Hydroxyurea Research Articles

S131: REGIONAL ASSESSMENT OF THE EXPERIENCES OF HEALTHCARE PROFESSIONALS (HCPS) TREATING PATIENTS WITH SICKLE CELL DISEASE (SCD): THE INTERNATIONAL SICKLE CELL WORLD ASSESSMENT SURVEY (SWAY)

Background: SCD has a high clinical burden, results in poor quality of life (QoL) and reduces life expectancy in many patients (pts). To improve treatment/management, it is important to gain a deeper understanding of pt and HCP experiences. Aims: SWAY was a cross-sectional survey that assessed pt and HCP experiences of SCD. Here we focus on the experiences of HCPs from various regions on SCD symptoms and complications, impact of SCD on QoL, treatment goals and treatment satisfaction. Methods: SWAY was an international cross-sectional survey developed by international expert physicians, pt advocates and Novartis to assess pt and HCP experiences of SCD. Here we focus on the experiences of 365 HCPs who manage ≥10 SCD pts (≥5 in Canada, ≥2 in the Netherlands) and who completed the survey in April–October 2019. Responses to questions on how much SCD impacts pts’ emotional wellbeing, QoL and daily life, as well as HCP treatment satisfaction, were ranked on a Likert scale (1–7: 1=not at all/strongly dissatisfied, 7=a great deal/strongly satisfied; 5–7 indicated high impact/satisfaction). Results: HCPs in all six regions recognized the prevalence of acute and chronic pain (although less frequently in Africa vs other regions; Table). Acute chest syndrome and joint issues were among the five most common complications reported by HCPs in all regions. Globally, HCPs noted the high impact of SCD on emotional wellbeing (71–97%) and of symptoms/complications on QoL (79–100%). Fewer HCPs in the Middle East (ME) reported a high impact of SCD on physical and sexual activity compared with other regions (Figure). Around 40% of HCPs in the ME and Asia thought that SCD has a high impact on daily activities, compared with 77–90% in other regions. In Asia, fewer HCPs reported that SCD has a high impact on pts’ education (48%) and ability to maintain a job (43%) compared with other regions (69–90% and 56–90%, respectively). Hydroxyurea (HU) was among the three most common therapies ever initiated and the therapy most likely to be initiated in any age group by HCPs in all regions except Africa (Table). Improving pts’ QoL was the top treatment goal for HCPs across all regions (51–84%). Fewer HCPs in North America (32%), South America (27%) and Europe (46%) were highly satisfied with current SCD treatments compared with other regions (62–72%); the main reason for dissatisfaction was limited treatment options in all regions except Asia. Summary: The most frequent SCD symptoms/complications that HCPs reported were similar across all regions. However, regional differences in HCP experiences of how SCD impacts pts’ daily life exist (eg fewer HCPs reported a high impact on physical/sexual activity in the ME, on daily activities in the ME/Asia, and on education/work in Asia, vs other regions), which may be explained by cultural variations. HU was one of the three most common prior treatments in all regions except Africa, which may indicate an educational knowledge gap, particularly as the HCPs from Africa who completed the survey were primarily non-specialists. This could also reflect poor access to HU and/or its high cost in Africa. HCPs in most regions were dissatisfied with SCD treatments because of limited options, indicating a global unmet need for additional treatment choices. Improving QoL was the main treatment goal for HCPs in all regions, which may be indicative of a high negative impact of SCD on pt QoL and the ongoing need to address this.

Avaliação de prescrições pediátricas de hidroxiureia para pacientes com doença falciforme

Hydroxyurea (HU) was one of the main advances in the treatment of sickle cell disease. The use of the drug in children in Brazil is still off-label and is only available in solid pharmaceutical form. The objective of the present study is to evaluate the strategies for adapting the solid dosage form for use in children with sickle cell disease. This is a descriptive study, with the analysis of pediatric HU prescriptions and the application of questionnaires to those responsible in the period from January to March 2018. 43 prescriptions were analyzed, and two forms of adaptation were identified, 1) conventional dilution: dilution of the drug in a pre-prescribed quantity - determined amount of water, followed by administration of part of the solution obtained (22) (51%), and 2) use of the holiday or intermittent dose recommendation (21) (49%). All patients using the conventional dilution strategy discarded the remainder of the drug from the domestic sewage system. In addition, incorrect administration of the drug was identified in one patient. The lack of an appropriate pharmaceutical form for the pediatric population can lead to risks of incorrect administration and unnecessary expenses with drug disposal, in addition to improper disposal that compromises environmental factors. This study reinforces the need to develop pharmaceutical forms that are more suitable for children.

Synchronization of Leishmania amazonensis Cell Cycle Using Hydroxyurea.

Leishmania spp. comprises a group of protozoan parasites that affect millions of people around the world. Understanding the main cell cycle-dependent events could provide an important route for developing specific therapies since some factors involved in cell cycle control may have low similarity relative to their homologs in mammals. Furthermore, accurate cell cycle-dependent analyses often require many cells, which can be achieved through cell cycle synchronization. Here, we described a useful method to synchronize procyclic promastigote forms of Leishmania amazonensis using hydroxyurea (HU) and the analysis of its DNA content profile. This approach can be extended to other trypanosomatids, such as Trypanosoma cruzi or Trypanosoma brucei, and provides an effective method for arresting more than 80% of cells at the G1/S phase transition.

Pediatric Patients With Sickle Cell Disease at a Public Hospital: Nutrition, Compliance and Early Experience With L-Glutamine Therapy.

Hydration and hydroxyurea (HU) can modify sickle cell disease (SCD) severity. Optimal nutrition and L-glutamine (Gln) may provide further amelioration. Reviews of medical records and nutrition surveys were used to investigate severity of pediatric patients with SCD in relation to nutrition, growth, hematologic parameters, and diseasemodifying agents. Among 25 females and 25 males (9.1±7 years), beta-globin genotypes were: HbSS/Sβ°, 60%; HbSC, 32%; HbSβ+, 8%. The mean number of annual pain crises (APC) was 0.97±1.1. APCs increased ≥2-fold as HbF dropped to <10% with age. Proper hydration and nutrition correlated with younger ages and fewer APCs. Height and weight Z-scores were ≤-1SD in 20% of 35 surveyed patients (12±7.8 years), who had more APCs (2.5±2.5 vs. 1±1.3, p=0.03). Prealbumin levels were overall low. Twenty-two of 28 patients on HU reported ≥90% adherence - with higher mean corpuscular volume (92±9.6 vs. 74±10 f/l, p<0.01). Seventy percent of Gln prescriptions were filled. Compliance over 23 months was ≥70% in 12 patients, including 2 on chronic transfusion. Of 10 evaluable patients, 6 (8.8±2.2 years) had fewer APCs with Gln (mean 0.2 vs. 0.9, p=0.016), with increasing prealbumin levels (14.1 to 15.8 mg/dl, p=0.1). Younger, and well-nourished, well-hydrated patients have a milder clinic course. Disease severity was the worse in undernourished teenagers with suboptimal compliance. L-Glutamine with prealbumin monitoring should be considered for further evaluation in pediatric SCD.

Evaluation of pediatric hydroxyurea prescriptions for patients with sickle cell disease

Hydroxyurea (HU) was one of the main advances in the treatment of sickle cell disease. The use of the drug in children in Brazil is still off-label and is only available in solid pharmaceutical form. The objective of the present study is to evaluate the strategies for adapting the solid dosage form for use in children with sickle cell disease. This is a descriptive study, with the analysis of pediatric HU prescriptions and the application of questionnaires to those responsible in the period from January to March 2018. 43 prescriptions were analyzed, and two forms of adaptation were identified, 1) conventional dilution: dilution of the drug in a pre-prescribed quantity - determined amount of water, followed by administration of part of the solution obtained (22) (51%), and 2) use of the holiday or intermittent dose recommendation (21) (49%). All patients using the conventional dilution strategy discarded the remainder of the drug from the domestic sewage system. In addition, incorrect administration of the drug was identified in one patient. The lack of an appropriate pharmaceutical form for the pediatric population can lead to risks of incorrect administration and unnecessary expenses with drug disposal, in addition to improper disposal that compromises environmental factors. This study reinforces the need to develop pharmaceutical forms that are more suitable for children.

Effect of Counselling on Compliance of Hydroxyurea Therapy and Frequency of Hospital Admissions among Patients with Sickle Cell Disease- A Longitudinal Study

Introduction: Sickle Cell Disease (SCD) is an autosomal recessive multisystem disorder, characterised by anaemia, recurrent episodes of pain and chronic organ damage. Hydroxyurea (HU), a disease modifying agent with proven efficacy in reducing painful episodes in SCD patients thereby improving quality of life. Compliance to hydroxyurea therapy is a liming factor in management of SCD. Aim: To compare adherence to HU therapy and frequency of hospital admissions before and after counselling. Materials And Methods: This longitudinal study was conducted in Department of Paediatrics at Gandhi Medical College and associated Hamidia Hospital Bhopal, Madhya Pradesh, India, from 1st January 2020 to 30th June 2021. Patients with SCD, between the age group of 1-14 years, in a study period were recruited for the study. After enrolment, data regarding HU therapy and admissions in the previous one year was recorded for each registered patient. This was followed by detailed counselling sessions, which were repeated at 3 monthly intervals for a period of 1 year. Post-counselling data collection was done to evaluate the response. The effect of counselling was assessed using Chi-square test (for categorical variables) and Analysis of Variance (ANOVA) or paired t-test (for continuous variables). A p-value&lt;0.05 was considered statistically significant. Results: Initially, a total of 42 patients were registered, out of which only 31 patients could be followed-up till the last counselling. Mean age of the patients was 7.8±3.5 years, and 20 (64.5%) cases were males. As per history and previous year data total of 26 (83%) patients were already on HU therapy. Frequency of crises, hospital admissions, school absenteeism, and blood transfusion reduced significantly post counselling. The common factor associated with non adherence to therapy were non availability of drugs 21 (67.7%), followed by improper follow-up 20 (64.5%) and unawareness 17 (54.8%). Financial problems, non-palatability and distance from the hospital were other associated factors in 11 (35.5%), 4 (12.9%) and 2 (6.5%) cases, respectively. Conclusion: With counselling, better drug compliance to HU therapy was observed. This is expected to help in achieving better disease control in terms of reduced need for blood transfusion, hospital admissions as well as school absenteeism.

Neurocognitive functioning in preschool children with sickle cell disease.

Children with sickle cell disease (SCD) experience neurodevelopmental delays; however, there is limited research with preschool-age children. This study examined neurocognitive risk and protective factors in preschoolers with SCD. Sixty-two patients with SCD (60% HbSS/HbSβ0 -thalassemia; 40% HbSC/HbSβ+ -thalassemia) between the ages of 3 and 6years (mean = 4.77years) received a neuropsychological evaluation as routine systematic surveillance. Patients were not selected for disease severity, prior central nervous system findings, or existing cognitive concerns. Thirty-four patients (82% HbSS/HbSβ0 -thalassemia) were prescribed hydroxyurea (HU) at the time of their neuropsychological evaluation. On average, these patients had been prescribed HU at 2.15 (standard deviation = 1.45)years of age. The average dose was 28.8mg/kg/day. Besides genotype, there were no group differences in medical or demographic factors based on HU treatment status. Patients with HbSS/HbSβ0 -thalassemia scored below normative expectations on measures of intelligence, verbal comprehension, and school readiness (false discovery rate-adjusted p-value [pFDR ]<.05). Age, sickle genotype, and HU treatment exposure were not associated with measured neurocognitive outcomes (pFDR >.05). Greater social vulnerability at the community level was associated with poorer performance on measures of intellectual functioning, verbal comprehension, visuomotor control, and school readiness, as well as parent report of executive dysfunction (pFDR <.05). Greater household socioeconomic status was positively associated with academic readiness. Preschoolers with severe SCD (HbSS/HbSβ0 -thalassemia) perform below age expectations on measures of intelligence and academic readiness. Sociodemographic factors were stronger drivers of neurocognitive performance than disease severity or disease-modifying treatment. Neurodevelopmental interventions targeting the home and broader community environment are needed.

Spirometric Changes After Initiation of Hydroxyurea in Children With Sickle Cell Anemia.

Individuals with sickle cell disease (SCD) develop a decline in lung function over time. Hydroxyurea (HU) is the most common disease-modifying therapy used in SCD. We hypothesized that children with SCD treated with HU will have a slower decline in pulmonary function. We performed a retrospective chart review of children with HbSS and HbS-beta zero thalassemia referred to pulmonology for respiratory symptoms. We compared the spirometry results at 2 time points between children on HU (HU group) and not on HU (control group). For the HU group, these endpoints were evaluated before and after being on HU. The mean time interval between 2 spirometry studies was not significantly different between the groups (2.6±1.5 y for HU group vs. 3.0±1.8 y for the control group; P =0.33). The mean age of patients in the HU group was 9.8±3.8 years (55% male) and 10.7±4.9 years (50% male) in the control group. The spirometry data was compared within and between the groups using t test. There was a significant increase in forced vital capacity in HU group during follow-up, while children in the control group showed a decline (7.2±17.1 vs. -3.4±18.2; P <0.01). Our study suggests that HU therapy may help preserve lung function over time in children with SCD.

The MDM2 antagonist idasanutlin in patients with polycythemia vera: results from a single-arm phase 2 study

Idasanutlin, an MDM2 antagonist, showed clinical activity and a rapid reduction in JAK2 V617F allele burden in patients with polycythemia vera (PV) in a phase 1 study. This open-label phase 2 study evaluated idasanutlin in patients with hydroxyurea (HU)-resistant/-intolerant PV, per the European LeukemiaNet criteria, and phlebotomy dependence; prior ruxolitinib exposure was permitted. Idasanutlin was administered once daily on days 1 through 5 of each 28-day cycle. The primary end point was composite response (hematocrit control and spleen volume reduction > 35%) in patients with splenomegaly and hematocrit control in patients without splenomegaly at week 32. Key secondary end points included safety, complete hematologic response (CHR), patient-reported outcomes, and molecular responses. All patients (n = 27) received idasanutlin; 16 had response assessment (week 32). Among responders with baseline splenomegaly (n = 13), 9 (69%) attained any spleen volume reduction, and 1 achieved composite response. Nine patients (56%) achieved hematocrit control, and 8 patients (50%) achieved CHR. Overall, 43% of evaluable patients (6/14) showed a ≥50% reduction in the Myeloproliferative Neoplasm Symptom Assessment Form Total Symptom Score (week 32). Nausea (93%), diarrhea (78%), and vomiting (41%) were the most common adverse events, with grade ≥ 3 nausea or vomiting experienced by 3 patients (11%) and 1 patient (4%), respectively. Reduced JAK2 V617F allele burden occurred early (after 3 cycles), with a median reduction of 76%, and was associated with achieving CHR and hematocrit control. Overall, the idasanutlin dosing regimen showed clinical activity and rapidly reduced JAK2 allele burden in patients with HU-resistant/- intolerant PV but was associated with low-grade gastrointestinal toxicity, leading to poor long-term tolerability. This trial was registered at www.clinincaltrials.gov as #NCT03287245.

Response to Hydroxyurea in a Patient With Sickle Cell Hepatopathy: A Case Report

Sickle cell hepatopathy is an underreported entity lacking clear management guidelines. This case highlights the potential role of hydroxyurea (HU) in improving the hepatic dysfunction seen among patients with sickle cell disease (SCD). We herein present the clinical course of a patient prior to and after the initiation of hydroxyurea with an emphasis on long-term outcomes and the patterns of liver injury over a 15-year time course.

Impact of hydroxyurea on lymphocyte subsets in children with sickle cell anemia.

Hydroxyurea (HU) has beneficial effects in the management of sickle cell anemia (SCA), but there is a paucity of data on the effect of HU on immune cells in SCA. Herein we aimed to evaluate the effect of HU on immune profiles of Egyptian children with SCA. This was a controlled prospective cohort study conducted in 30 children with SCA and 30 healthy age-matched controls. Flow cytometry was used to evaluate lymphocyte profiles, including CD8+ T, CD19+ B, CD3+, CD4+, natural killer (NK), NK T, T helper 1 (Th1), Th2, T cytotoxic (Tc1), and Tc2 cells, prior to and after 1 year of treatment with HU. HU treatment led to significant increases in hemoglobin (Hb), red blood cell, and hematocrit counts and a significant decrease in the percentage of sickle Hb, with subsequent improvement in SCA complications. Compared with baseline values, CD3+, CD4+, Th1, and CD8+ T cells were significantly increased, while NK, Th2, and Tc2 cells were significantly decreased, with a resulting increase in the Th1/Th2 and Tc1/Tc2 ratios. HU has the beneficial effect of restoring the abnormally elevated immune parameters in children with SCA. Hydroxyurea treatment restores the abnormal immune parameters in children with sickle cell anemia. HU treatment led to significantly increased CD3+, CD4+, Th1, and CD8+ T cells, while NK, Th2, and Tc2 cells were significantly decreased, with a resulting increase in the Th1/Th2 and Tc1/Tc2 ratios. Our study showed the impact of HU therapy on immune parameters in children with SCA.

Thalassemia and COVID-19: Susceptibility and Severity

Context: COVID-19 results in an imbalance between procoagulant and anticoagulant homeostatic mechanisms that could be complicated with thrombotic events. In β-thalassemia patients, the presence of comorbidities, iron overload, adrenal hypofunction, splenectomy, and chronic hypercoagulable state might increase the susceptibility to COVID-19 and its severity. Evidence Acquisition: The search was conducted in PubMed, Web of Science, and Scopus databases for the key terms of β-thalassemia/thalassemia and COVID-19 until July 2021. Results: The survey of published observational studies (mostly multicenter and case reports) indicated a lower prevalence of COVID-19 in β-thalassemia patients compared with the general population, as well as mild to moderate COVID-19 in these patients, especially in those without comorbidity. β-Thalassemia children were susceptible to COVID-19 but with less severity compared to adults. There is no report of pulmonary embolism and thrombotic events in β-thalassemia patients with COVID-19; however, coagulation abnormality and pulmonary microembolism have been found in these patients. Conclusions: Findings could be interpreted by the presence of high hemoglobin F (HbF) levels, the advantage of hydroxyurea (HU) therapy, splenectomy, and iron chelation therapy in these patients. However, due to the low sample size and studying mainly young patients, the results should be interpreted with caution, and it still needs more studies with a larger sample size to confirm these findings.

Evidence-Based Minireview: In young children with severe sickle cell disease, do the benefits of HLA-identical sibling donor HCT outweigh the risks?

Abstract In case 1, a 14-month-old male child with sickle cell disease (SCD) was referred for evaluation for an allogeneic hematopoietic stem cell transplant (HCT). The patient had a history of dactylitis 3 times in his first year of life and febrile episodes twice at the consult. His 4-year-old sister was found to be human leukocyte antigen (HLA) identical. The patient was started on hydroxyurea (HU) at 2.5 years of age. His parents again sought consultation when he was 5 years old because of concerns about his medical condition. At the time, the patient had experienced 2 vaso-occlusive pain episodes (VOEs) requiring hospitalization during the previous 2 years. He had also experienced intermittent pain crises requiring rest at home for 2 to 3 days. The child has not attended school in person due to the COVID-19 pandemic. The family is considering HCT but is ambivalent about it because of potential toxicity. In case 2, an 8-year-old female child is 3 years out from HCT for SCD from her HLA-identical sibling. Before HCT, despite receiving HU, she had experienced &amp;gt;5 VOEs requiring hospitalization and 2 episodes of acute chest syndromes in the previous 3 years. She had also been missing almost 50 days of school days each year. After HCT, she is now attending school regularly and participating in all normal age-appropriate activities. The parents believe that HCT has been transformative in their child's life.

Long noncoding RNAs transcribed downstream of the human β-globin locus regulate β-globin gene expression.

The five β-like globin genes (ε, Gγ, Aγ, δ and β) at the human β-globin gene locus are known to be expressed at specific developmental stages, although details of the underlying mechanism remain to be uncovered. Here we used an in vitro transcription assay to clarify the mechanisms that control this gene expression. We first tested nuclear RNA from HeLa cells using RT-qPCR and discovered a long noncoding RNAs (lncRNAs) within a 5.2-kb region beginning 4.4kb downstream of the β-globin gene coding region. We investigated nuclear RNA from K562 cells using a primer-extension assay and determined the transcription start sites (TSSs) of these lncRNAs. To clarify their functional role, we performed knockdown (KD) of these lncRNAs in K562 cells. Hydroxyurea (HU), which induces differentiation of K562 cells, increased haemoglobin peptide production, and the effect was enhanced by KD of these lncRNAs, which also enhanced upregulation of the γ-globin expression induced by HU. To confirm these results, we performed an in vitro transcription assay. Noncoding single-stranded RNAs inhibited β-globin expression, which was upregulated by GATA1. Furthermore, lncRNAs interacted with GATA1 without sequence specificity and inhibited its binding to its target DNA response element in vitro. Our results suggest that lncRNAs downstream of the β-globin gene locus are key factors regulating globin gene expression.

CLINICAL PROFILE AND MID-TERM OUTCOME OF CHILDREN WITH SICKLE CELL DISEASE TREATED WITH HYDROXYUREA

Objective:To study the clinical profile of patients with Sickle cell disease (SCD) and effect of Hydroxyurea (HU) on their haematological and biochemical profile. Method: This prospective observational study included children with Hb Electrophoresis proven SCD presenting in OPD or admitted in ward from November 2012 to May 2014. After detailed history, examination and baseline haematological and biochemical profile, Hydroxyurea was started and gradually increased. Primary outcome was reduction in symptoms, blood transfusion and hospital admissions. Secondary outcome was improvement in haematological and biochemical profile including Hb electrophoresis. Result: Study population included 70 patients with SCD with median age of 10.2 ( 2-18 ) years.Maximum children ( 91.5%) belonged to tribal population .Most children presented with body ache(70%) followed by abdominal pain(41.4%) and fever(34.3%). During 9 months of treatment with HU there was 81.4% decrease in clinical symptoms and significant reduction in hospital admissions(P&lt;0.0001) and blood transfusions(P&lt;0.0001). mean haemoglobin was increased to 9.4 mg/dl and there was significant improvement in Hb electrophoresis, mean Haemoglobin F (HbF) increased to 24.70% with P&lt;0.0001. Conclusion: In patients with SCD, treatment with hydroxyurea is associated with favourable short-term and mid-term outcomes.

A call to start hydroxyurea by 6months of age and before the advent of sickle cell disease complications.

A call to start hydroxyurea by 6months of age and before the advent of sickle cell disease complications.

Novel histone deacetylase inhibitor CT-101 induces γ-globin gene expression in sickle erythroid progenitors with targeted epigenetic effects

Induction of fetal hemoglobin (HbF) expression ameliorates the clinical severity and prolong survival in persons with sickle cell disease (SCD). Hydroxyurea (HU) is the only FDA-approved HbF inducer however, additional therapeutics that produce an additive effect in SCD are needed. To this end, development of potent Class I histone deacetylase inhibitors (HDACi) for HbF induction represents a rational molecularly targeted approach. In studies here, we evaluated CT-101, a novel Class I-restricted HDACi, a Largazole derivative, for pharmacodynamics, cytotoxicity, and targeted epigenetic effects. In SCD-derived erythroid progenitors, CT-101 induced HbF expression with additive activity in combination with HU. CT-101 preferentially activated γ-globin gene transcription, increased acetylated histone H3 levels, and conferred an open chromatin conformation in the γ-globin promoter. These data indicate CT-101 represents a strong potential candidate as a molecularly targeted inducer of HbF.

RNF4 Regulates the BLM Helicase in Recovery From Replication Fork Collapse.

Sumoylation is an important enhancer of responses to DNA replication stress and the SUMO-targeted ubiquitin E3 ligase RNF4 regulates these responses by ubiquitylation of sumoylated DNA damage response factors. The specific targets and functional consequences of RNF4 regulation in response to replication stress, however, have not been fully characterized. Here we demonstrated that RNF4 is required for the restart of DNA replication following prolonged hydroxyurea (HU)-induced replication stress. Contrary to its role in repair of γ-irradiation-induced DNA double-strand breaks (DSBs), our analysis revealed that RNF4 does not significantly impact recognition or repair of replication stress-associated DSBs. Rather, using DNA fiber assays, we found that the firing of new DNA replication origins, which is required for replication restart following prolonged stress, was inhibited in cells depleted of RNF4. We also provided evidence that RNF4 recognizes and ubiquitylates sumoylated Bloom syndrome DNA helicase BLM and thereby promotes its proteosome-mediated turnover at damaged DNA replication forks. Consistent with it being a functionally important RNF4 substrate, co-depletion of BLM rescued defects in the firing of new replication origins observed in cells depleted of RNF4 alone. We concluded that RNF4 acts to remove sumoylated BLM from collapsed DNA replication forks, which is required to facilitate normal resumption of DNA synthesis after prolonged replication fork stalling and collapse.

Entrapment of a Cytotoxic Drug into the Crystal Structure of Calcite for Targeted Drug Delivery.

Controlled drug release and targeted drug delivery can reduce systemic toxicity of chemotherapeutics by restricting drugs to the target organ and increasing the local concentration. As tumors and inflamed tissue are often surrounded by an acidic microenvironment, pH-responsive calcium carbonates (CaCO3) are promising vehicles for controlled drug delivery applications. The aim of this study was to evaluate the loading efficacy and release of a chemotherapeutic drug, Hydroxyurea (HU), into the crystal structure of calcite. Incorporation of HU did not alter the crystallinity, crystal size, or morphology of precipitated calcite crystals, as assessed by XRD and SEM. The amount of HU was quantified by High-Pressure Liquid Chromatography (HPLC) and showed that 6.7 ± 0.7 µg of HU could be for each milligram of calcite (0.016 mol% ± 0.002). In cell media, the optimal pH for controlled release was 5 (0.1 mg/mL released after 1 h). However, in vitro, pH below 6.5 was cytotoxic to human breast cancer cells (MCF-7). Direct contact studies, where particles were incubated with MCF-7 cells, showed that the amount of HU release from calcite was not high enough to kill the cell or arrest growth at pH 6.5. Pre-dissolved release studies, where the particles were pre-dissolved in acidic media to simulate complete drug release in vivo, pH neutralized, and exposed to the cells, showed that the amount of loaded HU reduced the survival/proliferation of MCF7. In conclusion, it is possible to integrate HU into the crystal structure of a calcite crystal and release the drug in vitro at concentrations that can slow the growth of cancer cells, without affecting calcite morphology and crystallinity. Further research is needed to investigate the in vivo behavior of the particles and whether the actual tumor pH is low enough to achieve complete drug release in vivo.

A Pharmacist-Managed Hydroxyurea Prescribing Protocol Improves Uptake and Optimization Among Patients with Sickle Cell Disease within the Southern Alberta Rare Blood and Bleeding Disorders (SARBBD) Comprehensive Care Program

Introduction: Sickle cell disease (SCD) is associated with major morbidity and mortality and yet many of our patients are not using the available disease modifying medication, hydroxyurea (HU). Furthermore, dose-titration of HU is required in order to achieve the maximum therapeutic benefit. Certain challenges can limit HU acceptance, such as misconceptions about safety, frequency of monitoring, and ease of access (i.e. insurance). Incorporating a pharmacist-managed HU hydroxyurea prescribing protocol into the SARBBD Comprehensive Care Program will help to address many of the barriers responsible for poor HU uptake among SCD patients and improve HU utilization.Objectives: To improve the uptake and optimization of HU among patients with Sickle Cell Disease within the SARBBD Comprehensive Care Program.Methods: Commencing in January 2020, clinic pharmacist support of 0.2 full-time equivalents (FTEs) was made available to the SARBBD program, and a pharmacist-led comprehensive HU prescribing protocol was adapted from the current CanHaem and National Heart, Lung, and Blood Institute guidelines. The clinical pharmacist was available for all Sickle Cell Disease clinic appointments, and was responsible for all aspects of HU management, including educating, counselling, and prescribing (titrating and monitoring as outlined in the prescribing protocol). It is worth noting that independent pharmacist prescribing is permitted in Alberta (Alberta College of Pharmacists, 2021).Patients were initiated on HU at a low dose of 500 mg daily to limit gastrointestinal sensitivities, and then increased to 1000 mg daily after one week. Thereafter the dose was titrated every 2-4 weeks as permitted by the patient's tolerance and laboratory parameters (i.e., CBC, liver and renal function, reticulocyte count) up to their maximum tolerated dose (MTD), defined as the maximum dose that maintains neutrophils ≥ 1.5 x 10 9/L, platelets > 80 x 10 9/L, and hemoglobin > 50 x 10 9/L. Following HU initiation and after every laboratory visit, the clinical pharmacist followed-up with patients via telephone to discuss HU tolerance, adherence, and dosing. Perceived benefits (i.e., pain episodes), medication supply, drug access (insurance), and planning for future follow-ups were also addressed as necessary.Results: As of January 2020, the SARBBD program provided care to 119 patients with SCD. Of those patients, 7 patients were managed with a transfusion exchange protocol, and therefore were not considered HU candidates. Of the 112 eligible SCD patients, 39 (34.8%) were already on HU therapy, 15 of whom were at MTD (38.4% of HU patients, 13.4% of 112 eligible SCD population). By June 2021 (18 months of pharmacist managed HU), there were 123 eligible SCD patients, of whom 71 were on HU (57.7%), with 37 at MTD (52.1% of HU patients, 30.1% of total eligible SCD population). Every month on average the pharmacist; has 27 interactions (phone, email) with SCD patients, reviews 18 lab reports, initiates HU for 2 patients, and will make over 4 dose adjustments.A majority of patient interactions involved educating patients on HU, and addressing common misconceptions about HU adverse effects and risks. Further, a significant proportion of HU initiations required pharmacist assistance with insurance authorization. Overall, patient acceptance of the pharmacist-managed HU prescribing was positive. One patient commented, “Working with [the pharmacist] has been great as he diligently has been able to keep a close eye on my blood results while making adjustments to my dosage of HU, without requiring a visit to the doctor. This was great as it didn't tie the doctors up, but also I was able to communicate with [the pharmacist] and get the same information at a convenient time. [The pharmacist] has also been extremely supportive, open and positive while answering questions”.Conclusion: Incorporating a pharmacist into the SARBBD program, as well as implementing a pharmacist-managed HU prescribing protocol has led to improved HU uptake and optimization. In addition, a greater proportion of patients have been able to reach MTD. The most common barriers to HU utilization, such as miseducation, frequency of laboratory monitoring, and medication access, can be overcome with dedicated pharmacist involvement.Funding: Sickle Cell Disease Association of Canada (SCDAC) grant and Novo Nordisk Investigator Initiated Grant DisclosuresPoon: University of Calgary: Current Employment; Bayer: Honoraria, Research Funding; CSL-Behring: Honoraria, Research Funding; Bioverativ/Sanofi: Honoraria; Novo Nordisk: Honoraria; Pfizer: Honoraria; Roche: Honoraria; Takeda: Honoraria. Lee: Bayer: Research Funding, Speakers Bureau; Biovertiv/Sanofi: Honoraria, Research Funding; CSL Behring: Honoraria; Novo Nordisk: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Roche: Honoraria; Takeda: Honoraria.