Clinical trials and tribulations--lessons from pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a dreadful disease that lacks adequate therapy. A number of treatment trials have been performed and have utilized a variety of primary efficacy endpoints. Endpoints that provide the most useful efficacy information are clinical endpoints that are directly related to how a patient feels, functions or survives. Unfortunately, there are no properly established patient-reported outcome measures or measures of functional status in IPF, making survival the most robust primary efficacy endpoint. Clinically meaningful events such as hospitalization can also provide important efficacy information. The use of non-validated surrogate endpoints as primary outcome measures often leads to uncertainty when interpreting trial results.