10 JAK Inhibitors in Development: What to Know About Povorcitinib, Delgocitinib, and More

On the surface, health conditions such as rheumatoid arthritis (RA), eczema, and ulcerative colitis (UC) may seem like they have nothing in common. But if you dig a little deeper, a common root issue comes to light — excess inflammation.

Thankfully, many treatments can lessen inflammation. Among them is a group of medications called Janus kinase (JAK) inhibitors. Drugs such as Rinvoq (upadacitinib), Xeljanz (tofacitinib), and Olumiant (baricitinib) highlight the list of JAK inhibitors that are available at pharmacies for you to receive.

At the same time, JAK inhibitors are experiencing a growth spurt. Drug companies and health experts are learning more about their potential benefits, and they’re looking to increase access to this expanding group of medications. This focus has led to more and more JAK inhibitors being prioritized for development.

What JAK inhibitors are currently being developed?

JAKs themselves are a group of enzymes (proteins) that help your immune system communicate and coordinate what it needs to do. JAK inhibitors block the effects of one or more JAK enzymes to help calm an overactive immune response.

Different JAK inhibitors affect the immune system in their own way. Because of this, they each treat their own set of autoimmune disorders or forms of cancer. This is also true for new, upcoming JAK inhibitors in more advanced stages of development.

While not an exhaustive list, we’ll highlight 10 notable JAK inhibitors in development below.

Good to know: Phase 3 clinical trials are typically the last required step before a pharmaceutical company can apply for FDA approval. They came on the heels of preclinical studies, phase 1 trials, and phase 2 trials, among other efforts. 

1. Povorcitinib

Povorcitinib is an oral tablet in development for a handful of health conditions. It’s being evaluated in phase 3 trials for:

• Hidradenitis suppurativa (STOP-HS1, STOP-HS2, STOP-HS LTE), a skin condition caused by sweat gland inflammation

• Prurigo nodularis (STOP-PN1, STOP-PN2), a skin condition that causes itchy bumps

• Nonsegmental vitiligo (STOP-V1, STOP-V2), a skin condition that causes patches of skin to lose their natural color

EXPERT PICKS: WHAT TO READ NEXT

• A full overview: Here’s a deep dive into the list of FDA-approved JAK inhibitors, courtesy of GoodRx pharmacists.

• Are JAK inhibitors biologic medications? Experts explain why JAK inhibitors are not biologics and the differences between them.

• What to expect: Review notable JAK inhibitor side effects — from acne to infections — and how to manage them.

Povorcitinib’s phase 2 studies include:

• Chronic spontaneous urticaria, or chronic hives

• Asthma

According to reporting from the J.P. Morgan Healthcare Conference 2025, povorcitinib’s manufacturer is feeling optimistic about the medication’s potential going forward — especially for hidradenitis suppurativa. Povorcitinib’s clinical trial data should be released over the coming months to years.

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2. Delgocitinib

Delgocitinib is a topical medication, not an oral one; it’s formulated as a 20 mg/g cream. It’s being studied for moderate-to-severe chronic hand eczema (CHE).

Clinical trial data shows that delgocitinib works well to treat eczema on the hands. Over a 16-week (4-month) period, it significantly improved or cleared eczema symptoms compared to a placebo cream (a cream with no medication in it).

This medication is continuing to march forward. Its manufacturer submitted an FDA approval application in September 2024. The FDA is expected to make a decision on the application by mid-to-late 2025.

If approved, delgocitinib would be the first FDA-approved medication for moderate-to-severe CHE. The medication is already approved in places such as Switzerland, the European Union, and Japan.

3. Brepocitinib

Brepocitinib is a once-daily oral medication under investigation for two autoimmune disorders, dermatomyositis and non-infectious uveitis (NIU). Dermatomyositis leads to skin changes and muscle weakness, while NIU is an eye condition that can cause blindness.

Brepocitinib appears to be a useful treatment for both conditions. But more research is underway. Results from a phase 3 trial for dermatomyositis are expected by mid-to-late 2025, and an FDA approval application may follow suit. Meanwhile, a phase 3 study for NIU began in September 2024.

Good to know: Brepocitinib inhibits a JAK protein called JAK1, but it also blocks a protein called tyrosine kinase 2 (TYK2). TYK2 is a type of JAK.

4. Ritlecitinib

Ritlecitinib is a once-daily oral capsule. It’s also one of the newer JAK inhibitors to obtain FDA approval. Under the brand name Litfulo, it was FDA approved in June 2023 to treat severe alopecia areata in adults and kids age 12 and older.

Although ritlecitinib is now approved for alopecia, its work isn’t finished. Ritlecitinib is in a phase 3 clinical trial for vitiligo.

So far, ritlecitinib for vitiligo has produced positive results. A phase 2 clinical trial found that it’s effective and well tolerated for both light and dark skin types. The ongoing phase 3 study is aiming to confirm these findings, and it’s set to end by April 2026. If the data is positive, ritlecitinib’s manufacturer will likely apply for FDA approval shortly after.

Vitiligo aside, ritlecitinib is also being studied for ulcerative colitis (UC) and Crohn’s disease.

5. Itacitinib

Itacitinib is a once-daily oral pill that’s being studied for graft-versus-host disease (GVHD). This is a potential complication that can develop after receiving a stem cell transplant.

A phase 2 trial evaluated itacitinib for low risk, acute GVHD — a type of GVHD that happens within 100 days of a transplant. The study found that itacitinib is about as effective as corticosteroids for managing the condition. A different study found that it wasn’t effective for chronic GVHD, though.

We’re still learning about itacitinib’s benefits and risks overall. But early signs suggest that itacitinib may have less blood-related side effects than Jakafi (ruxolitinib). Itacitinib inhibits one JAK enzyme, while Jakafi inhibits two.

Many early-stage studies are evaluating itacitinib for other uses too. Phase 1/2 studies of Hodgkin lymphoma, leukemia, and systemic sclerosis are underway.

6. Ivarmacitinib

Ivarmacitinib is a once-daily oral tablet that’s being developed for atopic dermatitis, the most common form of eczema.

Reistone Biopharma, ivarmacitinib’s manufacturer, released positive phase 3 data in November 2022. Compared to placebo, participants who received ivarmacitinib were significantly more likely to achieve clear skin after 16 weeks.

At this time, ivarmacitinib’s potential FDA approval timeline is unclear. If it’s approved, it would rival Opzelura (ruxolitinib) and Cibinqo (abrocitinib). Opzelura is a topical cream, whereas Cibinqo is an oral tablet. Reistone is currently prioritizing ivarmacitinib’s use in China.

Ivarmacitinib is also being evaluated as a potential treatment for:

• UC

• Crohn’s disease

• Alopecia areata

• RA

• Triple-negative breast cancer

7. Rinvoq

Rinvoq is another once-daily oral tablet. It's already approved for these health conditions:

• RA

• Psoriatic arthritis

• Ankylosing spondylitis

• Non-radiographic axial spondyloarthritis

• Polyarticular juvenile idiopathic arthritis

• UC

• Crohn’s disease

• Atopic dermatitis

When a drug maker wants their medication to be approved for a new use, they need to provide new data that shows it’s safe and effective for that intended purpose. This is the current situation with AbbVie’s Rinvoq and systemic lupus erythematosus (“lupus”).

In March 2023, AbbVie announced that they’re advancing Rinvoq to phase 3 clinical trials for lupus. Rinvoq’s study for moderate to severe lupus kicked off in July 2023, and it's set to run through October 2027.

8. Ruxolitinib extended-release

Jakafi was the first JAK inhibitor to obtain FDA approval. It was initially approved in 2011 for myelofibrosis, a type of blood cancer. Its other uses came later on. Polycythemia vera (another type of blood cancer) was its second approved indication. Acute and chronic GVHD followed suit.

Now, an extended-release (ER) version of Jakafi is in the works: ruxolitinib ER. However, the FDA denied ruxolitinib ER’s approval request in March 2023. The FDA requested additional information in the application. The manufacturer is working on addressing those concerns.

9. Filgotinib

Filgotinib is a once-daily oral tablet. In Europe, it’s an approved RA and UC medication known by the brand name Jyseleca.

Filogotinib’s future in the U.S. is relatively uncertain. Its manufacturer released phase 3 study data that suggests it isn’t an effective treatment option for moderate-to-severe Crohn's disease. In the past, the FDA also rejected filogotinib’s approval for RA, citing side effect concerns.

What’s more, Galapagos NV — filgotinib’s former manufacturer — sold the medication to a company called Alfasigma in January 2024. Alfasigma is now actively studying the medication for conditions such as juvenile idiopathic arthritis and UC.

10. Londamocitinib

Londamocitinib, also called AZD4604, is unique because of its dosage form. It’s an inhaled JAK inhibitor.

Londamocitinib is actively being studied for asthma in two phase 2 clinical trials (AJAX, ARTEMISIA). These studies are set to run through 2025 and 2026, respectively. If these trials show positive results, phase 3 studies will likely follow.

What JAK inhibitors are currently on the market?

Around 10 JAK inhibitors are available and FDA approved for use. This includes:

• Rinvoq

• Xeljanz

• Olumiant

• Litfulo

• Jakafi

• Opzelura

• Cibinqo

• Vonjo (pacritinib)

• Inrebic (fedratinib)

• Ojjaara (momelotinib)

Another JAK inhibitor, called Leqselvi (deuruxolitinib), was approved in mid 2024. It treats alopecia in adults, following in the footsteps of Olumiant and Litfulo. But its manufacturer announced that its commercial launch has been delayed due to patent reasons. It may not be available until the end of 2026.

Sotyktu (deucravacitinib) adds another layer of complexity. It’s technically a TYK2 inhibitor, but several people consider it to be another JAK inhibitor. It’s approved to treat psoriasis.

What’s so exciting about the new JAK inhibitors being developed?

Autoimmune disorders and cancer can be hard to treat. It’s common to try different treatments before finding one that works well for you. Side effects can also be an issue. As such, developing new-and-improved medications is an ongoing priority.

JAK inhibitors are a growing class of medication that can help address this need. Depending on the health condition, they can start to work relatively quickly and offer relief when other treatments haven’t done the trick. Convenience is also a selling point; JAK inhibitors are often available as oral pills and liquids — not injections.

Some new JAK inhibitors are looking to replace current JAK inhibitors as go-to treatment options. Others want to be the first one available for certain conditions.

Why trust our experts?

Written by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

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