TNF-α antagonists beyond approved indications: stories of success and prospects for the future

Tumour necrosis factor alpha (TNF-α) is a key molecule of the inflammatory response and data derived from studies in experimental animal models and humans suggest that TNF-α may be implicated in the pathogenesis of various autoimmune and non-infectious inflammatory conditions. Over the past decade pharmaceutical agents directed against TNF-α (infliximab, adalimumab and etanercept) have been widely and successfully employed for the management of rheumatoid arthritis (RA), ankylosing spondylitis (AS), psoriasis, psoriatic arthritis, juvenile idiopathic arthritis and inflammatory bowel disease, whereas two novel anti-TNF-α agents, golimumab and certolimumab pegol, recently entered the market for the treatment of RA, AS, Crohn's disease and psoriasis. Encouraged by the positive results obtained from the use of TNF-α antagonists in terms of efficacy and safety and due to the increasingly accumulating evidence regarding the implication of TNF-α in the pathogenesis of numerous disorders, anti-TNF-α agents have been considered for the management of diseases other than the ones they were initially approved for. Although in the case of multiple sclerosis and chronic heart failure the outcome from the administration of TNF-α blockers had been less than favourable, in other cases of non-infectious inflammatory conditions the response to TNF-α inhibition had been fairly beneficial. More specifically, according to well-documented clinical trials, anti-TNF-α agents exhibited favourable results in Behçet's disease, non-infectious ocular inflammation, pyoderma gangrenosum and hidradenitis suppurativa. In this review we discuss the successful outcomes as well as the prospects for the future from the off-label use of TNF-α antagonists.

Myocardial performance and aortic elasticity are impaired in patients with ankylosing spondylitis

OBJECTIVE

To measure aortic stiffness and global left ventricular (LV) function in patients with ankylosing spondylitis (AS) and no clinical evidence of heart disease.

METHODS

Fifty-seven consecutive patients with AS (54 males, three females, mean age 41.78+/-10.02 years) without clinical evidence of cardiac involvement and 78 healthy subjects (73 males, five females, mean age 39.92+/-9.11 years) underwent complete echocardiographic study. Aortic stiffness was determined non-invasively by aortic distensibility (AoD) and the global LV function was evaluated by the myocardial performance index (the Tei index).

RESULTS

AoD in patients with AS [(2.21+/-0.24)x10(-6) cm(2) dyn(-1)] was decreased compared to controls [(2.58+/-0.19) )x10(-6) cm(2) dyn(-1), p<0.01], confirming that aortic stiffness is increased in AS. The LV Tei index was significantly increased in the patient group compared to the control group (0.392+/-0.031 vs. 0.370+/-0.034, p<0.01). The ejection fraction (EF) did not differ between the two groups (p>0.05). In multivariate linear regression analysis, AoD was significantly associated with the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and LV isovolumic relaxation time (IVRT) whereas the LV Tei index was associated with BASDAI and the LV mass index.

CONCLUSIONS

Patients with AS and no clinical evidence of cardiac disease have increased stiffness of the aorta and decreased global myocardial performance and both of these abnormal measurements correlate with disease activity. The abnormal Tei index may reflect an early manifestation of cardiac dysfunction in these patients.

Are clusters of patients with distinct clinical expression present in Behçet's disease?

OBJECTIVE

Studies from Israel and Turkey have proposed that patient clusters with discriminating clinical features may exist in Behçet's disease (BD); such clusters could help to better understand pathogenetic mechanisms and guide therapeutic decisions. Herein, we searched for specific associations between each disease manifestation to all other manifestations in Greek patients with BD.

METHODS

Specific clinical features were retrospectively recorded in 142 consecutive patients (80 men) fulfilling the International Study Group criteria, seen between 2000-2008 in our Departments (mean follow-up of 37 months). All possible associations between distinct clinical features were examined; further analysis in relation to HLA-B51 status and pathergy test positivity, available in 89 patients, was performed.

RESULTS

No significant associations between various manifestations of BD were found, either among all patients, or among men or women analysed separately. Uveitis was present more frequently in men, but not women, who were HLA-B51 carriers (p<0.02). A positive pathergy reaction was associated with oral ulcers (p<0.001) and central nervous involvement (p=0.008) in women, and folliculitis in men (p=0.046).

CONCLUSION

In contrast to studies from other countries, no subgroups of patients with distinct positive or negative associations between clinical features were found. HLA-B51 may have some prognostic significance in men only. Whether differences in disease expression between geographical areas may reflect different triggers of pathogenetic mechanisms operating among ethnic groups could be further explored in comparative studies.

Management of Behçet disease: a systematic literature review for the European League Against Rheumatism evidence-based recommendations for the management of Behçet disease

OBJECTIVES

To present and analyse the literature sources regarding the management of Behçet disease (BD) identified during the systematic literature research, which formed the basis for the European League Against Rheumatism (EULAR) evidence-based recommendations for the management of BD.

METHODS

Problem areas and related keywords regarding the management of BD were determined by the multidisciplinary expert committee commissioned by EULAR for developing the recommendations. A systematic literature research was performed using MedLine and Cochrane Library resources through to December 2006. Meta-analyses, systematic reviews, randomised controlled trials (RCTs), open studies, observational studies, case control studies and case series' involving > or = 5 patients were included. For each intervention the effect size and number needed to treat were calculated for efficacy. Odds ratios and numbers needed to harm were calculated for safety issues of different treatment modalities where possible.

RESULTS

The literature research yielded 137 articles that met the inclusion criteria; 20 of these were RCTs. There was good evidence supporting the use of azathioprine and cyclosporin A in eye involvement and interferon (IFN)alpha in mucocutaneous involvement. There were no RCTs with IFNalpha or tumour necrosis factor (TNF)alpha antagonists in eye involvement. Similarly controlled data for the management of vascular, gastrointestinal and neurological involvement is lacking.

CONCLUSION

Properly designed, controlled studies (new and confirmatory) are still needed to guide us in managing BD.

Improvement of vascular endothelial function using the oral endothelin receptor antagonist bosentan in patients with systemic sclerosis

OBJECTIVE

Increased endothelin activity may play a role in the pathogenesis of vascular injury, a primary feature of systemic sclerosis (SSc; scleroderma). Our goal was to test the hypothesis that treatment with the oral endothelin receptor antagonist bosentan might improve vascular endothelial function in SSc patients.

METHODS

A 4-week, prospective, parallel-group study compared 12 SSc patients who did not receive bosentan treatment with 12 patients who did receive treatment (125 mg/day) for pulmonary hypertension and/or digital ulcers. There were no differences in demographic and clinical characteristics or medications between the 2 groups. Baseline endothelial dysfunction was documented by decreased brachial artery ultrasound-derived flow-mediated dilation (FMD%; <5.5). Pulse wave analysis, venous occlusion plethysmography, and measurement of serum vascular markers were performed in parallel.

RESULTS

FMD%, the main end point, increased significantly from a mean +/- SD of 3.1 +/- 1.3% to 8.4 +/- 2.6% after 4 weeks of bosentan treatment (P < 0.001, compared with a change from 2.4 +/- 1.6% to 2.4 +/- 2.2% in control patients). Arterial blood pressure, endothelium-independent vascular function, augmentation index, peripheral flow reserve, as well as circulating intercellular adhesion molecule 1, E-selectin, vascular endothelial growth factor, and endothelin 1 were not significantly affected by bosentan treatment. In patients continuously treated for 4 months, during which the dosage of bosentan remained at 125 mg/day (n = 5) or increased to 250 mg/day (n = 5), the 4-week results remained unchanged.

CONCLUSION

Small doses of bosentan improve endothelial function without affecting hemodynamic parameters or endothelial activation-related processes, thus supporting a direct, reversible effect of endothelin in SSc-associated vascular injury. A long-term, controlled trial to examine the potentially global clinical benefit of endothelin receptor blockade in patients with early SSc may be warranted.

Infliximab treatment-induced formation of autoantibodies is common in Behçet's disease

OBJECTIVE

To study autoantibody formation in patients with Behçet's disease (BD) who received long-term treatment with the anti-TNF monoclonal antibody infliximab.

METHODS

Serial sera from infliximab-treated patients (5 mg/kg at weeks 0, 4, 8, and every 6-8 weeks thereafter) were tested for various autoantibodies, using commercially available methods, at baseline and at 6 months (n = 20), at 12 months (n = 16), and at 18 months post-baseline (n = 12). Thirty-five age- and sex-matched BD patients, not treated with infliximab, served as controls.

RESULTS

Autoantibodies were rarely seen in controls, as well as in infliximab treated patients at baseline. Formation of antinuclear antibodies (ANA) at low titers was evident in 13/20 (65%) patients at 6 months post-baseline; one additional patient developed anti-beta2 glycoprotein-I IgM antibodies (anti-beta(2)GPI). Of the 13 ANA-positive sera, low titers-IgM of anti-dsDNA or anti-beta(2)GPI were detected in 7 (35%) and 6 (30%) patients, respectively. Additional measurements at 12 and 18 months showed that the persistence and/or increasing titers of these autoantibodies depended on continuation of treatment. Antibodies to extractable nuclear antigens (anti-RNP, anti-SS-A/Ro, anti-SS-B/La, anti-Sm), rheumatoid factors, anti-cyclic citrullinated peptide antibodies and antineutrophil cytoplasmic antibodies, were never detected. No antibody-related symptoms, lupus-like disease, or thrombosis were observed in any patient up to 18 months of follow-up.

CONCLUSION

Early induction of ANA and specific autoantibodies is common in BD patients treated with infliximab, including low titers of non-pathogenic anti-dsDNA and anti-Beta<inf>2</inf>GPI antibodies. A possible clinical significance of these findings needs to be documented in further studies, including more patients and longer follow-up periods.

Increased expression of the FoxP3 functional marker of regulatory T cells following B cell depletion with rituximab in patients with lupus nephritis

B cell depletion may affect T cell activation and costimulation status in rituximab-treated patients with SLE. We examined whether rituximab administration in patients with active lupus nephritis is related to changes in mRNA expression of genes that define regulatory T cells (Tregs) in peripheral blood lymphocytes, measured by real-time PCR. At the early phase of B cell depletion mRNA levels of CD25, CTLA-4, GITR and the bona fide Treg functional marker FOXP3 increased significantly in all 7 patients examined. In contrast, mRNA levels of the costimulatory/activation T cell molecule CD40L were profoundly reduced, while mRNA levels of TGF-beta, a cytokine contributing to Treg induction, increased significantly in all. During follow-up, increased FOXP3 mRNA persisted in those patients in clinical remission, while in those patients with active disease subsequent decreases were noted. Further studies should examine whether modulation of Tregs by therapeutic B cell depletion contributes and/or predicts lupus disease remission.

Gene therapy in systemic lupus erythematosus

Despite the fact that the etiopathogenesis of systemic lupus erythematosus is largely unknown, key steps in the pathophysiology of the disease have been recognized and targeted using gene therapy techniques. In animal models of lupus, gene transfer has been used to block the action of pro-inflammatory cytokines and co-stimulatory molecules leading to clinical improvement. In humans, ex vivo experiments have shown the feasibility of gene transfer in live T cells and its potential for restoring normal phenotype in T cells from patients with lupus. Still in experimental phase, gene therapy in lupus promises to correct the aberrant immunological response without the numerous side-effects of the currently used immunosuppressant medications.

Tuberculosis and granuloma formation in patients receiving anti-TNF therapy

In patients receiving anti-tumor necrosis factor (TNF) therapy, a probable exacerbation of latent tuberculosis (TB) is a major adverse event. The impairment of granuloma differentiation is considered a characteristic feature of TB in these patients. In this report we present three patients with rheumatic disease who developed TB under infliximab treatment. All of them had typical granulomas on the biopsy specimens, indicating that the expected impairment of granuloma formation is not always the case. The notion of granuloma-free TB in patients receiving anti-TNF therapy could shift a clinician's path away from performing a biopsy, thus delaying the establishment of a correct diagnosis.

Age-related thymic activity in adults following chemotherapy-induced lymphopenia

BACKGROUND

The potential role of the adult thymus in T-cell homeostasis subsequent to lymphopenia remains the subject of debate. We examined whether thymic activity contributes to reconstitution of the peripheral T-cell pool, a critical process for patients recovering from antineoplastic therapy.

METHODS

In selected patients with various neoplastic diseases we assessed peripheral blood lymphocyte subsets by flow-cytometry, including thymus-derived, CD4+ T cells expressing the CD45RA molecule, and thymic size rebound by CT scan before, and 3, 6 and 12 months after completion of cytotoxic therapy.

RESULTS

Adult patients (n = 21, mean age of 30 years, range 18-49) had higher baseline numbers of B and lower numbers of NK cells than elderly patients (n = 15, mean age of 79 years, range 70-91), while total T-cell numbers did not differ. Despite the reduction of lymphocyte counts being comparable in the adult (mean of 45%) and elderly (mean of 49%) groups, occurring at, or near, completion of treatment, an enlargement of the previously atrophic thymus was evident in 63% of the adult, but in none of the elderly, subjects. In 22 patients who remained active disease-free during the following year, B cells and NK cells recovered to pretreatment levels as soon as at 3 months, whereas overall T-cell recovery occurred at 6 months post-treatment. Thymic rebound, observed in 11 of 22 patients who were of younger age, correlated significantly with a faster and more complete recovery of CD45RA+ CD4+ (mainly helper-naïve) T cells.

CONCLUSION

The adult thymus appears capable of regeneration, at least up to middle age, contributing significantly to the reconstitution of the peripheral T-cell pool following chemotherapy-induced lymphopenia. In advanced age, however, although peripheral homeostatic pathways appear intact, regeneration of the naïve repertoire is incomplete.

Psoriasis induced by anti-tumor necrosis factor therapy: A paradoxical adverse reaction

Administration of anti-tumor necrosis factor (anti-TNF) agents is beneficial in a variety of chronic inflammatory conditions, including psoriasis. We describe 5 patients in whom psoriasiform skin lesions developed 6-9 months after the initiation of anti-TNF therapy for longstanding, seropositive rheumatoid arthritis (etanercept or adalimumab), typical ankylosing spondylitis (infliximab), and Adamantiades-Behçet's disease (infliximab). In all 5 patients, the underlying disease had responded well to anti-TNF therapy. Four patients developed a striking pustular eruption on the palms and/or soles accompanied by plaque-type psoriasis at other skin sites, while 1 patient developed thick erythematous scaly plaques localized to the scalp. In 3 patients there was nail involvement with onycholysis, yellow discoloration, and subungual keratosis. Histologic findings from skin biopsies were consistent with psoriasis. None of these patients had a personal or family history of psoriasis. In all patients, skin lesions subsided either with topical treatment alone, or after discontinuation of the responsible anti-TNF agent. The interpretation of this paradoxical side effect of anti-TNF therapy remains unclear but may relate to altered immunity induced by the inhibition of TNF activity in predisposed individuals.

Aortic stiffness in systemic sclerosis is increased independently of the extent of skin involvement

OBJECTIVE

To study the stiffness of large arteries in relation to the extent of skin and lung fibrosis, aortic distensibility was examined in patients with diffuse and limited systemic sclerosis (SSc).

METHODS

Consecutive patients (55 with diffuse and 51 with limited SSc) without signs and symptoms of heart failure or a previous history of arterial hypertension underwent echocardiography and lung function tests. Aortic stiffness was determined non-invasively by aortic distensibility and aortic strain measurements in all patients and in 50 healthy subjects, matched for age and gender.

RESULTS

Aortic distensibility in patients with either diffuse (2.03 +/- 0.26 x 10(-6) cm(2) dyn(-1)) or limited SSc (2.12 +/- 0.33) was similarly decreased compared with controls (2.49 +/- 0.36, P<0.001). Moreover, aortic strain was significantly reduced in both patient groups compared with controls, confirming that aortic stiffness is increased in SSc independently of the extent of skin involvement. Left ventricular performance was similar between patients and controls, while left ventricular mass and tricuspid systolic gradient were significantly increased in both SSc groups, the latter being associated with aortic stiffness in multivariate analysis. No association with serum levels of C-reactive protein or lung function abnormalities indicative of pulmonary fibrosis were found.

CONCLUSIONS

Stiffness of the aorta is increased in patients with established SSc regardless of the extent of the inflammatory fibrotic process in the skin and lungs, suggesting that additional pathogenetic mechanisms contribute to the compromise of large arteries.

13q deletion in chronic lymphocytic leukemia: characterization of E4.5, a novel chromosome condensation regulator-like guanine nucleotide exchange factor

We report the characterization of a new gene (E4.5) that maps at chromosome band 13q14.3, a chromosomal area frequently deleted in chronic lymphocytic leukemia (CLL) and in other lymphoid malignancies. E4.5 gene encodes for a 4 kb mRNA expressed in various tissues and has an open reading frame of 531 amino acids. The predicted E4.5 protein shows strong homology with the human regulator of chromosome condensation (RCC1) protein, the principal GTP exchange factor for Ran protein. The E4.5 protein contains a BTB domain in its N-terminus, a protein-protein interaction motif. Therefore, we propose that E4.5 is a new member of the RCC1-related guanine nucleotide exchange factor (GEF) family with potent interaction with other proteins and unknown function. Until now, no tumor suppressor genes have been mapped in the 13q14.3 minimal deleted region (MDR) in patients with CLL. It has been proposed that loss of the 13q14.3 MDR may contribute to lymphoid neoplasia by altering the expression/function of genes located on 13q14.3 outside the MDR. The E4.5 is one of these genes with a potential role in the pathogenesis of CLL.

Behçet's disease: a new target for anti-tumour necrosis factor treatment

Behçet's disease is a multisystemic, chronic relapsing inflammatory disease classified among the vasculitides. Recurrent mucocutaneous lesions may be the only symptoms in mild cases, but articular, ocular, vascular, and/or gastrointestinal and central nervous system involvement may occur in most of the patients. Ocular disease is the most frequent cause of morbidity leading to blindness in 25% of those affected. The various non-specific immunosuppressive drugs, used either alone or in combinations, frequently fail to control inflammation or maintain remissions. The aetiology of Behçet's disease is unknown, however it is currently thought that a central pathogenetic role of tumour necrosis factor (TNF) in the inflammatory process is possible. Until June 2002, and according to published and anecdotal data, more than 80 patients from 10 different countries have received anti-TNF treatment. The short-term effects of the anti-TNF monoclonal antibody infliximab have been reported in several case reports and small case series, whereas the effects of etanercept have been presented in recent conferences. Preliminary results strongly suggest that infliximab is remarkably effective in inducing short-term remission of almost all manifestations of the disease, including acute, sight threatening panuveitis. A double blind, placebo controlled, one month study on the efficacy of etanercept in suppressing the mucocutaneous manifestations of the disease showed beneficial results. To date, significant side effects have not been reported. It seems that TNF block is an effective new treatment for patients with Behçet's disease. Whether such treatment is superior to the conventional therapeutic approaches in preventing relapses and progression of the disease remains to be determined by carefully controlled studies. At least three open, long term studies, including larger numbers of patients are currently being conducted.

CD40L overexpression on T cells and monocytes from patients with systemic lupus erythematosus is resistant to calcineurin inhibition

To explore the regulatory defects underlying the overexpression of CD40 ligand (CD40L, CD154) in human lupus we studied the effects of cyclosporin-A (CsA), which blocks Ca2+/calcineurin-dependent CD40L gene expression, on peripheral blood-derived T cells and monocytes. In contrast to control subjects, CsA failed to inhibit the prolonged CD40L expression observed in vitro on anti-CD3-activated lupus T cells. Resistance to CsA was not restricted to CD4+ or CD8+ T cell subsets and was disease activity-independent. Experiments assessing the effects of dexamethasone on CD40L expression, as well as of CsA on the early activation marker CD69 expression and on surface CD40L cleavage, confirmed the unique regulation of CD40L in lupus T cells. On the other hand, co-culture with anti-CD3-activated T cells caused surface CD40L expression on monocytes, which was not an Fc receptor-mediated event. Lupus monocytes clearly overexpressed CD40L comparing to healthy and disease-control monocytes, and, similarly to lupus T cells, displayed a prominent resistance to CsA inhibitory effects. These findings indicate that, besides Ca2+/calcineurin-dependent mechanisms, other pathways are involved in the dysregulation of CD40L in SLE immune cells, dissection of which may have important therapeutic implications.