Real-world treatment patterns, testing patterns, and clinical outcomes of first-line (1L) therapy for metastatic gastric cancer, gastroesophageal junction cancer, or esophageal adenocarcinoma (mGC/GEJC/EAC).

Abstract

275 Background: GC/GEJC/EAC are among the leading causes of cancer-related morbidity and mortality worldwide. Nivolumab + fluoropyrimidine- + platinum-containing chemotherapy (NIVO+chemo) has demonstrated superior efficacy in patients with advanced non-HER2-positive (HER2-) GC/GEJC/EAC versus chemo alone in the CheckMate 649 trial. The objective of this study was to characterize real-world treatment and PD-L1 testing patterns in the 1L setting for mGC/GEJC/EAC since the FDA approval of NIVO+chemo on April 16, 2021. Methods: This retrospective observational study used the electronic medical record data from the ConcertAI Patient360 database. Adult patients with HER2- mGC/GEJC/EAC and 1L initiation date (index date) between April 16, 2021 and October 31, 2022 were included. PD-L1 testing patterns and 1L regimens were described overall and stratified by PD-L1 testing. The analyses of clinical outcomes are currently ongoing. Results: A total of 161 patients with mGC/GEJC/EAC met the inclusion criteria. The median age at index was 67.0 years, 76.4% were male, and the median follow-up time from index date was 6.7 months. 81 (50.3%) patients had evidence of receiving at least one PD-L1 test (median [interquartile range] time from first test to 1L initiation: 0.4 [-0.1, 1.0] months) among whom 28 (34.6%) had the first test documented after 1L initiation. Overall, 1L immunotherapy-based regimens were received by 63 (39.1%) patients, with NIVO+chemo being the most common (n = 47; 29.2%). 1L fluoropyrimidine- + platinum-containing chemotherapy and other chemotherapies were received by 51 (31.7%) and 42 (26.1%) patients, respectively. Among patients with evidence of PD-L1 testing, 31 (38.3%) received NIVO+chemo, and 37 (45.7%) received chemotherapy alone. Among those without evidence of PD-L1 testing, 56 (70.0%) received chemotherapy alone, and 16 (20.0%) received NIVO+chemo. Conclusions: These preliminary findings show an early uptake of NIVO+chemo in the advanced or metastatic GC/GEJC/EAC patient population. With a majority of PD-L1 untested patients receiving chemotherapy only as 1L therapy, there is an opportunity for these patients to potentially benefit from immuno-oncology containing regimens. Further analyses are needed to characterize the chemotherapy only treated patient population.