A phase 2 trial of consolidation pembrolizumab following concurrent chemoradiation for patients with unresectable stage III non-small cell lung cancer: Hoosier Cancer Research Network LUN 14-179

Background: Five-year overall survival (OS) for patients with unresectable stage III non-small cell lung cancer (NSCLC) is poor. Until recently, a standard of care was concurrent chemoradiation alone. Patients with metastatic NSCLC treated with anti-programmed death 1 antibodies have demonstrated improved OS. This trial evaluated pembrolizumab as consolidation therapy after concurrent chemoradiation in patients with unresectable stage III disease.

Methods: Patients with unresectable stage III NSCLC received concurrent chemoradiation with cisplatin and etoposide, cisplatin and pemetrexed, or carboplatin and paclitaxel and 59.4 to 66.6 Gy of radiation. Patients with nonprogression of disease were enrolled and received pembrolizumab (200 mg intravenously every 3 weeks for up to 12 months). The primary endpoint was the time to metastatic disease or death (TMDD). Secondary endpoints included progression-free survival (PFS) and OS.

Results: The median follow-up for 93 patients (92 for efficacy) was 32.2 months (range, 1.2-46.6 months). The median TMDD was 30.7 months (95% confidence interval [CI], 18.7 months to not reached), which was significantly longer than the historical control of 12 months (P < .0001). The median PFS was 18.7 months (95% CI, 12.4-33.8 months), and the median OS was 35.8 months (95% CI, 24.2 months to not reached). The 1-, 2-, and 3-year OS estimates were 81.2%, 62.0%, and 48.5%, respectively. Forty patients (43.5%) completed 12 months of treatment (median number of cycles, 13.5). Symptomatic pneumonitis (grade 2 or higher) was noted in 16 patients (17.2%); these cases included 4 grade 3 events (4.3%), 1 grade 4 event (1.1%), and 1 grade 5 event (1.1%).

Conclusions: Consolidation pembrolizumab after concurrent chemoradiation improves TMDD, PFS, and OS in comparison with historical controls of chemoradiation alone. Rates of grade 3 to 5 pneumonitis were similar to those reported with chemoradiation alone.