The field of hematopoietic stem cell transplant (HSCT) has made ground-breaking progress in the treatment of many malignant and nonmalignant conditions. It has also pioneered the concepts of stem cell therapy and immunotherapy as a tool against cancer. The success of transplant for hematologic malignancies derives both from the ability to treat patients with intensive chemoradiotherapy and from potent graft-versus-leukemia (GVL) effects mediated by donor immunity. Additionally, HSCT has been a curative therapy for several nonmalignant hematologic disorders through the provision of donor-derived hematopoiesis and immunity. Preclinical and clinical research in the field has contributed to an advanced understanding of histocompatibility, graft-versus-host disease (GVHD), GVL effect, and immune reconstitution after transplant. Improved donor selection, tailored conditioning regimens, and better supportive care have helped reduce transplant-related morbidity and mortality and expanded access. The development of unrelated donor registries and increased utilization of cord blood and partially matched related donor transplants have ensured a donor for essentially everyone who needs a transplant. However, significant barriers still remain in the form of disease relapse, GVHD infectious complications, and regimen-related toxicities. Recent developments in the field of cellular therapy are expected to further improve the efficacy of transplant. In this review, we discuss the current science of HSCT from a historical perspective, highlighting major discoveries. We also speculate on future directions in this field. Cancer Res; 76(22); 6445–51. ©2016 AACR.

The use of post-transplantation cyclophosphamide (PTCy) for graft-versus-host disease (GVHD) prophylaxis in recipients of haploidentical and fully matched transplantations is on the increase. Published studies have reported an increased incidence of cytomegalovirus (CMV) infection with the use of PTCy. Limited data exist on the incidence and outcomes of infection with non-CMV herpesviruses (NCHV) in this setting. The aim of this study was to evaluate the cumulative incidence of NCHV infections and the association of NCHV infections with transplantation-specific outcomes in recipients of haploidentical transplantation with PTCy (HaploCy), matched sibling donor transplantation with PTCy (SibCy), and matched sibling donor transplantation with calcineurin inhibitor-based prophylaxis (SibCNI). We hypothesized that, like CMV infection, HaploCy recipients of also will have a higher risk of NCHV infections. Using the Center for International Blood and Marrow Transplantation Research database, we analyzed 2765 patients (HaploCy, n = 757; SibCNI, n = 1605; SibCy, n = 403) who had undergone their first hematopoietic stem cell transplantation (HCT) between 2012 and 2017 for acute myelogenous leukemia, acute lymphoblastic leukemia, or myelodysplastic syndrome. The cumulative incidence of NCHV at 6 months post-NCT was 13.9% (99% confidence interval], 10.8% to 17.3%) in the HaploCy group, 10.7% (99% CI, 7.1% to 15%) in the SibCy group, and 5.7% (99% CI, 4.3% to 7.3%) in the Sib CNI group (P < .001). This was due primarily to a higher frequency of human herpesvirus 6 viremia reported in patients receiving PTCy. The incidence of Epstein-Barr viremia was low in all groups, and no cases of post-transplantation lymphoproliferative disorder were seen in either PTCy group. The incidence of NCHV organ disease was low in all 3 cohorts. The development of NCHV infection was associated with increased treatment-related mortality, particularly in the HaploCy group. There was no association with the development of GVHD, relapse, or disease-free survival. Patients in PTCy cohorts who did not develop NCHV infection had lower rates of cGVHD. This study demonstrates that the use of PTCy is associated with an increased risk of NCHV infection. The development of NCHV infection was associated with increased nonrelapse mortality, especially in the HaploCy group. Prospective trials should consider viral surveillance strategies in conjunction with assessment of immune reconstitution for a better understanding of the clinical relevance of viral reactivation in different HCT settings.

Key Points: EPO-EPOR signaling reduces UCB CD34+ HSPC engraftment through inhibition of BM homing and enhancement of erythroid differentiation. When used in clinical UCB transplantation, HBO therapy is safe and reduces EPO serum levels, potentially improving blood count recovery.

The evidence for conversion from brand name to generic equivalent cyclosporine is conflicting. Cyclosporine is a narrow therapeutic-range drug for which small variations in exposure may have severe clinical consequences for transplant patients. There is currently a lack of comparative outcome data relating to the pharmacokinetics of the reference formulation, Neoral, and generic formulations in transplant recipients. A major common concern is the potential inability to attain similar trough levels, an issue that can be easily corrected by ongoing therapeutic drug monitoring to ensure that the new steady state falls within an intended target range. Prospective clinical studies investigating the efficacy and safety of generic formulations in bothde novoand long-term transplant patients are also awaited. Until further evidence is available on the conversion of transplant patients to or between generic formulations of cyclosporine, any transfer to a different cyclosporine formulation should be undertaken with close supervision. The best available information to date, however, does not support the frequently held but unsubstantiated belief that generic preparations of immunosuppressive drugs are not as effective as brand names or that conversion from brand to generic is associated with significant danger. This paper attempts to initiate a discussion of these issues.