Shi, Patricia A.

ABSTRACT Prior surveys of chronic automated red blood cell exchange (RCE) for patients with sickle cell disease (SCD) have identified considerable procedural variability, especially with the use of isovolemic hemodilution red blood cell exchange (IHD‐RCE). We conducted a survey of chronic RCE practices among American Society for Apheresis (ASFA) members to identify opportunities for practice harmonization and future studies. The ASFA SCD Research Subcommittee developed a 72‐item survey of chronic RCE practices, with a focus on IHD‐RCE. The survey was validated internally and distributed by email to all ASFA members from September 2024 to February 2025. One survey response from each institution was retained for data analysis. Descriptive statistics were performed. Sixty‐two survey responses, including three from international institutions, were retained for analysis. Sixty‐one percent of respondents (38/62) reported using at least one fixed RCE target, with end hematocrit being the most common fixed parameter (40%, 25/62), followed by fraction of cells remaining (31%, 19/62) and hemoglobin S% (27%, 17/62). Most respondents (60%, 37/61) performed IHD‐RCE at their institution, though other details such as the minimum hematocrit, exclusion criteria, and response to adverse effects were variable. Consistent pre‐ and post‐RCE laboratory monitoring practices were reported. Consistent with earlier surveys, procedural variability in chronic RCE practices for patients with SCD is observed. This highlights opportunities to compare outcomes where practice variability exists. Consensus guidelines based on institutional practices with optimal outcomes should be developed.

Abstract Background Sickle cell disease (SCD) is a hemoglobinopathy with limited treatment options. Genetic modification of the patient's own hematopoietic stem cells (HSCs) offers an avenue to curative therapy using the patient's own cells. Many challenges exist in collecting sufficient numbers of starting material for manufacturing, beginning with the pre‐mobilization optimization of the patient to the mobilization, collection, and post‐collection phases. Study Design and Methods A working group within the Cellular Therapy Subcommittee of the American Society for Apheresis Clinical Applications Committee describes the challenges associated with apheresis collection of the starting material for gene therapy (GT) product manufacturing for patients with SCD and discusses potential strategies for overcoming these challenges. Results and Discussion Patients must undergo automated red blood cell exchange (RCE) to lower hemoglobin S in a relatively short window of time before apheresis collection of HSCs. The risks and benefits of transfusion as well as the logistics of providing adequate and appropriate blood products must be considered. Limited agents are available for mobilization of HSCs into the peripheral blood for collection and the timing of administration is short. Each collection cycle consists of RCE followed by at least three mobilization and apheresis collection events in addition to collecting backup cells. More than one cycle is typically needed to collect enough cells for GT drug product manufacturing. Optimization of patient factors and apheresis instrument parameters leads to better collection yields. Early and frequent ongoing coordination with all stakeholders involved is critical to developing personalized treatment plans for patients.

Abstract In July 2022, these guidelines were reviewed by an expert work group convened by ASH. Review included limited searches for new evidence and discussion of the search results. Following this review, the ASH Committee on Quality agreed to continue monitoring the supporting evidence rather than revise or retire these guidelines at this time. Limited searches and expert review will be repeated annually going forward until these guidelines are revised or retired. Background: Red cell transfusions remain a mainstay of therapy for patients with sickle cell disease (SCD), but pose significant clinical challenges. Guidance for specific indications and administration of transfusion, as well as screening, prevention, and management of alloimmunization, delayed hemolytic transfusion reactions (DHTRs), and iron overload may improve outcomes. Objective: Our objective was to develop evidence-based guidelines to support patients, clinicians, and other healthcare professionals in their decisions about transfusion support for SCD and the management of transfusion-related complications. Methods: The American Society of Hematology formed a multidisciplinary panel that was balanced to minimize bias from conflicts of interest and that included a patient representative. The panel prioritized clinical questions and outcomes. The Mayo Clinic Evidence-Based Practice Research Program supported the guideline development process. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to form recommendations, which were subject to public comment. Results: The panel developed 10 recommendations focused on red cell antigen typing and matching, indications, and mode of administration (simple vs red cell exchange), as well as screening, prevention, and management of alloimmunization, DHTRs, and iron overload. Conclusions: The majority of panel recommendations were conditional due to the paucity of direct, high-certainty evidence for outcomes of interest. Research priorities were identified, including prospective studies to understand the role of serologic vs genotypic red cell matching, the mechanism of HTRs resulting from specific alloantigens to inform therapy, the role and timing of regular transfusions during pregnancy for women, and the optimal treatment of transfusional iron overload in SCD.