Effect of Donor Age and Donor Relatedness on Time to Allogeneic Hematopoietic Cell Transplantation in Acute Leukemia.

Relapse after allogeneic hematopoietic cell transplantation (HCT) for acute leukemia can be reduced when pursued early after first complete remission. The impact of donor age and donor relatedness on the time from diagnosis to transplant in patients with acute leukemia was examined to clarify the design of future prospective studies that can address optimal donor choice. Files of 100 consecutive patients undergoing transplantation for leukemia were reviewed. Recipients of related donors (RDs) and unrelated donors (UDs) were not significantly different in terms of recipient gender, age, underlying diagnosis, disease risk index, graft source, or donor HLA match. UDs were significantly younger than RDs (median age, 29 versus 51, P < .001). Multivariate linear regression revealed that when controlling for age of donor and recipient, the time from diagnosis to transplant was 35% longer with UDs compared with RDs (P = .018). No significant correlation was observed between donor and recipient age on length of time to transplant (P = .134 and P = .850, respectively), when controlling for other variables. The steps in UD procurement that contribute most to the longer time to transplant relate to activating the donor workup and scheduling the donor workup before cell collection. Understanding sources of delay in the transplant process will help transplant centers and UD registries reduce the time to transplant for patients with acute leukemia and will provide necessary insight for the design of prospective controlled studies that can address optimal donor choice.

Primary Preventive Care of Hematopoietic Stem Cell Transplantation Survivors: Time to Educate and Empower Recipients and Providers.

Increasing use of hematopoietic stem cell transplantation (HCT) and improvements in recipient outcomes have led to a steady increase in the number of allogeneic HCT survivors. In addition to complications specific to the transplantation process, HCT recipients are at increased risk of developing cardiovascular disease (CVD) and subsequent neoplasm (SN). Strict surveillance of risk factors for CVD and cancer in the general population is recommended as an essential component of long-term follow-up (LTFU) care of HCT survivors, but implementation of this has been suboptimal. Various models for improving the provision of survivorship care have been proposed, including a hybrid/combined care approach wherein the HCT provider manages transplantation-specific complications and the primary care physician (PCP) provides general medical care, including surveillance and aggressive management of CVD risk factors and screening for SN. This model also offers a practical approach to LTFU care for HCT survivors who live at a distance from the HCT center, which is a reality for many recipients of HCT at The Ottawa Hospital (TOH). As the success of such a hybrid approach to survivorship care depends on the engagement of HCT recipients with their PCP and compliance with recommended general population surveillance, the aim of the present study was to assess the rates of PCP attendance and adherence to recommended preventive medicine interventions in the years immediately before and after HCT. We hypothesized that rates would be suboptimal and planned to use these results as a baseline for an educational initiative aimed at increasing awareness of HCT recipients and their PCPs about embracing preventive survivorship care. This was a single-center cohort study of allogeneic HCT recipients who underwent transplantation at TOH with linkage to population-based health administrative data. Published clinical practice guidelines were used to define recommended screening for CVD risk factors and cancer. The rates of annual PCP visits and utilization of recommended preventive care interventions in the 5 years before and after HCT were calculated for all eligible patients. Between 2014 and 2020, 409 patients with provincial health care coverage underwent allogeneic HCT at TOH. The median patient age was 51 years (range, 15 to 73 years), with a male predominance (60.9%). Approximately one-quarter of recipients did not attend a PCP visit in the 5 years before and after transplantation, and this proportion increased to one- third in the fifth year post-HCT. Among those recipients who were eligible, only 20% to 25% underwent recommended screening for dyslipidemia and diabetes. Cancer screening rates were also low, at 16% to 18% for cervical cancer, 18% to 22% for colon cancer, and 30% to 31% for breast cancer. These results highlight the need to increase awareness of HCT recipients and their PCPs about the risk of developing CVD and SN post-transplantation and to emphasize the potential to mitigate this risk by adhering to recommendations for surveillance to enable prompt intervention. Patient education should incorporate this information and empower HCT survivors to actively engage in their follow-up care and optimize their long-term outcomes.

Autologous Hematopoietic Stem Cell Transplantation for Liver Transplant Recipients With Recurrent Primary Sclerosing Cholangitis: A Pilot Study.

BACKGROUND: Primary sclerosing cholangitis (PSC) is an indication for liver transplantation, but recurrence after liver transplantation is associated with poor outcomes often requiring repeat transplantation. We investigated whether autologous hematopoietic stem cell transplantation (aHSCT) could be used to stop progression of recurrent PSC and promote operational tolerance. METHODS: Twelve patients with recurrent PSC were fully evaluated and 5 were selected for aHSCT. Autologous hematopoietic stem cells were collected, purified by CD34 immunomagnetic selection, and cryopreserved. Immunoablation using busulfan, cyclophosphamide, and rabbit antithymocyte globulin was followed by aHSCT. The primary endpoint of the study was the establishment of operational tolerance defined as lack of biochemical, histologic, and clinical evidence of rejection while off immunosuppression at 2 y post-aHSCT. RESULTS: Two of the 5 patients achieved operational tolerance with no clinical or histologic evidence of PSC progression or allorejection. A third patient developed sinusoidal obstruction syndrome following aHSCT requiring repeat liver transplantation but has no evidence of PSC recurrence while on sirolimus monotherapy now >3 y after aHSCT. A fourth patient was weaned off immunosuppression but died 212 d after aHSCT from pericardial constriction. A fifth patient died from multiorgan failure. Immunosuppression-free allograft acceptance was associated with deletion of T-cell clones, loss of autoantibodies, and increases in regulatory T cells, transitional B cells, and programmed cell death protein-1 expressing CD8+ T cells in the 2 long-term survivors. CONCLUSIONS: Although operational tolerance occurred following aHSCT, the high morbidity and mortality observed render this specific protocol unsuitable for clinical adoption.

Consensus Recommendations for MRD Testing in Adult B-Cell Acute Lymphoblastic Leukemia in Ontario.

Measurable (minimal) residual disease (MRD) is an established, key prognostic factor in adult B-cell acute lymphoblastic leukemia (B-ALL), and testing for MRD is known to be an important tool to help guide treatment decisions. The clinical value of MRD testing depends on the accuracy and reliability of results. Currently, there are no Canadian provincial or national guidelines for MRD testing in adult B-ALL, and consistent with the absence of such guidelines, there is no uniform Ontario MRD testing consensus. Moreover, there is great variability in Ontario in MRD testing with respect to where, when, and by which technique, MRD testing is performed, as well as in how the results are interpreted. To address these deficiencies, an expert multidisciplinary working group was convened to define consensus recommendations for improving the provision of such testing. The expert panel recommends that MRD testing should be implemented in a centralized manner to ensure expertise and accuracy in testing for this low volume indication, thereby to provide accurate, reliable results to clinicians and patients. All adult patients with B-ALL should receive MRD testing after induction chemotherapy. Philadelphia chromosome (Ph)-positive patients should have ongoing monitoring of MRD during treatment and thereafter, while samples from Ph-negative B-ALL patients should be tested at least once later during treatment, ideally at 12 to 16 weeks after treatment initiation. In Ph-negative adult B-ALL patients, standardized, ideally centralized, protocols must be used for MRD testing, including both flow cytometry and immunoglobulin (Ig) heavy chain and T-cell receptor (TCR) gene rearrangement analysis. For Ph-positive B-ALL patients, MRD testing using a standardized protocol for reverse transcription real-time quantitative PCR (RT-qPCR) for the BCR-ABL1 gene fusion transcript is recommended, with Ig/TCR gene rearrangement analysis done in parallel likely providing additional clinical information.

Plerixafor in combination with chemotherapy and/or hematopoietic cell transplantation to treat acute leukemia: A systematic review and metanalysis of preclinical and clinical studies.

Leukemia-initiating cells localize to bone marrow niches via cell surface CXCR4 binding to stromal-derived factor 1 (SDF-1). Plerixafor, a CXCR4 antagonist, can mobilize and sensitize leukemia cells to cytotoxic therapy, and/or enhance the engraftment of healthy donor stem cells in the context of hematopoietic cell transplantation (HCT). A systematic review of preclinical and clinical studies was performed (updated May 1, 2020) to inform the design of definitive clinical trials and identified 19 studies. Pooled data from 10 preclinical in-vivo studies of AML and ALL in mouse models of leukemia revealed significant mobilization of leukemia cells into the peripheral circulation, decreased total blast burden and increased survival with plerixafor in addition to cytotoxic treatment compared to control animals. Two of 9 clinical studies compared outcomes to a control group. Plerixafor appears well tolerated and safe and can mobilize leukemia cells into the peripheral circulation. In patients with AML undergoing HCT, plerixafor given with the conditioning regimen appears safe and well tolerated. Engraftment, relapse and survival were not different from controls after limited follow-up. Studies in high risk patients with AML with longer follow-up are needed to understand the influence on relapse following treatment and on donor cell engraftment following HCT.