Ankylosing spondylitis (AS) is a chronic autoimmune disease that affects the spinal joints and hips. Inflammation, resulting from the immune system attacking the body, causes fusing of joints in sections of the spine, which often leads to pain, swelling, and stiffness. This can limit mobility, making it difficult to complete everyday tasks.

There’s no cure for this disease, but different treatments can slow the progression and help you live an active life. Your doctor will come up with a treatment plan for you after your diagnosis.

Because symptoms of AS can range from mild to severe, some people can control their symptoms with nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Motrin, Advil) and naproxen sodium (Aleve).

If symptoms don’t respond to those, prescription medications are the next line of defense. Such prescription drugs used for AS include disease-modifying antirheumatic drugs (DMARDs) to reduce the strength of your immune system and decrease inflammation.

NSAIDs and DMARDs are both designed to stop inflammation, although they’re unable to target the exact cause of it.

Sometimes pain and stiffness brought about by AS doesn’t respond to these prescription medications. To help you manage symptoms, your doctor may recommend a different type of therapy called biologics.

What are biologics for AS?

Biologics are genetically engineered proteins, created from living organisms, that mimic normal biological functions. They are targeted therapies aimed at specific proteins in the immune system that produce inflammation, namely tumor necrosis factor (TNF) and interleukin 17 (IL-17).

The first biologic was approved by the U.S. Food and Drug Administration (FDA) in 1988 to treat rheumatoid arthritis. Since then, several other biologics have been developed. Currently, six types of biologics are approved for the treatment of AS. These include:

1. Tumor necrosis factor (TNF) blockers

  • adalimumab (Humira)
  • certolizumab pegol (Cimzia)
  • etanercept (Enbrel)
  • golimumab (Simponi, Simponi Aria)
  • infliximab (Remicade)

2. Interleukin 17 (IL–17) inhibitors

  • secukinumab (Cosentyx)

How are biologics for AS given?

Biologics must be delivered into tissue just under the skin or deep into muscle. They’re not available in pill or oral form. You receive them through injections or infusions.

The frequency of injections or infusions needed will vary depending on the particular biologic therapy. You may receive an infusion every few months. Or you may require multiple starter injections, and then follow-up injections throughout the year.

For example, the biologic Simponi requires three starter injections — two injections on the first day of treatment and one injection two weeks later. Afterward, you’ll give yourself one injection every four weeks. If you take Humira, on the other hand, you’ll give yourself one injection every other week after four starter doses.

Your doctor will let you know how often you’ll need biologic therapy, and you’ll receive instructions on how to administer your injections.

Biologics don’t improve symptoms of AS overnight, but you should begin to feel better in about 4 to 12 weeks, sometimes sooner. The goal of treatment is to suppress your symptoms so that the condition doesn’t interfere with your life. Biologics won’t cure AS.

How to find the right biologic therapy for AS

Although all biologics for AS are intended to slow the progression of the disease and stop inflammation, biologics don’t work the same for everyone.

If you begin biologic treatment, your doctor may start you off with one type and monitor your condition over the next three months to see if there’s any improvement. Don’t feel discouraged if your symptoms don’t lessen after your initial infusions or injections. If your AS doesn’t improve, your doctor may suggest switching to a different biologic approved for AS.

Biologic therapy alone isn’t the only option. Finding relief from AS is sometimes a matter of trial and error. You shouldn’t take more than one biologic at a time due to the risk of infection, but you can take biologics with other medications for AS. Be patient — it may take time to find the right combination of drugs. For instance, though your symptoms didn’t improve while taking NSAIDs or DMARDs, combining a biologic with these medications may be effective.

Side effects of biologics for AS

There’s the risk of side effects or allergic reactions with many types of medications, and biologics are no exception.

Side effects of biologic therapy can include pain, redness, rash, or bruising at the injection site. These side effects are usually mild and go away. However, you should notify your doctor if you have symptoms like hives, swelling, or difficulty breathing, as these could be signs of an allergic reaction.

Because biologics suppress your immune system, they can increase your risk of infections and cancer. Your doctor may complete blood work prior to your first injection or infusion to check for tuberculosis, hepatitis B and C, and other infections.

See your doctor if you develop signs of an infection after beginning treatment, such as a fever, chills, shortness of breath, and coughing. Also, notify your doctor if you have unexplained bruising, weight loss, or unusual tiredness. Biologics may increase the risk of blood cancers such as lymphoma.

The takeaway

Without proper treatment, AS can gradually progress and cause increased pain and stiffness. Talk to your doctor if you feel that your current therapy isn’t working. You might be a candidate for biologics. But before starting biologic treatment (as with any treatment), make sure you know your options and ask questions.