How well does adalimumab work to treat rheumatoid arthritis and how safe is it?
To answer this question, scientists analyzed six high quality studies. The studies tested over 2300 people who had rheumatoid arthritis for more than 10 years. People had either injections of adalimumab or fake injections. Some studies also tested people taking methotrexate in combination with adalimumab or the fake injections. This Cochrane Review provides the best evidence we have today.
What is rheumatoid arthritis and how can adalimumab help?
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 affected joints. Adalimumab is a "biologic" that is injected into the body to decrease pain and swelling and slow the progress of rheumatoid arthritis. Adalimumab is a new drug that was approved for injection at a dose of 40 mg every other week. It is usually prescribed when other disease modifying anti-rheumatic drugs (DMARDs) do not work well.
How well did adalimumab work?
More people improved with all doses of adalimumab plus methotrexate than with fake injections plus methotrexate. After 24 weeks:
- 43 out of 100 people showed a 50% improvement with 40 mg of adalimumab every other week plus methotrexate
- 9 out of 100 people showed a 50% improvement with fake injections plus methotrexate
This means that 34 more people out of 100 benefited from receiving adalimumab plus methotrexate than fake injections plus methotrexate.
More people had improved symptoms with adalimumab alone than with fake injections, but the improvement was not at much as when adalimumab was taken in combination with methotrexate.
After 52 weeks, x-rays showed that 20 mg of adalimumab every week or 40 mg every other week slowed joint damage more than fake injections.
Were there any side effects?
Minor side effects included reactions where the needle was injected, headaches, allergy-like symptoms, and colds. Some people went to hospital because of serious side effects. Most side effects occurred about the same amount for people taking adalimumab and people taking fake injections.
- 5 out of 100 people had serious side effects with 40 mg of adalimumab every other week plus methotrexate
- 7 out of 100 people had serious side effects with fake injections plus methotrexate
This means that 2 more people out of 100 had a serious side effect from receiving fake injections plus methotrexate than adalimumab plus methotrexate.
One study showed that people who received adalimumab had more serious infections such as tuberculosis and cancer than people who took fake injections. Long-term side effects still need to be studied.
What is the bottom line?
There is "Gold" level evidence (www.cochranemsk.org) that in people with long-standing rheumatoid arthritis who do not respond to DMARDs, adalimumab at 40 mg every other week plus methotrexate decreases pain and swelling.