PACIFIC (2017)

Locally advanced, unresectable stage III non-small cell lung cancer (NSCLC) has historically had poor long-term outcomes even after definitive chemoradiation. This study investigated whether consolidation immunotherapy with durvalumab could improve survival outcomes in this patient population.

The PACIFIC trial was a phase 3, randomized, double-blind, placebo-controlled study. Patients with unresectable stage III NSCLC who had not progressed after platinum-based chemoradiation were randomized 2:1 to receive durvalumab or placebo every 2 weeks for up to 12 months. The co-primary endpoints were progression-free survival (PFS) and overall survival (OS).

Durvalumab significantly improved both PFS and OS. The median PFS was 17.2 months with durvalumab versus 5.6 months with placebo (HR 0.51, P < 0.001). The median OS was not reached in the durvalumab group versus 28.7 months in the placebo group (HR 0.68, P = 0.0025). The 24-month OS rate was 66.3% with durvalumab versus 55.6% with placebo.

Consolidation durvalumab after definitive chemoradiation is the standard of care for patients with unresectable stage III NSCLC who have not progressed, significantly improving both PFS and OS.

The study excluded patients with rapid progression during chemoradiation. The long-term toxicity profile, especially with longer follow-up, and the optimal duration of therapy remain areas of ongoing research.