Arthritis: Reports from 2003 Arthritis Meeting (cont.)
Enbrel is an injectable blocker of tumor necrosis factor for treating rheumatoid arthritis and psoriatic arthritis. Tumor necrosis factor (TNF) is a protein that the body produces during the inflammatory response, which is the body's reaction to injury. TNF promotes the inflammation and its associated fever and signs (pain, tenderness, and swelling) in several inflammatory conditions, including rheumatoid arthritis. Enbrel is a synthetic (man-made) protein that binds to TNF. Enbrel thereby acts like a sponge to remove most of the TNF molecules from the joints and blood. This prevents TNF from promoting inflammation and the fever, pain, tenderness, and swelling of joints in patients with rheumatoid arthritis (and apparently other forms of inflammatory arthritis, such as psoriatic arthritis, ankylosing spondylitis, and juvenile arthritis-see below). Enbrel is given by subcutaneous injection with a needle and syringe twice weekly.
Enbrel was found to be effective in a once weekly, 50 mg, dose!
Dr. Shiel's Perspective: This is big news. Enbrel is now given by two 25 mg doses each week. Look for once weekly 50 mg dosing soon. Obviously, far more convenient for patients using Enbrel.
Several reports noted the safety and effectiveness of Enbrel for treating patients with psoriatic arthritis.
Dr. Shiel's Perspective: Enbrel has been granted FDA approval for psoriatic arthritis this year because of previous reports that had similar results.
Enbrel was reported effective in treating ankylosing spondylitis.
Dr. Shiel's Perspective: Look for FDA approval for this purpose soon.
Researchers from the United Kingdom reported that patients whose rheumatoid arthritis is not controlled with Remicade can respond successfully to Enbrel.
Dr. Shiel's Perspective: Well this is very interesting. Since both Remicade and Enbrel block TNF as a key method of action, one might expect that switching from one drug to the other might not be effective. Wrong. The researchers point out that the reason for the benefit from switching might be related to the fact that they do differ slightly in their targets (Remicade binds to both a soluble form of TNF-alpha and to TNF-alpha bound to membranes of cells, while Enbrel binds to soluble TNF-alpha and to another chemical messenger lymphotoxin-alpha). Big words! They simply mean that if one fails on one TNF-blocking drug, it is rational to try another.
Enbrel for rheumatoid arthritis was reported to have sustained benefit and safety after 5 years of treatment.
Dr. Shiel's Perspective: Great news to have long-term data that supports the concept that this drug actually safely stops rheumatoid arthritis in its tracks!