Safety and efficacy of rituximab-based first line treatment of chronic GVHD

Long-Term Clinical Outcomes and B Cell Immune Reconstitution Following Allo-HCT With Prophylactic, Post-Transplant Rituximab

Chronic graft-versus-host disease (cGVHD) remains a significant source of morbidity and mortality following allogeneic hematopoietic cell transplantation (HCT). Post-transplant, prophylactic rituximab has successfully decreased cGHVD rates in clinical trials, but the durability of this strategy is uncertain. The long-terms effect of post-HCT B cell depletion on immune reconstitution, B cell function, and infectious complications are also unknown. In this study, we provide 10 yr follow-up and correlative analyses on patients given post-HCT, prophylactic rituximab. The objective of the study is to examine the durability of cGVHD protection as well as the long-term effect of rituximab prophylaxis on protective immune reconstitution, B cell function, and alloantibody formation. We analyzed 35 patients given prophylactic rituximab on phase II clinical trial. Clinical outcomes included cGVHD development, relapse and survival outcomes, and infectious outcomes. Correlative analyses included B cell subset analysis, development of antibodies to infectious antigens, and, for male patients receiving female donor grafts, development of antibodies to HY antigens. To further investigate the effect of rituximab on immune reconstitution and function, we also analyzed 43 similarly transplanted patients who did not receive post- or peri-HCT rituximab as a comparator group. For patients who received rituximab, the 8-yr cumulative incidence of cGHVD and freedom from immunosuppression were 20.0% and 76.2%, respectively. Importantly, no late incidences of cGVHD developed beyond 14 mo post-HCT. Relative to patients who did not receive rituximab, post-HCT rituximab was associated with increased B cell aplasia at 1 yr post-HCT (42.9% versus 11% of patients, P = .037); by 3 yr post-HCT, this aplasia resolved. Patients who received rituximab also had a significantly lower proportion of IgD+/CD38+ transitional B cells at 3 yr post-HCT (78.8% versus 89.9%, P = .039); at 10 yr post-HCT, this percentage remained markedly decreased at 50.7%. Rituximab prophylaxis altered B cell function. In male patients receiving female donor grafts, fewer patients developed HY antibodies at 3 yr post-HCT (20% versus 78%, P = .04). At 10 yr post-HCT, HY antibody production remained decreased at 33%. Rituximab prophylaxis was also associated with significantly lower antibody response to tetanus and EBV infectious antigens as well as lower IgG levels. Despite these changes, post-HCT was not associated with increased infections, although patients who received rituximab required intravenous immunoglobulin (IVIG) supplementation more frequently than those who did not (62.9% versus 32.6% of patients, P = .01). Prior data on the efficacy and feasibility of rituximab prophylaxis are durable, with persistent reduction in cGVHD. Rituximab prophylaxis also results in lasting B cell immunologic changes, with altered B cell subset composition and decreased alloantibody formation. Associated infectious risks were not increased, perhaps mitigated by high IVIG use.

Repurposing of rituximab biosimilars to treat B cell mediated autoimmune diseases

Rituximab, the first monoclonal antibody approved for the treatment of lymphoma, eventually became one of the most popular and versatile drugs ever in terms of clinical application and revenue. Since its patent expiration, and consequently, the loss of exclusivity of the original biologic, its repurposing as an off-label drug has increased dramatically, propelled by the development and commercialization of its many biosimilars. Currently, rituximab is prescribed worldwide to treat a vast range of autoimmune diseases mediated by B cells. Here, we present a comprehensive overview of rituximab repurposing in 115 autoimmune diseases across 17 medical specialties, sourced from over 1530 publications. Our work highlights the extent of its off-label use and clinical benefits, underlining the success of rituximab repurposing for both common and orphan immune-related diseases. We discuss the scientific mechanism associated with its clinical efficacy and provide additional indications for which rituximab could be investigated. Our study presents rituximab as a flagship example of drug repurposing owing to its central role in targeting cluster of differentiate 20 positive (CD20) B cells in 115 autoimmune diseases.

Low-dose rituximab in steroid-refractory chronic graft-versus-host disease

BACKGROUND

Chronic graft-versus-host disease (cGvHD) is a major complication that puts patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) at risk of death or infection. Currently, there is no gold standard for the first-line treatment of patients who do not respond to steroids, and there are several therapeutic options being evaluated in clinical trials for this disease to be used even in the first-line treatment for GvHD. There is evidence of the benefit of rituximab, an anti-CD20 antibody, at a standard dose of 375 mg/m2 weekly in the treatment of steroid-refractory chronic graft-versus disease (SR-cGvHD).

OBJECTIVE

To demonstrate the safety and efficacy of low-dose rituximab in a middle-income center in northeastern Mexico STUDY DESIGN: We report the experience of 26 patients with chronic graft-versus-graft disease who received low-dose rituximab (100 mg weekly for 4 weeks). We utilized the advances in the National Institutes of Health (NIH) criteria for diagnosis, scoring, trial design, and assessment of treatment response.

RESULTS

We obtained a 5-year overall survival of 23.6%, including four patients with complete response. The 1-year event-free survival was 70% for patients with rituximab. During the treatment, there were 3 hospitalizations, and the causes were: immune thrombocytopenia, a parapneumonic effusion, and a cerebral vascular event. The median length of hospital stay was twelve days.

CONCLUSION

A low dose of rituximab is an available and cost-effective option for patients with steroid-refractory cGvHD.

International society for cell & gene therapy stem cell engineering committee: Cellular therapies for the treatment of graft-versus-host-disease after hematopoietic stem cell transplant

BACKGROUND AIMS

Allogeneic hematopoietic stem cell transplant is a curative approach for many malignant and non-malignant hematologic conditions. Despite advances in its prevention and treatment, the morbidity and mortality related to graft-versus-host disease (GVHD) remains. The mechanisms by which currently used pharmacologic agents impair the activation and proliferation of potentially alloreactive T cells reveal pathways essential for the detrimental activities of these cell populations. Importantly, these same pathways can be important in mediating the graft-versus-leukemia effect in recipients transplanted for malignant disease. This knowledge informs potential roles for cellular therapies such as mesenchymal stromal cells and regulatory T cells in preventing or treating GVHD. This article reviews the current state of adoptive cellular therapies focused on GVHD treatment.

METHODS

We conducted a search for scientific literature in PubMed® and ongoing clinical trials in clinicaltrial.gov with the keywords "Graft-versus-Host Disease (GVHD)," "Cellular Therapies," "Regulatory T cells (Tregs)," "Mesenchymal Stromal (Stem) Cells (MSCs)," "Natural Killer (NK) Cells," "Myeloid-derived suppressor cells (MDSCs)," and "Regulatory B-Cells (B-regs)." All the published and available clinical studies were included.

RESULTS

Although most of the existing clinical data focus on cellular therapies for GVHD prevention, there are observational and interventional clinical studies that explore the potential for cellular therapies to be safe modalities for GVHD treatment while maintaining the graft-versus-leukemia effect in the context of malignant diseases. However, there are multiple challenges that limit the broader use of these approaches in the clinical scenario.

CONCLUSIONS

There are many ongoing clinical trials to date with the promise to expand our actual knowledge on the role of cellular therapies for GVHD treatment in an attempt to improve GVHD-related outcomes in the near future.

Monoclonal antibodies used for the management of haematological disorders

INTRODUCTION

Monoclonal antibodies Ab (MoAb) are increasingly becoming part of therapeutic armamentarium for haematologists and haemato-oncologists. This review brings together commonly used antibodies in one place for brevity and novel understanding.

AREAS COVERED

Pubmed and Scopus databases were explored focusing on MoAb in clinical haematological practice. Emphasis was given to current review articles. The data base was searched from 1997 till present. 24 different antibodies, most of which are in use were discussed. Antibodies are used for diverse conditions i.e. malignant and benign haematological conditions, treatment at various phases of stem cell transplantation. These antibodies were used both alone or in combination with various chemotherapy, targeted small molecules or as immunoconjugates. Some of the side effect profiles of these antibodies were common and some were unique. Unusual infections or organ dysfunctions were noted. Improved function of antibodies by protein engineering is also advancing rapidly. Dosage, frequency and route of administration depended on the convenience and condition for which the antibody is used.

EXPERT OPINION

: MoAbs are increasingly used in haematology practice either alone or in combination with other types of therapy for improved out come in various haematological conditions.

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.

Immunometabolic Therapeutic Targets of Graft-versus-Host Disease (GvHD)

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative option in the treatment of aggressive malignant and non-malignant blood disorders. However, the benefits of allo-HSCT can be compromised by graft-versus-host disease (GvHD), a prevalent and morbid complication of allo-HSCT. GvHD occurs when donor immune cells mount an alloreactive response against host antigens due to histocompatibility differences between the donor and host, which may result in extensive tissue injury. The reprogramming of cellular metabolism is a feature of GvHD that is associated with the differentiation of donor CD4+ cells into the pathogenic Th1 and Th17 subsets along with the dysfunction of the immune-suppressive protective T regulatory cells (Tregs). The activation of glycolysis and glutaminolysis with concomitant changes in fatty acid oxidation metabolism fuel the anabolic activities of the proliferative alloreactive microenvironment characteristic of GvHD. Thus, metabolic therapies such as glycolytic enzyme inhibitors and fatty acid metabolism modulators are a promising therapeutic strategy for GvHD. We comprehensively review the role of cellular metabolism in GvHD pathogenesis, identify candidate therapeutic targets, and describe potential strategies for augmenting immunometabolism to ameliorate GvHD.

Phase 2 multicenter trial of ofatumumab and prednisone as initial therapy of chronic graft-vs-host disease

Ofatumumab with glucocorticoid therapy for cGVHD resulted in 62.5% ORR at 6 months and 53% FFS at 12 months.

Safety was observed with ofatumumab plus glucocorticoid for initial therapy.

Standard initial therapy of chronic graft vs. host disease (cGVHD) with glucocorticoids results in suboptimal response. Safety and feasibility of therapy with ofatumumab (1000 mg IV on days 0 and 14) and prednisone (1 mg/kg/day) was previously established in our phase I trial (n = 12). We now report the mature results of the phase II expansion of the trial (n = 38). The overall NIH severity of cGVHD was moderate (63%) or severe (37%) with 74% of all patients affected by the overlap subtype of cGVHD and 82% by prior acute cGVHD. The observed 6 month clinician-reported and 2014 NIH-defined overall response rates (ORR = complete + partial response [CR/PR]) of 62.5% (1-sided lower 90% confidence interval=51.5%) were not superior to pre-specified historic benchmark of 60%. Post-hoc comparison of 6 month NIH response suggested benefit compared to more contemporaneous NIH-based benchmark of 48.6% with frontline sirolimus/prednisone (CTN 0801 trial). Baseline cGVHD features (organ involvement, severity, initial immune suppression agents) were not significantly associated with 6-month ORR. The median time to initiation of second-line therapy was 5.4 months (range 0.9-15.1 months). Failure-free survival (FFS) was 64.2% (95% CI 46.5-77.4%) at 6 months and 53.1% (95% CI 35.8-67.7%) at 12 months, whereas FFS with CR/PR at 12 months of 33.5% exceeded a benchmark of 15% in post-hoc analysis, and was associated with greater success in steroid discontinuation by 24 months (odds ratio 8 (95% CI 1.21-52.7). This single-arm phase II trial demonstrated acceptable safety and potential efficacy of the upfront use of ofatumumab in combination with prednisone in cGVHD.  This trial was registered at www.clinicaltrials.gov as #NCT01680965.

The promise and perils of immunotherapy

Advances in understanding the ways in which the immune system fails to control tumor growth or prevent autoimmunity have led to the development of powerful therapeutic strategies to treat these diseases. In contrast to conventional therapies that have a broadly suppressive effect, immunotherapies are more akin to targeted therapies because they are mechanistically driven and are typically developed with the goal of "drugging" a specific underlying pathway or phenotype. This means that their effects and toxicities are, at least in theory, more straightforward to anticipate. The development of functionalized antibodies, genetically engineered T cells, and immune checkpoint inhibitors continues to accelerate, illuminating new biology and bringing new treatment to patients. In the following sections, we provide an overview of immunotherapeutic concepts, highlight recent advances in the field of immunotherapies, and discuss controversies and future directions, particularly as these pertain to hematologic oncology or blood-related diseases. We conclude by illustrating how original research published in this journal fits into and contributes to the overall framework of advances in immunotherapy.

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.