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.