Antonia SJ, et al — Researchers conducted an interim analysis of the PACIFIC study to determine if durvalumab offered any clinical benefit to patients with stage III, locally advanced unresectable non–small-cell lung cancer (NSCLC) that had not progressed after platinum-based chemoradiotherapy. This analysis found a significant increase in the primary endpoint of progression free survival among patients receiving durvalumab over those who received placebo. This benefit was seen across all subgroups with improvement also seen in all secondary endpoints. Side effects with durvalumab in this population are manageable and similar to those of other immunotherapies.

Methods:

• Patients were randomly assigned in a 2:1 ratio to receive durvalumab (at a dose of 10 mg per kilogram of body weight intravenously) or placebo every 2 weeks for up to 12 months
  
• The study drug was administered 1 to 42 days after the patients received chemoradiotherapy

Results:

• Median progression-free survival from randomization was 16.8 months with durvalumab vs 5.6 months with placebo
• Progression-free survival rate at 12 months was 55.9% vs 35.3%, and 44.2% vs 27.0% at 18 months
• Response rate with durvalumab was 28.4% vs 16.0% with placebo
• Median duration of response was longer with durvalumab, with 72.8% of patients having an ongoing response at 18 months vs 46.8% with placebo
• Grade 3 or 4 adverse events occurred in 29.9% of patients who received durvalumab vs 26.1% of those who received placebo, with pneumonia being the most common