Efficacy and Safety of Rituximab in Autoimmune Disease-Associated Interstitial Lung Disease: A Prospective Cohort Study

Objectives: To analyze the efficacy and safety of rituximab (RTX) in connective tissue disease associated with interstitial lung disease (CTD-ILD). Methods: We performed a multicenter, prospective, observational study of patients with CTD-ILD receiving rituximab between 2015 and 2020. The patients were assessed using high-resolution computed tomography and pulmonary function tests at baseline, at 12 months, and at the end of follow-up. The main outcome measure at the end of follow-up was forced vital capacity (FVC) > 10% or diffusing capacity of the lungs for carbon monoxide (DLCO) > 15% and radiological progression or death. We recorded clinical characteristics, time to initiation of RTX, concomitant treatment, infections, and hospitalization. A Cox regression analysis was performed to identify factors associated with worsening ILD. Results: We included 37 patients with CTD-ILD treated with RTX for a median (IQR) of 38.2 (17.7-69.0) months. At the end of the follow-up, disease had improved or stabilized in 23 patients (62.1%) and worsened in seven (18.9%); seven patients (18.9%) died. No significant decline was observed in median FVC (72.2 vs. 70.8; p = 0.530) or DLCO (55.9 vs. 52.2; p = 0.100). The multivariate analysis showed the independent predictors for worsening of CTD-ILD to be baseline DLCO (OR (95% CI), 0.904 (0.8-0.9); p = 0.015), time to initiation of RTX (1.01 (1.001-1.02); p = 0.029), and mycophenolate (0.202 (0.04-0.8); p = 0.034). Only 28 of the 37 patients (75.6%) were still undergoing treatment with RTX: two patients (5.4%) stopped treatment due to adverse events and seven patients (18.9%) died owing to progression of ILD and superinfection. Conclusion: Lung function improved or stabilized in more than half of patients with CTD-ILD treated with RTX. Early treatment and combination with mycophenolate could reduce the risk of progression of ILD.

Automated summary

The study showed that in patients with connective tissue disease associated interstitial lung disease treated with rituximab, over half of the patients showed improvement or stabilization of the disease at the end of follow-up. Early treatment and combination with mycophenolate could reduce the risk of ILD progression.