Abstract
The CheckMate 649 trial demonstrated the clinical benefit of nivolumab plus chemotherapy in patients with human epidermal growth factor receptor 2 (HER2)-negative advanced gastric cancer. However, the background discrepancy between clinical practice and randomized controlled trials may impact the therapeutic strategy and prognosis of patients. This study aimed to assess the clinical significance of eligibility criteria determined by the CheckMate 649 trial and identify prognostic factors in clinical practice. A total of 160 patients with HER2-negative metastatic gastric cancer who underwent chemotherapy were retrospectively enrolled and classified into two groups based on eligibility criteria. Among the 160 patients, 76 (47.5%) and 84 (52.5%) were included in the eligible and ineligible groups, respectively. The ineligible group had a significantly lower induction of second- and third-line chemotherapy than the eligible group (P = 0.02 and P = 0.02, respectively). The median overall survival in the eligible and ineligible groups was 22.9 and 10.5 months, respectively, with the ineligible group having a significantly poorer prognosis than the eligible group (P < 0.01). Responders to first-line chemotherapy had a better prognosis than non-responders in both groups (P = 0.01 and P < 0.01, respectively). Multivariate analyses identified disease control as an independent prognostic factor in both groups (P < 0.01 and P < 0.01, respectively). Patients with a poor general condition who fulfilled the ineligibility criteria as determined using randomized controlled trials are included in clinical practice, and these criteria are related to tumor response and prognosis.