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Psoriatic Arthritis: Latest Research

Medically Reviewed by Stephanie S. Gardner, MD on March 31, 2022

Psoriatic arthritis (PsA) has been around for thousands of years. Archaeologists unearthed Egyptian mummies with signs of the disease. Back then, the treatments for swollen and painful joints and red, itchy skin plaques included tar and arsenic. But today, we have other options.

We still don't have a cure for psoriatic arthritis. But biologic drugs and other new treatments like JAK inhibitors target the root causes of joint and skin symptoms.

New research is helping doctors better understand and manage psoriatic arthritis.

Advances in Diagnosis

About 30% of people with psoriasis eventually get psoriatic arthritis. But in more than half of those people, the diagnosis is delayed for 2 years or more after symptoms start. That's a problem, because the longer psoriatic arthritis is left untreated, the more joint damage it causes.

Swelling and joint pain -- especially in areas like the back, knees, fingers, and hands -- could signal that psoriatic arthritis is in your future.

A psoriatic arthritis diagnosis can’t be confirmed with one test. Doctors use a combination of imaging tests like X-rays and MRI scans, plus blood tests. But mainly, your doctor can diagnose PsA based on the presence of the rash and characteristic symptoms like inflammatory arthritis, dactylitis (swelling of fingers and toes), and enthesitis (inflammation where tendons or ligaments attach to bones).

New Treatments

Biologics

Psoriatic arthritis treatments like creams and ointments manage symptoms. But as researchers have learned more about the processes in the body that cause PsA, it’s helped pave the way for new treatments.

One important discovery is that immune system proteins like TNF-alpha, IL-17-A, and IL-12 and 23 trigger inflammation and joint damage. Biologic drugs such as adalimumab (Humira), etanercept (Enbrel), infliximab (Remicade), secukinumab (Cosentyx), ixekizumab (Taltz), and ustekinumab (Stelara) target these proteins to slow the disease. These drugs are also called conventional disease-modifying antirheumatic drugs (DMARDs) or biologic DMARDs.

Guselkumab (Tremfya) is the newest biologic drug approved to treat PsA. It's the first biologic to target the immune system protein IL-23. Another IL-23 drug called risankizumab (Skyrizi) is already approved to treat psoriasis and PsA.

About a dozen biologics are FDA-approved for psoriatic arthritis.

Biologics can lose their effectiveness after a while, so a drug that was helping you could stop helping. In that case, your doctor will likely try another medication either in the same class or a different one, like a JAK inhibitor.

Drugs that act and look similar to the biologics are called biosimilars. Adalimumab has several biosimilars: Abrilada, Amgevita, Cyltezo, Hadlima, Hulio, and Imraldi. Etanercept has two: Erelzi and Eticovo. And Infliximab has four: Avsola, Inflectra, Ixifi, and Renflexis.

Apremilast (Otezla) is another drug that has been approved to treat psoriasis and PsA. It blocks production of the enzyme PDE4, and that reduces inflammation.

Biologic drugs have improved the outcomes for people with psoriatic arthritis, but they're not cheap. These drugs can cost thousands of dollars each month. They can also take a few months before you start to feel their effect.

Possible side effects of biologics include:

  • Upper respiratory infections
  • Flu-like symptoms
  • Headache
  • Urinary tract infections
  • Skin reactions at infection site

Other, more serious side effects can happen. For example, adalimumab and etanercept can cause numbness and tingling; swelling on the face, feet, ankles, and lower legs; hives; and unusual bleeding and bruising, among others. It is important to discuss potential side effects with your doctor before you start taking the drug. You need to know which ones are serious enough that you need to get immediate emergency care versus those that can be dealt with over the phone or during a follow-up appointment.

Be sure to mention to your doctor if you are pregnant or planning on becoming pregnant. A few biologics are safe for use during the first half of pregnancy, while others should not be used at all. You also should not get a live vaccine while taking biologics. Speak to your doctor about which vaccines you should have before you start treatment and which ones are safe during treatment.

JAK inhibitors

Janus kinase (JAK) inhibitors are targeted disease-modifying antirheumatic drugs (DMARDs). The FDA originally approved them for treating rheumatoid arthritis and other diseases. In 2017, the FDA added psoriatic arthritis for one JAK inhibitor, tofacitinib (Xeljanz), if traditional DMARDs were not effective. Another JAK inhibitor, upadacitinib (Rinvoq), is also FDA-approved for PsA.

JAK inhibitors zero in on specific cells and block the action of JAK enzymes. JAK enzymes transmit signals to the cells that increase inflammation. Tofacitinib targets two enzymes in particular, JAK1 and JAK3. Upadacitinib blocks JAK1.

Targeted DMARDs can start working within weeks instead of months, but they are not generally the first treatment used for psoriatic arthritis. They are used if biologics or conventional DMARDs aren’t effective.

As with biologics, you should be up to date with your vaccines before you start taking tofacitinib or upadacitinib. Ask your doctor about which vaccines you can have while taking JAK inhibitors.

Doctors don’t recommend JAK inhibitors if you are pregnant, planning on becoming pregnant, or are nursing, so speak with your doctor about any plans you have to become pregnant in the future. 

Some drugs can also cause serious side effects if you take them along with your JAK inhibitor. Your doctor may choose to switch your medication, change the dosages, or monitor you closely for any potential problems.

Tell your doctor or pharmacist if you take over-the-counter medications, supplements, or vitamins to be sure you aren't taking something that interacts with your treatment.

Some of the drugs that can cause side effects if taken with tofacitinib include:

  • Fluconazole (Diflucan), an antifungal
  • Carbamazepine (Carbatrol, Equetro, Tegretol, others), phenytoin (Dilantin, Phenytek), and phenobarbital, which are anticonvulsants
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, naproxen
  • Nefazodone, an antidepressant

You shouldn’t take upadacitinib with:

  • Other JAK inhibitors
  • DMARDs
  • Immunosuppressants

The standard dose for oral tofacitinib to manage psoriatic arthritis is 5 milligrams twice a day. There is also an extended-release version that’s 11 milligrams once a day. Your dose may vary if you have other medical problems, like kidney or liver disease. The typical dose for upadacitinib is one 15 milligrams tablet a day.

You can take your medication with or without food at any time, but it’s important to take it at the same time each day. If you are taking the liquid form of tofacitinib, be sure to use a dosing syringe you get from the pharmacist. Don’t use standard kitchen measuring spoons; they’re not accurate enough for medications. If you’re taking the extended-release tablets, don’t crush, break, or chew them.

Before you fill your prescription, check with your insurance company to see how much of the cost they’ll cover. Prices can vary, but the average cost of tofacitinib is between $100 per tablet for regular tofacitinib tablets and $200 for extended release. Many pharmaceutical companies have programs to help you afford your medications if they’re too expensive.

JAK inhibitor side effects

As with all drugs, tofacitinib can cause side effects. The most common ones are:

  • Diarrhea
  • Headache
  • Runny or stuffy nose

There are other side effects that could be more serious. If you have any of these, contact your doctor immediately or go to the closest emergency room:

  • Clay-colored stool
  • Dark urine
  • Jaundice (yellow eyes and skin)
  • Pale skin. For people with dark skin, this can be more of an ash color.
  • Shortness of breath
  • Signs of an allergic reaction, such as hives, swelling in your throat, difficulty breathing or swallowing
  • Skin rash
  • Stomach pain
  • Vomiting

Upadacitinib may cause:

  • Bronchitis
  • Herpes simplex
  • Acne
  • Herpes zoster

Before prescribing a JAK inhibitor, your doctor needs to know your complete medical history. Some conditions could get worse if you take the drug.

The most common issues that could result in severe side effects or your psoriatic arthritis getting worse include:

  • Anemia
  • Diverticulitis, ulcers, bowel perforations
  • Diabetes
  • Heart disease
  • Kidney disease
  • Liver disease
  • Tuberculosis

If you smoke or used to smoke, you could have a higher risk of serious side effects from the drug too.

FDA alerts for JAK inhibitors

Since the FDA approved JAK inhibitors to treat psoriatic arthritis, there have been reports of serious side effects among some people. For this reason, the FDA has issued new and updated warnings about these drugs.

The update warns people about the increased risk of blood clots, heart attacks, strokes, cancer, or death. The risk increases for patients who smoke or are former smokers.

If you have a weakened immune system, biologics and JAK inhibitors could increase your risk of getting infections.

Lifestyle Changes

Because the cost of medical treatments is so high, researchers are looking into more cost-effective ways to control PsA. Lifestyle changes like exercise and weight loss could be key.

We already know that people who are overweight or obese are more likely to get psoriatic arthritis. And people who do have the disease often have more joint pain and other symptoms if they weigh more than is recommended for their height.

Losing 5% to 15% of your body weight (about 20 pounds if you weigh 200 pounds) might be enough to improve psoriatic arthritis symptoms.

Weight loss and exercise could also help people with psoriatic arthritis avoid heart disease and metabolic syndrome, which are more of a risk for people with this condition.

Show Sources

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