P1.100. Impact of Immunotherapy Introduction on Real-World Treatment Patterns for Advanced Esophageal Cancer: A Retrospective Database Cohort Study From Japan

Topic Esophageal Cancer: Management of Metastatic Cancer Background Treatment of advanced esophageal cancer (EC) has evolved with immune checkpoint inhibitors (ICIs), including nivolumab or pembrolizumab plus doublet chemotherapy (IO-chemo) and nivolumab plus ipilimumab as first-line therapy, and nivolumab and pembrolizumab as second-line therapy. Here, we report a temporal shift in real-world treatment patterns for advanced EC in Japan. Methods This observational, retrospective cohort study using a hospital-based administrative claims database (Medical Data Vision Co., Ltd) included patients aged >18 years with EC who had stage IVB disease or metastasis and initiated EC practice guideline-listed 1L therapy from 2017 to 2024. Regimens in each line of therapy were defined as any combination of agents indicated for EC that was prescribed within 14 days of therapy initiation and considered ended when all agents in the regimen were not prescribed for >90 days or a different EC agent was started. Treatment patterns were assessed by year of 1L therapy initiation. Results Of 2,657 pts included, 85% were male and the median age at 1L initiation was 70 years (IQR: 64-75). For 1L therapy, chemotherapy was predominantly used in 2017-2021, while ICI-containing regimens (IO-chemo and nivolumab + ipilimumab) became most common in 2022-2024 (table). For 2L therapy, taxanes were most frequently used in patients initiating 1L therapy in 2017-2019, while nivolumab monotherapy became most common in those initiating 1L therapy in 2020-2021. Following the adoption of 1L ICI regimens in 2022, nivolumab use declined and taxane use increased. Increased use of ICI-containing regimens coincided with longer 1L and 2L treatment durations. Conclusion The introduction of ICIs in clinical practice in Japan has shifted treatment patterns for advanced EC, with a trend toward prolonged treatment durations for both 1L and 2L therapy. Detailed data in post-1L ICI era, including baseline characteristics and treatment durations by 1L regimen type (IO-chemo and nivolumab + ipilimumab), will be presented.