Achieving “State Zero”: New Data on Bimekizumab, Other IL-17is, Transform PsA Treatment Goals, with Philip Mease, MD

Interleukin-17 (IL-17) inhibition continues to evolve as a major frontier in psoriatic arthritis (PsA) treatment, with new data on both approved and investigational therapies recently presented at the American College of Rheumatology (ACR) Convergence 2025, held October 24–29 in Chicago, Illinois, by Philip Mease, MD, Clinical Professor at the University of Washington and Director of Rheumatology Research at the Swedish Medical Center in Seattle.

In a conversation with HCPLive, Mease spoke about key findings on several IL-17 targeting agents, bimekizumab, sonelokimab, and izokibep, that are shaping current and future management strategies for PsA.

New data on bimekizumab, a dual IL-17a/17f inhibitor, reinforce the importance of achieving complete remission across clinical domains, or "state zero." Mease and colleagues found that when patients reach “state zero”—meaning full resolution of manifestations such as swollen joints, enthesitis, or radiographic progression—they experience substantial parallel improvements in pain, function, and overall quality of life.

Meanwhile, new phase 2 data on sonelokimab, a nanobody IL-17A and IL-17F inhibitor, demonstrated that at 24 weeks, more than half of treated patients achieved major composite outcomes such as ACR50 and minimal disease activity, with responses spanning key domains of arthritis, enthesitis, and skin involvement.

Lastly, Mease discussed 1-year outcomes from izokibep, a small molecule IL-17A inhibitor with a compact protein scaffold design, which demonstrated durable efficacy through 52 weeks. Patients maintained high rates of ACR50 responses, functional improvement, and sustained low disease activity, suggesting that next-generation small molecule constructs may rival biologics in depth and durability of response.

Mease's disclosures include AbbVie, ACELYRIN, Amgen, Bristol Myers Squibb, Century Therapeutics, Cullinan Biotech, Eli Lilly, Genascence, GRAPPA, Immagene, Johnson & Johnson, MoonLake Immunotherapeutics, Novartis, OMERACT, Pfizer, SPARTAN, Takeda, and UCB Pharma.

References

1. Mease PJ, Poddubnyy D, Bajracharya R, et al. Long-Term Safety and Tolerability of Bimekizumab Treatment Across Phase 2b and Phase 3 Studies in Patients with Axial Spondyloarthritis or Psoriatic Arthritis: 3-Year Update from the Phase 3 Studies. Presented at: ACR Convergence 2025; October 24-29; Chicago, Illinois. Poster #1454

2. Mease PJ, Gossec L, Deodhar A, et al. Sonelokimab in Patients With Active Psoriatic Arthritis Who Are Naive to Biologic DMARDs: Phase 2 ARGO Analysis and Phase 3 IZAR-1 Study Design. Presented at: ACR Convergence 2025; October 24-29; Chicago, Illinois. Poster #1455

3. Mease PJ, Behrens F, Kivitz AJ, et al. Efficacy and Safety of Izokibep, a Novel IL-17A Inhibitor, in Patients with Active Psoriatic Arthritis: Week 52 Results from a Randomized, Double-Blind, Placebo-Controlled, Multicenter, Phase 2b/3 Study. Presented at: ACR Convergence 2025; October 24-29; Chicago, Illinois. Poster #LB08