Treatment of steroid-resistant acute graft-versus-host disease with rabbit antithymocyte globulin

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.

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.

Inpatient Management of Mucocutaneous GVHD

Purpose of Review

Graft-versus-host disease (GVHD) is an immune mediated disorder affecting 30 - 70% of patients after allogeneic hematopoietic stem cell transplantation (alloHSCT), and is a major cause of morbidity and non-relapse mortality (NRM) [1]. Dermatologists play a critical role in acute and chronic GVHD, as skin involvement is common and often the earliest involved site of disease [2].

Recent Findings

GVHD shares clinical and histopathological features with a variety of other skin diseases, requiring thorough consideration of differential diagnoses in hematopoietic stem cell transplantation (HSCT) recipients with lesions suggestive of cutaneous GVHD. Treatment considerations for GVHD are influenced by factors such as disease classification, overall grading, organ involvement, associated symptoms, and immunological anti-tumor effect. Several treatments are available and may be indicated as monotherapy or adjuvant therapy to allow faster withdrawal or tapering of immunosuppression. While corticosteroids are often first line therapy, oral ruxolitinib has been recently approved for treatment of steroid-refractory aGHVD, and oral ibrutinib has been approved for steroid-refractory cGHVD.

Summary

This article provides current clinical, diagnostic, and therapeutic considerations relevant to the hospitalist for both acute and chronic mucocutaneous GVHD. Optimal inpatient management of these diseases requires an interdisciplinary team.

How I treat steroid-refractory acute graft-versus-host disease

Steroid-resistant or steroid-refractory acute graft-versus-host disease (SR-aGVHD) poses one of the most vexing challenges faced by providers who care for patients after allogeneic hematopoietic cell transplantation. For the past 4 decades, research in the field has been driven by the premise that persistent graft-versus-host disease (GVHD) results from inadequate immunosuppression. Accordingly, most efforts to solve this problem have relied on retrospective or prospective studies testing agents that have direct or indirect immunosuppressive effects. Retrospective studies far outnumber prospective studies, and no controlled prospective trial has shown superior results for any agent over others. Truth be told, I do not know how to treat SR-aGVHD. Preclinical work during the past decade has provided fresh insights into the pathogenesis of acute GVHD, and translation of these insights toward development of more effective treatments for patients with SR-aGVHD has at last begun. Given the limited state of current knowledge, this "How I Treat" review highlights the overriding imperative to avoid harm in caring for patients with SR-aGVHD. Prospective trials that are widely available are urgently needed to advance the field.

Loss of nivolumab binding to T cell PD-1 predicts relapse of Hodgkin lymphoma

Nivolumab is effective in the treatment of classical Hodgkin lymphoma that relapsed after allogeneic hematopoietic stem cell transplantation (SCT) with the risk of graft-versus-host disease; however, the optimal time and dose of nivolumab administration remain to be investigated. Nivolumab binding to PD-1 masks flowcytometric detection of PD-1 by the anti-PD-1 monoclonal antibody EH12.1. Using this method, we monitored nivolumab binding on T cells after nivolumab treatment in a patient with classical Hodgkin lymphoma relapsed after allogeneic SCT. Nivolumab was effective while prolonged nivolumab binding was evident, but restoration of PD-1 staining predicted tumor relapse. Flowcytometric monitoring of nivolumab binding on T cells could be a promising biomarker for predicting tumor relapse and determining the timing of nivolumab administration.

The Role of Co-stimulatory/Co-inhibitory Signals in Graft-vs.-Host Disease

Allogeneic hematopoietic cell transplantation (allo-HCT) is an effective immunotherapeutic approach for various hematologic and immunologic ailments. Despite the beneficial impact of allo-HCT, its adverse effects cause severe health concerns. After transplantation, recognition of host cells as foreign entities by donor T cells induces graft-vs.-host disease (GVHD). Activation, proliferation and trafficking of donor T cells to target organs and tissues are critical steps in the pathogenesis of GVHD. T cell activation is a synergistic process of T cell receptor (TCR) recognition of major histocompatibility complex (MHC)-anchored antigen and co-stimulatory/co-inhibitory signaling in the presence of cytokines. Most of the currently used therapeutic regimens for GVHD are based on inhibiting the allogeneic T cell response or T-cell depletion (TCD). However, the immunosuppressive drugs and TCD hamper the therapeutic potential of allo-HCT, resulting in attenuated graft-vs.-leukemia (GVL) effect as well as increased vulnerability to infection. In view of the drawback of overbroad immunosuppression, co-stimulatory, and co-inhibitory molecules are plausible targets for selective modulation of T cell activation and function that can improve the effectiveness of allo-HCT. Therefore, this review collates existing knowledge of T cell co-stimulation and co-inhibition with current research that may have the potential to provide novel approaches to cure GVHD without sacrificing the beneficial effects of allo-HCT.

The Role of Anti-Thymocyte Globulin or Alemtuzumab-Based Serotherapy in the Prophylaxis and Management of Graft-Versus-Host Disease

Allogeneic hematopoietic stem cell transplant is an established treatment modality for hematologic and non-hematologic diseases. However, it is associated with acute and long-term sequelae which can translate into mortality. Graft-versus-host disease (GVHD) remains a glaring obstacle, especially with the advent of reduced-intensity conditioning. Serotherapy capitalizes on antibodies which target T cells and other immune cells to mitigate this effect. This article focuses on the utility of two such agents: anti-thymocyte globulin (ATG) and alemtuzumab. ATG has demonstrated benefit in prophylaxis against GVHD, especially in the chronic presentation. However, there is limited impact of ATG on overall survival and it has little utility in the treatment context. There may be an initial improvement, particularly in skin manifestations, but no substantial benefit has been elicited. Alemtuzumab has shown benefit in both prophylaxis and treatment of GVHD, but at the consequence of a more profound immunosuppressive phase, mandating aggressive viral prophylaxis. There remains heterogeneity in the doses and regimens of the agents, with no standardized protocol in place. Furthermore, it seems that once steroid-refractory GVHD has been established, there is little that can be offered to offset the ultimately dismal outcome. Here we present a systematic overview of ATG- or alemtuzumab-based serotherapy in the prophylaxis and management of GVHD.

Treatment Options in Steroid-Refractory Acute Graft-Versus-Host Disease Following Hematopoietic Stem Cell Transplantation

Objective:

To evaluate the treatment options in steroid-refractory acute graft-versus-host disease (GVHD) following hematopoietic stem cell transplantation.

Data Sources:

Literature was obtained by searching MEDLINE (1966–May 2007) and EMBASE (1980–May 2007).

Study Selection and Data Extraction:

All pertinent clinical trials, retrospective studies, case reports, and compassionate use studies were identified and evaluated for safety and efficacy of the pharmacologic agents.

Data Synthesis:

Steroid-refractory acute GVHD is associated with high rates of morbidity and mortality. Although various pharmacologic agents have been studied in the treatment of steroid-refractory acute GVHD, no treatments have been established as a salvage therapy. Preliminary data on different pharmacologic agents have been identified and evaluated for their efficacy and tolerability in the treatment of steroid-refractory acute GVHD. The effects of the pharmacologic agents varied significantly among patients: severity of the disease, involvement of different organs, and the patient's age seem to be the major factors that affect an individual's response to drug therapy. In addition, the treatments are further challenged by the high incidence of potentially fatal opportunistic infections that occur during the therapy.

Conclusions:

Selection of pharmacologic agents for the treatment of steroid-refractory acute GVHD should be based on the target organs, adverse drug reactions, and economic factors. Further studies with larger sample sizes are warranted to better understand the roles of these agents in the treatment of steroid-refractory acute GVHD.

A phase 3 randomized trial comparing inolimomab vs usual care in steroid-resistant acute GVHD

Treatment of steroid-resistant acute graft-versus-host disease (GVHD) remains an unmet clinical need. Inolimomab, a monoclonal antibody to CD25, has shown encouraging results in phase 2 trials. This phase 3 randomized, open-label, multicenter trial compared inolimomab vs usual care in adult patients with steroid-refractory acute GVHD. Patients were randomly selected to receive treatment with inolimomab or usual care (the control group was treated with antithymocyte globulin [ATG]). The primary objective was to evaluate overall survival at 1 year without changing baseline allocated therapy. A total of 100 patients were randomly placed: 49 patients in the inolimomab arm and 51 patients in the ATG arm. The primary criteria were reached by 14 patients (28.5%) in the inolimomab and 11 patients (21.5%) in the ATG arms, with a hazard ratio of 0.874 (P = .28). With a minimum follow-up of 1 year, 26 (53%) and 31 (60%) patients died in the inolimomab and ATG arms, respectively. Adverse events were similar in the 2 arms, with fewer viral infections in the inolimomab arm compared with the ATG arm. The primary end point of this randomized phase 3 trial was not achieved. The lack of a statistically significant effect confirms the need for development of more effective treatments for acute GVHD. This trial is registered to https://www.clinicaltrialsregister.eu/ctr-search/search as EUDRACT 2007-005009-24.

Low-dose thymoglobulin as second-line treatment for steroid-resistant acute GvHD: an analysis of the JSHCT

A nationwide retrospective study for the clinical outcomes of 99 patients who had received thymoglobulin at a median total dose of 2.5 mg/kg (range, 0.5-18.5 mg/kg) as a second-line treatment for steroid-resistant acute GvHD was conducted. Of the 92 evaluable patients, improvement (complete or partial response) was observed in 55 patients (60%). Multivariate analysis demonstrated that male sex and grade III and IV acute GvHD were associated with a lower improvement rate, whereas thymoglobulin dose (<2.0, 2.0-3.9 and ⩾4.0 mg/kg) was NS. Factors associated with significantly higher nonrelapse mortality included higher patient age (⩾50 years), grade IV acute GvHD, no improvement of GvHD and higher dose of thymoglobulin (hazard ratio, 2.55; 95% confidence interval, 1.34-4.85; P=0.004 for 2.0-3.9 mg/kg group and 1.79; 0.91-3.55; P=0.093 for ⩾4.0 mg/kg group). Higher dose of thymoglobulin was associated with a higher incidence of bacterial infections, CMV antigenemia and any additional infection. Taken together, low-dose thymoglobulin at a median total dose of 2.5 mg/kg provides a comparable response rate to standard-dose thymoglobulin reported previously, and <2.0 mg/kg thymoglobulin is recommended in terms of the balance between efficacy and adverse effects.

Efficacy of Mesenchymal Stem Cell Therapy for Steroid-Refractory Acute Graft-Versus-Host Disease following Allogeneic Hematopoietic Stem Cell Transplantation: A Systematic Review and Meta-Analysis

Background

Mesenchymal stem cells (MSCs) have been broadly used experimentally in various clinical contexts. The addition of MSCs to initial steroid therapy for acute graft-versus-host disease (aGVHD) may improve patient outcomes. However, investigations regarding prognostic factors affecting the efficacy of MSC therapy for steroid-refractory aGVHD remain controversial. We thus conducted a systematic review and meta-analysis of published clinical trials to determine possible prognostic factors affecting the efficacy of MSCs in treating steroid-refractory aGVHD.

Methods and Findings

Clinical trials using MSC therapy for steroid-refractory aGVHD were identified by searching PubMed and EMBASE databases. A total of 6,963 citations were reviewed, and 13 studies met the inclusion criteria. A total of 301 patients from thirteen studies were included. Of these, 136 patients showed a complete response (CR), and 69 patients displayed a partial (PR) or mixed response (MR). In total, 205 patients exhibited overall response (ORR). Patients with skin steroid-refractory aGVHD showed a better clinical response than gastrointestinal (CR: odds ratio [OR] = 1.93, 95% confidence interval [95%CI]: 1.05–3.57, p < 0.05) and liver (CR: OR = 2.30, 95%CI: 1.12–4.69, p < 0.05, and ORR: OR = 2.93, 95%CI: 1.06–8.08, p < 0.05) steroid-refractory aGVHD. Those with grade II steroid-refractory aGVHD exhibited a better clinical response following MSC therapy than recipients with grade III–IV (CR: OR = 3.22, 95%CI: 1.24–8.34, p < 0.05). Completion therapy may improve the CR but reduce ORR compared with induction therapy (CR: OR = 0.20, 95%CI: 0.09–0.44, p < 0.05; ORR: OR = 2.18, 95%CI: 1.17–4.05, p = 0.01). There was also a trend towards a better clinical response in children compared with adults (CR: OR = 2.41, 95%CI: 1.01–5.73, p = 0.05).

Conclusions

Age, skin involvement, lower aGVHD grade, and the number of infusions are the main prognostic factors affecting the efficacy of MSC therapy for steroid-refractory aGVHD.

Effects of T-Cell Depletion on Allogeneic Hematopoietic Stem Cell Transplantation Outcomes in AML Patients

Graft versus host disease (GVHD) remains one of the leading causes of morbidity and mortality associated with conventional allogeneic hematopoietic stem cell transplantation (HCT). The use of T-cell depletion significantly reduces this complication. Recent prospective and retrospective data suggest that, in patients with AML in first complete remission, CD34+ selected grafts afford overall and relapse-free survival comparable to those observed in recipients of conventional grafts, while significantly decreasing GVHD. In addition, CD34+ selected grafts allow older patients, and those with medical comorbidities or with only HLA-mismatched donors to successfully undergo transplantation. Prospective data are needed to further define which groups of patients with AML are most likely to benefit from CD34+ selected grafts. Here we review the history of T-cell depletion in AML, and techniques used. We then summarize the contemporary literature using CD34+ selection in recipients of matched or partially mismatched donors (7/8 or 8/8 HLA-matched), and provide a summary of the risks and benefits of using T-cell depletion.

Response-guided therapy for steroid-refractory acute GVHD starting with very-low-dose antithymocyte globulin

Treatment for steroid-refractory acute graft-versus-host disease (GVHD) has not been established yet. In this article, we report a single-center experience with rabbit antithymocyte globulin (ATG) for the treatment of steroid-refractory acute GVHD. We retrospectively analyzed 11 consecutive patients between December 2009 and December 2013. ATG was given at an initial dose of 1.0 mg/kg for all but one patient with gradual dose escalation while assessing responses. The overall improvement at day 28 was 55% after a median of two treatments (range: 1-5), and a median dose of 3 mg/kg (range: 1.0-11.75 mg/kg) of ATG. Patients with skin (100%, 3/3) and gut (83%, 5/6) responded favorably, whereas the cases with liver involvement showed poor responses (25%, 1/4). The overall survival and transplant-related mortality at 1 year were 55% and 45%, respectively. There were no patients who had developed a post-transplant lymphoproliferative disorder. We suggest that response-guided ATG therapy could be an option for patients with steroid-refractory GVHD, without increasing the incidence of opportunistic infections.

Clinicopathologic features of post-transplant lymphoproliferative disorders arising after pediatric small bowel transplant

Few studies examined the clinicopathologic features of PTLD arising in pediatric SBT patients. Particularly, the association between ATG and PTLD in this population has not been described. Retrospective review of 81 pediatric patient charts with SBT--isolated or in combination with other organs--showed a PTLD incidence of 11%, occurring more frequently in females (median age of four yr) and with clinically advanced disease. Monomorphic PTLD was the most common histological subtype. There was a significant difference in the use of ATG between patients who developed PTLD and those who did not (p < 0.01); a similar difference was seen with the use of sirolimus (p < 0.001). These results suggested a link between the combination of ATG and sirolimus and development of more clinically and histologically advanced PTLD; however, the risk of ATG by itself was not clear. EBV viral loads were higher in patients with PTLD, and median time between detection of EBV to PTLD diagnosis was three months. However, viral loads at the time of PTLD diagnosis were most often lower than at EBV detection, thereby raising questions on the correlation between decreasing viral genomes and risk of PTLD.

Current practice in diagnosis and treatment of acute graft-versus-host disease: results from a survey among German-Austrian-Swiss hematopoietic stem cell transplant centers

To assess current clinical practice in diagnosis and treatment of acute graft-versus-host disease (aGVHD), we performed a survey among German, Austrian, and Swiss allogeneic hematopoietic stem cell transplantation (allo-HSCT) centers. Thirty-four of 72 contacted centers (47%) completed both the diagnostic and therapeutic sections of the survey, representing 65% of allo-HSCT activity within the participating countries in 2011. Three pediatric centers answered as requested only the diagnostic part of the survey. In the presence of diarrhea and decreased oral intake after engraftment, only 4 centers (12%) do not perform any endoscopy before the start of immunosuppressive treatment. In case of a skin rash with the differential diagnosis of drug reaction, only 12 centers (35%) perform a skin biopsy up front, whereas 19 do so after failure of systemic steroids. In the presence of rapidly increasing cholestasis occurring without any other signs of aGVHD, 11 centers (32%) perform a liver biopsy up front and 14 only after failure of steroid treatment, whereas 9 centers do not perform a liver biopsy at all. Twenty centers (59%) use a percutaneous approach, 12 a transvenous approach, and 1 mini-laparoscopy for liver biopsies. First-line treatment of cutaneous aGVHD stage 1 consists of topical treatment alone in 17 of 31 responding centers (61%), whereas isolated cutaneous aGVHD stage III is treated with systemic steroids (prednisolone below 0.5 mg/kg/day n = 2, 0.5 to 1.0 mg/kg/day n = 10, above 1.0 to 2.5 mg/kg/day n = 19) without or with topical agents (steroids n = 10; calcineurin inhibitors n = 3). In gastrointestinal manifestations of aGVHD, 9 centers (29%) add topical to systemic steroids, and 3 consider topical steroids as the only treatment for mild gastrointestinal and cutaneous aGVHD. The choice of agent for second-line treatment as well as the sequence of administration are extremely heterogeneous, most likely due to a lack of convincing data published. Most frequently used are mycophenolate mofetil (n = 14) and extracorporeal photopheresis (n = 10). Our survey also demonstrates that clinicians chose salvage therapies for steroid-refractory aGVHD based on their centers' own clinical experience.

Secondary treatment of acute graft-versus-host disease: a critical review

Management of steroid-resistant or steroid-refractory acute graft-versus-host disease (aGVHD) poses one of the most vexing and difficult problems faced by transplantation physicians. In the current study, we used 10 criteria to evaluate 67 reports describing secondary treatment of patients with aGVHD. The goal of this exercise was not only to provide a critical summary of the literature but also to offer suggestions that could improve future studies. Areas especially in need of improvement include the use of a consistent treatment regimen, the assessment of response at a consistent prespecified time point, consideration of concomitant treatment in assessing response, documentation that selection bias was minimized, and the use of methods that test a formal statistical hypothesis based on a contemporaneous or historical benchmark. Our results suggest that previous published reports collectively offer little guidance in discerning the most effective treatments for patients with steroid-resistant or steroid-refractory aGVHD. Adherence to the proposed criteria in future reports would enable meaningful comparisons across studies and thereby accelerate progress in evaluating new treatments for patients with aGVHD.

Rabbit antithymocyte globulin (thymoglobulin): 25 years and new frontiers in solid organ transplantation and haematology

The more than 25 years of clinical experience with rabbit antithymocyte globulin (rATG), specifically Thymoglobulin, has transformed immunosuppression in solid organ transplantation and haematology. The utility of rATG has evolved from the treatment of allograft rejection and graft-versus-host disease to the prevention of various complications that limit the success of solid organ and stem cell transplantation. Today, rATG is being successfully incorporated into novel therapeutic regimens that seek to reduce overall toxicity and improve long-term outcomes. Clinical trials have demonstrated the efficacy and safety of rATG in recipients of various types of solid organ allografts, recipients of allogeneic stem cell transplants who are conditioned with both conventional and nonconventional regimens, and patients with aplastic anaemia. Over time, clinicians have learnt how to better balance the benefits and risks associated with rATG. Advances in the understanding of the multifaceted mechanism of action will guide research into new therapeutic areas and future applications.

The gastrointestinal complications of oncologic therapy

A spectrum of oncologic treatments including chemotherapy, radiotherapy, and molecular targeted therapies is available to combat cancer. These treatments are associated with adverse effects in several organ systems including the gastrointestinal (GI) tract. The immunocompromised state induced by oncologic therapy is also an important contributing factor underlying GI complications. This review discusses common GI complications that can result from cancer therapy. The pathologic mechanisms underlying each complication and the pharmacology of the agents used to treat these complications are discussed.

Management of acute graft-versus-host disease in children

Acute graft-versus-host disease (aGVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT) in children. Although 30% to 50% of children respond to corticosteroids as initial therapy, the optimal initial or second-line therapies have not yet been determined. Newer approaches with combination therapy, novel agents, monoclonal antibodies, and/or cellular therapies show some promise but require prospective well-designed trials that include children to establish their efficacy. This article reviews the clinical presentation, treatment, and practical management guidelines for children with aGVHD.

Rapamycin for refractory acute graft-versus-host disease

BACKGROUND

Rapamycin, an inhibitor of mammalian target of rapamycin kinase, is a potent immunosuppressive drug that also displays antineoplastic properties and expands regulatory T cells. Steroid-refractory acute graft-versus-host disease (GVHD) remains a significant cause of mortality after allogeneic stem-cell transplantation and therapeutic options are not codified. We retrospectively evaluated the role of rapamycin in this setting.

METHODS

In this retrospective single-center study, 22 patients were identified, from October 2004 to February 2008, as having received rapamycin for acute GVHD refractory to one or more lines of treatment. We analyzed the efficacy and tolerance of rapamycin and the outcome of these 22 patients in this setting.

RESULTS

Rapamycin resulted in a rapid and sustained complete remission of GVHD in 72% of heavily pretreated patients. Cytopenias were frequent but did not require treatment interruption. Thrombotic microangiopathy developed in 36% of patients when rapamycin was associated with calcineurin inhibitors and frequently resolved after interruption of one or both drugs. At a median follow-up of 13 months, overall survival was 41%. Previous treatment with high-dose steroid pulses was associated with a worse outcome (survival 12% vs. 69%). The major cause of death was infectious complications (77%).

CONCLUSION

Despite a small and heterogeneous population of patients, these results are encouraging and provide a rationale for prospective studies that use rapamycin in steroid-refractory acute GVHD as a second- or third-line agent.

Acute graft-versus-host disease: new treatment strategies

PURPOSE OF REVIEW

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT), despite improvements in our understanding of its pathophysiology as well as the generation of new monoclonal antibodies, immunomodulatory chemotherapy, cellular therapeutics and supportive care. Herein, we review therapies that have proven effective as well as newer agents that have recently improved GVHD response rates and survival following HCT.

RECENT FINDINGS

Novel approaches to prevent or treat GVHD are often based on evidence from experimental models. Our understanding of the pathophysiology of GVHD may lead to the development of innovative strategies that target both soluble and cellular effectors. Among such agents are sirolimus, anti-tumor necrosis factor antibodies, anti-LFA-3-IgG fusion protein, extracorporeal photopheresis, mesenchymal stem cells and regulatory T cells.

SUMMARY

Obstacles to the improvement of HCT include the tight linkage between GVHD toxicity and the beneficial graft-versus-leukemia (GVL) effect, as well as the impairment of immune reconstitution by immunomodulatory drugs leading to life-threatening infections. The design of newer phase I/II clinical trials are underway. Future therapies are likely to include modulation of cell types that play key roles in the GVH process, including regulatory T cells, dendritic cells, natural killer T cells and B cells.

Endpoints for clinical trials testing treatment of acute graft-versus-host disease: a joint statement

Currently, no agents are approved by the United States Food and Drug Administration (FDA) for either prevention or treatment of acute graft-versus-host disease (aGVHD). Formal precedents establishing a comparative basis for assessing the efficacy and safety of new investigational agents are still lacking. As a step toward addressing this problem, a panel of experts met on 2 occasions to reach consensus on recommendations for terminology describing a clinically meaningful primary endpoint in studies assessing treatment for aGVHD. The panel recommended terminology for "very good partial response" (VGPR) that includes both diagnostic and functional criteria. The central hypothesis leading to this proposal is that the potential harm of giving more treatment than needed to produce or maintain complete response exceeds the harm of slight undertreatment that may be associated with less than complete response. VGPR clearly cannot be used as the sole outcome measure in GVHD treatment trials, and must be considered in the context of survival and safety. The proposed use of VGPR as the primary endpoint in GVHD treatment trials will remain provisional until its use has been validated through experience.

Graft-versus-host disease

Haemopoietic-cell transplantation (HCT) is an intensive therapy used to treat high-risk haematological malignant disorders and other life-threatening haematological and genetic diseases. The main complication of HCT is graft-versus-host disease (GVHD), an immunological disorder that affects many organ systems, including the gastrointestinal tract, liver, skin, and lungs. The number of patients with this complication continues to grow, and many return home from transplant centres after HCT requiring continued treatment with immunosuppressive drugs that increases their risks for serious infections and other complications. In this Seminar, we review our understanding of the risk factors and causes of GHVD, the cellular and cytokine networks implicated in its pathophysiology, and current strategies to prevent and treat the disease. We also summarise supportive-care measures that are essential for management of this medically fragile population.

Therapy with mycophenolate mofetil for refractory acute and chronic GVHD

We evaluated the pharmacokinetics and efficacy of oral mycophenolate mofetil (MMF) for treatment of refractory graft-versus-host disease (GVHD). In a prospective study of acute GVHD, 9 of 19 patients (47%) had a response and 10 (53%) had no improvement. Survival at 6 and 12 months after the start of MMF was 37% and 16%, respectively. In a retrospective study of acute GVHD, 14 of 29 patients (48%) had a response and 15 (52%) had no improvement. Survival at 6 and 12 months was 55% and 52%, respectively. In a prospective study of chronic GVHD, the cumulative incidence of disease resolution and withdrawal of all systemic immunosuppressive treatment was 9%, 17% and 26% at 12, 24 and 36 months after starting MMF, respectively. Thirteen patients (59%) required additional systemic immunosuppressive treatment for chronic GVHD. Nine of the 42 patients (21%) in the prospective studies discontinued MMF treatment because of toxicity. Area under the curve plasma concentrations of mycophenolic acid appeared to be suboptimal among patients with acute GVHD but not among those with chronic GVHD. MMF can be used effectively for treatment of GVHD.

Total and active rabbit antithymocyte globulin (rATG;Thymoglobulin) pharmacokinetics in pediatric patients undergoing unrelated donor bone marrow transplantation

Rabbit antithymocyte globulin (rATG; Thymoglobulin) is currently used to prevent or treat graft-versus-host disease (GVHD) during hematopoietic stem cell transplantation (HSCT). The dose and schedule of rATG as part of the preparative regimen for unrelated donor (URD) bone marrow transplantation (BMT) have not been optimized in pediatric patients. We conducted a prospective study of 13 pediatric patients with hematologic malignancies undergoing URD BMT at St. Jude Children's Research Hospital from October 2003 to March 2005, to determine the pharmacokinetics and toxicities of active and total rATG. The conditioning regimen comprised total body irradiation (TBI), thiotepa, and cyclophosphamide (Cy); cyclosporine (CsA) and methotrexate (MTX) were administered as GVHD prophylaxis. Patients received a total dose of 10 mg/kg rATG, and serial blood samples were assayed for total rATG by enzyme linked immunosorbent assay (ELISA) and active rATG by florescein activated cell sorting (FACS). We found that our weight-based dosing regimen for rATG was effective and well tolerated by patients. The half-lives of total and active rATG were comparable to those from previous studies, and despite high doses our patients had low maximum concentrations of active and total rATG. There were no occurrences of grade iii-iv GVHD even in patients having low peak rATG levels, and the overall incidence of grade II GVHD was only 15%. None of the patients had serious infections following transplantation. These data support the use of a 10 mg/kg dose of rATG in children with hematologic malignancies because it can be administered without increasing the risk of graft rejection, or serious infection in pediatric patients with a low rate of GVHD. These conclusions may not apply to patients with nonmalignant disorders.

Favorable response to human adipose tissue-derived mesenchymal stem cells in steroid-refractory acute graft-versus-host disease

There is no consistently effective therapy for patients with steroid-refractory acute graft-versus-host disease (GVHD). Various alternative approaches have been tested, including antithymocyte globulin, mycophenolate mofetil (MMF), pentostatin, and monoclonal antibodies; however, they have only been modestly successful. The purpose of our study was to evaluate the efficacy of human adipose-tissue-derived mesenchymal stem cells (AMSC) as salvage therapy for steroid-refractory acute GVHD. Six patients with steroid-refractory grades III-IV acute GVHD received IV infusions of AMSC. The AMSC dose was 1.0x10(6)/kg. No side effects were noted after the AMSC infusions. Five patients were treated once and one patient twice. Two patients received AMSC from haplo-identical family donors and four from unrelated mismatched donors. Acute GVHD disappeared completely in five of six patients, four of whom are alive after a median follow-up of 40 months (range, 18-90 months) after the initiation of AMSC therapy. All four surviving patients are in good clinical condition and in remission of their hematological malignancy. Two patients died-one with no obvious response to AMSC died of multiorgan failure and one a relapse of leukemia. These results suggested that AMSC is a promising treatment for severe steroid-resistant acute GVHD.

Graft versus host disease after liver transplantation - a single center experience and review of literature

Graft versus host disease (GvHD) after liver transplantation has an incidence of 0.1-1%. It is an infrequent but severe and mostly lethal complication. Approximately, 80 cases have been reported in literature so far. A single center experience is reported retrospectively. We performed a retrospective analysis of 1815 liver transplants in our center, transplanted over a period of 17 years. Five patients (5/1815 = 0.28%) with histologically diagnosed GvHD were included in the analysis. Onset of GvHD was between postoperative day (POD) 20 and 60. All patients developed skin rash, being the first symptom in four cases; one patient had joint pain as initial symptom. Macrochimerism was confirmed in all patients. Treatment consisted of augmentation of baseline immunosuppression (n = 4), methylprednisolone (n = 4), and T-cell depleting antibodies (n = 3). One patient received no specific therapy because of her deleterious condition. All patients died because of either haemorrhage or uncontrollable infections. In our experience, GvHD has been an extremely rare, albeit deleterious clinical condition, which was resistant to classical immunosuppressive rescue regimens.

Human adipose tissue-derived mesenchymal stromal cells as salvage therapy for treatment of severe refractory acute graft-vs.-host disease in two children

Severe GVHD is a lethal complication to ASCT, and a number of approaches are therefore being evaluated. Recently, Le Blanc et al. reported a case of grade IV therapy-resistant acute GVHD of the gut and liver that showed rapid improvement after infusion of mesenchymal stem cells. Here we describe two pediatric patients who developed severe refractory acute GVHD following ASCT and were successfully treated with AMSC from HLA-mismatched unrelated donors.

Graft vs. host disease after liver transplantation: a new approach is needed

Graft-vs.-host disease (GVHD) is a rare, serious complication of orthotopic liver transplantation (OLT). We have treated 5 patients to date with GVHD after OLT. A total of 78 patients worldwide have been reported to have experienced this complication. The means by which GVHD after OLT has been managed is guided by experience with the more common GVHD that occurs after stem cell transplantation. However, despite the use of various treatment modalities, the mortality of GVHD after OLT remains high. This case series and review of the literature demonstrates that successful resolution of GVHD after OLT cannot be expected with the use of those modalities that have been tried to date. It is imperative that new treatments be applied to GVHD after OLT in order to improve the prognosis of patients with this diagnosis.

Long-term follow-up of patients treated with daclizumab for steroid-refractory acute graft-vs-host disease

Daclizumab has been shown to have activity in acute GVHD, but appears to be associated with an increased risk of infection. To investigate further the long-term effects of daclizumab, we performed a retrospective review of 57 patients who underwent an allogeneic hematopoietic stem cell transplant from January 1993 through June 2000 and were treated with daclizumab for steroid-refractory acute GVHD. The median number of daclizumab doses given was 5 (range 1-22). GVHD was assessed at baseline, days 15, 29 and 43. By day 43, 54% patients had an improvement in their overall GVHD score, including 76% patients aged < or =18. Opportunistic infections developed in 95% patients. Forty-three patients (75%) died following treatment with daclizumab. The causes of death included active GVHD and infection (79%), active GVHD (5%), chronic GVHD (2%) and relapse (14%). Patients with grade 3-4 GVHD had a significantly shorter median survival than patients with grade 1-2 GVHD (2.0 vs 5.1 months, P=0.001). Daclizumab has no infusion-related toxicity, is active in steroid-refractory GVHD, especially among pediatric patients, but is associated with significant morbidity and mortality due to infectious complications. Careful patient selection and aggressive prophylaxis against viral and fungal infections are recommended.

Reduced incidence of acute and chronic graft-versus-host disease with the addition of thymoglobulin to a targeted busulfan/cyclophosphamide regimen

To reduce the incidence of graft-versus-host disease (GVHD), we added Thymoglobulin (THY) to dose-adjusted oral busulfan plus cyclophosphamide (targeted BUCY). The starting dose of THY was 4.5 mg/kg given over days -3, -2, and -1, escalated in steps of 1.5 mg/kg in cohorts of 15 evaluable patients. Escalation was dependent on acute GVHD incidence and Epstein-Barr virus reactivation. Fifty-six patients with myelodysplastic syndrome and other myeloid disorders underwent transplantation with peripheral blood progenitor cells from related (n=30) or unrelated (n=26) donors. All but 2 patients achieved engraftment, and 56% survived in remission beyond 1 year. The incidence of acute GVHD was 50%, and that of chronic GVHD was 34%. The highest THY dose was 6.0 mg/kg, a dose at which 1 patient experienced Epstein-Barr virus reactivation. Nine patients did not receive the prescribed THY dose. Results were comparable for related and unrelated transplants and for patients given 4.5 or 6.0 mg/kg THY. Among 27 myelodysplastic syndrome patients (14 with related and 13 with unrelated donors) who underwent transplantation concurrently with targeted BUCY without THY, the incidence of acute and chronic GVHD was 82%. Thus, THY 4.5 to 6.0 mg/kg seemed beneficial for GVHD prevention in BUCY-conditioned patients who underwent transplantation with peripheral blood progenitor cells, although relapse-free survival did not differ significantly from that in comparable historical controls not given THY.

OKT3 muromonab as second-line and subsequent treatment in recipients of stem cell allografts with steroid-resistant acute graft-versus-host disease

We retrospectively evaluated response to monoclonal antibody directed against CD3 (OKT3) treatment in 43 patients with steroid-resistant acute graft-versus-host disease (aGvHD) following allogeneic hematopoietic cell transplantation. Median duration of OKT3 therapy was 9 (range, 1-20) days. In all, 20 cycles were administered as second-line and 28 as third-plus line treatment. Side effects were mild to moderate. Overall response rate was 69 with 12% complete remissions and best response in skin involvement. Proportional reduction of concomitant steroids was higher in responding patients. Five patients (12%) achieved durable responses. Pharmacokinetic studies of OKT3 showed adequate plasma levels (> or = 1000 ng/ml) in 13 of 17 evaluable patients after a median of 6 (1-11) days on treatment. OKT3 became undetectable shortly after discontinuation of therapy. Median survival for all patients was 80 (2 to 2474+) days. There was a trend for better survival for patients on second-line vs third-plus line treatment (146 vs 46 days; P=0.07) and significant longer survival for patients with grade II when compared to those with grade III/IV aGvHD (206 vs 47 days; P=0.039). We conclude that salvage treatment with OKT3 shows considerable efficiency, however, sometimes of transient nature, and is well tolerated in patients with corticosteroid-resistant aGvHD.

A phase II multicenter study of visilizumab, humanized anti-CD3 antibody, to treat steroid-refractory acute graft-versus-host disease

Results of a previous phase I study suggested that a single 3 mg/m2 dose of the humanized non-FcR-binding anti-CD3 monoclonal antibody visilizumab (Nuvion) was well tolerated and had efficacy for the treatment of steroid-refractory acute graft-versus-host disease (GVHD). We now report results of a multicenter phase II study in which visilizumab was given to 44 participants with steroid-refractory acute GVHD. Eighty-two percent of the participants had visceral involvement, and 86% had overall grade III or IV acute GVHD at study entry. The respective complete and overall response rates were 14% and 32% at 42 days. Plasma Epstein-Barr virus DNA increased to more than 1000 copies per milliliter in 19 subjects. Seventeen received rituximab, and no fatal lymphoproliferative disorders were observed. Survival at 180 days was 32% (95% confidence interval, 18%-46%). The administration of visilizumab as used in this study seems to be sufficiently safe and effective to warrant further assessment for treatment or prevention of GVHD.

Pulse cyclophosphamide for corticosteroid-refractory graft-versus-host disease

Corticosteroid-resistant GVHD is difficult to manage and is associated with high morbidity and mortality. Cyclophosphamide (Cy) is an established immunosuppressive and cytotoxic drug widely used as part of pretransplant conditioning regimens. In a retrospective study of 15 patients who had not responded to corticosteroids (nine with acute GVHD, three with GVHD after donor leukocyte infusion, and three progressive chronic GVHD), pulse Cy at a median dose of 1 g/m(2) was very effective in the treatment of skin (100% response), liver (70% response), and the oral cavity (100% response). Severe intestinal GVHD responded poorly. The toxicity profile was acceptable, with manageable, short-term myelosuppression in some patients. The risk of opportunistic infections, mixed chimerism, relapses, or post-transplant lymphoproliferative disease was not increased. Overall survival was 57%, with median and maximum follow-up of 9 and 37 months, respectively. The cost of the drug was negligible, especially when compared to monoclonal antibodies. Pulse Cy requires further investigation in corticosteroid-resistant GVHD.

Mycophenolate mofetil for the treatment of acute and chronic steroid-refractory graft-versus-host disease

Corticosteroid-resistant graft-versus-host disease (GvHD) is difficult to manage and is associated with high morbidity and mortality. The purpose of our study was to evaluate the safety and efficacy of mycophenolate mofetil (MMF) as the salvage therapy for steroid-refractory GvHD. Twenty one patients (10 with acute GvHD and 11 with chronic GvHD) were studied retrospectively. Steroid-resistant GvHD was defined as acute or chronic GvHD not responding to a first-line regimen of cyclosporine A and corticosteroids in a dose equivalent to 2 mg/kg methylprednisolone for at least 7 days. MMF was added at a dose of 2 g daily, and corticosteroids were tapered. Thirteen (62%) of 21 patients responded to the treatment with MMF, including 6 (60%) of 10 patients with acute refractory GvHD and 7 (64%) of 11 patients with chronic refractory GvHD. The most common adverse effects were infectious complications (67%, 14 of 21 patients) and hematological toxicity (29%, 6 of 21 patients). Median duration of MMF administration was 6 months (range 1-27 months). Sixteen of 21 patients were alive after the median follow-up of 27 months (range 1-72 months) after the initiation of MMF therapy. All 16 surviving patients were in good clinical condition and in remission of their hematological malignancy. Five patients died--two of relapses of leukemia and three of refractory intestinal GvHD. These results suggest that MMF can be an effective treatment for some cases of steroid-refractory GvHD.

Treatment of steroid-resistant acute graft-versus-host disease with daclizumab and etanercept

Steroid-resistant acute GVHD (aGVHD) following allogeneic hematopoietic stem cell transplantation (alloHSCT) continues to be associated with a high mortality. We report the results of a phase II study of treatment of steroid-resistant aGVHD with the IL-2 receptor antibody daclizumab combined with the TNF-receptor fusion protein etanercept. Treatment consisted of daclizumab 1 mg/kg given i.v. on days 1, 4, 8, 15, 22 and etanercept 16 mg/m(2) s.c. on days 1, 5, 9, 13, 17. A total of 21 patients (age 15-61 years) with steroid-resistant aGVHD after alloHSCT were included in the study. Donor types were HLA-matched related (n=6), HLA-matched unrelated (n=14), and HLA-mismatched unrelated (n=1). Eight patients achieved complete, and six showed partial remission of aGVHD. Seven patients did not respond. Four of 21 patients are currently alive with a median follow-up of 586 (185-1155) days. Three patients died due to relapsed malignancy. Treatment-related mortality was due to infectious complications (n=11) or organ failure due to aGVHD (n=3). In total, 12 patients developed subsequent chronic GVHD. In conclusion, the data demonstrate an acceptable response rate of the combination of daclizumab and etanercept in the treatment of steroid-resistant aGVHD. Nevertheless, long-term mortality due to infectious complications and chronic GVHD remains high.

Emerging therapies for graft-versus-host disease

Acute graft-versus-host disease (GVHD) and chronic GVHD remain the major barriers to successful haematopoietic cell transplantation. The induction of GVHD may be divided into three phases: (i) recipient conditioning, (ii) donor T cell activation, and (iii) effector cells mediating GVHD. Standard agents and agents under development to prevent and treat GVHD are discussed. The various pharmacological agents impact on different phases of the GVHD cascade. Sirolimus is a new immunophilin binding agent that appears to be synergistic with tacrolimus and cyclosporin. It also seems to promote allograft tolerance. Mycophenolate mofetil (MMF) is an antimetabolite that is currently under study for prophylaxis and treatment of acute and chronic GVHD; results are encouraging. Other agents such as the purine analogue pentostatin and the monoclonal antibodies alemtuzumab, daclizumab and infliximab are discussed at length within the GVHD context. The most effective approach to GVHD prevention will likely be a combination regimen where the three phases of the GVHD cascade are disrupted. Once GVHD has occurred, all three phases of the cascade are activated. Developments of combination therapy for the treatment of both acute and chronic GVHD will likely yield better results than monotherapy. The numerous new treatment modalities presented should improve the outlook for acute and chronic GVHD.

Improved survival in steroid-refractory acute graft versus host disease after non-myeloablative allogeneic transplantation using a daclizumab-based strategy with comprehensive infection prophylaxis

Approximately 15% of patients undergoing non-myeloablative allogeneic haematopoietical cell transplantation (NMHCT) develop steroid-refractory acute-graft versus host disease (aGVHD), a usually fatal complication. We encountered 18 cases of steroid-refractory aGVHD in 146 patients, undergoing NMHCT from a related human leucocyte antigen-compatible donor following cyclophosphamide/fludarabine-based conditioning. Our initial cohort of steroid-refractory aGVHD patients treated with antithymocyte globulin (ATG) and mycophenolate mofetil (regimen-1: n = 6) had high GVHD-related mortality. Therefore, we investigated an alternative strategy for subsequent patients developing this complication (regimen-2: n = 12), consisting of daclizumab (alone or combined with infliximab/ATG) and targeted broad spectrum antibacterial and aspergillus prophylaxis in conjunction with rapid tapering of steroids to minimize opportunistic infections. In a retrospective analysis, patients receiving regimen-2 were significantly more likely to have complete resolution of GVHD compared with those receiving regimen-1 [12/12 (100%) vs. 1/6 (17%); P < 0.001]. When compared with those receiving regimen-1, regimen-2 patients also had a higher probability of survival at day 100 (100% vs. 50%) and day 200 (73% vs. 17%) post-transplant, and improved overall survival (median 453 d vs. 42 d from aGVHD onset; P < 0.0001). GVHD-related mortality was 89% for regimen-1 patients vs. 17% for regimen-2 patients (P < 0.0001). These data suggest that a co-ordinated approach using immunoregulatory monoclonal antibodies, pre-emptive antimicrobial therapy and judicious steroid withdrawal can dramatically improve outcome in steroid-refractory aGVHD.

Acute graft versus host disease following liver transplantation: the enemy within

This article reviews acute graft vs. host disease (GVHD) as a complication of orthotopic liver transplantation (OLT). The incidence, presentation, clinical course and outcome of GVHD after OLT are summarized and the pathogenesis is discussed, drawing parallels with GVHD after allogeneic haematopoietic stem cell transplantation. Risk factors for GVHD after OLT are examined and the potential role of donor lymphocyte macrochimerism in the recipient peripheral blood as a diagnostic aid for GVHD is discussed. Finally, treatment of GVHD after OLT is reviewed with particular emphasis on the potential role of some of the newer biological agents.

Epstein-Barr virus-associated posttransplantation lymphoproliferative disorder after high-dose immunosuppressive therapy and autologous CD34-selected hematopoietic stem cell transplantation for severe autoimmune diseases

High-dose immunosuppressive therapy followed by autologous hematopoietic stem cell transplantation (HSCT) is currently being evaluated for the control of severe autoimmune diseases. The addition of antithymocyte globulin (ATG) to high-dose chemoradiotherapy in the high-dose immunosuppressive therapy regimen and CD34 selection of the autologous graft may induce a higher degree of immunosuppression compared with conventional autologous HSCT for malignant diseases. Patients may be at higher risk of transplant-related complications secondary to the immunosuppressed state, including Epstein-Barr virus (EBV)-associated posttransplantation lymphoproliferative disorder (PTLD), but this is an unusual complication after autologous HSCT. Fifty-six patients (median age, 42 years; range, 23-61 years) with either multiple sclerosis (n = 26) or systemic sclerosis (n = 30) have been treated. The median follow-up has been 24 months (range, 2-60 months). Two patients (multiple sclerosis, n = 1; systemic sclerosis, n = 1) had significant reactivations of herpesvirus infections early after HSCT and then developed aggressive EBV-PTLD and died on days +53 and +64. Multiorgan clonal B-cell infiltrates that were EBV positive by molecular studies or immunohistology were identified at both autopsies. Both patients had positive screening skin tests for equine ATG (Atgam) and had been converted to rabbit ATG (Thymoglobulin) from the first dose. Of the other 54 patients, 2 of whom had partial courses of rabbit ATG because of a reaction to the intravenous infusion of equine ATG, only 1 patient had a significant clinical reactivation of a herpesvirus infection (herpes simplex virus 2) early after HSCT, and none developed EBV-PTLD. The T-cell count in the peripheral blood on day 28 was 0/microL in all 4 patients who received rabbit ATG; this was significantly less than in patients who received equine ATG (median, 174/microL; P =.001; Mann-Whitney ranked sum test). Although the numbers are limited, the time course and similarity of the 2 cases of EBV-PTLD and the effect on day 28 T-cell counts support a relationship between the development of EBV-PTLD and the administration of rabbit ATG. The differences between equine and rabbit ATG are not yet clearly defined, and they should not be considered interchangeable in this regimen without further study.

Steroid-refractory graft-vs.-host disease: past, present and future

Despite current standard preventive strategies that include optimizing donor selection and the combination of methorexate and a calcineurine inhibitor, acute and chronic GVHD remains a major barrier to successful hematopoietic cell transplantation for a sizeable proportion of patients. When acute and chronic GVHD become manifest a standard primary therapy approach has been the addition of glucocorticoid therapy to a background of calcineurine inhibition. When this approach fails patients with GVHD require secondary therapy. Ideally, second-line agents should promote transplantation tolerance so that the morbidity associated with prolonged use of glucocorticoids and other immunosuppressive agents can be minimized. Promising new agents or strategies which warrant further controlled clinical trials include: mycophenolate mofetil, sirolimus, humanized or chimeric monoclonal antibodies such as visilizumab, daclizumab and infliximab, and extracorporeal photopheresis. Co-operative studies are necessary to hasten the process of evaluating novel treatment strategies for acute and chronic GVHD.

High-dose immunosuppressive therapy for severe systemic sclerosis: initial outcomes

Systemic sclerosis (SSc) is a multisystem disease of presumed autoimmune pathogenesis for which no proven effective treatment exists. High-dose immunosuppressive therapy (HDIT) has been proposed as an investigational treatment for severe autoimmune diseases. Nineteen patients with poor-prognosis SSc underwent HDIT. The median age was 40 years (range, 23-61 years), the median modified Rodnan skin score (a measure of dermal sclerosis) was 31, and the median DLCO was 57%. Conditioning therapy involved 800 cGy total body irradiation (TBI) (± lung shielding to approximately 200 cGy), 120 mg/kg cyclophosphamide, and 90 mg/kg equine antithymocyte globulin. CD34-selected granulocyte–colony-stimulating factor–mobilized autologous blood stem cells provided hematopoietic rescue. With median follow-up at 14.7 months, the Kaplan-Meier estimated 2-year survival rate was 79%. Three patients died of treatment complications and one of disease progression. Two of the first 8 patients had fatal regimen-related pulmonary injury, a complication not found among 11 subsequent patients who received lung shielding for TBI. Overall, internal organ functions were stable to slightly worse after HDIT, and 4 patients had progressive or nonresponsive disease. As measured by modified Rodnan skin scores and modified health assessment questionnaire disability index (mHAQ-DI) scores, significant disease responses occurred in 12 of 12 patients evaluated at 1 year after HDIT. In conclusion, though important treatment-related toxicities occurred after HDIT for SSc, modifications of initial approaches appear to reduce treatment risks. Responses in skin and mHAQ-DI scores exceed those reported with other therapies, suggesting that HDIT is a promising new therapy for SSc that should be evaluated in prospective randomized studies.

A humanized non-FcR-binding anti-CD3 antibody, visilizumab, for treatment of steroid-refractory acute graft-versus-host disease

Visilizumab is a humanized anti-CD3 monoclonal antibody characterized by a mutated IgG2 isotype, lack of binding to Fcgamma-receptors, and ability to induce apoptosis selectively in activated T cells. To test pharmacokinetics, safety, and immunosuppressive activity of visilizumab, 17 patients with glucocorticoid-refractory acute graft-versus-host disease (GVHD) were enrolled in a phase 1 study. Six patients were given 7 doses of visilizumab (0.25 or 1.0 mg/m(2)) on days 1, 3, 5, 7, 9, 11, and 13. Because multiple doses of 1 mg/m(2) caused delayed visilizumab accumulation and prolonged lymphopenia, the next 11 patients received a single dose of 3.0 mg/m(2) on day 1. GVHD improved in all patients; 15 were evaluable through day 42. Multiple dosing resulted in 1 of 6 complete responses (CRs) and 5 partial responses (PRs), but all 6 patients died at a median of 87 days after starting visilizumab therapy. Single dosing resulted in 6 of 9 CRs, 3 PRs, and 7 of 11 patients surviving after 260 to 490 days (median, 359 days; P =.03). There were no allergic reactions and 3 grade 1 acute infusional toxicities. Plasma Epstein-Barr virus (EBV) DNA titers more than 1000 copies/mL and posttransplant lymphoproliferative disease (PTLD) developed in 2 of the first 7 patients. Based on rising EBV DNA titers, 5 of the next 10 patients were given the B cell-specific monoclonal antibody, rituximab. EBV DNA became undetectable and no overt PTLD developed. Visilizumab is well tolerated and has activity in advanced GVHD. A phase 2 study incorporating preemptive therapy for PTLD is warranted to determine the efficacy of visilizumab in GVHD.