An Overview of Enbrel (etanercept)

Enbrel (etanercept) is a biologic response modifier (a recombinant human soluble tumor necrosis factor receptor fusion protein). Enbrel is genetically engineered to be like the receptors in the body that bind to tumor necrosis factor (TNF-alpha). Enbrel works by soaking up excess TNF before it can attach to natural receptors.

TNF-alpha is a cytokine involved in the inflammatory process. Excess TNF-alpha has been associated with rheumatoid arthritis and other forms of inflammatory arthritis.

Enbrel was the first anti-TNF drug and was approved in 1998 for rheumatoid arthritis and certain inflammatory types of arthritis. Remicade (infliximab) was the second TNF inhibitor to be approved by the U.S. Food and Drug Administration in 1999. Humira (adalimumab) was approved in 2002. Simponi (golimumab) was approved by the FDA on April 24, 2009. Cimzia (certolizumab pegol) was FDA-approved on May 14, 2009.

Enbrel is derived by introducing human DNA into Chinese hamster ovary cells and creating a genetically engineered protein. Remicade uses human and mouse proteins to create a chimeric monoclonal antibody. Humira uses fully human proteins and phage display technology to produce monoclonal antibodies.

Enbrel is administered as a subcutaneous injection once or twice weekly (3 or 4 days apart). The dosage prescribed depends on the condition being treated. Enbrel must be prescribed by your doctor and requires insurance pre-authorization. Enbrel can be used in combination with methotrexate in patients who do not respond to methotrexate alone.

Enbrel has been approved to treat moderate to severe rheumatoid arthritis, moderate to severe juvenile rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, chronic moderate to severe plaque psoriasis.

For adults with rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis, the usual dose of Enbrel is 50 mg per week administered as a subcutaneous injection using a 50 mg/ml single-use prefilled syringe. There are 25 mg vials of Enbrel which are also available.

The dosage of Enbrel prescribed for juvenile rheumatoid arthritis is based on the child's weight. A once-weekly dosing option exists for children weighing 138 lbs or more. For plaque psoriasis, the usual dose is 50 mg twice a week for 3 months, stepped down to once weekly.

Enbrel is not recommended for pregnant or nursing women. Patients with serious infections should not be treated with Enbrel. People prone to infection or those with uncontrolled diabetes should not use Enbrel. Patients with certain conditions of the central nervous system should also avoid Enbrel.

Common side effects associated with Enbrel include:

• injection site reactions
• upper respiratory infections, including sinus infections
• headaches
• dizziness
• runny nose
• throat irritation

Enbrel may increase the risk of serious infections. In people who are treated with Enbrel, there have been reports of multiple sclerosis, myelitis (inflammation of spinal cord), optic neuritis (inflammation of optic nerve), and pancytopenia (low numbers of red cells, white cells, platelets).

Enbrel should be stored at a temperature of 36 to 46 degrees Fahrenheit. However, Enbrel can be kept at room temperature for up to 14 days. Enbrel should never be stored in the freezer.

According to enbrel.com, if traveling for more than a few hours, you should wrap Enbrel in bubble wrap and place it in a travel cooler packed with ice. Add a thermometer to the cooler and check it every few hours. You can obtain a free travel cooler and ice pack for Enbrel by calling Enbrel Support at 1-888-4ENBREL. If traveling by air, check with the airline for their requirements.