Efficacy and safety of rituximab and low dosage of glucocorticoids for ANCA associated vasculitis interstitial lung disease: a proof-of-concept study

Introduction

The prevalence of interstitial lung disease (ILD) in ANCA associated vasculitis (AAV) ranges from 13 % to 45 %, and both its definition and management represent a quandary. The occurrence of lung fibrosis and ANCA positivity, particularly in subjects without any other evidence of vasculitis, is far from being clearly interpreted, as well as its proper therapeutic management. In this regard, aim of this study is to assess whether Rituximab (RTX) in association with a low dosage of glucocorticoids (GCs), could be effective also in the treatment of AAV-ILD.

Materials and methods

We prospectively included all patients referred to our multidisciplinary “Vasculitis with lung involvement clinic” from January 2022 to March 2023 with microscopic polyangiitis (MPA) or granulomatosis with polyangiitis (GPA), ANCA positivity and ILD. All patients were concomitantly evaluated by a rheumatologist and a pneumologist experienced in vasculitis and autoimmune-associated ILD. High resolution computed tomography (HRCT) of the chest was performed at baseline and then after 12 months, while lung function test (LFT), including diffusion lung capacity for CO (DLCO) assessment, at baseline and after 6 and 12 months. For induction of remission, patients were treated with RTX, administered with the two-dose protocol (1000 mg at baseline and after 14 days) approved for rheumatoid arthritis, followed by 500 mg every 6 months. GCs were prescribed and then tapered according to PEXIVAS trial.

Results

Eight patients, 3 affected by GPA and 5 by MPA, were included. All but one displayed positivity for anti-MPO and 3 of them did not have any extra-pulmonary sign of vasculitis. At baseline, LFT evidenced a restrictive pattern (mean FVC 83 %) associated with a moderate impairment of diffusion capacity (mean DLCO 54 %). After 6 and 12 months, a stabilization of LFT findings was evidenced, while no sign of progression of ILD was assessed at CT scan. No patient suffered from severe AE, except one who had bacterial pneumonia. All patients but three discontinued GCs.

Discussion

Ours represents the first prospective study specifically designed to evaluate the efficacy of RTX in AAV-ILD. Our findings have displayed that RTX, prescribed in association with a short course of GCs, is able to stabilize imaging features and respiratory functional parameters.