Red blood cell transfusion therapy for sickle cell patients with frequent painful events

Sickle cell disease: combination new therapies vs. CRISPR-Cas9 potential and challenges - review article

In 2022, sickle cell disease (SCD) continues to affect the lives of millions of people, being one of the most frequently inherited blood disorders worldwide. Recently, several new therapies have been FDA approved for the treatment of SCD. The complexity of the pathophysiology of sickling has given opportunity to the evolution of several modalities of therapies. Nonetheless, the potential for complementary targeting of HbS polymerization, vasocclusion, and other inflammatory pathways remains controversial. None of these drugs can be considered a single curative line of treatment. With the advancement of CRISPR/Cas9 technology, autologous transplant of gene-edited hematopoietic stem cells could possibly provide a cure for most patients with SCD. The advantage of this approach over the conventional stem cell transplantation is that it decreases the need for immuno-suppressive drugs and the risk of graft-versus-host disease. In addition, recent technological advances can reduce the off-target effects, but long-term monitoring is needed to ensure the reliability of these methods in the clinical setting. This review explores the efficacy and safety of combination therapies and contrasting this alternative with the challenges that exist with sickle cell gene therapy using CRISPR.

Global burden of transfusion in sickle cell disease

Sickle cell disease (SCD) is the most common hereditary hemoglobinopathy. The underlying pathophysiology of the red blood cell (RBC) leads to pan-systemic complications which manifest at an early age. While curative and disease-modifying treatments exist for SCD, a key intervention in the management and treatment of SCD is RBC transfusion, which can alleviate or prevent many complications. SCD patients often require chronic RBC transfusion therapy which can result in complications, such as iron overload, alloimmunization and infection. In low- and middle-income countries (LMICs), SCD patients lack appropriate access to healthcare such as newborn screening, health education, prophylaxis for infection, and treatments to reduce both mortality and SCD-related adverse effects. Poor access to RBCs for transfusion, coupled with donated blood not meeting safety standards set by the World Health Organization, presents a significant barrier for patients requiring chronic transfusions in LMICs. Unmet needs associated with blood collection, blood component processing and recipient matching all pose a serious problem in many LMICs, although this varies depending on geographic location, political organizations and economy. This review aims to provide an overview of the global burden of SCD, focusing on the availability of current treatments and the burden of chronic RBC transfusions in patients with SCD.

Comprehensive guide to managing a chronic automated red cell exchange program in sickle cell disease

Sickle cell disease (SCD) is associated with significant morbidity and mortality, and limits both the quality and quantity of life. Transfusion therapy, specifically automated red cell exchange (aRCE), plays a key role in management of SCD and is beneficial for certain indications in the chronic, outpatient setting. The approach to maintain a successful chronic aRCE program for SCD is multifaceted. This review will highlight important considerations including indications for aRCE, patient selection, transfusion medicine pearls, vascular access needs, complications of therapy, aRCE prescription, and therapy optimization. Moreover, the importance of a multidisciplinary approach with frequent communication between the services involved cannot be overstated. Ultimately, the underlying goal of a chronic RCE program is to improve the quality of life and longevity of patients with SCD.

Medical and Non-medical Costs of Sickle Cell Disease and Treatments from a US Perspective: A Systematic Review and Landscape Analysis

BACKGROUND

Sickle cell disease (SCD) is a complex genetic disorder that manifests in infancy and progresses throughout life in the form of acute and chronic complications. As the upfront costs of potentially curative, genetic therapies will likely be high, an assessment and comprehensive characterization of the medical and non-medical cost burden will inform future decision making.

OBJECTIVE

We sought to systematically summarize the existing literature surrounding SCD medical and non-medical costs.

METHODS

We searched MEDLINE and EMBASE (2008-2020) and identified US-based studies that detailed medical or non-medical costs. Eligible studies provided empirical estimates about any aspect of cost or SCD individuals of all ages and their caregivers. Study quality was assessed using the Newcastle-Ottawa Scale, and costs were adjusted to 2019 US$.

RESULTS

Search queries returned 479 studies, with 342 from medical burden searches and 137 from non-medical burden searches, respectively. Herein, we report the results of the 40 studies that contained relevant cost information: 39 detailed medical costs and 1 detailed non-medical costs. Costs were higher for SCD patients when compared with non-SCD individuals (cost difference range: $6636-$63,436 annually). The highest medical cost component for SCD patients was inpatient ($11,978-$59,851 annually), followed by outpatient and then pharmacy. No studies characterized the cost burden throughout the lifetime disease trajectory of an SCD individual, and no studies captured caregiver or productivity costs.

CONCLUSION

Our results reveal an incomplete characterization of medical and non-medical costs within SCD. A deeper understanding of the medical and non-medical cost burden requires completion of additional studies that capture the burden across the patient's lifetime, in addition to expression of the impact of existing and emergent health technologies on disease trajectory.

Long-term Use of Eculizumab for Prolonged Hemolysis Following a Delayed Hemolytic Transfusion Reaction in Pediatric Sickle Cell: A Case Report

Complement activation has been implicated in delayed hemolytic transfusion reaction (DHTR) in patients with sickle cell disease (SCD), and eculizumab has been reported as an effective treatment for patients with DHTR. Previously reported patients with SCD and DHTR responded well after a few doses of eculizumab. We report on the long-term use of eculizumab in a pediatric sickle cell patient with prolonged hemolysis of unknown etiology after a DHTR who had a slow and less sustained response. Long-term use of eculizumab in this young patient with SCD was successful with limited adverse effects.

Non-crisis related pain occurs in adult patients with sickle cell disease despite chronic red blood cell exchange transfusion therapy

BACKGROUND

Chronic red blood cell transfusions reduce acute care utilization for sickle cell disease (SCD) pain. However, little is known about whether chronic transfusions treat or prevent the development of non-crisis pain. We investigated patient-report of pain in adults with SCD receiving chronic exchange transfusions (CET) compared to adults not on CET with similar disease characteristics.

STUDY METHOD AND DESIGN

Eleven participants receiving chronic exchange transfusion (CET) for at least one year were compared to 33 participants not receiving CET. Participants completed validated patient-reported outcomes regarding pain impact and quality of life at regularly scheduled visits or before CET. One year of health care utilization and opioid prescriptions were examined.

RESULTS

After 1:1 propensity matching was performed for age, genotype, WBC and neutrophil counts, patients on CET had lower Pain Impact scores (-5.1, p = 0.03) and higher Neuropathic (7.4, p < 0.001) and Nociceptive Pain Quality (3.7, p < 0.001) scores, all indicating worse pain. However, CET was associated with a reduction in annual all cause admissions (-3.1, p < 0.001), length of stay (-2.1 days, p < 0.001) and ED visits (-2.7, p < 0.001). CET was not associated with differences in opioids dispensed.

CONCLUSIONS

After adjusting for disease characteristics, CET was associated with worse pain impact and neuropathic and nociceptive pain quality, lower health care utilization and with similar levels of opioids dispensed. This data suggest that CET may reduce hospitalizations for acute pain but may not adequately treat nociceptive or neuropathic pain in SCD.

American Society of Hematology 2020 guidelines for sickle cell disease: management of acute and chronic pain

BACKGROUND

The management of acute and chronic pain for individuals living with sickle cell disease (SCD) is a clinical challenge. This reflects the paucity of clinical SCD pain research and limited understanding of the complex biological differences between acute and chronic pain. These issues collectively create barriers to effective, targeted interventions. Optimal pain management requires interdisciplinary care.

OBJECTIVE

These evidence-based guidelines developed by the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in pain management decisions for children and adults with SCD.

METHODS

ASH formed a multidisciplinary panel, including 2 patient representatives, that was thoroughly vetted to minimize bias from conflicts of interest. The Mayo Evidence-Based Practice Research Program supported the guideline development process, including updating or performing systematic reviews. Clinical questions and outcomes were prioritized according to importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used, including GRADE evidence-to-decision frameworks, to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel reached consensus on 18 recommendations specific to acute and chronic pain. The recommendations reflect a broad pain management approach, encompassing pharmacological and nonpharmacological interventions and analgesic delivery.

CONCLUSIONS

Because of low-certainty evidence and closely balanced benefits and harms, most recommendations are conditional. Patient preferences should drive clinical decisions. Policymaking, including that by payers, will require substantial debate and input from stakeholders. Randomized controlled trials and comparative-effectiveness studies are needed for chronic opioid therapy, nonopioid therapies, and nonpharmacological interventions.

Characterizing bulk rigidity of rigid red blood cell populations in sickle-cell disease patients

In this work, we utilized a parameterization model of ektacytometry to quantify the bulk rigidity of the rigid red blood cell (RBC) population in sickle cell disease (SCD) patients. Current ektacytometry techniques implement laser diffraction viscometry to estimate the RBC deformability in a whole blood sample. However, the diffraction measurement is an average of all cells present in the measured sample. By coupling an existing parameterization model of ektacytometry to an artificially rigid RBC model, we formulated an innovative system for estimating the average rigidity of the rigid RBC population in SCD blood. We demonstrated that this method could more accurately determine the bulk stiffness of the rigid RBC populations. This information could potentially help develop the ektacytometry technique as a tool for assessing disease severity in SCD patients, offering novel insights into the disease pathology and treatment.

Brief Screening Measures Identify Risk for Psychological Difficulties Among Children with Sickle Cell Disease

Children with sickle cell disease (SCD) experience disproportionately high rates of psychological problems. Our goal was to examine the clinical utility of psychological screening measures to identify children with such problems in medical settings. Caregivers completed screening measures assessing social-emotional problems, ADHD symptoms, executive dysfunction, and health-related quality of life for children with SCD (receiving either chronic blood transfusion or hydroxyurea) and their siblings. Our findings demonstrated that screening measures identified clinically elevated symptoms in children with SCD that had not been previously reported. Scores for siblings were for the most part in the normal range. The number of days hospitalized (but not cerebral infarct status) predicted higher scores, emphasizing the challenges associated with SCD complications. Overall, our findings support the notion that screening measures reduce the need for reliance on medical provider judgment for psychological referrals and increase equitability in access to services. Early identification resulting in early intervention has contributed substantially to improved psychological functioning in many contexts, and it is thus likely that such improvements would also be achieved in this uniquely vulnerable population.

Patient and family experience with chronic transfusion therapy for sickle cell disease: A qualitative study

Background

There is a limited understanding of the patient and family experience of Chronic Transfusion Therapy (CTT) for prevention of complications of Sickle Cell Disease (SCD). We sought to understand patient and family experience with CTT using qualitative methods.

Methods

Fifteen parents of children < 18 years old and nine children 12–18 years old with SCD who were receiving CTT for > 1 year were interviewed using a semi-structured interview format, and interviews were analyzed using open coding methods.

Results

Four themes created a narrative of the patient and family experience of CTT: 1) Burden of CTT, 2) Coping with CTT, 3) Perceived benefits and risks of CTT, and 4) Decision making regarding CTT. Participants reported substantial burden of CTT, including the impact of CTT on daily life and family, distress about venous access, burden of chelation therapy, and anxiety about CTT complications. Participants described how they coped with CTT. Participants reported increased energy, decreased pain, fewer hospitalizations, and stroke prevention with CTT, but also recognized complications of CTT, though awareness was limited in adolescents. Parents described sharing in the informed decision-making process with their healthcare provider about CTT, but adolescent patient participants reported that they were not involved in this process.

Conclusions

CTT is associated with significant patient and family burden. Support from family, healthcare providers and school may help individuals cope with some of this burden. These findings provide the basis for future studies to identify strategies to mitigate the burden of CTT and improve the patient experience with this therapy. Future studies should also systematically assess patient knowledge about the key components of CTT and chelation using quantitative assessments.

The controversial role of red cell transfusions for sickle cell pain

PURPOSE OF REVIEW

Red cell transfusions are one of the most common and important therapies used for patients with sickle cell disease (SCD). For prevention of strokes, there is abundant evidence that transfusions are efficacious, whereas for other indications, such as prevention of pain, there are less data. Nonetheless, with few therapeutic options, the use of transfusion for prevention of acute pain has increased in children and adults with SCD without a clear understanding of its benefits.

RECENT FINDINGS

Although it makes conceptual sense that red cell transfusions would prevent pain that arises from vaso-occlusion, we now know that the mechanism of pain is more complex than vaso-occlusion alone. Recent taxonomies recognize a chronic pain syndrome that is both common in adults with SCD and affects the presentation of acute pain. It is not known if acute pain on the background of chronic pain responds differently to sickle cell therapies, such as hydroxyurea and blood transfusion.

SUMMARY

In this review, we will examine the studies that have investigated whether red cell transfusions are efficacious for preventing pain. In the absence of high-quality data that specifically addresses this question, we will outline our approach, which might soon change with new drugs and curative therapies on the horizon.