Etanercept for the treatment of rheumatoid arthritis

Blumenauer BBTB, Cranney A, Burls A, Coyle D, Hochberg MC, Tugwell P, Wells GA

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Summary

Etanercept for the treatment of rheumatoid arthritis

HOW WELL DOES ETANERCEPT (ENBREL) WORK TO TREAT RHEUMATOID ARTHRITIS AND HOW SAFE IS IT?

To answer this question, scientists analysed 3 high quality studies. The studies tested over 900 people who had rheumatoid arthritis. People had either injections of etanercept at 10 mg to 25 mg two times a week, methotrexate (MTX) (pills or injections) or placebo injections. This Cochrane Review provides the best evidence we have today.

What is etanercept (Enbrel) and why is it prescribed?
Rheumatoid arthritis is a disease in which the body's immune system attacks its own healthy tissues. The attack happens mostly in the joints of the feet and hands and causes redness, pain, swelling and heat around the joint. Etanercept (Enbrel) is a "biologic" that is prescribed to decrease pain and swelling and slow the progress of rheumatoid arthritis. It is usually prescribed when other DMARDs (disease modifying antirheumatic drugs) do not work well, but can be expensive.

How well does it work?
After 6 months of treatment, a 50% improvement in symptoms occurred in 4 out of 100 people taking MTX or a placebo compared to 39 out of 100 people taking etanercept with or without MTX. This occurred in people with long standing rheumatoid arthritis in whom DMARDs (disease modifying anti-rheumatic drugs) were not working.

After 12 months of treatment, about the same number of people with newly diagnosed rheumatoid arthritis improved with etanercept injections or MTX pills. But etanercept slowed joint damage more than MTX: joint damage slowed in 72 out of 100 people taking etanercept compared to 60 out of 100 people taking MTX.

How safe is it?
Side effects such as headache, common colds, nausea, dizziness, weakness, stomach upset, mouth ulcers and reactions at the site of the injection may occur. But the number of people who stopped taking etanercept due to side effects was the same or less than the number who stopped taking MTX or the placebo. Long term side effects, such as infections like tuberculosis, and cancer still need to be studied.

What is the bottom line?
There is "Gold" level evidence that in people with long standing rheumatoid arthritis in whom DMARDs (disease modifying anti-rheumatic drugs) are not working, injections of etanercept at 25 mg two times a week for 6 months with or without methotrexate decreases pain and swelling better than metotrexate alone or no DMARDs.

In people newly diagnosed with rheumatoid arthritis, injections of etanercept at 25 mg two times a week for 12 months works just as well as methotrexate pills and slows damage to the joints more than methotrexate.

Etanercept is safe and side effects are well-tolerated. Rare and long-term side effects are not yet known.

This is a Cochrane review abstract and plain language summary, prepared and maintained by The Cochrane Collaboration, currently published in The Cochrane Database of Systematic Reviews 2010 Issue 1, Copyright © 2010 The Cochrane Collaboration. Published by John Wiley and Sons, Ltd.. The full text of the review is available in The Cochrane Library (ISSN 1464-780X).
This record should be cited as: Blumenauer BBTB, Cranney A, Burls A, Coyle D, Hochberg MC, Tugwell P, Wells GA. Etanercept for the treatment of rheumatoid arthritis. Cochrane Database of Systematic Reviews 2003, Issue 3. Art. No.: CD004525. DOI: 10.1002/14651858.CD004525.

This version first published online: October 20. 2003

Abstract

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.

Authors' 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.

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