Idiopathic pulmonary fibrosis (IPF) is an entity of interstitial pneumonia that has an unfavorable prognosis; approximately 50% patients die within 2-5 years from diagnosis. No effective drugs were available for treating IPF until 2008, when a phase III trial conducted in Japan demonstrated that pirfenidone attenuated the decline in vital capacity (VC) and prolonged the progression-free survival in patients with mild-to-moderate IPF. In the CAPACITY 2 study conducted in 13 countries, pirfenidone was shown to significantly attenuate the decline in the percent change of forced vital capacity (FVC) in patients with mild-tomoderate IPF. Pirfenidone was approved for the treatment of IPF in Japan in 2008 and for the treatment of adult patients with mild-to-moderate IPF in the EU in 2011.