Treatment patterns and outcomes in Chinese gastric cancer by HER2 status: A non-interventional registry study (EVIDENCE).

4025 Background: Gastric cancer (GC) is the second leading cause of cancer-related deaths in China. Trastuzumab (TRA) has been used to treat HER2+ metastatic gastric cancer (mGC) in China since 2012. However, real-world data on effectiveness and safety in Chinese patients are limited. Methods: This prospective, multicenter (85 hospitals), real-world noninterventional registry study evaluated the effectiveness and safety of TRA in five cohorts of Chinese GC patients with different HER2 statuses from April 2013 to June 2018. Effectiveness analysis was conducted in three cohorts: Cohort I (HER2+ mGC with TRA), Cohort II (HER2+ mGC untreated with TRA) and Cohort IV (HER2− mGC untreated with TRA). Safety outcomes of TRA-related adverse events (AEs) were analyzed in Cohort I. Results: Cohorts I, II and IV included 709 patients (174, 113 and 422, respectively; mean age 57.8 years; 72% male); 64.9% of patients were ECOG 0–1, 93.7% had a primary GC tumor and 42.3% were at stage T4. Progressive disease was the cause of death in 32.8%, 27.4% and 29.9% in Cohorts I, II and IV, respectively. Respective mean duration of follow-up was 422.5, 287.5 and 277.5 days. Median overall survival (OS) was 22.3, 17.2 and 17.4 months, respectively. After excluding patients who had surgery, the respective median OS was 19.9, 15.3, and 12.6 months. For the first-line treatment, the median OS in Cohort I was 22.1 months, and the median progression free survival (PFS) was 8.2, 6.9 and 6.2 months in Cohorts I, II and IV, respectively. Response rates (RR) for first-line treatment in Cohorts I, II and IV were 51.7%, 18.4% and 32.8%, respectively. After propensity score matching, OS, PFS and RR were all significantly better in Cohort I versus II (all P<0.05). The most common regimen, TRA+XELOX (capecitabine+oxaliplatin), was estimated to have the longest median OS at 34.6 months. Grade ≥3 AEs were reported in 33.9% (59/174) of patients in Cohort I; anemia was the most common AE (12.1%). Conclusions: TRA improved OS and PFS in Chinese HER2+ mGC patients compared with chemotherapy alone and was well tolerated and effective when combined with a range of other therapies in a real-world setting. Clinical trial information: NCT01839500.