ABSTRACT
BACKGROUND: Evidence on abatacept (ABA) utility for rheumatoid arthritis (RA) - associated interstitial lung disease (ILD) is growing. Clinical trials have shown equivalence in subcutaneous (SC) and intravenous (IV) administration of ABA for articular manifestations. However, this has not been studied in respiratory outcomes. OBJECTIVE: To compare the effectiveness of ABA in RA-ILD patients according to the route of administration. METHODS: National retrospective multicentre study of RA-ILD patients on treatment with ABA. They were divided into 2 groups: a) IV, and b) SC. The following outcomes were analysed from baseline to final follow-up using linear mixed models: a) forced vital capacity (FVC), b) diffusing capacity of the lungs for carbon monoxide (DLCO), c) chest high resolution computed tomography (HRCT), d) dyspnoea, e) RA activity, and f) sparing corticosteroids effect. RESULTS: A total of 397 patients were included (94 IV-ABA and 303 SC-ABA), median follow-up of 24 [10-48] months. After adjustment for possible confounders, FVC and DLCO remained stable during the first 24 months without differences between IV-ABA and SC-ABA (p = 0.6304 and 0.5337). Improvement/ stability of lung lesions in HRCT was observed in 67 % of patients (75 % IV-ABA, 64 % SC-ABA; p = 0.07). Dyspnoea stabilized/ improved in 84 % of patients (90 % IV-ABA, 82 % SC-ABA; p = 0.09). RA - disease activity improved in both groups. No statistically significant differences regarding any of the variables studied between the two groups were found. ABA was withdrawn in 87 patients (21.9 %), 45 % IV-ABA and 37 % SC-ABA (p = 0.29). ILD worsening and articular inefficacy were the most common reasons for ABA discontinuation. CONCLUSION: In patients with RA-ILD, ABA seems to be equally effective regardless of the route of administration.