Tumor necrosis factor-alpha blockade for the treatment of acute GVHD

Etanercept plus methylprednisolone as initial therapy for acute graft-versus-host disease

Graft-versus-host disease (GVHD) is a principal cause of morbidity following allogeneic hematopoietic cell transplantation (HCT). Standard therapy for GVHD, high-dose steroids, results in complete responses (CRs) in 35% of patients. Because tumor necrosis factor-alpha (TNFalpha) is an important effector of experimental GVHD, we treated patients with new-onset GVHD with steroids plus the TNFalpha inhibitor etanercept on a previously reported pilot trial (n = 20) and a phase 2 trial (n = 41). We compared their outcomes with those of contemporaneous patients with GVHD (n = 99) whose initial therapy was steroids alone. Groups were similar with respect to age, conditioning, donor, degree of HLA match, and severity of GVHD at onset. Patients treated with etanercept were more likely to achieve CR than were patients treated with steroids alone (69% vs 33%; P < .001). This difference was observed in HCT recipients of both related donors (79% vs 39%; P = .001) and unrelated donors (53% vs 26%; P < .001). Plasma TNFR1 levels, a biomarker for GVHD activity, were elevated at GVHD onset and decreased significantly only in patients with CR. We conclude that etanercept plus steroids as initial therapy for acute GVHD results in a substantial majority of CRs. This trial was referenced at www.clinicaltrials.gov as NCT00141713.

Anti-tumor necrosis factor-a for the treatment of steroid-refractory acute graft-versus-host disease

Allogeneic stem cell transplantation has been increasingly performed for a variety of hematologic diseases. Clinically significant acute graft-versus-host disease (GVHD) occurs in 9 to 50% of patients who receive allogeneic grafts, resulting in high morbidity and mortality. There is no standard therapy for patients with acute GVHD who do not respond to steroids. Studies have shown a possible benefit of anti-TNF-a (infliximab)for the treatment of acute GVHD. We report here on the outcomes of 10 recipients of related or unrelated stem cell transplants who received 10 mg/kg infliximab, iv, once weekly for a median of 3.5 doses (range: 1-6) for the treatment of severe acute GVHD and who were not responsive to standard therapy. All patients had acute GVHD grades II to IV (II = 2, III = 3, IV = 5). Overall, 9 patients responded and 1 patient had progressive disease. Among the responders, 3 had complete responses and 6 partial responses. All patients with cutaneous or gastrointestinal involvement responded, while only 2 of 6 patients with liver disease showed any response. None of the 10 patients had any kind of immediate toxicity. Four patients died, all of them with sepsis. Six patients are still alive after a median follow-up time of 544 days (92-600) after transplantation. Considering the severity of the cases and the bad prognosis associated with advanced acute GVHD, we find our results encouraging. Anti-TNF-a seems to be a useful agent for the treatment of acute GVHD.

Terapia biológica con anticuerpos anti factor de necrosis tumoral, ¿ampliando el espectro de sus indicaciones?

Tumor necrosis factor (TNFalpha) is a main mediator in the inflammatory answer of many diseases. The anti-TNFalpha antibodies (infliximab, etanercept, adalimumab) block their action, preventing the inflammatory answer and the damage it produces. In this paper, we review the treatment of some diseases in which these drugs are experimentally used. These are: ulcerative colitis, sarcoidosis, graft-versus-host disease, adult Still's disease, some systemic vasculitis, systemic lupus erythematosus and Behçet disease.

Acute graft versus host disease

Acute graft-versus-host disease (GVHD) occurs after allogeneic hematopoietic stem cell transplant and is a reaction of donor immune cells against host tissues. Activated donor T cells damage host epithelial cells after an inflammatory cascade that begins with the preparative regimen. About 35%-50% of hematopoietic stem cell transplant (HSCT) recipients will develop acute GVHD. The exact risk is dependent on the stem cell source, age of the patient, conditioning, and GVHD prophylaxis used. Given the number of transplants performed, we can expect about 5500 patients/year to develop acute GVHD. Patients can have involvement of three organs: skin (rash/dermatitis), liver (hepatitis/jaundice), and gastrointestinal tract (abdominal pain/diarrhea). One or more organs may be involved. GVHD is a clinical diagnosis that may be supported with appropriate biopsies. The reason to pursue a tissue biopsy is to help differentiate from other diagnoses which may mimic GVHD, such as viral infection (hepatitis, colitis) or drug reaction (causing skin rash). Acute GVHD is staged and graded (grade 0-IV) by the number and extent of organ involvement. Patients with grade III/IV acute GVHD tend to have a poor outcome. Generally the patient is treated by optimizing their immunosuppression and adding methylprednisolone. About 50% of patients will have a solid response to methylprednisolone. If patients progress after 3 days or are not improved after 7 days, they will get salvage (second-line) immunosuppressive therapy for which there is currently no standard-of-care. Well-organized clinical trials are imperative to better define second-line therapies for this disease. Additional management issues are attention to wound infections in skin GVHD and fluid/nutrition management in gastrointestinal GVHD. About 50% of patients with acute GVHD will eventually have manifestations of chronic GVHD.

Absence of Cutaneous TNFα-Producing CD4+ T Cells and TNFα may Allow for Fibrosis Rather than Epithelial Cytotoxicity in Murine Sclerodermatous Graft-Versus-Host Disease, a Model for Human Scleroderma

Graft-versus-host disease (GVHD) is a complication of hematopoietic cell transplantation and is a major source of morbidity and mortality. Two main forms of GVHD occur: cytotoxic GVHD (Cyt GVHD), in which TNFalpha is a critical cytokine in epithelial injury, and sclerodermatous GVHD (Scl GVHD), in which TGFbeta plays a major role in fibrosis. To understand the critical early events in GVHD and scleroderma, we are studying a murine model that uses differences in minor histocompatibility antigens to generate Scl GVHD. We asked the question: what is the immune environment in this model that promotes fibrosis rather than the epithelial injury of Cyt GVHD? We found that in Scl GVHD, cutaneous CD4+ T cells produced IFNgamma and IL-2 but not TNFalpha, also absent by gene array analysis. The role of cutaneous CD4+ T cells in Scl GVHD may not be an active process through production of TGFbeta, but may rather be a passive one due to lack of antigen-presenting cell (APC) support for CD4+ T cells and failure to produce TNFalpha, a potent inhibitor of TGFbeta-induced fibrosis as well as inducer of keratinocyte apoptosis. These APC-T cell interactions and the cytokine environment promote fibrosis rather than cytotoxic epithelial injury in skin in Scl GVHD.

Infliximab for GVHD therapy in children

GVHD remains a significant complication of allogeneic hematopoietic stem cell transplantation. Tumor necrosis factor-alpha (TNF-alpha) is a major mediator of GVHD pathogenesis. Infliximab inhibits the binding of TNF-alpha with its cellular receptors and has been associated with encouraging responses in adults with severe GVHD. We retrospectively evaluated the efficacy and safety of infliximab 10 mg/kg i.v. once a week for a median of eight doses (range 1-162) in 24 children with steroid-resistant GVHD. The overall response rate in 22 evaluable children was 82% (12 CR+6 PR). Among those patients with acute GVHD, both skin and gastrointestinal involvement responded well to infliximab; however long-term outcome was poor. While infliximab may be useful to acutely control GVHD manifestations, GVHD recurs commonly upon discontinuation of infliximab. Within 100 days of the final infliximab dose, 77% of patients had bacterial infections, 32% had viral infections and 13.6% had probable or proven non-candidal invasive fungal infections. Infliximab appears to be well-tolerated and to have activity in steroid-resistant GVHD. Controlled studies to assess the pharmacokinetics and most effective dosing regimen of infliximab for the treatment of GVHD are warranted.

Diagnosis and treatment of transplantation-associated thrombotic microangiopathy: real progress or are we still waiting?

Transplantation-associated thrombotic microangiopathy (TA-TMA) is an infrequent but devastating syndrome that occurs in allogeneic hematopoietic stem cell transplant recipients, and is associated with a variety of transplantation-related factors, including conditioning regimens, immunosuppressive agents, GVHD and opportunistic infections. Progress in managing this condition has been hampered by lack of a consensus definition and poor understanding of the pathophysiology of the disorder. Two different groups recently have proposed consensus definitions, yet they fail to distinguish the primary syndrome from the secondary causes, such as a variety of infections, medication exposure or other conditions. Increasing evidence suggests that TA-TMA is a multifactorial disorder that is distinct from thrombotic thrombocytopenic purpura (TTP), and likely represents the final common pathway of a number of endothelial cell insults. TA-TMA responds poorly to conventional treatment for TTP, including plasma exchange, but newer agents, including daclizumab and defibrotide show promise. In addition, other agents known to modify endothelial responses to injury, including statins, prostacyclin analogues, endothelin-receptor antagonists and free radical scavengers, may lead to improved outcomes for patients affected by this disorder.

Immunobiology of allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) has evolved into an effective adoptive cellular immunotherapy for the treatment of a number of cancers. The immunobiology of allogeneic HSCT is unique in transplantation in that it involves potential immune recognition and attack between both donor and host. Much of the immunobiology of allogeneic HSCT has been gleaned from preclinical models and correlation with clinical observations. We review our current understanding of some of the issues that affect the success of this therapy, including host-versus-graft (HVG) reactions, graft-versus-host disease (GVHD), graft-versus-tumor (GVT) activity, and restoration of functional immunity to prevent transplant-related opportunistic infections. We also review new strategies to optimize the GVT and improve overall immune function while reducing GVHD and graft rejection.

Management of acute graft-versus-host disease

Acute graft-versus-host disease (GvHD) is a frequent complication of allogeneic haemopoietic stem cell transplantation (HSCT) and donor lymphocyte infusions (DLI). Its incidence and severity depends on several factors, such as prophylaxis method, donor/recipient matching, intensity of the conditioning regimen and composition of the graft. Significant progress has been made in recent years in understanding the pathogenesis of the disease, and some of these advances have been translated into clinical trials. First-line treatment of acute GvHD is based on corticosteroids, and produce sustained responses in 50-80% of patients depending on the initial severity. Non-responders are offered second-line therapy, with combinations of immunosuppressive agents, but 1-year survival is 30% in most large trials. New strategies explored include infusion of expanded mesenchymal stem cells (MSC), down regulation of antigen-presenting cells (APC) and suicide gene transduced T cells. Acute GvHD is complicated by severe immunodeficiency causing life-threatening infections. To date, GvHD has not been differentiated from the graft-versus-leukaemia effect. The present review will discuss some of these aspects.

Risk assessment in haematopoietic stem cell transplantation: GvHD prevention and treatment

Graft-versus-host disease (GvHD) is the major cause of transplant-related mortality and morbidity. As it is closely related to the major therapeutic principle, graft-versus-leukaemia (GvL) effect, risk assessment has to balance both risks depending on the pre-transplant status. This is clearly demonstrated when comparing the two major strategies for prevention of GvHD. While the majority of approaches aiming at T-cell depletion show efficacy in reducing acute and chronic GvHD and transplant-related mortality, T-cell depletion also affects graft-versus-leukaemia effects and thus results in a higher relapse rate. Thus, standard prophylaxis relying on calcineurin inhibitors frequently results in at least equivalent or even superior long-term disease-free survival, and the risk of relapse has to be considered when selecting regimens for prevention of GvHD. In addition to this general dilemma, drug-specific side-effects and risks have to be considered when selecting regimens for GvHD prevention and treatment.

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

Allogeneic stem cell transplantation (SCT) remains the definitive immunotherapy for malignancy. However, morbidity and mortality due to graft-vs.-host disease (GVHD) remains the major barrier to its advancement. Emerging experimental data highlights the immuno-modulatory roles of diverse cell populations in GVHD, including regulatory T cells, natural killer (NK) cells, NK T cells, gammadelta T cells, and antigen presenting cells (APC). Knowledge of the pathophysiology of GVHD has driven the investigation of new rational strategies to both prevent severe GVHD and treat steroid-refractory GVHD. Novel cytokine inhibitors, immune-suppressant agents known to preserve or even promote regulatory T-cell function and the depletion of specific alloreactive T-cell sub-populations all promise significant advances in the near future. As our knowledge and therapeutic options expand, the ability to limit GVHD whilst preserving anti-microbial and tumour responses becomes a realistic prospect.

Treatment with biologic therapies and the risk of cancer in patients with IBD

The proven involvement of cytokines in the pathophysiology of IBD has led to the development of powerful, selective, anticytokine drugs--so-called biologics--as a therapy for IBD. Although the efficacy of infliximab, a chimeric monoclonal IgG1 antibody directed against tumor necrosis factor, is proven and the use of biologic agents is growing worldwide, there is concern about their long-term safety, which includes the risk of developing cancer. An increased risk of malignancies, particularly lymphoma, has been reported in some studies of infliximab-treated patients with IBD; however, the increased risk could be caused by the underlying chronic disease, severity of the disease, concomitant medications (e.g. conventional immunomodulators), infliximab itself, or all of these variables. At present, the data do not provide clear evidence for a causal association between infliximab and the increased cancer risk. In appropriately selected patients with severe, refractory Crohn's disease, the benefits of biologic therapy seem to outweigh the cancer risk. Multicenter, case-control studies in large populations, with a long-term follow-up are needed to define the outcome of patients with IBD treated with biologic therapies.

Off-label uses of biologics in dermatology: Rituximab, omalizumab, infliximab, etanercept, adalimumab, efalizumab, and alefacept (Part 2 of 2)

Recently, dermatologists have witnessed a revolution in our therapeutic armamentarium with the development of several novel biologic immunomodulators. Although psoriasis remains the only condition in dermatology for which the use of biologic immunomodulators has been approved by the Food and Drug Administration, these drugs have the potential to significantly impact the treatment of several inflammatory conditions in dermatology. This article includes a review of the mechanism of action, dosing, and side-effect profile, as well as a review of the current literature on off-label uses of the CD20-positive B-cell antagonist rituximab, the IgE antagonist omalizumab, the tumor necrosis factor-alpha antagonists infliximab, etanercept, and adalimumab, and the T-cell response modifiers efalizumab and alefacept.

GVHD—The Nuts and Bolts

Acute graft-versus-host disease (GVHD) is the most frequent, morbid complication following allogeneic hematopoietic stem cell transplantation (HSCT). Its clinical toxicity, requirement for intensive immunosup-pressive management, and associated infections lead to the greatest risks of nonrelapse mortality in HSCT recipients. In acute GVHD, donor-derived T lymphocyte–mediated alloreactivity is complicated by inflammatory responses, cytokine release, direct tissue injury through target cell apoptosis, and secondary tissue injury. The therapeutic management includes effective GVHD prophylaxis to limit the incidence and severity of acute GVHD, prompt and effective therapy if it develops—modified if possible to protect against chronic GVHD—and intensive supportive care relevant to its association with delayed immune reconstitution. As the major ongoing morbid complication following allografting, chronic GVHD is another barrier to patients’ recovery and long-term survival. Recognition of the critical elements in the pathogenesis of GVHD has prompted new approaches to its management and its role in controlling the risks of malignant relapse after allotransplantation. Important elements in the practical management of GVHD will be reviewed.

Recombinant human soluble tumor necrosis factor receptor fusion protein as treatment for steroid refractory graft-versus-host disease following allogeneic hematopoietic stem cell transplantation

Etanercept is a recombinant human soluble tumor necrosis factor (TNF-alpha) receptor fusion protein that inhibits TNF-alpha, a major mediator in the pathogenesis of graft-versus-host disease (GVHD). The purpose of our study was to evaluate the safety and efficacy of etanercept therapy in 21 patients with steroid-refractory acute GVHD (aGVHD) (n = 13) and chronic GVHD (cGVHD) (n = 8). Etanercept 25 mg was given subcutaneously twice weekly for 4 weeks followed by 25 mg weekly for 4 weeks. At the time of initiation of etanercept, 14 patients had skin, 13 had gastro-intestinal, 5 had liver, 5 had pulmonary, and 4 had oral involvement. Twelve patients (57%) completed 12 doses of therapy. Overall, 11 of 21 patients (52%) responded to the treatment with etanercept, including 6 patients (46%) with aGVHD [n = 4 complete response (CR), n = 2 partial response (PR)] and 5 patients (62%) with cGVHD (n = 1 CR, n = 4 PR). Clinical responses were most commonly seen in patients with refractory gut aGVHD with 55% of the patients having a CR and 9% having a PR. CMV reactivation occurred in 48% of patients, bacterial infections in 14% of patients, and fungal infections in 19% of patients. Fourteen patients (67%) were alive after a median follow-up of 429 days (range 71-1007 days) since initiation of etanercept. Seven patients died, 3 of infections, 2 of refractory aGVHD, and 2 of disease progression. In conclusion, our preliminary data indicate that etanercept is well tolerated and can induce a high response rate in patients with steroid-refractory aGVHD and cGVHD, particularly in the setting of GI involvement.

Off-Label Uses of Biologic Agents in Dermatology: A 2006 Update

The introduction of a number of biologic therapies into the market has revolutionized the practice of dermatology. These therapies include adalimumab, alefacept, efalizumab, etanercept, infliximab, IVIg, omalizumab, and rituximab. Most dermatologists are familiar with the indications of these medications that have been approved by the Food and Drug Administration; however, numerous off-label uses have evolved. To update the reader on more recent uses of the biologics for off-label dermatologic use, this article will emphasize more recent published data from 2005 through the date of submission in May 2006.

A phase 2/3 multicenter randomized clinical trial of ABX-CBL versus ATG as secondary therapy for steroid-resistant acute graft-versus-host disease

Treatment for steroid-resistant acute graft-versus-host disease (GVHD) has had limited success. ABX-CBL is a hybridoma-generated murine IgM monoclonal antibody against the CD147 antigen, weakly expressed on human leukocytes and up-regulated on activated lymphocytes. A prospective, multicenter, open-label, randomized clinical trial comparing ABX-CBL to antithymocyte globulin (ATG) for treatment of steroid-resistant acute GVHD was conducted in 95 patients at 21 centers. Forty-eight patients received ABX-CBL daily for 14 consecutive days followed by up to 6 weeks of ABX-CBL twice weekly. Forty-seven patients received equine ATG, 30 mg/kg every other day for a total of 6 doses with additional courses as needed. By day 180, overall improvement was similar in the patients receiving ABX-CBL and in those receiving ATG (56% versus 57%, P = .91). Patient survival at 18 months was less favorable on ABX-CBL than on ATG (35% versus 45%), with the 95% confidence interval ruling out that ABX-CBL provides at least a 10.4% improvement. Data from this trial suggest that ABX-CBL does not offer an improvement over ATG in the treatment of acute steroid-resistant GVHD. This prospective, multicenter, randomized clinical trial for steroid-resistant acute GVHD serves as a model for future evaluation of new agents.

Mesenchymal stem cells for treatment of therapy-resistant graft-versus-host disease

BACKGROUND

Mesenchymal stem cells (MSC) have immunomodulatory effects. The aim was to study the effect of MSC infusion on graft-versus-host disease (GVHD).

METHODS

We gave MSC to eight patients with steroid-refractory grades III-IV GVHD and one who had extensive chronic GVHD. The MSC dose was median 1.0 (range 0.7 to 9)x10(6)/kg. No acute side-effects occurred after the MSC infusions. Six patients were treated once and three patients twice. Two patients received MSC from HLA-identical siblings, six from haplo-identical family donors and four from unrelated mismatched donors.

RESULTS

Acute GVHD disappeared completely in six of eight patients. One of these developed cytomegalovirus gastroenteritis. Complete resolution was seen in gut (6), liver (1) and skin (1). Two died soon after MSC treatment with no obvious response. One of them had MSC donor DNA in the colon and a lymph node. Five patients are still alive between 2 months and 3 years after the transplantation. Their survival rate was significantly better than that of 16 patients with steroid-resistant biopsy-proven gastrointestinal GVHD, not treated with MSC during the same period (P = 0.03). One patient treated for extensive chronic GVHD showed a transient response in the liver, but not in the skin and he died of Epstein-Barr virus lymphoma.

CONCLUSION

MSC is a very promising treatment for severe steroid-resistant acute GVHD.

Treatment Costs and Survival in Patients with Grades III-IV Acute Graft-Versus-Host Disease after Allogenic Hematopoietic Stem Cell Transplantation During Three Decades

To determine development of treatment, costs, and survival for patients with grades III/IV acute graft-versus-host disease (GVHD), data from 88 patients with grades III/IV acute GVHD were collected. The patients were divided into three groups: patients who received transplants from 1977 through 1989 (group A), 1990 through 1999 (group B), and 2000 through 2004 (group C). The costs for treatment, enumerated to year 2003 costs, were calculated. An increased 1-year survival rate was found in group C, at 21% versus 9% and 8% for groups A and B, respectively (P=0.02). Death by acute GVHD was increased by repeat transplantation (P<0.001), grade IV acute GVHD (P<0.001), human leukocyte antigen mismatch (P=0.009), and transplantation before 2000 (P=0.015). Transplantation after 1990 (P=0.003) and grade IV acute GVHD (P=0.03) were associated with higher treatment costs. It was found that the time the patients had GVHD did not differ among the three groups. In conclusion, the costs and survival rates associated with severe acute GVHD has increased in recent years.

Biologics in the prevention and treatment of graft rejection

Biologics are used in solid organ allografting and hematopoietic stem cell transplantation (HSCT) for the induction and maintenance of immunosuppression. In solid organ transplantation, antibodies targeting T cells are part of induction protocols administered for initiation of immunosuppression during organ transfer and during sustained post transplant periods for prevention of graft rejection. Several clinical trials in renal allografting provide data for the efficacy and safety of biologics in this clinical setting. Application of biologics also allows the reduction of calcineurin inhibitors, thereby reducing toxicity and improving long-term graft function. In acute rejection periods, anti T cell antibodies are established in steroid-resistant cases. Strategies interfering with the activity of soluble cytokines are less frequently applied for solid organ transplantation. In HSCT, T cell directed antibodies as part of conditioning protocols improve engraftment and reduce the incidence of detrimental graft vs host disease (GvHD). In acute GvHD, both antibodies targeting T cells and cytokines like TNF-alpha are established therapeutics for remission induction.

Combination antithymocyte globulin and soluble TNFalpha inhibitor (etanercept) +/- mycophenolate mofetil for treatment of steroid refractory acute graft-versus-host disease

Antitumor necrosis factor-alpha antibodies are increasingly being used for the treatment of steroid-refractory acute graft-versus-host disease (GVHD) complicating allogeneic stem cell transplantation. We retrospectively reviewed the outcomes of 16 patients with refractory acute predominantly visceral GVHD treated with combination antithymocyte globulin (ATG), tacrolimus and etanercept +/- mycophenolate mofetil (MMF) at our institution. Overall response rate (CR+PR) was 81%, with median survival post commencing salvage immunosuppression 224 days (range 20-1216 days). In total, eight patients (50%) died, including from progressive GVHD in two cases (13%), infection in five (31%) and relapse of underlying malignancy in one (6%). In comparison to our previous experience of ATG+tacrolimus as treatment for refractory visceral GVHD, both response rate and overall survival were improved with addition of etanercept, with no apparent increase in infectious complications. As such, use of etanercept in combination with ATG +/- MMF for treatment of steroid refractory acute GVHD appears to be associated with high response rates, significant survival and no unexpected toxicity. Further study of this immunosuppression combination in a larger cohort of patients in this setting is indicated.

Therapy for severe refractory acute graft-versus-host disease with basiliximab, a selective interleukin-2 receptor antagonist

Basiliximab is a chimeric monoclonal antibody that binds to the alpha chain of IL-2R on activated cytotoxic T-cells, inhibiting lymphocyte proliferation. We report 34 patients with refractory acute GVHD (grade III-IV) who received basiliximab from December 1998 to October 2003. Adults received 40 mg weekly (2-3 doses) and children received half of this dose. Median age was 13 years. Twenty-five donors were unrelated. The stem cell source was bone marrow in 30 and cord blood in four. Complete responses were seen in 27/32 patients (84%) with skin, 12/25 (48%) with gut and 6/23 (26%) with liver GVHD. Median duration of response was 38 days (5-1103). Overall survival at 5 years was 20%. Eleven patients (32%) are alive. The main causes of death were CMV (n=4), fungus (n=6), sepsis (n=8), hemorrhage (n=2), and relapse (n=2). Graft-versus-host disease flares were observed in 14 patients (41%), half being rescued by other therapies. In conclusion, basiliximab was able to induce complete responses in patients with refractory acute GVHD. Prospective studies are necessary to evaluate the optimal treatment schedule.

Therapeutic potential of cytokine and chemokine antagonists in cancer therapy

A new paradigm is becoming widely accepted, that chronic inflammation, driven in part by chemokines and cytokines at the site of a tumour, may facilitate tumour progression instead of promoting anti-tumour immunity. Tumours and activated stromal cells secrete pro-inflammatory chemokines and cytokines that act either directly or indirectly through stimulation of the vascular endothelium to recruit leukocytes to the tumour. After activation, these tumour-associated leukocytes release angiogenic factors, mitogens, proteolytic enzymes, and chemotactic factors, recruiting more inflammatory cells and stimulating angiogenesis to sustain tumour growth and facilitate tumour metastasis. Breaking this cycle by inhibiting targets such as cytokines, chemokines and other inflammatory mediators, either alone, or more realistically, in combination with other therapies, such as anti-angiogenic or cytotoxic agents, may provide highly efficacious therapeutic regimens for the treatment of malignancies. This article reviews anti-cytokine and anti-chemokine therapies being pursued in cancer, and discusses in more detail anti-tumour necrosis factor-alpha (TNF) approaches.

Shared biology of GVHD and GVT effects: Potential methods of separation

The difficult separation of clinical graft-versus-tumor (GVT) effects from graft-versus-host disease (GVHD) reflects their shared biology. Experimental approaches to mediate GVT effects while limiting GVHD include: (1) allograft T cell depletion followed by immune enhancement; (2) modulation of T cell dose or T cell subset composition; (3) donor lymphocyte infusion; (4) reduced-intensity host preparation; (5) modulation of Th1/Th2 and Tc1/Tc2 cell balance; (6) cytokine therapy or neutralization; (7) T regulatory cell therapy; (8) co-stimulatory pathway modulation; (9) chemokine pathway modulation; (10) induction of antigen-specific T cells; (11) alloreactive NK cell therapy; and (12) targeted pharmaceutical inhibition of proteosome, mammalian target of rapamycin, and histone deacetylase pathways. Clearly, a multitude of approaches exist that hold promise for separating GVT effects from GVHD. Future success in this endeavor will require a strong commitment towards translational research and continued advances in cell, vaccine, cytokine, monoclonal antibody, and targeted molecular therapy.

Capsule endoscopy as a diagnostic tool in the evaluation of graft-vs.-host disease

Capsule endoscopy is a relatively new technology that has allowed gastroenterologists to visualize the mucosa of the small intestine. This technology is playing an expanding role in both adult and pediatric gastroenterology. In this report, we present an 8-yr-old child following allogeneic hematopoietic cell transplantation who developed large volume bloody diarrhea requiring multiple packed red blood cell transfusions that was resistant to aggressive therapy for GVHD. The capsule endoscopy performed on this patient provided significant information not provided by upper endoscopy and colonoscopy that allowed for successful treatment changes. This case demonstrates that capsule endoscopy is a diagnostic tool that may play an important role in the assessment of patients, including children, with possible GVHD.

Approaches to graft-vs-host disease

Graft-vs-host disease (GVHD) is one of the most difficult problems in stem cell transplantation. It is best considered in the context of the normal immune response. The role of the immune system is to identify and eliminate foreign antigens. In the case of GVHD, the antigens are minor histocompatibility antigens (mHA) recognized in an inflammatory milieu. The immune system cannot reasonably be expected to selectively recognize microbial antigens and ignore mHA. This approach would require the generation of selective tolerance--something that clearly occurs but which we have frustratingly little control over. While we can often treat and remit even life-threatening GVHD, the consequence has been the development of fatal opportunistic infections. The challenge is to change our style of thinking about GVHD to allow a transition from a 'nuclear winter' approach that controls GVHD at the price of infection, to a more selective patient approach that recognizes the limitations of immunosuppressive therapy.

Pilot trial on the use of etanercept and methylprednisolone as primary treatment for acute graft-versus-host disease

Clinical and preclinical data indicate that tumor necrosis factor (TNF)-alpha is an important mediator of acute graft-versus-host disease (aGVHD) after allogeneic bone marrow transplantation. We completed a study using etanercept, a fusion protein capable of neutralizing TNF-alpha, for the initial treatment of aGVHD. Etanercept (25 mg subcutaneously) was administered twice weekly for 16 doses, along with methylprednisolone (2 mg/kg) and tacrolimus for biopsy-proven aGVHD. Twenty patients with a median age of 47 years (range, 8-63 years) were enrolled. Fourteen patients with grade II aGVHD (11 family donors and 3 unrelated donors) and 6 patients with grade III aGVHD (3 family donors and 3 unrelated donors) were treated. Twelve patients completed 16 doses of therapy, and 8 received 5 to 15 doses. Reasons for not completing all doses of etanercept included progression of aGVHD (n = 4), relapsed leukemia (n = 2), progression of pulmonary and central nervous system lesions (n = 1), and perforated duodenal ulcer (n = 1). Fifteen (75%) of 20 patients had complete resolution of aGVHD within 4 weeks of therapy. Increasing levels of soluble TNF receptor 1 plasma concentration during the first 4 weeks of therapy indicated progression of aGVHD in 5 patients. In contrast, for 15 responding patients, soluble TNF receptor 1 plasma concentration levels returned to baseline. These data demonstrate the feasibility of using cytokine blockade in the early treatment of aGVHD.

New findings and key questions in hematopoietic stem cell transplantation

Invasive aspergillosis remains the primary cause of death from infection following allogeneic stem cell transplantation. Most cases occur during the second or third month after transplantation, during graft-versus-host disease or immunosuppression. Strategies for management of these cases include the development of more effective antifungals for prophylaxis, the use of biological markers to improve the early diagnosis of aspergillosis, new approaches to transplantation to reduce the risk of infection, and the emerging area of targeted cellular therapy.

Denileukin diftitox for the treatment of steroid-resistant acute graft-versus-host disease

Acute graft-versus-host disease (aGVHD) is partly mediated through activated T cells, and these cells are known to express the high-affinity receptor for interleukin 2 (IL-2R). Denileukin diftitox is composed of human IL-2 and diphtheria toxin that is cytotoxic to activated lymphocytes expressing the high-affinity IL-2R. We describe the results of a phase II study of denileukin diftitox in 22 patients with steroid-resistant aGVHD. Twenty patients were treated at dose level 1 (4.5 microg/kg daily on days 1-5 and then weekly on study days 8, 15, 22, and 29), and 2 patients were treated at dose level 2 (9.0 microg/kg delivered on the same schedule). Dose level 2 was associated with grade 3/4 renal and hepatic toxicity and vascular leak syndrome, and no further patients were treated at this level. Dose level 1 was generally well tolerated. The response of aGVHD was assessed at study days 36 and 100. Nine patients (41%) responded, all with a complete response at study day 36, and 6 patients (27%) responded at study day 100 (4 complete responses and 2 partial responses). Denileukin diftitox has promising activity in steroid-resistant aGVHD, and further study is warranted.

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.

Successful treatment of bronchiolitis obliterans in a bone marrow transplant patient with tumor necrosis factor-alpha blockade

Bronchiolitis obliterans (BO) in children is a rare, inflammatory/fibrosing process involving the small airways that often results in progressive, irreversible obstructive pulmonary disease. Because treatment has focused mainly on supportive care and generally unsuccessful immunosuppression, children with BO experience significant morbidity and mortality. We report a case of biopsy-proven BO after bone marrow transplantation in a child who, after failed corticosteroid therapy, was treated with infliximab, a monoclonal antibody with binding specificity for human tumor necrosis factor-alpha. With initiation of treatment, her pulmonary symptoms and radiographic and spirometric evidence of BO resolved. Nine months later, she remains asymptomatic and shows no evidence of pulmonary decompensation. This case illustrates a successful treatment of BO with selective tumor necrosis factor-alpha blockade.

Increased Levels of Tumor Necrosis Factor α Are Associated with an Increased Risk of Cytomegalovirus Infection after Allogeneic Hematopoietic Stem Cell Transplantation

Tumor necrosis factor-alpha (TNF) has been implicated in the reactivation of cytomegalovirus (CMV) at a cellular level. We therefore hypothesized that increased posttransplantation TNF levels may be associated with the development of CMV antigenemia (CMV-Ag). We studied 134 patients undergoing allogeneic hematopoietic stem cell transplantation. After excluding CMV-negative donor and recipient pairs, 94 patients were evaluable. By cluster analysis, 2 groups were designated by TNF levels obtained between days 4 and 7 after transplantation: 58 patients had low levels (median, 0 pg/mL; range, 0-5.5 pg/mL), and 36 patients had high levels (median, 43.75 pg/mL; range, 7.5-1756 pg/mL). To determine the independent effect of TNF on the development of CMV-Ag and acute graft-versus-host disease and on survival, Kaplan-Meier and Cox models stratified by TNF patient groups were evaluated. High TNF levels were associated with a more rapid onset of CMV-Ag (P < .001) and with the occurrence of the composite end point of CMV-Ag or death (P < .001). Factors independently associated with CMV-Ag in multivariate analysis were a high TNF level (hazard ratio [HR], 2.57; P = .003) and acute graft-versus-host disease (as a time-dependent covariate; HR, 2.30; P = .010). Factors independently associated with the composite end point of CNV-Ag or death were a high TNF level (HR, 2.42; P < .001) and patient age (per year; HR, 1.93; P = .017). In conclusion, a high posttransplantation TNF level is significantly associated with the risk for developing CMV infection. Early detection of high levels of TNF may be used to identify patients at high risk for developing CMV-Ag.

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.

Treatment of Gastrointestinal Acute Graft-Versus-Host Disease

Therapy of acute graft-versus-host disease (GVHD) aims to selectively alter the graft- host interactions to foster antitumor effect and minimize antihost effects. The immunosuppression produced by the various therapies ranges from broad, nonselective effects to relatively narrow targeted impact. Despite advances in understanding the pathophysiology of GVHD, newer agents with more selective effects have not yet produced therapeutic advances. The newer targeted agents continue to produce a degree of immunosuppression in which infection and relapse of malignancy are all too common. High-dose systemic steroids remain, as they have for two decades, the initial treatment of choice. Patients failing to respond to steroids continue to represent a challenge, as no second-line therapy is clearly superior to the others. However, some of the new agents appear to be particularly effective in certain organs involved with acute GVHD. For those patients with steroid-refractory GVHD involving primarily the gut, we favor infliximab with concomitant antifungal therapy. For those with primarily skin or liver disease, we favor extracorporeal photochemotherapy.

Novel strategies for steroid-refractory acute graft-versus-host disease

PURPOSE OF REVIEW

Graft-versus-host disease is one of the commonest complications of allogeneic bone marrow or peripheral blood stem cell transplantation. This review will cover advances in the pathophysiology of graft-versus-host disease and new agents under investigation for the treatment of this disorder. Patients developing graft-versus-host disease who fail to respond to steroids have a poor prognosis. In this group of people, morbidity and mortality are very high.

RECENT FINDINGS

Novel agents are currently under investigation for the treatment of such devastating disorders. Pentostatin, denileukin diftitox, mycophenolate mofetil, extracorporeal photopheresis, and several monoclonal antibodies have been used, some of them with encouraging results.

SUMMARY

As supportive care improves and new agents are added to the armamentarium against steroid-refractory acute graft-versus-host disease, the prognosis of this entity may start to change. Patients with this complication after transplantation should be enrolled, whenever possible, in clinical trials to find effective therapies.

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.

The changing face of invasive fungal infections in hematopoietic cell transplant recipients

PURPOSE OF REVIEW

To review recent observations that describe changes in the likelihood of invasive fungal infections, shifts in types of fungal pathogens, and altered manifestations of fungal syndromes after hematopoietic cell transplantation and explore how changes in transplant practices are influencing these epidemiologic shifts.

RECENT FINDINGS

Shifts in invasive fungal infections are occurring as a consequence of changes in transplant practices, including the intensity of conditioning regimens, new immunosuppressive therapies, new antineoplastic therapies administered before hematopoietic cell transplantation, and possibly use of mold-active agents as prophylaxis. Non-fumigatus Aspergillus species and other mold pathogens, such as Fusarium and zygomycosis, are assuming greater prominence and may be increasing.

SUMMARY

Epidemiologic shifts in invasive fungal infections are likely co-travelers with advances in transplant practices. Thus, ongoing studies of epidemiologic shifts in invasive fungal infections are important.

The safety of interferon-?-1b therapy for invasive fungal infections after hematopoietic stem cell transplantation

BACKGROUND

The restoration of normal immune responses, especially of the T-helper type 1 immune response, is an important predictor of fungal infection outcome in patients with malignant disease who undergo hematopoietic stem cell transplantation (HSCT). The authors sought to evaluate the safety of adjuvant recombinant interferon-gamma-1b as an immune-modulatory therapy HSCT recipients.

METHODS

Thirty-two patients received interferon-gamma-1b after undergoing HSCT at the author's institution between 1998 and 2003. A retrospective analysis was undertaken after obtaining permission from the Institutional Review Board.

RESULTS

Twenty-six of 32 patients (81%) received allogeneic stem cell grafts. All but 1 patient received interferon-gamma-1b and antifungals to treat infections; the other patients received interferon-gamma-1b to promote autologous graft-versus-tumor effect. Interferon-gamma-1b usually was administered at a dose of 50 mug subcutaneously every other day. The median duration (+/- standard deviation) of interferon-gamma-1b therapy was 6+/-6.5 doses (range, 1-29 doses), and the median cumulative dose was 487+/-453 mug (range, 35-2175 microg). During therapy with interferon-gamma-1b, fever was common (n=9 patients; 28%). In 1 patient (3%), new-onset lymphocytopenia occurred but resolved after cytokine therapy was discontinued; there were no interferon- gamma-1b-related episodes of neutropenia, thrombocytopenia, anemia, or liver dysfunction. Interferon-gamma-1b therapy did not precipitate or exacerbate acute or chronic graft-versus-host disease (GVHD). In fact, in 2 of 7 patients (29%) with acute GVHD and in 3 of 10 patients (30%) with chronic GVHD, significant improvements in GVHD were noted during therapy with interferon-gamma-1b. Among the 26 patients with aspergillosis, 14 patients (54%) died. However, 5 of 10 patients (50%) with presumed pulmonary aspergillosis, 3 of 9 patients (33%) with probable pulmonary aspergillosis, 1 of 2 patients (50%) with definite pulmonary aspergillosis, and 3 of 5 patients (60%) with disseminated aspergillosis responded to antifungals and adjuvant interferon-gamma-1b.

CONCLUSIONS

Recombinant interferon-gamma-1b was tolerated without serious adverse reactions in HSCT recipients. A large, prospective, randomized study will be needed to evaluate the efficacy of this cytokine in high-risk HSCT recipients who have invasive mycoses.

Graft-versus-host disease: How to translate new insights into new therapeutic strategies

Graft-versus-host disease occurs when transplanted donor-derived T lymphocytes recognize major or minor histocompatibility complex proteins and their associated peptides expressed by recipient antigen-presenting cells. A widely accepted paradigm for the pathophysiology of acute GVHD is based on the existence of 3 sequential steps: (1) injury to the host environment (as would occur during conditioning regimens); (2) donor T-cell activation, proliferation, and differentiation; and (3) damage to the target tissue caused by either cytotoxicity or indirectly by inflammatory cytokines. In order to reduce the incidence of GVHD, recent studies have focused on methods of prophylaxis as well as novel treatments for established GVHD. We review each phase in the development of acute GVHD and discuss recently developed interventions aimed to prevent or treat GVHD by interfering with these pathways.