POS0249 ASSOCIATIONS BETWEEN CLINICAL CHARACTERISTICS AND SCREENING MRI FINDINGS: EXPLORATORY ANALYSIS OF THE ONGOING PHASE 4, MULTICENTER, RANDOMIZED, CONTROLLED STAR STUDY OF BIOLOGIC-NAÏVE PATIENTS WITH PsA WITH MRI-CONFIRMED AXIAL INVOLVEMENT

Background: Patients (pts) with psoriatic arthritis (PsA) can potentially develop axial inflammation in the sacroiliac joints (SIJs) and/or spine. Although validated classification criteria exist for axial spondyloarthritis, established criteria for classifying axial PsA are lacking. STAR (NCT04929210), a Phase 4, multicenter, randomized, controlled trial of biologic-naïve PsA pts with current neck/back/hip (spinal) pain and magnetic resonance imaging (MRI)-confirmed axial inflammation, is prospectively evaluating the efficacy of guselkumab (GUS), a human IL-23p19-subunit inhibitor, on axial symptoms and objective measures (MRI) of axial inflammation.1 Objectives: This exploratory analysis of available screening MRI data from STAR compared clinical characteristics between pts meeting vs not meeting STAR MRI eligibility criteria. Methods: STAR is designed to randomize (1:1:1) 405 pts to GUS every 4 weeks (Q4W); GUS at W0, W4, then Q8W; or placebo→GUS Q8W at W24. Eligibility criteria include active PsA (≥3 swollen and ≥3 tender joints, C-reactive protein CRP ≥0.3 mg/dL) despite non-biologic disease-modifying antirheumatic drugs (DMARDs), apremilast, and/or non-steroidal anti-inflammatory drugs (NSAIDs). Eligible pts are naïve to biologics/Janus kinase inhibitors and have Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) ≥4, BASDAI spinal pain score ≥4, and screening MRI-confirmed axial involvement (positive spine and/or SIJ MRI defined by blinded, centrally-read Spondyloarthritis Research Consortium of Canada SPARCC score ≥3). SIJ/Spine MRI reading involves 2 central readers and an adjudicator, requiring agreement by 2 readers to confirm a positive (+) or negative (─) MRI result. Pt clinical characteristics and medical history documented at screening were compared between MRI+ and MRI─ cohorts to determine those associated with MRI-detected inflammation of the SIJ and/or Spine (Figure 1). Results: Among 487 pts screened to date in STAR, those with non-missing MRI results included 459 for the SIJ (34% of whom were MRI+), 461 for the Spine (30% MRI+), and 433 for both the SIJ and Spine (15% with SIJ+/Spine+, 26% with SIJ+/Spine─ or SIJ─/Spine+, 59% with SIJ─/Spine─). Percentage of males and serum CRP levels were significantly higher in both SIJ+ vs SIJ─ and Spine+ vs Spine─ cohorts. The SIJ+ cohort was characterized by younger age (mean: 44.7 vs 47.4 yrs), a higher spinal pain score (mean: 7.7 vs 7.3), and fewer tender joints (mean: 12.6 vs 15.5) vs the SIJ─ cohort (all nominal pTable 1). The SIJ+ cohort comprised numerically higher proportions of pts with a history of inflammatory back pain, nail psoriasis, and scalp psoriasis than the SIJ─ cohort. Pts with a history of palmoplantar psoriasis appeared less likely to exhibit MRI-detected inflammation in the SIJ or Spine (Figure 1). Differences between the SIJ+/Spine+ (N=65) and SIJ─/Spine─ (N=257) cohorts were generally aligned with those of the site-specific cohorts (data not shown). Conclusion: Preliminary findings from an established PsA cohort in STAR are: 1) consistent with the recognized positive association between serum CRP levels and axial involvement in PsA and 2) provide initial evidence that several clinical characteristics may also associate with the presence or absence of MRI-detected axial inflammation. The STAR study is actively enrolling. REFERENCES: 1 Gladman. Trials. doi.org/10.1186/s13063-022-06589-y. Acknowledgements: NIL. Disclosure of Interests: Xenofon Baraliakos - Speaker's bureau: AbbVie, Chugai, Eli Lilly, Janssen, MSD, Novartis, Pfizer, Roche, and UCB, Consultant: AbbVie, Chugai, Eli Lilly, Janssen, MSD, Novartis, Pfizer, Roche, and UCB, Grant/research support: AbbVie, Eli Lilly, Janssen, MSD, and Novartis, Paul Bird - Speaker's bureau: AbbVie, Eli Lilly, Gilead, Janssen, MSD, Pfizer, and UCB, Consultant: Eli Lilly, Gilead, Janssen, Novartis, and Pfizer, Atul Deodhar - Speaker's bureau: Eli Lilly, Janssen, Novartis, Pfizer, and UCB, Consultant: AbbVie, BMS, Celgene, Eli Lilly, Janssen, Novartis, Pfizer, and UCB, Grant/research support: AbbVie, Eli Lilly, Novartis, Pfizer, and UCB, Dafna D. Gladman - Consultant: AbbVie, Amgen, BMS, Celgene, Eli Lilly, Galapagos, Gilead, Janssen, Novartis, Pfizer, and UCB, Grant/research support: AbbVie, Amgen, BMS, Celgene, Eli Lilly, Janssen, Novartis, Pfizer, and UCB, Philip S Helliwell - Paid instructor: AbbVie, Amgen, Novartis, and Janssen, Consultant: Eli Lilly, Denis Poddubnyy - Consultant: AbbVie, Biocad, BMS, Eli Lilly, Gilead, GSK, MSD, Novartis, Pfizer, Roche, and UCB, Grant/research support: AbbVie, Eli Lilly, MSD, Novartis, and Pfizer, Arthur Kavanaugh - Consultant: AbbVie, Amgen, BMS, Eli Lilly, Gilead, Janssen, Novartis, Pfizer, and UCB, Mikkel Østergaard - Speaker's bureau: AbbVie, Boehringer-Ingelheim, BMS, Celgene, Eli Lilly, Hospira, Janssen, MSD, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi, and UCB, Consultant: AbbVie, Boehringer-Ingelheim, BMS, Celgene, Eli Lilly, Hospira, Janssen, MSD, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi, and UCB, Grant/research support: AbbVie, BMS, Celgene, and Novartis, Enrique R. Soriano - Speaker's bureau: AbbVie, Amgen, BMS, Eli Lilly, Janssen, Novartis, Pfizer, Roche, and UCB, Consultant: AbbVie, Janssen, Novartis, and Roche, Grant/research support: AbbVie, Janssen, Novartis, Pfizer, Roche, and UCB, Lai-Shan Tam - Consultant: Janssen, Pfizer, Sanofi, AbbVie, Boehringer Ingelheim, and Eli Lilly, Grant/research support: Amgen, Boehringer Ingelheim, Janssen, GSK, Novartis, and Pfizer, Soumya D. Chakravarty - Shareholder: Johnson & Johnson, Employee: Janssen Scientific Affairs, LLC, Evan Leibowitz - Shareholder: Johnson & Johnson, Employee: Janssen Scientific Affairs, LLC, Cinty Gong - Shareholder: Johnson & Johnson, Employee: Janssen Scientific Affairs, LLC, Stephen Xu - Shareholder: Johnson & Johnson, Employee: Janssen Research & Development, LLC, Thomas Fuerst - Shareholder: Clario, Employee: Clario, Nadeem Saeed - Employee: Clario, Robert Landewé - Consultant: AbbVie, Galapagos, Eli Lilly, Janssen, Novartis, Pfizer, and UCB, Philip J. Mease - Speaker's bureau: AbbVie, Amgen, Eli Lilly, Janssen, Novartis, Pfizer, and UCB, Consultant: AbbVie, Acelyrin, Aclaris, Amgen, Boehringer Ingelheim, BMS, Eli Lilly, Galapagos, Gilead, GSK, Immagene, Janssen, Novartis, Pfizer, SUN, UCB, and Ventyx, Grant/research support: AbbVie, Acelyrin, Amgen, BMS, Eli Lilly, Janssen, Novartis, Pfizer, SUN, and UCB.