SAT0154 STABILIZATION OF RHEUMATOID ARTHRITIS ASSOCIATED INTERSTITIAL LUNG DISEASEBY RITUXIMAB: A SINGLE CENTER EXPERIENCE WITH LONG-TERM FOLLOW-UP

Abstract

Background: Interstitial lung disease (ILD) is the most significant pulmonary manifestation of Rheumatoid Arthritis (RA)[1], contributing to decreased quality of life, progressive chronic disability and high utilization of healthcare resources. Treatment is challenging with mixed results from different biologics while Rituximab (RTX) has the most encouraging data based on retrospective observational studies. [2] Objectives: To evaluate the efficacy and safety of RTX in patients with RA-ILD in the context of daily practice. Methods: Observational retrospective study (2009-2019) of patients with a diagnosis of RA-ILD from a cohort of RTX-treated RA patients in the University Hospital of Heraklion. ILD was diagnosed by HRCT and monitored by means of pulmonary function tests (PFTs), HRCT and 6-minute walking test (6MWT, clinically important difference>50 m). RTX was used at standard dose (1 gr x2/6 months). ILD progression was defined by any of: decrease of pre-RTX forced vital capacity (FVC) >10%, or diffusion capacity of carbon monoxide (DLCO) >15% predicted score, or death from progressive ILD. Improvement was defined by any of: increase of pre-RTX FVC >10% or DLCO >15% predicted. All other patients were classified as having stable disease. RA activity was assessed by DAS28 (ESR). Results: Of 247 RA patients treated with RTX, 16 (11 women, 5 men) had RA-ILD (prevalence 6.5%). 12/16 (75%) had radiographic pattern of UIP and 4/16 (25%) had NSIP. 9/16 (56%) were positive for ACPA and/or RF. The median (IQR) age at RTX initiation was 66 (54-77) years, ILD duration prior to RTX was 5.2 (1-15) years. Number of prior biologics was 1 ± 4 and 11/16 (69%) have been treated with concomitant DMARDs. 1/16 (6.25%) had previously received Cyclophosphamide. Concomitant COPD was present in 3/16 (19%) of the patients. Follow-up while on RTX was 37 (6-136) months. The overall dose of RTX was 13 (2-40) g. Following RTX treatment, new-onset ILD was diagnosed in 3/247 patients (incidence=1.2%). During follow-up, data for ILD were available for 13/16 patients. Post-RTX, 10/13(76%) showed stabilization, 1/13(7.7%) had improvement, while 2/13(15.3%) had progression of RA-ILD. 1/16(6.25%) switched to Cyclophosphamide. During follow-up period, 6 admissions were recorded due to infections (4 for community-acquired pneumonia and 2 for hospital-acquired pneumonia) and 1/16(6.25%) patient died after progression of ILD. Conclusion: In this cohort of RA-ILD, the majority of patients treated with RTX showed stabilization of lung disease, while RA improved significantly, over a prolonged follow-up period. RTX appears to be an acceptable and safe therapeutic choice for patients with RA-ILD. Nevertheless, randomized studies are warranted to prove any clinical effectiveness of RTX in RA-ILD.