Extended mycophenolate mofetil and shortened cyclosporine failed to reduce graft-versus-host disease after unrelated hematopoietic cell transplantation with nonmyeloablative conditioning

Disease risk and GVHD biomarkers can stratify patients for risk of relapse and nonrelapse mortality post hematopoietic cell transplant

The graft-versus-leukemia (GVL) effect after allogeneic hematopoietic cell transplant (HCT) can prevent relapse but the risk of severe graft-vs-host disease (GVHD) leads to prolonged intensive immunosuppression and possible blunting of the GVL effect. Strategies to reduce immunosuppression in order to prevent relapse have been offset by increases in severe GVHD and non-relapse mortality (NRM). We recently validated the MAGIC algorithm probability (MAP) that predicts the risk for severe GVHD and NRM in asymptomatic patients using serum biomarkers. In this study we tested whether the MAP could identify patients whose risk for relapse is higher than their risk for severe GVHD and NRM. The multicenter study population (n=1604) was divided into two cohorts: historical (2006–2015, n=702) and current (2015–2017, n=902) with similar non-relapse mortality, relapse, and survival. On day 28 post-HCT, patients who had not developed GVHD (75% of the population) and who possessed a low MAP were at much higher risk for relapse (24%) than severe GVHD and NRM (16% and 9%); this difference was even more pronounced in patients with a high disease risk index (relapse 33%, NRM 9%). Such patients are good candidates to test relapse prevention strategies that might enhance GVL.

Impact of Donor Type in Patients with AML Given Allogeneic Hematopoietic Cell Transplantation After Low-Dose TBI-Based Regimen

Purpose: We assessed the impact of donor type in acute myeloid leukemia (AML) patients transplanted with 2 Gy total body irradiation (TBI)-based nonmyeloablative conditioning regimen.Patients and Methods: Data from 1,715 adult patients, with AML in CR1 or CR2 were included in this retrospective survey.Results: Donors consisted either of HLA-matched sibling donors (MSD, n = 701), 10/10 HLA-matched unrelated donors (MUD, n = 611), HLA-haploidentical donors (haplo, n = 112) or single or double umbilical cord bloods (CBT, n = 291). Chronic graft-versus-host disease (GVHD) was less frequent in CBT (28%) and in haplo (30%) patients than in MSD (50%) and MUD (51%) recipients (P < 0.001). Two-year incidence of relapse was 32%, 30%, 34%, and 34% in MSD, MUD, CBT and haplo patients, respectively (P = 0.7). Two-year overall (OS) and GVHD-free relapse-free survival (GRFS) were 59% and 29% in MSD patients, 56% and 39% in CBT recipients, 53% and 23% in MUD recipients, and 43% and 37% in haplo patients, respectively. In multivariate analyses, MUD patients had lower GRFS than MSD patients beyond day 100 (HR 1.3, P = 0.001) while CBT was associated with a better GRFS than MSD beyond day 100 (HR 0.6, P = 0.002).Conclusions: In this large cohort of AML patients transplanted following low-dose TBI-based conditioning, the relapse incidence was not affected by donor type suggesting that the intensity of GVL effects might be comparable with these four transplant approaches. Furthermore, CBT was associated with better GRFS beyond day 100 than MSD while the opposite was observed for MUD. Clin Cancer Res; 24(12); 2794-803. ©2018 AACR.

Novel approaches for preventing acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

INTRODUCTION

Allogeneic hematopoietic stem cell transplantation (alloHSCT) offers potential curative treatment for a wide range of malignant and nonmalignant hematological disorders. However, its success may be limited by post-transplant acute graft-versus-host disease (aGVHD), a systemic syndrome in which donor's immune cells attack healthy tissues in the immunocompromised host. aGVHD is one of the main causes of morbidity and mortality after alloHSCT. Despite standard GVHD prophylaxis regimens, aGVHD still develops in approximately 40-60% of alloHSCT recipients.

AREAS COVERED

In this review, after a brief summary of current knowledge on the pathogenesis of aGVHD, the authors review the current combination of a calcineurin inhibitor with an antimetabolite with or without added anti-thymocyte globulin (ATG) and emerging strategies for GVHD prevention.

EXPERT OPINION

A new understanding of the involvement of cytokines, intracellular signaling pathways, epigenetics and immunoregulatory cells in GVHD pathogenesis will lead to new standards for aGVHD prophylaxis allowing better prevention of severe aGVHD without affecting graft-versus-tumor effects.

Non-myeloablative allogeneic hematopoietic cell transplantation following fludarabine plus 2 Gy TBI or ATG plus 8 Gy TLI: a phase II randomized study from the Belgian Hematological Society

BACKGROUND

Few studies thus far have compared head-to-head different non-myelooablative conditioning regimens for allogeneic hematopoietic cell transplantation (allo-HCT).

METHODS

Here, we report the results of a phase II multicenter randomized study comparing non-myeloablative allo-HCT from HLA-identical siblings (n = 54) or from 10/10 HLA-matched unrelated donors (n = 40) with either fludarabine plus 2 Gy total body irradiation (Flu-TBI arm; n = 49) or 8 Gy TLI + anti-thymocyte globulin (TLI-ATG arm; n = 45) conditioning.

RESULTS

The 180-day cumulative incidences of grade II-IV acute GVHD (primary endpoint) were 12.2% versus 8.9% in Flu-TBI and TLI-ATG patients, respectively (P = 0.5). Two-year cumulative incidences of moderate/severe chronic GVHD were 40.8% versus 17.8% in Flu-TBI and TLI-ATG patients, respectively (P = 0.017). Five Flu-TBI patients and 10 TLI-ATG patients received pre-emptive DLI for low donor chimerism levels, while 1 Flu-TBI patient and 5 TLI-ATG patients (including 2 patients given prior pre-emptive DLIs) received a second HCT for poor graft function, graft rejection, or disease progression. Four-year cumulative incidences of relapse/progression were 22% and 50% in Flu-TBI and TLI-ATG patients, respectively (P = 0.017). Four-year cumulative incidences of nonrelapse mortality were 24% and 13% in Flu-TBI and TLI-ATG patients, respectively (P = 0.5). Finally, 4-year overall (OS) and progression-free survivals (PFS) were 53% and 54%, respectively, in the Flu-TBI arm, versus 54% (P = 0.9) and 37% (P = 0.12), respectively, in the TLI-ATG arm.

CONCLUSIONS

In comparison to patients included in the Flu-TBI arm, patients included in the TLI-ATG arm had lower incidence of chronic GVHD, higher incidence of relapse and similar OS.

TRIAL REGISTRATION

The study was registered on ClinicalTrial.gov ( NCT00603954 ) and EUDRACT (2010-024297-19) .

A randomized phase II trial of tacrolimus, mycophenolate mofetil and sirolimus after non-myeloablative unrelated donor transplantation

The study is a randomized phase II trial investigating graft-versus-host disease prophylaxis after non-myeloablative (90 mg/m(2) fludarabine and 2 Gy total body irradiation) human leukocyte antigen matched unrelated donor transplantation. Patients were randomized as follows: arm 1 - tacrolimus 180 days and mycophenolate mofetil 95 days (n=69); arm 2 - tacrolimus 150 days and mycophenolate mofetil 180 days (n=71); arm 3 - tacrolimus 150 days, mycophenolate mofetil 180 days and sirolimus 80 days (n=68). All patients had sustained engraftment. Grade II-IV acute graft-versus-host disease rates in the 3 arms were 64%, 48% and 47% at Day 150, respectively (arm 3 vs. arm 1 (hazard ratio 0.62; P=0.04). Owing to the decreased incidence of acute graft-versus-host disease, systemic steroid use was lower at Day 150 in arm 3 (32% vs. 55% in arm 1 and 49% in arm 2; overall P=0.009 by hazard ratio analysis). The Day 150 incidence of cytomegalovirus reactivation was lower in arm 3 (arm 1, 54%; arm 2, 47%; arm 3, 22%; overall P=0.002 by hazard ratio analysis). Non-relapse mortality was comparable in the three arms at two years (arm 1, 26%; arm 2, 23%; arm 3, 18%). Toxicity rates and other outcome measures were similar between the three arms. The addition of sirolimus to tacrolimus and mycophenolate mofetil is safe and associated with lower incidence of acute graft-versus-host disease and cytomegalovirus reactivation. (clinicaltrials.gov identifier: 00105001).

Nonrelapse mortality and mycophenolic acid exposure in nonmyeloablative hematopoietic cell transplantation

We evaluated the pharmacodynamic relationships between mycophenolic acid (MPA), the active metabolite of mycophenolate mofetil (MMF), and outcomes in 308 patients after nonmyeloablative hematopoietic cell transplantation. Patients were conditioned with total body irradiation ± fludarabine, received grafts from HLA-matched related (n = 132) or unrelated (n = 176) donors, and received postgrafting immunosuppression with MMF and a calcineurin inhibitor. Total and unbound MPA pharmacokinetics were determined to day 25; maximum a posteriori Bayesian estimators were used to estimate total MPA concentration at steady state (Css). Rejection occurred in 9 patients, 8 of whom had a total MPA Css less than 3 μg/mL. In patients receiving a related donor graft, MPA Css was not associated with clinical outcomes. In patients receiving an unrelated donor graft, low total MPA Css was associated with increased grades III to IV acute graft-versus-host disease and increased nonrelapse mortality but not with day 28 T cell chimerism, disease relapse, cytomegalovirus reactivation, or overall survival. We conclude that higher initial oral MMF doses and subsequent targeting of total MPA Css to greater than 2.96 μg/mL could lower grades III to IV acute graft-versus-host disease and nonrelapse mortality in patients receiving an unrelated donor graft.

Mesenchymal stromal cells: a new tool against graft-versus-host disease?

Mesenchymal stromal cells (MSCs) represent a heterogeneous subset of multipotent cells that can be isolated from several tissues including bone marrow and fat. MSCs exhibit immunomodulatory and anti-inflammatory properties that prompted their clinical use as prevention and/or treatment for severe graft-versus-host disease (GVHD). Although a number of phase I-II studies have suggested that MSC infusion was safe and might be effective for preventing or treating acute GVHD, definitive proof of their efficacy remains lacking thus far. Multicenter randomized studies are ongoing to more precisely assess the impact of MSC infusion on GVHD prevention/treatment, whereas further research is performed in vitro and in animal models with the aims of determining the best way to expand MSCs ex vivo as well as the most efficient dose and schedule of MSCs administration. After introducing GVHD, MSC biology, and results of MSC infusion in animal models of allogeneic hematopoietic cell transplantation, this article reviews the results of the first clinical trials investigating the use of MSC infusion as prevention or treatment of GVHD.

Intensification of GVHD prophylaxis with low-dose ATG-F before allogeneic PBSC transplantation from HLA-identical siblings in adult patients with hematological malignancies: results from a retrospective analysis

Several studies have shown that chronic GVHD (cGVHD) is more frequent in patients receiving transplants from PBSC than in those receiving BM. In the setting of PBSC-unrelated transplants, the addition of anti-T-cell globulin (ATG) has shown a significant decrease in incidence/severity of cGVHD, without an increase in relapses or infections. However, no prospective data are yet available in the sibling setting. We retrospectively analyzed the effects of intensification of standard GVHD prophylaxis (CsA+MTX) by the addition of low-dose ATG in 245 patients receiving a transplant from HLA-identical sibling. From 1996 to 2001, patients received PBSC as the preferred source (group 2), and then ATG was added before transplant (group 3) because of a high cGVHD rate. Patients receiving BM in the same time period were analyzed as a control group (group 1). The incidence of grade III-IV acute GVHD and cGVHD was not significantly different in the three groups, but extensive cGVHD was highest in group 2 (38%) compared with group 3 (21%) or group 1 (28%; P=0.03). OS, TRM and time to relapse/progression were similar in the three groups. Our analysis shows that adding ATG to PBSC sibling allogeneic transplants can lower cGVHD, without an increase of relapse. Further prospective studies are needed to confirm these findings.

Cotransplantation of mesenchymal stem cells might prevent death from graft-versus-host disease (GVHD) without abrogating graft-versus-tumor effects after HLA-mismatched allogeneic transplantation following nonmyeloablative conditioning

Recent studies have suggested that coinfusion of mesenchymal stem cells (MSCs) the day of hematopoietic cell transplantation (HCT) might promote engraftment and prevent graft-versus-host disease (GVHD) after myeloablative allogeneic HCT. This prompted us to investigate in a pilot study whether MSC infusion before HCT could allow nonmyeloablative (NMA) HCT (a transplant strategy based nearly exclusively on graft-versus-tumor effects for tumor eradication) from HLA-mismatched donors to be performed safely. Twenty patients with hematologic malignancies were given MSCs from third party unrelated donors 30-120 minutes before peripheral blood stem cells (PBSCs) from HLA-mismatched unrelated donors, after conditioning with 2 Gy total body irradiation (TBI) and fludarabine. The primary endpoint was safety, defined as a 100-day incidence of nonrelapse mortality (NRM) <35%. One patient had primary graft rejection, whereas the remaining 19 patients had sustained engraftment. The 100-day cumulative incidence of grade II-IV acute GVHD (aGVHD) was 35%, whereas 65% of the patients experienced moderate/severe chronic GVHD (cGVHD). One-year NRM (10%), relapse (30%), overall survival (OS) (80%) and progression-free survival (PFS) (60%), and 1-year incidence of death from GVHD or infection with GVHD (10%) were encouraging. These figures compare favorably with those observed in a historic group of 16 patients given HLA-mismatched PBSCs (but no MSCs) after NMA conditioning, which had a 1-year incidence of NRM of 37% (P = .02), a 1-year incidence of relapse of 25% (NS), a 1-year OS and PFS of 44% (P = .02), and 38% (P = .1), respectively, and a 1-year rate of death from GVHD or infection with GVHD of 31% (P = .04). In conclusion, our data suggest that HLA-mismatched NMA HCT with MSC coinfusion appeared to be safe.

Elevations of tumor necrosis factor receptor 1 at day 7 and acute graft-versus-host disease after allogeneic hematopoietic cell transplantation with nonmyeloablative conditioning

Acute GVHD has remained a significant cause of nonrelapse mortality after allogeneic hematopoietic cell transplantation (HCT) with nonmyeloablative conditioning. The role of TNF-alpha in the biology of acute GVHD after nonmyeloablative conditioning has not been studied thus far. Here, we measured TNF receptor 1 (TNFR1) as a surrogate marker for TNF-alpha in 106 patients before the start of the conditioning regimen (baseline) and 7 days after allogeneic HCT with nonmyeloablative conditioning. The nonmyeloablative regimen consisted of 2 Gy TBI alone (n=15), 2 Gy TBI plus fludarabine 90 mg/m2 (n=73), or 4 Gy TBI plus fludarabine 90 mg/m2 (n=18). TNFR1 levels increased significantly from baseline to day 7 after nonmyeloablative HCT (P<0.0001). Patients conditioned with 4 Gy TBI had higher TNFR1 day 7/baseline ratio than those conditioned with 2 Gy TBI (median 1.65 versus 1.25; P=0.01). In a multivariate Cox model, high TNFR1 day7/baseline ratio was associated with grades II-IV (HR=2.2, P=0.01) and grades III-IV (HR=2.9, P=0.007) acute GVHD, but had no impact on overall survival (P=0.8). In summary, our data suggest that nonmyeloablative conditioning induces the generation of TNF-alpha, and that the magnitude of TNF-alpha generation depends on the conditioning intensity (2 Gy versus 4 Gy TBI). Further, assessment of TNFR1 levels before and on day 7 after nonmyeloablative HCT provided useful information on subsequent risk of experiencing acute GVHD.

An age-dependent pharmacokinetic study of intravenous and oral mycophenolate mofetil in combination with tacrolimus for GVHD prophylaxis in pediatric allogeneic stem cell transplantation recipients

Acute graft-versus-host disease (aGVHD) still remains a major limiting factor following allogeneic stem cell transplantation (AlloSCT) in pediatric recipients. Mycophenolate mofetil (MMF), an uncompetitive selective inhibitor of inosine monophosphate dehydrogenase, is a new immunosuppressant agent without major mucosal, hepatic, or renal toxicity compared to other prophylactic aGVHD immunosuppressant drugs. Although there has been an extensive pharmacokinetic (PK) experience with MMF administration following solid organ transplantation in children, there is a paucity of PK data following its use in pediatric AlloSCT recipients. We investigated the safety and PK of MMF as GVHD prophylaxis following intravenous (i.v.) and oral (p.o.) administration (900 mg/m(2) every 6 hours) in conjunction with tacrolimus, after myeloablative (MA) and nonmyeloablative (NMA) conditioning and AlloSCT in 3 distinct age groups of pediatric AlloSCT recipients (0-6 years, 6-12 years, and 12-16 years). Mycophenolic acid (MPA) in plasma samples was measured either by high-performance liquid chromatography (HPLC) or liquid chromatography/mass spectrometry (LC/MS/MS) as we have previously described. Plasma samples were obtained at baseline and at 0.5, 1, 2, 3, 4, and 6 hours after i.v. dosing on days +1, +7, +14, and at 2 time points between day +45 and +100 after p.o. administration post AlloSCT. MPA PK analysis included AUC (0-6 hours), C(max), T(max), C(ss), V(ss), C trough (C(0)), CL, and T((1/2).) Thirty-eight patients, with a median age of 8 years (0.33-16 years), 20/18 M:F ratio, 21/17 malignant/nonmalignant disease, 17/21 MA: NMA conditioning, 16 of 22 related/unrelated allografts. Median time to myeloid and platelet engraftment was 18 and 31 days, respectively. Mean donor chimerism on day +60 and +100 was 83% and 90%, respectively. Probability of developing aGVHD grade II-IV and extensive chronic GVHD (cGVHD) was 54% and 34%, respectively. There was significant intra- and interpatient MMF PK variability. There was a significant increase in i.v. MPA area under the curve (AUC)(0-6 hour) and C(max) (P < .0003) and a significant decrease in CL(ss) (P < .002) and V(ss) (P < .001) on day +14 versus day +7. Children <12 years of age had a significant increase in i.v. MPA T(max) (P = .01), V(ss) (P = .028), and CL(ss) (P < .001) compared to the older age group. There was a trend in increased i.v. MPA CL(ss) following MA versus NMA conditioning (P < .054); i.v. and p.o. MMF administration (900 mg/m(2) every 6 hours) in combination with tacrolimus was well tolerated in pediatric AlloSCT recipients. There was a significant increase in MPA exposure on day +14 versus day +7, suggesting improved enterohepatic recirculation at day +14 post-AlloSCT. Children <12 years of age appear to have a significantly different MPA PK profile compared to older children and adolescents and may require more frequent dosing.

What is the role for donor natural killer cells after nonmyeloablative conditioning?

We investigated the impacts of the tempo of early (days 14, 28, and 42) donor T cell and natural killer (NK) cell engraftment, missing recipient killer cell immunoglobulin-like receptor (KIR) ligands, and numbers of donor inhibitory and activating KIR genes on hematopoietic cell transplantation (HCT) outcomes in 282 patients with hematologic malignancies given nonmyeloablative conditioning. Modeling chimerism levels as a continuous linear variable, we found that high early donor T cell chimerism was significantly associated with acute graft-versus-host disease (aGVHD) (P = .01), whereas high donor NK cell chimerism levels had no such association (P = .38). Conversely, high donor NK cell chimerism levels were significantly associated with low relapse risk (P = .0009), whereas no significant association was seen with high donor T cell chimerism (P = .10). The qualitative associations between donor T cell and NK cell chimerism levels and GVHD and relapse did not change after adjustment for the presence of recipient KIR ligands or numbers of donor inhibitory or activating KIR genes. Our data indicate that prompt engraftment of donor NK cells correlated with lessened risks of relapse, but not with GVHD, whereas the converse was true for T cells.

Feasibility of conditioning with thymoglobulin and reduced intensity TBI to reduce acute GVHD in recipients of allogeneic SCT

Murine studies using anti-T-cell antibodies for conditioning in allogeneic SCT demonstrate engraftment with low rates of GVHD. On the basis of this preclinical model, we conditioned 30 patients with advanced hematologic malignancies with rabbit antithymocyte globulin (ATG) and TBI, to reduce rates of fatal acute GVHD. Patients were enrolled in two sequential groups: cohort 1 received ATG 10 mg/kg in divided doses (days -4 to -1)+200 cGy TBI (n=16), and cohort 2 received ATG (days -10 to -7)+450 cGy TBI (n=14). Median donor blood chimerism for the combined group was 94, 93 and 93% in the first, second and third months after transplant. Only three developed grade II acute GVHD despite 43% of patients receiving unrelated donor transplants. One-year survival was 71+/-11 and 54+/-14%, respectively, in recipients of related and unrelated donor SCT. Donor lymphocyte infusions were needed in 12 patients for the management of relapse and for mixed donor-recipient chimerism in 4 patients. We conclude that 10 mg/kg ATG and TBI allows engraftment with a low risk of acute GVHD; however, further dose optimization of ATG is required to achieve a balance between GVHD and disease relapse.