Anti-CD20 monoclonal antibody treatment in 6 patients with therapy-refractory chronic graft-versus-host disease

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.

Hepatic graft-versus-host disease: what we know, when to biopsy, and how to diagnose

Graft-versus-host disease (GVHD) is one of the serious complications that may develop after hematopoietic cell transplantation (HCT), for hematologic malignancies, solid organ transplantation, and other hematologic disorders. GVHD develops due to T lymphocytes present in the graft attacking the host antigens, which results in tissue damage. A significant number of HCT patients develop acute or chronic GVHD, which may affect multiple organs including the liver. The diagnosis of hepatic GVHD (hGVHD) is challenging as many other conditions in HCT patients may lead to liver dysfunction. Particularly challenging among the various conditions that give rise to liver dysfunction is differentiating sinusoidal obstruction syndrome and drug-induced liver injury (DILI) from hGVHD on clinical grounds and laboratory tests. Despite the minimal risks involved in performing a liver biopsy, the information gleaned from the histopathologic changes may help in the management of these very complex patients. There is a spectrum of histologic features found in hGVHD, and most involve histopathologic changes affecting the interlobular bile ducts. These include nuclear and cytoplasmic abnormalities including dysmorphic bile ducts, apoptosis, and cholangiocyte necrosis, among others. The hepatitic form of hGVHD typically shows severe acute hepatitis. With chronic hGVHD, there is progressive bile duct loss and eventually fibrosis. Accurate diagnosis of hGVHD is paramount so that timely treatment and management can be initiated. Techniques to prevent and lower the risk of GVHD from developing have recently evolved. If a diagnosis of acute GVHD is made, the first-line of treatment is steroids. Recurrence is common and steroid resistance or dependency is not unusual in this setting. Second-line therapies differ among institutions and have not been uniformly established. The development of GVHD, particularly hGVHD, is associated with increased morbidity and mortality.

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.

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.

Biologics in Dermatology: Off-Label Indications

Skin and subcutaneous diseases affect millions of people worldwide, causing significant morbidity. Biologics are becoming increasingly useful for the treatment of many skin diseases, particularly as alternatives for patients who have failed to tolerate or respond to conventional systemic therapies. Biological therapies provide a targeted approach to treatment through interaction with specific components of the underlying immune and inflammatory disease processes. Advances in the understanding of disease pathophysiology for inflammatory skin diseases and in drug development have ushered in biologic therapies in dermatology. Biologic therapies are molecules that target specific proteins implicated in immune-mediated disease. This review article highlights the increasing evidence base for biologics in dermatology for off-label use.

Modifying Graft-versus-Host Disease in a Humanized Mouse Model by Targeting Macrophages or B-Cells

Humanized mouse models can well be modified to study specific aspects of Graft-versus-Host Disease (GvHD). This paper shows the results of both macrophage depletion and (early) B-cell depletion in a humanized mouse model using RAG2^-/- γc^-/- mice injected with HuPBMCs. Macrophage depletion showed a significant decrease in survival and also lead to a change in the histomorphology of the xenogeneic reaction. Higher levels of infiltrating B-cells were observed in various organs of mice depleted for macrophages. With (early) B-cell depletion using Rituximab, a clear improvement on clinical symptoms was observed, even when probably only inactivated B-cells were deleted. However, the histological examinations only showed a significant morphological effect on liver fibrosis. This may be related to a difference in the mRNA levels of TGF-β. Also, lower mRNA levels of Tregs in some organs were observed after Rituximab treatment, which contradicts that a higher number of Tregs would always be related to less severe GvHD. Our data show that both macrophage depletion and (early) B-cell depletion in a xenogeneic mouse model can influence the clinical, histological, and cytokine production of a GvHD response.

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

Initial therapy of chronic GVHD (cGvHD) has not changed for over three decades, despite limited efficacy and long-term toxicity. We have previously shown in a small pilot study the feasibility of rituximab-based first-line therapy of cGVHD. To better assess safety and efficacy, we now evaluate 69 patients that received rituximab as part of their initial treatment. Median follow-up for surviving patients was 47 (11-81) months. Resolution of cGVHD occurred in 49 patients with median time to IST discontinuation of 349 (138-920) days. The cumulative incidence (CI) of cGHVD resolution was 41%, 69 and 77% at 1-, 2- and 3-years, respectively. No systemic corticosteroids were used in 27 patients, and 67% received ≤ 10 mg/kg cumulative exposure. Overall survival (OS) at 1-, 2- and 3-years following cGVHD diagnosis was 87, 79 and 77% respectively; corresponding rates of non-relapse mortality (NRM) were 10%, 16 and 19%. The probability of being alive and free of cGVHD at 1-, 2-, and 3-years was 36, 55, and 57% respectively. This study demonstrates the feasibility and efficacy of rituximab-based first-line cGVHD treatment. This approach demonstrates significant activity and avoids long courses of corticosteroids in most patients.

Prospective evaluation of sequential treatment of sclerotic chronic graft versus host disease with rituximab and nilotinib

Sclerotic chronic graft vs. host disease (cGVHD) still has a large impact on morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). We performed the first prospective study to test whether sequential therapy of the anti-CD20 antibody rituximab followed by 6 months treatment with tyrosine kinase inhibitor nilotinib is a favorable treatment strategy for patients with sclerotic cGVHD. Twenty-nine patients were included, 24 were available for analysis. We observed objective responses in 71% of patients (two patients CR, 15 patients PR). Moreover, two out of five patients suffering from severe ulcerations showed complete resolution of ulcers. Observed responses lasted until the end of study follow-up. The majority of responding patients could reduce daily corticosteroid dose with more than 50%. Furthermore, CD5+ B-cells are significantly lower (p = 0.007) in responding patients at baseline, proposing a new biomarker predictive for response. In conclusion, sequential treatment of rituximab followed by nilotinib associates with a very high response rate in this difficult to treat patient population. CD5+ B-cells could assist in guiding treatment choices and might be a first step toward more personalized cGVHD treatment. This trial was registered at the Dutch clinical trial registry as NTR1222.

Steroid Refractory Chronic Graft-Versus-Host Disease: Cost-Effectiveness Analysis

Given the increasing incidence of chronic graft-versus-host disease (cGVHD) and its rapidly escalating costs due to many lines of drug treatments, we aimed to perform a meta-analysis to assess the comparative effectiveness of various treatment options. Using these results, we then conducted a cost-effectiveness analysis for the frequently utilized agents in steroid-refractory cGVHD. We searched for studies examining tacrolimus, sirolimus, rituximab, ruxolitinib, hydroxychloroquine, imatinib, bortezomib, ibrutinib, extracorporeal photopheresis, pomalidomide, and methotrexate. Studies with a median follow-up period shorter than 6 months and enrolling fewer than 5 patients were excluded. Meta-analysis for overall and organ system-specific GVHD response (overall response [ORR], complete response [CR], and partial response [PR]) was conducted for each intervention. Cost per CR and cost per CR + PR were calculated as the quotient of the 6-month direct treatment cost by CR and CR + PR. Forty-one studies involving 1047 patients were included. CR rates ranged from 7% to 30% with rituximab and methotrexate, respectively, and ORR ranged from 30% to 85% with tacrolimus and ruxolitinib, respectively. Cost per CR ranged from US$1,187,657 with ruxolitinib to US$680 with methotrexate. Cost per ORR ranged from US$453 for methotrexate to US$242,236 for ibrutinib. The most cost-effective strategy was methotrexate for all of the organ systems. Pomalidomide was found to be the least cost-effective treatment for eye, gastrointestinal, fascia/joint, skin, and oral GVHD, and imatinib was found to be the least cost-effective treatment for liver and extracorporeal photopheresis for lung GVHD. We observed huge cost-effectiveness differences among available agents. Attention to economic issues when treating cGVHD is important to recommend how treatments should be sequenced, knowing that many patients will cycle through available agents.

The Role of B Cell Targeting in Chronic Graft-Versus-Host Disease

Chronic graft-versus-host disease (cGVHD) is a leading cause of late morbidity and mortality following allogeneic stem cell transplantation. Current therapies, including corticosteroids and calcineurin inhibitors, are only effective in roughly 50% of cases; therefore, new treatment strategies are under investigation. What was previously felt to be a T cell disease has more recently been shown to involve activation of both T and B cells, as well as a number of cytokines. With a better understanding of its pathophysiology have come more expansive preclinical and clinical trials, many focused on B cell signaling. This report briefly reviews our current understanding of cGVHD pathophysiology and reviews clinical and preclinical trials with B cell-targeted agents.

Acute and chronic Graft-versus-host disease after hematopoietic stem cell transplantation

graft-versus-host disease (GVHD) is one of the main complications of hematopoietic stem cell transplantation, affecting about 50% to 80% of the patients. Acute GVHD and its clinical manifestations are discussed in this article, as well as the new NIH criteria for the diagnosis and classification of chronic GVHD. Therapy for both chronic and acute GVHD is an important field of discussion, as there is no proven superiority for the majority of therapies used after primary treatment has failed. Hence, this review is meant to be a useful consultation tool for hematologists dealing with this complex transplantation procedure complication.

Impact of Donor Epstein-Barr Virus Serostatus on the Incidence of Graft-Versus-Host Disease in Patients With Acute Leukemia After Hematopoietic Stem-Cell Transplantation: A Study From the Acute Leukemia and Infectious Diseases Working Parties of the European Society for Blood and Marrow Transplantation

PURPOSE

We investigated the effect of Epstein-Barr virus (EBV) serostatus on the overall outcome of allogeneic hematopoietic stem-cell transplantation (allo-HSCT).

PATIENTS AND METHODS

The study included 11,364 patients who underwent allogeneic peripheral-blood or bone marrow transplantation for acute leukemia between 1997 and 2012. We analyzed the impact of donor and recipient EBV serologic status on overall survival, relapse-free survival, relapse incidence, nonrelapse mortality, and incidence of graft-versus-host disease (GVHD) after allo-HSCT.

RESULTS

Patients receiving grafts from EBV-seropositive donors had the same overall survival as patients who received grafts from EBV-seronegative donors (hazard ratio [HR], 1.05; 95% CI, 0.97 to 1.12; P = .23). Seropositive donors also had no influence on relapse-free survival (HR, 1.04; 95% CI, 0.97 to 1.11; P = 0.31), relapse incidence (HR, 1.03; 95% CI, 0.94 to 1.12; P = .58), and nonrelapse mortality (HR, 1.05; 95% CI, 0.94 to 1.17; P = .37). However, in univariate analysis, recipients receiving grafts from seropositive donors had a higher risk of chronic GVHD than those with seronegative donors (40.8% v 31.0%, respectively; P < .001; HR, 1.42; 95% CI, 1.30 to 1.56). When adjusting for confounders, higher risk was identified for both acute and chronic GVHD. In seronegative patients with seropositive donors, the HR for chronic GVHD was 1.30 (95% CI, 1.06 to 1.59; P = .039). In seropositive patients with seropositive donors, the HR was 1.24 (95% CI, 1.07 to 1.45; P = .016) for acute GVHD and 1.43 (95% CI, 1.23 to 1.67; P < .001) for chronic GVHD. Seropositive patients with seronegative donors did not have an increased risk of GVHD.

CONCLUSION

Our data suggest that donor EBV status significantly influences development of acute and chronic GVHD after allo-HSCT.

Risk of graft-versus-host disease with rituximab-containing conditioning regimens in allogeneic hematopoietic stem cell transplant

Graft-versus-host disease represents a major cause of morbidity and mortality in allogeneic hematopoietic stem cell transplant patients. There is growing evidence that B lymphocytes may play a role in the pathogenesis of acute graft-versus-host disease. The purpose of this retrospective cohort study was to evaluate the efficacy of rituximab-containing conditioning regimens in decreasing graft-versus-host disease in allogeneic hematopoietic stem cell transplant patients who received standardized tacrolimus-based graft-versus-host disease prophylaxis regimens. Patients were divided into two cohorts, based on the presence (RTX, n = 54) or absence (No-RTX, n = 105) of rituximab in the conditioning regimen and were matched 1:2 for major graft-versus-host disease risk factors. The incidence of grade II-IV acute graft-versus-host disease was not different between the two groups (37% vs. 26%, p = 0.147). When restricting the analysis to recipients of peripheral blood hematopoietic stem cell transplants, the RTX group had a higher incidence of grade II-IV acute graft-versus-host disease, relapse, or death prior to day 100 (55% vs. 36%, p = 0.037). The median time to the onset of acute graft-versus-host disease was no different between the RTX and No-RTX groups (67 vs. 74 days, respectively, p = 0.141). Inhibition of antigen presentation by B cells with rituximab-based conditioning regimens does not appear to reduce the incidence of acute graft-versus-host disease in allogeneic hematopoietic stem cell transplant recipients.

A Randomized Phase II Crossover Study of Imatinib or Rituximab for Cutaneous Sclerosis after Hematopoietic Cell Transplantation

PURPOSE

Cutaneous sclerosis occurs in 20% of patients with chronic graft-versus-host disease (GVHD) and can compromise mobility and quality of life.

EXPERIMENTAL DESIGN

We conducted a prospective, multicenter, randomized, two-arm phase II crossover trial of imatinib (200 mg daily) or rituximab (375 mg/m(2) i.v. weekly × 4 doses, repeatable after 3 months) for treatment of cutaneous sclerosis diagnosed within 18 months (NCT01309997). The primary endpoint was significant clinical response (SCR) at 6 months, defined as quantitative improvement in skin sclerosis or joint range of motion. Treatment success was defined as SCR at 6 months without crossover, recurrent malignancy or death. Secondary endpoints included changes of B-cell profiles in blood (BAFF levels and cellular subsets), patient-reported outcomes, and histopathology between responders and nonresponders with each therapy.

RESULTS

SCR was observed in 9 of 35 [26%; 95% confidence interval (CI); 13%-43%] participants randomized to imatinib and 10 of 37 (27%; 95% CI, 14%-44%) randomized to rituximab. Six (17%; 95% CI, 7%-34%) patients in the imatinib arm and 5 (14%; 95% CI, 5%-29%) in the rituximab arm had treatment success. Higher percentages of activated B cells (CD27(+)) were seen at enrollment in rituximab-treated patients who had treatment success (P = 0.01), but not in imatinib-treated patients.

CONCLUSIONS

These results support the need for more effective therapies for cutaneous sclerosis and suggest that activated B cells define a subgroup of patients with cutaneous sclerosis who are more likely to respond to rituximab.

Pharmacokinetics and pharmacodynamics of ASKP1240, a fully human anti-CD40 antibody, in normal and renal transplanted Cynomolgus monkeys

BACKGROUND

The purpose of this study was to evaluate the serum concentration of ASKP1240 (pharmacokinetics [PK]) and the CD40 occupancy of ASKP1240 (pharmacodynamics [PD]) in normal and renal transplanted Cynomolgus monkeys to clarify the PK/PD relationship.

METHODS

In a 70-day study, two ASKP1240 doses (2 and 5 mg/kg) were evaluated in normal and transplanted monkeys. Full doses were administered during the induction phase, and half doses were administered during the maintenance phase. The PK and PD were assessed using ELISA and FACS assays.

RESULTS

The serum concentration and receptor occupancy of ASKP1240 reached their maximum levels rapidly after the first dose and remained at an almost saturated rate during the induction phase. They then decreased gradually during the maintenance phase in all of the groups. The serum concentration and duration of full receptor occupancy were dose dependent in the normal and transplanted monkeys. On day 70 after therapy with 5 mg/kg ASKP1240, the transplanted monkeys presented a significantly lower occupancy of the CD40 receptors compared with the normal animals (5.5%±14.1% vs. 72.8%±3.4%). The serum concentration of ASKP1240 was also strongly correlated with the occupancy of the ASKP1240 receptors.

CONCLUSION

This study showed strong positive PK/PD relationships in renal transplanted and normal monkeys. The results may thus serve as a guide for optimal dosage and timing of ASKP1240 therapy in clinical trials and will propel the translation of ASKP1240 therapeutics from the bench to preclinical and clinical trials.

B-cell-mediated strategies to fight chronic allograft rejection

Solid organs have been transplanted for decades. Since the improvement in graft selection and in medical and surgical procedures, the likelihood of graft function after 1 year is now close to 90%. Nonetheless even well-matched recipients continue to need medications for the rest of their lives hence adverse side effects and enhanced morbidity. Understanding Immune rejection mechanisms, is of increasing importance since the greater use of living-unrelated donors and genetically unmatched individuals. Chronic rejection is devoted to T-cells, however the role of B-cells in rejection has been appreciated recently by the observation that B-cell depletion improve graft survival. By contrast however, B-cells can be beneficial to the grafted tissue. This protective effect is secondary to either the secretion of protective antibodies or the induction of B-cells that restrain excessive inflammatory responses, chiefly by local provision of IL-10, or inhibit effector T-cells by direct cellular interactions. As a proof of concept B-cell-mediated infectious transplantation tolerance could be achieved in animal models, and evidence emerged that the presence of such B-cells in transplanted patients correlate with a favorable outcome. Among these populations, regulatory B-cells constitute a recently described population. These cells may develop as a feedback mechanism to prevent uncontrolled reactivity to antigens and inflammatory stimuli. The difficult task for the clinician, is to quantify the respective ratios and functions of “tolerant” vs. effector B-cells within a transplanted organ, at a given time point in order to modulate B-cell-directed therapy. Several receptors at the B-cell membrane as well as signaling molecules, can now be targeted for this purpose. Understanding the temporal expansion of regulatory B-cells in grafted patients and the stimuli that activate them will help in the future to implement specific strategies aimed at fighting chronic allograft rejection.

Anti-CD20 monoclonal antibodies: beyond B-cells

Anti-CD20 monoclonal antibodies (MoAbs), employed in treating CD20⁺ lymphomas and autoimmune diseases, appear to have broader functions than just eradicating malignant B-cells and decreasing autoantibody production. Rituximab-induced T-cell inactivation, reported both in-vitro and in-vivo, may contribute to the increased risk of T-cell-dependent infections, observed in patients receiving this therapy. T-cell polarization into a suppressive phenotype, often observed in patients receiving rituximab for autoimmune disorders, was reported to be associated with prolonged remissions. Elimination of B-cells serving as antigen-presenting cells, thereby causing impaired T-cell activation, could play a significant role in induction of these changes. Direct binding of rituximab to a CD20dim T-cell population, inducing its depletion, may contribute to the decreased T-cell activation following rituximab therapy. Further investigation of the complex network through which rituximab and new anti-CD20 MoAbs act, would advance the employment of these agents in different clinical settings.

Rituximab prophylaxis prevents corticosteroid-requiring chronic GVHD after allogeneic peripheral blood stem cell transplantation: results of a phase 2 trial

B cells are implicated in the pathophysiology of chronic graft-vs-host disease (GVHD), and phase 2 trials suggest that B cell depletion can treat established chronic GVHD. We hypothesized that posttransplantation B cell depletion could prevent the occurrence of chronic GVHD. We performed a 65-patient phase 2 trial of rituximab (375 mg/m(2) IV), administered at 3, 6, 9, and 12 months after transplantation. Rituximab administration was safe without severe infusional adverse events. The cumulative incidences of chronic GVHD and systemic corticosteroid-requiring chronic GVHD at 2 years from transplantation were 48% and 31%, respectively, both lower than the corresponding rates in a concurrent control cohort (60%, P = .1, and 48.5%, P = .015). There was no difference in relapse incidence, but treatment-related mortality at 4 years from transplantation was significantly lower in treated subjects when compared with controls (5% vs 19%, P = .02), and overall survival was superior at 4 years (71% vs 56%, P = .05). At 2 years from transplantation, the B-cell activating factor/B-cell ratio was significantly higher in subjects who developed chronic GVHD in comparison with those without chronic GVHD (P = .039). Rituximab can prevent systemic corticosteroid-requiring chronic GVHD after peripheral blood stem cell transplantation and should be tested in a prospective randomized trial.

Recent progress in managing graft-versus-host disease and viral infections following allogeneic stem cell transplantation

Despite recent reductions in transplant-related mortality, post-transplant complications such as graft-versus-host disease (GvHD) remain major obstacles to the successful application of allogeneic hematopoietic transplantation. Steroid-refractory GvHD has a poor outcome. Although there are a variety of new approaches to the treatment of refractory GvHD, many have limited evidence of efficacy. Other approaches appear to be unacceptably toxic. It would be preferable to improve GvHD prophylaxis. There is good evidence that rates of GvHD can be reduced without unacceptable reduction of the graft-versus-leukemia effect or compromising overall survival. However, prophylactic measures aimed at reducing T-cell numbers or functions are associated with high rates of reactivation of latent viruses. New technologies that allow rapid generation of virus-specific T-cells show promise to reduce the frequency and severity of such reactivations and have the potential to revolutionize the approach to post-transplant infectious complications.

Histological assessment of the sclerotic graft-versus-host response in the humanized RAG2-/-γc-/- mouse model

Graft-versus-host disease (GVHD) remains a frequently occurring and difficult-to-treat complication in human allogeneic stem cell transplantation. Murine transplantation models are often used to study and understand the complex pathogenesis of GVHD and to explore new treatment strategies. Although GVHD kinetics may differ in murine and human models, adequate models are essential for identification of the crucial factors responsible for the major pathology in GVHD. We present a detailed description of the specific histological features of a graft-versus-host-induced fibrotic response in xenogeneic RAG2(-/-)γc(-/-) mice after total body irradiation and injection with human peripheral blood mononuclear cells. We describe the full morphological features of this reaction, including a detailed analysis of the specific tissue infiltration patterns of the human peripheral blood mononuclear cells. Our data show the development of fibrosis, predominantly near blood vessels, and reveal different cell populations and specific cell migration patterns in the affected organs. The combination of immunohistochemical cell characterization and mRNA expression analysis of both human (donor)- and murine (host)-derived cytokines reveals an interaction between host tissues and donor-derived cells in an entangled cytokine profile, in which both donor- and host-derived cytokines contribute to the formation of fibrosis.

Graft-versus-host disease: part II. Management of cutaneous graft-versus-host disease

Dermatologists are ideally suited to manage the various cutaneous sequelae of graft-versus-host disease (GVHD) outlined in part I of this review. However, the complexity of the patient with GVHD, including comorbidities, potential drug interactions related to polypharmacy, and the lack of evidence-based treatment guidelines, are significant challenges to optimizing patient care. In this section, we will provide an outline for the role of the dermatologist in a multispecialty approach to caring for patients with GVHD.

The use of monoclonal antibodies in immune-mediated hematologic disorders

In this article, the evidence on the clinical use of monoclonal antibodies in the treatment of immune-mediated hematologic disorders is described. Insights into pathogenic mechanisms have revealed a major role of both B and T cells. Controlled trials have shown conflicting results, necessitating further research regarding pathogenesis, mechanism of action, and resistance. Although the use of more potent and specific monoclonal antibody therapy, mainly targeting costimulation signals, may improve response rates and long-term outcome, its use should be carefully balanced against potential side effects.

Effectiveness of subcutaneous low-dose alemtuzumab and rituximab combination therapy for steroid-resistant chronic graft-versus-host disease

BACKGROUND

Chronic graft-versus-host disease is a common late complication of allogeneic hematopoietic stem cell transplantation. Corticosteroids are the standard initial treatment. Second-line treatment has not been well defined. We evaluated the effectiveness and safety of low doses of alemtuzumab plus low doses of rituximab in the treatment of steroid-refractory chronic graft-versus-host disease.

DESIGN AND METHODS

Ten men and 5 women were prospectively included in the study. All patients received one cycle of subcutaneous alemtuzumab 10 mg/day/3 days and intravenous rituximab 100 mg on Days +4, +11, +18 and +25. The therapeutic response was measured on Days +30, +90 and +365 of the protocol.

RESULTS

Median age was 41 years. The main site involved was the oral mucosa (86.7%) followed by the eyes (66.7%), liver (60%), skin (53%), lungs (13.3%) and intestinal tract (6.7%). The overall response was 100% at Day +30 evaluation: 10 patients (67%) had partial remission, 5 (33%) had complete remission. At Day +90 evaluation, 7 (50%) patients had partial remission, 4 (28%) had complete remission; 3 (21%) had relapsed chronic graft-versus-host disease and one patient did not reach the evaluation time point. So far, 5 patients have reached the Day +365 follow-up evaluation; 2 (40%) had partial remission, 2 had complete remission and one experienced chronic graft-versus-host disease progression. Adverse effects were mainly infections in 67% of patients; these were all quickly solved, except for one patient who died from pneumonia.

CONCLUSIONS

This combination therapy appears to be an efficacious and safe treatment for steroid-refractory chronic graft-versus-host disease. Longer follow up to determine the durability of response and survival is required (ClinicalTrials.gov: NCT01042509).

Donor B-cell alloantibody deposition and germinal center formation are required for the development of murine chronic GVHD and bronchiolitis obliterans

Chronic GVHD (cGVHD) poses a significant risk for HSCT patients. Preclinical development of new therapeutic modalities has been hindered by models with pathologic findings that may not simulate the development of human cGVHD. Previously, we have demonstrated that cGVHD induced by allogeneic HSCT after a conditioning regimen of cyclophosphamide and total-body radiation results in pulmonary dysfunction and airway obliteration, which leads to bronchiolitis obliterans (BO), which is pathognomonic for cGVHD of the lung. We now report cGVHD manifestations in a wide spectrum of target organs, including those with mucosal surfaces. Fibrosis was demonstrated in the lung and liver and was associated with CD4(+) T cells and B220(+) B-cell infiltration and alloantibody deposition. Donor bone marrow obtained from mice incapable of secreting IgG alloantibody resulted in less BO and cGVHD. Robust germinal center reactions were present at the time of cGVHD disease initiation. Blockade of germinal center formation with a lymphotoxin-receptor-immunoglobulin fusion protein suppressed cGVHD and BO. We conclude that cGVHD is caused in part by alloantibody secretion, which is associated with fibrosis and cGVHD manifestations including BO, and that treatment with a lymphotoxin-β receptor-immunoglobulin fusion protein could be beneficial for cGVHD prevention and therapy.

Tirosin kinase inhibitors in chronic graft versus host disease: from bench to bedside

Chronic Graft Versus Host Disease (cGVHD) is a major complication of allogeneic stem-cell transplantation (SCT). In many inflammatory fibrotic diseases, such as Systemic Scleroderma (SSc) and cGVHD with fibrotic features, an abnormal activation of transforming growth factor (TGFβ) and platelet-derived growth factor receptor (PDGF-R) pathways have been observed. Tyrosin Kinase Inhibitors (TKIs), which are currently used for treatment of patients with Chronic Myeloid Leukemia (CML), share potent antifibrotic and antiinflammatory properties, being powerful dual inhibitors of both PDGF-R and TGFβ pathways. Moreover accumulating in vitro data confirm that TKIs, interacting with the TCR and other signalling molecules, carry potent immunomodulatory effects, being involved in both T-cell and B-cell response. Translation to the clinical setting revealed that treatment with Imatinib can achieve encouraging responses in patients with autoimmune diseases and steroid-refractory cGVHD, showing a favourable toxicity profile. While the exact mechanisms leading to such efficacy are still under investigation, use of TKIs in the context of clinical trials should be promoted, aiming to evaluate the biological changes induced in vivo by TKIs and to assess the long term outcome of these patients. Second-generation TKIs, with more favourable toxicity profile are under evaluation in the same setting.

B cell homeostasis and the development of chronic graft-versus-host disease: implications for B cell-depleting therapy

Chronic graft-versus-host disease (GVHD) is a serious complication that develops frequently in survivors of allogeneic stem cell transplant. Since elucidation of the role of B cells in the pathogenesis of chronic GVHD, B cell-depleting therapy with rituximab has been associated with beneficial effects in clinical and laboratory studies in patients with chronic GVHD. Although the mechanism underlying the contribution of B cells to the development of chronic GVHD is poorly understood, recent studies have proposed that B cell reconstitution after allogeneic stem cell transplant is involved in the development of chronic GVHD. Inadequate reconstitution of naive B cells and the persistence of high levels of B cell-activating factor have been found in patients with chronic GVHD, and these changes might be associated with the expansion of activated CD27-positive B cells that produce autoantibody in chronic GVHD. In the light of this altered B cell homeostasis in chronic GVHD, the role of rituximab in controlling the clinical manifestations of chronic GVHD has been studied. In this review, we address the role of B cells in the pathogenesis of chronic GVHD and the response to B cell-depleting therapy based on B cell homeostasis.

Treatment of graft-versus-host disease with monoclonal antibodies and related fusion proteins

Allogeneic hematopoietic stem cell transplantation has evolved from an experimental treatment approach to a widely used, curative therapy to treat malignant and nonmalignant diseases of the hematopoietic system. Despite advances in donor selection, conditioning regimens and supportive care, acute and chronic graft-versus-host disease (GvHD) remain a major cause of morbidity and mortality. Steroids are the standard first-line treatment and are able to control GvHD in approximately 50% of patients. Those who fail on steroids have a poor long-term prognosis. Therefore, a large number of drugs and procedures have been evaluated as second-line therapy. Monoclonal antibodies have increasingly been used to treat malignancy and autoimmune disease during the last 20 years. Their unique ability to target specific antigens theoretically enables them to directly interfere with cellular mechanisms that are involved in GvHD pathology. For this reason, monoclonal antibodies have been studied extensively as a second-line treatment for acute and chronic GvHD. The purpose of this article is to collect published data on clinical trials from the current literature and to give an overview on efficacy and toxicity of monoclonal antibody treatment for GvHD.

Rituximab for prevention and treatment of graft-versus-host disease

Growing understanding of the important role of B lymphocytes in alloreactivity has paved the way for evaluating anti-B cell therapy with rituximab in patients undergoing allogeneic hematopoietic cell transplantation. Data suggesting a beneficial reduction in incidence and severity of acute graft-versus-host disease (GVHD) are limited to non-randomized studies from single institutions using higher than conventional doses of rituximab. Additionally, rituximab is used as an effective treatment of corticosteroid-refractory chronic GVHD with good responses, particularly in cases of dermatologic and mucosal involvement. Post-transplant administration of rituximab appears to reduce the rate of chronic GVHD in preliminary studies.

The immunological phenotype of rituximab-sensitive chronic graft-versus-host disease: a phase II study

Chronic graft-versus-host disease is the major long-term complication after allogeneic stem cell transplantation with a suboptimal response rate to current treatments. Therefore, clinical efficacy and changes in lymphocyte subsets before and after rituximab treatment were evaluated in a prospective phase II study in patients with steroid-refractory chronic graft-versus-host disease. Overall response rate was 61%. Only responding patients were found to have increased B-cell numbers prior to treatment. B cells had a naïve-antigen-presenting phenotype and were mainly CD5 negative or had a low CD5 expression. Normal B-cell homeostasis was reestablished in responding patients one year after ritxumab treatment and associated with a significant decline in skin-infiltrating CD8(+) T cells, suggesting that host B cells play a role in maintaining pathological CD8(+) T-cell responses. Imbalances in B-cell homeostasis could be used to identify patients a priori with a higher chance of response to rituximab treatment (Eudra-CT 2008-004125-42).

Current and future approaches for control of graft-versus-host disease

Graft-versus-host disease (GVHD), both acute and chronic, remains one of the major barriers to improving outcomes after allogeneic stem cell transplantation. The pathophysiology of GVHD is complex and incompletely understood. GVHD is believed to arise from the interaction of: tissue damage and proinflammatory cytokines causing activation of antigen-presenting cells (APCs, donor T-cell activation by APCs and cytokines and host tissue injury by effector T lymphocytes and proinflammatory cytokines. There is also a role for additional lymphocyte subtypes (naive and memory T cells, regulatory T cells, natural killer T cells and B cells) in GVHD pathogenesis. Strategies to improve donor-recipient HLA match, and to minimize conditioning toxicity, cytokine release and APC and effector T-lymphocyte activation, will likely improve prophylaxis of acute (and possibly chronic) GVHD. Therapy of established acute and chronic GVHD is still heavily dependent on corticosteroids, despite their limited efficacy and considerable toxicity. Novel agents (and/or combinations of agents) comprising pharmacologic, biologic and cellular therapies targeting specific steps or subsets involved in immune activation will likely comprise future advances in GVHD control. This article reviews the current state of knowledge regarding the prevention and treatment of acute and chronic GVHD. Novel approaches currently undergoing evaluation are also highlighted.

The use of monoclonal antibodies for the treatment of graft-versus-host disease following allogeneic stem cell transplantation

INTRODUCTION

Graft-versus-host disease (GVHD) remains the leading cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Steroids along with calcineurin inhibitors remain the standard initial therapy, however, less than half of the patients completely respond and there is no uniformly accepted therapy for patients with steroid-resistant GVHD.

AREAS COVERED

This paper reviews the current role and ongoing development of mAbs in the treatment of GVHD. Various mAbs to cell surface antigens on GVHD effector cells have been investigated for the treatment of acute GVHD: these include anti-TNF-α antibodies, IL-2 receptor antagonists, anti-CD3 and anti-CD52 mAbs, while anti-CD20 mAb has been extensively investigated in the setting of chronic GVHD. Overall, response rates have been reported to be greater than 60%, although it should be emphasized that the long-term survival still remains suboptimal, mainly due to the detrimental side effects of infectious complications, progressive GVHD and relapse of underlying malignancy.

EXPERT OPINION

Future challenges will include more appropriate definition of these agents in the therapeutic scenario of GVHD. Combinations of mAbs or mAb combined with newer immunosuppressive drugs might potentially achieve greater success, especially if used early in the disease process.

Anti-CD20 monoclonal antibodies and their use in adult autoimmune hematological disorders

Autoimmune hematological disorders encompass a broad group of hematological conditions characterized by the loss of self-tolerance to a variety of antigens. Despite good response to first-line therapy in the majority of patients, relapses are common, necessitating new and safe therapeutic options. The anti-CD20 monoclonal antibody rituximab has led to substantial improvement in the treatment of malignant and immune-mediated disorders involving B cells. Although experience with rituximab in immune-mediated hematological disorders is rarely supported by randomized trials, there is now substantial experience with rituximab suggesting that anti-CD20 therapy is an effective and well-tolerated alternative to immunosuppressive therapy in these disorders. However, caution is needed based on recent reports describing-sometimes severe-rituximab-related complications.

B cells--masters of the immunoverse

The immune system involves the complex interplay between many different cell types. Over the last decade, T cells, dendritic cells (DC) and macrophages have all been implicated as the key regulator cells of the immunological response, linking innate and adaptive immunity. The forgotten cell in this discourse has been the B-cell. Long considered as simple antibody production units dictated to by T-cells, recent years have begun to shift this assumption. The discovery that numerous B-cell subsets exist, with specific regulatory functions capable of modulating T-cell and chronic inflammatory responses has revealed a hitherto unappreciated role of B-cells. In particular, these ideas have been developed in light of the surprisingly successful responses delivered in autoimmune settings following depletion of B-cells with the anti-CD20 antibody rituximab. Here we summarise the history of the humble B-cell and discuss some of the key recent findings that lead us to propose it as an important regulator of ongoing immune responses and as such, one of the masters of the immunoverse.

Innovative uses of rituximab in dermatology

Since its approval in 1997 by the US Food and Drug Administration, rituximab has been approved for use in certain B-cell lymphomas and treatment-resistant rheumatoid arthritis. Over the past 10 years, many published reports have suggested rituximab's efficacy in several inflammatory conditions in dermatology. This article includes a review of the mechanism of action, dosing, side-effect profile, and the current literature for various off-label uses of this CD20+ B-cell antagonist, rituximab.

The role of rituximab in autologous and allogeneic hematopoietic stem cell transplantation for non-Hodgkin's lymphoma

The addition of rituximab to chemotherapy has substantially changed the treatment strategies for patients with B-cell lymphomas. Rituximab, combined with standard chemotherapy regimens, shows consistently improved results compared with chemotherapy alone and has been extensively employed in both newly diagnosed and relapsed patients with B-cell lymphoma. Because of its low toxicity profile and its potent antilymphoma activity mediated through direct apoptotic and indirect effector mechanisms, rituximab also has been actively incorporated into stem cell transplantation (SCT) protocols to attain a state of minimal disease, provide a safe and effective method for in vivo purging prior to autologous SCT, and promote graft-versus-lymphoma effects in allogeneic SCT. This review compiles the still immature but rapidly growing data on this combined modality.

Weekly rituximab followed by monthly rituximab treatment for steroid-refractory chronic graft-versus-host disease: results from a prospective, multicenter, phase II study

BACKGROUND

Since it was suggested that B cells play a role in the pathogenesis of chronic graft-versus-host disease, rituximab, an anti-CD20 monoclonal antibody targeting B cells, has been shown to be effective in steroid-refractory, chronic graft-versus-host disease. However, most of the data were from small numbers of patients or retrospective analyses. We, therefore, conducted a multicenter phase II study to confirm the efficacy of this treatment strategy that targets B cells.

DESIGN AND METHODS

We diagnosed and evaluated chronic graft-versus-host disease according to the National Institute of Health criteria for clinical trials on this condition. The treatment consisted of weekly intravenous infusions of rituximab for 4 weeks followed by monthly rituximab for 4 months. We evaluated the patients' responses and monitored their disease activity until their final visit, which was on day 365. We also assessed the patients' subsequent quality of life and serum levels of B-cell-activating factor of the tumor necrosis factor family.

RESULTS

Among 37 patients enrolled (median age, 29 years; range 8-57 years), 32 patients responded to rituximab with 8 complete and 24 partial responses. Twenty-one patients maintained their response for 1 year, so their steroid treatment was discontinued or its dose reduced (21/37, or 56.8%), and their scores representing quality of life were improved although these changes were not statistically significant. The responses were better for clinical manifestations of the skin, oral cavity and musculoskeletal system (response rate, 71.4-100%) than for other organs. However, infectious complications and primary disease relapse accounted for the majority of treatment failure. The pre-treatment serum level of B cell-activating factor of the tumor necrosis factor family was not associated with better treatment outcome (P=0.147).

CONCLUSIONS

Rituximab could improve clinical responses and quality of life of patients with steroid-refractory chronic graft-versus-host disease, although such patients may need active prophylaxis against infection.

Consensus Conference on Clinical Practice in Chronic GVHD: Second-Line Treatment of Chronic Graft-versus-Host Disease

Steroid refractory chronic graft-versus-host disease (cGVHD) is associated with a significant morbidity and mortality. Although first-line treatment of cGVHD is based on controlled trials, second-line treatment is almost solely based on phase II trials or retrospective analyses. The consensus conference on clinical practice in cGVHD held in Regensburg aimed to achieve a consensus on the current evidence of treatment options as well as to provide guidelines for daily clinical practice. Treatment modalities are the use of steroids and calcineurin inhibitors as well as immunomodulating modalities (photopheresis, mTOR-inhibitors, thalidomide, hydroxychloroquine, vitamin A analogs, clofazimine), and cytostatic agents (mycophenolate mofetil, methotrexate, cyclophosphamide, pentostatin). Recent reports showed some efficacy of rituximab, alemtuzumab, and etanercept in selected patients. Moreover, tyrosine kinase inihibitors such as imatinib came into the field because of their ability to interfere with the platelet-derived growth factor (PDGF-R) pathway involved in fibrosis. An other treatment option is low-dose thoracoabdominal irradiation. Although different treatment options are available, the "trial-and-error system" remains the only way to identify the drug effective in the individual patient, and valid biomarkers are eagerly needed to identify the likelihood of response to a drug in advance. Moreover, the sparse evidence for most treatment entities indicates the urgent need for systematic evaluation of second-line treatment options in cGVHD.

Frequent expression of C4d in hepatic graft-versus-host disease: potential clue for diagnosis and distinguishing acute and chronic form

BACKGROUND

Graft-versus-host disease (GVHD), a common complication of hematopoietic stem cell transplant, is generally regarded to develop through cell-mediated immune response following activation of helper T cells. Since production of antibodies is also mediated by helper T cells, the role of humoral immunity in GVHD is questioned and has not yet been explored in clinical practice. We conducted a pilot study to evaluate the role of antibody production in hepatic H-GVHD and whether it can distinguish acute and chronic forms.

RESULTS

C4d expression was increased in portal vessels and hepatic sinusoids of patients with histological proven evidence of GVHD 11/16 (P=0.007). Patients classified as chronic GVHD were statistically more likely to have C4d expression in the portal vasculature and liver sinusoids (P=0.011).

CONCLUSION

Humoral activation seems to play a role in pathophysiology of hepatic, especially chronic GVHD.