Clinical experience with antifibrotics in fibrotic hypersensitivity pneumonitis: a 3-year real-life observational...

Fibrotic hypersensitivity pneumonitis (f-HP) can exhibit a progressive course similar to idiopathic pulmonary fibrosis (IPF). The lack of diagnostic guidelines and randomised controlled trials in this population represent a significant unmet need.

To describe our clinical experience with antifibrotics in patients with f-HP.

Retrospective study of 30 patients diagnosed with f-HP upon re-evaluation within a multidisciplinary team discussion of 295 consecutive patients (January 2012 to December 2017) who had been diagnosed initially with IPF at outside facilities and were referred to our centres.

Pirfenidone was initially administered to 14 (46.7%) patients and nintedanib to 16 (53.3%) patients. There were 26 (86.7%) males, with mean±sd age 70.2±8.4 years. The annual rate of decline in forced vital capacity (FVC) % predicted over the 3-year treatment period adjusted for baseline FVC % pred measurement was 4.2% (95% CI 1.9-6.6%, p=0.001) and 7.5% (95% CI 3.3-11.7%; p=0.001) in imputation analysis. The annual rate of decline in diffusing capacity of the lung for carbon monoxide (D _LCO) % predicted throughout the 3-year treatment period adjusted for baseline D _LCO % pred was 5.7% (95% CI 3.1-8.4%, p<0.001) and 5.8% (95% CI 3.4-8.1%, p<0.001) in imputation analysis. The nature of adverse events was related to the type of antifibrotic agent administered.

In patients with f-HP receiving antifibrotics there is a statistically significant annual decline in FVC % pred and D _LCO % pred over a period of 3 years. Prospective randomised trials exceeding 1 year are warranted to determine the long-term efficacy of antifibrotics.