24-Month Overall Survival from KEYNOTE-021 Cohort G: Pemetrexed and Carboplatin with or without Pembrolizumab as First-Line Therapy for Advanced Nonsquamous Non-Small Cell Lung Cancer

J Thorac Oncol. 2019 Jan;14(1):124-129. doi: 10.1016/j.jtho.2018.08.004. Epub 2018 Aug 21.


Introduction: Cohort G of KEYNOTE-021 (NCT02039674) evaluated the efficacy and safety of pembrolizumab plus pemetrexed-carboplatin (PC) versus PC alone as first-line therapy for advanced nonsquamous NSCLC. At the primary analysis (median follow-up time 10.6 months), pembrolizumab significantly improved objective response rate (ORR) and progression-free survival (PFS); the hazard ratio (HR) for overall survival (OS) was 0.90 (95% confidence interval [CI]: 0.42‒1.91). Herein, we present an updated analysis.

Methods: A total of 123 patients with previously untreated stage IIIB/IV nonsquamous NSCLC without EGFR and/or ALK receptor tyrosine kinase gene (ALK) aberrations were randomized 1:1 to four cycles of PC with or without pembrolizumab, 200 mg every 3 weeks. Pembrolizumab treatment continued for 2 years; maintenance pemetrexed was permitted in both groups. Eligible patients in the PC-alone group with radiologic progression could cross over to pembrolizumab monotherapy. p Values are nominal (one-sided p < 0.025).

Results: As of December 1, 2017, the median follow-up time was 23.9 months. The ORR was 56.7% with pembrolizumab plus PC versus 30.2% with PC alone (estimated difference 26.4% [95% CI: 8.9%‒42.4%, p = 0.0016]). PFS was significantly improved with pembrolizumab plus PC versus PC alone (HR = 0.53, 95% CI: 0.33‒0.86, p = 0.0049). A total of 41 patients in the PC-alone group received subsequent anti‒programmed death 1/anti‒programmed death ligand 1 therapy. The HR for OS was 0.56 (95% CI: 0.32‒0.95, p = 0.0151). Forty-one percent of patients in the pembrolizumab plus PC group and 27% in the PC-alone group had grade 3 to 5 treatment-related adverse events.

Conclusions: The significant improvements in PFS and ORR with pembrolizumab plus PC versus PC alone observed in the primary analysis were maintained, and the HR for OS with a 24-month median follow-up was 0.56, favoring pembrolizumab plus PC.

Keywords: Chemotherapy; Combination therapy; Nonsquamous non‒small cell lung cancer; Pembrolizumab.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal, Humanized / adverse effects*
  • Antibodies, Monoclonal, Humanized / pharmacology
  • Antibodies, Monoclonal, Humanized / therapeutic use*
  • Antineoplastic Combined Chemotherapy Protocols / adverse effects*
  • Antineoplastic Combined Chemotherapy Protocols / pharmacology
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • Carboplatin / adverse effects*
  • Carboplatin / pharmacology
  • Carboplatin / therapeutic use*
  • Carcinoma, Non-Small-Cell Lung / drug therapy*
  • Carcinoma, Non-Small-Cell Lung / mortality
  • Carcinoma, Non-Small-Cell Lung / pathology
  • Female
  • Humans
  • Lung Neoplasms / drug therapy*
  • Lung Neoplasms / mortality
  • Lung Neoplasms / pathology
  • Male
  • Pemetrexed / adverse effects*
  • Pemetrexed / pharmacology
  • Pemetrexed / therapeutic use*
  • Progression-Free Survival
  • Survival Rate
  • Time Factors


  • Antibodies, Monoclonal, Humanized
  • Pemetrexed
  • Carboplatin
  • pembrolizumab

Associated data

  • ClinicalTrials.gov/NCT02039674