Bottom Line: A new analysis of survival data for the randomized, phase III PACIFIC trial finds adding the immunotherapy cancer drug durvalumab to radiation and chemotherapy significantly decreased the recurrence of lung cancer both in the chest area and in distant sites outside the chest. The updated PACIFIC trial data will be presented at the 61st Annual Meeting of the American Society for Radiation Oncology (ASTRO), by Andreas Rimner, MD, radiation oncologist, Memorial Sloan Kettering Cancer Center.
Background: Initial PACIFIC trial results showed that adding durvalumab after radiation and chemotherapy extended the time patients with stage III unresectable non-small cell lung cancer (NSCLC) lived without disease progression and significantly improved overall survival rates. As a result of these findings, adjuvant durvalumab became the new standard of care for patients whose disease had not progressed after concurrent platinum-based chemotherapy and radiation.
Findings: In an evaluation of 713 patients who were randomized to receive durvalumab (476) or a placebo (237) after completing radiation and chemotherapy, 45.4 percent and 64.6 percent, respectively, had disease progression at 18 months. While most patients experienced their first progression inside the chest area regardless of treatment arm, fewer patients receiving durvalumab experienced local and/or distant progression. Local-only progression occurred in 36.6 percent (durvalumab) and 48.1 percent (placebo) and distant-only progression occurred in 6.9 percent (durvalumab) and 13.1 percent (placebo). Median time to first local progression was improved on durvalumab (25.2 months versus 9.2 months). Median time to first distant progression was not reached in either group. When the disease did spread beyond the chest area, most new distant lesions occurred in a single organ. The most common site at progression was the brain.
Expert Comment: “These data represent a significant step forward as they continue to confirm the benefits of adding durvalumab to the treatment regimen for this patient population,” explained Dr. Rimner. “Because the cancer frequently did not recur in a widespread manner throughout the body, findings suggest that some of these patients may be treated with aggressive local therapies, such as radiation or surgery, at the time of recurrence. There is emerging evidence from other trials that local therapies might further extend survival for these patients with limited metastases.”