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Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterised by infiltration of immune cells into the affected synovium, release of inflammatory cytokines and degradative mediators, and subsequent joint damage. Both innate and adaptive arms of the immune response play a role, with activation of immune cells leading to dysregulated expression of inflammatory cytokines. Cytokines work within a complex regulatory network in RA, signalling through different intracellular kinase pathways to modulate recruitment, activation and function of immune cells and other leukocytes. As our understanding of RA has advanced, intracellular signalling pathways such as Janus kinase (JAK) pathways have emerged as key hubs in the cytokine network and, therefore, important as therapeutic targets. Tofacitinib is an oral JAK inhibitor for the treatment of RA. Tofacitinib is a targeted small molecule, and an innovative advance in RA therapy, which modulates cytokines critical to the progression of immune and inflammatory responses. Herein we describe the mechanism of action of tofacitinib and the impact of JAK inhibition on the immune and inflammatory responses in RA.

Background: Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis. Here, tofacitinib safety and efficacy data from a long-term extension study in Japanese patients are presented., Methods: Study A3921041 was a multi-centre, open-label, long-term extension study that included Japanese patients who had participated in a prior Phase 2 or Phase 3 study of tofacitinib as monotherapy or with background methotrexate. Patients received tofacitinib 5 mg twice daily (BID) or tofacitinib 10 mg BID. Dose adjustment of tofacitinib during treatment period, and concomitant usage of disease-modifying antirheumatic drugs including methotrexate after week 12 were permitted. Primary endpoints were adverse events, laboratory parameters and vital signs. Secondary efficacy endpoints included American College of Rheumatology (ACR)20/50/70 response rates, Disease Activity Score (DAS)28-4(erythrocyte sedimentation rate (ESR))<2.6 response rate (DAS-defined remission) and Health Assessment Questionnaire-Disability Index (HAQ-DI) score. Safety and efficacy data were assessed throughout the study., Results: A total of 486 patients were recruited and treated (1439.9 patient-years of exposure). 308 patients completed the study. Median (range) duration of treatment in this extension study was 1185 (5-2016) days. 476 patients (97.9 %) experienced adverse events; the majority of which (97.8 %) were of mild or moderate severity. The two most common treatment-emergent adverse events were nasopharyngitis (n = 293, 60.3 %) and herpes zoster (n = 94, 19.3 %). For all tofacitinib-treated patients, the incidence rate (patients with events per 100 patient-years) was 10.7 for serious adverse events, 3.3 for serious infections, 7.4 for herpes zoster (serious and non-serious) and 1.2 for malignancies (excluding non-melanoma skin cancer). Mean changes from baseline (start of the index study) in laboratory parameters were consistent with those seen in previously reported studies of tofacitinib. ACR20/50/70 response rates, DAS-defined remission rates and HAQ-DI scores were sustained through to study completion., Conclusions: Tofacitinib (with or without background methotrexate) demonstrated a stable safety profile and sustained efficacy in Japanese patients with active rheumatoid arthritis. The risk of herpes zoster appears to be higher in Japanese patients treated with tofacitinib than in the global population., Trial Registration: Clinicaltrials.gov NCT00661661 . Registered 7 February 2008.

Objectives: To evaluate oral tofacitinib versus placebo for treatment of active rheumatoid arthritis in Japanese patients with inadequate response to disease-modifying antirheumatic drugs., Methods: In this double-blind, placebo-controlled, randomized, parallel-group, 12-week, phase 2 study (clinicaltrials.gov NCT00687193), 317 patients received tofacitinib: 1, 3, 5, 10, or 15 mg as monotherapy or placebo twice daily (BID)., Primary Endpoint: response rate by American College of Rheumatology (ACR) ≥ 20% improvement criteria (ACR20) at week 12., Results: ACR20 response rates: 37.7% (20/53), 67.9% (36/53), 73.1% (38/52), 84.9% (45/53), and 90.7% (49/54) with tofacitinib: 1, 3, 5, 10, and 15 mg BID, respectively, versus 15.4% (8/52) with placebo (p < 0.01; all doses). Dose-dependent ACR20 responses with tofacitinib versus placebo occurred from week 2 onward (p < 0.05). Changes from baseline in 28-joint disease activity score using erythrocyte sedimentation rate improved with tofacitinib versus placebo from week 4 (p < 0.01; all doses). Six tofacitinib patients experienced treatment-related serious adverse events (AEs). Most common treatment-emergent AEs: nasopharyngitis (10% vs 12%) and hyperlipidemia (5% vs 0%). Serum creatinine, hemoglobin, and total-, low-, and high-density lipoprotein-cholesterol levels increased with tofacitinib., Conclusions: Tofacitinib produced dose-dependent ACR20 responses and reduced disease activity. The safety profile was consistent with that reported from global monotherapy trials.

Introduction: CP-690550 is a small molecule inhibitor of Janus kinase 3 (JAK3), a critical enzyme in the signaling pathway of multiple cytokines (interleukin (IL)-2, -7, -15 and -21) that are important in various T cell functions including development, activation and homeostasis. The purpose of this study was to evaluate CP-690550 in murine collagen-induced (CIA) and rat adjuvant-induced (AA) models of rheumatoid arthritis (RA)., Methods: CIA and AA were induced using standard protocols and animals received the JAK3 inhibitor via osmotic mini-pump infusion at doses ranging from 1.5-15 mg/kg/day following disease induction. Arthritis was assessed by clinical scores in the CIA models and paw swelling monitored using a plethysmometer in the AA model until study conclusion, at which time animals were killed and evaluated histologically., Results: CP-690550 dose-dependently decreased endpoints of disease in both RA models with greater than 90% reduction observed at the highest administered dose. An approximate ED50 of approximately 1.5 mg/kg/day was determined for the compound based upon disease endpoints in both RA models examined and corresponds to CP-690550 serum levels of 5.8 ng/ml in mice (day 28) and 24 ng/ml in rats (day 24). The compound also reduced inflammatory cell influx and joint damage as measured histologically. Animals receiving a CP-690550 dose of 15 mg/k/d showed no histological evidence of disease., Conclusion: The efficacy observed with CP-690550 in CIA and AA suggests JAK3 inhibition may represent a novel therapeutic target for the treatment of RA.

Objective: To evaluate the efficacy and safety of celecoxib in patients with ankylosing spondylitis (AS)., Methods: This was a 12-week randomized, double-blind, placebo-controlled study with 4 treatment arms: celecoxib 200 mg qd, celecoxib 400 mg qd, naproxen 500 mg bid, and placebo. Patients (age 18-75 yrs) requiring daily treatment with nonselective nonsteroidal antiinflammatory drugs, and with a pain intensity on visual analog scale (VAS) > or = 50 mm worsening by 30% compared with a preinclusion visit (14 days prior) were studied. Primary endpoints were least-squares mean changes from baseline in pain intensity, disease activity (patient global assessment VAS), and functional impairment [Bath Ankylosing Spondylitis Functional Index (BASFI)]. Adverse events were monitored throughout the study., Results: Of 611 randomized patients, 137 were allocated to celecoxib 200 mg, 161 to celecoxib 400 mg, 157 to naproxen, and 156 to placebo. Improvements in least-squares mean pain intensity, disease activity, and BASFI scores were significantly greater in the celecoxib 200 mg, celecoxib 400 mg, and naproxen groups than in the placebo group (p < or = 0.001) at Week 12 and the interim timepoints, Weeks 1, 3, and 6. Celecoxib 400 mg was as effective as naproxen; however, naproxen was more effective than celecoxib 200 mg. Celecoxib was well tolerated, with an adverse event profile similar to placebo. However, 3 naproxen-treated patients experienced serious treatment-related gastrointestinal (GI) adverse events (one severe gastric ulcer, one moderate GI hemorrhage, one severe GI hemorrhage)., Conclusion: In this 12-week study, celecoxib 200 mg qd and 400 mg qd were efficacious and well tolerated in treating signs and symptoms of AS.

Objective: Although total joint arthroplasty (TJA) is a common procedure and an important outcome in rheumatoid arthritis (RA), little is known about its prevalence, failure rate, or predictors over the course of the illness. The current study evaluated these factors in 1,600 consecutive RA patients seen during a period of observation that extended 23 years., Methods: Beginning in 1974, data from 34,040 RA patient visits were entered prospectively into a computer databank. Data consisted of laboratory, radiographic, physical examination, and self-report questionnaires. At each assessment, we also noted a complete surgical history. Patients were also followed up by questionnaires that were mailed at 6-month intervals., Results: Kaplan-Meier life-table estimates indicated that 25% of RA patients will undergo total joint arthroplasty (TJA) within 21.8 years of disease onset. For patients with 1 TJA, 25% had a TJA in a different joint within 0.92 years and 50% within 7.0 years. Ten years after TJA, approximately 6% of implanted knees and 4% of implanted hips had been replaced with a second TJA, and 12% and 13% of the joints had either a second TJA or a TJA-related operation, respectively. In Cox regressions, a large series of clinical and laboratory variables, which primarily reflected disease activity, predicted TJA. Smoking, either past or present, had a protective effect. Patients with highly abnormal values on the Health Assessment Questionnaire Disability Scale, global severity, and erythrocyte sedimentation rate had a 3-6 times increased risk of TJA., Conclusion: TJA, a marker of joint failure and of RA outcome, is predicted by self-report assessments of severity and function, and by a series of laboratory, radiographic, and clinical variables. Prediction improves with the extent of observation, and 2-year observations approach full-study observations in their accuracy. Most TJAs survive for a long time in RA.

Objective: To study the clinical presentation, immunogenetics, and serum immune response to lipopolysaccharide (LPS) in a cohort of patients with post-Salmonella reactive arthritis (ReA)., Methods: A validate ReA screening questionnaire (Quest 2) was mailed to 919 individuals reporting symptoms of gastroenteritis to the health department after eating at a single restaurant. Three hundred twenty-one persons returned questionnaires; 170 reported symptoms outside the gastrointestinal tract; 23 of those 170 reporting persistent joint symptoms were seen 4 to 16 weeks after the outbreak and 5 of the 23 were seen in followup 12 to 20 weeks later. Clinical features, HLA Class I typing, serum soluble CD8 levels, and serum antibodies to gram negative LPS by ELISA were determined., Results: Joint complaints were reported more frequently by individuals with a longer duration of diarrhea. Upper extremity joints were frequently involved, and 66% reported one or more extraarticular symptoms of Reiter's syndrome. Three of 5 typed individuals were HLA-B27 positive, including 3 of the 4 most severely involved. Serum soluble CD8 levels correlated poorly with disease activity measured either clinically or by C-reactive protein. Antibodies to Klebsiella and Shigella LPS rose over time, while antibodies to Salmonella LPS fell., Conclusion: The clinical picture of post-Salmonella ReA is less stereotyped than often assumed, although severity correlated with HLA-B27 status. The association of joint symptoms with duration of diarrhea and the kinetics of the anti-LPS antibody response support the hypothesis that abnormal gut permeability plays a role in the pathogenesis of post-Salmonella ReA.

Synovial tissue is rarely available from patients with early synovitis, with the exception of synovial biopsies. However, T cell populations early in the development of synovitis may be enriched in antigen-specific cells and critical to disease pathogenesis. To investigate the T cell repertoire in early synovitis, we utilized a PCR protocol for detection of T cell receptor (TCR) transcripts present in small amounts of synovial tissue. To expand the substrate for PCR, preamplification of cDNA was performed with a 3' constant region primer plus either a mixture of variable region primers or random hexanucleotides. Utilizing this method improved the sensitivity of detection. This technique is applied here to the analysis of TCR transcripts in synovial biopsies from individuals with early rheumatoid arthritis (RA) and non-RA synovitis. TCR alpha-chain transcripts were detectable in 5/5 RA and 4/4 non-RA specimens evaluated, with beta-chain transcripts detected in 4/5 early RA and 4/4 non-RA specimens evaluated. Confirmation of transcripts by sequencing of cloned PCR products verified the specificity of amplification. The most frequently expressed TCR V region families in early RA synovitis were V alpha 11, V alpha 14, V alpha 28, V beta 7, V beta 9 and V beta 17. Several of these V regions have previously been implicated in studies of chronic RA synovitis. J alpha and J beta region usage was similar to that seen in chronic RA, and conserved N region motifs were apparent. We conclude that it is possible to detect TCR transcripts in small synovial biopsies from individuals with early arthritis.(ABSTRACT TRUNCATED AT 250 WORDS)

Objective: To test the safety and efficacy of olsalazine in men with ankylosing spondylitis (AS) unresponsive to nonsteroidal antiinflammatory drugs and physiotherapy., Methods: Four patients, including 2 who had not responded to sulfasalazine (SASP) and one who did not tolerate SASP, were treated with olsalazine, up to 3 g/dl for 24 weeks., Results: One patient discontinued olsalazine due to diarrhea at 1 g/day. The other 3 experienced improvement in global spine self assessment by visual analog scale (VAS), 2 of 3 patients, spinal pain (VAS, 3 of 3), night pain (3 of 3), tender joint count (3 of 3) and enthesis score (3 of 3). Changes in Schober's test and chest expansion were minor. Erythrocyte sedimentation rate and C-reactive protein were normal. Loose stools were the only adverse effects observed., Conclusion: Olsalazine appears to be well tolerated and effective in men with AS. Further study of olsalazine and direct comparison with SASP in this population may illuminate mechanisms of drug action and add a new therapeutic option.

While many investigators have examined V gene usage by the clonotypic T-cell receptor (TCR) in rheumatoid arthritis (RA) joints, few have reported on arthritic controls. We compared TCR alpha-chain V gene usage in knee synovial tissue specimens from 9 RA and 5 osteoarthritis (OA) patients. There was no significant difference in the number of V gene families used in RA compared with OA synovium. However, there was an increased prevalence of V alpha 28, V alpha 10, V alpha 17, and V alpha 18 and under representation of V alpha 15 in RA compared with OA synovium. Of these, V alpha 28 was also recently described by us as being present in RA synovial tissue early in the course of disease. V alpha 28 associated J region usage, and N-regional diversity was surveyed in T-cell receptors from additional rheumatoid synovial tissue T-cell populations and normal peripheral blood. Oligoclonality was observed in 6/10 rheumatoid specimens either by direct sequencing or where three or more molecular clones were sequenced, compared with 0/5 normal PBMCs. The oligoclonal populations included 2/3 cell lines stimulated with interleukin-2 (IL-2) alone. Several novel J regions were observed, with some recurrent residues observed at N-region positions. These data indicate an increased prevalence of certain TCR V region families in RA versus OA synovium, and suggest an antigen-driven expansion of V alpha 28-expressing T cells in RA synovium.