Haploidentical Stem Cell Transplantation in Adult Haematological Malignancies

Home-Based Hematopoietic Cell Transplantation in the United States

Patients undergoing allogeneic (allo) and autologous (auto) hematopoietic cell transplantation (HCT) require extensive hospitalizations or daily clinic visits for the duration of their transplantation. Home HCT, wherein patients live at home and providers make daily trips to the patient's residence to perform assessments and deliver any necessary interventions, may enhance patient quality of life and improve outcomes. We conducted the first study of home HCT in the United States to evaluate this model in the US healthcare setting and to determine the effect on clinical outcomes and quality of life. This case-control study evaluated patients who received home HCT at Duke University in Durham, North Carolina, from November 2012 to March 2018. Each home HCT patient was matched with 2 controls from the same institution who had received standard treatment based on age, disease, and type of transplant for outcomes comparison. Clinical outcomes were abstracted from electronic health records, and quality of life was assessed via Functional Assessment of Cancer Therapy-Bone Marrow Transplant. Clinical outcomes were compared with Student's t-test or Fisher's exact test (continuous variables) or chi-square test (categorical variables). Quality of life scores were compared using the Student t-test. All analyses used a significance threshold of 0.05. Twenty-five patients received home HCT, including 8 allos and 17 autos. Clinical outcomes were not significantly different between the home HCT patients and their matched controls; home HCT patients had decreased incidence of relapse within 1 year of transplantation. Pre-HCT quality of life was well preserved for autologous home HCT patients. This Phase I study demonstrated that home HCT can be successfully implemented in the United States. There was no evidence that home HCT outcomes were inferior to standard-of-care treatment, and patients undergoing autologous home HCT were able to maintain their quality of life. A Phase II randomized trial of home versus standard HCT is currently underway to better compare outcomes and costs.

Current Trends on Hemopoietic Stem Cells

Advances in single-cell technology and genetic mouse models have resulted in the identification of new types of hemopoietic stem cells (HSC), resulting in baffling observations, suggesting a reconsideration of the long-held notion that all hematopoietic cells in the adult are derived from HSCs. The existence of long-lived HSC-independent hematopoiesis has led to the conclusion that despite the single hierarchical differentiation route that generates functional blood types, other differentiation routes exist in-vivo. Heterogeneity in the HSC population and the evolving knowledge around HSC has translated to it's improved application as a therapeutic tool for various blood disorders. The reprogramming of non-hematopoietic somatic and mature blood cells to pluripotency with their subsequent differentiation into hematopoietic stem cells/progenitor cells and the introduction of new generation sequencing holds the potential for the resolution of ambiguities involved in HSC bone marrow transplantation. There is a change in the paradigm for HSC transplantation donor selection. Donor choice favors haploidentical HCT than cord blood. This review provides a general overview of the current events around hemopoietic stem cells, with emphasis on the rising trend of HSC transplantation, especially haploidentical stem cell transplantation.

Haploidentical hematopoietic stem cell transplantation in aplastic anemia: a systematic review and meta-analysis of clinical outcome on behalf of the severe aplastic anemia working party of the European group for blood and marrow transplantation (SAAWP of EBMT)

Aplastic anemia (AA) is a serious hematological disorder, which is solely cured by hematopoietic stem cell transplantation (HSCT). Haploidentical HSCT is an emerging modality with encouraging outcomes in several blood conditions. The present study aims to comprehensively assess the feasibility and safety of haploidentical HSCT in patients with severe and very severe AA. It is a systematic review and meta-analysis of studies related to haploidentical stem cell transplantation in idiopathic AA investigating rates of successful engraftment, acute graft-versus-host disease (aGvHD), chronic GvHD (cGvHD), transplant-related mortality (TRM), and posttransplantation viral infections (including cytomegalovirus [CMV]) in patients with AA. The effects of reduced-intensity conditioning (RIC) and nonmyeloablative conditioning (NMA), as well as various GvHD prophylaxis regimens on these outcomes were evaluated. In total 15 studies were identified, (577 patients, 58.9% males), successful engraftment was observed in 97.3% of patients (95% CI, 95.9-98.7) while grades II-IV aGvHD and cGvHD were reported in 26.6% and 25.0%, respectively. The pooled incidence of TRM was 6.7% per year (95% CI, 4.0-9.4). RIC regimens were associated with higher proportions of successful engraftment (97.7% vs 91.7%, P = 0.03) and aGvHD (29.5% vs 18.7%, P = 0.008) when compared with NMA regimens with no differences in cGvHD or mortality incidence. When compared with methotrexate-containing regimens and other regimens, posttransplant cyclophosphamide-containing regimens reduced the rates of aGvHD (28.6%, 27.8%, and 12.8%, respectively, P = 0.02), CMV viremia (55.7%, 38.6%, and 10.4%, respectively, P < 0.001), and CMV disease in initially viremic patients (2.1%, 33.0%, and 0%, respectively, P < 0.001). We have concluded that Haploidentical HSCT was associated with promising outcomes in terms of successful engraftment and reduced complications. Future prospective trials are needed to identify the preferred conditioning regimen, GvHD prophylaxis, and graft source in the setting of haploidentical transplant for AA.

Tuning Natural Killer Cell Anti-multiple Myeloma Reactivity by Targeting Inhibitory Signaling via KIR and NKG2A

Natural killer (NK) cells are attractive candidates for allogeneic cell-based immunotherapy due to their potent antitumor effector function and good safety profile. NK cells express killer immunoglobulin-like receptors (KIRs) and the NKG2A receptor important for NK cells education as well as providing inhibitory signals upon encountering HLA-expressing target cells. Multiple myeloma (MM) is an example of a tumor expressing relatively high levels of HLA molecules. In this review, we discuss the functional relevance of inhibitory KIRs and NKG2A for NK cells anti-MM response and strategies to lower these inhibitory signaling to enhance clinical efficacy of allogeneic NK cells in MM.

Regulatory T cells and CD20+ B cells in pediatric very severe aplastic anemia: possible clinical markers for evaluating the therapeutic efficacy and prognosis

OBJECTIVES

To investigate the immune status of children with very severe aplastic anemia (VSAA), and evaluate the frequencies of CD20⁺ B cells and Regulatory T cells (Tregs) as potential markers for evaluating the therapeutic efficacy and prognosis.

METHODS

We systematically analyzed CD20⁺ B cells and Tregs using Flow Cytometry in 36 children with VSAA (14 newly diagnosed cases and 22 cases in remission after therapy with HDIVIG + r-ATG + CSA).

RESULTS

In newly diagnosed VSAA patients, the percentage of CD20⁺ B cells was higher than that in healthy children (P < .01), whereas the percentage of Tregs was lower than that in healthy children (P < .001). After treatment with HDIVIG + r-ATG + CSA, the percentage of CD20⁺ B cells in peripheral blood was decreased obviously, and the percentage of Tregs was significantly increased.

CONCLUSION

There is a moderate negative correlation between the percentage of Tregs and CD20⁺ B cells in our study. Our results shed light on the roles of Tregs and CD20⁺ B cells as therapeutic efficacy and prognostic markers of pediatric VSAA. Moreover, the mechanism underlying the decrease of blood Tregs and increase of CD20⁺ B cells in pediatric VSAA patients have been discussed, indicating that Tregs may suppress B cell responses.

Characterization of IFNγ-producing natural killer cells induced by cytomegalovirus reactivation after haploidentical hematopoietic stem cell transplantation

During human cytomegalovirus (CMV) infection after umbilical cord blood or HLA-matched hematopoietic stem cell transplantation (HSCT), a population of NKG2C-expressing natural killer (NK) cells expand and persist. The expanded NK cells express high levels of inhibitory killer immunoglobulin-like receptors (KIR) specific for self-HLA and potently produce IFNγ. However, it remains unknown whether similar events would occur after haploidentical HSCT (haplo-HSCT). Here, we demonstrated that IFNγ-producing NK cells were expanded in haplo-HSCT patients with CMV reactivation. We then identified these expanded cells as a subset of CD56^dim NK cells that expressed higher levels of both NKG2C and KIR, but lower level of NKG2A. Functionally, the subset of NK cells expressing NKG2C and self-KIR in patients with CMV reactivation accounted for IFNγ production in response to K562 cells. However, these phenomena were not observed in patients without CMV reactivation. We therefore characterized a subset of NK cells with the CD56^dim, NKG2C⁺, and self-KIR⁺ phenotype that expanded and were responsible for IFNγ production during CMV infection after haplo-HSCT. Together, these findings support a notion that CMV reactivation induces expansion of more mature NK cells with memory-like features, which contributes to long-term control of both CMV infection and leukemia relapse after haplo-HSCT.

Systematic review of health state utility values for acute myeloid leukemia

Background

Cost-utility analyses for acute myeloid leukemia (AML) require health state utility values (HSUVs) in order to calculate quality-adjusted life-years (QALYs) for each health state.

Aim

This study reviewed AML-related HSUVs that could be used in economic evaluation studies.

Materials and methods

EMBASE, MEDLINE, and Cochrane databases were searched from January 2000 to November 2016 for relevant studies that reported quality of life (QoL) and HSUVs in AML. Identified relevant European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 values were mapped to HSUVs. HSUVs for each health state in the AML treatment pathway were then collated.

Results

Ten relevant studies were identified. Six were cost-effectiveness analyses utilizing HSUVs for calculation of QALYs, one was an effectiveness analysis (incremental QALY), and two were QoL studies reporting AML-specific utilities. An additional study reported QoL for patients undergoing stem cell transplantation (SCT). Since no study reported HSUVs for relapse, values from a study of secondary AML patients who failed prior treatment for myelodysplastic syndrome were used. Where multiple HSUVs were available, collected values were given priority over assumed values. AML treatment (induction, consolidation, or SCT) was associated with decreased HSUV, while post-treatment complete remission led to increased HSUV.

Conclusion

There are some methodologically robust HSUVs that can be directly used in economic evaluations for AML. Careful interpretation is advised considering significant differences in methodologies and patient population (inclusion, size). We need to develop HSUVs with larger-sized studies, making greater use of condition-specific data.

High ocular CMV copies and mismatched receipts may predict poor visual prognosis in CMV retinitis patients following allogeneic haematopoietic stem cell transplantation

BACKGROUND

To summarize the clinical characteristics and potential factors affecting the visual outcomes in patients with cytomegalovirus retinitis following allogeneic haematopoietic stem cell transplantation (HSCT).

METHODS

This retrospective study enrolled 12 patients (19 eyes) with cytomegalovirus retinitis after HSCT at Guangzhou First People's Hospital in China between January 2013 and December 2014. Demographic and clinical characteristics, ocular manifestations and visual outcomes were evaluated by reviewing medical records at the Departments of Hematology and Ophthalmology. All patients were followed up at least 6 months after stopping antiviral therapy. The visual outcome was defined as improvement, stabilization and deterioration.

RESULTS

The subjects were composed of 7 human leucocyte antigen-matched and 5 mismatched receipts. All patients received combined systemic and intravitreous antiviral therapy. Eleven eyes gained improved or stabilized visual acuity, while 8 eyes suffered deterioration. Eyes with cytomegalovirus load less than 1 × 10⁴ copies/ml in vitreous accounted for higher rate in eyes with good visual prognosis than those with cytomegalovirus copies above 1 × 10⁴ copies/ml (52.63% vs 5.26%, P < 0.001). Human leucocyte antigen-matched receipts gained better visual prognosis than those mismatched ones (47.37% vs10.53%, P < 0.05). The virus types, cytomegalovirus peak in the blood, involved retinal zone and size had no influence on the visual outcomes (all P > 0.05).

CONCLUSIONS

High ocular cytomegalovirus copies and mismatched receipts may be potential adverse factors affecting visual outcomes in cytomegalovirus retinitis patients following allogeneic HSCT.

Immune tolerance induction by nonmyeloablative haploidentical HSCT combining T-cell depletion and posttransplant cyclophosphamide

The establishment of safe approaches to attain durable donor-type chimerism and immune tolerance toward donor antigens represents a major challenge in transplantation biology. Haploidentical hematopoietic stem cell transplantation (HSCT) is currently used for cancer therapy either as a T-cell-depleted megadose HSCT following myeloablative conditioning or with T-cell-replete HSCT following nonmyeloablative conditioning (NMAC) and high-dose posttransplant cyclophosphamide (PTCY). The latter approach suffers from a significant rate of chronic graft-versus-host disease (GVHD), despite prolonged immunosuppression. The use of T-depleted grafts, although free of GVHD risk, is not effective after NMAC because of graft rejection. We now demonstrate in mice conditioned with NMAC that combining the power of high-dose PTCY with T-cell-depleted megadose HSCT can overcome this barrier. This approach was evaluated in 2 patients with multiple myeloma and 1 patient with Hodgkin lymphoma. The first myeloma patient now followed for 25 months, exhibited full donor-type chimerism in the myeloid and B-cell lineages and mixed chimerism in the T-cell compartment. The second myeloma patient failed to attain chimerism. Notably, the low toxicity of this protocol enabled a subsequent successful fully myeloablative haploidentical HSCT in this patient. The third patients was conditioned with slightly higher total body irradiation and engrafted promptly. All patients remain in remission without GVHD. Both engrafted patients were able to control cytomegalovirus reactivation. Enzyme-linked immunospot analysis revealed immune tolerance toward donor cells. Our results demonstrate a novel and safer nonmyeloablative haplo-HSCT offering a platform for immune tolerance induction as a prelude to cell therapy and organ transplantation.

In patients with chronic aplastic anemia, bone marrow-derived MSCs regulate the Treg/Th17 balance by influencing the Notch/RBP-J/FOXP3/RORγt pathway

The standard treatment for aplastic anemia (AA) in young patients is a matched sibling hematopoietic stem cell transplant. Transfusion of a chronic AA patient with allogeneic bone marrow–derived mesenchymal stromal cells (BMMSCs) is currently being developed as a cell-based therapy, and the safety and efficacy of such transfusions are being continuously improved. Nevertheless, the mechanisms by which BMMSCs exert their therapeutic effects remain to be elucidated. In this study, mesenchymal stromal cells (MSCs) obtained from bone marrow donors were concentrated and intravenously injected into 15 chronic AA patients who had been refractory to prior immunosuppressive therapy. We showed that BMMSCs modulate the levels of Th1, Th2, Th17 and Treg cells, as well as their related cytokines in chronic AA patients. Furthermore, the percentages of Th1 and Th17 cells among the H-MSCs decreased significantly, while the percentage Treg cells increased. The Notch/RBP-J/FOXP3/RORγt pathway was involved in modulating the Treg/Th17 balance after MSCs were transfused in vitro. Additionally, the role played by transfused MSCs in regulating the Treg/Th17 balance via the Notch/RBP-J/FOXP3/RORγt pathway was further confirmed in an AA mouse model. In summary, in humans with chronic AA, BMMSCs regulate the Treg/Th17 balance by affecting the Notch/RBP-J/FOXP3/RORγt pathway.

CD56-enriched donor cell infusion after post-transplantation cyclophosphamide for haploidentical transplantation of advanced myeloid malignancies is associated with prompt reconstitution of mature natural killer cells and regulatory T cells with reduced incidence of acute graft versus host disease: A pilot study

We conducted a pilot study on the feasibility of CD56-enriched donor cell infusion after post-transplantation cyclophosphamide (PTCy) for 10 patients with advanced myeloid malignancies undergoing haploidentical peripheral blood stem cell transplantation with cyclosporine alone as graft-versus-host disease (GVHD) prophylaxis and compared the outcome and immune reconstitution with a control group of 20 patients undergoing the same without CD56-enriched donor cell infusion. An early and rapid surge of mature NK cells as well as CD4⁺ T cells and regulatory T cells (Tregs) was noted compared with the control group. KIR of donor phenotype reconstituted as early as day 30 with expression of CD56^dimCD16⁺NKG2A^-KIR⁺ phenotype. None experienced viral or fungal infections, and non-relapse mortality was 10% only. The incidence of grade 2-4 acute GVHD was 50% in the control group with none in the CD56 group (P = 0.01). Only two had de novo chronic GVHD in each group. Relapse occurred in five patients in CD56 group with a median follow-up of 12 months, similar to the control group. Our preliminary data show that CD56⁺ donor cell infusion after PTCy and short-course cyclosporine is feasible with prompt engraftment, rapid reconstitution of CD4⁺T cells, Tregs and NK cells and reduced incidence of acute GVHD.