Pembrolizumab plus chemotherapy versus chemotherapy for advanced esophageal cancer: 5-year extended follow-up for the randomized phase III KEYNOTE-590 study

Abstract

Background: The global KEYNOTE-590 trial was the first to show a significant improvement in survival with immunotherapy plus chemotherapy in the first-line treatment of esophageal cancer (EC) and supported the approval of pembrolizumab plus chemotherapy in this setting. After a median follow-up of 22.6 months, pembrolizumab plus chemotherapy compared with placebo plus chemotherapy had a manageable safety profile and significantly improved survival of participants with previously untreated advanced EC. Results of a median follow-up of 58.8 months (range 49.2-70.6 months) are reported. Patients and methods: Adults with previously untreated advanced EC or Siewert type 1 gastroesophageal junction cancer were randomly assigned 1 : 1 to receive chemotherapy with or without pembrolizumab. Study outcomes were efficacy and safety. Results: Overall, 749 participants received pembrolizumab plus chemotherapy (n = 373) or placebo plus chemotherapy (n = 376). Median overall survival was 12.3 months versus 9.8 months [hazard ratio (HR) 0.72, 95% confidence interval (CI) 0.62-0.84] with pembrolizumab plus chemotherapy versus placebo plus chemotherapy; 5-year survival rates were 10.6% and 3.0%. Median progression-free survival (PFS) was 6.3 months versus 5.8 months (HR 0.64, 95% CI 0.54-0.75); 5-year PFS rates were 5.5% and not reached. Grade >= 3 treatment-related adverse events occurred in 71.9% and 67.6% of participants in the pembrolizumab plus chemotherapy and placebo plus chemotherapy groups, respectively. Conclusion: Data from KEYNOTE-590 continue to show durable efficacy after 5 years, and pembrolizumab plus chemotherapy more than tripled the 5-year overall survival rate compared with placebo plus chemotherapy, with no new safety signals. These results support first-line therapy with pembrolizumab plus chemotherapy as standard for previously untreated patients with advanced EC with programmed death-ligand 1 combined positive score >= 1.