Real-world treatment patterns and outcomes in advanced/metastatic gastric cancer or gastroesophageal junction adenocarcinoma treated with first-line anti-HER2 therapy in England

Background: This study aimed to examine real-world treatment patterns and outcomes in patients with human epidermal growth factor receptor 2 (HER2)-positive gastric cancer (GC) or gastroesophageal junction (GEJ) adenocarcinoma receiving anticancer therapy in England.Methods: Using the Cancer Analysis System English Cancer Outcomes Services Dataset, we retrospectively analyzed real-world (rw) treatment patterns, overall survival (rwOS), time to treatment discontinuation/death (rwTTD), and time to next treatment/death (rwTTNTD) in adults with inoperable, locally advanced or metastatic GC/GEJ adenocarcinoma on trastuzumab-based first line of treatment (1LoT) between January 2015 and December 2019.Results: Among 948 patients included (median age 67.0 years), most were male (82.1%), with GEJ adenocarcinoma (57.4%) and de novo disease (81.8%); 33.3% patients received 2LoT and 6.6% received 3LoT.The most common regimen was capecitabine + cisplatin + trastuzumab in 1LoT (54.9%), paclitaxel in 2LoT (36.4%), and fluorouracil + irinotecan in 3LoT (19.1%).Median (Q1-Q3) rwOS and rwTTD for 1LoT were 11.8 months (6.2-21.5 months) and 6.3 months (3.0-10.6 months), respectively; these reduced to 6.1 months (3.4-11.2months) and 2.8 months (1.7-4.6 months) for 2LoT, and 5.9 months (3.2-9.5 months) and 2.3 months (1.5-4.6 months) for 3LoT.Median rwTTNTD was 9.0 months (5.1-15.0months), 5.5 months (3.0-8.5 months), and 5.7 months (3.0-9.2 months) for 1LoT, 2LoT, and 3LoT, respectively.Conclusions: Poor outcomes persist for HER2-positive GC/GEJ adenocarcinoma progressing after 1LoT.More effective treatments, ideally ones targeting HER2, are needed.