Abstract Background/Aims Ixekizumab (ixe), a highly selective interleukin (IL)-17A monoclonal antibody, has been approved for treatment of psoriatic arthritis (PsA). However, there is limited real-world evidence (RWE) available for ixe. PRO-SPIRIT is the first large-sample prospective observational study to provide RWE for ixe in patients (pts) with PsA. PRO-SPIRIT’s primary objective is to describe treatment persistence at 24 months (M) among pts with PsA who initiate or switch to a new biologic Disease-Modifying Arthritis Rheumatic Drugs (bDMARDs) or targeted synthetic (tsDMARDs), including ixe. This abstract describes the interim baseline (BL) characteristics. Methods PRO-SPIRIT is a prospective observational study, conducted in FR, ES, IT, DE, UK, and CA, enrolling adults with PsA (≥6M) to be initiated or switched to a new b/tsDMARD, locally approved for PsA. Treatment groups include ixe, secukinumab, IL-12/IL-23 inhibitors (i) (ustekinumab) or IL-23i (guselkumab), tumour necrosis factor (TNFi) (adalimumab, etanercept, infliximab or biosimilar), Janus kinase (JAKi) (tofacitinib or upadacitinib). Pt demographic, disease activity and therapy characteristics are collected at BL; clinical and patient-reported outcomes measures are collected at BL and at a routine post-BL visit. BL descriptive statistics are reported. Results From December 2019 until this interim data cut (June 2021), a total of 477 pts (305 female; mean age 52) were enrolled. Mean age ranged from 48 (IL-12/23i and IL-23i) to 55 (JAKi), with a majority of female pts in each group. Pts in the IL-12/23i and IL-23i and TNFi groups showed the shortest time since PsA diagnosis (5.2±4.5; 6.5±7.9), while pts in the JAKi group showed the longest time (10.6±9.4). The lowest proportion of pts with a prior b/tsDMARDs use was observed in the TNFi group (31%), the highest in the IL-12/23i and IL-23i group (71%). Pts in the ixe and IL-12/23i and IL-23i groups were more likely to be on monotherapy. Tender Joint Count (9.1-11.3) and Swollen Joint Count (3.3-5.8) were comparable across groups, with the highest values in the ixe and JAKi groups, respectively. Pt proportion with enthesitis and dactylitis was higher in the ixe, secukinumab and JAKi groups. Percentage of Body Surface Area affected by psoriasis was higher in the ixe, secukinumab and IL-12/23i and IL-23i groups. Pt proportion with nail psoriasis was higher in the ixe and secukinumab groups. Physician's Global Assessment Visual Analog Scale (VAS), Patient’s Global Assessment VAS and Patient's Assessment of Joint Pain VAS reflected a high burden of illness. Conclusion The reported BL characteristics offer preliminary information about which pts initiate or switch to a b/tsDMARD in a real-life setting. Future disclosures (at 12 and 24M) will provide RWE regarding persistence, effectiveness, and healthcare resource use of available treatments for PsA, which will help pts and physicians to make better informed treatment decisions. Disclosure J. Morel: Consultancies; J. Morel has been a speaker and/or consultant for: AbbVie, Amgen, Biogen, Bristol Myers Squibb, Eli Lilly and Company, Fresenius, Galapagos, Glaxo Smith Kline, Médac, Novartis, Sandoz, and Sanofi. Grants/research support; J. Morel has received grant funding/research support from: Biogen, Bristol Myers Squibb, Eli Lilly and Company, Novartis, and Pfizer. L. Dagna: Consultancies; L. Dagna has been a speaker and/or consultant for: AbbVie, Amgen, AstraZeneca, Biogen, Bristol Myers Squibb, Celltrion, Lilly, Galapagos, GSK, Janssen, Kiniska, Pfizer, Roche, Sobi, and Sanofi. B. Ibañez: Grants/research support; B. Joven-Ibáñez has been a speaker for and has received grant funding/research support from: Eli Lilly and Company. T. Holzkaemper: Shareholder/stock ownership; T. Holzkaemper is a shareholder and employee of: Eli Lilly and Company. C. El Baou: Consultancies; C. El Baou has worked as a consultant for: Eli Lilly and Company. L. Unger: Other; L. Unger has been a speaker for: Eli Lilly and Company. A. Semeraro: None. N. Gullick: Consultancies; N. Gullick has been a speaker and/or consultant for: AbbVie, Celgene, Eli Lilly and Company, Janssen, Novartis, and UCB. Grants/research support; N. Gullick has received grant funding/research support from: AbbVie, AstraZeneca, Eli Lilly and Company, Izana, and Novartis. T. Treuer: Shareholder/stock ownership; T. Truer is a shareholder and employee of: Eli Lilly and Company.