This is a randomized, open Label, Phase 2 Study of MM-111 and Paclitaxel withTrastuzumab in Patients with HER2 Positive Carcinomas of the Distal Esophagus, Gastroesophageal (GE) Junction and Stomach Who Have Failed Front Line Metastatic or Locally Advanced Therapy. Approximately 120 patients will be randomized in a 1:1 ratio between the experimental and comparator arms.