Phase 1 clinical trial evaluating abatacept in patients with steroid-refractory chronic graft-versus-host disease

The Application of Umbilical Cord Blood-derived Platelet Gel for Skin Ulcers Associated With Chronic Graft-Versus-Host Disease in Pediatrics: A Randomized Trial

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative strategy against a variety of malignant and nonmalignant disorders. However, acute and chronic graft-versus-host disease (aGVHD and cGVHD, respectively) commonly complicate this approach, culminating in substantial morbidities and mortalities. The integumentary system is the preponderant organ involved in cGVHD, and its response to existing treatments, including well-versed immunosuppressants and novel targeted therapies, is not desirable. Despite the rarity, ulcers of sclerotic skin cGVHD are treatment-refractory and associated with significant morbidities and an exaggerated risk of infectious complications. Platelet-rich plasma (PRP) and its derivatives are endowed with growth factors and proangiogenic molecules and hold regenerative potential. This study aimed to assess the safety and efficacy of the application of platelet gel-containing dressing against ulcerative skin cGVHD in pediatric patients. This randomized trial is conducted at the hematopoietic stem cell transplantation unit of the Children's Medical Center Hospital in Tehran, Iran. Twenty-one pediatric patients (aged between 5 and 15 years) were initially enrolled, and 16 met the inclusion criteria. All cases (4 females) were recipients of allo-HSCT who had been complicated with symmetrically or near-symmetrically ulcerative sclerotic skin cGVHD. Fresh umbilical cord blood (UCB) was obtained from healthy donors and underwent centrifugation using a novel PRP preparation kit in a single-step process. Platelet gel was produced by adding thrombin to the isolated buffy coat layer. Two similar ulcers of each patient were randomized to receive either conventional dressing or platelet gels up to 6 times. At each time point evaluation, ulcer size and its relative reduction compared to the basal size were recorded. Included patients received a total of 80 platelet gel-containing dressings. While the mean sizes of randomized ulcers at the beginning of the study were similar, their differences became significant 15 days after the initiation of intervention (P = .019). In addition, the mean reduction in the ulcers' surface area (in comparison to their baseline values) was significantly higher for the intervention arm at all evaluation points (P = .001 for day 5 and P < .001 for subsequent time points). At the end of the trial, the number of ulcers with a more than 50% reduction in size was 14 (87.5%) in the intervention arm (including 6 completely healed ulcers) versus 1 (6.25%, which was not completely healed) in the control arm (P < .001). None of the patients exhibited any localized or systemic treatment-related adverse events. In this study, using a relatively large number of cases, we showed that UCB-derived platelet gel is a safe, feasible, and effective curative approach for skin ulcers of sclerotic skin cGVHD in pediatric patients. Designing upcoming trials on the efficacy of this therapeutic approach for ocular, mucosal, and acute skin GVHD is prudent. Retrospectively registered at the Iranian Registry of Clinical Trials (registration number IRCT20190101042197N1) on August 24, 2020.

A personalized, organ-based approach to the treatment of chronic steroid-refractory graft-versus-host disease

Chronic graft-versus-host-disease (cGvHD) remains the leading cause of morbidity among transplant recipients. The efficacy of second-line treatments varies widely based on many factors, including wide differences in the organ overall response-rate response and in the current era where multiple agents are approved, and optimal sequencing of drugs based on organ ORR is unknown. We aimed to evaluate outcomes based on ORRs to the most common agents for the treatment of steroid-refractory/steroid-dependent cGvHD by conducting a systematic literature review. A total of 387 studies were evaluated for the ORRs of 12 cGvHD treatments. The highest skin ORR was observed to be 77% though some agents had an acceptable ORR. Most agents had an ocular response ranging from 17 to 50% Some agents resulted in a GI ORR of ≥88%. Rituximab showed the best response for musculoskeletal-GvHD. In the case of lung-GvHD (bronchiolitis obliterans syndrome [BOS]), negligible response was observed in patients treated with various agents. No clinically meaningful responses to treatments were reported for genital-GvHD. Most GvHD trials are focused on the ORR and partial response rates (PRR). The evidence for optimal agents for each organ is limited, and therefore, our study results are striking for differences in organ-ORR yields for a clinically meaningful difference. Thus, a personalized organ-based approach to the selection of therapeutic agents in cGvHD could result in favorable outcomes.

Updates in chronic graft-versus-host disease management

Chronic graft-versus-host disease (cGvHD) remains the most important long-term complication of allogeneic hematopoietic cell transplantation (allo-HCT), but the field has seen significant changes in the last decade. Remarkable advances in the understanding of the biological pathways of cGvHD, lead to the development of targeted therapy with novel drugs thereby minimizing the exposure to harmful corticosteroids, preserving function and mobility, preventing disability, and improving quality of life (QoL) and overall survival (OS). Steroid-refractory cGvHD management has recently experienced significant improvement since ibrutinib and ruxolitinib were approved for patients that failed at least one line of treatment and belumosudil for patients that failed two lines. These recently approved drugs will be discussed in this review, along with perspectives regarding cGVHD management and additional promising drug in development.

Chronic GvHD NIH Consensus Project Biology Task Force: evolving path to personalized treatment of chronic GvHD

Chronic graft-versus-host disease (cGvHD) remains a prominent barrier to allogeneic hematopoietic stem cell transplantion as the leading cause of nonrelapse mortality and significant morbidity. Tremendous progress has been achieved in both the understanding of pathophysiology and the development of new therapies for cGvHD. Although our field has historically approached treatment from an empiric position, research performed at the bedside and bench has elucidated some of the complex pathophysiology of cGvHD. From the clinical perspective, there is significant variability of disease manifestations between individual patients, pointing to diverse biological underpinnings. Capitalizing on progress made to date, the field is now focused on establishing personalized approaches to treatment. The intent of this article is to concisely review recent knowledge gained and formulate a path toward patient-specific cGvHD therapy.

Graft-versus-host disease: teaching old drugs new tricks at less cost

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic stem cell transplantation (SCT). Currently, more patients can receive SCT. This is attributed to the use of reduced intensity regimens and the use of different GVHD prophylaxis that breaks the barrier of human leukocyte antigen, allowing an increase in the donor pool. Once an area with relatively few clinical trial options, there has been an increase in interest in GVHD prophylaxis and treatment, which has led to many US Food and Drug Administration (FDA) approvals. Although there is considerable excitement over novel therapies, many patients may not have access to them due to geographical or other resource constraints. In this review article, we summarize the latest evidence on how we can continue to repurpose drugs for GVHD prophylaxis and treatment. Drugs covered by our review include those that have been FDA approved for other uses for at least 15 years (since 2008); thus, they are likely to have generic equivalents available now or in the near future.

The delicate balance of graft versus leukemia and graft versus host disease after allogeneic hematopoietic stem cell transplantation

INTRODUCTION

The curative basis of allogeneic hematopoietic stem cell transplantation (HSCT) relies in part upon the graft versus leukemia (GvL) effect, whereby donor immune cells recognize and eliminate recipient malignant cells. However, alloreactivity of donor cells against recipient tissues may also be deleterious. Chronic graft versus host disease (cGvHD) is an immunologic phenomenon wherein alloreactive donor T cells aberrantly react against host tissues, leading to damaging inflammatory symptoms.

AREAS COVERED

Here, we discuss biological insights into GvL and cGvHD and strategies to balance the prevention of GvHD with maintenance of GvL in modern HSCT.

EXPERT OPINION/COMMENTARY

Relapse remains the leading cause of mortality after HSCT with rates as high as 40% for some diseases. GvHD is a major cause of morbidity after HSCT, occurring in up to half of patients and responsible for 15-20% of deaths after HSCT. Intriguingly, the development of chronic GvHD may be linked to lower relapse rates after HSCT, suggesting that GvL and GvHD may be complementary sides of the immunologic foundation of HSCT. The ability to fine tune the balance of GvL and GvHD will lead to improvements in survival, relapse rates, and quality of life for patients undergoing HSCT.

Role of abatacept in the prevention of graft-versus-host disease: current perspectives

Administration of abatacept following transplantation has been reported to inhibit graft rejection and graft-versus-host-disease (GvHD) in mouse models associated with allogeneic hematopoietic stem cell transplant (HSCT). This strategy has recently been adopted in clinical practice for GvHD prevention in human allogeneic HSCT and offers a unique approach to optimizing GvHD prophylaxis following alternative donor HSCTs. When combined with calcineurin inhibitors and methotrexate, abatacept had shown to be safe and effective in preventing moderate to severe acute GvHD in myeloablative HSCT using human leukocyte antigen (HLA) unrelated donors. Equivalent results are being reported in recent studies using alternative donors, in reduced-intensity conditioning HSCT and nonmalignant disorders. These observations have led to hypothesizing that even in the setting of increasing donor HLA disparity, abatacept when given with traditional GvHD prophylaxis does not worsen general outcomes. In addition, in limited studies, abatacept have being protective against the development of chronic GvHD through extended dosing and in the treatment of steroid-refractory chronic GvHD. This review summarized all the limited reports of this novels approach in the HSCT setting.

Monoclonal antibody-mediated immunosuppression enables long-term survival of transplanted human neural stem cells in mouse brain

BACKGROUND

As the field of stem cell therapy advances, it is important to develop reliable methods to overcome host immune responses in animal models. This ensures survival of transplanted human stem cell grafts and enables predictive efficacy testing. Immunosuppressive drugs derived from clinical protocols are frequently used but are often inconsistent and associated with toxic side effects. Here, using a molecular imaging approach, we show that immunosuppression targeting costimulatory molecules CD4 and CD40L enables robust survival of human xenografts in mouse brain, as compared to conventional tacrolimus and mycophenolate mofetil.

METHODS

Human neural stem cells were modified to express green fluorescent protein and firefly luciferase. Cells were implanted in the fimbria fornix of the hippocampus and viability assessed by non-invasive bioluminescent imaging. Cell survival was assessed using traditional pharmacologic immunosuppression as compared to monoclonal antibodies directed against CD4 and CD40L. This paradigm was also implemented in a transgenic Alzheimer's disease mouse model.

RESULTS

Graft rejection occurs within 7 days in non-immunosuppressed mice and within 14 days in mice on a traditional regimen. The addition of dual monoclonal antibody immunosuppression extends graft survival past 7 weeks (p < .001) on initial studies. We confirm dual monoclonal antibody treatment is superior to either antibody alone (p < .001). Finally, we demonstrate robust xenograft survival at multiple cell doses up to 6 months in both C57BL/6J mice and a transgenic Alzheimer's disease model (p < .001). The dual monoclonal antibody protocol demonstrated no significant adverse effects, as determined by complete blood counts and toxicity screen.

CONCLUSIONS

This study demonstrates an effective immunosuppression protocol for preclinical testing of stem cell therapies. A transition towards antibody-based strategies may be advantageous by enabling stem cell survival in preclinical studies that could inform future clinical trials.

Management of Chronic Graft-vs.-Host Disease in Children and Adolescents With ALL: Present Status and Model for a Personalised Management Plan

Herein we review current practice regarding the management of chronic graft-vs.-host disease (cGvHD) in paediatric patients after allogeneic haematopoietic stem cell transplantation (HSCT) for acute lymphoblastic leukaemia (ALL). Topics covered include: (i) the epidemiology of cGvHD; (ii) an overview of advances in our understanding cGvHD pathogenesis; (iii) current knowledge regarding risk factors for cGvHD and prevention strategies complemented by biomarkers; (iii) the paediatric aspects of the 2014 National Institutes for Health-defined diagnosis and grading of cGvHD; and (iv) current options for cGvHD treatment. We cover topical therapy and newly approved tyrosine kinase inhibitors, emphasising the use of immunomodulatory approaches in the context of the delicate counterbalance between immunosuppression and immune reconstitution as well as risks of relapse and infectious complications. We examine real-world approaches of response assessment and tapering schedules of treatment. Furthermore, we report on the optimal timepoints for therapeutic interventions and changes in relation to immune reconstitution and risk of relapse/infection. Additionally, we review the different options for anti-infectious prophylaxis. Finally, we put forth a theory of a holistic view of paediatric cGvHD and its associated manifestations and propose a checklist for individualised risk evaluation with aggregated considerations including site-specific cGvHD evaluation with attention to each individual's GvHD history, previous medical history, comorbidities, and personal tolerance and psychosocial circumstances. To complement this checklist, we present a treatment algorithm using representative patients to inform the personalised management plans for patients with cGvHD after HSCT for ALL who are at high risk of relapse.

The clinical landscape of chronic graft-versus-host disease management in 2021

Chronic graft-versus-host disease (cGVHD) is an important systemic complication of allogeneic haematopoietic stem cell transplantation with heterogeneous, multi-organ involvement that can lead to increased morbidity and mortality. Despite significant advances in understanding the complex pathophysiology driving the disease, curative treatment options remain suboptimal. The past decade, however, has seen much growth in collaborative research efforts and standardization of criteria for clinical trials that have led to discovery of several new second-line therapies in cGVHD. The key to successful cGVHD control and management includes a comprehensive and sustained multidisciplinary effort with emphasis on ancillary and supportive care for these patients. The focus of this review is to summarize the new developments in systemic, organ-specific, and topical treatments in the management of cGVHD that emerged since the 2014 NIH consensus conference.

Graft-versus-host Disease Prophylaxis With Abatacept Reduces Severe Acute Graft-versus-host Disease in Allogeneic Hematopoietic Stem Cell Transplant for Beta-thalassemia Major With Busulfan, Fludarabine, and Thiotepa

BACKGROUND

We hypothesized that the addition of 4 doses of abatacept to our standard acute graft-versus-host disease (GVHD) prophylaxis would reduce the incidence of day +100 severe acute GVHD in children with transfusion-dependent beta-thalassemia major undergoing a myeloablative allogeneic hematopoietic stem cell transplant (HSCT), without impacting engraftment.

METHODS

Twenty-four children with beta-thalassemia major received abatacept at a dose of 10 mg/kg intravenously on days -1, +5, +14, and +28 after HSCT in addition to calcineurin inhibitors and methylprednisolone. Outcomes were compared to 8 beta-thalassemia patients who received standard acute GVHD prophylaxis.

RESULTS

There was no difference in engraftment between the 2 groups. No patient had grades III-IV acute GVHD by day +100 in the abatacept cohort compared with 50% in the standard acute GVHD prophylaxis group (P = 0.001). Viral reactivation occurred in 5 children in the standard acute GVHD cohort and in 20 children in the abatacept cohort (P = 0.2). Thalassemia-free survival after HSCT was 100% in the abatacept cohort compared to 62.5% in the standard cohort at last follow-up (P = 0.007).

CONCLUSIONS

Adding abatacept to our routine GVHD prophylaxis reduced the incidence of day +100 severe acute GVHD without impacting engraftment or survival.

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.

Current Concepts and Advances in Graft-Versus-Host Disease Immunology

Worldwide, each year over 30,000 patients undergo an allogeneic hema-topoietic stem cell transplantation with the intent to cure high-risk hematologic malignancy, immunodeficiency, metabolic disease, or a life-threatening bone marrow failure syndrome. Despite substantial advances in donor selection and conditioning regimens and greater availability of allograft sources, transplant recipients still endure the morbidity and mortality of graft-versus-host disease (GVHD). Herein, we identify key aspects of acute and chronic GVHD pathophysiology, including host/donor cell effectors, gut dysbiosis, immune system and cytokine imbalance, and the interface between inflammation and tissue fibrosis. In particular, we also summarize the translational application of this heightened understanding of immune dysregulation in the design of novel therapies to prevent and treat GVHD.

Graft Versus Host Disease Associated with Immune Checkpoint Inhibitors: A Pharmacovigilance Study and Systematic Literature Review

Background: In patients with allogenic hematopoietic stem cell transplantation (allo-HSCT), immune-checkpoint inhibitors (ICI) are used to treat malignancy recurrence. However, ICI are also associated with graft vs. host disease (GVHD). In this pharmacovigilance analysis, we aimed to characterize cases of GVHD associated with ICI, drawn from the World Health Organization pharmacovigilance database, VigiBase®, and from literature. Methods: We performed VigiBase® query of cases of GVHD associated with ICI. These cases were combined with those of literature, not reported in VigiBase®. The Bayesian estimate of disproportionality analysis, the information component, was considered significant if its 95% credibility interval lower bound was positive; denoting a significant association between GVHD and the suspected ICI. Time to onset between ICI and GVHD onset and subsequent mortality were assessed. Results: Disproportionality analysis yielded 93 cases of GVHD associated with ICI (61.8% men, median age 38 [interquartile range = 27; 50] years). Cases were mostly associated with nivolumab (53/93, 57.0%), pembrolizumab (23/93, 24.7%) and ipilimumab (12/93, 12.9%) monotherapies. GVHD events occurred after 1 [1; 5.5] injection of ICI, with a time to onset of 35 [IQR = 14; 176] days. Immediate subsequent mortality after GVHD was 24/93, 25.8%. There was no significant difference in mortality depending on the molecule (p = 0.41) or the combination regimen (combined vs. monotherapy, p = 0.60). Previous history of GVHD was present in 11/18, 61.1% in cases reported in literature. Conclusion: In this worldwide pharmacovigilance study, disproportionality yielded significant association between GVHD and ICI, with subsequent mortality of 25.8%. Previous history of GVHD was reported in more than half of cases. Clinicaltrials.gov identifier: NCT03492242.

Monogenic Immune Diseases Provide Insights Into the Mechanisms and Treatment of Chronic Graft-Versus-Host Disease

Chronic graft-versus-host disease (GvHD) has become a leading cause of morbidity and mortality following allogeneic hematopoietic stem cell transplantation (HSCT) and can burden patients with devastating and lifelong health effects. Our understanding of the pathogenic mechanisms underlying chronic GvHD remains incomplete and this lack of understanding is reflected by lack of clear therapeutic approaches to steroid refractory disease. Observations predominantly from mouse models and human correlative studies currently support a three phase model for the initiation and development of chronic GvHD: 1) early inflammation and tissue damage triggers the innate immune system. This leads to inflammatory cytokine/chemokine patterns that recruit effector immune cell populations; 2) chronic inflammation causes the loss of central and peripheral tolerance mechanisms leading to emergence of pathogenic B and T cell populations that promote autoimmune and alloimmune reactions; 3) the dysregulated immunity causes altered macrophage polarization, aberrant tissue repair leading to scarring and end organ fibrosis. This model has led to the evaluation of many new therapies aimed at limiting inflammation, targeting dysregulated signaling pathways and restoring tolerance mechanisms. However, chronic GvHD is a multisystem disease with complex clinical phenotypes and it remains unclear as to which cluster of patients will respond best to specific therapeutic strategies. However, it is possible to gain novel insights from immune-related monogenic diseases. These diseases either share common clinical manifestations, replicate steps from the three phase chronic GvHD model or serve as surrogates for perfectly targeted drugs being investigated in chronic GvHD therapy. In this review, we will summarize the evidence from these monogenic immune related diseases that provide insight into pathogenic pathways in chronic GvHD, rationales for current therapies and novel directions for future drug discovery.

Abatacept as salvage therapy in chronic graft-versus-host disease-a retrospective analysis

The immunomodulatory fusion protein abatacept has recently been investigated for the treatment of steroid-refractory chronic graft-versus-host disease (cGvHD) in a phase 1 clinical trial. We analyzed the safety and efficacy of abatacept for cGvHD therapy in a retrospective study with 15 patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) and received abatacept for cGvHD with a median age of 49 years. Grading was performed as part of the clinical routine according to the National Institute of Health’s (NIH) consensus criteria at initiation of abatacept and 1, 3, 6, 9 and 12 months thereafter. The median time of follow-up was 191 days (range 55–393 days). Best overall response rate (ORR) was 40%. In particular, patients with bronchiolitis obliterans syndrome showed significant clinical improvement and durable responses following abatacept treatment with a response rate of 89% based on improvement in lung severity score (n = 6) or stabilized lung function (n = 4) or both (n = 3). Infectious complications CTCAE °III or higher were observed in 3/15 patients. None of the patients relapsed from the underlying malignancy. Thus, abatacept appears to be a promising treatment option for cGvHD, in particular for patients with lung involvement. However, further evaluation within a phase 2 clinical trial is required.

Phase II Trial of Costimulation Blockade With Abatacept for Prevention of Acute GVHD

PURPOSE

Severe (grade 3-4) acute graft-versus-host disease (AGVHD) is a major cause of death after unrelated-donor (URD) hematopoietic cell transplant (HCT), resulting in particularly high mortality after HLA-mismatched transplantation. There are no approved agents for AGVHD prevention, underscoring the critical unmet need for novel therapeutics. ABA2 was a phase II trial to rigorously assess safety, efficacy, and immunologic effects of adding T-cell costimulation blockade with abatacept to calcineurin inhibitor (CNI)/methotrexate (MTX)-based GVHD prophylaxis, to test whether abatacept could decrease AGVHD.

METHODS

ABA2 enrolled adults and children with hematologic malignancies under two strata: a randomized, double-blind, placebo-controlled stratum (8/8-HLA-matched URD), comparing CNI/MTX plus abatacept with CNI/MTX plus placebo, and a single-arm stratum (7/8-HLA-mismatched URD) comparing CNI/MTX plus abatacept versus CNI/MTX CIBMTR controls. The primary end point was day +100 grade 3-4 AGVHD, with day +180 severe-AGVHD-free-survival (SGFS) a key secondary end point. Sample sizes were calculated using a higher type-1 error (0.2) as recommended for phase II trials, and were based on predicting that abatacept would reduce grade 3-4 AGVHD from 20% to 10% (8/8s) and 30% to 10% (7/8s). ABA2 enrolled 142 recipients (8/8s, median follow-up = 716 days) and 43 recipients (7/8s, median follow-up = 708 days).

RESULTS

In 8/8s, grade 3-4 AGVHD was 6.8% (abatacept) versus 14.8% (placebo) (P = .13, hazard ratio = 0.45). SGFS was 93.2% (CNI/MTX plus abatacept) versus 82% (CNI/MTX plus placebo, P = .05). In the smaller 7/8 cohort, grade 3-4 AGVHD was 2.3% (CNI/MTX plus abatacept, intention-to-treat population), which compared favorably with a nonrandomized matched cohort of CNI/MTX (30.2%, P < .001), and the SGFS was better (97.7% v 58.7%, P < .001). Immunologic analysis revealed control of T-cell activation in abatacept-treated patients.

CONCLUSION

Adding abatacept to URD HCT was safe, reduced AGVHD, and improved SGFS. These results suggest that abatacept may substantially improve AGVHD-related transplant outcomes, with a particularly beneficial impact on HLA-mismatched HCT.

Steroid-refractory chronic graft-versus-host disease: treatment options and patient management

Chronic graft-versus-host disease (cGVHD) is one of the major causes of late mortality after allogenic hematopoietic stem cell transplantation. Moderate-to-severe cGVHD is associated with poor health-related quality of life and substantial disease burden. While corticosteroids with or without calcineurin inhibitors comprise the first-line treatment option, the prognosis for patients with steroid-refractory cGVHD (SR-cGVHD) remains poor. The mechanisms underlying steroid resistance are unclear, and there are no standard second-line treatment guidelines for patients with SR-cGVHD. In this review, we provide an overview on current treatment options of cGVHD and use a series of theoretical case studies to elucidate the rationale of choices of second- and third-line treatment options for patients with SR-cGVHD based on individual patient profiles.

New Approaches for the Treatment of Chronic Graft-Versus-Host Disease: Current Status and Future Directions

Chronic graft-versus-host disease (cGvHD) is a severe complication of allogeneic hematopoietic stem cell transplantation that affects various organs leading to a reduced quality of life. The condition often requires enduring immunosuppressive therapy, which can also lead to the development of severe side effects. Several approaches including small molecule inhibitors, antibodies, cytokines, and cellular therapies are now being developed for the treatment of cGvHD, and some of these therapies have been or are currently tested in clinical trials. In this review, we discuss these emerging therapies with particular emphasis on tyrosine kinase inhibitors (TKIs). TKIs are a class of compounds that inhibits tyrosine kinases, thereby preventing the dissemination of growth signals and activation of key cellular proteins that are involved in cell growth and division. Because they have been shown to inhibit key kinases in both B cells and T cells that are involved in the pathophysiology of cGvHD, TKIs present new promising therapeutic approaches. Ibrutinib, a Bruton tyrosine kinase (Btk) inhibitor, has recently been approved by the Food and Drug Administration (FDA) in the United States for the treatment of adult patients with cGvHD after failure of first-line of systemic therapy. Also, Janus Associated Kinases (JAK1 and JAK2) inhibitors, such as itacitinib (JAK1) and ruxolitinib (JAK1 and 2), are promising in the treatment of cGvHD. Herein, we present the current status and future directions of the use of these new drugs with particular spotlight on their targeting of specific intracellular signal transduction cascades important for cGvHD, in order to shed some light on their possible mode of actions.

B cell modulation strategies in the improvement of transplantation outcomes

Successful transplantation outcome is the final goal in most end stage and nonfunctional organs; however, despite using different therapeutic strategies, antibody-mediated rejection is still a big obstacle. B cells have a key role in transplant rejection by several functions, such as antibody production, antigen presenting, contribution in T cell activation, forming the germinal center, and tertiary lymphoid organs. Therefore, B cells modulation seems to be very crucial in transplant outcome. A double-edged sword function is considered for B cells during transplantation; On the one hand, antibody production against the transplanted organ induces antibody-mediated rejection. On the other hand, IL10 production by regulatory B (Breg) cells induces graft tolerance. Nowadays, several monoclonal antibodies (mAb) are available for B cell modulation that are routinely used in transplant recipients, among which rituximab (anti-CD20 mAb) act in eliminating B cells. However, there are some other monoclonal antibodies, such as epratuzumab and Inotuzumab ozogamicin (IO), which exert anti-CD22 activity, resulting in disruption of B cell functions and induction of tolerance in autoimmune disease or B cell malignancies; that notwithstanding, these mAbs have not yet been tried in transplantation. In this review, we focus on different methods for modulating the activity of B cells as well as induction of Breg cells, aiming to prevent the allograft rejection.

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.

The Interplay Between the Genetic and Immune Landscapes of AML: Mechanisms and Implications for Risk Stratification and Therapy

AML holds a unique place in the history of immunotherapy by virtue of being among the first malignancies in which durable remissions were achieved with "adoptive immunotherapy," now known as allogeneic stem cell transplantation. The successful deployment of unselected adoptive cell therapy established AML as a disease responsive to immunomodulation. Classification systems for AML have been refined and expanded over the years in an effort to capture the variability of this heterogeneous disease and risk-stratify patients. Current systems increasingly incorporate information about cytogenetic alterations and genetic mutations. The advent of next generation sequencing technology has enabled the comprehensive identification of recurrent genetic mutations, many with predictive power. Recurrent genetic mutations found in AML have been intensely studied from a cell intrinsic perspective leading to the genesis of multiple, recently approved targeted therapies including IDH1/2-mutant inhibitors and FLT3-ITD/-TKD inhibitors. However, there is a paucity of data on the effects of these targeted agents on the leukemia microenvironment, including the immune system. Recently, the phenomenal success of checkpoint inhibitors and CAR-T cells has re-ignited interest in understanding the mechanisms leading to immune dysregulation and suppression in leukemia, with the objective of harnessing the power of the immune system via novel immunotherapeutics. A paradigm has emerged that places crosstalk with the immune system at the crux of any effective therapy. Ongoing research will reveal how AML genetics inform the composition of the immune microenvironment paving the way for personalized immunotherapy.

Review of Graft-Versus-Host Disease

Graft-versus-host disease (GVHD) is an adverse immunologic phenomenon following allogenic hematopoietic stem cell transplant. Cutaneous manifestations are the earliest and most common presentation of the disease. This article describes the pathophysiology, clinical presentation, diagnosis, and treatment options available for acute and chronic GVHD. Acute and chronic GVHD result from an initial insult triggering an exaggerated inflammatory cascade. Clinical presentation for cutaneous acute GVHD is limited to maculopapular rash and oral mucosal lesions, whereas chronic GVHD can also include nail, scalp, and genitalia changes. Diagnosis is often made clinically and supported by biopsy, laboratory and radiology findings.

Hypertension, Anxiety, and Blood-Brain Barrier Permeability Are Increased in Postpartum Severe Preeclampsia/Hemolysis, Elevated Liver Enzymes, and Low Platelet Count Syndrome Rats

Hypertension and inflammation during pregnancy are suggested to contribute to the development of postpartum depression and anxiety. Using a rat model of severe preeclampsia and hemolysis, elevated liver enzymes, and low platelet count syndrome, which displays both hypertension and inflammation during pregnancy, we evaluated whether rats were prone to develop depression or anxiety in the postpartum period. On gestational day 12, miniosmotic pumps infusing sFlt-1 (soluble fms-like tyrosine kinase-1) and sEng (soluble endoglin) were placed into rats, a subset of these rats was infused with 2 mg/kg of Orencia (abatacept) the following day to determine whether immune suppression via T-cell depletion prevented any changes in maternal depression or anxiety-like behavior. All rats, including normal pregnant (NP) controls, delivered between gestational days 21 and 22. Postpartum severe preeclamptic rats buried significantly more marbles compared with NP rats ( P=0.002) and Orencia-treated rats ( P=0.05). Severe preeclamptic rats spent significantly more time in closed arms of the elevated plus maze compared with NP rats ( P=0.009) and Orencia-treated rats ( P=0.05). Severe preeclamptic rats were hypertensive compared with NP ( P=0.03) and Orencia-treated rats ( P=0.01). Finally, severe preeclamptic rats had increased blood-brain barrier permeability compared with NP rats ( P=0.03), which was reversed in Orencia-treated rats ( P=0.008). These results suggest that severe preeclampsia/hemolysis, elevated liver enzymes, and low platelet count syndrome during pregnancy contributes to an increase in anxiety-like behavior, blood-brain barrier permeability, and hypertension in the postpartum. The current results suggest that T-cell suppression during pregnancy can also help prevent chronic hypertension and increased anxiety in the postpartum period.