Biologics are drugs that work by limiting the immune system’s inflammatory response. Although biologics may be an effective treatment option for ankylosing spondylitis (AS), they may not be right for everyone.

Biologics are a type of medication made from living organisms. Doctors use them to target specific parts of the immune system to reduce or prevent an inflammatory response.

AS is a type of inflammatory arthritis that often affects the spine and large joints. As the disease progresses, it can affect other joints in the body, as well as certain organs, such as the eyes. It can also cause the spine to fuse, further limiting mobility and flexibility.

Biologics have many benefits, including limited side effects and the ability to target specific immune pathways. However, they are not a first-line treatment, come at a considerable cost, and require an injection or IV for administration. A person can get advice from a doctor regarding whether biologics are right for them.

Biologics are disease-modifying antirheumatic drugs (DMARDs) made from living tissue. A doctor may prescribe them when traditional DMARDs have not worked.

Due to manufacturing challenges, biologics cost more than other medications. They are also only available as an injection or IV infusion.

Although they are often effective, they can result in decreased immune responses. This can make a person more susceptible to infections.

There are four classifications of biologics, each of which targets a different part of the immune system:

  • tumor necrosis factor (TNF) inhibitors
  • interleukin (IL) inhibitors
  • B-cell inhibitors
  • T-cell inhibitors

Of the various types of biologics, only two of the classifications — IL inhibitors and TNF inhibitors — have FDA approval for the treatment of AS.

The first biologic that the FDA approved for use as an AS treatment was a TNF inhibitor called etanercept (Enbrel). The FDA approved it in 2003. Since then, an additional four TNF inhibitors have gained FDA approval:

  • Humira (adalimumab)
  • Remicade (infliximab)
  • Simponi (golimumab)
  • Cimzia (certolizumab pegol)

Each drug works slightly differently, which means that a doctor can often change a person’s medication if their current one does not work or stops working.

The FDA has also approved two IL inhibitors called Cosentyx (secukinumab) and Taltz (ixekizumab), both of which are IL-17 inhibitors.

How they work

A variety of cells, proteins, and organs work together to help keep the body healthy and make up what is known as the immune system.

Certain conditions, such as AS, occur when the immune system attacks healthy cells with an inflammatory response. In recent years, scientists have found that two types of proteins, known as IL and TNF, play a significant part in causing inflammation throughout the body.

Biologics work by replicating these proteins, thereby blocking their receptors. This stops the immune system from producing inflammation. Stopping or slowing inflammation helps reduce AS symptoms.

These medications may also help prevent damage to the joints and reduce the risk of complications associated with AS.

In other words, biologics provide a targeted treatment for inflammation by going after specific inflammation signaling pathways in the immune system.

Biologics can provide effective therapy for AS symptoms and help a person achieve remission. Doctors often prescribe them when a person’s symptoms do not respond to other treatment options.

TNF inhibitors can provide two forms of inflammation relief. They can stop the inflammation in the joints and also reduce or stop inflammation in other areas of the body, such as the eyes or gut.

Reducing inflammation can help prevent complications and worsening disease severity.

Another advantage of biologics is that a doctor can choose from a few different options. This allows them to change therapeutic approaches if the current biologic does not work or stops working.

They are also generally well-tolerated. This means that people are not likely to develop serious side effects or complications as a result of taking the medications.

In studies, researchers have noted that people generally respond well to biologics, experiencing limited side effects. However, that does not mean they have no risks.

Some potential side effects include:

  • reactions at the injection site, such as swelling, itchiness, or soreness
  • increased risk of infections
  • infusion reaction, such as nausea, headaches, or pain

A person should let their prescribing doctor know about any side effects they develop and whether these change or worsen over time. The doctor can help determine whether another medication might work better for them.

Biologics can provide a targeted, effective, and well-tolerated treatment for AS, particularly for those who have not responded well to other treatment options. They work by blocking specific protein receptors, which prevents the immune system from producing inflammation.

Reduced inflammation allows for AS symptom remission and helps prevent further complications associated with AS. A doctor can help a person determine whether biologics are a good option for their treatment.