Inside the Risankizumab and PsA Risk Study: Claims Data on Targeted Immunomodulator Therapies

This episode, "Inside the Risankizumab and PsA Risk Study: Claims Data on Targeted Immunomodulator Therapies," examines the study design and the numbers behind it.

Dr. Strober details the real-world study at the center of the presentation. It examined psoriatic arthritis developing in patients with psoriasis without prior joint disease who started a targeted immunomodulatory drug, or TIM. The analysis compared patients started on risankizumab against those on other TIMs. It drew on the Merative MarketScan claims database, spanning roughly 300 million commercially, Medicare, and Medicaid-insured lives. Psoriatic arthritis was captured by diagnostic codes, which he flags as a known limitation of claims data.

He explains the eligibility rules: psoriasis defined by two visits at least 31 days apart, adult patients naive to modern therapeutics, and continuous enrollment before and after an index treatment. To isolate true first-onset disease, the study excluded anyone with prior inflammatory arthritis, a rheumatology visit, or a suggestive treatment such as methotrexate. Dr. Strober acknowledges this cannot perfectly remove existing psoriatic arthritis, but calls it a rigorous attempt.

Patients were followed after starting an index biologic, risankizumab, ustekinumab ixekizumab, guselkumab, secukinumab, or bimekizumab, or oral apremilast, with sensitivity analyses at 3, 6, and 12 months. Across roughly 20,000 patients, baseline demographics were balanced: average age about 44, half women, with comparable comorbidities across groups.

The crude incidence of psoriatic arthritis, in events per 100 patient-years, was lowest with risankizumab, including versus the other IL-23 inhibitor guselkumab, and clearly below the IL-17 inhibitors, apremilast, and ustekinumab. Adjusted hazard ratios used risankizumab as the reference, and every other TIM showed a statistically significant higher risk. Dr. Strober explains that the 3-, 6-, and 12-month sensitivity analyses test whether effects hold as patients drop out. The results stayed consistent across all intervals.

The next episode in this series, "Reading the Risankizumab Claims Data: Protopathic Bias and Study Limitations," turns a critical eye on how far these claims-based results can be trusted.