The Consumer’s Guide to JAK Inhibitors for Psoriatic Arthritis

Traditional disease-modifying treatment options include DMARDs, which suppress the immune system on a broad level, and biologics, which are more targeted in how they block immune system activity. But JAK inhibitors work in an even more targeted way. They block specific pathways in the immune response that are thought to be involved in psoriatic arthritis. By blocking the inflammation at its source, the overactive immune response does not “turn on.” This results in better control of disease activity.

In 2017, the FDA approved tofacitinib (Xeljanz®) to treat psoriatic arthritis. In late 2021, they also approved upadacitinib (Rinvoq).

In 2022, deucravacitinib (Sotyktu) became the first FDA-approved JAK inhibitor for treating psoriasis, the skin condition that often goes hand-in-hand with psoriatic arthritis. Even though this drug is not indicated for treating joint symptoms, it’s thought that if you take it for psoriasis, chances are it’ll help improve psoriatic arthritis, as well.

JAK inhibitors are often compared to biologics, as they are both targeted types of psoriatic arthritis treatment. Biologics are given as self-injections, which need to be refrigerated, or by infusion in a medical setting. Biologics need to be administered in intervals ranging from weekly to monthly. By contrast, JAK inhibitors are available in pill form, which you simply take by mouth. “They're definitely less cumbersome in that way,” Mandelin says. “The flip side of it is that they also wash in and wash out of the body quickly. That’s why they are taken daily.”

How quickly JAK inhibitors take effect can vary from person to person. But if they are going to help you, you’ll notice results within three months, Mandelin says. “There is some data out there that suggests some people can experience a meaningful difference as early as two weeks on a JAK inhibitor,” he notes.

A telltale sign that they’re working? You’ll notice you have fewer symptoms. Your doctor will be able to quantify this through blood testing and by asking you questions during your regular checkups.

A study published in March 2020 in the journal Current Dermatology Reports found that tofacitinib is very effective in treating psoriatic arthritis. But that doesn’t mean it’s guaranteed to work for everyone. “If a JAK inhibitor is not helpful, patients often go back to biologics,” Mandelin says.

You can also try the other approved JAK inhibitor to see if that works for you — unless you experienced a side effect specific to the drug class as a whole — adds Nilanjana Bose, MD, a rheumatologist at Memorial Hermann in Houston.

A study published in April 2020 in the Chinese Medical Journal found that an increased risk of infections, such as upper respiratory, was among the most common side effects of JAK inhibitors in people with psoriatic arthritis. This is because JAK inhibitors target parts of the immune system, which can lower your overall immunity.

The safety of JAK inhibitors has also made headlines. Results from a postmarketing  study of tofacitinib delayed FDA approval of certain JAK inhibitors used for RA as treatment for psoriatic arthritis. Findings showed an increased risk of serious heart-related problems and cancer in people taking tofacitinib for RA. As a result, in 2021, a black box warning was added — to all JAK inhibitors, not just tofacitinib.

This is why your doctor may not prescribe a JAK inhibitor if you have cardiovascular issues or a history of blood clots. “But rather than being scared by a warning, I think people with psoriatic arthritis should view this as a caution, as with any kind of [treatment], and do their due diligence,” Dr. Bose adds.

This includes checking your heart health profile, among other things. “Before starting, we also test people to make sure they don’t have any dormant infections in their system that could be woken back up by starting a JAK inhibitor,” according to Mandelin. You may be tested for things such as tuberculosis, hepatitis B, or hepatitis C before you start treatment. Your doctor will also monitor you during the course of treatment for signs of infection. Other possible side effects may include an allergic reaction to the medication or negative effects to the liver, but these are rare, he says.

Even with insurance coverage, JAK inhibitors can still come with significant out-of-pocket costs. “They are very expensive for most people,” says Mandelin. “It does depend on your insurance, but they do tend to be a little bit cheaper than biologics.”

Although JAK inhibitors are costly, they are still cheaper than spending money on a treatment that doesn’t work. A study published in August 2020 in the Journal of Managed Care & Specialty Pharmacy found that for those who did not find success with a traditional disease-modifying antirheumatic drug (DMARD) or a biologic, tofacitinib was associated with a reduction in psoriatic arthritis symptoms and a lower total cost of treatment.

Your doctor may also be able to point you to patient assistance programs, charitable foundations, or other financial options to help lower the cost of JAK inhibitor treatment.