Anti-TNF agents for rheumatoid arthritis

Development of myeloperoxidase-antineutrophil cytoplasmic antibody-associated renal vasculitis in a patient receiving treatment with anti-tumor necrosis factor-α

We report on a 33-year-old woman who presented with positive myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) during rheumatoid arthritis treatment with infliximab. She had a history of worsening arthralgia, and urinalysis showed the new occurrence of hematuria and proteinuria. Renal biopsy showed necrotizing crescentic glomerulonephritis. Immunosuppressive therapy and discontinuation of the infliximab therapy alleviated her arthralgia and improved the urinalysis results. We report this rare case in which an anti-tumor necrosis factor-α (TNF-α) agent for ANCA-associated systemic vasculitis was studied.

A variant of TNFR2-Fc fusion protein exhibits improved efficacy in treating experimental rheumatoid arthritis

Etanercept, a TNF receptor 2-Fc fusion protein, is currently being used for the treatment of rheumatoid arthritis (RA). However, 25% to 38% of patients show no response which is suspected to be partially due to insufficient affinity of this protein to TNFα. By using computational protein design, we found that residue W89 and E92 of TNFR2 were critical for ligand binding. Among several mutants tested, W89Y/E92N displayed 1.49-fold higher neutralizing activity to TNFα, as compared to that of Etanercept. Surface plasmon resonance (SPR) based binding assay revealed that the equilibrium dissociation constant of W89Y/E92N to TNFα was 3.65-fold higher than that of Etanercept. In a rat model of collagen-induced arthritis (CIA), W89Y/E92N showed a significantly better ability than Etanercept in reducing paw swelling and improvement of arthritic joint histopathologically. These data demonstrate that W89Y/E92N is potentially a better candidate with improved efficacy in treating RA and other autoimmune diseases.

Rheumatoid arthritis (RA) is a frequently occurring, chronic, debilitating disease. TNFα plays a pivotal role in regulating its inflammatory response. TNFα inhibition with TNF receptor 2-Fc fusion protein (TNFR2-Fc) was effective in the treatment of RA. However, quite a few patients may not achieve good clinical outcomes after TNFR2-Fc therapy, and the high dosage of TNFR2-Fc in clinical treatment usually causes some side effects, such as injection site reactions. Enhancing the affinity of TNFR2-Fc to TNFα would be of benefit to its therapeutic effect on RA, and may reduce the clinical dosage. We modeled the interactions of TNFα and TNFR2, and figured out the sites that may be critical for ligand-receptor binding. A high affinity TNFR2-Fc variant (E92N/W89Y) was obtained by rational mutagenesis at residue 89 and 92. It shows significant improvements compared with wild type TNFR2-Fc in suppressing rat arthritis induced by collagen. This variant is more potent in neutralizing TNFα, and thereafter may offer a higher degree of RA symptom relief, and be in a much lower dosage.

Improvement in patient-reported outcomes in a rituximab trial in patients with severe rheumatoid arthritis refractory to anti-tumor necrosis factor therapy

OBJECTIVE

To assess the effects of treatment with rituximab plus methotrexate on patient-reported outcomes in patients with active rheumatoid arthritis (RA) who experienced inadequate response to anti-tumor necrosis factor therapy.

METHODS

Patients with active RA were randomly assigned to rituximab (1,000 mg on days 1 and 15) or placebo. The primary end point was the proportion of patients with an American College of Rheumatology 20% response at week 24. Additional goals were to assess treatment effects on pain, fatigue, functional disability, health-related quality of life, and disease activity by comparing mean changes between groups. The analysis was conducted in the intent-to-treat population. The proportion of patients who achieved the minimum clinically important difference on the Health Assessment Questionnaire (HAQ) disability index (DI), Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F), and Short Form 36 (SF-36) was determined.

RESULTS

Rituximab patients had statistically significantly greater pain relief. The FACIT-F showed significantly greater improvement in rituximab patients than placebo patients from weeks 12 through 24. Mean improvement from baseline in functional disability (measured by the HAQ DI) was significantly greater in rituximab patients from weeks 8 to 24. The mean +/- SD change from baseline for the SF-36 Physical Component Score was 6.64 +/- 8.74 for rituximab patients and 1.48 +/- 7.32 for placebo patients (P < 0.0001). The mean change from baseline for the SF-36 Mental Component Score was 5.32 +/- 12.41 for rituximab patients and 2.25 +/- 12.23 for placebo patients (P = 0.0269).

CONCLUSION

Rituximab produced rapid, clinically meaningful, and statistically significant improvements in patient-reported pain, fatigue, functional disability, health-related quality of life, and disease activity. These effects were sustained throughout the study.

Tumor necrosis factor-alpha antagonists and neuropathy

Tumor necrosis factor (TNF)-alpha plays an important role in many aspects of immune system development, immune-response regulation, and T-cell-mediated tissue injury. The evidence that TNF-alpha, released by autoreactive T cells and macrophages, may contribute to the pathogenesis of immune-mediated demyelinating neuropathies is reviewed. TNF-alpha antagonists (infliximab, etanercept, adalimumab) are indicated for the treatment of advanced inflammatory rheumatic and bowel disease, but these drugs can induce a range of autoimmune diseases that also attack the central and peripheral nervous systems. Case histories and series report on the association between anti-TNF-alpha treatment and various disorders of peripheral nerve such as Guillain-Barré syndrome, Miller Fisher syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy with conduction block, mononeuropathy multiplex, and axonal sensorimotor polyneuropathies. The proposed pathogeneses of TNF-alpha-associated neuropathies include both a T-cell and humoral immune attack against peripheral nerve myelin, vasculitis-induced nerve ischemia, and inhibition of signaling support for axons. Most neuropathies improve over a period of months by withdrawal of the TNF-alpha antagonist, with or without additional immune-modulating treatment. Preliminary observations suggest that TNF-alpha antagonists may be useful as an antigen-nonspecific treatment approach to immune-mediated neuropathies in patients with a poor response to, or intolerance of, standard therapies, but further studies are required.

ANCA-associated renal vasculitis following anti-tumor necrosis factor alpha therapy

We report the case of a 62-year-old woman with rheumatoid arthritis treated with adalimumab, an anti-tumor necrosis factor alpha drug, who presented with 4 weeks of lethargy, upper respiratory tract symptoms, a vasculitic skin rash, and rapidly deteriorating renal function. She had cytoplasmic antineutrophil cytoplasmic antibodies and skin and renal biopsy specimens diagnostic of small vessel vasculitis and necrotizing crescentic glomerulonephritis, respectively. After immunosuppressive therapy and discontinuation of adalimumab therapy, vasculitis resolved and renal function recovered. This is the first report of antineutrophil cytoplasmic antibody associated necrotizing glomerulonephritis with adalimumab.

The design and synthesis of novel alpha-ketoamide-based p38 MAP kinase inhibitors

We have identified a novel series of potent p38 MAP kinase inhibitors through structure-based design which due to their extended molecular architecture bind, in addition to the ATP site, to an allosteric pocket. In vitro ADME and in vivo PK studies show these compounds to have drug-like characteristics which could result in the development of an oral treatment for inflammatory conditions.

Benzothiazole based inhibitors of p38alpha MAP kinase

Rational design, synthesis, and SAR studies of a novel class of benzothiazole based inhibitors of p38alpha MAP kinase are described. The issue of metabolic instability associated with vicinal phenyl, benzo[d]thiazol-6-yl oxazoles/imidazoles was addressed by the replacement of the central oxazole or imidazole ring with an aminopyrazole system. The proposed binding mode of this new class of p38alpha inhibitors was confirmed by X-ray crystallographic studies of a representative inhibitor (6a) bound to the p38alpha enzyme.

Pyrrolopyridine Inhibitors of Mitogen-Activated Protein Kinase-Activated Protein Kinase 2 (MK-2)

A new class of potent kinase inhibitors selective for mitogen-activated protein kinase-activated protein kinase 2 (MAPKAP-K2 or MK-2) for the treatment of rheumatoid arthritis has been prepared and evaluated. These inhibitors have IC50 values as low as 10 nM against the target and have good selectivity profiles against a number of kinases including CDK2, ERK, JNK, and p38. These MK-2 inhibitors have been shown to suppress TNFalpha production in U397 cells and to be efficacious in an acute inflammation model. The structure-activity relationships of this series, the selectivity for MK-2 and their activity in both in vitro and in vivo models are discussed. The observed selectivity is discussed with the aid of an MK-2/inhibitor crystal structure.

Suppression of NF-kappaB activation by curcumin leads to inhibition of expression of cyclo-oxygenase-2 and matrix metalloproteinase-9 in human articular chondrocytes: Implications for the treatment of osteoarthritis

Pro-inflammatory cytokines such as interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) play a key role in the pathogenesis of osteoarthritis (OA). Anti-inflammatory agents capable of suppressing the production and catabolic actions of these cytokines may have therapeutic potential in the treatment of OA and a range of other osteoarticular disorders. The purpose of this study was to examine the effects of curcumin (diferuloylmethane), a pharmacologically safe phytochemical agent with potent anti-inflammatory properties on IL-1beta and TNF-alpha signalling pathways in human articular chondrocytes maintained in vitro. The effects of curcumin were studied in cultures of human articular chondrocytes treated with IL-1beta and TNF-alpha for up to 72h. Expression of collagen type II, integrin beta1, cyclo-oxygenase-2 (COX-2) and matrix metalloproteinase-9 (MMP-9) was monitored by western blotting. The effects of curcumin on the expression, phosphorylation and nuclear translocation of protein components of the NF-kappaB system were studied by western blotting and immunofluorescence, respectively. Treatment of chondrocytes with curcumin suppressed IL-1beta-induced NF-kappaB activation via inhibition of IkappaBalpha phosphorylation, IkappaBalpha degradation, p65 phosphorylation and p65 nuclear translocation. Curcumin inhibited the IL-1beta-induced stimulation of up-stream protein kinase B Akt. These events correlated with down-regulation of NF-kappaB targets including COX-2 and MMP-9. Similar results were obtained in chondrocytes stimulated with TNF-alpha. Curcumin also reversed the IL-1beta-induced down-regulation of collagen type II and beta1-integrin receptor expression. These results indicate that curcumin has nutritional potential as a naturally occurring anti-inflammatory agent for treating OA through suppression of NF-kappaB mediated IL-1beta/TNF-alpha catabolic signalling pathways in chondrocytes.

Inhibition of inducible tumor necrosis factor-α expression by the fungal epipolythiodiketopiperazine gliovirin

TNF-alpha is a major pro-inflammatory cytokine that regulates further cytokine induction, especially of IL-1 and IL-6, in many human diseases including cancer, inflammation and immune disorders. In a search for new inhibitors of inducible TNF-alpha promoter activity and expression, cultures of the imperfect fungus Trichoderma harzianum were found to produce gliovirin, a previously isolated epipolythiodiketopiperazine. Gliovirin inhibited inducible TNF-alpha promoter activity and synthesis in LPS/IFN-gamma-stimulated macrophages/monocytes and Jurkat T-cells, co-stimulated with 12-O-tetradecanoylphorbol-13-acetate (TPA)/ionomycin, in a dose-dependent manner, with IC(50) values ranging from 0.21 to 2.1 microM (0.1-1 microg/ml). Studies on the mode of action revealed that gliovirin suppresses TNF-alpha synthesis by inhibiting the activation of extracellular signal-regulated kinase (ERK), thereby blocking the pathway leading to activation of the transcription factors AP-1 and NF-kappaB, the latter of which is involved in the inducible expression of many pro-inflammatory genes. Gliovirin also significantly reduced TPA/ionomycin-induced IL-2 mRNA levels and synthesis in Jurkat cells at low micromolar concentrations.

Etanercept: effective in the management of hidradenitis suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic suppurative condition which is poorly responsive to treatment and is characterized by significant morbidity. Successful treatment of HS in patients treated with infliximab for concomitant Crohn's disease has been reported. More recent reports of positive responses to infliximab [an antitumour necrosis factor (TNF)-alpha agent] in patients who have HS but not Crohn's disease are encouraging.

OBJECTIVES

TNF-alpha is implicated in many inflammatory disorders and we wished to determine the efficacy of subcutaneous etanercept, a competitive inhibitor of TNF-alpha in the control of HS symptoms.

METHODS

We commenced six patients with severe, recalcitrant HS on etanercept (25 mg subcutaneously twice weekly in all cases). All patients had a normal chest X-ray and negative purified protein derivative test prior to treatment and were closely monitored throughout the treatment period for signs of infection. Patients self-assessed their disease activity and completed Dermatology Life Quality Index (DLQI) questionnaires immediately before the introduction of therapy and 24 weeks later in the case of four patients, and 12 weeks later in the case of two others. All patients were asked to estimate the time lapse between commencement of treatment and initial response.

RESULTS

Treatment was well tolerated by all patients with no reported adverse reactions. A marked reduction in self-reported disease activity (mean reduction of 61% at 24 weeks), in DLQI scores (mean reduction of 64% at 24 weeks) and in relapse rates occurred. All patients rated etanercept as their most effective treatment to date.

CONCLUSIONS

Our results show the effectiveness of etanercept in this group of patients with particularly challenging disease. Etanercept, unlike infliximab, may be administered subcutaneously, rendering costly day-case admissions unnecessary.

Fusion protein of CDR mimetic peptide with Fc inhibit TNF-α induced cytotoxicity

The variable regions of antibodies play central roles in the binding with antigens. Based on the model of a tumour necrosis factor-alpha (TNF-alpha) neutralizing monoclonal antibody (named as Z12) with TNF-alpha, heavy chain CDR2 (HCDR2) and light chain CDR3 (LCDR3) of Z12 were found to be the most responsible to bind with TNF-alpha. A mimetic peptide (PT) was designed based on the sequence derived from HCDR2 and LCDR3. Fusion protein PT-Fc was constructed by linking PT with Fc of human IgG1 through a flexible linker (GGGGGS). The primary structural characteristics of Fc and PT-Fc were analyzed, including the flexibility, hydrophilicity and epitopes. It was demonstrated that PT and Fc in the fusion protein possessed bio-function properly and non-interfering with each other. Furthermore, PT-Fc was expressed in Escherichia coli by fusion with thioredoxin (Trx). After trx-PT-Fc was cleaved with recombinant enterokinase, PT-Fc was obtained. The results of in vitro cytotoxic assays showed that both PT and PT-Fc could efficiently inhibit TNF-alpha induced apoptosis on L929 cells. At the same micromole concentration, the inhibition activity of PT-Fc was significantly higher than PT.

5-Cyanopyrimidine Derivatives as a Novel Class of Potent, Selective, and Orally Active Inhibitors of p38α MAP Kinase

A novel class of 5-cyanopyrimidine-based inhibitors of p38alpha MAP kinase has been investigated. Analogues optimized through SAR iterations display low nanomolar enzymatic and cellular activity. The in vivo efficacy of this class of p38 inhibitors was demonstrated by 3a and 3b (>50% reduction in TNF levels when orally dosed at 5 mg/kg, 5 h prior to LPS administration in an acute murine model of inflammation). For 3a and 3b, the previously identified N-methoxybenzamide moiety (1) was replaced with N-(isoxazol-3-yl)benzamide, thereby providing increased metabolic stability. Cyanopyrimidine 3a demonstrated 100% oral bioavailability in mouse. High p38 kinase selectivity versus over 20 kinases was observed for analogue 3b. Direct hydrogen bonding of the cyano nitrogen of the 5-cyanopyrimidine core to the backbone NH of Met109 was confirmed by X-ray crystallographic analysis of 3a bound to p38alpha.

A novel TNFalpha antagonizing peptide-Fc fusion protein designed based on CDRs of TNFalpha neutralizing monoclonal antibody

The variable regions of antibody molecules bind antigens with high affinity and specificity. The binding sites are imparted largely to the hypervariable portions (i.e., CDRs) of the variable region. Peptides derived from CDRs can bind antigen with similar specificity acting as mimic of antibody and become drug-designing core, although with markedly lower affinity. In order to increase the affinity and bioactivity, in this study, a novel peptide (PT) designed on CDRs of a TNFalpha neutralizing monoclonal antibody Z12 was linked with Fc fragment of human IgG1. The interaction mode of PT-linker-Fc (PLF) with TNFalpha was analyzed with computer-guided molecular modeling method. After expression in Escherichia coli and purification, recombinant PT-linker-Fc could bind directly with the TNFalpha coated on the ELISA plates. Furthermore, PLF could competitively inhibit the binding of Z12 to TNFalpha and also inhibit the TNFalpha-induced cytotoxicity on L929 cells. The TNFalpha antagonizing activity of PLF was significantly higher than that of the free peptide. This study highlights the potential of human Fc to enhance the potency of peptides designed on the CDRs of antibodies and could be useful in developing new TNFalpha antagonists.

Sepsis as a Possible Adverse Drug Reaction in Patients With Rheumatoid Arthritis Treated With TNFα Antagonists

BACKGROUND

Clinical improvement during the treatment of rheumatoid arthritis (RA) with the TNFalpha antagonists has been well documented. Our knowledge of uncommon adverse drug reactions (ADRs) with these new drugs is more restricted. Concerns have been raised that these types of drugs could cause an increased frequency of infections, and already existing infections are named as contraindications in the product labels.

METHODS

In Sweden, it is compulsory for healthcare professionals with permission to prescribe drugs to report suspected ADRs to the regulatory authority, the Medical Product Agency (MPA). At the 6 regional centers that are established in Sweden, a preliminary causality assessment is made and the data is transferred online to a database.

RESULTS

Between January 1, 1999, and June 30, 2003, 29 cases of sepsis were reported as suspected adverse effects caused by drugs. Seventeen of these cases concerned TNFalpha antagonists. The MPA has received 3 reports of septicemia in patients from Northern Sweden treated with the TNFalpha antagonist etanercept. In submitting these reports, factors that can contribute to susceptibility and to more fatal courses of serious infections are taken into consideration. Demographic and pharmaceutical factors as well as risks from predisposing conditions are discussed in connection with the cases in this report.

CONCLUSION

There is a need for more information to physicians to be aware of sepsis as a possible and serious ADR during treatment with TNF antagonists, and that patients with predisposing diseases or those who do not regularly visit their rheumatologist could be at higher risk.

Influence of rheumatoid arthritis in the enantioselective disposition of fenoprofen

To investigate the influence of rheumatoid arthritis on the stereoselective disposition of fenoprofen administered as a racemic mixture, eight patients with rheumatoid arthritis receiving calcium rac-fenoprofen (200 mg/8 h) and 7 healthy volunteers given single oral dose (600 mg) were investigated. Serial blood samples and urine were collected from zero to 24 h after fenoprofen (FEN) administration. The following differences were observed between the (+)-(S) and (-)-(R)-FEN in the patients with rheumatoid arthritis (means 95% CI, Wilcoxon test, P < 0.05): C(max) 14.1 (12.5-15.8) versus 3.6 (2.5-4.7) microg/ml; AUC(ss) (0-8) 80.5 (67.3-93.7) versus 12.1 (8.8-15.4) microg.h/ml; Cl(T)/f 1.3 (1.0-1.5) versus 9.1 (6.5-11.8) l/h; and t(1/2) 3.1 (2.3-3.9) versus 1.2 (0.8-1.6) h. The Cl(T)/f of (-)-(R)-FEN was reduced in patients with rheumatoid arthritis when compared to healthy volunteers: 9.1 (6.5-11.8) versus 17.4 (13.9-20.9) l/h; P < 0.05 Mann-Whitney test. The administration of rac-FEN as a single dose to healthy volunteers or multiple doses to patients with rheumatoid arthritis resulted in lower Cl(T)/f for the (+)-(S)-FEN. The lower Cl(T)/f of (-)-(R)-FEN observed for patients with rheumatoid arthritis is consistent with lower clearance by inversion, although other metabolic pathways, drug interactions, and bioavailability of the individual enantiomers may also contribute to the difference.

Identification of anti-TNFalpha peptides with consensus sequence

Phage displayed peptide library was used to select tumor necrosis factor alpha (TNFalpha) binding peptides. After three sequential rounds of biopanning, some linear TNFalpha-binding peptides were identified from a 12-mer peptide library. A consensus sequence (L/M)HEL(Y/F)(L/M)X(W/Y/F), where X might be variable residue, was deduced from sequences of these peptides. The phages bearing these peptides showed specific binding to immobilized TNFalpha, with over 80% of phages bound being competitively eluted by free TNFalpha. To confirm the binding activity and to explore further functional properties, three peptides with typical structure were selected and expressed as GST-fused protein. These recombinant peptides effectively competed for [125I]TNFalpha binding to TNFR1 in a dose-dependent manner, with IC(50) from 10 to 160 microM. Furthermore, the GST-fused derivatives showed inhibitory effects on TNFalpha-induced cytotoxicity. Taken together, these data demonstrate that the TNFalpha-binding peptides are effective antagonists of TNFalpha and the deduced motif might be useful in development of novel low molecular weight anti-TNFalpha drugs.

Etanercept (Enbrel) therapy for chronic inflammatory demyelinating polyneuropathy

Patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and/or variants who were refractory or intolerant of standard therapies were treated with etanercept, 25 mg twice per week. Ten patients underwent treatment, and manual muscle strength, sensory thresholds and functional abilities were tested prior to and 4-6 months after initiating therapy. Three patients had significant improvement and three others had possible improvement. Based on these preliminary observations, treatment with etanercept may be considered in patients with CIDP, who cannot undergo standard therapies, although its efficacy in CIDP needs to be examined in a double-blinded, controlled clinical trial.

N-Phenyl-N-purin-6-yl ureas: the design and synthesis of p38alpha MAP kinase inhibitors

The design, synthesis and SAR of a series of 2,6,9-trisubstituted purine inhibitors of p38alpha kinase is reported. Synthetic routes were devised to allow for array synthesis in which all three points of diversity could be facilely explored. The binding of this novel series to p38alpha kinase, which was predicted to have several key interactions in common with SB-203580, was confirmed by X-ray crystallography of 19 (p38 IC(50)=82 nM).

Treatment of recalcitrant psoriatic arthritis with anti-tumor necrosis factor-alpha antibody

Currently available treatments for psoriatic arthritis are either not completely effective or toxic in some patients. As tumour necrosis factor (TNF)-alpha is involved in both the joint and skin involvement in psoriatic arthritis, blockade of TNF-alpha seems a reliable way to treat patients with this disease. We report two patients with progressive recalcitrant psoriatic arthritis treated with low-dose methotrexate (7.5 mg, once per week) in combination with intravenous chimeric monoclonal anti-TNF-alpha antibody (infliximab, 3 mg/kg body weight). Both showed a dramatic and rapid response in the reduction of pain, followed by improvement of laboratory and clinical signs of joint inflammation. Skin disease also responds after a short delay. The observation shows that infliximab is effective and well tolerated in patients with recalcitrant progressive psoriatic arthritis. Different kinetics of symptom release during treatment suggest a variable role for TNF-alpha in disease pathways of pain, joint inflammation and skin involvement.

Pyridazine based inhibitors of p38 MAPK

Trisubstituted pyridazines were synthesized and evaluated as in vitro inhibitors of p38MAPK. The most active isomers were those possessing an aryl group alpha and a heteroaryl group beta relative to the nitrogen atom in the 2-position of the central pyridazine. Additionally, substitution in the 6-position of the central pyridazine with a variety of dialkylamino substituents afforded a set of inhibitors having good (p38 IC50 1-20 nM) in vitro activity.