Sun Pharma's IL-23 inhibitor tildrakizumab gains a psoriatic arthritis indication; the announcement cited no phase 3 efficacy figures.
FDA has approved Sun Pharma’s Ilumya (tildrakizumab-asmn) for adults with active psoriatic arthritis, the company announced Oct. 30.1 The decision adds a second disease to the label of the interleukin-23 (IL-23) inhibitor, which FDA first approved in 2018 for moderate-to-severe plaque psoriasis.
The expansion extends the product from dermatology into rheumatology, where Sun Pharma estimates that as many as 2.4 million Americans live with the disease.1
“FDA approval of Ilumya for adults with active psoriatic arthritis represents another important innovative medicine milestone for Sun Pharma and builds on the established clinical experience of Ilumya in plaque psoriasis,” said Rick Ascroft, North America CEO, Sun Pharma. “As an IL-23 inhibitor administered exclusively by a healthcare provider, Ilumya is now an option for adults with active psoriatic arthritis who are unable to self-administer treatment or who may benefit from regular in-office care.”1
Sun Pharma is positioning provider administration as the product’s distinguishing feature. The announcement did not address launch timing, pricing or how payers might view an in-office model.
Ilumya is also approved for plaque psoriasis in India, Australia, Canada, China and Japan, and in Europe as Ilumetri, which Almirall markets.1
The approval rests on two phase 3 studies, INSPIRE-1 and INSPIRE-2, which compared Ilumya 100 mg with placebo over 52 weeks in adults with active psoriatic arthritis.1 INSPIRE-1 enrolled patients with prior exposure to a tumor necrosis factor (TNF) inhibitor and INSPIRE-2 enrolled patients without it; together they included more than 800 participants.
The primary endpoint was the proportion of patients achieving at least a 20% improvement in American College of Rheumatology response criteria (ACR20) at week 24, and the company reported in 2025 that both studies met it.2 The announcement did not include ACR20 response rates.
Sun Pharma said the studies identified no new safety signals and that safety was consistent with the drug’s established profile. Upper respiratory tract infections were among the most common adverse reactions in the arthritis studies, and patients should be evaluated for tuberculosis before treatment begins.1
Psoriatic arthritis can cause joint pain, swelling and stiffness that may lead to permanent joint damage, and roughly one in three people with psoriasis also have it, according to the company. Sun Pharma adds that more than 15% of people with psoriasis may have undiagnosed psoriatic arthritis.1
Treatment options already include biologic drugs that target TNF and targeted synthetic agents.3
“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. Adding an IL-23 inhibitor option that is administered by a healthcare provider gives us a new way to offer appropriate patients additional support and engagement with their healthcare team,” said Philip Mease, Director of Rheumatology Research at the Swedish Medical Center and Providence St Joseph Health and Clinical Professor at the University of Washington School of Medicine, Seattle, WA.1
Mease was first author of the earlier phase 2b study of tildrakizumab in the condition.3
Ilumya’s psoriasis record is longer than its arthritis record. In the phase 3 reSURFACE 1 and 2 trials, 61% to 66% of patients receiving 100 mg or 200 mg achieved a 75% improvement in the Psoriasis Area and Severity Index at week 12, compared with 6% on placebo.4
In a phase 2b study of 391 patients with active psoriatic arthritis, 71.4% to 79.5% of those receiving Ilumya reached ACR20 at week 24, versus 50.6% on placebo. A higher-than-expected placebo response made results harder to interpret, and improvement in dactylitis and enthesitis was not observed.3
Sun Pharma said in 2025 that full phase 3 findings would be presented at a future medical meeting and published.2 The Oct. 30 announcement included no effect sizes, secondary endpoints or results by prior TNF exposure.1
Efficacy was assessed after two doses at 24 weeks, but the announcement did not describe how durable responses were beyond that point.1 Whether the high placebo response seen in the phase 2b study recurred in the phase 3 studies cannot be assessed without the data.
