Four patients had a screening CAPRIN-1 score of 3+, and all achieved partial response….TRK-950 binds to a newly described target, CAPRIN-1, and has an acceptable safety and tolerability profile when combined with ramucirumab and paclitaxel in gastric cancer including GEJ cancer. Preliminary clinical activity is demonstrated in pre-treated patients with encouraging response rates, particularly enriched by the expression of CAPRIN-1.