Effect of FK506 on donor T-cell functions that are responsible for graft-versus-host disease and graft-versus-leukemia effect

CYP3A5 influences oral tacrolimus pharmacokinetics and timing of acute kidney injury following allogeneic hematopoietic stem cell transplantation

Introduction: Polymorphisms in genes responsible for the metabolism and transport of tacrolimus have been demonstrated to influence clinical outcomes for patients following allogeneic hematologic stem cell transplant (allo-HSCT). However, the clinical impact of germline polymorphisms specifically for oral formulations of tacrolimus is not fully described. Methods: To investigate the clinical impact of genetic polymorphisms in CYP3A4, CYP3A5, and ABCB1 on oral tacrolimus pharmacokinetics and clinical outcomes, we prospectively enrolled 103 adult patients receiving oral tacrolimus for the prevention of graft-versus-host disease (GVHD) following allo-HSCT. Patients were followed in the inpatient and outpatient phase of care for the first 100 days of tacrolimus therapy. Patients were genotyped for CYP3A5 *3 (rs776746), CYP3A4 *1B (rs2740574), ABCB1 exon 12 (rs1128503), ABCB1 exon 21 (rs2032582), ABCB1 exon 26 (rs1045642). Results: Expression of CYP3A5 *1 was highly correlated with tacrolimus pharmacokinetics in the inpatient phase of care (p < 0.001) and throughout the entirety of the study period (p < 0.001). Additionally, Expression of CYP3A5 *1 was associated with decreased risk of developing AKI as an inpatient (p = 0.06). Variants in ABCB1 were not associated with tacrolimus pharmacokinetics in this study. We were unable to discern an independent effect of CYP3A4 *1B or *22 in this population. Conclusion: Expression of CYP3A5 *1 is highly influential on the pharmacokinetics and clinical outcomes for patients receiving oral tacrolimus as GVHD prophylaxis following allo-HSCT.

Inhibition of inositol kinase B controls acute and chronic graft-versus-host disease

T-cell activation releases inositol 1,4,5-trisphosphate (IP3), inducing cytoplasmic calcium (Ca2+) influx. In turn, inositol 1,4,5-trisphosphate 3-kinase B (Itpkb) phosphorylates IP3 to negatively regulate and thereby tightly control Ca2+ fluxes that are essential for mature T-cell activation and differentiation and protection from cell death. Itpkb pathway inhibition increases intracellular Ca2+, induces apoptosis of activated T cells, and can control T-cell-mediated autoimmunity. In this study, we employed genetic and pharmacological approaches to inhibit Itpkb signaling as a means of controlling graft-versus-host disease (GVHD). Murine-induced, Itpkb-deleted (Itpkb-/-) T cells attenuated acute GVHD in 2 models without eliminating A20-luciferase B-cell lymphoma graft-versus-leukemia (GVL). A highly potent, selective inhibitor, GNF362, ameliorated acute GVHD without impairing GVL against 2 acute myeloid leukemia lines (MLL-AF9-eGFP and C1498-luciferase). Compared with FK506, GNF362 more selectively deleted donor alloreactive vs nominal antigen-responsive T cells. Consistent with these data and as compared with FK506, GNF362 had favorable acute GVHD and GVL properties against MLL-AF9-eGFP cells. In chronic GVHD preclinical models that have a pathophysiology distinct from acute GVHD, Itpkb-/- donor T cells reduced active chronic GVHD in a multiorgan system model of bronchiolitis obliterans (BO), driven by germinal center reactions and resulting in target organ fibrosis. GNF362 treatment reduced active chronic GVHD in both BO and scleroderma models. Thus, intact Itpkb signaling is essential to drive acute GVHD pathogenesis and sustain active chronic GVHD, pointing toward a novel clinical application to prevent acute or treat chronic GVHD.

Tacrolimus prevents murine cerebral malaria

Tacrolimus and mycophenolate mofetil are immunosuppressants frequently used in human organ transplantation. Tacrolimus is also reported to inhibit Plasmodium falciparum growth in vitro. Here, we report that tacrolimus prevented the death from cerebral malaria of Plasmodium berghei ANKA-infected C57BL/6J mice, but not their death from malaria due to the high parasitaemia and severe anaemia. The mycophenolate mofetil-treated mice showed higher mortality from cerebral malaria and succumbed to malaria earlier than tacrolimus-treated littermates. Tacrolimus attenuated the infiltration of mononuclear cells including pathogenic CD8⁺ T cells into the brain. It appears to prevent murine cerebral malaria through the inhibition of cerebral infiltration of CD8⁺ T cells.

The MEK inhibitor trametinib separates murine graft-versus-host disease from graft-versus-tumor effects

The efficacy of allogeneic hematopoietic stem cell transplantation for hematologic malignancies is limited by the difficulty in suppressing graft-versus-host disease (GVHD) without compromising graft-versus-tumor (GVT) effects. We previously showed that RAS/MEK/ERK signaling depends on memory differentiation in human T cells, which confers susceptibility to selective inhibition of naive T cells. Actually, antineoplastic MEK inhibitors selectively suppress alloreactive T cells, sparing virus-specific T cells in vitro. Here, we show that trametinib, a MEK inhibitor clinically approved for melanoma, suppresses GVHD safely without affecting GVT effects in vivo. Trametinib prolonged survival of GVHD mice and attenuated GVHD symptoms and pathology in the gut and skin. It inhibited ERK1/2 phosphorylation and expansion of donor T cells, sparing Tregs and B cells. Although high-dose trametinib inhibited myeloid cell engraftment, low-dose trametinib suppressed GVHD without severe adverse events. Notably, trametinib facilitated the survival of mice transplanted with allogeneic T cells and P815 tumor cells with no residual P815 cells observed in the livers and spleens, whereas tacrolimus resulted in P815 expansion. These results confirm that trametinib selectively suppresses GVHD-inducing T cells while sparing antitumor T cells in vivo, which makes it a promising candidate for translational studies aimed at preventing or treating GVHD.

Outcomes of Allogeneic Hematopoietic Cell Transplantation in Children and Young Adults with Chronic Myeloid Leukemia: A CIBMTR Cohort Analysis

Chronic myeloid leukemia (CML) in children and young adults is uncommon. Young patients have long life expectancies and low morbidity with hematopoietic cell transplantation (HCT). Prolonged tyrosine kinase inhibitor (TKI) use may cause significant morbidity. In addition, indication for HCT in patients in the first chronic phase is not established. We hence retrospectively evaluated outcomes in 449 CML patients with early disease receiving myeloablative HCT reported to the CIBMTR. We analyzed various factors affecting outcome, specifically the effect of age and pre-HCT TKI in pediatric patients (age < 18 years, n = 177) and young adults (age 18 to 29 years, n = 272) with the goal of identifying prognostic factors. Post-HCT probability rates of 5-year overall survival (OS) and leukemia-free survival (LFS) were 75% and 59%, respectively. Rates of OS and LFS were 76% and 57% in <18-year and 74% and 60% in 18- to 29-year group, respectively, by univariate analysis (P = .1 and = .6). Five-year rates of OS for HLA matched sibling donor (MSD) and bone marrow (BM) stem cell source were 83% and 80%, respectively. In multivariate analysis there was no effect of age (<18 versus 18 to 29) or pre-HCT TKI therapy on OS, LFS, transplant related mortality, or relapse. Favorable factors for OS were MSD (P < .001) and recent HCT (2003 to 2010; P = .04). LFS was superior with MSD (P < .001), BM as graft source (P = .001), and performance scores > 90 (P = .03) compared with unrelated or mismatched peripheral blood stem cells donors and recipients with lower performance scores. Older age was associated with increased incidence of chronic graft-versus-host disease (P = .0002). In the current era, HCT outcomes are similar in young patients and children with early CML, and best outcomes are achieved with BM grafts and MSD.

Cellular therapy following allogeneic stem-cell transplantation

Allogeneic hematopoietic stem-cell transplantation (HSCT) is the most effective approach for many patients with hematologic malignancies. Unfortunately, relapse remains the most common cause of death after allogeneic HSCT, and the prognosis of relapsed disease is poor for most patients. Induction of a graft-versus-leukemia (GVL), or graft-versus-tumor, effect through the use of donor leukocyte infusion (DLI), or donor lymphocyte infusion, has been remarkably successful for relapsed chronic myelogenous leukemia. Unfortunately, response to DLI in other hematologic malignancies is much less common and depends on many factors including histology, pace and extent of relapse, and time from HSCT to relapse. Furthermore, graft-versus-host disease (GVHD) is common after DLI and often limits successful immunotherapy. Ultimately, manipulations to minimize GVHD while preserving or enhancing GVL are necessary to improve outcomes for relapse after allogeneic HSCT.

Pre-engraftment graft-versus-host disease after allogeneic hematopoietic cell transplantation for acute leukemia

OBJECTIVES

Acute graft-versus-host disease (GVHD) usually occurs with neutrophil engraftment following allogeneic hematopoietic cell transplantation (HCT), but it can also occur before engraftment. We intended to analyze the effects of timing of acute GVHD on leukemia relapse and mortality.

METHODS

The outcomes of pre- and postengraftment GVHD were investigated in 384 patients who underwent allogeneic HCT for acute leukemia.

RESULTS

Acute GVHD occurred in 100 patients, pre-engraftment in 22 and postengraftment in 78. Compared with postengraftment GVHD, pre-engraftment GVHD was more severe, as assessed by overall grade, with more frequent and more severe skin involvement and higher incidences of non-infectious fever, diarrhea, hepatic dysfunction, renal insufficiency, and weight gain. Compared with patients without acute GVHD, those with postengraftment GVHD had lower cumulative incidence of relapse [CIR; hazard ratio (HR), 0.470; P=0.006] and higher cumulative incidence of non-relapse mortality (CINRM; HR, 2.568; P<0.001), while those with pre-engraftment GVHD had similar CIR (HR, 0.815; P=0.059) and higher CINRM (HR, 2.872; P=0.036). Overall survival of patients with pre-engraftment GVHD was lower than that of those without acute GVHD (HR, 1.976; P=0.017), which was similar to that of those with postengraftment GVHD (HR, 0.969; P=0.878). Separate analyses of the effects of timing of acute GVHD on post-transplant outcomes in patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) showed similar trends.

CONCLUSION

Pre-engraftment GVHD might be a 'cytokine storm' type syndrome rather than 'real' GVHD, indicating the need for separate analyses of pre- and postengraftment GVHD in future trials.

NCI First International Workshop on the Biology, Prevention, and Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation: Report from the Committee on Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation

Relapse is a major cause of treatment failure after allogeneic hematopoietic stem cell transplantation (alloHSCT). Treatment options for relapse have been inadequate, and the majority of patients ultimately die of their disease. There is no standard approach to treating relapse after alloHSCT. Withdrawal of immune suppression and donor lymphocyte infusions are commonly used for all diseases; although these interventions are remarkably effective for relapsed chronic myelogenous leukemia, they have limited efficacy in other hematologic malignancies. Conventional and novel chemotherapy, monoclonal antibody therapy, targeted therapies, and second transplants have been utilized in a variety of relapsed diseases, but reports on these therapies are generally anecdotal and retrospective. As such, there is an immediate need for well-designed, disease-specific trials for treatment of relapse after alloHSCT. This report summarizes current treatment options under investigation for relapse after alloHSCT in a disease-specific manner. In addition, recommendations are provided for specific areas of research necessary in the treatment of relapse after alloHSCT.

Allogeneic bone marrow transplantation for hepatocellular carcinoma: hepatocyte growth factor suppresses graft-vs.-host disease

Allogeneic bone-marrow transplantation (BMT) can induce a powerful graft-vs.-tumor (GVT) effect not only on hematological malignancies but also on solid tumors. However, graft-vs.-host disease (GVHD) is a major complication of allogeneic BMT. We assessed GVT effect on hepatocellular carcinoma (HCC) and the effects of hepatocyte growth factor (HGF) gene transduction on GVHD in HCC transplanted mice. (C57BL/6 x C3H/HeJ)F(1)(B6C3F1, H-2(bxk)) mice were used as recipients and C3H/HeJ(H-2(k)) mice were used as donors. Hepa1-a (a C57L mouse-derived hepatoma cell, H-2(b)) was subcutaneously injected into the recipient mice. Tumor bearing mice were treated in the following ways: group 1, no treatment; group 2, total body irradiation (TBI); group 3, TBI and BMT; group 4, TBI and BMT with empty vector; group 5, TBI and BMT with HGF gene transduction; group 6, TBI and BMT with administration of FK506, a representative immunosuppressive agent. Acute GVHD was assessed by histological examination of the liver, small intestines, and large intestines. Tumor growth was markedly suppressed in mice that received an allogeneic BMT. Donor-derived CD8(+) T cells had infiltrated into the tumor, and cytotoxic CD8(+) T cells against HCC were present. However, among the four groups that received a BMT, this suppressive effect was weaker in group 6 compared with the other three groups (groups 3, 4, and 5). HGF gene transduction improved GVHD while preserving the GVT effects. Allogeneic BMT markedly suppresses the growth of HCC. Simultaneous HGF gene transfer can suppress GVHD while preserving the GVT effect.

Inhibition of donor-derived T cells trafficking into target organs by FTY720 during acute graft-versus-host disease in small bowel transplantation

In small bowel transplantation (SBTx), graft-versus-host disease (GVHD) is mediated by donor-derived T cells recognizing host major histocompatibility complex (MHC) alloantigens, and represents an important immunological event influencing life in experimental and clinical situations. We evaluated the possibility that a new sphingosine 1-phosphate receptor agonist, FTY720, could diminish GVHD in a rat SBTx model through traffic alteration of donor-derived T cells in target organs. Heterotopic SBTx was performed using a parent (WF)-into-F(1) (WF x ACI) rat combination. Recipient survival, body weight, histopathology, donor-derived T cell subpopulation and cytokine production were compared with untreated controls. FTY720 inhibited lethality and histopathological changes in target organs when administered at 0.5 mg/kg, possibly due to sequestration of donor-derived T cells in the intestinal graft. FTY720 caused a significant reduction in donor T cell numbers in target organs by promoting these cells to home into donor, but not recipient, secondary lymphoid tissues. FTY720 significantly decreased production of interferon (IFN)-gamma in target organs. These findings indicate that FTY720 effectively reduced recirculation of activated donor-derived T cells and recruitment to target organs in GVHD, and was also associated with down-regulated IFN-gamma production. These properties may offer the potential to treat ongoing GVHD in SBTx.

Intervention of MAdCAM-1 or fractalkine alleviates graft-versus-host reaction associated intestinal injury while preserving graft-versus-tumor effects

Coincidence of the beneficial graft-vs.-tumor (GVT) effects and the detrimental graft-vs.-host disease (GVHD) remains the major obstacle against the widespread use of allogeneic bone marrow transplantation (BMT) as tumor immunotherapy. We here demonstrate that intervention of MAdCAM-1 (mucosal vascular addressin cell adhesion molecule-1) or fractalkine/CX3CL1 after the expansion of allo-reactive donor CD8 T cells selectively inhibits the recruitment of effector donor CD8 T cells to the intestine and alleviates the graft-vs.-host reaction (GVHR) associated intestinal injury without impairing GVT effects. In a nonirradiated acute GVHD model, donor CD8 T cells up-regulate the expression of intestinal homing receptor alpha4beta7 and chemokine receptors CXCR6 and CX3CR1, as they differentiate into effector cells and subsequently infiltrate into the intestine. Administration of anti-MAdCAM-1 antibody or anti-fractalkine antibody, even after the expansion of alloreactive donor CD8 T cells, selectively reduced the intestine-infiltrating donor CD8 T cells and the intestinal crypt cell apoptosis without affecting the induction of donor derived anti-host CTL or the infiltration of donor CD8 T cells in the hepatic tumor. Moreover, in a clinically relevant GVHD model with myeloablative conditioning, these antibodies significantly improved the survival and loss of weight without impairing the beneficial GVT effects. Thus, interruption of alpha4beta7-MAdCAM-1 or CX3CR1-fractalkine interactions in the late phase of GVHD would be a novel therapeutic approach for the separation of GVT effects from GVHR-associated intestinal injury.

CCR2 is required for CD8-induced graft-versus-host disease

Graft-versus-host disease (GVHD) is a major complication of allogeneic hematopoietic stem cell transplantation (HSCT). Migration of donor-derived T cells into GVHD target organs plays a critical role in the development of GVHD and chemokines and their receptors are important molecules involved in this process. Here, we demonstrate in murine bone marrow transplantation models that the expression of the inflammatory CC chemokine receptor 2 (CCR2) on donor-derived CD8+ T cells is relevant for the control of CD8+ T-cell migration and development of GVHD. Recipients of CCR2-deficient (CCR2-/-) CD8+ T cells developed less damage of gut and liver than recipients of wild-type CD8+ T cells, which correlated with a reduction in overall GVHD morbidity and mortality. Assessment of donor CD8+ T-cell target organ infiltration revealed that CCR2-/- CD8+ T cells have an intrinsic migratory defect to the gut and liver. Other causes for the reduction in GVHD could be excluded, as alloreactive proliferation, activation, IFN-gamma production and cytotoxicity of CCR2-/- CD8+ T cells were intact. Interestingly, the graft-versus-tumor effect mediated by CCR2-/- CD8+ T cells was preserved, which suggests that interference with T-cell migration by blockade of CCR2 signaling can separate GVHD from GVT activity.

Recent advances in the treatment of graft-versus-host disease

Graft-versus-host disease (GVHD) is a lethal complication of allogeneic hematopoietic stem cell transplantation (HSCT) where immunocompetent donor T cells attack the genetically disparate host cells. The predominant symptoms of acute GVHD occur in the skin, liver, and intestine. Induction of acute GVHD can be divided into three phases: recipient conditioning, donor T cell activation, and effector cell-mediated GVHD. Chronic GVHD usually appears up to 100 days after HSCT and is characterized by symptoms similar to those observed for autoimmune disease. It is possible that chronic GVHD is the result of autoreactive T cells that escaped negative selection due to damage to the thymus from conditioning regimens, acute GVHD, and/or age related atrophy. Recent advances in the understanding of the basic mechanisms involved in GVHD pathophysiology have led to new strategies designed to block GVHD. This review focuses on recent developments in the treatment of GVHD, including insights gained from our own experimental studies.