If your psoriatic arthritis (PsA) has not responded to first-line treatments, your doctor may suggest you try more potent drugs called monoclonal antibodies, a type of biologic drug, and often more commonly referred to simply as biologics.
Psoriatic Arthritis and Inflammation
When you have an autoimmune disease, the immune system mistakenly attacks your own body. The immune system causes the affected area to become inflamed. This inflammation causes a part of your body to become swollen, hot, red, or sore. It is meant to kill invading germs. Unfortunately, it can also harm your own cells.
In psoriasis, your immune system causes inflammation in your skin. In arthritis, the inflammation affects your joints. In PsA, it affects both.
How Biologics Work to Treat Psoriatic Arthritis
Some PsA medications work by calming down the inflammation. For example, NSAIDs work this way. Corticosteroids do this by calming down the immune system. Biologics work a little differently.
Biologics are a newer type of disease-modifying antirheumatic drug (DMARD). Biologics are usually prescribed for people with moderate to severe PsA. These drugs also calm down the immune system, but only affect certain parts of it. This approach allows most of your immune system to work normally while still preventing inflammation caused by PsA.
How is this possible? The immune system works like a chain email. When confused cells think they are under attack, they send a message to nearby immune cells, who then send messages to other immune cells. But these messages are not emails or phone calls. In fact, they are tiny proteins called cytokines. Cytokines tell immune cells whether or not to launch an attack. Some cytokines encourage inflammation, and others calm it down. When you have PsA, you have too much of the cytokines that cause inflammation.
Biologics are like the spam blocker on your email account. When they see a certain type of cytokine, they block the message.
By blocking the alarm message sent by confused cells, biologics interrupt the chain email before it can spread. This way, they prevent the immune response from spiraling out of control.
Monoclonal antibodies are human-made antibodies created in the lab to mimic antibodies in the body. These biologics focus on certain kinds of cytokines, including tumor necrosis factors (TNFs) and interleukins. There are two main types of biologics approved to treat psoriatic arthritis: TNF inhibitors and interleukin inhibitors.
TNF inhibitors approved to treat PsA include:
- Adalimumab (Humira)
- Certolizumab (Cimzia)
- Etanercept (Enbrel)
- Golimumab (Simponi)
- Infliximab (Remicade)
Interleukin inhibitors approved to treat PsA include:
- Brodalumab (Siliq)
- Guselkumab (Tremfya)
- Ixekizumab (Taltz)
- Risankizumab (Skyrizi)
- Secukinumab (Cosentyx)
- Tildrakizumab (Ilumya)
- Ustekinumab (Stelara)
Biologics work very well for people with PsA. They help lower inflammation in the fingers, toes, entheses (places where a tendon or ligament attaches to a bone), and skin. As a result, these drugs can improve joint function and quality of life. Interleukin inhibitors are especially good at healing skin symptoms.
Symptoms usually improve within 3 to 6 months of starting biologic therapy.
Who Is Most Likely to Benefit?
If you have mild PsA, you might be able to control your symptoms with NSAIDS or corticosteroids.
For moderate to severe PsA, the standard treatment typically is nonbiologic traditional DMARDs like methotrexate and leflunomide (Arava). If they don’t work, doctors may suggest apremilast (Otezla), which does not involve injections. While it’s effective on skin symptoms, it has not yet been proven to prevent joint damage.
There is no evidence that TNF inhibitors or interleukin inhibitors are more effective than the other. Generally, doctors prescribe TNF inhibitors first because they’ve been on the market longer and are often more affordable.
However, TNF inhibitors do not work for some people. If the first TNF inhibitor that you take does not help, your doctor may switch you to another one. If your symptoms do not get better after trying a second TNF inhibitor, they will likely suggest an interleukin inhibitor instead.
How Are Biologics Taken?
Biologics are usually given through a self-injection or an IV infusion given at a clinic or hospital.
If you are taking a biologic, you should visit your doctor every 3 to 6 months to manage side effects and make sure that the treatment is working.
What Are the Side Effects of Biologics?
Because biologics only block certain kinds of cytokines, the rest of the immune system usually can continue to work in a healthy way. However, biologics sometimes slow the immune response against real invading germs. As a result, if you take biologics, you might be more likely to get sick. Because of this risk, you should get tested for infections like hepatitis B and tuberculosis before starting biologic therapy.
Side effects include:
- Allergic reactions (look for shortness of breath, swelling, or itchiness)
- Nonmelanoma skin cancers
- Respiratory infections, like the common cold
- Suicidal thoughts
These side effects are rare but serious:
- Heart failure (look for shortness of breath and swelling of the ankles or hands)
- Lupuslike syndrome (look for rash on the face and new joint pain)
- Numbness or tingling
- Sudden vision problems
Sometimes, the immune system might attack the drug itself. When this happens, the treatment might not work as well. If you’re taking a TNF inhibitor, adding methotrexate or azathioprine to your treatment regimen can help the TNF inhibitor to work better.
How to Lessen the Side Effects
Headaches. Try putting an ice pack on your forehead, resting in a dim room, or taking a hot shower.
Infections. Wash your hands frequently and stay up to date on vaccines. Keep your distance from people you know are contagious. Talk to your doctor about whether you should avoid crowds, live vaccines, certain foods, or activities like gardening. If you give yourself shots (whether biologics or another therapy), ask your doctor about needle safety and cleanliness.
Mild allergic reactions. Try an ice pack, corticosteroid cream, antihistamines, anti-nausea drug, or NSAID. Talk to your doctor about reactions, especially if they get worse or last for more than 5 days. If you have the following symptoms, stop the treatment and get emergency medical help:
- Chest pain
- Difficulty breathing
- Fever or chills
- High or low blood pressure
- Swelling in your face or hands
Nausea. Drink ice water or peppermint tea, take deep breaths, rest in a quiet place, and avoid sugary drinks or foods.
Who Should Not Take Biologics?
If you have heart failure or multiple sclerosis, you should not take interleukin inhibitors. If you have Crohn’s disease, do not take brodalumab. Avoid any medications that contain drugs that have bothered you in the past.