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.

Disclosure of Interests: None declared