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

An Overview of Autophagy in Hematopoietic Stem Cell Transplantation

Autophagy is a fundamental homeostatic process crucial for cellular adaptation in response to metabolic stress. Autophagy exerts its effect through degrading intracellular components and recycling them to produce macromolecular precursors and energy. This physiological process contributes to cellular development, maintenance of cellular/tissue homeostasis, immune system regulation, and human disease. Allogeneic hematopoietic stem cell transplantation (HSCT) is the only preferred therapy for most bone marrow-derived cancers. Unfortunately, HSCT can result in several serious and sometimes untreatable conditions due to graft-versus-host disease (GVHD), graft failure, and infection. These are the major cause of morbidity and mortality in patients receiving the transplant. During the last decade, autophagy has gained a considerable understanding of its role in various diseases and cellular processes. In light of recent research, it has been confirmed that autophagy plays a crucial role in the survival and function of hematopoietic stem cells (HSCs), T-cell differentiation, antigen presentation, and responsiveness to cytokine stimulation. Despite the importance of these events to HSCT, the role of autophagy in HSCT as a whole remains relatively ambiguous. As a result of the growing use of autophagy-modulating agents in the clinic, it is imperative to understand how autophagy functions in allogeneic HSCT. The purpose of this literature review is to elucidate the established and implicated roles of autophagy in HSCT, identifying this pathway as a potential therapeutic target for improving transplant outcomes.

The Addition of Sirolimus to GVHD Prophylaxis After Allogeneic Hematopoietic Stem Cell Transplantation: A Meta-Analysis of Efficacy and Safety

Objective

The objective of this study was to evaluate the safety and efficacy of sirolimus (SRL) in the prevention of graft-versus-host disease (GVHD) in recipients following allogeneic hematopoietic stem cell transplantation (allo-HSCT).

Methods

Randomized controlled trials (RCTs) evaluating the safety and efficacy of SRL-based prophylaxis regimens in patients receiving allo-HSCT were obtained from PubMed, Embase, and the Cochrane database. Following specific inclusion and exclusion criteria, studies were selected and screened by two independent reviewers who subsequently extracted the study data. The Cochrane risk bias evaluation tool was used for quality evaluation, and RevMan 5.3 software was used for statistical analysis comparing the effects of SRL-based and non–SRL-based regimens on acute GVHD, chronic GVHD, overall survival (OS), relapse rate, non-relapse mortality (NRM), thrombotic microangiopathy (TMA), and veno-occlusive disease (VOD).

Results

Seven studies were included in this meta-analysis, with a total sample size of 1,673 cases, including 778 cases of patients receiving SRL-based regimens and 895 cases in which patients received non-SRL-based regimens. Our data revealed that SRL containing prophylaxis can effectively reduce the incidence of grade II–IV acute GVHD (RR = 0.75, 95% CI: 0.68∼0.82, p < 0.0001). SRL-based prophylaxis was not associated with an improvement of grade III–IV acute GVHD (RR = 0.78, 95% CI: 0.59∼1.03, p = 0.08), chronic GVHD (p = 0.89), OS (p = 0.98), and relapse rate (p = 0.16). Despite its immunosuppressant effects, SRL-based regimens did not increase bacterial (p = 0.68), fungal (p = 0.70), or CMV (p = 0.10) infections. However, patients receiving SRL-based regimens had increased TMA (p < 0.00001) and VOD (p < 0.00001).

Conclusions

This meta-analysis indicates that addition of sirolimus is an effective alternative prophylaxis strategy for II–IV aGVHD but may cause endothelial cell injury and result in secondary TMA or VOD events.

A biomarker-guided, prospective, phase 2 trial of pre-emptive graft-versus-host disease therapy using anti-thymocyte globulin

BACKGROUND AIMS

Intensified immunosuppressive prophylaxis for graft-versus-host disease (GVHD) may be toxic and therefore warranted only in patients at high risk of developing GVHD. In patients who underwent allogeneic hematopoietic cell transplant at the authors' center, high serum soluble IL-2 receptor alpha (sIL-2Rα) and low IL-15 levels on day 7 post-transplant were found to predict a high risk of developing clinically significant GVHD (sGVHD), defined as grade 2-4 acute GVHD or moderate to severe chronic GVHD.

METHODS

This was a prospective, phase 2 trial in which high-risk patients (serum sIL-2Rα >4500 ng/L or IL-15 <31 ng/L) received rabbit anti-thymocyte globulin (ATG) 3 mg/kg on day 8 post-transplant. Controls consisted of patients who had their sIL-2Rα/IL-15 levels measured but did not participate in the trial. A total of 68 trial patients and 143 controls were accrued to this study. The primary endpoint was incidence of sGVHD.

RESULTS

There was a reduction in sGVHD in high-risk trial patients (received day 8 ATG) compared with high-risk controls (did not receive day 8 ATG) (sub-hazard ratio [SHR] = 0.48, P < 0.05). There was no significant difference between the groups in overall survival or relapse; however, there was a greater incidence of non-GVHD-associated non-relapse mortality in high-risk trial patients (SHR = 3.73, P < 0.05), mostly related to infections. This may be due in part to the biomarkers ineffectively stratifying GVHD risk.

CONCLUSIONS

Pre-emptive ATG therapy is both feasible and effective at reducing sGVHD without increasing relapse. Further mitigation strategies are needed to reduce the risk of infection associated with intensified GVHD prophylaxis. This study was registered at ClinicalTrials.gov (NCT01994824).

Hematopoietic Cell Transplantation, Version 2.2020, NCCN Clinical Practice Guidelines in Oncology

Hematopoietic cell transplantation (HCT) involves the infusion of hematopoietic progenitor cells into patients with hematologic disorders with the goal of re-establishing normal hematopoietic and immune function. HCT is classified as autologous or allogeneic based on the origin of hematopoietic cells. Autologous HCT uses the patient's own cells while allogeneic HCT uses hematopoietic cells from a human leukocyte antigen-compatible donor. Allogeneic HCT is a potentially curative treatment option for patients with certain types of hematologic malignancies, and autologous HCT is primarily used to support patients undergoing high-dose chemotherapy. Advances in HCT methods and supportive care in recent decades have led to improved survival after HCT; however, disease relapse and posttransplant complications still commonly occur in both autologous and allogeneic HCT recipients. Allogeneic HCT recipients may also develop acute and/or chronic graft-versus-host disease (GVHD), which results in immune-mediated cellular injury of several organs. The NCCN Guidelines for Hematopoietic Cell Transplantation focus on recommendations for pretransplant recipient evaluation and the management of GVHD in adult patients with malignant disease.

Allogeneic hematopoietic cell transplantation with non-myeloablative conditioning for patients with hematologic malignancies: Improved outcomes over two decades

We have used a non-myeloablative conditioning regimen for allogeneic hematopoietic cell transplantation for the past twenty years. During that period, changes in clinical practice have been aimed at reducing morbidity and mortality from infections, organ toxicity, and graft-versus-host disease. We hypothesized that improvements in clinical practice led to better transplantation outcomes over time. From 1997-2017, 1,720 patients with hematologic malignancies received low-dose total body irradiation +/- fludarabine or clofarabine before transplantation from HLA-matched sibling or unrelated donors, followed by mycophenolate mofetil and a calcineurin inhibitor ± sirolimus. We compared outcomes in three cohorts by year of transplantation: 1997 +/- 2003 (n=562), 2004 +/- 2009 (n=594), and 2010 +/- 2017 (n=564). The proportion of patients ≥60 years old increased from 27% in 1997 +/- 2003 to 56% in 2010-2017, and with scores from the Hematopoietic Cell Transplantation Comborbidity Index of ≥3 increased from 25% in 1997 +/- 2003 to 45% in 2010 +/- 2017. Use of unrelated donors increased from 34% in 1997 +/- 2003 to 65% in 2010-2017. When outcomes from 2004 +/- 2009 and 2010-2017 were compared to 1997 +/- 2003, improvements were noted in overall survival (P=.0001 for 2004-2009 and P <.0001 for 2010-2017), profression-free survival (P=.002 for 2004-2009 and P <.0001 for 2010 +/- 2017), non-relapse mortality (P<.0001 for 2004 +/- 2009 and P <.0001 for 2010 +/- 2017), and in rates of grades 2 +/- 4 acute and chronic graft-vs.-host disease. For patients with hematologic malignancies who underwent transplantation with non-myeloablative conditioning, outcomes have improved during the past two decades. Trials reported are registered under ClinicalTrials.gov identifiers: NCT00003145, NCT00003196, NCT00003954, NCT00005799, NCT00005801, NCT00005803, NCT00006251, NCT00014235, NCT00027820, NCT00031655, NCT00036738, NCT00045435, NCT00052546, NCT00060424, NCT00075478, NCT00078858, NCT00089011, NCT00104858, NCT00105001, NCT00110058, NCT00397813, NCT00793572, NCT01231412, NCT01252667, NCT01527045.

A prospective single-center study on CNI-free GVHD prophylaxis with everolimus plus mycophenolate mofetil in allogeneic HCT

We report a single-center phase I/II trial exploring the combination of everolimus (EVE) and mycophenolate mofetil (MMF) as calcineurin inhibitor (CNI)-free GVHD prophylaxis for 24 patients with hematologic malignancies and indication for allogeneic HCT after a high dose or reduced-intensity ablative conditioning. The study was registered as EudraCT-2007-001892-12 and Clinicaltrials.gov as NCT00856505. All patients received PBSC grafts and no graft failure occurred. 7/24 patients (29%) developed acute grades III and IV GVHD (aGVHD), 16/19 evaluable patients (84%) developed chronic GVHD (cGVHD) of all grades, and 6/19 (31.6%) of higher grades. No severe toxicities related to study medication were observed. The median follow-up of all surviving patients is 2177 days. The 3-year OS was 45.2% (95% CI: 27.4–61.4%), and the 3-year PFS was 38.7% (95% CI: 22.0–55.1%). The cumulative incidence of relapse at 1 year and 3 year was 25% (95% CI: 12.5–50.0%), and 33.3% (95% CI: 18.9–58.7%), the cumulative incidence of NRM at 1 year and 3 years was 20.8% (95%CI: 9.6–45.5%), and 29.2% (95%CI: 15.6–54.4%), respectively. The utilization of CNI-free GVHD prophylaxis with EVE+MMF resulted in high rates of acute and chronic GVHD. Therefore, we do not recommend a CNI-free combination of mTOR inhibitor EVE with MMF as the sole GVHD prophylaxis. In subsequent studies, this combination should be modified, e.g., with further components like post-transplant cyclophosphamide (PTCy) or anti-thymocyte globulin (ATG).

Dipeptidyl Peptidase 4 Inhibition for Prophylaxis of Acute Graft-versus-Host Disease

BACKGROUND

Dipeptidyl peptidase 4 (DPP-4; also known as CD26), a transmembrane receptor expressed on T cells, has a costimulatory function in activating T cells. In a mouse model, down-regulation of CD26 prevented graft-versus-host disease (GVHD) but preserved graft-versus-tumor effects. Whether inhibition of DPP-4 with sitagliptin may prevent acute GVHD after allogeneic stem-cell transplantation is not known.

METHODS

We conducted a two-stage, phase 2 clinical trial to test whether sitagliptin plus tacrolimus and sirolimus would reduce the incidence of grade II to IV acute GVHD from 30% to no more than 15% by day 100. Patients received myeloablative conditioning followed by mobilized peripheral-blood stem-cell transplants. Sitagliptin was given orally at a dose of 600 mg every 12 hours starting the day before transplantation until day 14 after transplantation.

RESULTS

A total of 36 patients who could be evaluated, with a median age of 46 years (range, 20 to 59), received transplants from matched related or unrelated donors. Acute GVHD occurred in 2 of 36 patients by day 100; the incidence of grade II to IV GVHD was 5% (95% confidence interval [CI], 1 to 16), and the incidence of grade III or IV GVHD was 3% (95% CI, 0 to 12). Nonrelapse mortality was zero at 1 year. The 1-year cumulative incidences of relapse and chronic GVHD were 26% (95% CI, 13 to 41) and 37% (95% CI, 22 to 53), respectively. GVHD-free, relapse-free survival was 46% (95% CI, 29 to 62) at 1 year. Toxic effects were similar to those seen in patients undergoing allogeneic stem-cell transplantation.

CONCLUSIONS

In this nonrandomized trial, sitagliptin in combination with tacrolimus and sirolimus resulted in a low incidence of grade II to IV acute GVHD by day 100 after myeloablative allogeneic hematopoietic stem-cell transplantation. (Funded by the National Heart, Lung, and Blood Institute; ClinicalTrials.gov number, NCT02683525.).

History of hematopoietic cell transplantation: challenges and progress

After more than 60 years of research in allogeneic hematopoietic cell transplantation (HCT), this therapy has advanced from one that was declared dead in the 1960s to a standard treatment of otherwise fatal malignant and non-malignant blood diseases. To date, close to 1.5 million hematopoietic cell transplants have been performed in more than 1,500 transplantation centers worldwide. This review will highlight the enormous efforts by numerous investigators throughout the world who have brought the experimental field of HCT to clinical reality, examine ongoing challenges, and provide insights for the future.

Feasibility of thiotepa addition to the fludarabine-busulfan conditioning with tacrolimus/sirolimus as graft vs host disease prophylaxis

In classical reduced-intensity conditioning (RIC) regimens, including the fludarabine and busulphan (BF) combination, sirolimus and tacrolimus (SIR-TAC) as graft vs host disease (GVHD) prophylaxis has shown acceptable results. The outcomes of SIR-TAC in a more intense RIC regimen as Thiotepa-fludarabine-busulfan (TBF) have been hardly investigated. This retrospective study included all consecutive patients receiving an allogeneic hematopoietic stem cell transplantation for myeloid malignancies (January 2009-2017) conditioned with either TBF or BF and receiving SIR-TAC. Patients receiving TBF presented higher non-relapse mortality (31.6 vs 12.3%, p = .01), along with shorter overall survival (51.8% vs 77.8%, p < .01) at 2 years than patients treated with BF. There were no significant differences in the cumulative incidence of grade II-IV acute GVHD or moderate-severe chronic GVHD or relapse between both groups. These results suggest that TBF does not seem to improve the traditional RIC BF regimen, at least when associated with SIR-TAC prophylaxis.

Moving Past Ganciclovir and Foscarnet: Advances in CMV Therapy

PURPOSE OF REVIEW

CMV DNA polymerase inhibitors such as ganciclovir and foscarnet have dramatically reduced the burden of CMV infection in the HCT recipient. However, their use is often limited by toxicities and resistance. Agents with novel mechanisms and favorable toxicity profiles are critically needed. We review recent developments in CMV antivirals and immune-based approaches to mitigating CMV infection.

RECENT FINDINGS

Letermovir, an inhibitor of the CMV terminase complex, was approved in 2017 for primary CMV prophylaxis in adult seropositive allogeneic HCT recipients. Maribavir, an inhibitor of the CMV UL97 kinase, is currently in two phase 3 treatment studies. Adoptive immunotherapy using third-party T cells has proven safe and effective in preliminary studies. Vaccine development continues, with several promising candidates currently under study. No longer limited to DNA polymerase inhibitors, the prevention and treatment of CMV infections in the HCT recipient is a rapidly evolving field which should translate into improvements in CMV-related outcomes.

HLA-Haploidentical Hematopoietic Cell Transplantation for Treatment of Nonmalignant Diseases Using Nonmyeloablative Conditioning and Post-Transplant Cyclophosphamide

Allogeneic hematopoietic cell transplant (HCT) is often the only curative therapy for patients with nonmalignant diseases; however, many patients do not have an HLA-matched donor. Historically, poor survival has been seen after HLA-haploidentical HCT because of poor immune reconstitution, increased infections, graft-versus-host disease (GVHD), and graft failure. Encouraging results have been reported using a nonmyeloablative T cell-replete HLA-haploidentical transplant approach in patients with hematologic malignancies. Here we report the outcomes of 23 patients with various nonmalignant diseases using a similar approach. Patients received HLA-haploidentical bone marrow (n = 17) or granulocyte colony-stimulating factor-mobilized peripheral blood stem cell (n = 6) grafts after conditioning with cyclophosphamide 50 mg/kg, fludarabine 150 mg/m², and 2 or 4 Gy total body irradiation. Postgrafting immunosuppression consisted of cyclophosphamide, mycophenolate mofetil, tacrolimus, ± sirolimus. Median patient age at HCT was 10.8 years. Day 100 transplant-related mortality (TRM) was 0%. Two patients died at later time points, 1 from intracranial hemorrhage/disseminated fungal infection in the setting of graft failure and 1 from infection/GVHD. The estimated probabilities of grades II to IV and III to IV acute GVHD at day 100 and 2-year National Institutes of Health consensus chronic GVHD were 78%, 26%, and 42%, respectively. With a median follow-up of 2.5 years, the 2-year overall and event-free rates of survival were 91% and 78%, respectively. These results are encouraging and demonstrate favorable disease-specific lineage engraftment with low TRM in patients with nonmalignant diseases using nonmyeloablative conditioning followed by T cell-replete HLA-haploidentical grafts. However, additional strategies are needed for GVHD prevention to make this a viable treatment approach for patients with nonmalignant diseases.

Allogeneic Hematopoietic Cell Transplantation in the Outpatient Setting

Conditioning with fludarabine and low-dose total-body irradiation before allogeneic hematopoietic cell transplantation (HCT) enabled treating older or medically infirm patients with advanced hematologic malignancies in the outpatient setting. Between December 1997 and June 2017, 1037 patients with hematologic malignancies received peripheral blood stem cell (PBSC) grafts from HLA-matched or 1 HLA antigen/allele-mismatched related or unrelated donors. Median age was 58 (range, 18 to 80) years. Serious comorbidities with Hematopoietic Cell Transplantation-Specific Comorbidity Index (HCT-CI) scores ≥3 were present in 52% of patients. We found that 47% of patients were either never hospitalized or only had an overnight hospital stay for infusion of late-arriving PBSCs while 53% were admitted for a median of 6 days. Main reasons for admission were infection, fever, graft-versus-host disease, and regimen-related toxicity. Two thirds of admissions occurred within 3 weeks of HCT. The 5-year risk of nonrelapse mortality (NRM) was 26% among hospitalized patients and 13% among nonhospitalized patients. Significant risk factors for hospitalization included unrelated transplants, 1 HLA antigen-mismatched transplant, high HCT-CI scores, and diagnosis of nonmyeloma malignancies. Significant risk factors for NRM were hospitalization, older age, unrelated transplants, and high HCT-CI scores. Ambulatory allogeneic HCT is feasible and safe.

Addition of sirolimus to standard cyclosporine plus mycophenolate mofetil-based graft-versus-host disease prophylaxis for patients after unrelated non-myeloablative haemopoietic stem cell transplantation: a multicentre, randomised, phase 3 trial

BACKGROUND

Acute graft-versus-host-disease (GVHD) after non-myeloablative human leucocyte antigen (HLA)-matched, unrelated donor, allogeneic haemopoietic stem cell transplantation (HSCT) is associated with considerable morbidity and mortality. This trial aimed to evaluate the efficacy of adding sirolimus to the standard cyclosporine and mycophenolate mofetil prophylaxis therapy for preventing acute GVHD in this setting.

METHODS

This multicentre, randomised, phase 3 trial took place at nine HSCT centres based in the USA, Denmark, and Germany. Eligible patients were diagnosed with advanced haematological malignancies treatable by allogeneic HSCT, had a Karnofsky score greater than or equal to 60, were aged older than 50 years, or if they were aged 50 years or younger, were considered at high risk of regimen-related toxicity associated with a high-dose pre-transplantation conditioning regimen. Patients were randomly allocated by an adaptive randomisation scheme stratified by transplantation centre to receive either the standard GVHD prophylaxis regimen (cyclosporine and mycophenolate mofetil) or the triple-drug combination regimen (cyclosporine, mycophenolate mofetil, and sirolimus). Patients and physicians were not masked to treatment. All patients were prepared for HSCT with fludarabine (30 mg/m² per day) 4, 3, and 2 days before receiving 2 or 3 Gy total body irradiation on the day of HSCT (day 0). In both study groups, 5·0 mg/kg of cyclosporine was administered orally twice daily starting 3 days before HSCT, and (in the absence of GVHD) tapered from day 96 through to day 150. In the standard GVHD prophylaxis group, 15 mg/kg of mycophenolate mofetil was given orally three times daily from day 0 until day 30, then twice daily until day 150, and (in the absence of GVHD) tapered off by day 180. In the triple-drug group, mycophenolate mofetil doses were the same as in the standard group, but the drug was discontinued on day 40. Sirolimus was started 3 days before HSCT, taken orally at 2 mg once daily and adjusted to maintain trough concentrations between 3-12 ng/mL through to day 150, and (in the absence of GVHD) tapered off by day 180. The primary endpoint was the cumulative incidence of grade 2-4 acute GVHD at day 100 post-transplantation. Secondary endpoints were non-relapse mortality, overall survival, progression-free survival, cumulative incidence of grade 3-4 acute GVHD, and cumulative incidence of chronic GVHD. Efficacy and safety analyses were per protocol, including all patients who received conditioning treatment and underwent transplantation. Toxic effects were measured according to the Common Terminology Criteria for Adverse Events (CTCAE). The current study was closed prematurely by recommendation of the Data and Safety Monitoring Board on July 27, 2016, after 168 patients received the allocated intervention, based on the results of a prespecified interim analysis for futility. This study is registered with ClinicalTrials.gov, number NCT01231412.

FINDINGS

Participants were recruited between Nov 1, 2010, and July 27, 2016. Of 180 patients enrolled in the study, 167 received the complete study intervention and were included in safety and efficacy analyses: 77 patients in the standard GVHD prophylaxis group and 90 in the triple-drug group. At the time of analysis, median follow-up was 48 months (IQR 31-60). The cumulative incidence of grade 2-4 acute GVHD at day 100 was lower in the triple-drug group compared with the standard GVHD prophylaxis group (26% [95% CI 17-35] in the triple-drug group vs 52% [41-63] in the standard group; HR 0·45 [95% CI 0·28-0·73]; p=0·0013). After 1 and 4 years, non-relapse mortality increased to 4% (95% CI 0-9) and 16% (8-24) in the triple-drug group and 16% (8-24) and 32% (21-43) in the standard group (HR 0·48 [0·26-0·90]; p=0·021). Overall survival at 1 year was 86% (95% CI 78-93) in the triple-drug group and 70% in the standard group (60-80) and at 4 years it was 64% in the triple-drug group (54-75) and 46% in the standard group (34-57%; HR 0·62 [0·40-0·97]; p=0·035). Progression-free survival at 1 year was 77% (95% CI 68-85) in the triple-drug group and 64% (53-74) in the standard drug group, and at 4 years it was 59% in the triple-drug group (49-70) and 41% in the standard group (30-53%; HR 0·64 [0·42-0·99]; p=0·045). We observed no difference in the cumulative incidence of grade 3-4 acute GVHD (2% [0-5] in the triple-drug group vs 8% [2-14] in the standard group; HR 0·55 [0·16-1·96]; p=0·36) and chronic GVHD (49% [39-59] in triple-drug group vs 50% [39-61] in the standard group; HR 0·94 [0·62-1·40]; p=0·74). In both groups the most common CTCAE grade 4 or higher toxic effects were pulmonary.

INTERPRETATION

Adding sirolimus to cyclosporine and mycophenolate mofetil resulted in a significantly lower proportion of patients developing acute GVHD compared with patients treated with cyclosporine and mycophenolate mofetil alone. Based on these results, the combination of cyclosporine, mycophenolate mofetil, and sirolimus has become the new standard GVHD prophylaxis regimen for patients treated with non-myeloablative conditioning and HLA-matched unrelated HSCT at the Fred Hutchinson Cancer Research Center.

FUNDING

National Institutes of Health.

Mechanism of action of posttransplantation cyclophosphamide: more than meets the eye

For high-risk and refractory hematological malignancies, allogeneic hematopoietic stem cell transplantation (alloHSCT) is the only available curative therapy, with benefits derived from the antigenic disparity between recipient cancer and the incoming immune system. This immunologic mismatch can also lead to lethal graft-versus-host disease (GVHD), and immunosuppression strategies, including high-dose posttransplantation cyclophosphamide (PTCy), have been developed to allow for safe alloHSCT delivery. In this issue of JCI, Wachsmuth et al. present the results of preclinical studies designed to evaluate the mechanisms that underlie efficacy of PTCy after alloHSCT. The results of this study challenge previous reports indicating that alloreactive T cell elimination and thymic clonal deletion are primary mediators of PTCy efficacy and provide strong evidence to support FoxP3+CD4+ Tregs as important effectors of PTCy benefits.

Total body irradiation dose escalation decreases risk of progression and graft rejection after hematopoietic cell transplantation for myelodysplastic syndromes or myeloproliferative neoplasms

A non-myeloablative regimen of fludarabine and 200 cGy total body irradiation combined with post-grafting immunosuppression with mycophenolate mofetil and a calcineurin inhibitor facilitates allogeneic hematopoietic cell transplantation from HLA-matched related or unrelated donors in older patients and/or those with comorbidities. However, outcomes of prior studies have been disappointing in patients with myelodysplastic syndromes or myeloproliferative neoplasms due to high incidences of progression or graft failure (together termed hematopoietic cell transplantation-failure). We hypothesized that escalating the total body irradiation dose may improve the outcomes and subsequently performed a phase II total body irradiation dose-escalation trial. Patients with median age 66 years were enrolled in two arms to receive non-myeloablative conditioning followed by hematopoietic cell transplantation with total body irradiation dose escalation for excessive hematopoietic cell transplantation-failure: Arm A: myeloproliferative neoplasm/myelodysplastic syndrome low risk (n=36); and Arm B: myelodysplastic syndrome high-risk/chronic myelomonocytic leukemia (n=41). Total body irradiation dose levels were: Level-1 (300 cGy), Level-2 (400 cGy), or Level-3 (450 cGy). Patients received intravenous fludarabine 30 mg/m² for three days. Total body irradiation was administered on day 0 followed by infusion of peripheral blood stem cells from HLA-matched related (n=30) or unrelated (n=47) donors. Post-grafting immunosuppression with mycophenolate mofetil and cyclosporine was administered. The primary end point was day 200 hematopoietic cell transplant failure, with the objective of reducing the incidence to <20%. The primary end point was reached on Arm A at dose Level-1 (300 cGy total body irradiation) with a cumulative incidence of day 200 hematopoietic cell transplant failure of 11%, and on Arm B at dose Level-3 (450 cGy) with a cumulative incidence of day 200 hematopoietic cell transplant failure of 9%. Increasing the total body irradiation dose leads to a higher success rate with non-myeloablative conditioning by reducing relapse and rejection. Further studies are necessary to decrease non-relapse mortality, especially among patients with high-risk disease. Trial registered under clinicaltrials.gov identifier: NCT00397813.

Low-Dose Anti-T Lymphoglobulin as Prophylaxis for Graft-versus-Host Disease in Unrelated Donor Transplantations for Acute Leukemias and Myelodysplastic Syndromes

Chronic graft-versus-host disease (cGVHD) is a major complication after stem cell transplantation (HSCT). Several randomized studies already demonstrated that anti-T lymphoglobulin (ATLG) is effective in preventing GVHD after myeloablative unrelated and HLA-identical sibling transplants. However, the issue of doses and the potential increase of relapses still remain unsolved. Here we report data on 190 patients with acute leukemia and myelodysplastic syndrome who underwent an unrelated HSCT with low-dose ATLG (15 to 30 mg/kg) given at an earlier timing (days -6 to -2). HSCT was performed from HLA 10/10 (n = 62, 33%), 9/10 (n = 91, 48%), 8/10 (n = 30, 16%), and <8/10 (n = 7, 4%) identical unrelated donor. Peripheral blood was the stem cell source in 42% (n = 80). Median follow-up was 51 months. Grades II to IV and III to IV acute GVHD were 26% and 9%, respectively, and 2-year overall and moderate to severe cGVHD were 23% and 14%, respectively. The 3-year incidences of relapse and nonrelapse mortality were 26% and 18%, respectively. The rates of 3-year overall survival (OS), disease-free survival (DFS), and GVHD-free and relapse-free survival (GRFS) were 60%, 56% and 44%, respectively. Factors such as younger donor, good performance status, and early disease were associated with better outcome in terms of OS, DFS, and GRFS. Our data indicate that doses of ATLG lower that those used in randomized clinical trials can be used for GVHD prevention, even in the adult setting, without clear increases in relapse and infections; these findings need to be further validated by a prospective randomized study.

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.

Nonmyeloablative allogeneic hematopoietic cell transplantation

Most hematological malignancies occur in older patients. Until recently these patients and those with comorbidities were not candidates for treatment with allogeneic hematopoietic transplantation because they were unable to tolerate the heretofore used high-dose conditioning regimens. The finding that many of the cures achieved with allogeneic hematopoietic transplantation were due to graft-versus-tumor effects led to the development of less toxic and well-tolerated reduced intensity and nonmyeloablative regimens. These regimens enabled allogeneic engraftment, thereby setting the stage for graft-versus-tumor effects. This review summarizes the encouraging early results seen with the new regimens and discusses the two hurdles that need to be overcome for achieving even greater success, disease relapse and graft-versus-host disease.

Risk Factors for Graft-Versus-Host Disease After Transplantation of Hematopoietic Stem Cells from Unrelated Donors in the China Marrow Donor Program

BACKGROUND We identified risk factors for acute and chronic graft-versus-host disease (aGVHD and cGVHD, respectively) in recipients after hematopoietic stem cell transplantation (HSCT) from unrelated donors in the China Marrow Donor Program (CMDP). MATERIAL AND METHODS We analyzed follow-up clinical information from 1824 patients who underwent HSCT between 2001 and 2010. RESULTS The incidence of aGVHD and cGVHD after transplantation was 49.29% and 27.3%, respectively. aGVHD incidence decreased as HLA matching increased (p<0.001). Incidence of aGVHD and cGVHD was higher in 2 HLA-A locus donor/recipient groups (02: 01/02: 06 and 02: 01/02: 07; p≤0.022). aGVHD incidence was associated with patient age, absence of rabbit anti-thymocyte globulin (ATG) pretreatment, and disease status (p≤0.040). aGVHD appeared to be a risk factor for cGVHD, and total body irradiation (TBI) was also associated with cGVHD. Patients with cGVHD after transplantation had a higher survival rate than patients without cGVHD (p<0.001), which may be due to reduced relapse rates. Survival was also associated with ATG prophylaxis and disease status. CONCLUSIONS The incidence of GVHD after HSCT from unrelated donors in the Chinese population is similar to the results reported from other countries. A high degree of HLA matching, a conditioning regimen without TBI, and the use of ATG may reduce the incidence of aGVHD.

Pharmacokinetics, Pharmacodynamics, and Pharmacogenomics of Immunosuppressants in Allogeneic Hematopoietic Cell Transplantation: Part II

Part I of this article included a pertinent review of allogeneic hematopoietic cell transplantation (alloHCT), the role of postgraft immunosuppression in alloHCT, and the pharmacokinetics, pharmacodynamics, and pharmacogenomics of the calcineurin inhibitors and methotrexate. In this article (Part II), we review the pharmacokinetics, pharmacodynamics, and pharmacogenomics of mycophenolic acid (MPA), sirolimus, and the antithymocyte globulins (ATG). We then discuss target concentration intervention (TCI) of these postgraft immunosuppressants in alloHCT patients, with a focus on current evidence for TCI and on how TCI may improve clinical management in these patients. Currently, TCI using trough concentrations is conducted for sirolimus in alloHCT patients. Several studies demonstrate that MPA plasma exposure is associated with clinical outcomes, with an increasing number of alloHCT patients needing TCI of MPA. Compared with MPA, there are fewer pharmacokinetic/dynamic studies of rabbit ATG and horse ATG in alloHCT patients. Future pharmacokinetic/dynamic research of postgraft immunosuppressants should include '-omics'-based tools: pharmacogenomics may be used to gain an improved understanding of the covariates influencing pharmacokinetics as well as proteomics and metabolomics as novel methods to elucidate pharmacodynamic responses.

Pharmacokinetics, Pharmacodynamics and Pharmacogenomics of Immunosuppressants in Allogeneic Haematopoietic Cell Transplantation: Part I

Although immunosuppressive treatments and target concentration intervention (TCI) have significantly contributed to the success of allogeneic haematopoietic cell transplantation (alloHCT), there is currently no consensus on the best immunosuppressive strategies. Compared with solid organ transplantation, alloHCT is unique because of the potential for bidirectional reactions (i.e. host-versus-graft and graft-versus-host). Postgraft immunosuppression typically includes a calcineurin inhibitor (cyclosporine or tacrolimus) and a short course of methotrexate after high-dose myeloablative conditioning, or a calcineurin inhibitor and mycophenolate mofetil after reduced-intensity conditioning. There are evolving roles for the antithymyocyte globulins (ATGs) and sirolimus as postgraft immunosuppression. A review of the pharmacokinetics and TCI of the main postgraft immunosuppressants is presented in this two-part review. All immunosuppressants are characterized by large intra- and interindividual pharmacokinetic variability and by narrow therapeutic indices. It is essential to understand immunosuppressants' pharmacokinetic properties and how to use them for individualized treatment incorporating TCI to improve outcomes. TCI, which is mandatory for the calcineurin inhibitors and sirolimus, has become an integral part of postgraft immunosuppression. TCI is usually based on trough concentration monitoring, but other approaches include measurement of the area under the concentration-time curve (AUC) over the dosing interval or limited sampling schedules with maximum a posteriori Bayesian personalization approaches. Interpretation of pharmacodynamic results is hindered by the prevalence of studies enrolling only a small number of patients, variability in the allogeneic graft source and variability in postgraft immunosuppression. Given the curative potential of alloHCT, the pharmacodynamics of these immunosuppressants deserves to be explored in depth. Development of sophisticated systems pharmacology models and improved TCI tools are needed to accurately evaluate patients' exposure to drugs in general and to immunosuppressants in particular. Sequential studies, first without and then with TCI, should be conducted to validate the clinical benefit of TCI in homogenous populations; randomized trials are not feasible, because there are higher-priority research questions in alloHCT. In Part I of this article, we review the alloHCT process to facilitate optimal design of pharmacokinetic and pharmacodynamics studies. We also review the pharmacokinetics and TCI of calcineurin inhibitors and methotrexate.

New perspectives on the use of mTOR inhibitors in allogeneic haematopoietic stem cell transplantation and graft-versus-host disease

Inhibition of the mechanistic target of rapamycin (mTOR) has been exploited largely both in solid tumour oncology and solid organ transplantation. More recently mTOR inhibitors such as sirolimus and everolimus have been introduced to the field of allogeneic haematopoietic stem cell transplantation where their unique combination of immunosuppressive purposes offering reduced nephrotoxicity and potential antimalignant effects reflect a unique drug profile that has led to their widespread use in both prophylaxis and therapy of graft-versus-host disease (GVHD). On the other hand haematological insufficiency, infectious complications as well as vasculopathies, have been frequently reported as limiting toxicities. Here, we review both the retrospective and prospective experience available to date and stress the need for prospective registration trials to reduce off label use and improve patient safety by optimizing dosing and enhancing pharmacovigilance. Furthermore, we speculate on the future role of mTOR inhibitors in allogeneic haematopoietic stem cell transplantation.

The addition of sirolimus to the graft-versus-host disease prophylaxis regimen in reduced intensity allogeneic stem cell transplantation for lymphoma: a multicentre randomized trial

Inhibition of the mechanistic target of rapamycin (mTOR) pathway has clinical activity in lymphoma. The mTOR inhibitor sirolimus has been used in the prevention and treatment of graft-versus-host disease (GVHD) after allogeneic haematopoietic stem cell transplantation (HSCT). A retrospective study suggested that patients with lymphoma undergoing reduced intensity conditioning (RIC) HSCT who received sirolimus as part of their GVHD prophylaxis regimen had a lower rate of relapse. We therefore performed a multicentre randomized trial comparing tacrolimus, sirolimus and methotrexate to standard regimens in adult patients undergoing RIC HSCT for lymphoma in order to assess the possible benefit of sirolimus on HSCT outcome. 139 patients were randomized. There was no difference overall in 2-year overall survival, progression-free survival, relapse, non-relapse mortality or chronic GVHD. However, the sirolimus-containing arm had a significantly lower incidence of grade II-IV acute GVHD (9% vs. 25%, P = 0·015), which was more marked for unrelated donor grafts. In conclusion, the addition of sirolimus for GVHD prophylaxis in RIC HSCT is associated with no increased overall toxicity and a lower risk of acute GVHD, although it does not improve survival; this regimen is an acceptable option for GVHD prevention in RIC HSCT. This trial is registered at clinicaltrials.gov (NCT00928018).

Association of fludarabine pharmacokinetic/dynamic biomarkers with donor chimerism in nonmyeloablative HCT recipients

PURPOSE

Fludarabine monophosphate (fludarabine) is an integral component of many reduced-intensity conditioning regimens for hematopoietic cell transplantation (HCT). Fludarabine's metabolite, 9-β-D-arabinofuranosyl-2-fluoroadenine (F-ara-A), undergoes cellular uptake and activation to form the active cytotoxic metabolite fludarabine triphosphate (F-ara-ATP), which inhibits cellular DNA synthesis in CD4(+) and CD8(+) cells. In this study, we evaluated whether fludarabine-based pharmacologic biomarkers were associated with clinical outcomes in HCT recipients.

METHODS

Participants with hematologic diseases were conditioned with fludarabine and low-dose total body irradiation (TBI) followed by allogeneic HCT and post-grafting immunosuppression. After fludarabine administration, we evaluated pharmacological biomarkers for fludarabine-F-ara-A area under the curve (AUC) and the ratio of circulating CD4(+) and CD8(+) cells (CD4(+)/CD8(+) ratio) after fludarabine administration-in 102 patients; F-ara-ATP accumulation rate in enriched CD4(+) and CD8(+) cells was evaluated in 36 and 34 patients, respectively.

RESULTS

Interpatient variability in the pharmacological biomarkers was high, ranging from 3.7-fold (F-ara-A AUC) to 39-fold (F-ara-ATP in CD8(+) cells). Circulating CD8(+) cells were more sensitive to fludarabine administration. A population pharmacokinetic-based sampling schedule successfully allowed for estimation of F-ara-A AUC in this outpatient population. There was a poor correlation between the F-ara-AUC and the F-ara-ATP accumulation rate in CD4(+) (R (2) = 0.01) and CD8(+) cells (R (2) = 0.00). No associations were seen between the four biomarkers and clinical outcomes (day +28 donor T cell chimerism, acute graft-versus-host disease (GVHD), neutrophil nadirs, cytomegalovirus reactivation, chronic GVHD, relapse, non-relapse mortality, or overall mortality).

CONCLUSIONS

Considerable interpatient variability exists in pharmacokinetic and fludarabine-based biomarkers, but these biomarkers are not associated with clinical outcomes in fludarabine/TBI-conditioned patients.

The efficacy and safety of sirolimus-based graft-versus-host disease prophylaxis in patients undergoing allogeneic hematopoietic stem cell transplantation: a meta-analysis of randomized controlled trials

BACKGROUND

The efficacy and safety of sirolimus (SIR)-based graft-versus-host disease (GVHD) prophylaxis in patients who were subjected to allogeneic hematopoietic stem cell transplantation (allo-HSCT) remain to be clarified; this meta-analysis was conducted to evaluate these factors.

STUDY DESIGN AND METHODS

Data from original research were obtained from PubMed, Embase, and Cochrane central register of controlled trials databases. Randomized controlled trials (RCTs) evaluating the efficacy of SIR-based prophylaxis in allo-HSCT were included. The risk ratio (RR), with a 95% confidence interval (CI), was used to pool data. The random effects model was used, irrespective of the presence or absence of heterogeneity.

RESULTS

Five RCTs were included in the meta-analysis. SIR was observed to significantly decrease the incidence of Grade II to IV acute GVHD (aGVHD; RR, 0.65; 95% CI, 0.47-0.89). However, the incidence of Grade III to IV aGVHD and chronic GVHD was not decreased (RR, 0.91; 95% CI, 0.59-1.40; RR, 1.04; 95% CI, 0.88-1.23, respectively). An analysis of the toxic effects of SIR revealed that SIR effected a significant increase in the incidence of sinusoidal obstructive syndrome (RR, 2.24; 95% CI, 1.26-4.01), while that of thrombotic microangiopathy was not significantly increased (RR, 2.48; 95% CI, 0.87-7.06). Moreover, SIR did not improve event-free survival and overall survival (RR, 0.97; 95% CI, 0.85-1.10; and RR, 0.92; 95% CI, 0.82-1.02, respectively).

CONCLUSION

This meta-analysis indicated that the SIR-based regimen is an effective and safe alternative prophylaxis strategy for GVHD.

Prolonged sirolimus administration after allogeneic hematopoietic cell transplantation is associated with decreased risk for moderate-severe chronic graft-versus-host disease

Effective pharmacological strategies employed in allogeneic hematopoietic cell transplantation should prevent serious chronic graft-versus-host disease and facilitate donor-recipient immune tolerance. Based on demonstrated pro-tolerogenic activity, sirolimus (rapamycin) is an agent with promise to achieve these goals. In a long-term follow-up analysis of a randomized phase II trial comparing sirolimus/tacrolimus versus methotrexate/tacrolimus for graft-versus-host disease prevention in matched sibling or unrelated donor transplant, we examined the impact of prolonged sirolimus administration (≥ 1 year post-transplant). Median follow-up time for surviving patients at time of this analysis was 41 months (range 27-60) for sirolimus/tacrolimus and 49 months (range 29-63) for methotrexate/tacrolimus. Sirolimus/tacrolimus patients had significantly lower National Institutes of Health Consensus moderate-severe chronic graft-versus-host disease (34% vs. 65%; P=0.004) and late acute graft-versus-host disease (20% vs. 43%; P=0.04). While sirolimus/tacrolimus patients had lower prednisone exposure and earlier discontinuation of tacrolimus (median time to tacrolimus discontinuation 368 days vs. 821 days; P=0.002), there was no significant difference in complete immune suppression discontinuation (60-month estimate: 43% vs. 31%; P=0.78). Prolonged sirolimus administration represents a viable approach to mitigate risk for moderate-severe chronic and late acute graft-versus-host disease. Further study of determinants of successful immune suppression discontinuation is needed.

Immune Recovery after Allogeneic Hematopoietic Stem Cell Transplantation Following Flu-TBI versus TLI-ATG Conditioning

PURPOSE

A conditioning regimen for allogeneic hematopoietic cell transplantation (HCT) combining total lymphoid irradiation (TLI) plus anti-thymocyte globulin (ATG) has been developed to induce graft-versus-tumor effects without graft-versus-host disease (GVHD).

EXPERIMENTAL DESIGN

We compared immune recovery in 53 patients included in a phase II randomized study comparing nonmyeloablative HCT following either fludarabine plus 2 Gy total body irradiation (TBI arm, n = 28) or 8 Gy TLI plus ATG (TLI arm, n = 25).

RESULTS

In comparison with TBI patients, TLI patients had a similarly low 6-month incidence of grade II-IV acute GVHD, a lower incidence of moderate/severe chronic GVHD (P = 0.02), a higher incidence of CMV reactivation (P < 0.001), and a higher incidence of relapse (P = 0.01). While recovery of total CD8(+) T cells was similar in the two groups, with median CD8(+) T-cell counts reaching the normal values 40 to 60 days after allo-HCT, TLI patients had lower percentages of naïve CD8 T cells. Median CD4(+) T-cell counts did not reach the lower limit of normal values the first year after allo-HCT in the two groups. Furthermore, CD4(+) T-cell counts were significantly lower in TLI than in TBI patients the first 6 months after transplantation. Interestingly, while median absolute regulatory T-cell (Treg) counts were comparable in TBI and TLI patients, Treg/naïve CD4(+) T-cell ratios were significantly higher in TLI than in TBI patients the 2 first years after transplantation.

CONCLUSIONS

Immune recovery differs substantially between these two conditioning regimens, possibly explaining the different clinical outcomes observed (NCT00603954).

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) .