Effect of up-front daclizumab when combined with steroids for the treatment of acute graft-versus-host disease: results of a randomized trial

Ruxolitinib plus steroids for acute graft versus host disease: a multicenter, randomized, phase 3 trial

Newly diagnosed patients with high-risk acute graft-versus-host disease (aGVHD) often experience poor clinical outcomes and low complete remission rates. Ruxolitinib with corticosteroids showed promising efficacy in improving response and failure free survival in our phase I study. This study (ClinicalTrials.gov: NCT04061876) sought to evaluate the safety and effectiveness of combining ruxolitinib (RUX, 5 mg/day) with corticosteroids (1 mg/kg/day methylprednisolone, RUX/steroids combined group) versus using methylprednisolone alone (2 mg/kg/day, steroids-only group). Newly diagnosed patients with intermediate- or high-risk aGVHD were included, with risk levels classified by either the Minnesota aGVHD Risk Score or biomarker assessment. Patients were randomized in a ratio of 1:1 into 2 groups: 99 patients received RUX combined with methylprednisolone, while the other 99 received methylprednisolone alone as the initial treatment. The RUX/steroids group showed a significantly higher overall response rate (ORR) on day 28 (92.9%) compared to the steroids-only group (70.7%, Odds Ratio [OR] = 5.8; 95% Confidence Interval [CI], 2.4-14.0; P < 0.001). Similarly, the ORR on day 56 was higher in the RUX/steroids group (85.9% vs. 46.5%; OR = 7.07; 95% CI, 3.36-15.75; P < 0.001). Additionally, the 18-month failure-free survival was significantly better in the RUX/steroids group (57.2%) compared to the steroids-only group (33.3%; Hazard Ratio = 0.46; 95% CI, 0.31-0.68; P < 0.001). Adverse events (AEs) frequencies were comparable between both groups, with the exception of fewer grade 4 AEs in the RUX/steroids group (26.3% vs. 50.5% P = 0.005). To our knowledge, this study is the first prospective, randomized controlled trial to demonstrate that adding ruxolitinib to the standard methylprednisolone regimen provides an effective and safe first-line treatment for newly diagnosed high-risk acute GVHD.

Mini-dose methotrexate combined with methylprednisolone for the initial treatment of acute GVHD: a multicentre, randomized trial

BACKGROUND

There is an urgent unmet need for effective initial treatment for acute graft-versus-host disease (aGVHD) adding to the standard first-line therapy with corticosteroids after allogeneic haematopoietic stem cell transplantation (allo-HSCT).

METHODS

We performed a multicentre, open-label, randomized, phase 3 study. Eligible patients (aged 15 years or older, had received allo-HSCT for a haematological malignancy, developed aGVHD, and received no previous therapies for aGVHD) were randomly assigned (1:1) to receive either 5 mg/m2 MTX on Days 1, 3, or 8 and then combined with corticosteroids or corticosteroids alone weekly.

RESULTS

The primary endpoint was the overall response rate (ORR) on Day 10. A total of 157 patients were randomly assigned to receive either MTX plus corticosteroids (n = 78; MTX group) or corticosteroids alone (n = 79; control group). The Day 10 ORR was 97% for the MTX group and 81% for the control group (p = .005). Among patients with mild aGVHD, the Day 10 ORR was 100% for the MTX group and 86% for the control group (p = .001). The 1-year estimated failure-free survival was 69% for the MTX group and 41% for the control group (p = .002). There were no differences in treatment-related adverse events between the two groups.

CONCLUSIONS

In conclusion, mini-dose MTX combined with corticosteroids can significantly improve the ORR in patients with aGVHD and is well tolerated, although it did not achieve the prespecified 20% improvement with the addition of MTX.

TRIAL REGISTRATION

The trial was registered with clinicaltrials.gov (NCT04960644).

Basiliximab Treatment for Patients With Steroid-Refractory Acute Graft-Versus-Host Disease Following Matched Sibling Donor Hematopoietic Stem Cell Transplantation

Basiliximab is an important treatment for steroid-refractory acute graft-versus-host disease (SR-aGVHD). We performed this retrospective study to evaluate the efficacy and safety of basiliximab treatment in SR-aGVHD patients following matched sibling donor hematopoietic stem cell transplantation (MSD-HSCT) (n = 63). Overall response rate (ORR) was 63.5% and 54% at any time and at day 28 after basiliximab treatment. Grade III-IV aGVHD before basiliximab treatment predicted a poor ORR after basiliximab treatment. The rates of virus, bacteria, and fungi infections were 54%, 23.8%, and 3.1%, respectively. With a median follow-up of 730 (range, 67-3,042) days, the 1-year probability of overall survival and disease-free survival after basiliximab treatment were 58.6% (95% confidence interval [CI] = 47.6%-72.2%) and 55.4% (95% CI = 44.3%-69.2%), respectively. The 3-year cumulative incidence of relapse and non-relapse mortality after basiliximab treatment were 18.9% (95% CI = 8.3%-29.5%) and 33.8% (95% CI = 21.8%-45.7%), respectively. Comorbidities burden before allo-HSCT, severity of aGVHD and liver aGVHD before basiliximab treatment showed negative influences on survival. Thus, basiliximab was safe and effective treatment for SR-aGVHD following MSD-HSCT.

Novel developments in the prophylaxis and treatment of acute GVHD

Acute graft-versus-host disease (aGVHD) is a major life-threatening complication after allogeneic hematopoietic cell transplant. Traditional standard prophylaxis for aGVHD has included a calcineurin inhibitor plus an antimetabolite, whereas treatment has relied mainly on corticosteroids, followed by multiple nonstandard second-line options. In the past decade, this basic framework has been reshaped by approval of antithymocyte globulin products, the emergence of posttransplant cyclophosphamide, and recent pivotal trials studying abatacept and vedolizumab for GVHD prophylaxis, whereas ruxolitinib was approved for corticosteroid-refractory aGVHD treatment. Because of this progress, routine acute GVHD prophylaxis and treatment practices are starting to shift, and results of ongoing trials are eagerly awaited. Here, we review recent developments in aGVHD prevention and therapy, along with ongoing and future planned clinical trials in this space, outlining what future goals should be and the limitations of current clinical trial designs and end points.

Multi-parametric MRI in the diagnosis and scoring of gastrointestinal acute graft-versus-host disease

OBJECTIVES

Acute gastrointestinal graft-versus-host disease (GI-aGVHD) is a severe complication of allogeneic hematopoietic stem cell transplantation (HSCT). Diagnosis relies on clinical, endoscopic, and pathological investigations. Our purpose is to assess the value of magnetic resonance imaging (MRI) in the diagnosis, staging, and prediction of GI-aGVHD-related mortality.

METHODS

Twenty-one hematological patients who underwent MRI for clinical suspicion of acute GI-GVHD were retrospectively selected. Three independent radiologists, blinded to the clinical findings, reanalyzed MRI images. The GI tract was evaluated from stomach to rectum by analyzing fifteen MRI signs suggestive of intestinal and peritoneal inflammation. All selected patients underwent colonoscopy with biopsies. Disease severity was determined on the basis of clinical criteria, identifying 4 stages of increasing severity. Disease-related mortality was also assessed.

RESULTS

The diagnosis of GI-aGVHD was histologically confirmed with biopsy in 13 patients (61.9%). Using 6 major signs (diagnostic score), MRI showed 84.6% sensitivity and 100% specificity in identifying GI-aGVHD (AUC = 0.962; 95% confidence interval 0.891-1). The proximal, middle, and distal ileum were the segments most frequently affected by the disease (84.6%). Using all 15 signs of inflammation (severity score), MRI showed 100% sensitivity and 90% specificity for 1-month related mortality. No correlation with the clinical score was found.

CONCLUSION

MRI has proved to be an effective tool for diagnosing and scoring GI-aGVHD, with a high prognostic value. If larger studies will confirm these results, MRI could partly replace endoscopy, thus becoming the primary diagnostic tool for GI-aGVHD, being more complete, less invasive, and more easily repeatable.

KEY POINTS

• We have developed a new promising MRI diagnostic score for GI-aGVHD with a sensitivity of 84.6% and specificity of 100%; results are to be confirmed by larger multicentric studies. • This MRI diagnostic score is based on the six MRI signs most frequently associated with GI-aGVHD: small-bowel inflammatory involvement, bowel wall stratification on T2-w images, wall stratification on post-contrast T1-w images, ascites, and edema of retroperitoneal fat and declivous soft tissues. • A broader MRI severity score based on 15 MRI signs showed no correlation with clinical staging but high prognostic value (100% sensitivity, 90% specificity for 1-month related mortality); these results also need to be confirmed by larger studies.

Mini-dose methotrexate combined with methylprednisolone as a first-line treatment for acute graft-versus-host disease: A phase 2 trial

Background and Objectives

Acute graft-versus-host disease (aGvHD) remains a major complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methylprednisolone (MP; 1-2 mg/kg/day) remains the standard first-line therapy for aGvHD, although no response is detected in nearly one-half of the patients with aGvHD. This study aimed to investigate the feasibility of mini-dose methotrexate (MTX) combined with standard-dose MP as a front-line therapy for aGvHD.

Materials and Methods

A prospective Phase 2 clinical trial was performed to evaluate the safety and efficacy of 5 mg/m2 MTX combined with 1 mg/kg/day MP as the initial therapy in 31 patients with aGvHD. Moreover, the effects of MTX combined with MP were explored in a humanized xenogeneic murine model of aGvHD.

Results

The overall response and complete response rate at 7 days after the initial treatment were 100% and 83%, respectively. The overall response rate on day 28 was 87%. The complete response rates for aGvHD grades I, II, and III were 100% (6/6), 82% (18/22), and 66% (2/3), respectively. Grade 3 toxicities occurred in only three patients presenting with cytopenia. Importantly, MTX and MP demonstrated synergistic effects on ameliorating aGvHD in humanized xenogeneic murine model.

Conclusion

The current study suggests that mini-dose MTX combined with standard-dose MP could potentially become a novel first-line therapy for patients with aGvHD.

A prospective phase 2 clinical trial of a C5a complement inhibitor for acute GVHD with lower GI tract involvement

Involvement of lower gastrointestinal tract (LGI) occurs in 60% of patients with graft-versus-host-disease (GVHD). Complement components C3 and C5 are involved in GVHD pathogenesis. In this phase 2a study, we evaluated the safety and efficacy of ALXN1007, a monoclonal antibody against C5a, in patients with newly diagnosed LGI acute GVHD receiving concomitant corticosteroid. Twenty-five patients were enrolled; one was excluded from the efficacy analysis based upon negative biopsy. Most patients (16/25, 64%) had acute leukemia; 52% (13/25) had an HLA-matched unrelated donor; and 68% (17/25) received myeloablative conditioning. Half the patients (12/24) had a high biomarker profile, Ann Arbor score 3; 42% (10/24) had high-risk GVHD per Minnesota classification. Day-28 overall response was 58% (13/24 complete response, 1/24 partial response), and 63% by Day-56 (all complete responses). Day-28 overall response was 50% (5/10) in Minnesota high-risk and 42% (5/12) in high-risk Ann Arbor patients, increasing to 58% (7/12) by Day-56. Non-relapse mortality at 6-months was 24% (95% CI 11-53). The most common treatment-related adverse event was infection (6/25, 24%). Neither baseline complement levels (except for C5), activity, nor inhibition of C5a with ALXN1007 correlated with GVHD severity or responses. Further studies are needed to evaluate the role of complement inhibition in GVHD treatment.

Glucocorticoid and glycolysis inhibitors cooperatively abrogate acute graft-versus-host disease

Although glucorticosteroids (GCs) are the standard first-line therapy for acute graft-versus-host disease (aGvHD), nearly 50% of aGvHD patients have no response to GCs. The role of T cell metabolism in murine aGvHD was recently reported. However, whether GCs and metabolism regulators could cooperatively suppress T cell alloreactivity and ameliorate aGvHD remains to be elucidated. Increased glycolysis, characterized by elevated 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3), and higher rates of glucose consumption and lactate production were found in T cells from aGvHD patients. Genetic upregulation of PFKFB3 induced T cell proliferation and differentiation into proinflammatory cells. In a humanized mouse model, PFKFB3-overexpressing or PFKFB3-silenced T cells aggravated or prevented aGvHD, respectively. Importantly, our integrated data from patient samples in vitro, in a humanized xenogeneic murine model of aGvHD and graft-versus-leukaemia (GVL) demonstrate that GCs combined with a glycolysis inhibitor could cooperatively reduce the alloreactivity of T cells and ameliorate aGvHD without loss of GVL effects. Together, the current study indicated that glycolysis is critical for T cell activation and induction of human aGvHD. Therefore, the regulation of glycolysis offers a potential pathogenesis-oriented therapeutic strategy for aGvHD patients. GCs combined with glycolysis inhibitors promises to be a novel first-line combination therapy for aGvHD patients.

First-line steroid-free systemic treatment of acute and chronic graft-versus-host disease after novel prophylaxis regimens

In the early randomized trials the efficacy of calcineurin inhibitors (CNI) in the treatment of graft-versus-host disease (GVHD) was comparable to corticosteroids (CS), but these results became obsolete with the introduction of CNIs in prophylaxis. Recently several effective CNI-free GVHD prophylaxis regimens were introduced based on posttransplantation cyclophosphamide (PTCY) and αβ ex vivo T-cell depletion (αβ-TCD). Among patients treated under these protocols 34 patients with grade II-IV acute (aGVHD) and 40 with moderate and severe chronic (cGVHD) disease were treated with CNIs or other CS-free regimens as the first line. Overall response rate (ORR) was significantly higher in cGVHD than in aGVHD: 80% (95% CI 68-92) vs 47% (95% CI 30-64%), p = 0.0031. In aGVHD it was almost completely restricted to isolated stage III skin GVHD. In cGVHD patients with moderate disease ORR was higher than in severe: 96% (95% CI 88-100%) vs 56% (95%CI 32-81%), p = 0.0022. Two-year overall survival was 76% (95% CI 58-87%) in aGVHD and 95% (95% CI 81-99%) in cGVHD. Failure-free survival was 21% (95% CI 9-37%) in aGVHD and 81% (95% CI 64-91%) in cGVHD. Patients responding to steroid-free regimens had lower use of systemic antibiotics (p = 0.0095), antifungals (p = 0.0319) and antivirals (p < 0.0001).

A biomarker signature to predict complete response to itacitinib and corticosteroids in acute graft-versus-host disease

A broad proteomic analysis was conducted to identify and evaluate candidate biomarkers potentially predictive of response to treatment with an oral selective Janus kinase 1 (JAK1) inhibitor, itacitinib, in acute graft‐versus‐host disease (GVHD). Plasma samples from 25 participants (identification cohort; NCT02614612) were used to identify novel biomarkers that were tested in a validation cohort from a placebo‐controlled, randomised trial (n = 210; NCT03139604). The identification cohort received corticosteroids plus 200 or 300 mg itacitinib once daily. The validation cohort received corticosteroids plus 200 mg itacitinib once daily or placebo. A broad proteomic analysis was conducted using a proximity extension assay. Baseline and longitudinal comparisons were performed with unpaired t‐test and one‐way analysis of variance used to evaluate biomarker level changes. Seven candidate biomarkers were identified. Monocyte‐chemotactic protein (MCP)3, pro‐calcitonin/calcitonin (ProCALCA/CALCA), together with a previously identified prognostic acute GVHD biomarker, regenerating islet‐derived protein (REG)3A, stratified complete responders from non‐responders (participants with progressive disease) to itacitinib, but not placebo, potentially representing predictive biomarkers of itacitinib in acute GVHD. ProCALCA/CALCA, suppressor of tumorigenicity (ST)2, and tumour necrosis factor receptor (TNFR)1 were significantly reduced over time by itacitinib in responders, potentially representing response‐to‐treatment biomarkers. Novel biomarkers have the potential to identify patients with acute GVHD that may respond to itacitinib plus corticosteroid treatment (NCT02614612; NCT03139604).

Harnessing Treg Homeostasis to Optimize Posttransplant Immunity: Current Concepts and Future Perspectives

CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Tregs) are functionally distinct subsets of mature T cells with broad suppressive activity and have been shown to play an important role in the establishment of immune tolerance after allogeneic hematopoietic stem cell transplantation (HSCT). Tregs exhibit an activated phenotype from the stage of emigration from the thymus and maintain continuous proliferation in the periphery. The distinctive feature in homeostasis enables Tregs to respond sensitively to small environmental changes and exert necessary and sufficient immune suppression; however, on the other hand, it also predisposes Tregs to be susceptible to apoptosis in the inflammatory condition post-transplant. Our studies have attempted to define the intrinsic and extrinsic factors affecting Treg homeostasis from the acute to chronic phases after allogeneic HSCT. We have found that altered cytokine environment in the prolonged post-HSCT lymphopenia or peri-transplant use of immune checkpoint inhibitors could hamper Treg reconstitution, leading to refractory graft-versus-host disease. Using murine models and clinical trials, we have also demonstrated that proper intervention with low-dose interleukin-2 or post-transplant cyclophosphamide could restore Treg homeostasis and further amplify the suppressive function after HSCT. The purpose of this review is to reconsider the distinctive characteristics of post-transplant Treg homeostasis and discuss how to harness Treg homeostasis to optimize posttransplant immunity for developing a safe and efficient therapeutic strategy.

The Pathophysiology and Treatment of Graft-Versus-Host Disease: Lessons Learnt From Animal Models

Allogeneic hematopoietic cell transplantation (HCT) is a curative treatment for hematologic malignancies, bone marrow failure syndromes, and inherited immunodeficiencies and metabolic diseases. Graft-versus-host disease (GVHD) is the major life-threatening complication after allogeneic HCT. New insights into the pathophysiology of GVHD garnered from our understanding of the immunological pathways within animal models have been pivotal in driving new therapeutic paradigms in the clinic. Successful clinical translations include histocompatibility matching, GVHD prophylaxis using cyclosporine and methotrexate, posttransplant cyclophosphamide, and the use of broad kinase inhibitors that inhibit cytokine signaling (e.g. ruxolitinib). New approaches focus on naïve T cell depletion, targeted cytokine modulation and the inhibition of co-stimulation. This review highlights the use of animal transplantation models to guide new therapeutic principles.

A phase 1 trial of itacitinib, a selective JAK1 inhibitor, in patients with acute graft-versus-host disease

Acute graft-versus-host disease (aGVHD) following allogeneic hematopoietic cell transplantation (HCT) is a primary cause of nonrelapse mortality and a major barrier to successful transplant outcomes. Itacitinib is a Janus kinase (JAK)1-selective inhibitor that has demonstrated efficacy in preclinical models of aGVHD. We report results from the first registered study of a JAK inhibitor in patients with aGVHD. This was an open-label phase 1 study enrolling patients aged ≥18 years with first HCT from any source who developed grade IIB to IVD aGVHD. Patients with steroid-naive or steroid-refractory aGVHD were randomized 1:1 to itacitinib 200 mg or 300 mg once daily plus corticosteroids. The primary endpoint was safety and tolerability; day 28 overall response rate (ORR) was the main secondary endpoint. Twenty-nine patients (200 mg, n = 14; 300 mg, n = 15) received ≥1 dose of itacitinib and were included in safety and efficacy assessments. One dose-limiting toxicity was reported (grade 3 thrombocytopenia attributed to GVHD progression in a patient receiving 300 mg itacitinib with preexisting thrombocytopenia). The most common nonhematologic treatment-emergent adverse event was diarrhea (48.3%, n = 14); anemia occurred in 11 patients (38%). ORR on day 28 for all patients in the 200-mg and 300-mg groups was 78.6% and 66.7%, respectively. Day 28 ORR was 75.0% for patients with treatment-naive aGVHD and 70.6% in those with steroid-refractory aGVHD. All patients receiving itacitinib decreased corticosteroid use over time. In summary, itacitinib was well tolerated and demonstrated encouraging efficacy in patients with steroid-naive or steroid-refractory aGVHD, warranting continued clinical investigations. This trial was registered at www.clinicaltrials.gov as #NCT02614612.

Randomized phase II trial of extracorporeal phototherapy and steroids vs. steroids alone for newly diagnosed acute GVHD

Steroids remain the initial therapy for acute graft-vs.-host disease (AGVHD). Strategies to improve response and minimize steroid exposure are needed. We report results of a randomized, adaptive, Bayesian-designed, phase II trial of prednisone with or without extracorporeal photopheresis (ECP) as an initial therapy for patients with newly diagnosed AGVHD. The primary endpoint was success at day 56 defined as: alive, in remission, achieving AGVHD response without additional therapy, and on <1 mg/kg at day 28 and <0.5 mg/kg on day 56 of steroids. Eighty-one patients were randomized to the ECP arm (n = 51) or steroids alone (n = 30). Median age was 54 years (range: 17-75); 90% had grade II AGVHD and 10% had grades III and IV AGVHD, with skin (85%), upper (22%)/lower (22%) gastrointestinal, and liver (10%) involvement. The ECP arm had a higher probability of success (0.815) and exceeded the predefined threshold for determining the investigational arm promising. ECP was potentially more beneficial than steroids-alone in skin-only AGVHD (response rate: 72% vs. 57%, respectively) than for visceral-organ AGVHD (47% vs. 43%, respectively). The addition of ECP to steroids may result in higher GVHD response as initial therapy for AGVHD, especially for patients with skin-only involvement.

Steroid-refractory acute graft-versus-host disease graded III-IV in pediatric patients. A mono-institutional experience with a long-term follow-up

aGvHD remains a major obstacle to successful HSCT. We report our experience on steroid-refractory aGvHD III and IV from 1989 to 2017. Ninety patients with aGvHD III or IV were stratified according to the HSCT year: 1989-1998, 1999-2007, and 2008-2017 and to aGvHD extension (GvHD III vs IV) and finally the probability of OS, RI, and TRM was calculated accordingly. aGvHD III patients had a substantial improvement over time: day 100 OS raised from 64% (95% CI 39-89) in the first cohort to 100% in the latest (P = .022), and it was mainly due to a reduction of TRM (it was 28% [95% CI 12-65] in the first cohort to 0% in the latest (P = .01). The aGvHD IV patients did not present a significant improvement. Day 100 OS was 42% (95% CI 16-68) in the first group and 54% (95% CI 25-83) in the year 2008-2017 (P = NS), and the day-100 TRM was very similar (it was 57% [95% CI 36-90] in the first cohort and 45% [95% CI 23-89] in the latest (P = NS). We report significant improvements in OS and TRM in patients diagnosed with grade III aGvHD. Patients with the most severe aGvHD appear to have no or fewer benefits on long-term outcomes.

How to Make an Immune System and a Foreign Host Quickly Cohabit in Peace? The Challenge of Acute Graft-Versus-Host Disease Prevention After Allogeneic Hematopoietic Cell Transplantation

Allogeneic hematopoietic cell transplantation (alloHCT) has been used as cellular immunotherapy against hematological cancers for more than six decades. Its therapeutic efficacy relies on the cytoreductive effects of the conditioning regimen but also on potent graft-versus-tumor (GVT) reactions mediated by donor-derived immune cells. However, beneficial GVT effects may be counterbalanced by acute GVHD (aGVHD), a systemic syndrome in which donor immune cells attack healthy tissues of the recipient, resulting in severe inflammatory lesions mainly of the skin, gut, and liver. Despite standard prophylaxis regimens, aGVHD still occurs in approximately 20–50% of alloHCT recipients and remains a leading cause of transplant-related mortality. Over the past two decades, advances in the understanding its pathophysiology have helped to redefine aGVHD reactions and clinical presentations as well as developing novel strategies to optimize its prevention. In this review, we provide a brief overview of current knowledge on aGVHD immunopathology and discuss current approaches and novel strategies being developed and evaluated in clinical trials for aGVHD prevention. Optimal prophylaxis of aGVHD would prevent the development of clinically significant aGVHD, while preserving sufficient immune responsiveness to maintain beneficial GVT effects and immune defenses against pathogens.

Ruxolitinib Combined with Corticosteroids as First-Line Therapy for Acute Graft-versus-Host Disease in Haploidentical Peripheral Blood Stem Cell Transplantation Recipients

Corticosteroids are commonly used as first-line treatment for acute graft-versus-host disease (aGVHD); however, they are effective in only approximately one-half of patients. This study prospectively evaluated the use of ruxolitinib combined with 1 mg/kg methylprednisolone in the initial treatment of aGVHD. A total of 32 patients were enrolled. aGVHD involved the skin (53.1%), gastrointestinal tract (68.8%), and liver (6.0%). The complete response rate at day +28 was 96.9%. The 1-year and 2-year cumulative incidence rates of chronic GVHD were 9.4% and 13.8%, respectively. The 1- year cumulative incidence of nonrelapse mortality was 8.7%, and the Kaplan-Meier curve estimated 1-year overall survival after transplantation at 73.4%. This prospective study suggests that patients with aGVHD show a high response rate to ruxolitinib (5 mg/day) combined with 1 mg/kg/day methylprednisolone. This novel regimen was seen to spare steroid exposure, alleviate toxicity, and improve long-term survival.

Extracorporeal photopheresis as first-line strategy in the treatment of acute graft-versus-host disease after hematopoietic stem cell transplantation: A single-center experience

BACKGROUND AIMS

Corticosteroids are the standard first-line treatment for acute graft-versus-host disease (aGVHD), but they are associated with many complications, and less than half of patients have a sustained response.

METHODS

To improve outcomes, we performed a retrospective study to analyze the efficacy of the addition of extracorporeal photopheresis (ECP) to low-dose corticosteroids in 37 adult patients (median age, 57 years) with skin-predominant aGVHD (grade I, n = 17; grade II, n = 18; and grade III, n = 2). All patients received ECP in combination with 1 mg/kg prednisone (n = 26) or topical steroids (n = 11).

RESULTS

Overall response rate was 81% after a median of three ECP procedures (range, 2-8), including 22 complete responses (CR, 59%) and eight very good partial responses (VGPR, 22%). The 11 patients treated with topical corticosteroids achieved CR. Furthermore, 16 (62%) patients reached prednisone withdrawal at a median of 100 days (range, 42-174 days) after its initiation. Eighteen patients developed chronic GVHD (cGVHD); 11 of them (who were in CR of aGVHD) had a new-onset cGVHD, and seven experienced progressive cGVHD (five non-responding and two VGPR patients). A second-line immunosuppressive treatment was initiated in only five (14%) non-responding patients. With a median follow-up of 31 months (range, 6-57 months) 2-year overall survival and non-relapse mortality were 74% and 11%, respectively.

CONCLUSIONS

Overall, the combination of low-dose corticosteroids and ECP appear to be safe and effective for first-line treatment of skin predominant aGVHD.

Targeting Signal 3 Extracellularly and Intracellularly in Graft-Versus-Host Disease

Allogeneic hematopoietic stem cell transplantation (allo-HCT) holds curative potential for many hematological disorders. However, the pathophysiology of the desired graft-versus-tumor effect is linked to life-threatening complications of acute graft-versus-host disease (GVHD). Allogeneic donor T lymphocytes are essential for causing GVHD, and their activation relies on the coordination of TCR engagement and co-stimulation, also known as Signal 1 and Signal 2. In addition to these signals, a network of secreted cytokines by immune cells provides a third signal, Signal 3, that is critical for the initiation and maintenance of GVHD. Strategies to target Signal 3 in human diseases have shown therapeutic benefit for inflammatory disorders such as Rheumatoid Arthritis and Inflammatory Bowel Disease. However, despite our growing understanding of their role in GVHD, the success of targeting individual cytokines has been modest with some notable exceptions. This review aims to describe current approaches toward targeting Signal 3 in clinical GVHD, and to highlight emerging studies in immune cell biology that may be harnessed for better clinical translation.

Therapeutic options for steroid-refractory acute and chronic GVHD: an evolving landscape

Introduction: The traditional therapeutic modalities to manage SR-acute GVHD have focused on the inhibition of the alloreactive T-cell response, while in the setting of SR-chronic GVHD the focus has been on a combination of T-cell and B-cell targeting strategies. However, new therapeutic modalities have shown promise. The purpose of this review is to summarize the current treatment landscape of SR-acute and chronic GVHD.Areas covered: A systematic search of MEDLINE, EMBASE, and clinicaltrials.gov databases for published articles, abstracts, and clinical trials pertaining to available therapeutic modalities for SR-acute and SR-chronic GVHD was conducted. Also highlighted is a number of ongoing clinical trials in both SR-acute and SR-chronic GVHD with strategies targeting the JAK-1/2 pathway, the Treg:Tcon ratio, the immunomodulation mediated by mesenchymal stem cells, and the gut microbiome, among others. Expert opinion: Ruxolitinib has emerged as the preferred therapeutic modality for SR-acute GVHD, with alpha-1-antitrypsin and extracorporeal photophoresis (ECP) being reasonable alternatives. Ruxolitinib and Ibrutinib are among the preferred options for SR-chronic GVHD, with ECP being a viable alternative particularly if the skin is involved. A number of novel therapeutic modalities, including those enhancing the activity of regulatory T-cells have shown great promise in early phase trials of SR-chronic GVHD.

Glucocorticoids delivered by inorganic-organic hybrid nanoparticles mitigate acute graft-versus-host disease and sustain graft-versus-leukemia activity

Glucocorticoids (GCs) are widely used to treat acute graft-versus-host disease (aGvHD) due to their immunosuppressive activity, but they also reduce the beneficial graft-versus-leukemia (GvL) effect of the allogeneic T cells contained in the graft. Here, we tested whether aGvHD therapy could be improved by delivering GCs with the help of inorganic-organic hybrid nanoparticles (IOH-NPs) that preferentially target myeloid cells. IOH-NPs containing the GC betamethasone (BMP-NPs) efficiently reduced morbidity, mortality, and tissue damage in a totally MHC mismatched mouse model of aGvHD. Therapeutic activity was lost in mice lacking the GC receptor (GR) in myeloid cells, confirming the cell type specificity of our approach. BMP-NPs had no relevant systemic activity but suppressed cytokine and chemokine gene expression locally in the small intestine, which presumably explains their mode of action. Most importantly, BMP-NPs delayed the development of an adoptively transferred B cell lymphoma better than the free drug, although the overall incidence was unaffected. Our findings thus suggest that employing IOH-NPs could diminish the risk of relapse associated with GC therapy of aGvHD patients while still allowing to efficiently ameliorate the disease.

Treatment of steroid resistant acute graft versus host disease with an anti-CD26 monoclonal antibody-Begelomab

We have treated 69 patients with steroid refractory acute graft versus host disease (SR-aGvHD), with an anti-CD26 monoclonal antibody (Begelomab): 28 patients in two prospective studies (EudraCT No. 2007-005809-21; EudraCT No. 2012-001353-19), and 41 patients on a compassionate use study. The median age of patients was 42 and 44 years; the severity of GvHD was as follows: grade II in 8 patients, grade III in 33, and grade IV in 28 patients. There were no adverse events directly attributable to the antibody. Day 28 response was 75% in the prospective studies and 61% in the compassionate use patients, with complete response rates of 11 and 12%. Response for grade III GvHD was 83 and 73% in the two groups; response in grade IV GvHD was 66 and 56% in the two groups. Non relapse mortality (NRM) at 6 months was 28 and 38%. Overall there were 64, 56, 68% responses for skin, liver, and gut stage 3-4 GvHD. The overall survival at 1 year was 50% for the prospective studies and 33% for the compassionate use patients. In conclusion, Begelomab induces over 60% responses in SR-aGvHD, including patients with severe gut and liver GvHD, having failed one or more lines of treatment.

Regional intra-arterial steroid treatment in 120 patients with steroid-resistant or -dependent GvHD

GvHD results in death in the majority of steroid-resistant patients. This report assesses the safety and efficacy of two regional intra-arterial steroid (IAS) treatment protocols in the largest published cohort of patients with resistant/dependent hepatic and/or gastrointestinal GvHD, as well as identification of predictors of response to IAS and survival. One hundred and twenty patients with hepatic, gastrointestinal GvHD or both were given IAS. Gastrointestinal initial response (IR) and complete response (CR) were documented in 67.9% and 47.6%, respectively, whereas hepatic IR/CR in 54.9% and 33.3%, respectively. The predictors of gastrointestinal CR were lower peak GvHD and steroid-dependent (SD) GvHD. The predictors for hepatic CR were male patient, reduced intensity conditioning and SD GvHD. Twenty-six of the 120 patients (21.6%) are currently alive (median follow-up for the survivors 91.5 months). The 12 months' overall survival is 30% with no treatment-associated deaths. Predictors of 12 months' survival were as follows: first transplant, age<20 years, non-TBI regimen and GvHD CR. Shorter time to gastrointestinal IR but not time to hepatic IR was associated with improved 12 months' survival. IAS appears to be safe and effective. Gastrointestinal treatment is more effective than hepatic treatment. In our study, we conclude our current recommendations for IAS treatment.

The Potential of Mesenchymal Stromal Cells as Treatment for Severe Steroid-Refractory Acute Graft-Versus-Host Disease: A Critical Review of the Literature

BACKGROUND

Acute graft-versus-host disease (GvHD) is a major complication after allogeneic hematopoietic stem cell transplantation which causes high morbidity and mortality among patients who do not respond to steroid treatment. Mesenchymal stromal cells (MSCs) have immune modulatory abilities and earned their place in the treatment of GvHD after a pediatric patient remarkably recovered from steroid-refractory acute GvHD with MSC salvage therapy. Large, prospective clinical trials evaluating the potency of MSCs have however not been published.

METHODS

To evaluate the therapeutic potential of MSCs in the treatment of steroid-refractory acute GvHD, we conducted a systematic literature search. We included all studies that focused on MSC treatment of adult allogeneic hematopoietic stem cell transplantation recipients with grades III to IV steroid-refractory acute GvHD and were transparent about their methods and patient selection criteria.

RESULTS

From a total of 255 articles, 9 articles met the quality criteria for this study. The proportion of patients achieving complete resolution of all symptoms (complete response, CR) varied between 8% and 83%. Four of the 9 studies reported CR rates above 50%. The GvHD grade at the time of treatment was identified as a predictor of clinical response. Interestingly, complete response but not partial response to MSCs was associated with overall survival. No serious side effects of MSC therapy were reported.

CONCLUSIONS

MSC treatment does improve the outcome in steroid-refractory acute GvHD patients but well-designed, prospective randomized clinical trials are needed to confirm the potential of MSCs as salvage therapy for steroid-refractory GvHD and to identify those patients that will benefit most.

Tissue tolerance: a distinct concept to control acute GVHD severity

Target tissue damage occurs as a consequence of pathological immune responses following allogeneic stem cell transplantation resulting in acute graft-versus-host disease (GVHD). Among those who study infections in plants, it is well recognized that tissues play a distinct role from the immune system in mediating disease severity. Recently, this has also been appreciated in mammals. However, the severity of immunopathology in the context of alloimmune diseases such as acute GVHD has been mainly understood and managed by direct targeting of immune cells to generate immune tolerance. The role of tissue-intrinsic factors that might contribute to regulation of acute GVHD severity has been largely overlooked. Here, we introduce the concept of "tissue tolerance" to discuss the tissue-specific programs that contribute to target tissue resilience, repair, and regeneration, and mitigate severity of acute GVHD without altering the load or function of alloreactive immune cells.

CD25 Blockade Delays Regulatory T Cell Reconstitution and Does Not Prevent Graft-versus-Host Disease After Allogeneic Hematopoietic Cell Transplantation

Daclizumab, a humanized monoclonal antibody, binds CD25 and blocks formation of the IL-2 receptor on T cells. A study of daclizumab as acute graft-versus-host disease (GVHD) prophylaxis after unrelated bone marrow transplantation was conducted before the importance of CD25⁺FOXP3⁺ regulatory T cells (Tregs) was recognized. Tregs can abrogate the onset of GVHD. The relation between Tregs and a graft-versus-malignancy effect is not fully understood. An international, multicenter, double-blind clinical trial randomized 210 adult or pediatric patients to receive 5 weekly doses of daclizumab at 0.3 mg/kg (n = 69) or 1.2 mg/kg (n = 76) or placebo (n = 65) after unrelated marrow transplantation for treatment of hematologic malignancies or severe aplastic anemia. The risk of acute GVHD did not differ among the groups (P = .68). Long-term follow-up of clinical outcomes and correlative analysis of peripheral blood T cell phenotype suggested that the patients treated with daclizumab had an increased risk of chronic GVHD (hazard ratio [HR], 1.49; 95% confidence interval [CI], 1.0 to 2.3; P = .08) and a decreased risk of relapse (HR, 0.57; 95% CI, 0.3 to 1.0; P = .05), but similar survival (HR, 0.89; 95% CI, 0.6 to 1.3; P = .53). T cells from a subset of patients (n = 107) were analyzed by flow cytometry. Compared with placebo, treatment with daclizumab decreased the proportion of Tregs among CD4 T cells at days 11-35 and increased the proportion of central memory cells among CD4 T cells at 1 year. Prophylactic administration of daclizumab does not prevent acute GVHD, but may increase the risk of chronic GVHD and decrease the risk of relapse. By delaying Treg reconstitution and promoting immunologic memory, anti-CD25 therapy may augment alloreactivity and antitumor immunity.

The long-term outcome of reduced-intensity allogeneic stem cell transplantation from a matched related or unrelated donor, or haploidentical family donor in patients with leukemia: a retrospective analysis of data from the China RIC Cooperative Group

This study compared 6-year follow-up data from patients undergoing reduced-intensity conditioning (RIC) transplantation with an HLA-matched related donor (MRD), an HLA-matched unrelated donor (MUD), or an HLA-haploidentical donor (HID) for leukemia. Four hundred and twenty-seven patients from the China RIC Cooperative Group were enrolled, including 301 in the MRD, 79 in the HID, and 47 in the MUD groups. The conditioning regimen involved fludarabine combined with anti-lymphocyte globulin and cyclophosphamide. Graft-versus-host disease (GVHD) prophylaxis was administered using cyclosporin A (CsA) and mycophenolate mofetil (MMF). Four hundred and nineteen patients achieved stable donor chimerism. The incidence of stage II-IV acute GVHD in the HID group was 44.3 %, significantly higher than that in the MRD (23.6 %) and MUD (19.1 %) groups. The 1-year transplantation-related mortality (TRM) rates were 44.3, 17.6, and 21.3, respectively. Event-free survival (EFS) at 6 years in the HID group was 36.7 %, significantly lower than that of the MRD and MUD groups (59.1 and 66.0 %, P < 0.001 and P = 0.001, respectively). For advanced leukemia, the relapse rate of the HID group was 18.5 %, lower than that of the MRD group (37.5 %, P = 0.05), but the EFS at 6 years was 31.7 and 30.4 % (P > 0.05), respectively. RIC transplantation with MRD and MUD had similar outcome in leukemia which is better than that with HID. RIC transplantation with HID had lower relapsed with higher TRM and GVHD rate, particularly in advanced leukemias. RIC transplantation with MRD and MUD had similar outcomes in leukemia and they were better than those with HID. RIC transplantation with HID had a lower relapse rate but higher TRM and GVHD rates, particularly in cases of advanced leukemia.

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.

Therapeutic targets and emerging treatment options in gastrointestinal acute graft-versus-host disease

Introduction

Graft-versus-host disease (GVHD) continues to be the major lethal complication of allogeneic hematopoietic stem cell transplantation (HCT) but the standard of care, high dose steroids, has not changed in 40 years. Approximately 50% of GVHD patients will develop steroid refractory disease, typically involving the gastrointestinal (GI) tract, which has a very poor prognosis. Newly developed GVHD biomarker-based risk scores provide the first opportunity to treat patients at the onset of symptoms according to risk of steroid failure. Furthermore, improvements in our understanding of the pathobiology of GVHD, its different signaling pathways, involved cytokines, and the role of post-translational and epigenetic modifications, has identified new therapeutic targets for clinical trials.

Areas covered

This manuscript summarizes the pathophysiology, diagnosis, staging, current and new targeted therapies for GVHD, with an emphasis on GI GVHD. A literature search on PubMed was undertaken and the most relevant references included.

Expert Opinion

The standard treatment for GVHD, high dose steroids, offers less than optimal outcomes as well as significant toxicities. Better treatments, especially for GI GVHD, are needed to reduce non-relapse mortality after allogeneic HCT. The identification of high risk patients through a biomarker-defined scoring system offers a personalized approach to a disease that still requires significant research attention.

Advances in understanding the pathogenesis of graft-versus-host disease

Allogeneic haematopoietic stem cell transplantation (HCT) is a potent immunotherapy with curative potential for several haematological disorders. Overcoming the immunological barrier of acute graft-versus-host disease (GVHD) remains a fundamental impediment to expanding the efficacy of HCT. GVHD reflects a complex pathological interaction between the innate and adaptive immune systems of the host and donor. Over the past decade there has been a tremendous advancement in our understanding of the cellular and molecular underpinnings of this devastating disease. In this review, we cover several recently appreciated facets of GVHD pathogenesis including novel extracellular mediators of inflammation, immune subsets, intracellular signal transduction, post-translation modifications and epigenetic regulation. We begin to develop general themes regarding the immunological pathways in GVHD pathogenesis, discuss critical outstanding questions, and explore new avenues for GVHD treatment and prevention.

Steroids Versus Steroids Plus Additional Agent in Frontline Treatment of Acute Graft-versus-Host Disease: A Systematic Review and Meta-Analysis of Randomized Trials

Despite extensive research in the last few decades, progress in treatment of acute graft-versus-host disease (aGVHD), a common complication of allogeneic hematopoietic cell transplantation (HCT), has been limited and steroids continue to be the standard frontline treatment. Randomized clinical trials (RCTs) have failed to find a beneficial effect of escalating immunosuppression using additional agents. Considering the small number of RCTs, limited sample sizes, and frequent early termination because of anticipated futility, we conducted a systematic review and an aggregate data meta-analysis to explore whether a true efficacy signal has been missed because of the limitations of individual RCTs. Seven reports met our inclusion criteria. The control arm in all studies was 2 mg/kg/day prednisone (or equivalent). The additional agent(s) used in the experimental arm(s) were higher-dose steroids, antithymocyte globulin, infliximab, anti-interleukin-2 receptor antibody (daclizumab and BT563), CD5-specific immunotoxin, and mycophenolate mofetil. Random effects meta-analysis revealed no efficacy signal in pooled response rates at various times points. Overall survival at 100 days was significantly worse in the experimental arm (relative risk [RR], .83; 95% confidence interval [CI], .74 to .94; P = .004, data from 3 studies) and showed a similar trend (albeit not statistically significantly) at 1 year as well (RR, .86; 95% CI, .68 to 1.09; P = .21, data from 5 studies). In conclusion, these results argue against the value of augmented generic immunosuppression beyond steroids for frontline treatment of aGVHD and emphasize the importance of developing alternative strategies. Novel forms of immunomodulation and targeted therapies against non-immune-related pathways may enhance the efficacy of steroids in this setting, and early predictive and prognostic biomarkers can help identify the subgroup of patients who would likely need treatments other than (or in addition to) generic immunosuppression.

The use of basiliximab-infliximab combination for the treatment of severe gastrointestinal acute GvHD

After allogeneic stem cell transplant, severe grade III-IV gastrointestinal (GI) acute GvHD is associated with significant morbidity and mortality, and generally results in poor outcomes. Salvage therapy for patients who fail steroid therapy is not well defined in the literature. In the current retrospective study, we reviewed our experience with the combination of basiliximab and infliximab in 21 patients with severe, grade III-IV GI acute GvHD of whom 16 met the definition for steroid-refractory disease. The overall response rate was 76%, with 43% CR at a median time of 21 days after beginning treatment. The survival at 1 year was 24%, with most deaths due to complications from GvHD and recurrence of primary disease. All five of the long-term survivors have chronic GvHD. On the basis of a review of the literature, this regimen does not seem to be significantly more effective than other strategies for severe GI GvHD and seems to be worse than the results reported for basiliximab alone. Future studies of single-agent basiliximab and newer agents are required.

Approaches for the prevention of graft-versus-host disease following hematopoietic cell transplantation

Allogeneic hematopoietic cell transplantation (HCT) is an important therapeutic option for malignant and non-malignant diseases, but the more widespread application of the therapy remains limited by the occurrence of graft versus host disease (GVHD). GVHD results from immune-mediated injury by donor immune cells against tissues in the HCT recipient, and can be characterized as acute or chronic depending on the time of onset and site of organ involvement. The majority of efforts have focused on GVHD prevention. Calcineurin inhibitors are the most widely used agents and are included in almost all regimens. Despite current prophylaxis strategies, 40-70% of patients remain at risk for developing GVHD. Herein, we review standard and emerging therapies used in GVHD management.

Cytokines in Graft-versus-Host Disease

Graft-versus-host disease (GVHD) is a complication of allogeneic bone marrow transplantation whereby transplanted naive and marrow-derived T cells damage recipient tissue through similar mechanisms to those that allow destruction of malignant cells, the therapeutic intent of bone marrow transplantation. The manifestations and severity of GVHD are highly variable and are influenced by the proportions of naive cells maturing along regulatory T cell, Th1, Th2, or Th17 phenotypes. This maturation is largely influenced by local cytokines, which, in turn, activate transcription factors and drive development toward a dominant phenotype. In addition, proinflammatory cytokines exert direct effects on GVHD target tissues. Our knowledge of the role that cytokines play in orchestrating GVHD is expanding rapidly and parallels other infective and inflammatory conditions in which a predominant T cell signature is causative of pathology. Because a broad spectrum of cytokine therapies is now routinely used in clinical practice, they are increasingly relevant to transplant medicine.

Biomarker profiling of steroid-resistant acute GVHD in patients after infusion of mesenchymal stromal cells

We performed a prospective phase II study to evaluate clinical safety and outcome in 48 patients with steroid-refractory grade II-IV acute graft-versus-host disease (aGVHD) treated with mesenchymal stromal cells (MSCs). Clinical outcomes were correlated to comprehensive analyses of soluble and cellular biomarkers. Complete resolution (CR) of aGVHD at day 28 (CR-28) occurred in 12 (25%) patients, CR lasting >1 month (CR-B) occurred in 24 (50%) patients. One-year overall survival was significantly improved in CR-28 (75 versus 33%, P=0.020) and CR-B (79 versus 8%, P<0.001) versus non-CR patients. A six soluble biomarker-panel was predictive for mortality (HR 2.924; CI 1.485-5.758) when measured before MSC-administration. Suppression of tumorigenicity 2 (ST2) was only predictive for mortality 2 weeks after but not before MSC-administration (HR 2.389; CI 1.144-4.989). In addition, an increase in immature myeloid dendritic cells associated with decreased mortality (HR 0.554, CI 0.389-0.790). Patients had persisting T-cell responses against defined virus- and leukemia-associated antigens. In conclusion, our data emphasize the need to carefully assess biomarkers in cohorts with homogeneous GVHD treatments. Biomarkers might become an additional valuable component of composite end points for the rapid and efficient testing of novel compounds to decrease lifecycle of clinical testing and improve the success rate of phase II/III trials.

Therapeutic activity of multiple common γ-chain cytokine inhibition in acute and chronic GVHD

The common γ chain (CD132) is a subunit of the interleukin (IL) receptors for IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21. Because levels of several of these cytokines were shown to be increased in the serum of patients developing acute and chronic graft-versus-host disease (GVHD), we reasoned that inhibition of CD132 could have a profound effect on GVHD. We observed that anti-CD132 monoclonal antibody (mAb) reduced acute GVHD potently with respect to survival, production of tumor necrosis factor, interferon-γ, and IL-6, and GVHD histopathology. Anti-CD132 mAb afforded protection from GVHD partly via inhibition of granzyme B production in CD8 T cells, whereas exposure of CD8 T cells to IL-2, IL-7, IL-15, and IL-21 increased granzyme B production. Also, T cells exposed to anti-CD132 mAb displayed a more naive phenotype in microarray-based analyses and showed reduced Janus kinase 3 (JAK3) phosphorylation upon activation. Consistent with a role of JAK3 in GVHD, Jak3(-/-) T cells caused less severe GVHD. Additionally, anti-CD132 mAb treatment of established chronic GVHD reversed liver and lung fibrosis, and pulmonary dysfunction characteristic of bronchiolitis obliterans. We conclude that acute GVHD and chronic GVHD, caused by T cells activated by common γ-chain cytokines, each represent therapeutic targets for anti-CD132 mAb immunomodulation.

Phase 3 clinical trial of steroids/mycophenolate mofetil vs steroids/placebo as therapy for acute GVHD: BMT CTN 0802

Corticosteroids are the accepted primary therapy for acute graft-versus-host disease (GVHD), but durable responses are seen in only about half of the patients. Blood and Marrow Transplant Clinical Trials Network (BMT CTN) 0802, a phase 3 multicenter randomized double-blinded trial, was designed to test whether mycophenolate mofetil (MMF) plus corticosteroids was superior to corticosteroids alone as initial therapy for acute GVHD. Patients with newly diagnosed acute GVHD were eligible if they required systemic therapy. Patients were randomized to receive prednisone with either MMF or placebo. The primary end point was acute or chronic GVHD-free survival at day 56 after initiation of therapy. A futility rule for GVHD-free survival at day 56 was met at a planned interim analysis after 235 patients (of 372) were enrolled: 116 MMF, 119 placebo. Baseline characteristics were well balanced between treatment groups including grade and organ distribution of GVHD. GVHD-free survival at day 56, cumulative incidence of chronic GVHD at 12 months, overall survival, Epstein-Barr virus reactivation, severe, life-threatening infections, relapse at 12 months, and quality of life were similar. The addition of MMF to corticosteroids as initial therapy for acute GVHD does not improve GVHD-free survival compared with corticosteroids alone. This trial was registered at www.clinicaltrials.gov as #NCT01002742.

Current and emerging strategies for the prevention of graft-versus-host disease

Graft-versus-host disease (GVHD) represents the most serious and challenging complication of allogeneic haematopoietic stem-cell transplantation (HSCT). New insights on the role of regulatory T-cells, T cells, and antigen-presenting cells have led to an improved understanding of the pathophysiology of GVHD. However, little progress has been made since the introduction of calcineurin-inhibitor-based regimens in the mid-1980s. Despite standard prophylaxis with these regimens, GVHD still develops in approximately 40-60% of recipients. Thus, there is a need for developing newer approaches to mitigate GVHD, which may facilitate the use of allogeneic HSCT for the treatment of a wider range of haematological cancers. We discuss the rationale, clinical evidence, and outcomes of current (and widely employed) strategies for GVHD prophylaxis, namely calcineurin-inhibitor-based regimens (such as cyclosporine or tacrolimus) combined with methotrexate or mycophenolate mofetil. We assess the clinical evidence for emerging approaches in the prevention of GVHD, including therapies targeting T cells or B cells, the use of mesenchymal stem cells, chemo-cytokine antagonists (such as maraviroc, TNF-α inhibitor, IL-2 receptor antagonist, IL-6 inhibitor), and the use of novel molecular regulators that target multiple cell types simultaneously, including atorvastatin, bortezomib, and epigenetic modulators.

Treatment and management of graft-versus-host disease: improving response and survival

Graft-versus-host disease (GVHD) is a significant cause of morbidity and mortality following allogenic haematopoietic stem-cell transplantation and thus the focus of much ongoing research. Despite considerable advances in our understanding of the pathophysiology, diagnosis and predisposing factors for both acute and chronic forms of the disease, a standardised therapeutic strategy is still lacking. There is good evidence for initial treatment of both acute and chronic forms of the disease with corticosteroid therapy. However, the most effective approach to steroid-refractory disease remains controversial, with current practice based mainly on smaller studies and varying considerably between local institutions. Timely diagnosis, multidisciplinary working and good supportive care, including infection prophylaxis, are clearly important in optimizing response and survival in such patients. It is hoped that in the future systematic research strategies and the identification of novel therapeutic targets may improve outcome further. The following review aims to outline some of the existing options for the treatment and management of acute and chronic GVHD.