Background: Although several randomized trials (RCTs) showed survival benefits of immune checkpoint inhibitor (ICI) plus first-line chemotherapy for advanced gastric or gastroesophageal cancer (AGC), these trials could enroll patients who fulfilled the strict eligibility criteria or waited for certain screening period for central assessment of PD-L1 status.
Methods: We retrospectively compared characteristics and clinical outcomes of the patients with AGC who received first-line chemotherapy in control arm of RCTs with ICIs (control group) or clinical practice (practice group) at our institution from February 2016 to April 2019.
Results: The control group had a better baseline Eastern Cooperative Oncology Group performance status (PS0, 81.2% vs. 51.4%, p < 0.001) and a longer interval from first visit to first-line chemotherapy initiation (19 days vs. 9 days, p < 0.001) than the practice group. Median overall survival (OS) was 20.3 months in control group and 15.7 months in practice group, with a trend of longer OS in control group than that in practice group (hazard ratio, 0.71; p = 0.062). More patients in control group were treated with subsequent chemotherapy including ICIs.
Conclusion: Patients with AGC in RCTs of ICIs had a better PS or a higher chance to receive subsequent chemotherapy, resulting in a better prognosis than those treated in clinical practice. This information should be considered when interpreting RCT results and applying new treatments into clinical practice.
Keywords: CheckMate 649; Clinical trial; Gastric cancer; Immune checkpoint inhibitor; Nivolumab.
© 2022. The Author(s) under exclusive licence to Japan Society of Clinical Oncology.