POS0595 ABATACEPT IN USUAL AND IN NON-SPECIFIC INTERSTITIAL PNEUMONIA ASSOCIATED TO RHEUMATOID ARTHRITIS. NATIONAL MULTICENTER STUDY OF 190 PATIENTS

Background: Interstitial lung disease (ILD) is a severe complication of Rheumatoid Arthritis (RA). Usual interstitial pneumonia (UIP) is considered to be more frequent and severe in RA than non-specific interstitial pneumonia (NSIP). Abatacept (ABA) and Rituximab have demonstrated efficacy in RA-ILD [1-3]. Objectives: To compare the efficacy of ABA in RA-ILD patients according to radiological patterns of UIP or NSIP. Methods: From an observational multicenter study of 263 RA-ILD patients treated with ABA, we selected those with UIP or NSIP [2]. We analyzed in the 2 groups from baseline up to 24 months the following outcomes: a) Forced Vital Capacity (FVC), b) Carbon monoxide diffusing capacity (DLCO), c) Chest High Resolution Computed Tomography (HRCT), and d) dyspnea. Differences between final follow-up and basal visit were calculated as the average difference and 95% Confidence Interval (95% CI). Multivariable linear regression was used to assess the differences between the 2 groups. Results: We studied 190 patients with UIP (n=106) and NSIP (n=84). Patients with UIP were older, had more positivity for rheumatoid factor and had received more sulfasalazine (Table 1). ILD duration up to ABA initiation was relatively short in both groups, with a median [IQR] of 16 [4-50] and 11 [2-36] months in UIP and NSIP patterns, respectively. Mean baseline values of FVC and DLCO were > 80% and > 60%, respectively, in the 2 groups, with a lower FVC in UIP (82% vs 89% in NSIP, p Conclusion: ABA seems to be equally effective in stabilizing of DLCO, FVC and HRCT in UIP and NSIP in RA-ILD. Our results suggest that an early administration of ABA in ILD, before significant structural lung damage development, may be preferable to prevent interstitial progression, regardless of the radiological pattern. References: [1]Fernandez-Diaz C, et al. Semin Arthritis Rheum. 2018 Aug;48(1):22-27. doi: 10.1016/j.semarthrit.2017.12.012 [2]Fernandez-Diaz C, et al. Rheumatology (Oxford). 2020 Dec 1;59(12):3906-3916. doi: 10.1093/rheumatology/keaa621 [3]Atienza-Mateo B, et al. J Clin Med. 2020 Sep 23;9(10):3070. doi: 10.3390/jcm9103070 Acknowledgements: the Spanish Collaborative Group of Abatacept in Interstitial Lung Disease Associated with Rheumatoid Arthritis Disclosure of Interests: Belen Atienza-Mateo: None declared, Carlos Fernandez-Diaz Speakers bureau: Brystol Myers Squibb, Santos Castaneda: None declared, Rafael Melero: None declared, FRANCISCO ORTIZ SANJUAN: None declared, Ivette Casafont-Sole: None declared, Sebastian C Rodriguez-Garcia: None declared, Ivan Ferraz-Amaro: None declared, Miguel A Gonzalez-Gay: None declared, Ricardo Blanco Speakers bureau: Brystol Myers Squibb