Importance: Consolidative durvalumab after definitive chemoradiation for unresectable locally advanced non-small cell lung cancer (NSCLC) can significantly improve progression-free survival (PFS) and overall survival (OS), as shown in the PACIFIC trial. However, whether patients with driver variations derive equal benefit from this regimen remains unclear.
Objectives: To compare outcomes of patients with locally advanced NSCLC with and without driver variations treated with the PACIFIC regimen.
Design, setting, and participants: This cohort study examined 104 patients with unresectable locally advanced NSCLC with mutational profiling treated at a tertiary cancer center with definitive chemoradiation and consolidative durvalumab from June 2017 through May 2020. Patients with recurrent disease or those receiving postoperative therapy were excluded. Outcomes were analyzed with Kaplan-Meier and multivariate regression analyses.
Exposures: Patients were grouped according to the presence of non-KRAS driver variations (EGFR exon 19 deletion, EGFR exon 20 insertion, EGFR exon 21 mutation [L858R], ERBB2 exon 20 insertion, EML4-ALK fusion, MET exon 14 skipping, NTRK2 fusion), KRAS driver variations, or no driver variations.
Main outcomes and measures: The primary outcomes were PFS, OS, and second progression-free survival (PFS2) times.
Results: The 104 patients had a median (IQR) age of 65.1 (9.8) years, with 55 females (53%) and 85 former or current smokers (88%). There were 43 patients (41%) with driver variations with a median PFS time of 8.4 months vs 40.1 months for patients without driver variations (hazard ratio [HR], 2.75; 95% CI, 1.64-4.62; log-rank P < .001). Both patients with non-KRAS and KRAS driver variations had worse PFS. No difference in OS was found between patients with and without driver variations (log rank P = .24). Among the 63 patients who developed progressive disease, those with non-KRAS driver variations had a median PFS2 time of 13.7 months vs 4.4 months for all other patients (HR, 0.37; 95% CI, 0.21-0.64; log-rank P = .001). Rates of overall grade 2 toxic effects or higher did not differ by driver mutation status.
Conclusions and relevance: In this cohort study, driver variations in patients with unresectable locally advanced NSCLC were associated with significantly shorter PFS time after definitive chemoradiation and consolidative durvalumab. These findings suggest the need to consider additional or alternative treatment options to the PACIFIC regimen for patients with driver variations.