Objective: To examine the clinical aspects of idiopathic pulmonary fibrosis (IPF) and the efficacy and safety of interferon gamma-1b (IFNgamma-1b) in its treatment.
Data sources: Epidemiologic, preclinical, and clinical studies published in the English language were identified by a MEDLINE search (1966-January 2005) using the search terms idiopathic pulmonary fibrosis, cryptogenic fibrosing alveolitis, and interferon. Additional citations were identified from the reference lists of related publications.
Study selection and data extraction: Selected preclinical studies describing the pathophysiologic basis for IFNgamma-1b therapy and all clinical studies were included. Additional trials describing other treatment modalities and the determinants of response to therapy in patients with IPF were also reviewed.
Data synthesis: IFNgamma-1b targets the fibrotic rather than inflammatory processes of IPF. The efficacy of IFNgamma-1b in patients with IPF is inconsistent with regard to changes in pulmonary function and mortality, although a modest survival benefit was observed in the largest clinical trial. Adverse events related to IFNgamma-1b are frequent although transient. Several cases of respiratory failure occurring subsequent to the administration of IFNgamma-1b are documented.
Conclusions: To date, although trials suggest that earlier-stage IPF may be responsive to IFNgamma-1b, study results overall are inconsistent; further investigation is needed.