Background: Tumour necrosis factor inhibitors (TNFi) and Interleukin-17A inhibitors (IL-17Ai) have shown effectiveness in achieving low disease activity (LDA) in patients with axial spondyloarthritis (axSpA). However, the impact of prior TNFi treatment on the time required to achieve LDA and the duration of achieved LDA in subsequent TNFi or IL-17Ai treatment remains unknown.

Objectives: To assess the time to achieve LDA following the initiation of a TNFi or an IL-17Ai, as well as the duration of achieved LDA, in patients with axSpA stratified by prior exposure to 0, 1 or 2 TNFi treatments.

Methods: Patients initiating a TNFi or an IL-17Ai between 2017 and 2023 were included from 13 registries in the EuroSpA Research Collaboration. We excluded patients with LDA at treatment start or prior treatment with targeted synthetic disease-modifying anti-rheumatic drugs (tsDMARDs) or non-TNFi biological DMARDs. LDA was defined as the Axial Spondyloarthritis Disease Activity Score (ASDAS) < 2.1. Time to achieve LDA was defined as the number of weeks from treatment start to the first visit in LDA, and duration of LDA as the number of weeks between the first visit in LDA and the first subsequent visit not in LDA. Patients not achieving LDA during follow-up were censored at the last visit on treatment. Missing components of ASDAS were imputed by predictive mean matching, and analyses were performed in separate cohorts of patients initiating TNFi and IL-17Ai, stratified by the number of prior TNFi treatments (0/1/2). Means with standard deviation (SD) and adjusted Cox regression models with hazard ratios (HR) and 95% confidence intervals (CI) were applied to assess time to achieve LDA and duration of LDA and compare across strata.

Results: We included 15,428 and 2,430 patients initiating treatment with TNFi and IL-17Ai, respectively. Baseline characteristics were similar across groups apart from a higher proportion of bio-naïve patients (83% vs. 37%) in the TNFi cohort (Table 1). Mean (SD) time to achieve LDA across prior TNFi treatment (0/1/2) was 33 (43)/ 45 (57)/ 51 (62) weeks for the TNFi cohort and 40 (48)/ 39 (51)/ 46 (59) weeks for the IL-17Ai cohort. With bio-naïve patients as reference, HRs for achieving LDA with 1 and 2 prior TNFi were, respectively, 0.79 (95% CI 0.74-0.85) and 0.61 (95%CI 0.54-0.69) for TNFi, and 0.74 (95% CI 0.63-0.86) and 0.58 (95% CI 0.48-0.69) for IL-17Ai (Figure 1). The mean (SD) duration of LDA across prior TNFi treatments (0/1/2) was 58 (66)/ 60 (68)/ 55 (68) weeks for the TNFi cohort and 63 (62)/ 37 (46)/ 41 (50) weeks for the IL-17Ai cohort. With bio-naïve patients as reference, HRs for not maintaining LDA were, respectively, 1.10 (95% CI 0.99-1.22) and 1.10 (95% CI 0.92-1.32) for 1 and 2 prior TNFi in the TNFi cohort, and, respectively, 1.57 (95% CI 1.23-2.00) and 1.78 (95% CI 1.37-2.30) for 1 and 2 prior TNFi in the IL-17Ai cohort (Figure 1).

Conclusion: This large European real-world cohort of patients with axSpA demonstrated that the time to achieve LDA increased with the number of prior TNFi in both TNFi and IL-17Ai treatments. While the duration of LDA was shorter for TNFi-experienced than for bio-naïve patients initiating IL-17Ai, prior TNFi use did not affect the LDA duration in patients initiating TNFi therapy. More research is needed to investigate the underlying reasons for these findings.

REFERENCES: NIL.

Acknowledgements: The EuroSpA collaboration has been supported by Novartis Pharma AG since 2017 and UCB Biopharma SRL since 2022. This EuroSpA study was financially supported by UCB. No financial sponsors had any influence on the data collection, statistical analyses, abstract preparation, or decision to submit.

Disclosure of Interests: Jette Heberg Novartis (Grant/Research Support paid to employer) UCB (Grant/Research Support paid to employer), Stylianos Georgiadis Research grant from Novartis, Marion Pons Research grant from Novartis and UCB (paid to the employer), Anne Gitte Loft Novartis, UCB, Janssen, Novartis, UCB, Brigitte Michelsen Speaker’s fees from Novartis, Research grant from Novartis and Pfizer (paid to employer). Centre for Treatment of Rheumatic and Musculoskeletal Diseases (REMEDY) is funded as a Centre for Clinical Treatment Research by The Research Council of Norway (project 328657), Louise Linde Research grant from Novartis, Daniela Di Giuseppe: None declared, Simon Horskjær Rasmussen Research grant from Novartis, Mehrdad Shoae Kazemi Research grant from Novartis and UCB (paid to employer), Gary J. Macfarlane Research grant from GSK, Gareth T. Jones Janssen, UCB, Research grants (paid to employer) from AbbVie, Pfizer, UCB, Amgen, GSK, Menarini and Shionogi, Karin Laas Abbvie, Johnson and Johnson, Novartis, Pfizer, Sigrid Vorobjov: None declared, Isabel Castrejon BMS, Boehringer, Eli Lilly, Galapagos, Gebro, GSK, Janssen, Pfizer, UCB, Consultant for Alfasigma, Pfizer, UCB, Fernando Sánchez-Alonso: None declared, Ziga Rotar Abbvie, Amgen, Novartis, MSD, Medis, Biogen, Eli Lilly, Pfizer, Sanofi, Lek, Janssen, Abbvie, Novartis, Eli Lilly, Pfizer, Janssen, Sobi, Swixx BioPharma, AstraZeneca, Katja Perdan Pirkmajer Abbvie, Novartis, MSD, Medis, Eli Lilly, Pfizer, Lek, Sobi, Boehringer Ingelheim, Abbvie, Novartis, Medis, Eli Lilly, Pfizer, Boehringer Ingelheim, Stada, Sobi, Ladislav Šenolt Abbvie, Bristol-Myers Squibb, Eli Lilly, Janssen, Merck Sharp and Dohme, Novartis, Pfizer, Sandoz, Sanofi-Aventis, Swedish Orphan Biovitrum, UCB, Abbvie, Bristol-Myers Squibb, Eli Lilly, Janssen, Merck Sharp and Dohme, Novartis, Pfizer, Sandoz, Sanofi-Aventis, Swedish Orphan Biovitrum, UCB, Jana Baranová: None declared, Bente Glintborg Research grants from Pfizer, Abbvie, BMS, Sandoz, Adrian Ciurea: None declared, Miguel Bernardes Advisory board and/or speaker fees from AbbVie, Janssen, GSK, AstraZeneca, Pfizer, Advisory board and/or speaker fees from AbbVie, Janssen, GSK, AstraZeneca, Pfizer, Paula Valente: None declared, Bjorn Gudbjornsson: None declared, Gerdur Grondal: None declared, Gunnstein Bakland Novartis, Johnson&Johnsen, UCB, Catalin Codreanu AbbVie, Amgen, AstraZeneca, Boehringer Ingelheim, Ewopharma, Lilly, Novartis, Pfizer, Sandoz, Sobi, AbbVie, Amgen, Boehringer Ingelheim, Lilly, Novartis, Pfizer, Sobi, Corina Mogosan speaker fees from UCB, Pfizer, Sella Aarrestad Provan Boehringer Ingelheim, Boehringer Ingelheim, Florenzo Iannone consulting and/or speaking from Abbvie, Amgen, AstraZeneca, BMS, Galapagos, Janssen, Lilly, MSD, Novartis, Pfizer, UCB, consulting and/or speaking from Abbvie, Amgen, AstraZeneca, BMS, Galapagos, Janssen, Lilly, MSD, Novartis, Pfizer, UCB, Research grant from BMS, Galapagos, Pfizer, Roberto F. Caporali consulting and/or speaking from Abbvie, Amgen, AstraZeneca, BMS, Galapagos, Janssen, Lilly, MSD, Novartis, Pfizer, Roche, UCB, Johan K Wallman Speaker fees from AbbVie, Amgen, Research support from AbbVie, Amgen, Eli Lilly, Novartis, Pfizer, Vappu Rantalaiho Abbvie, BMS, Novartis, Viatris, Johnson&Johnson, Lilly, Ritva Peltomaa Abbvie, Boehringer Ingelheim, Celltrion, Fresenius, Janssen, Lilly, UCB, Galapacos, Karel Pavelka Speaker fees from AbbVie, Amgen, Pfizer, Eli Lilly, Viatris, Fresenius, Novartis, AbbVie, UCB, Pfizer, Eli Lilly, Celltrion, MSD, and Novartis, Pavel Horak Abbvie, Bristol-Myers Squibb, Eli Lilly, Janssen, Merck Sharp and Dohme, Novartis, Pfizer, Sandoz, Sanofi-Aventis, Swedish Orphan Biovitrum, UCB, Abbvie, Bristol-Myers Squibb, Eli Lilly, Janssen, Merck Sharp and Dohme, Novartis, Pfizer, Sandoz, Sanofi-Aventis, Swedish Orphan Biovitrum, UCB, Diogo Esperança Almeida: None declared, Sara Dias Rodrigues: None declared, Lykke Midtbøll Ørnbjerg Research grant from Novartis, Mikkel Østergaard Abbvie, BMS, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Gilead, Hospira, Janssen, MEDAC, Merck, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB, Abbvie, BMS, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Gilead, Hospira, Janssen, MEDAC, Merck, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB, AbbVie, Amgen, BMS, Merck, Celgene, Eli Lilly, Novartis, and UCB, Merete Lund Hetland Speaker for Pfizer, Medac, Sandoz (no personal income, institution); speaker for Novartis (personal income), Advisory Board Abbvie (No personal income, paid to institution). Prev. chaired the steering committee of the Danish Rheumatology Quality Registry (DANBIO, DRQ), which receives public funding from the hospital owners and funding from pharmaceutical companies, Research grants (institution) from Abbvie, Biogen, BMS, Celltrion, Eli Lilly, Janssen Biologics B.V, Lundbeck Fonden, MSD, Medac, Pfizer, Roche, Samsung Biopies, Sandoz, Novartis, Nordforsk.

© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.