Roche has just announced the acquisition of the U.S. biotech company InterMune for $8.3 billion. The driver for Roche was to gain access to InterMune’s drug, pirfenidone (trade name, Esbriet), which is already approved in Canada and Europe for idiopathic pulmonary fibrosis (IPF). IPF is a deadly lung-scarring disease which affects 50,000 – 70,000 people in the U.S. and 80,000 to 110,000 in Europe. While still under review by U.S. regulatory authorities, Roche’s acquisition signals its belief that pirfenidone will also gain U.S. approval. How big a product can pirfenidone be? Consensus forecasts compiled by Thomson Reuters Pharma peg annual sales at greater than $1 billion in 2019 – a nice addition to Roche’s stable of pulmonary compounds including Xolair (asthma) and Pulmozyme (cystic fibrosis).