A PHASE 3, RANDOMIZED, DOUBLE-BLINDED STUDY OF IMC-1121B AND BEST SUPPORTIVE CARE (BSC) VERSUS PLACEBO AND BSC IN THE TREATMENT OF METASTATIC GASTRIC OR GASTROESOPHAGEAL JUNCTION ADENOCARCINOMA FOLLOWING DISEASE PROGRESSION ON FIRST-LINE PLATINUM- OR FLUOROPYRIMIDINE-CONTAINING COMBINATION THERAPY

INTERVENTION: Patients will be randomized on a 2:1 basis to IMC‐1121B por placebo, respectively. Patients in the active‐treatment group will receive IMC‐1121B, administered via intravenous (I.V.) infusion every 2 weeks at a dose of 8 mg/kg, and BSC as determined appropriate by the investigator (s). Patients in the placebo group will receive an equivalent volume of placebo by I.V. infusion every 2 weeks, and BSC as determined appropriate by the investigator (s). CONDITION: PRIMARY OUTCOME: Patients will be evaluated for response according to RECIST. Pacientes will be re‐evaluated for response every 6 weeks in addition to baseline scan, confirmatory scans should also be obtained no fewer tan 4 weeks. In addition to a baseline scan, confirmatory scans should also be obtained no fewer tan 4 weeks following initial documentation of objetive response.; NAME OF THE RESULT: The baseline tumor burden (unidimensionally‐measurable and nonmeasurable disease) will be assessed as closely as posible to the beginning of treatment and never more tan 21 days prior to the first treatment sesión (14 days prior to randomization). The investigator will prospectively identify the lesions to be follwed to to evaluate the patient’s response to therapy.; USED MEASURING METHOD :The same method of assessment and the same technique should be used to characterize each identified and reported lesión at baseline and at reassessment during treatment. Imaging‐based evaluation will be preferred to evaluation by clinical examination when both methods have been used to assess the antitumor effect of a treatment. Lesions evaluated clinically will only be considered measurable when they are superficial (eg, skin nodules palpable lymph nodes). In the case of skin lesions, docuemntation by color photography, including a ruler to estimate the size of the lesión, is recommended. CT and MRI will be considered the best currentely available and reproducible methods to measure target lesions.; PERIOD OF TIME WHERE THE MEASUREMENT WILL BE CONDUCTED AND WHICH WILL ALLOW OBTAINING THE PRIMARY RESULT: A treatment cycle will be defined as 2 weeks, wirh radiologic evaluation every 6 weeks. There will be no interrupcion between treatment cycles. Patients will be treated until there is evidence of PD, toxicity requiring cessation, withdrawal of consent, or until other withdrawal criteria are met. SECONDARY OUTCOME: N.A ; NAME OF THE RESULT: N.A ; USED MEASURING METHOD :N.A ; PERIOD OF TIME WHERE THE MEASUREMENT WILL BE CONDUCTED AND WHICH WILL ALLOW OBTAINING THE SECONDARY RESULT: N.A INCLUSION CRITERIA: 1. The patient has histologically‐or cytologically‐ confirmed gastric carcinoma, including gastric adenocarcinoma or GEJ adenocarcinoma (patients with adenocarcinoma of the distal esophagus are eligible if the primary tumor involves the GEJ). 2. The patient has metastatic disease or locally recurrent, unresectable disease. • Patients with nonregional lymph node metastases are eligible; lumph node metastases must be measurable as defined by the Response Evaluation Criteria in Solid Tumors (RECIST), Version 1.0.[56]. • Patients with locally‐recurrent, unresectable disease are eligible. • For patients who have received prior radiation therapy, measurable or evaluable lesions must be outside the radiation field, or (for lesions within the radiation field) there must be documented progression following radiation therapy. 3. The patient has measurable disease and/or evaluable disease. Measurable disease is defined as at least o