Enbrel is the trade name for Etanercept, a medication used for treating autoimmune diseases. Enbrel is a TNF (tumor necrosis factor) inhibitor; it interferes with TNF. TNF is made by the body's immune system; it encourages an inflammatory response, causing many of the clinical problems linked to autoimmune diseases, such as rheumatoid arthritis, ankylosing spondylitis, Crohn's disease, psoriasis and refractory asthma. People with these immune disorders have too much TNF in their bodies.
Etanercept is a fusion protein (chimeric protein) - it is created through the joining of two or more genes which originally coded for separate proteins, i.e. it is a protein made from a fusion gene, which is created by fusing (joining) parts of two different genes.
Etanercept is co-marketed in North America by Wyeth and Amgen, under the trade name Enbrel. There are two separate formulations:
A lyophilized (freeze-dried) powder in 25 mg vials. The powder needs to be reconstituted with a diluting agent (diluents) and then injected subcutaneously (the needle is inserted just under the skin). Most patients can be taught to do this themselves.
A pre-mixed liquid - some arthritis patients found the reconstitution procedure difficult. So, pre-filled 50mg/ml syringes were made available in 2004. In 2006 auto-injector 'pens' became available.
In Japan Enbrel is marketed by Takeda Pharmaceuticals. In the rest of the world it is marketed solely by Wyeth.
Enbrel cannot be swallowed, because the digestive system would destroy the medication.
What does Enbrel treat?
In the United States, Enbrel has been licensed by the Food and Drug Administration (FDA) for the treatment of:
Ankylosing Spondylitis (AS) - a chronic (long-term), painful and progressive inflammatory disease affecting joints and ligaments that normally allow a person's back to move and flex. It affects up to half a million people in the United States. The disease most often occurs in the lower back, but can affect the upper spine, chest and neck.
In more advanced disease, the spine can fuse, causing loss of motion and a permanent stooped-over posture. AS may also involve other joints, such as the hips, shoulders, knees and ankles. Unlike other forms of arthritis, AS frequently affects individuals between the ages of 17 and 35. It tends to affect more men than women.
Moderate to Severe Plaque Psoriasis (psoriasis vulgaris) - about 80% to 90% of people with psoriasis have this type. Signs and symptoms include raised areas of inflamed skin covered with silvery white scaly skin (plaques). A flaky white build up of dead skin cells accumulates on the plaques; this is called scale. Plaque psoriasis can appear on any skin surface.
Most commonly affected areas are the knees, scalp, trunk, nails and elbows. This scale becomes dislodged and sheds from the plaques. Affected areas of skin are usually extremely dry, itchy. Sometimes there is pain and cracking of the skin. Psoriasis vulgaris means "common psoriasis".
Moderate to severe polyarticular juvenile idiopathic arthritis (juvenile rheumatoid arthritis) - the most common chronic rheumatic disease in children and a major cause of short-term and long-term disability. Polyarticular juvenile idiopathic arthritis causes chronic pain, stiffness and swelling of the joints. In severe cases there may be joint damage and deformities.
The disease usually starts before the age of 16 years and affects approximately 1 in every 1,000 American children.
Moderate to severe rheumatoid arthritis (rheumatoid disease) - a chronic (long lasting), progressive and disabling auto-immune disease condition that causes inflammation (swelling) and pain in the joints, the tissue around the joints, and other organs in the human body.
Rheumatoid arthritis usually affects the joints in the hands and feet first, but any joint may become affected. Patients with rheumatoid arthritis commonly have stiff joints and feel generally unwell and tired.
Psoriatic arthritis - a chronic (long-term) disease, is a form of inflammatory arthritis that affects between 10% and 30% of patients who have psoriasis (National Psoriasis Foundation, USA). The majority of patients with psoriatic arthritis developed the skin conditions - psoriasis - first, and were later diagnosed with psoriatic arthritis. However, in about 20% of cases arthritis symptoms may emerge beforehand. If the arthritis symptoms emerge many years before the skin symptoms an accurate diagnosis may be difficult. Some patients may just have psoriasis symptoms for a couple of decades before the development of arthritis.
People with psoriatic arthritis have inflammation of the skin (psoriasis) and joints (arthritis). Psoriatic arthritis may emerge at any time, but it most commonly appears between the ages of 30 and 50 years. The risk of developing the condition is slightly higher for males than females.
Unlike most other drugs that are usually small molecules synthesized using the tools of organic chemistry discovered through empirical testing (information gained by means of observation, experience, or experiment), etanercept is a protein-based drug that was created using the biotechnology tools and conceived through an understanding provided by cell biology.
More about TNF (tumor necrosis factor), TNF receptors, and TNF inhibitors
TNFa (tumor necrosis factor-alpha) is a cytokine produced by monocytes and macrophages.
What is a cytokine? A substance (of which there are many) that is secreted by specific immune system cells which carry signals locally between cells. Consequently, it has an effect on other cells.
What is a monocyte? A type of white blood cell which forms part of the human body's immune system.
What are macrophages? These are white blood cells within tissues. They also form part of the human body's immune system. Macrophages are produced by the division of monocytes.
TNFa regulates a body's immune response by increasing the transport of white blood cells to areas of inflammation, and also through other molecular mechanisms which trigger and intensify inflammation.
In other words, as part of the body's inflammatory response, TNFa can trigger and exacerbate an inflammation (make inflammation worse).
Etanercept, a TNF inhibitor, reduces the body's inflammatory response by inhibiting the action of TNFa. This is especially useful when treating autoimmune diseases.
There are two types of TNF receptors:
Receptors which are embedded in white blood cells - they respond to TNF by releasing other cytokines; i.e. these cause inflammation.
Soluble TNF receptors - these deactivate TNF and inhibit the immune response; i.e. these reduce inflammation.
Etanercept imitates the effects of the naturally occurring soluble TNF receptors. However, as TNF is a fusion protein, rather than a simple TNF receptor, it has a much longer half-life in the bloodstream. In other words, etanercept has a longer-lasting effect in the bloodstream than the naturally occurring soluble TNF receptors.
Important information about taking prescription ENBREL
While Enbrel can reduce the amount of TNF in the body, thus reducing the damage that too much TNF may cause, the medication may also lower the patient's immune system's ability to fight infections. Patients taking Enbrel have a higher risk of getting infections, as well as a risk of infections becoming worse. For more information, go to Important Safety Information (half-way down the page).
Written by
View drug information on Enbrel.
Комментариев нет:
Отправить комментарий