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.
Over the past decade, lung cancer treatment has undergone a major paradigm shift. A greater understanding of lung cancer biology has led to the development of many effective targeted therapies as well as of immunotherapy. Immune checkpoint inhibitors (ICIs) have shown tremendous benefit in the treatment of non-small cell lung cancer (NSCLC) and are now being used as first-line therapies in metastatic disease, consolidation therapy following chemoradiation in unresectable locally advanced disease, and adjuvant therapy following surgical resection and chemotherapy in resectable disease. Despite these benefits, predicting who will respond to ICIs has proven to be difficult and there remains a need to discover new predictive immunotherapy biomarkers. Furthermore, resistance to ICIs in lung cancer is frequent either because of a lack of response or disease progression after an initial response. The utility of ICIs in the treatment of small cell lung cancer (SCLC) remains limited to first-line treatment of extensive stage disease in combination with chemotherapy with modest impact on overall survival. It is thus important to explore and exploit additional targets to reap the full benefits of immunotherapy in the treatment of lung cancer. Here, we will summarize the current state of immunotherapy in lung cancer, discuss novel targets, and explore the intersection between DNA repair defects and immunotherapy.
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