POS0513 ABATACEPT IN MONOTHERAPY VERSUS COMBINED IN INTERSTITIAL LUNG DISEASE OF RHEUMATOID ARTHRITIS. MULTICENTER STUDY OF 263 CAUCASIAN PATIENTS

Background:Interstitial lung disease (ILD) is a severe complication of RA. Abatacept (ABA) have demonstrated efficacy in RA-ILD [1,2], although combined treatment with MTX or others DMARDs remain controversial.Objectives:To assess the efficacy and safety of ABA in monotherapy (ABAMONO) versus combined-ABA, ABA plus MTX(ABAMTX) or ABA plus other non-MTX DMARDs (ABANON-MTX), in RA-ILD.Methods:Observational multicenter study of RA-ILD caucasian patients treated with ABA. We analyzed in three groups (ABAMONO, ABAMTX, ABANON-MTX) the following outcomes: a) Dyspnea, b) FVC and DLCO, c) HRCT, d) DAS28-ESR, e) corticosteroid-sparing effect. Differences between basal and final follow-up were evaluated. Multivariable linear regression was used between the three groups.Results:We studied 263 RA-ILD patients (mean age 64.6±10 years) [ABAMONO (n=111), ABAMTX (n=46) and ABANON-MTX (n=106)]. At baseline, ABAMONO patients were older (67±10 years) and took higher prednisone dose (10 [IQR 5-15] mg/day). There was no statistically significant differences in sex, seropositivity, ILD patterns, FVC, DLCO or disease duration. In all groups, most patients experienced stabilization or improvement in FVC, DLCO, dyspnea, HRCT as well as improvement in DAS28-ESR. A statistically significant difference between basal and final follow-up was only found in corticosteroid-sparing effect in ABAMTX or ABANON-MTX(Figure 1). However, in the multivariable analysis, there were no differences in any outcome between the three groups(Table 1).Table 1.Effect in FVC, DLCO, dyspnea (mMRC) and HRCT pulmonary scan after abatacept.ABAMONON=111ABAMTXN=46ABANON-MTXN=106ABAMTXvs ABAMONOABANON-MTXvs ABAMONOpppp*UnadjustedAdjusted**UnadjustedAdjusted**Follow-up, median [IQR] months12 [6-36]12 [6-36]18[12-36]0.400.670.17Differences between basal and final follow-upFVC, %-0.5 (-2.5, 1.5)0.641.2(-0.6, 3.1)0.17-1.2 (-2.9, 0.5)0.170.330.300.390.590.90DLCO, %1.8 (-0.7, 4.34)0.160.5 (-3.8, 4.8)0.82-1.5 (-4.1, 1.1)0.260.200.580.800.070.32mMRC, n (%)Worsening5 (5)3 (8)5 (5)0.830.470.99Stable or improving93 (95)36 (92)87 (95)HRCT pulmonary scan, n (%)Worsening13 (28)2 (11)15 (25)0.240.100.78Stable or improving34 (72)19 (89)44 (75)DAS28-ESR-1.5 (-1.9, -1.0)0.000-1.2 (-1.8, -0.6)0.000-1.5 (-1.8, -1.2)0.0000.740.580.92Prednisone, mg/day-3.8 (-8.3, 0.8)0.10-2.7 (-4.6, -0.8)0.006-4.8 (-6.3, -3.4)0.0000.690.670.65Differences in DAS28-ESR, prednisone, FVC and DLCO are expressed as mean difference (95%CI) comparing final follow-up minus basal values.*Differences between the 3 groups.**Differences between ABAMTX vs. ABAMONO, and between ABANON-MTX vs ABAMONO are adjusted for age, disease duration until abatacept treatment, and DAS28 and prednisone dose at baseline.Abbreviations(DAS28-ESR: Disease activity score-erythrocyte sedimentation rate; DLCO: Carbon Monoxide Diffusing Capacity; HRCT: High resolution computed tomography; FVC: Forced vital capacity, mMRC: modified Medical Research Council scaleFigure 1.Conclusion:In caucasian individuals with RA-ILD, ABAMONO or ABAMTX or ABANON-MTX seems to be equally effective and safe. However, a corticosteroid-sparing effect is only observed in combined-ABA.References:[1]Fernández-Díaz C, et al. Abatacept in patients with rheumatoid arthritis and interstitial lung disease: A national multicenter study of 63 patients. Semin Arthritis Rheum. 2018 Aug;48(1):22-27. doi: 10.1016/j.semarthrit.2017.12.012.[2]Fernández-Díaz C, et al. Abatacept in interstitial lung disease associated with rheumatoid arthritis: national multicenter study of 263 patients. Rheumatology (Oxford). 2020 Dec 1;59(12):3906-3916. doi: 10.1093/rheumatology/keaa621.Acknowledgements:Spanish Collaborative Group of Interstitial Lung Disease Associated to Rheumatoid ArthritisDisclosure of Interests:Carlos Fernández-Díaz Speakers bureau: Roche, bristol myers squibb, Belén Atienza-Mateo: None declared, Santos Castañeda: None declared, Rafael Melero: None declared, Francisco Ortiz-Sanjuán: None declared, Ivette Casafont-Solé: None declared, J. Loricera: None declared, Sebastián C Rodriguez-García: None declared, Iván Ferraz-Amaro: None declared, Miguel A González-Gay: None declared, Ricardo Blanco Speakers bureau: bristol myers squibb