Three-Year Overall Survival with Durvalumab after Chemoradiotherapy in Stage III NSCLC—Update from PACIFIC

Introduction: In the phase 3 PACIFIC study of patients with unresectable stage III NSCLC without progression after chemoradiotherapy, durvalumab demonstrated significant improvements versus placebo in the primary end points of progression-free survival (hazard ratio [HR] = 0.52, 95% confidence interval [CI]: 0.42–65, p < 0.0001) and overall survival (OS) (HR = 0.68, 95% CI: 0.53–0.87, p = 0.00251), with manageable safety and no detrimental effect on patient-reported outcomes. Here, we report 3-year OS rates for all patients randomized in the PACIFIC study. Methods: Patients, stratified by age, sex, and smoking history, were randomized (2:1) to receive durvalumab, 10 mg/kg intravenously every 2 weeks, or placebo for up to 12 months. OS was analyzed by using a stratified log-rank test in the intention-to-treat population. Medians and rates at 12, 24, and 36 months were estimated by the Kaplan-Meier method. Results: As of January 31, 2019, 48.2% of patients had died (44.1% and 56.5% in the durvalumab and placebo groups, respectively). The median duration of follow-up was 33.3 months. The updated OS remained consistent with that previously reported (stratified HR = 0.69 [95% CI: 0.55–0.86]); the median OS was not reached with durvalumab but was 29.1 months with placebo. The 12-, 24- and 36-month OS rates with durvalumab and placebo were 83.1% versus 74.6%, 66.3% versus 55.3%, and 57.0% versus 43.5%, respectively. All secondary outcomes examined showed improvements consistent with previous analyses. Conclusions: Updated OS data from PACIFIC, including 3-year survival rates, demonstrate the long-term clinical benefit with durvalumab after chemoradiotherapy and further establish the PACIFIC regimen as the standard of care in this population.