Etanercept for the treatment of rheumatoid arthritis.

BACKGROUND

Etanercept is a soluble tumour necrosis factor alpha-receptor DMARD for the treatment of rheumatoid arthritis (RA).

OBJECTIVES

To assess the efficacy and safety of etanercept for the treatment of RA.

SEARCH STRATEGY

Five electronic databases were searched from 1966 to February 2003 with no language restriction.

SELECTION CRITERIA

All randomized controlled trials (minimum 6 month duration) comparing three possible combinations 1) etanercept (10 mg or 25 mg twice weekly) with methotrexate (MTX) to MTX alone 2) etanercept to MTX, or 3) etanercept to placebo were eligible.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data and assessed the methodological quality of the trails. The American College of Rheumatology (ACR) core set of disease activity measures for RA clinical trials, radiographic, withdrawals and toxicity outcomes were analyzed.

MAIN RESULTS

Three trials were included in this review. Two trials compared an experimental group who were started on etanercept compared to a control group; both groups had the same ongoing background therapy of nonsteroidals in both trials plus in one trial one group was on stable methotrexate. In these two trials the ACR 20, ACR 50 and ACR 70 response rates at 6 months were statistically significantly and clinically important with etanercept 25 mg subcutaneous injections (SC) twice weekly. Sixty-four percent of people receiving etanercept ache vied an ACR 20 response compared to 15% of controls and the number needed to treat (NNT) with etanercept is 2 people. Thirty-nine percent of those receiving etanercept achieved an ACR 50 response compared to 4% of taking control treatment and the NNT is three. Fifteen percent of people taking etanercept achieved an ACR 70 compared to 1% of controls with a NNT of 7 people. In the third trial of starting etanercept compared to starting methotrexate the number of participants who achieved an ACR 20, 50 or response at 6 and 12 months were not statistically significant for either etanercept dose. Etanercept treatment showed a statistically significantly and clinically important affect on joint damage as measured by the Sharp erosion score. Among participants who received etanercept 72% had no increase in their erosion score compared to 60% of participants in the methotrexate group. Withdrawal and toxicity results were acceptable.

REVIEWER'S CONCLUSIONS: Etanercept 25 mg SC twice weekly was more efficacious than control treatment for ACR 20, 50 and 70 at 6 months, and over 12 months it slowed joint damage.