SAT0203 Rituximab in Patients with Idiopathic Inflammatory Myopathies Associated with Interstitial Lung Disease

Background Interstitial lung disease (ILD) is the most common internal organ manifestation of idiopathic inflammatory myopathies (IIM) that can severely affect the course of the disease. IIM patients with ILD often show resistance to conventional treatment with glucocorticoids (GC) and cytotoxic drugs so addition of biologic agents is an interesting possibility. Objectives To assess efficacy and tolerability of rituximab (RTM) in IIM patients with ILD. Methods IIM patients fulfilling Bohan and Peter criteria and having ILD were followed up in the Nasonova Research Institute of Rheumatology from 2009 to 2015. RTM was administered in case of intolerance or inadequate response to GC and other immunosuppressive drugs. Manual muscle testing (MMT), dyspnea assessment according to NYHA, creatinkinase (CK) and anti-Jo-1 antibodies (anti-Jo-1) assay; forced vital capacity (FVC) and carbon monoxide diffusion capacity (DLCO) evaluation as well as high-resolution computed tomography (HRCT) scanning of the chest were performed at baseline, 6–12 and 18–24 months after inclusion. Results 41 patients (34 females, 7 males) with median age 50 [44;56], median disease duration 24 months [7;108] were included. 28 from them had decreased MMT value and class 1–2 NYHA dyspnea was present in 19. 18 patients were positive for anti-Jo-1 and 15 had elevated CK level. HRCT showed ILD signs including ground glass opacities (GGO) in all cases. FVC 10%, and 7 demonstrated DLCO increase by >10%. Worsening of pulmonary function tests was documented in 2 cases, while in the rest they were stable. After 18–24 months of follow up FVC remained +10% better vs baseline value in 10, DLCO – in 8 patients. In the rest patients these parameters remained stable. ILD was not progressing in 27 patients based on HRCT images in 6–12 months, moreover GGO lesions count was reduced in 10 patients, but there were cases of ILD worsening documented in 6 patients. Although, HRCT monitoring in 18–24 months showed ILD improvement in 7 patients and worsening – in 2, in remaining patients ILD was stable. Comorbid infections were documented in 18 patients, commonly manifesting in 2–3 months after the first RTM infusion. Conclusions RTM treatment allows to achieve stable disease without typical for this condition further progression of pulmonary lesions in the majority of IIM patients with ILD. Disclosure of Interest None declared