Connective tissue disease-associated interstitial lung disease treated with cyclophosphamide or rituximab: a unicentre, open-label and comparative study

Abstract

To date, rheumatologists do not have curative treatments for connective tissue disease-associated interstitial lung disease (CTD-ILD), and therefore, stabilization of the disease is considered a therapeutic success. One of the most frequently used drugs for achieving this goal is Cyclophosphamide (CYC); however, in recent years, there has been increasing interest in the use of Rituximab (RTX) as a treatment for CTD-ILD. The objective of this study was to compare the long-term effectiveness of CYC versus RTX as treatments for patients with CTD-ILD. This was a unicenter, retrospective study analyzing clinical and imaging data of 26 CTD-ILD patients treated with CYC or RTX between June 2004 and December 2016. Baseline characteristics and baseline levels of Pulmonary Function Tests (PFTs) in both groups were compared using Fisher and T-student tests to ensure they were similar. The primary outcome of the study was the stabilization of PFTs or High-Resolution Tomography Computed Tomography (HRCT), with relapse defined as: a) a deterioration of ≥10% in Forced Vital Capacity (FVC), b) a decrease of ≥15% in Diffusing Capacity of Carbon Monoxide (DLCO), or c) worsening in HRCT. The prognostic effect of each treatment on stabilization was evaluated using the Kaplan-Meier method and the Log-Rank test.