Clinical use of anti-TNF therapy and increased risk of infections

Pathogenic Inflammation and Its Therapeutic Targeting in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE, lupus) is a highly complex and heterogeneous autoimmune disease that most often afflicts women in their child-bearing years. It is characterized by circulating self-reactive antibodies that deposit in tissues, including skin, kidneys, and brain, and the ensuing inflammatory response can lead to irreparable tissue damage. Over many years, clinical trials in SLE have focused on agents that control B- and T-lymphocyte activation, and, with the single exception of an agent known as belimumab which targets the B-cell survival factor BAFF, they have been disappointing. At present, standard therapy for SLE with mild disease is the agent hydroxychloroquine. During disease flares, steroids are often used, while the more severe manifestations with major organ involvement warrant potent, broad-spectrum immunosuppression with cyclophosphamide or mycophenolate. Current treatments have severe and dose-limiting toxicities and thus a more specific therapy targeting a causative factor or signaling pathway would be greatly beneficial in SLE treatment. Moreover, the ability to control inflammation alongside B-cell activation may be a superior approach for disease control. There has been a recent focus on the innate immune system and associated inflammation, which has uncovered key players in driving the pathogenesis of SLE. Delineating some of these intricate inflammatory mechanisms has been possible with studies using spontaneous mouse mutants and genetically engineered mice. These strains, to varying degrees, exhibit hallmarks of the human disease and therefore have been utilized to model human SLE and to test new drugs. Developing a better understanding of the initiation and perpetuation of disease in SLE may uncover suitable novel targets for therapeutic intervention. Here, we discuss the involvement of inflammation in SLE disease pathogenesis, with a focus on several key proinflammatory cytokines and myeloid growth factors, and review the known outcomes or the potential for targeting these factors in SLE.

Listeria monocytogenes Meningitis in an Immunosuppressed Patient with Autoimmune Hepatitis and IgG4 Subclass Deficiency

A 51-year-old Caucasian woman with Listeria monocytogenes meningitis was treated and discharged after an uncomplicated course. Her medical history included immunosuppressive treatment with prednisolone and azathioprine for autoimmune hepatitis. A diagnostic work-up after the meningitis episode revealed that she had low levels of the IgG4 subclass. To our knowledge, this is the first case report describing a possible association between autoimmune hepatitis and the occurrence of Listeria monocytogenes meningitis, describing a possible association between Listeria monocytogenes meningitis and deficiency of the IgG4 subclass and finally describing a possible association between Listeria monocytogenes meningitis and immunosuppressive therapy with prednisolone and azathioprine.

In vivo effect of anti-TNF agent (etanercept) in reactivation of latent toxoplasmosis

Toxoplasma gondii (T. gondii), an intracellular parasite, establishes a chronic infection by forming cysts preferentially in the brain. TNF-α plays an important role in controlling the infection caused by this protozoan. Thus, the blockade of TNF-α could cause reactivation of latent toxoplasmosis infection as well as increase the risk of acute toxoplasmosis. This study evaluated the effect of etanercept, a TNF-α antagonist in reactivation of latent toxoplasmosis compared to the therapeutic effect of sulfadiazine and pyrimethamine in combination on the progress of the disease. A total of 40 laboratory-bred Swiss albino mice were infected with Me49 strain of T. gondii and divided into four groups: infected control group; treated group with sulfadiazine and pyrimethamine; treated group with etanercept and treated group with both etanercept and sulfadiazine and pyrimethamine. The mean number and size of tissue cysts in brain smears of mice of each group were determined and also, serum levels of TNF-α were assessed in different study groups by an enzyme linked immunosorbent assay. The results showed that the mean TNF-α level was significantly different in the treated groups compared to that in infected control group. The highest level of TNF-α was found in the infected controls. After treatment with etanercept alone or combined with sulfadiazine and pyrimethamine, it was significantly decreased. In this study, reactivation of latent toxoplasmosis was observed by a significant increase in the mean number and sizes of Toxoplasma tissue cysts in brains of mice with established chronic toxoplasmosis after treatment with etanercept alone or combined with conventional treatment compared to both untreated chronically infected controls and infected mice treated with sulfadiazine and pyrimethamine. It was concluded that etanercept, a TNF-α antagonist may play a role in reactivation of latent toxoplasmosis. So, serological screening for toxoplasmosis might offer a valuable aid for patients treated with this drug.

RP105 Engages Phosphatidylinositol 3-Kinase p110δ To Facilitate the Trafficking and Secretion of Cytokines in Macrophages during Mycobacterial Infection

Cytokines are key regulators of adequate immune responses to infection with Mycobacterium tuberculosis. We demonstrate that the p110δ catalytic subunit of PI3K acts as a downstream effector of the TLR family member RP105 (CD180) in promoting mycobacteria-induced cytokine production by macrophages. Our data show that the significantly reduced release of TNF and IL-6 by RP105(-/-) macrophages during mycobacterial infection was not accompanied by diminished mRNA or protein expression. Mycobacteria induced comparable activation of NF-κB and p38 MAPK signaling in wild-type (WT) and RP105(-/-) macrophages. In contrast, mycobacteria-induced phosphorylation of Akt was abrogated in RP105(-/-) macrophages. The p110δ-specific inhibitor, Cal-101, and small interfering RNA-mediated knockdown of p110δ diminished mycobacteria-induced TNF secretion by WT but not RP105(-/-) macrophages. Such interference with p110δ activity led to reduced surface-expressed TNF in WT but not RP105(-/-) macrophages, while leaving TNF mRNA and protein expression unaffected. Activity of Bruton's tyrosine kinase was required for RP105-mediated activation of Akt phosphorylation and TNF release by mycobacteria-infected macrophages. These data unveil a novel innate immune signaling axis that orchestrates key cytokine responses of macrophages and provide molecular insight into the functions of RP105 as an innate immune receptor for mycobacteria.

Regulation of tumour necrosis factor signalling: live or let die

Tumour necrosis factor (TNF) is a pro-inflammatory cytokine that has important roles in mammalian immunity and cellular homeostasis. Deregulation of TNF receptor (TNFR) signalling is associated with many inflammatory disorders, including various types of arthritis and inflammatory bowel disease, and targeting TNF has been an effective therapeutic strategy in these diseases. This Review focuses on the recent advances that have been made in understanding TNFR signalling and the consequences of its deregulation for cellular survival, apoptosis and regulated necrosis. We discuss how TNF-induced survival signals are distinguished from those that lead to cell death. Finally, we provide a brief overview of the role of TNF in inflammatory and autoimmune diseases, and we discuss up-to-date and future treatment strategies for these disorders.

Infliximab Does Not Worsen Outcomes During Flare-ups Associated with Cytomegalovirus Infection in Patients with Ulcerative Colitis

BACKGROUND

Immunosuppressive therapies used for treating ulcerative colitis are known to favor chronic and latent viral diseases. This study aimed at evaluating prospectively the association between colonic cytomegalovirus (CMV) reactivation and anti-tumor necrosis factor (TNF) monoclonal antibodies (mabs) by comparison to azathioprine (AZA) in a series of flare-ups occurring in consecutive ulcerative colitis patients.

METHODS

A total of 109 flare-ups were recorded in 73 patients receiving a maintenance therapy by anti-TNF mabs (n = 69) or AZA (n = 40). The CMV DNA load in colonic tissue was determined by reverse transcription polymerase chain reaction on a pair of biopsies.

RESULTS

The number of CMV reactivation was of 35% and 38% in patients receiving anti-TNF mabs and AZA, respectively. The median of CMV DNA load was 378 [10-29,800] and 8300 [10-3,25,000] copies/mg of tissue in patients treated by anti-TNF mabs and AZA, respectively (P = 0.11 by Mann-Whitney U test). In a subgroup of 45 patients under anti-TNF mabs requiring an optimized treatment by infliximab, clinical remission (partial Mayo score <3) was not significantly impacted by the presence of CMV reactivation at the time of flare-up (P = 0.52). Twenty of these patients underwent a second colonic biopsy 8 weeks after the initiation of flare-up therapy; except for 3 patients, the colonic CMV DNA load was stable or decreased.

CONCLUSIONS

Patients under anti-TNF maintenance therapy are not at higher risk of CMV reactivation in case of flare-up. No reciprocal adverse influence was observed between anti-TNF mabs and CMV infection, suggesting that these drugs must be considered for treating flare-ups associated to CMV reactivation.

Selective Allosteric Inhibition of MMP9 Is Efficacious in Preclinical Models of Ulcerative Colitis and Colorectal Cancer

Expression of matrix metalloproteinase 9 (MMP9) is elevated in a variety of inflammatory and oncology indications, including ulcerative colitis and colorectal cancer. MMP9 is a downstream effector and an upstream mediator of pathways involved in growth and inflammation, and has long been viewed as a promising therapeutic target. However, previous efforts to target matrix metalloproteinases (MMPs), including MMP9, have utilized broad-spectrum or semi-selective inhibitors. While some of these drugs showed signs of efficacy in patients, all MMP-targeted inhibitors have been hampered by dose-limiting toxicity or insufficient clinical benefit, likely due to their lack of specificity. Here, we show that selective inhibition of MMP9 did not induce musculoskeletal syndrome (a characteristic toxicity of pan-MMP inhibitors) in a rat model, but did reduce disease severity in a dextran sodium sulfate-induced mouse model of ulcerative colitis. We also found that MMP9 inhibition decreased tumor growth and metastases incidence in a surgical orthotopic xenograft model of colorectal carcinoma, and that inhibition of either tumor- or stroma-derived MMP9 was sufficient to reduce primary tumor growth. Collectively, these data suggest that selective MMP9 inhibition is a promising therapeutic strategy for treatment of inflammatory and oncology indications in which MMP9 is upregulated and is associated with disease pathology, such as ulcerative colitis and colorectal cancer. In addition, we report the development of a potent and highly selective allosteric MMP9 inhibitor, the humanized monoclonal antibody GS-5745, which can be used to evaluate the therapeutic potential of MMP9 inhibition in patients.

The effect of Indomethacin and Betamethasone on the cytokine response of human neonatal mononuclear cells to gram-positive bacteria

Intrauterine infections with gram-positive bacteria pose a serious threat to neonates since they can result in neonatal sepsis, induce a fetal inflammatory response and also cause preterm birth. Despite intensive care, prematurity remains a leading cause of neonatal death, and is often accompanied by a number of morbidities. In order to prevent premature birth, tocolytic agents like Indomethacin are administered. Betamethasone is used to promote lung maturation and prevent respiratory distress syndrome. A combination of both drugs is assumed to prevent premature delivery while simultaneously facilitating lung maturation. This study investigates the effect of Betamethasone, Indomethacin and a combination of both on the cytokine production of neonatal cord blood mononuclear cells (CBMC) after stimulation with lysates of the gram-positive pathogens Streptococcus agalactiae and Enterococcus faecalis. The aim of the study is to determine the impact of these drugs on the function of the neonatal immune system which should aid clinicians in choosing the optimal therapy in case of preterm birth associated with intrauterine infection. Betamethasone reduced the production of the pro-inflammatory cytokines IL-6, IL-12p40, MIP-1α and TNF and increased the expression of the anti-inflammatory cytokine IL-10, depending on the pathogen used for stimulation. In contrast to Betamethasone, Indomethacin almost exclusively increased IL-10 production. The combination of both drugs decreased the expression of IL-6, IL-12p40, MIP-1α and TNF while increasing IL-10 production, depending on the concentration of Indomethacin and the pathogen used for stimulation. Based on our results, the combination therapy with Indomethacin and Betamethasone has a similar effect on cytokine production as Betamethasone alone, which is generally administered in case of impending preterm birth. However, the combination therapy has the advantage of promoting lung maturation while simultaneously blocking preterm labor effectively.

Tumor necrosis factor, tumor necrosis factor inhibition, and cancer risk

OBJECTIVE

Tumor necrosis factor (TNF) is a highly pleiotropic cytokine with multiple activities other than its originally discovered role of tumor necrosis in rodents. TNF is now understood to play a contextual role in driving either tumor elimination or promotion. Using both animal and human data, this review examines the role of TNF in cancer development and the effect of TNF and TNF inhibitors (TNFis) on malignancy risk.

RESEARCH DESIGN

A literature review was performed using relevant search terms for TNF and malignancy.

RESULTS

Although administration of TNF can cause tumor regression in specific rodent tumor models, human expression polymorphisms suggest that TNF can be a tumor-promoting cytokine, whereas blocking the TNF pathway in a variety of tumor models inhibits tumor growth. In addition to direct effects of TNF on tumors, TNF can variously affect immunity and the tumor microenvironment. Whereas TNF can promote immune surveillance designed to eliminate tumors, it can also drive chronic inflammation, autoimmunity, angiogenesis, and other processes that promote tumor initiation, growth, and spread. Key players in TNF signaling that shape this response include NF-κB and JNK, and malignant-inflammatory cell interactions, each of which may have different responses to TNF signaling. Focusing on rheumatoid arthritis (RA) patients, where clinical experience is most extensive, a review of the clinical literature shows no increased risk of overall malignancy or solid tumors such as breast and lung cancers with exposure to TNFis. Lymphoma rates are not increased with use of TNFis. Conflicting data exist regarding the risks of melanoma and nonmelanoma skin cancer. Data regarding the risk of recurrent malignancy are limited.

CONCLUSIONS

Overall, the available data indicate that elevated TNF is a risk factor for cancer, whereas its inhibition in RA patients is not generally associated with an increased cancer risk. In particular, TNF inhibition is not associated with cancers linked to immune suppression. A better understanding of the tumor microenvironment, molecular events underlying specific tumors, and epidemiologic studies of malignancies within specific disease indications should enable more focused pharmacovigilance studies and a better understanding of the potential risks of TNFis.

Targeted localized use of therapeutic antibodies: a review of non-systemic, topical and oral applications

Therapeutic antibodies provide important tools in the "medicine chest" of today's clinician for the treatment of a range of disorders. Typically monoclonal or polyclonal antibodies are administered in large doses, either directly or indirectly into the circulation, via a systemic route which is well suited for disseminated ailments. Diseases confined within a specific localized tissue, however, may be treated more effectively and at reduced cost by a delivery system which targets directly the affected area. To explore the advantages of the local administration of antibodies, we reviewed current alternative, non-systemic delivery approaches which are in clinical use, being trialed or developed. These less conventional approaches comprise: (a) local injections, (b) topical and (c) peroral administration routes. Local delivery includes intra-ocular injections into the vitreal humor (i.e. Ranibizumab for age-related macular degeneration), subconjunctival injections (e.g. Bevacizumab for corneal neovascularization), intra-articular joint injections (i.e. anti-TNF alpha antibody for persistent inflammatory monoarthritis) and intratumoral or peritumoral injections (e.g. Ipilimumab for cancer). A range of other strategies, such as the local use of antibacterial antibodies, are also presented. Local injections of antibodies utilize doses which range from 1/10th to 1/100th of the required systemic dose therefore reducing both side-effects and treatment costs. In addition, any therapeutic antibody escaping from the local site of disease into the systemic circulation is immediately diluted within the large blood volume, further lowering the potential for unwanted effects. Needle-free topical application routes become an option when the condition is restricted locally to an external surface. The topical route may potentially be utilized in the form of eye drops for infections or corneal neovascularization or be applied to diseased skin for psoriasis, dermatitis, pyoderma gangrenosum, antibiotic resistant bacterial infections or ulcerated wounds. Diseases confined to the gastrointestinal tract can be targeted directly by applying antibody via the injection-free peroral route. The gastrointestinal tract is unusual in that its natural immuno-tolerant nature ensures the long-term safety of repeatedly ingesting heterologous antiserum or antibody materials. Without the stringent regulatory, purity and clean room requirements of manufacturing parenteral (injectable) antibodies, production costs are minimal, with the potential for more direct low-cost targeting of gastrointestinal diseases, especially with those caused by problematic antibiotic resistant or toxigenic bacteria (e.g. Clostridium difficile, Helicobacter pylori), viruses (e.g. rotavirus, norovirus) or inflammatory bowel disease (e.g. ulcerative colitis, Crohn's disease). Use of the oral route has previously been hindered by excessive antibody digestion within the gastrointestinal tract; however, this limitation may be overcome by intelligently applying one or more strategies (i.e. decoy proteins, masking therapeutic antibody cleavage sites, pH modulation, enzyme inhibition or encapsulation). These aspects are additionally discussed in this review and novel insights also provided. With the development of new applications via local injections, topical and peroral routes, it is envisaged that an extended range of ailments will increasingly fall within the clinical scope of therapeutic antibodies further expanding this market.

Risk of infections associated with biological treatment in inflammatory bowel disease

Tumor necrosis factor-α (TNF-α) inhibitors are biological agents introduced in the late 1990s for the treatment of different immune-mediated diseases as inflammatory bowel disease, rheumatoid arthritis and psoriasis. The most commonly used TNF-α antagonists are infliximab, adalimumab, and certolizumab pegol, and though highly effective in lowering inflammation, the efficacy must be weighed against the potential for adverse events. The treatment-induced immunosuppression is suspected to increase the risk of infections, including the risk of reactivation of latent tuberculosis, as the TNF-α cytokine plays an important role in the immune function. In this topic highlight a short overview of the infection risk associated with TNF-α inhibiter therapy is outlined with a focus on the overall risk of serious infections, mycobacterial infection and latent viral infections.

Anti-TNF therapy in Jordan: a focus on severe infections and tuberculosis

Background

A high rate of infection has been reported in patients receiving treatment with anti-tumor necrosis factor (anti-TNF). This study describes the rate of and risk factors for serious infections in patients receiving anti-TNF agents in Jordan.

Methods

This retrospective observational study was conducted at a large tertiary referral center in the north of Jordan. Between January 2006 and January 2012, 199 patients who received an anti-TNF agent (infliximab, adalimumab, or etanercept) were included. Patients received the anti-TNF treatment for rheumatoid arthritis, ankylosing spondylitis, inflammatory bowel disease, or other conditions. A serious infection was defined as any bacterial, viral, or fungal infection that required hospitalization, administration of appropriate intravenous antimicrobial therapy, and temporary withholding of anti-TNF treatment.

Results

The mean duration of anti-TNF treatment was 26.2 months. Steroids were used in 29.1% of patients, while 54.8% were given additional immunosuppressant therapy (methotrexate or azathioprine). Only one anti-TNF agent was given in 70.4% of patients, while 29.6% received different anti-TNF agents for the duration of treatment. Serious infections were documented in 39 patients (19.6%), including respiratory tract infections (41%), urinary tract infections (30.8%), and skin infections (20.5%), and extrapulmonary tuberculosis in three patients (7.7%). Exposure to more than one anti-TNF agent was the only factor associated with a significant increase in the rate of infection (relative risk 1.9, 95% confidence interval 1.06–4.0, P=0.03).

Conclusion

Serious infections, including tuberculosis, were a common problem in patients receiving anti-TNF agents, and exposure to more than one anti-TNF agent increased the risk of serious infection.

The role of Klebsiella in Crohn's disease with a potential for the use of antimicrobial measures

There is a general consensus that Crohn's disease (CD) develops as the result of immune-mediated tissue damage triggered by infections with intestinal microbial agents. Based on the results of existing microbiological, molecular, and immunological studies, Klebsiella microbe seems to have a key role in the initiation and perpetuation of the pathological damage involving the gut and joint tissues in patients with CD. Six different gastroenterology centres in the UK have reported elevated levels of antibodies to Klebsiella in CD patients. There is a relationship between high intake of starch-containing diet, enhanced growth of gut microbes, and the production of pullulanases by Klebsiella. It is proposed that eradication of these microbes by the use of antibiotics and low starch diet, in addition to the currently used treatment, could help in alleviating or halting the disease process in CD.

Current Phase II proprotein convertase subtilisin/kexin 9 inhibitor therapies for dyslipidemia

INTRODUCTION

Reduction of plasma low-density lipoprotein (LDL) cholesterol concentration with statins reduces adverse cardiovascular outcomes. However, lack of efficacy and intolerance of statins in many patients requires alternative treatments. Currently available non-statin alternatives include bile acid sequestrants, the cholesterol absorption inhibitor ezetimibe, niacin-based preparations and fibrates; however, each of these has limitations. Newer agents for LDL cholesterol reduction include the cholesterol ester transfer protein inhibitors, the microsomal triglyceride transfer protein inhibitor lomitapide, the apolipoprotein B antisense oligonucleotide mipomersen and several molecules that inhibit or interfere with proprotein convertase subtilisin/kexin 9 (PCSK9).

AREAS COVERED

Among the various PCSK9 inhibitors, human data are available for monoclonal antibodies against PCSK9 of which the two most advanced are alirocumab (SAR236553/REGN727) and AMG 145. Phase II studies of these agents as monotherapy or in combination with statins have shown reductions of LDL cholesterol by > 70%, with acceptable safety and tolerability so far.

EXPERT OPINION

Despite their biochemical efficacy, clinical efficacy, reflected by reduction of cardiovascular end points, remains to be shown for two leading monoclonal antibodies against PSCK9. Other issues to be evaluated with these agents over the longer term include development of rare adverse effects and potential attenuation of efficacy.