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Biologic Medications for Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory arthritis that commonly affects the spine, although other joints in the body may also be affected. AS causes pain and stiffness, and as the condition progresses, the joints may fuse, causing lack of flexibility and mobility. While there is no cure for AS, treatments can help reduce the symptoms and may help slow the progression, helping people with AS improve or maintain their quality of life.

The basics of biologics

Biologic medications are a type of therapy that may be used to treat certain people with AS. Biologics are commonly used after initial treatment with non-steroidal anti-inflammatory drugs (NSAIDs) have been tried and haven’t provided sufficient relief from symptoms, or for people who cannot tolerate NSAIDs due to side effects. Biologics are also typically used in people with AS who have evidence of joint damage visible on imaging (radiographic axial spondylitis).1

Biologic therapies are complex molecules made from living organisms, and the sources used may be human, animal, bacteria, or yeast. They are designed to target specific aspects of the inflammatory process.2 This targeted approach helps biologics to be very effective with minimal, if any, side effects.

What are the biologic therapies approved to treat ankylosing spondylitis?

Currently, there are several biologic therapies approved to treat AS, including:

Most of the above biologic therapies are tumor necrosis factor (TNF) inhibitors, or TNF blockers. Consentyx is different, though. It is an interleukin 17-A (IL-17A) blocker.

Which biologic is the best for treating ankylosing spondylitis?

Each individual responds differently to medications, and what works for one person may not be the best for someone else. Some people with AS may have to try more than one biologic therapy to find the best treatment for their symptoms or to find a treatment that they can tolerate.

How do biologic medications work?

The active ingredients in biologic therapies are organic substances that are engineered and grown in a laboratory. These medicines work by targeting and affecting specific proteins and substances (TNF or IL-17A) that are involved in the inflammatory process.

The inflammatory process is an important part of the body’s immune system. When the immune system senses the presence of an infection or other problem, it triggers the process of inflammation in order to fight off the infection. People with AS have immune systems that cause too much inflammation in the joints, and the chronic inflammation can damage the joints, causing pain, stiffness, or fused joints. Biologics work by specifically targeting and reducing the amount of inflammation to help relieve a person’s symptoms.

The inflammatory response

TNF, or tumor necrosis factor, is a naturally occurring protein, called a cytokine, that is involved in the normal inflammatory response in the body. In people with AS, there is an elevated level of TNF. TNF inhibitors, also called TNF blockers, interrupt this inflammatory process and help reduce symptoms of AS.2

IL-17A is another protein which is involved in the inflammatory response. While IL-17A proteins occur naturally in the body, in people with conditions like AS, there is an excess or abnormal amount of inflammation and increased levels of IL-17A. IL-17A blockers target this pathway, blocking the IL-17A protein from connecting to the IL-17A receptor and stopping the cascade of inflammation that occurs from this pathway. Blocking one of the inflammatory pathways can help reduce the symptoms of AS like pain and stiffness in the joints.2

What are the risks or common side effects with biologic medications?

Because biologic medications interfere with the proteins involved in the immune system function, they may impair your body’s ability to fight infections. Some people taking biologic medications have experienced serious infections, including tuberculosis (TB), bacterial sepsis, and invasive fungal infections, viral infections, or other opportunistic infections. Some serious infections may lead to hospitalization or death.

Other common side effects from biologic medications include upper respiratory infections and reactions to the injection site (pain, redness, rash, swelling, itching, or bruising). Each medication has its own list of possible side effects, and patients should talk with their doctor about what to expect. Any new or worsening side effects should be reported to a doctor or healthcare professional.

Written by: Emily Downward | Last reviewed: February 2019
  1. Ward MM, Deodhar A, Akl EA, et al. American College of Rheumatology/Spondylitis Association of America/Spondyloarthritis Research and Treatment Network 2015 Recommendations for the Treatment of Ankylosing Spondylitis and Nonradiographic Axial Spondyloarthritis. Arthritis Rheumatol. 2015;68(2):282-98.
  2. A guide to biologic therapy. National Ankylosing Spondylitis Society. Available at https://nass.co.uk/wp-content/uploads/resources/Guide-to-Biologic-Therapy.pdf. Published 6/17. Accessed 1/18/19.