AB0800 Safety and clinical response to rituximab in patients with connective tissue disease-associated interstitial lung disease: Preliminary results

Background Rituximab may benefit patients with connective tissue diseases (CTD). Objectives We present here short-term safety and clinical outcomes of rituximab in CTD-associated interstitial lung disease (ILD) in a real-life clinical setting. Methods All patients with CTD-associated ILD treated with rituximab in our ILD clinic were included. Efficacy was assessed by pulmonary function tests and high-resolution computed tomography (HRCT). Results are expressed as median (limits). ILD exacerbations and safety were assessed. Results A total of 14 patients with CTD-associated ILD (29% rheumatoid arthritis, 21% primary Sjögren syndrome, 21% unclassifiable CTD, 14% systemic sclerosis and 14% inflammatory myopathy) received a dose of 4000 (2000 – 6000) mg Rituximab over an observation period of 161 patient-year. The distribution of morphologic ILD patterns were: 57% usual interstitial pneumonia (UIP), 21% unclassifiable ILD, 7% nonspecific interstitial pneumonia (NSIP), 7% cryptogenic organizing pneumonia (COP) and 7% lymphoid interstitial pneumonia (LIP). At baseline, IgG levels and leukocyte subset counts were within normal range, with reduced numbers of unswitched memory B cells. Incidence infection rate during RTX therapy was 4.35/100 patient-month with only one case being severe. There was 1 death, due to neutropenia with a disseminated fungal infection. Longitudinal pulmonary function data available in 12 patients showed an overall improvement in FVC (85%±19 versus 73%±18) and DLCO (58%±18 versus 45%±19). Radiographic progression could be evaluated in 6 patients, with five showing lack of progression and one improvement. ILD incidence relapse rate during rituximab therapy was 0.745/100 patient-month compared to 5.56/100 patient-month during the pre-treatment period. Conclusions Our preliminary data indicate that rituximab is safe in the study population. Our patients had a notoriously low exacerbation rate. Although optimal outcome measures in the short term are difficult to establish, we could confirm disease stabilization in most patients. Disclosure of Interest None Declared