Recent Topics in Treatment for Idiopathic Pulmonary Fibrosis

Abstract

Idiopathic pulmonary fibrosis (IPF) is a devastating and fatal disease of unknown etiology. Survival of IPF is estimated at 3 to 4 years from first medical assessment for idiopathic interstitial pneumonias (IIPs). Currently, available therapies for IPF include corticosteroid and immunosuppressant for anti-inflammatory actions unfortunately no improvements were noted for the survival of IPF. Recently, several clinical studies report on the antifibrotic outcomes for new agents of IPF. Pirfendione, Interferon (IFN)-γ, and N-acetylcysteine (NAC) are promising agents for IPF. We confirmed the efficacy of pirfenidone as a significant inhibitor for the deterioration of pulmonary functions and for decreasing the number of patients with acute exacerbations during a well designed, double blind placebo controlled randomized clinical trial in Japan. Furthermore, we adopted new methods for assessing dynamic pulmonary function by measuring minimum values of desaturation during 6 minutes walking at constant speed. Interstitial pneumonia in patients with Hermansky-Pudlak syndrome has been treated with pirfenidone in US. Pirfenidone successfully prevents worsening of %FVC for patients with %FVC>60%, but not for the group %FVC≤60%. Treatment with IFN-γ for IPF has been conducted in North America, but IFN-γ could not improve progression-free survival for the intent-to-treat group. However, IFN-γ significantly decreased the mortality ratio in patients with %FVC>60%. Recently, the evaluation of effective drugs for IPF has focused on dynamic pulmonary functions such as 6 minutes walk test, as pathological evaluation of IIPs is not recognized as a gold standard for estimating survival of patients with IPF. In this review, we introduce new strategies for the evaluation, and compounds for the treatment of IPF.