Baricitinib and the Risk of Incident Interstitial Lung Disease: A Descriptive Clinical Case Report from Clinical Trials

Objectives: Interstitial lung disease (ILD) occurs in up to 30% of patients with rheumatoid arthritis (RA), resulting in increased morbidity and death in the absence of proven therapies. The aim of this study is to estimate the number of incident ILD cases reported through development studies with baricitinib in patients with RA. Methods: Estimates were based on 3770 patients with RA from eight randomized clinical trials (four phase 3, three phase 2, one phase 1b) and one long-term extension study on baricitinib for which ILD was not an exclusion criterion with 12,358 patient-years of exposure (PYE). Results: Twenty-one non-infectious cases of ILD were reported with an exposure-adjusted incidence rate (EAIR) of 0.17 per 100 PYE. Of the 21 cases, six were reported as serious and 15 as non-serious resulting in an incidence rate of 0.05 per 100 PYE and 0.12 per 100 PYE, respectively. There were also 11 cases caused by an infectious agent: seven serious (IR: 0.06 per 100 PYE) and four non-serious cases (IR: 0.03 per 100 PYE). Conclusions: The findings of this analysis in patients with RA treated with baricitinib are consistent with a low risk to develop non-infectious ILD during baricitinib treatment, similar to that observed with other Janus kinase inhibitors.