Biomedical subjects

Edward C Keystone

Publications and source records attributed to Edward C Keystone.

24 records · Page 2Linked to original sources

PubMed2003

Anti-tumour necrosis factor agents and tuberculosis risk: mechanisms of action and clinical management.

Cases of active tuberculosis have been reported worldwide with the use of therapeutic agents that inhibit tumour necrosis factor (TNF) alpha. TNFalpha has a central role in mycobacterial infection and disease. Accordingly, progression of recently acquired tuberculosis infection or reactivation of remotely acquired infection should be expected with the use of anti-TNF agents. The available in-vitro and epidemiological evidence for the two currently approved agents, infliximab and etanercept, shows that the risk of development of active tuberculosis is greater with infliximab. Tuberculin skin testing (TST) should be undertaken before any significant immunosuppressive therapy including these agents, though the possibility of false-negative reactions in immunocompromised populations must be borne in mind. A positive TST should be followed by medical assessment and chest radiography, as well as by other tests judged appropriate by the physician to identify active disease. Active tuberculosis must be treated appropriately before initiation of treatment with an anti-TNF agent. Treatment of latent tuberculosis can be considered on an individual basis for TST-negative patients receiving anti-TNF agents when significant risk factors for infection are present.

Algorithms↗

PubMed2003

Abandoned therapies and unpublished trials in rheumatoid arthritis.

The capability of selectively targeting pathogenic elements of disease with biologic therapies has created a new therapeutic repertoire. Although a substantial number of biologic agents have been developed for treatment of rheumatoid arthritis, few have been approved for use. Most of the agents have failed to reach the approval stage because of inadequate clinical benefit. Despite this, studies of these agents have provided extremely valuable lessons in study design, immunobiology, pharmacodynamic evaluation, and the utility of animal models in the development of biologic agents. These insights have laid the groundwork for future development of other novel therapeutic agents in the treatment of rheumatoid arthritis.

Anti-Inflammatory Agents↗

PubMed2003

Therapeutic implications for interferon-alpha in arthritis: a pilot study.

OBJECTIVE: To evaluate the therapeutic potential of interferon-a (IFN-a) in osteoarthritis (OA) and rheumatoid arthritis (RA) by examining regulation of cytokine antagonist expression. METHODS: Expression of interleukin 1 receptor antagonist (IL-1Ra) and soluble tumor necrosis factor receptor (sTNFR) was examined by ELISA in cells from freshly isolated synovial fluids (SF) and synovial tissues (ST) from patients with OA or RA, either left untreated or treated with IFN-a. Single (7) and paired (5) SF and ST cells from OA and RA patients were examined. As well, the ability of IFN-a to regulate gene expression levels for osteoprotegerin (OPG) and osteoprotegerin ligand (OPGL) was examined in freshly isolated SF cells from patients with RA, by reverse transcriptase polymerase chain reaction. RESULTS: IL-1Ra and sTNFR were found to be constitutively expressed in OA and RA SF and ST cells. IFN-a treatment resulted in an increase in both IL 1Ra and sTNFR production. Freshly isolated RA SF cells exhibited constitutive OPGL gene expression in both the non-T and T cell fractions of the SF. In contrast, OPG gene expression levels were undetectable or low. IFN-a treatment of RA SF cells resulted in upregulation of OPG gene expression in the T cell fraction of the RA SF cells, whereas OPGL gene expression remained unaffected. CONCLUSION: These in vitro data suggest a therapeutic role for IFN-a in the treatment of arthritis through upregulation of critical cytokine antagonists.

Adult↗

PubMed2003

Appropriate and effective rheumatoid arthritis control: role of TNF antagonists.

There are several unmet needs for the appropriate and effective control of rheumatoid arthritis (RA), namely rapid onset of action; effectiveness in disease-modifying antirheumatic drug (DMARD)-resistant disease, including improvements in signs and symptoms, disability, quality of life and radiographic progression; sustainability of response; and a good risk/benefit ratio. Tumor necrosis factor (TNF) antagonists appear to address these needs and consequently have set a new therapeutic standard for the treatment of RA and have made it possible for rheumatologists to target remission as a primary therapeutic goal.

Arthritis, Rheumatoid↗

PubMed2002

The relationship of serum infliximab concentrations to clinical improvement in rheumatoid arthritis: results from ATTRACT, a multicenter, randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To investigate the relationship between serum concentrations of infliximab, a monoclonal anti-tumor necrosis factor alpha antibody, and clinical improvement from infliximab therapy for rheumatoid arthritis (RA). METHODS: Multiple blood samples were obtained from each of 428 subjects with active RA who were enrolled in a multicenter, randomized, double-blind, placebo-controlled trial (ATTRACT [Anti-Tumor Necrosis Factor Trial in Rheumatoid Arthritis with Concomitant Therapy]) evaluating the clinical efficacy and safety of infliximab therapy. Serum levels of infliximab were measured by enzyme-linked immunosorbent assay. Dose-response trends were analyzed using generalized logistic regression techniques. Pharmacokinetic modeling was used to predict the serum concentrations of infliximab after simulated infusions using doses and dosing intervals not evaluated in the trial. RESULTS: At week 54, 26% of the subjects receiving 3 mg/kg infliximab every 8 weeks had undetectable trough serum levels of infliximab, a significantly greater proportion than in the other 3 treatment groups (P < 0.001). Increased magnitude of American College of Rheumatology (ACR) response (measured by the ACR-N, a continuous measure of clinical improvement derived from the ACR 20% response criteria) and greater reduction from baseline in serum C-reactive protein level were both associated with higher trough serum concentrations of infliximab (P < 0.001), as was less progression of radiographic joint damage (P = 0.004), providing support for a dose-response relationship. Pharmacokinetic models predicted that decreasing the dosing interval from 8 weeks to 6 weeks would yield higher trough serum levels of infliximab than increasing the dose by 100 mg. CONCLUSION: These results suggest that some patients with RA may benefit from infliximab given at higher doses than 3 mg/kg or more frequently than every 8 weeks.

Antibodies, Monoclonal↗

PubMed2002

Etanercept versus methotrexate in patients with early rheumatoid arthritis: two-year radiographic and clinical outcomes.

OBJECTIVE: To compare the clinical and radiographic outcomes in patients with rheumatoid arthritis (RA) who received monotherapy with either etanercept or methotrexate (MTX) for 2 years and to assess the safety of this therapy. METHODS: In the Enbrel ERA (early rheumatoid arthritis) trial, 632 patients with early, active RA were randomized to receive either twice-weekly subcutaneous etanercept (10 mg or 25 mg) or weekly oral MTX (mean dosage 19 mg per week) for at least 1 year in a double-blind manner. Following the blinded phase of the trial, 512 patients continued to receive the therapy to which they had been randomized for up to 1 additional year, in an open-label manner. Radiograph readers remained blinded to treatment group assignment and the chronologic order of images. RESULTS: At 24 months, more 25-mg etanercept patients than MTX patients met American College of Rheumatology 20% improvement criteria (72% and 59%, respectively; P = 0.005), and more had no increase in total score and erosion scores on the Sharp scale (P = 0.017 and P = 0.012, respectively). The mean changes in total Sharp score and erosion score in the 25-mg etanercept group (1.3 and 0.66 units, respectively) were significantly lower than those in the MTX group (3.2 and 1.86 units, respectively; P = 0.001). Significantly more patients in the 25-mg etanercept group (55%) than in the MTX group (37%) had at least 0.5 units of improvement in the Health Assessment Questionnaire disability index (P < 0.001). Fewer patients in the etanercept group than in the MTX group experienced adverse events or discontinued treatment because of adverse events. CONCLUSION: Etanercept as monotherapy was safe and was superior to MTX in reducing disease activity, arresting structural damage, and decreasing disability over 2 years in patients with early, aggressive RA.

Adult↗