Biologics, or biologic response modifiers, may be prescribed to treat autoimmune diseases, including many types of arthritis, such as rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis. Biologics work by disrupting the inflammation process that leads to joint pain and destruction.
Types of Biologics
There are four categories of biologics: Tumor necrosis factor (TNF) inhibitors; Interleukin (IL) inhibitors; B-cells inhibitors; and T-cells inhibitors. These medications are administered with a needle, either injected under the skin or infused into a vein.
The dosing for biologics—exactly how much medication patients take, and how often— varies significantly depending on the drug and the patient. Some patients may take medication once a week, while others may take medication once every six months.
Tumor necrosis factor (TNF) inhibitors
Tumor necrosis factor is a protein produced by the immune system’s white blood cells. In healthy people, TNF triggers inflammation during a normal immune response. In people with RA, TNF triggers unnecessary inflammation that causes painful symptoms. TNF inhibitors block the activity of tumor necrosis factor, stopping the disease process.
TNF inhibitors are the most commonly used type of biologic medication. Examples of these drugs include Etanercept (Enbrel), golimumab (Simponi), infliximab (Remicade), and adalimumab (Humira).
Interleukin (IL) inhibitors
Like TNF inhibitors, Interleukin (IL) inhibitors target a type of protein involved in inflammation. These proteins are called interleukin proteins, including IL-1, IL-6, IL-12 and IL-23.
Anakinra (Kineret) blocks interleukin-1, or IL-1, that is often found in excess in patients with autoimmune diseases, such as RA. Tocilizumab (Actemra) blocks interleukin-6, or IL-6, which is found in elevated levels in people with chronic inflammatory diseases.
B-cells are small white blood cells (lymphocytes) that are integral to a body’s immune system response. Inhibiting the activity of B-cells reduces the activity of the immune system, thereby reducing RA activity. B-cell inhibitors work by targeting a protein that initiates B-cell activity. Rituximab (Rituxan) is a B-cell inhibitor.
Like B-cells, T-cells are small white blood cells that play a significant role in the immune system and inflammation. T-cell inhibitors, such as Abatacept (Orencia), blocks a protein that stimulates the overproduction of T cells.
Biologics have the potential to stop the inflammatory disease process. However, they also have various potential side effects and increase a person’s risk of infection. They also tend to be expensive. Because of these potential downsides, biologics are used when methotrexate or other DMARDs prove insufficient or cause unacceptable side effects.
Testing for Tuberculosis and Other Infections
Before taking any type of biologic medication, a person must be tested for tuberculosis. People who have latent tuberculosis carry the Mycobacterium tuberculosis bacterium without having tuberculosis symptoms. If a person with latent tuberculosis takes immune-suppressing biologic medications, the bacterium can multiply and cause symptomatic tuberculosis.
In addition to being screened for tuberculosis, patients are usually screened for other types of chronic infections, including hepatitis.