Successful hematopoietic stem cell transplant requires the infusion of a sufficient number of hematopoietic stem/progenitor cells (HSPCs) that are capable of homing to the bone marrow cavity and ...regenerating durable trilineage hematopoiesis in a timely manner. Stem cells harvested from peripheral blood are the most commonly used graft source in HSCT. Although granulocyte colony-stimulating factor (G-CSF) is the most frequently used agent for stem cell mobilization, the use of G-CSF alone results in suboptimal stem cell yields in a significant proportion of patients. Both the chemokine receptor CXCR4 and the integrin α(4)β(1) (very late antigen 4 (VLA-4)) have important roles in the homing and retention of HSPCs within the bone marrow microenvironment. Preclinical and/or clinical studies have shown that targeted disruption of the interaction of CXCR4 or VLA-4 with their ligands results in the rapid and reversible mobilization of hematopoietic stem cells into the peripheral circulation and is synergistic when combined with G-CSF. In this review, we discuss the development of small-molecule CXCR4 and VLA-4 inhibitors and how they may improve the utility and convenience of peripheral blood stem cell transplantation.
T cell malignancies represent a group of hematologic cancers with high rates of relapse and mortality in patients for whom no effective targeted therapies exist. The shared expression of target ...antigens between chimeric antigen receptor (CAR) T cells and malignant T cells has limited the development of CAR-T because of unintended CAR-T fratricide and an inability to harvest sufficient autologous T cells. Here, we describe a fratricide-resistant "off-the-shelf" CAR-T (or UCART7) that targets CD7+ T cell malignancies and, through CRISPR/Cas9 gene editing, lacks both CD7 and T cell receptor alpha chain (TRAC) expression. UCART7 demonstrates efficacy against human T cell acute lymphoblastic leukemia (T-ALL) cell lines and primary T-ALL in vitro and in vivo without the induction of xenogeneic GvHD. Fratricide-resistant, allo-tolerant "off-the-shelf" CAR-T represents a strategy for treatment of relapsed and refractory T-ALL and non-Hodgkin's T cell lymphoma without a requirement for autologous T cells.
At present, the only curative therapy for patients with T-cell malignancies is allogeneic stem cell transplant, which has associated risks and toxicities. Novel agents have been tried in relapsed ...T-cell acute lymphoblastic leukemia (T-ALL), but only one, with 20%–30% complete remission rates, has been approved by the US Food and Drug Administration. T-ALL is a heterogeneous disease, but it has universal overexpression of CD7 as well as several other T-cell markers, such as CD2 and CD5. T cells engineered to express a chimeric antigen receptor (CAR) are a promising cancer immunotherapy. Such targeted therapies have shown great potential for inducing both remissions and even long-term relapse-free survival in patients with B-cell leukemia and lymphoma. UCART7 for CD7+ T-cell malignancies is in development for treatment of relapsed T-ALL in children and adults. It may also have potential in other CD7+ hematologic malignancies that lack both effective therapies and targeted therapies. The challenges encountered and progress made in developing a novel fratricide-resistant “off-the-shelf” CAR-T (or UCART7) that targets CD7+ T-cell malignancies are discussed here.
Several barriers to physicians becoming clinical investigators exist, including inexperience, lack of available mentors, and inconsistent instructive approaches with varying degrees of participation ...during training. These barriers cause fewer hematology-oncology fellows to pursue academic careers. A consensus is needed on structuring education in clinical investigation paired with active participation in development of a clinical trial guided by a mentor with the goal of increasing fellow interest in clinical research and pursuit of careers in academic medicine.
The clinical trial development (CTD) program was initiated at Washington University School of Medicine in St. Louis in 2002 as a hands-on learning experience for hematology and oncology fellows in the design, implementation, and publication of clinical trials. Each fellow was required to identify a mentor and propose at least 1 prospective investigator-initiated clinical trial.
At the time of data abstraction in July 2023, 118 fellows had participated in the CTD program and initiated protocols in a variety of areas according to their interests. Fellows were included in data abstraction if their fellowship began in 2002 through 2021; the program is ongoing, and the most recent class will graduate in 2024. Disease types were evenly distributed between solid tumor oncology (60 51%) or classic and malignant hematology (58 49%). Ninety-three fellows (79%) obtained institutional review board approval, and 60 (65%) published their results. Among graduating fellows, 67 (66%) secured an academic faculty appointment. Fellows with institutional review board-approved projects had significantly higher odds of obtaining an academic faculty appointment (odds ratio, 4.96; 95% confidence interval, 1.54, 15.98; P = .007).Next StepsNext steps will be to further evaluate the effect of the mentorship network on early career productivity of trainees that graduate and the feasibility of extending the program to another institution.
In this study, investigators compared genome sequencing with cytogenetic analysis in 263 patients with acute myeloid leukemia or myelodysplastic syndromes. Prospective sequencing detected new genetic ...information that was not revealed by cytogenetic analysis in nearly 25% of the patients, which altered the risk category for most of these patients.
PURPOSE OF REVIEWMobilized peripheral blood stem cells are increasingly used for the reconstitution of hematopoiesis in autologous and allogeneic transplants. New agents and approaches are emerging ...to improve mobilization efficacy while reducing duration and toxicity of mobilization. The purpose of this review is to overview clinical experience with AMD3100 (plerixafor) and its role in stem cell mobilization.
RECENT FINDINGSAMD3100 is a bicyclam molecule that selectively and reversibly antagonizes the binding of stromal cell-derived factor-1 (SDF-1) to its receptor CXC motif receptor-4 (CXCR4) with subsequent egress of hematopoietic stem cells to the peripheral blood. AMD3100 safely and rapidly mobilizes stem cells in patients with lymphoma, myeloma and healthy donors, and is synergistic in combination with granulocyte-colony stimulating factor. In addition, AMD3100 disrupts the interaction between mouse and human leukemic blasts and the bone marrow stroma, mobilizing blasts to the peripheral blood and sensitizing them to chemotherapy.
SUMMARYAMD3100 was recently FDA-approved for stem cell mobilization in combination with granulocyte-colony stimulating factor in patients with non-Hodgkinʼs lymphoma and multiple myeloma. Studies are underway testing AMD3100 as an adjunct to chemotherapy in patients with refractory acute myelogenous leukemia (and other hematologic malignancies), as a strategy to sensitize leukemic cells to chemotherapy and improve clinical outcomes.
There is interest in using leukemia-gene panels and next-generation sequencing to assess acute myelogenous leukemia (AML) response to induction chemotherapy. Studies have shown that patients with AML ...in morphologic remission may continue to have clonal hematopoiesis with populations closely related to the founding AML clone and that this confers an increased risk of relapse. However, it remains unknown how induction chemotherapy influences the clonal evolution of a patient's nonleukemic hematopoietic population. Here, we report that 5 of 15 patients with genetic clearance of their founding AML clone after induction chemotherapy had a concomitant expansion of a hematopoietic population unrelated to the initial AML. These populations frequently harbored somatic mutations in genes recurrently mutated in AML or myelodysplastic syndromes and were detectable at very low frequencies at the time of AML diagnosis. These results suggest that nonleukemic hematopoietic stem and progenitor cells, harboring specific aging-acquired mutations, may have a competitive fitness advantage after induction chemotherapy, expand, and persist long after the completion of chemotherapy. Although the clinical importance of these “rising” clones remains to be determined, it will be important to distinguish them from leukemia-related populations when assessing for molecular responses to induction chemotherapy.
•Hematopoietic populations unrelated to the AML founding clone often expand after induction therapy, resulting in oligoclonal hematopoiesis.
PDF
