Gastric and gastroesophageal junction (GEJ) adenocarcinoma is characterized by poor prognosis. Japan has the highest incidence of gastric and GEJ adenocarcinoma among the markets under study, making that country a commercially attractive and lucrative market for gastric cancer treatment. The disease’s rapid progression, most patients’ poor performance status, and the large number of elderly patients result in lower treatment rates than those of other cancer indications. Therapeutic options for gastric and GEJ adenocarcinoma are limited. Thus, opportunity in this market is largely untapped; in the HER2-positive patient segment an agent able to demonstrate statistically significant efficacy compared with that of the standard of care, Herceptin (Roche/Genentech/Chugai’s trastuzumab), is likely to gain regulatory approval and enjoy strong uptake. The 2014 approval of the angiogenesis inhibitor, Cyramza (Eli Lilly’s ramucirumab), is forecast to partially fulfill the need for effective and targeted second-line treatment, particularly for patients who are HER2-negative. The gastric and GEJ adenocarcinoma late-stage pipeline is buoyant; the eagerly anticipated emergence of multiple therapies belonging to a wide variety of drug classes is expected to diversify treatment options in all population segments during our forecast period.