Squamous Cell Carcinoma as a Complication of Long-Term Hydroxyurea Treatment

Hydroxyurea therapy is commonly used in the treatment of patients suffering from myeloproliferative diseases, such as polycythemia vera. It is supported by evidence that this type of therapy can generate mild skin lesions like leg ulcers, erythema, and hyperpigmentation. There are also some studies that show an increased risk of development of nonmelanoma skin cancers. We report a 56-year-old man with a 13-year history of polycythemia vera, treated chronically with hydroxyurea. In April 2020, the patient presented a skin lesion on the forehead, skin horn on the left forearm, and hyperkeratosis on the rims of both ears. In the patient’s history, in October 2019, complete excision of the skin lesion in the central area of the forehead was performed. After 4 months, a new skin lesion appeared at the same area of the forehead, which in May 2020 after resection in the histopathological examination was diagnosed as recurrence of squamous cell carcinoma. The aim of the case is to draw the clinicians’ attention to the increased risk of squamous cell carcinoma and basal cell carcinoma in patients treated with hydroxyurea. Increased vigilance would make it possible to recognize them earlier, and thus potentially reduce the undesirable effects associated with the delayed radical treatment of these skin cancers. Randomized clinical trials assessing the potential benefits of oral retinoids for chemoprevention of nonmelanoma skin cancers in the hydroxyurea-treated population should also be considered.

Effect of Hydroxyurea Therapy on the Incidence of Infections in Ugandan Children with Sickle Cell Anaemia

Hydroxyurea is efficacious against sickle cell anaemia (SCA)-related complications in African children. Prior studies demonstrated conflicting results on the effect of hydroxyurea on risk of infection, the most common cause of morbidity and mortality in African children with SCA. We evaluated the incidence of infections before and after starting hydroxyurea in 117 children aged 1-5 years with SCA enrolled in the Zinc for Infection Prevention in Sickle cell anaemia (ZIPS) clinical trial that received zinc or placebo treatment for one year (Clinicaltrials.gov, NCT03528434). Children were enrolled between March 2018 and November 2019 and initiated on hydroxyurea (20 mg/kg/day) if they met Uganda SCA guideline criteria for hydroxyurea treatment at any time during the study. We compared the incidence of infections before and after hydroxyurea therapy, adjusting for zinc treatment. Overall, the mean duration on hydroxyurea was 223.8 (85.2) person days. The mean(SD) incidence of any severe/invasive infections (infections meeting strict clinical and laboratory or radiological diagnostic criteria) was 6.2(9.0) vs. 1.9(2.3) infections per child per year before and after hydroxyurea (incidence rate ratio [IRR]: 0.40, 95%CI: 0.29-0.54, p<0.001), including a decrease in the incidence of bacteremia [IRR: 0.05] malaria, [IRR 0.28], cellulitis [IRR: 0.24], gastroenteritis [IRR: 0.41], pharyngitis [IRR: 0.59] and sinusitis [IRR: 0.38] (all p<0.05). Similarly, the incidence of clinically defined infections (infections meeting clinical but not laboratory/radiological criteria) decreased after hydroxyurea, (IRR: 0.49, 0.41-0.59), influenced primarily by large reductions in the incidence of lower and upper respiratory tract infections (p<0.001 for both). As expected, hydroxyurea treatment was also associated with a decrease in complications of SCA, including vaso-occlusive crises, hospitalizations and transfusions (all p<0.001). There was no interaction between zinc and hydroxyurea therapy on risk of infection and SCA-related complications. In Ugandan children with SCA, hydroxyurea therapy not only decreases the incidence of SCA-related complications, but also substantially reduces the incidence of infections. Research to understand the underlying mechanisms of protection from hydroxyurea against infection and exploration of its potential use for infection prevention is warranted. Disclosures Ware: Bristol Myers Squibb: Research Funding; Addmedica: Research Funding; Hemex Health: Research Funding; Nova Laboratories: Research Funding; Novartis: Other: DSMB Chair; Editas: Other: DSMB Chair.

Combined +58 and +55 BCL11A enhancer Editing Yields Exceptional Efficiency, Specificity and HbF Induction in Human and NHP Preclinical Models

Targeting the BCL11A erythroid enhancer by gene editing is a promising approach to fetal hemoglobin induction for beta-hemoglobinopathies. HbF levels vary widely among individuals, suggesting potential heterogeneity in HbF responses after therapeutic intervention. We hypothesize that maximizing both gene edit frequency and HbF induction potential could promote consistently favorable clinical outcomes. Here we compared CRISPR-Cas9 endonuclease editing of the BCL11A +58 enhancer with alternative gene modification approaches, including +55 erythroid enhancer editing alone or in combination with the +58 enhancer, as well as editing targeting the HBG1/2 promoter -115 BCL11A binding site and transduction by an shRNA knocking down the BCL11A transcript in erythroid precursors. We found that combined targeting of the BCL11A +58 and +55 enhancers with 3xNLS-SpCas9 and two sgRNAs resulted in the most potent HbF induction (52.4%±6.3%) of tested approaches (BCL11A +58 editing alone, 29.1%±3.9%; BCL11A +55 editing alone, 34.8±5.1%; HBG1/2 promoter editing, 34.1% ±5.4%; shmiR-BCL11A, 32.2%±4.4%; mock, 7.6%±3.4%). Based on assays in bulk and single cell derived erythroid cultures and xenografted immunodeficient mice, we found that disruption of core half E-box/GATA motifs at both the +58 and +55 enhancers was associated with greatest HbF induction, whether by small indels, interstitial 3.1 kb deletion, or 3.1 kb inversion. Rare gene edited clones with alleles that only partially disrupted these motifs were associated with intermediate HbF induction phenotypes. Combined editing of BCL11A +58 and +55 enhancers was compatible with HSC self-renewal in primary and secondary xenotransplant, with intact lymphoid, myeloid and erythroid repopulation. We conducted gene-edited cell product manufacturing process development and developed conditions using a MaxCyte electroporation instrument achieving mean 97.3±1.8% gene edits and 88.9%±6.4% viability 24 hours after electroporation in 3 engineering runs at clinical scale. We obtained similar results at small-scale with plerixafor-mobilized HSPCs from sickle cell disease (SCD) donors or G-CSF mobilized PBMCs from transfusion-dependent beta-thalassemia (TDT) donors, including 94.2%±4.4%, 99.5%±0.3% and 91.8%±6.3% of gene edits in engrafting cells from NBSGW 16 week mouse bone marrow of healthy, SCD and TDT donors respectively. Off-target analyses by pooled amplicon sequencing of 601 candidate off-target sites for the +58 and +55 targeting sgRNAs, nominated by a range of computational (CRISPRme) and experimental (GUIDE-seq and ONE-seq) methods, did not identify reference genome off-target edits at a sensitivity of 0.1% allele frequency. We evaluated +58/+55 enhancer combined targeting in nonhuman primates by performing ribonucleoprotein (RNP) electroporation in rhesus macaque mobilized peripheral blood CD34+ HSPCs with autologous re-infusion following busulfan myeloablation. We observed highly efficient gene edit frequency (85.2%, 88.8% and 84.9%) and durable HbF induction (26.4%, 57.5%, and 45.9% F-cells and 12.7%, 41.9%, and 28% gamma-globin) in the peripheral blood in 3 animals at most recent recorded time point post infusion (127, 78, and 54 weeks respectively). Single colony analyses and bulk ddPCR and unidirectional sequencing demonstrated that the long-term engrafting cells displayed a similar distribution of indels, 3.1 kb deletions, and 3.1 kb inversions as the input cell products. Erythroid stress due to hydroxyurea treatment, with or without phlebotomy, was associated with substantially augmented HbF responses (to 75.9%, 88.2%, and 57.8% F-cells and 47.9%, 68%, and 35.7% gamma-globin). No hematologic or other toxicities attributable to gene editing were observed. Together these results suggest that combined BCL11A +58 and +55 erythroid enhancer editing produces highly efficient on-target allelic disruption, erythroid-specific BCL11A downregulation, heightened HbF induction capacity compared to alternative approaches, preserved long-term multilineage engraftment potential by both human xenotransplant and rhesus autotransplant assays, and absence of evident genotoxicity, under clinically relevant SpCas9 RNP electroporation conditions. Disclosures No relevant conflicts of interest to declare.

L-Glutamine and Crizanlizumab for Adults with Sickle Cell Disease (SCD) in Qatar: A Cost Effectiveness Analysis

Background :Sickle cell disease (SCD) is a hereditary disease that is caused by autosomal recessive gene fault in the beta (β) allele of the hemoglobin (Hb) gene. As a result, sickled cells are characterized by easy and abnormal hemolysis with resultant varying degrees of anemia. Globally, the incidence of SCD is estimated to reach 400,000 persons per year, and in the United States alone, for example, the prevalence estimation is approximately 100,000 patients. Possible clinical presentations of SCD may come from different pathophysiologic mechanisms: the disfiguration of the RBC with subsequent loss of function can lead to vascular occlusion and a short lifetime of these RBCs that leads to hemolysis. The most severe and serious manifestation of SCD is the recurrent acute pain, or better known as vaso-occlusive crisis (VOC). Additionally, other clinical manifestations that SCD patients may show are acute complications such as acute chest syndrome (ACS), recurrent infections, kidney necrosis, and stroke. Such complications may affect multiple organs and can result in early death. Acute pain crisis is another common complication of SCD and is usually managed with pain medications, especially opioids, This is the first study to address two of novel therapies in patients with SCD in the Middle East. Our study was comprehensive in terms of outcome mostly encountered by SCD patients which is VOC and inclusivity of interventions mostly used for its management and was focused on the target population of in one of areas of high prevalence of SCD in the world. Our analysis tracked the CHEERS guidelines and checklist for reporting. To be also complete, we used only RCT evidence in our analysis. Additionally, in considering VOC, we ensured only studies with a definition compatible with that of the principal Crizanlizumab study were analyzed. Objectives: Treatment options for preventing vaso-occlusive crises (VOC) among sickle cell disease (SCD) patients are on the rise, especially if hydroxyurea treatment has failed. This economic analysis is conducted to assess the comparative clinical effectiveness, safety and acquisition cost of L-glutamine and Crizanlizumab for older adolescent and adults (≥16 years old) SCD in Qatar, with an emphasis on treatment costs and acute pain crises. Methods: We conduct a decision tree model, where we compare the clinical and economic outcomes of two novel FDA-approved medications which are available in Qatar; L-glutamine and Crizanlizumab over a time horizon of one year in a hypothetical cohort of adult SCD patients from a Qatar healthcare perspective. The main outcome is incremental cost per SCD-related acute pain crises averted. Model clinical parameters were derived from individual drug randomized trials, published literature, whereas cost parameters from Qatar healthcare payer system. A sensitivity analysis was carried out, and the study results were robust around model inputs. Costs were converted to 2020 US dollars. Results: Study results showed that both treatment modalities' costs were the main driver of this analysis, with average annual cost of the treatments per patient being $189,014 for Crizanlizumab (5mg/Kg), $143,798 Crizanlizumab (2.5mg/Kg) and $74,323 for L-glutamine. The probability of no first time SCD-related VOC averted were 0.001/year for Glutamine, 0.26/year for Crizanlizumab (5mg/Kg) and 0.34/year for Crizanlizumab (2.5mg/Kg). Lower dose Crizanlizumab (2.5mg/Kg) dominated the higher one (5mg/Kg). The ICER of Crizanlizumab (2.5mg/Kg), when compared to L-Glutamine was $81,265 per SCD-related VOC averted. When comparing Crizanlizumab (5mg/Kg) and L-Glutamine, Crizanlizumab (5mg/Kg) showed higher efficacy, yet the Crizanlizumab ICER was at $459,620 than L-glutamine. Conclusions: Crizanlizumab (2.5mg/Kg) may be cost-effective interventions yet it is not the approved dose for preventing VOC in adolescents and adults with sickle cell disease. Crizanlizumab (5mg/Kg) was more cost effective than the approved L-glutamine per SCD vaso-occlusive crisis prevented. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

First Year Comparison of Sickle Cell Pediatric Cohorts from Haiti and Miami (CSHSCD Multicenter Study): Baseline Data

Background: The NIH-sponsored observational study "Comparative Study of Haiti and Miami Cohorts of Sickle Cell Disease CSHSCD" (R01HL149121) coordinates the follow up of children with sickle cell disease (SCD) in Haiti and compares it to a Miami cohort of children of either Haitian or African American ethnicity for the purpose of assessing barriers through questionnaires and examining differences in the care received in their respective environments. Methods: Children less than 6 years of age with SCD are eligible for enrollment in five participating sites: University of Miami (UM, Miami, Florida), Hôpital Saint Damien (HSD, Tabarre, Haiti), Hôpital de l' Université d'Etat d'Haïti (HUEH, Port-au-Prince, Haiti), Hôpital Universitaire Justinien (HUJ, Cap Haitien, Haiti), and Hôpital Sacré Coeur (HSC, Milot, Haiti). Medians and interquartile ranges or percentages were compared at baseline regarding demographics, clinical and growth parameters, laboratory tests, and the children's hydroxyurea (HU) utilization during the first year of enrollment (May 25, 2020-May 24,2021). A Likert-scale barrier questionnaire was distributed at baseline to assess differences in healthcare access. A P value <0.05 was considered statistically significant to establish differences. Results: 130 children were enrolled during the reported period. Significant differences were observed in age, weight percentiles, hemoglobin levels, pain rates, HU treatment, and pneumococcal vaccination. Penicillin prophylaxis was always given by oral route in Miami, but only 39.8% times in Haiti, with 58% of children receiving prophylaxis by intramuscular injection every month and 2.2% (N=2 children) with either unknown or not receiving prophylaxis. Previous medication outsourcing accounted for the oral tablet form in Haiti. Parents in Haiti had more barriers regarding not able to afford treatment (21.5% compared to 8.1% in Miami) and had similar responses regarding not able to afford coming to clinic (21.5% vs. 18.9%). Parents in Miami expressed living far away from clinic (70.2% compared to 25.8% in Haiti), but had more help from other family members (78.4% vs. 33.3%). Interestingly, parents in Miami did not know sometimes what to do when the child was sick (40% respondents vs. 11% in Haiti). There were no major differences between the responses from the African Americans and Haitians living in Miami, except for not knowing sometimes what to do when child is sick (African-Americans having less doubts than Haitians; 25% vs. 52.6%). In short-term follow up, no enrolled children died, although two eligible children in Haiti died before enrollment. One child developed COVID-19 in Miami with only mild symptoms, which resolved. Conclusion: At entry children in Haiti are older, weigh less, are more anemic, have more pain episodes, and fewer receive hydroxyurea treatment. Under-vaccination with pneumococcal 13-valent conjugate (Prevnar-13) is notable in Haiti. There were significant differences detected on the barrier questionnaire among respondents in both countries. Acknowledgment: We acknowledge NHLBI for supporting this work. Figure 1 Figure 1. Disclosures Alvarez: GBT: Membership on an entity's Board of Directors or advisory committees; Forma Therapeutics: Membership on an entity's Board of Directors or advisory committees.

Hydroxyurea Reduces the Transfusion Burden in Children with Sickle Cell Anemia: The Reach Experience

Introduction: Many children with sickle cell anemia (SCA) require blood transfusions, which carry risks and utilize a scarce resource globally, particularly in Africa. Realizing Effectiveness Across Continents with Hydroxyurea (REACH, NCT01966731) has documented the safety, feasibility, and benefits of hydroxyurea for children with SCA living in sub-Saharan Africa. In REACH, hydroxyurea escalated to maximum tolerated dose (MTD) significantly decreased vaso-occlusive events, malaria, and death; transfusions were decreased by ~70% over 30 months of treatment when compared to the 2-month screening period. Characterizing how hydroxyurea reduces transfusion needs in REACH could contribute to improved clinical understanding and lead to better outcomes, a decreased transfusion burden, and preservation of the blood supply in these limited-resource settings. Methods: Transfusions were recorded prospectively in the REACH REDCap electronic database. Using time-varying predictors and landmark analysis, transfusions during screening and treatment were analyzed by clinical site, calendar month, age, gender, splenomegaly, hydroxyurea dose, MTD status, baseline and latest laboratory values (Hemoglobin, MCV, HbF, absolute neutrophil count, and platelets, all measured at least 30 days prior to the transfusion), alpha thalassemia trait, and G6PD deficiency. Incidence rate ratios (IRR) were calculated for treatment periods compared to screening. Univariate relationships were assessed using the Anderson-Gill model, plus multiple regression to estimate Hazard Ratios (HR) with 95% confidence intervals (CI's). Results: A total of 635 children with SCA enrolled in REACH, and 606 started hydroxyurea treatment. During screening, 48 transfusions were given to 43 children, and during the treatment phase 405 transfusions were administered to 214 children over an average treatment time of 5.2 ± 1.3 years. The transfusion rate was 43.3 per 100 patient-years during screening, which decreased to 22.0 per 100 patient-years during the initial fixed dose treatment period (IRR = 0.50; 95%CI = 0.35-0.74, p<0.001 compared to screening) and then decreased further to 12.1 per 100 patient-years during the dose escalation period (IRR = 0.28; 95%CI = 0.21-0.39, p<0.001 compared to screening; IRR = 0.54; 95%CI = 0.43-0.73, p<0.001 compared to fixed-dose). For every 100 children treated for a year with hydroxyurea during dose escalation, there were 31.4 fewer transfusions compared to the untreated screening period. Comparison of the indications for transfusion between the screening and treatment periods revealed transfusions administered for anemia decreased from a rate of 26.1 to 5.1 per 100 patient-years (p<0.001), while transfusions for malaria trended toward a decrease from 7.2 to 3.8 per 100 patient-years (p=0.08). Lower transfusion rates on hydroxyurea were associated with higher hemoglobin concentration (HR = 0.72 per 1g/dL increase; 95%CI = 0.65-0.78, p <0.0001) and higher HbF levels (HR = 0.80 per 10% increase, 95%CI = 0.69-0.92, p=0.0071). Those with palpable splenomegaly had higher transfusion rates (HR = 1.58, 95%CI = 1.22-2.03, p=0.0094). Age, gender, alpha thalassemia trait, G6PD deficiency, and neutrophil count were not associated with differences in transfusion rates. Conclusion: Hydroxyurea significantly reduces blood transfusion administration in children with SCA in sub-Saharan Africa, especially when escalated to MTD. Transfusions for the sole indication of anemia decreased significantly on hydroxyurea treatment, likely due to higher treatment-associated hemoglobin levels and decreased hemolysis, and transfusions for malaria also trended toward a decrease. Splenomegaly remains a risk factor for transfusions despite hydroxyurea treatment. Overall, increased access to and implementation of hydroxyurea treatment for children with SCA across sub-Saharan Africa may not only improve individual patient outcomes through reduction in anemia, transfusion burden, and transfusion-associated complications including infections, but may also to help preserve the scarce blood supply for the benefit of the larger population. Disclosures Aygun: Global Blood Therapeutics: Consultancy; Patient Centered Outcomes Research Institute: Research Funding; National Heart, Lung, Blood Institute: Research Funding; National Institute of Nursing Research: Research Funding; bluebird bio, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding. Stuber: ASH Research Collaborative: Consultancy. Ware: Bristol Myers Squibb: Research Funding; Addmedica: Research Funding; Hemex Health: Research Funding; Nova Laboratories: Research Funding; Novartis: Other: DSMB Chair; Editas: Other: DSMB Chair.

Impact of a grant program to spur advances in sickle cell disease research

More than 20 years ago, clinical trials and federal grant support for sickle cell disease (SCD) research were not on par with support for other genetic diseases. Faced with the opportunity to spur research and advance treatments for SCD, and at the recommendation of advisors, the Doris Duke Charitable Foundation (DDCF) offered an SCD research funding opportunity starting in 2009 through its Innovations in Clinical Research Awards (ICRA) program. Twenty-eight new grants of $450 000 for direct costs over 3 years and 7 renewals were awarded, for a total investment of $17 million. Only about half the research teams garnered follow-on funding directly related to their ICRA projects, but the financial return on the research investment was substantial (∼4 times the original $17 million or 300%). All but 1 of the ICRA investigative teams published original research reports that acknowledged DDCF as a source of funding; the median number of publications per team was 3. Major innovations in the diagnosis and treatment of SCD included but were not limited to a demonstration that genetic modification of BCL11A enhancer is a potentially important treatment modality, establishment that plerixafor mobilization is safe and effective for those with SCD, development and validation of a new diagnostic called SCD BioChip, and evidence that hydroxyurea treatment is safe and efficacious in African children. These outcomes show that relatively small research grants can have a substantial return on investment and result in significant advances for a disease such as SCD.

Retinal microvascular analysis using Fundus Fluorescein Angiography in Egyptian sickle cell disease patients

Background Sickle cell disease can affect retina of eye via vaso-occulsive changes that occur in micro-vessels of retina which could be analysed by using Fundus Fluorescein Angiography. Aim To analyze macular microvascular alternation in patients with SCD by Fundus Fluorescein Angiography (FFA) and to assess the role of potentially contributory Clinico-pathological factors including Trans-Cranial Doppler, genotypes, hydroxyurea, transfusion therapy and finally iron overload state on the development of macular alterations. Method This was across-sectional study which included 30 Sickle cell disease patients randomly recruited from the Paediatric Haematology clinic, children Hospital, Ain Shams University, Cairo, Egypt. Complete blood count (CBC), Trans-Cranial Doppler (TCD) and Fundus Fluorescein Angiography. Results In our study, there were 30 patients with mean age (14.1± 4.02), 5 patients had abnormal/conditional Trans-Cranial, 15 patients had Vaso-occlusive crises, 11 patients were on regular simple blood transfusion; all 30 studied sickle cell disease patients had normal Fundus Fluorescein Angiography and eye examination and only one patient hadabnormal visual acuity;A 29 years oldgirl who had five attacks of cerebral strokes last year, on regular simple blood transfusion and Hydroxyurea treatment with abnormal TCD and recurrent Vaso-occlusive crises in last two years, Although her vision is hand movement yet Fundus Fluorescein Angiography was normal. Conclusion we didn’t find any Retinal microvascular alternation in our studied SCD patients using Fundus Fluorescein Angiography, we related our results to the fact that our studied SCD patients were young and all our studied patients were on hydroxyurea therapy with fair compliance, further studies using large sample size are warranted in order to illustrate the utility of Fundus Fluorescein Angiography (FFA) as a tool for better detection of sickle retinopathy.