Clinical Trials
Numerous well powered, prospective, randomized, placebo-controlled double-blind studies have been performed for IPF over the past decade ( Table 3 ). However, with the exception of the trial of pirfenidone in Japan, the phase 3 CAPACITY 004 pirfenidone trial, and the phase 2 TOMORROW study (BIBF 1120), primary endpoints have not been met. Additionally, most IPF studies have allowed limited use of corticosteroids in the 'placebo' arm. Lessons learned from various trials include the importance of including a true placebo arm and the pitfalls of using posthoc data analyses to draw conclusions concerning efficacy. Although posthoc analysis of the GIPF-1 study of interferon (IFN)-g1b suggested benefit for patients with less severe physiologic impairment, themore robustly powered INSPIRE trial showed no benefit for IFN-γ 1b as an antifibrotic therapy for IPF. Many newer agents with antifibrotic activity are now entering phase 1 and 2 clinical trials.