostics: Consultancy. Williams: BioMarin: Membership on an entity's Board of Directors or advisory committees, Other: Insertion Site Advisory Board; Geneception: Membership on an entity's Board of Directors or advisory committees, Other: Scientific Advisory Board; Emerging Therapy Solutions: Membership on an entity's Board of Directors or advisory committees, Other: Chief Scientific Chair; Beam Therapeutics: Membership on an entity's Board of Directors or advisory committees, Other: Scientific Advisory Board; Alerion Biosciences: Other: Co-founder (now licensed to Avro Bio, potential for future milestones/royalties); Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Steering Committee, Novartis ETB115E2201 (eltrombopag in aplastic anemia). Advisory fees donated to NAPAAC.; Orchard Therapeutics: Membership on an entity's Board of Directors or advisory committees, Other: Membership on a safety advisory board (SAB): SAB position ended 05/20/2021. Co-founder , Patents & Royalties: Potential for future royalty/milestone income, X-SCID. Provided GMP vector for clinical trial, Research Funding; bluebird bio: Membership on an entity's Board of Directors or advisory committees, Other: Insertion Site Analysis Advisory Board, Patents & Royalties: BCH licensed certain IP relevant to hemoglobinopathies to bluebird bio. The current license includes the potential for future royalty/milestone income. Bluebird has indicated they will not pursue this as a clinical program and BCH is negotiating return of, Research Funding. Bartolucci: AGIOS: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Lecture fees, Steering committee, Research Funding; Jazz Pharma: Other: Lecture fees; Emmaus: Consultancy; Addmedica: Consultancy, Other: Lecture fees, Research Funding; INNOVHEM: Other: Co-founder; Hemanext: Consultancy; GBT: Consultancy; Bluebird: Consultancy, Research Funding; F. Hoffmann-La Roche Ltd: Consultancy; Fabre Foundation: Research Funding.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2048-2048
Author(s):  
Ondine Walter ◽  
Pierre Cougoul ◽  
Julien Maquet ◽  
Pablo Bartolucci ◽  
Maryse Lapeyre-Mestre ◽  
...  

Abstract Introduction : Sickle cell disease (SCD) is an inherited disorder which affects 300,000 newborns per year. Vaso-occlusive episodes (VOEs) cause an important morbi-mortality and a decreased quality of life in patients with SCD. Some risk factors of VOE are well known, like infection, cold exposure, stress, pulmonary diseases and dehydration. Exposure to systemic corticosteroids has been suspected to increase the occurrence of VOEs in few case reports or series. However, no comparative study has been conducted to demonstrate this risk which is still debated, resulting in discrepancies among guidelines on SCD management. This study aimed to assess the risk of hospitalization for VOE associated with out-hospital exposure to systemic corticosteroids in patients with SCD in France. Methods : Data source was the French national health insurance system database, named SNDS (Système National des Données de Santé) between 2010 and 2018. The SNDS links sociodemographic, out- and in-hospital data for the entire French population (>66 million inhabitants). The study population consisted in all patients with SCD with at least one hospitalization for VOE during the study period, identified with a primary discharge diagnosis of VOE (D57.0 code of the international classification of disease, 10 th version; positive predictive value: 98.6%). All genotypes (homozygous SS-SCD and double-heterozygous SCD) were included. Because we assessed out-hospital exposure to corticosteroids, patients hospitalized during the three months before the first VOE were excluded. We performed a case-case-time-control study (Figure 1). This self-controlled design results in self-adjustment for time-independent confounders, including genotype. The outcome was the first hospitalization for VOE. The exposure to oral and injectable corticosteroids, identified using out-hospital reimbursement data, was assessed during a case period (28 days before the outcome) compared to the exposure during a control period (28 days, starting 84 days before the outcome). The same comparison was made among future cases (matched patients hospitalized for VOE the year after the given case), in order to adjust for the trend of exposure to corticosteroids (calendar variations of corticosteroid exposure). Results : Overall, 5,151 cases of VOEs were included in the main analysis. Median age at first VOE was 16.9 years; 317 (6.2%) patients were exposed to corticosteroids during the case period. In the main analysis, corticosteroid exposure was significantly associated with the occurrence of hospitalizations for VOEs: adjusted Odds Ratio (aOR): 3.81, 95% confidence interval (95% CI): 2.44 to 5.61. In patients exposed to hydroxyurea, the aOR was 2.61, 95% CI: 1.07 to 6.39, compared with an aOR of 4.00, 95% CI: 2.53 to 6.30 in unexposed patients. In the subgroup analysis by age, the aOR was 2.81, 95% CI: 1.49 to 5.30 in children, and 4.45, 95% CI: 2.37 to 8.37 in adults. The results were consistent in all sensitivity analyses. Conclusion : This study showed an association between outpatient exposure to systemic corticosteroids with an increased risk of hospitalization for VOE, in both adults and children. Hydroxyurea may reduce this risk in adults. Figure 1 Figure 1. Disclosures Bartolucci: GBT: Consultancy; Emmaus: Consultancy; Fabre Foundation: Research Funding; AGIOS: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Lecture fees, Steering committee, Research Funding; Jazz Pharma: Other: Lecture fees; INNOVHEM: Other: Co-founder; Bluebird: Consultancy, Research Funding; F. Hoffmann-La Roche Ltd: Consultancy; Hemanext: Consultancy; Addmedica: Consultancy, Other: Lecture fees, Research Funding. Moulis: Argenx: Membership on an entity's Board of Directors or advisory committees; Sobi: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Grifols: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 31-32
Author(s):  
Nirmish Shah ◽  
Ahmar Urooj Zaidi ◽  
Michael U. Callaghan ◽  
Darla Liles ◽  
Clarissa E. Johnson ◽  
...  

Background: Sickle cell disease (SCD) is a chronic illness characterized by anemia, recurrent severe pain and recurrent organ damage, affecting approximately 100,000 persons in the United States. Prior to November 2019, FDA approved SCD disease-modifying treatments included only hydroxyurea (HU) and L-glutamine. However, voxelotor (Oxbryta®) was recently approved under an accelerated approval based on the HOPE study for the treatment of adult and pediatric patients with SCD 12 years of age and older. We aimed to provide real world evidence of the types of patients prescribed voxelotor and preliminary evidence of potential treatment effects. Methods: Patient records were reviewed from five medical centers with comprehensive sickle cell care. All patients prescribed voxelotor from Nov 25, 2019 to July 31, 2020 were included in our analysis. Data reviewed included: patient demographics, hydroxyurea use, as well as pre- and post- voxelotor changes on red cell transfusion number, vaso-occlusive crisis (VOC) and hemoglobin (Hb) values. In addition, voxelotor dosage changes, side effects, and patients perception on impact on their health were recorded. Descriptive and summary statistics were used to provide results. Results: We reviewed data from 60 patients (18 pediatric and 42 adult), across the five centers, who were prescribed voxelotor. Mean age was 33 (SD 13.8) years old with 63% female patients. All patients were African-American/Black and 96% were HbSS (2% Hb SC and 2% HbSOArab). Eighty (80)% were on hydroxyurea, 20% were on chronic transfusions, and 10% were on erythropoietin stimulating agents when prescribed voxelotor. Mean baseline hemoglobin during the 3 months prior to initiation was 7.38 g/dL (SD 1.46) with all patients started at the recommended dose of 1500mg. Annualized VOC events for the year prior to starting voxelotor was 0.62 (SD) or 7.44 VOCs per year. Across all sites, 31 patients were prescribed voxelotor but had either not initiated drug, not returned for follow up labs at time of analysis, or refused to take drug once approved (n=1). Nine patients had only 1 month of follow labs to review and an additional 18 patients with 3 months of follow up labs. These 27 patients were followed for an average of 6.0 months (SD 7.7) on treatment with 4 patients (15%) requiring dose adjustment to 1000mg. Dose adjustments were for side effects including abdominal pain, diarrhea, loose stools and nausea/vomiting. One patient had dosing changed from daily to three times a day. Average hemoglobin during steady state after 1 and 3 months of treatment were 8.6 g/dL (SD 1.8) and 8.0 g/dL (SD 1.8), respectively. In addition, 52% increased by 1g/dL at 1 month (n=21) and 44% increased by 1g/dL at 3 months (n=18). The mean maximum hemoglobin obtained during the 3-month period following initiation of voxelotor was 8.9 (SD 2.1) g/dL. During follow up visits, several patients reported 'more energy' and improvement in 'morning achiness' and 'quality of life', while a few patients noted no change in stamina or well-being. Three patients (5%) had drug discontinued due to becoming pregnant, unexplained elevation of liver enzymes, and due to excessive abdominal pain and nausea. Annualized VOC rates after voxelotor initiation were numerically decreased, although limited by short follow up. Conclusion: We present real world evidence of prescribing patterns and initial outcomes from the use of newly approved voxelotor. We found the majority of patients prescribed voxelotor were the HbSS genotype, on hydroxyurea, and with a mean baseline Hb <7.5 g/dL, indicating an initial focus on more anemic patients. Interestingly, one-fifth of the prescribed patients where on chronic transfusions. Consistent with the HOPE trial, the average Hb levels was found to have increased at 1 month and 3-month follow up. Our preliminary results support an overall increase in hemoglobin in patients treated with voxelotor and we aim to continue following patients over a longer follow up period. This provides important real-world evidence for this newly approved disease-modifying therapy for SCD. Disclosures Shah: Alexion: Speakers Bureau; CSL Behring: Consultancy; Novartis: Consultancy, Research Funding, Speakers Bureau; Global Blood Therapeutics: Consultancy, Research Funding, Speakers Bureau; Bluebird Bio: Consultancy. Zaidi:Global Blood Therapeutics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Emmaus Life Sciences: Consultancy, Honoraria; Imara: Consultancy, Honoraria; bluebird bio: Consultancy, Honoraria; Cyclerion: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Callaghan:Grifols: Honoraria, Membership on an entity's Board of Directors or advisory committees; Octapharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche/Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Site Investigator/sub-I Clinical Trial, Speakers Bureau; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Site Investigator/sub-I Clinical Trial, Research Funding; Sancillio: Other; Bayer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; NovoNordisk: Other, Speakers Bureau; Biomarin: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Site Investigator/sub-I Clinical Trial, Speakers Bureau; Global Blood Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Speakers Bureau; Alnylum: Current equity holder in publicly-traded company; Bioverativ: Membership on an entity's Board of Directors or advisory committees; Spark: Honoraria, Membership on an entity's Board of Directors or advisory committees; Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Hema Biologics: Honoraria, Membership on an entity's Board of Directors or advisory committees. De Castro:Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees; FORMA Therapeutics: Membership on an entity's Board of Directors or advisory committees; GlycoMimetics: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 509-509 ◽  
Author(s):  
Clark Brown ◽  
Carolyn Hoppe ◽  
Adlette Inati ◽  
Miguel R. Abboud ◽  
Winfred Wang ◽  
...  

Abstract Background: Sickle cell disease (SCD) is a genetic disorder caused by a mutated hemoglobin S (HbS) that polymerizes in the deoxygenated state and triggers the downstream effects of red blood cell deformation (sickling), hemolysis, vaso-occlusion, and inflammation. Injury from SCD starts in infancy and accumulates over a lifetime causing end-organ damage and ischemic tissue injury, leading to fatigue, pain (vaso-occlusive crisis), and other clinical complications that are underrecognized, undertreated, and associated with early death. Voxelotor is an oral, once-daily therapy that modulates hemoglobin (Hb) affinity for oxygen, thereby inhibiting Hb polymerization. GBT440-007 is a phase 2a study designed to assess the safety, pharmacokinetics (PK), and efficacy of voxelotor in pediatric patients with SCD (HbSS or HbSβ0 thalassemia). Methods: This ongoing study is evaluating multiple doses of voxelotor at 2 dose levels, 900 mg/day and 1500 mg/day, for 24 weeks in adolescents aged 12 to 17 years. The primary objective is to assess the effect of voxelotor on anemia. Secondary objectives include the effects on clinical measures of hemolysis, PK (PK parameters determined using population PK analysis), cerebral blood flow as assessed by transcranial doppler ultrasound (TCD), and safety. Results: Results for adolescents treated with 900 mg/day have been previously reported. As of June 18, 2018, partial data are available for 13 patients (9 females and 4 males). The median age was 14 years (range, 12-17 years) and median weight was 47 kg (range, 31-72 kg). All participants were on hydroxyurea (HU), and 46% had 2 or more painful crises (range, 2-15) in the year prior to enrollment. The median baseline TCD flow velocity was 112 cm/s (range, 92-177 cm/s), and all were less than 135 cm/s at baseline except for 1 with a baseline of 177 cm/s. Data for measures of hemolysis and TCD are available for 5 adolescents who received voxelotor for 12 weeks. The median increase in Hb was 1.0 g/dL at 12 weeks (Table). Median reductions in reticulocytes and indirect bilirubin were 29% and 18%, respectively (Table), consistent with previously reported results of voxelotor in adults with SCD. Preliminary data suggest linear PK up to 1500 mg, the highest dose evaluated. The adolescent with a baseline conditional TCD (177 cm/s of the bifurcation of the internal carotid artery) on background HU at the maximum tolerated dose (29 mg/kg) had a reduction in TCD flow velocity of 20 cm/s with a concordant increase in Hb of 1.7 g/dL at week 24 with voxelotor compared to baseline and a decrease in reticulocytes from 16.45% to 10.4% (Figure). TCD flow velocities in all other arterial segments showed an overall decline at week 24. All treatment-related adverse events were grade 1 or 2, and there were no treatment-related serious adverse events. Data for all adolescents treated with voxelotor 1500 mg/day for up to 24 weeks will be presented at the conference. Conclusions: Preliminary results indicate that voxelotor at 1500 mg/day was well tolerated. Data from 5 adolescents at 12 weeks show a marked improvement in Hb and reductions in clinical measures of hemolysis. Importantly, hematologic improvements are seen in adolescents already managed at the maximally tolerated dose of HU. Compared to previously reported data at 900 mg/day, this indicates a dose-dependent improvement in hemolytic anemia. One adolescent with conditional TCD, despite background HU, achieved normalized TCD flow velocity after voxelotor therapy. Overall, these results are consistent with in vivo inhibition of HbS polymerization by voxelotor and support the ongoing clinical evaluation of voxelotor as a potential disease-modifying therapy for adolescents with SCD. Disclosures Brown: Global Blood Therapeutics: Consultancy, Research Funding. Inati:Global Blood Therapeutics: Research Funding; Astra Zeneca: Research Funding; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees. Woods:Global Blood Therapeutics: Research Funding; Pfizer: Research Funding; Guidepoint: Honoraria; Putman: Honoraria; Children's Mercy Hospital: Employment, Membership on an entity's Board of Directors or advisory committees. Hsu:Global Blood Therapeutics: Research Funding; Astra Zeneca: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Ironwood: Research Funding; Emmi: Consultancy; Hilton Publishing: Consultancy; Gerson Lehman Group: Consultancy; Guidepoint: Consultancy. Piccone:Novartis: Consultancy. Fong:Global Blood Therapeutics: Employment. Dixon:Global Blood Therapeutics: Employment. Tonda:Global Blood Therapeutics: Employment. Washington:Global Blood Therapeutics: Employment. Lehrer-Graiwer:Global Blood Therapeutics: Employment.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4944-4944
Author(s):  
Maria Acevedo-Mendez ◽  
Anil Rao ◽  
Lewis L. Hsu

Abstract Introduction: Patients with sickle cell disease (SCD) are repeatedly exposed to diagnostic radiation. Radiographs, computed tomography (CT) and nuclear medicine scans are often ordered for suspected complications caused by sickle cell disease that exposes patients with SCD to ionizing or another form of radiation. A few studies of low-dose cumulative radiation exposure (in people without SCD) suggest that 30 to 100 mSv over 30 decades is associated with higher excess risk of leukemia. New epidemiologic data of low quality suggests that individuals with sickle cell disease (SCD) accumulate "driver mutations" for acute myelogenous leukemia (AML) about 20-30 years earlier than the general population, and have higher risk of AML. In a gene therapy protocol with a few dozen patients, 2 cases of AML have occurred in sickle cell disease and none in thalassemia. It has been reported that children with SCD are frequently exposed to ionizing radiation in the form of plain radiographs, fluoroscopy, computed tomography (CT) scans, bone scans, and other tests. Exposure to ionizing radiation during childhood carries a risk of developing cancer that is directly related to the total radiation dose.Epidemiological data has demonstrated an increase both in diagnostic radiation and in actual or predicted resultant cancer diagnosis. Children are particularly vulnerable to radiation-induced cancer because they are still actively growing and thus are at greater risk of acquiring an oncogenic mutation in an actively dividing cell. Hypothesis: Frequent diagnostic imaging for children and adults with SCD can have significant cumulative radiation exposure that could add excess risk of AML. Methods: The study design was a retrospective chart review. The sample was selected to be enriched for the most severely-affected children and adults in the Sickle Cell Center at UI Health, which provides medical care for over 700 patients with SCD. The subgroup on chronic erythrocytapheresis blood transfusionswere selected as a sample of severe of SCD who are more likely to be exposed to repeated diagnostic radiation. Many have had stroke, which often leads to repeated head CT and cerebral angiograms. Others had pulmonary embolism or acute chest syndrome, which can lead to chest CT angiograms. Other SCD complications with high risk of morbidity or morbidity lead to similar likelihood that patients on chronic exchange transfusion therapy would have histories of multiple imaging studies. Medical records were reviewed for the type and number of all radiographic tests, especially CT scans, during the 10-year period 2011-2020. A second observer confirmed a subset of charts. Standard references were used to estimate radiation exposure in mSv for each type of test. The sum of mSv for each individual was a rough estimate of cumulative radiation in 10 years. The IRB approved the protocol. Results: Chart review on 39 patients (ages 16 - 60y) identified 1,030 radiographic tests with a mean of 26.4 tests/patient. Seven patients had > 50 tests, and one patient had > 100 tests over a 10-year period. Thirty-three patients had at least one CT scan. Eighteen patients had at least 3 CT scans. Twenty patients had cumulative radiation exposure > 30 mSv over a 10-year period, 4 patients had > 100 mSv, and one patient had > 200 mSv. Plain radiographs comprised 71% (736) of the studies and relatively low dose radiation exposure. Discussion: This retrospective study estimated that diagnostic radiography exposed 20 of 39 patients with severe SCD to the range of 30 to 200 mSv over 10 years, mostly from numerous CT scans. This range of cumulative radiation exposure has mixed evidence about possible heightened risk of AML and other cancers. The study is limited by the small sample at a single institution and a heavy bias toward patients with stroke and chest complications, but this severely-affected subgroup comprises many of those eligible for transplant and gene therapy in SCD. Cumulative exposure to diagnostic radiation might be one mechanism for the unexplained patterns of AML in SCD after gene therapy that led to a pause in SCD gene therapy studies for a few months in 2021. Further studies are needed. Disclosures Hsu: Global Blood Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Aruvant: Consultancy, Membership on an entity's Board of Directors or advisory committees; Hoffman LaRoche: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Forma Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cyclerion: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Imara: Research Funding; Eli Lilly: Research Funding; Baxalta / Shire / Takeda: Research Funding.


Sign in / Sign up

Export Citation Format

Share Document