FDA Clears Psoriasis Biologic ILUMYA for Psoriatic Arthritis

By Grace Kim

The FDA has approved ILUMYA (tildrakizumab-asmn) for adults with active psoriatic arthritis, expanding a biologic already cleared for moderate-to-severe plaque psoriasis since 2018. Dermatology Times first reported the decision. About 2.4 million people in the U.S. live with psoriatic arthritis, according to the drug's manufacturer, Sun Pharma.

The indication matters for dermatology patients specifically. Sun Pharma estimates one in three people with psoriasis will develop PsA. More than 15 percent of people with psoriasis may already have undiagnosed disease.

PsA is a chronic inflammatory condition. It can strike joints across the body, including the spine, fingers and toes, the sites where tendons and ligaments attach to bone, and the skin. Without proper treatment, ongoing inflammation can cause permanent joint damage and disability.

How did the drug perform in trials?

The approval rests on two late-stage trials, INSPIRE-1 and INSPIRE-2, both conducted in adults with active PsA. Each measured the share of patients achieving at least a 20-percent improvement in joint symptoms by week 24.

• In INSPIRE-1, 61 percent of patients on ILUMYA hit that mark, versus 35 percent on placebo.
• In INSPIRE-2, the figures were 64 percent and 33 percent.

Improvements appeared as early as week 8 and continued through week 24, according to the trial data. The drug also improved other disease measures. These included enthesitis, inflammation where tendons attach to bone, and dactylitis, swelling of entire fingers and toes.

A caveat: a 20-percent improvement is a modest bar, and the trials tracked symptoms only to week 24. Longer-term joint-damage data are not part of the announcement.

What does the dosing look like?

ILUMYA is delivered as a 100-mg injection by a health care provider. Patients receive two starter doses four weeks apart, then one dose every 12 weeks. The drug blocks IL-23, a protein that drives inflammation in both psoriasis and PsA. Sun Pharma says it is the only IL-23 inhibitor for PsA administered exclusively by a provider.

Safety in the PsA trials matched the established profile in plaque psoriasis, with no new safety signals. ILUMYA may raise infection risk, and patients require tuberculosis screening before starting. The most common side effects, seen in at least 3 percent of PsA patients, were upper respiratory infections and COVID-19.

What are doctors saying?

"Psoriatic arthritis is a complex and chronic disease. As clinicians, we need a range of therapeutic options that allow us to individualize care based on each patient's symptoms and treatment goals," Seattle rheumatologist Philip Mease, MD, said in a statement. Mease directs rheumatology research at Swedish Medical Center and Providence St Joseph Health and serves as clinical professor at the University of Washington School of Medicine. He added that a provider-administered IL-23 inhibitor gives appropriate patients another option while increasing engagement with their care team.

Christopher Bunick, MD, PhD, editor in chief of Dermatology Times, called evaluating and managing PsA an integral part of dermatology care for psoriasis patients. "The goal should always be to protect and/or treat joints in our psoriasis patients," he said.

What comes next for the label?

The PsA approval is ILUMYA's fourth indication in seven years. The FDA first cleared the drug in 2018 for moderate-to-severe plaque psoriasis in candidates for systemic therapy or phototherapy, then added scalp psoriasis in 2024 and nail psoriasis in 2025. For psoriasis patients, the practical takeaway is concrete: early joint stiffness is easy to dismiss as a hard workout or poor sleep, but the approval gives dermatologists one more way to treat skin and joints within a single regimen.