The effect of Rituximab treatment on progression of Rheumatoid arthritis-associated interstitial lung disease

Introduction: Interstitial lung disease (ILD) commonly occurs in the context of Rheumatoid arthritis (RA), and is associated with significant morbidity and mortality. Rituximab is commonly used in the treatment of articular Rheumatoid arthritis and has been shown to be safe in patients with ILD. Aims and objectives: We aimed to study the effect of Rituximab treatment on the progression of RA-ILD as measured by decline in FVC and TLCO. Methods: A retrospective analysis of patients with RA treated at a tertiary referral centre in the United Kingdom between November 2016 and November 2018 was performed. Patients with at least 3 months' follow up were included if they had at least two lung function tests performed. Decline was measured either from first administration of Rituximab or from first available lung function (no treatment group). Results: 44 patients were identified who met the study criteria. Patients had follow up of a median 23.5 (range 6-89) months. In the group treated with Rituximab, 9 of 26 patients (34.6%) progressed (defined by a decline in FVC of > 10% or TLCO of > 15% or death due to respiratory disease) at a median of 23 months (range 8-44). In the group that did not receive Rituximab, 11 of 18 patients (61.1%) had progression of disease at a median of 18 months (range 3-44). There was a trend towards significance (p=0.08) in rate of decline in FVC between the two groups favouring Rituximab. Conclusions: In patients with RA-ILD, Rituximab was associated with a slower rate of progression when measured by decline in lung function. This supports the use of Rituximab in the management RA-ILD and the development of robust trials.