AABB23: Advancing Apheresis Collection to Further Gene Therapies

Gene therapies represent significant potential for treatment or cures for sickle cell disease and other health conditions. But to facilitate further advancement of gene therapy, more information is needed to better understand best practices for cell collection.

At a session titled “Optimizing Apheresis Collections to Enable Hematopoietic Stem Cell Gene Therapies,” held Saturday morning, experts spoke about the current practices, research designed to improve cell collections and the future potential of gene therapies.

One of the session’s speakers, Reuben P. Jacob, MD, medical director of apheresis service and associate director of transfusion medicine/blood bank in the Department of Pathology and Laboratory Medicine at Children's Healthcare of Atlanta, and assistant professor in the Department of Pediatrics at Emory University School of Medicine, noted that in recent years, gene therapy has increasingly made headlines and is a rapidly advancing area of the field. For current treatments for sickle cell disease, an allogeneic hematopoietic stem cell transplant remains the standard of care.

Jacob said that currently, gene therapy involves the introduction of nucleic acids into target cells for therapeutic purposes. In addition, additive gene therapy or the insertion of a corrected, mutated gene is then performed.

Typically, the collection of cells for gene therapy is done through apheresis. “Although the ideal dose is not established, we know that more is better and a backup is needed,” Jacob said. Jacob added that for patients with hemoglobinopathies, a significant reduction in hematopoietic stem cell collection efficiency is common.

Several important studies have assessed the optimal collection of cells in patients with sickle cell disease. He noted three key studies. The first, by Leonard et al, found that disease severity often impacts stem cell collection in patients with sickle cell disease. The second, by Sharma et al, demonstrated that hematopoietic stem cells are often not efficiently captured through standard apheresis collection in patients with sickle cell disease. The third study, by Avecilla et al, found that collection efficacy increased with two novel adjustments: heparin plus ACDA anticoagulation, and increased default packing factor.

Jacob said that to further advance gene therapy, several considerations need to be made. “Continued transfusion service support is needed,” he said, including red cell exchanges, collections, genotyping and alloimmunization history. In addition, access to health care for patients in need is critical. Various issues, including cost of technology, patient selection and support for clinical trials should be considered.