…HER2-positive GC/GEJ pts who had progressed on trastuzumab….Pts received a median of 2 MCLA-128 cycles...1 pt had a confirmed CR (8+ cy), 9 pts had SD (sustained: 4, 5, 6, 12, 17 cy). CBR was 24% (6/25 pts)….MCLA-128 is very well tolerated with mainly grade 1/2 AEs. Promising single agent antitumor activity was seen in heavily pretreated GC/GEJ pts progressing on anti-HER2 therapy.