 This is a phase 2, randomized, double blind, placebo controlled, multi-center study to estimate the improvement in progression free survival compared to control subjects and evaluate the safety and tolerability of AMG 386 in combination with Cisplatin Capecitabine in the treatment of subjects with Metastatic Gastric, Gastroesophageal Junction, or Distal Esophageal Adenocarcinoma. AMG 386 is a man-made medication that is designed to stop the development of blood vessels in cancer tissues. Cancer tissues rely on the development of new blood vessels, a process called angiogenesis, to obtain a supply of oxygen and nutrients to grow. 