How do you consider first and subsequent lines of treatment sequencing in metastatic gastric/GEJ cancer that is both HER2+ and CPS>5?  

I consider the current standard-of-care in the 1L setting to be pembrolizumab + trastuzumab/chemotherapy irrespective of PD-L1 status. In the published data for the KEYNOTE-811 study, which only includes the initial 264 patients in a planned interim analysis, about 85% of tumors were PD-L1 CPS ...

Correlation between high CPS and better response to PD-1 inhibitors is reported in multiple studies in gastroesophageal cancer. However, the majority of patients with HER2 positive disease were included in KEYNOTE-811, and the response rates between positive PD-L1(CPS>=1) vs negative did not have...

This is a situation in which we, fortunately, have several options. Assuming no major comorbidities (cardiac or autoimmune), first-line therapy would generally consist of chemo + trastuzumab + pembrolizumab (based on results from the Merck 811 study showing greater response rates with this combinati...