POS0597 EFFECTS OF RITUXIMAB IN PATIENTS WITH RHEUMATOID ARTHRITIS-RELATED INTERSTITIAL LUNG DISEASE: A SINGLE-CENTRE EXPERIENCE FROM TURKEY
Authors: D. Sahin Eroglu, A. Colaklar, S. Baysal, M. Torgutalp, A. Baygul, M. E. Yayla, T. M. Turgay, G. Kinikli, A. Ates
Journal: Annals of the Rheumatic Diseases (2021)

Background: Rheumatoid arthritis-related interstitial lung disease (RA-ILD) is the most common type of lung involvement in rheumatoid arthritis (RA). The existence of RA-ILD is associated with worse survival. There is no mainstay treatment for RA-ILD. However, in recent studies, rituximab (RTX) seems to be effective in RA-ILD. Objectives: To determine the effects of RTX in patients with RA-ILD from a single-centre. Methods: In our biological treatment outpatient clinic, a retrospective study was conducted in patients with RA who were treated with RTX. Among them, patients with RA-ILD were analysed. For lung response to RTX, progression was defined as a decline of 10% ≥ in forced vital capacity (FVC) and/or a decline of 15% ≥ in diffusion capacity of carbon monoxide (DLCO). Computed tomography of the chest (chest-CT) were integrated to lung response so as to constitute missing data of pulmonary function tests (PFTs). Results: A total of 165 patients who are followed-up in our biological treatment outpatient clinic have been using RTX for their RA diagnosis. Among 165 patients, 26 (15.8%) patients with RA-ILD were initiated RTX. Five patients were diagnosed with RA-ILD while using RTX (incidence rate 3%). Patients‘ characteristics were demonstrated in table 1. Of 26 patients, the most commonly used concomitant disease-modifying antirheumatic drugs was leflunomide (46.2%) followed by mycophenolate mofetil (11.5), methotrexate (11.5%) and azathioprine (3.8%). Twenty-four (92.3%) patients used steroids. For the evaluation of lung response, 20 patients who had follow-up PFTs and/or chest-CT were compared. Median DLCO values for pre- and post RTX were 71.0% (60.0-77.0) and 63.0% (47.0-74.0), respectively (p= 0.061). Median pre and post-RTX FVC were 74.0% (61.0-99.0) and 84.0% (63.0-100.0), respectively (p= 0.28). After a median of 2.7 years, 11 (55.0%) patients had stable disease, 2 (10.0%) patients had regression of RA-ILD and 7 (35.0%) patients had progressive disease. Sex, age, seropositivity and radiographic patterns were not associated with progression. In total, 23 adverse events were detected in 11 (42.3%) patients. Five of them were serious infections requiring hospitalization, mostly pneumonia. Other adverse events were simple infections and surgeries such as arthroplasty. RTX was stopped in 4 (15.4%) patients due to infections secondary to hypogammaglobulinemia in 2, malignancy in 1 and allergic reaction in 1. Conclusion: RTX seems to achieve stabilization/improvement of RA-ILD with fewer adverse events. However, given that RA-ILD develops post-RTX, it is not a panacea; therefore, we need more effective treatment modalities in the case of RA-ILD. Table 1. Characteristics of 26 patients with RA-ILD treated with rituximab Age at first RTX infusion, median (IQR), years 61.2 (57.1-65.1) RA disease duration at first RTX, median (IQR), years 10.1 (4.3-29.7) ILD disease duration at first RTX, median (IQR), years 1.9 (0.1-4.5) Age at RA diagnosis, median (IQR), years 51.1 (40.0-60.6) Age at ILD diagnosis, median (IQR), years 58.3 (53.9-63.3) Male patient, n (%) 16 (61.5) RF positivity, n (%) 25 (96.2) ACPA positivity, n (%) 20 (90.9) CRP levels,mg/L, mean (SD) 40.3 (58.9) ESR levels, mean (SD) 37.7 (18.2) Smoking status, n (%) 16 (64.0) Prior TNF inhibitor treatment, n (%) 5 (19.2) DAS28 at first RTX infusion, mean (SD) 5.3 (1.5) Radiographic pattern, n (%) UIP 7 (26.9) NSIP 8 (30.8) OP 2 (7.7) Indeterminate 8 (30.8) Others 1 (3.8) Follow-up duration, median (IQR), years 2.5 (1.2-3.7) RA-ILD= Rheumatoid arthritis-related interstitial lung disease, RTX= rituximab, RA= rheumatoid arthritis, RF= rheumatoid factor, ACPA= anti-citrullinated protein antibody, TNF= tumor necrosis factor, CRP= C-reactive protein, ESR= erythrocyte sedimentation rate, UIP= usual interstitial pneumonia, NSIP= non-specific interstitial pneumonia, OP= organizing pneumonia Disclosure of Interests: None declared