Treatment of Stage IV Non-Small Cell Lung Cancer with Pembrolizumab in Combination with Platinum-Based Doublet Chemotherapy in Vietnam.

Introduction: Lung cancer has been one of the most prevalent cancers worldwide in recent decades. According to the findings of the KEYNOTE-407 (2018) study on patients with stage IV squamous cell lung cancer, the combination of pembrolizumab and chemotherapy in the first-line treatment prolongs overall survival compared with chemotherapy alone. This study aimed to evaluate the efficacy and side effects of treating patients with stage IV non-small cell lung cancer with pembrolizumab in combination with platinum-based doublet chemotherapy.

Methods: A retrospective multicenter study on 46 patients at four hospitals in Vietnam between June 2018 and August 2022. Patients received first-line treatment with a protocol of pembrolizumab in combination with platinum-based doublet chemotherapy (pemetrexed plus carboplatin or paclitaxel plus carboplatin). The study's primary endpoints were progression-free survival and safety. The secondary endpoint was overall survival.

Results: The median progression-free survival was 11.0 months (95% CI, 7.4-14.7 months). The median overall survival was 23.1 months (95% CI, 18.4-27.8 months). The survival rate of patients after 1 and 2 years was 82.3% and 43.3%, respectively. The most common side effects were anemia and elevated liver enzymes, but they were primarily mild or moderate severity. Progression-free survival did not depend on cancer type based on histology (p = 0.13). The progression-free survival was independent of programmed death ligand-1 expression levels < 50% or ≥ 50% (p = 0.68).

Conclusion: Treatment of stage IV non-small cell lung cancer without EGFR and ALK gene mutations with the immunotherapy protocol of pembrolizumab in combination with platinum-based doublet chemotherapy resulted in favorable outcomes without any new safety concerns. A larger sample size and longer follow-up in the future are necessary to yield more complete results.