STUDY OF EFFICACY AND SAFETY OF PDR001 IN PATIENTS WITH ADVANCED OR METASTATIC, WELL-DIFFERENTIATED, NON-FUNCTIONAL NEUROENDOCRINE TUMORS OF PANCREATIC, GASTROINTESTINAL (GI), OR THORACIC ORIGIN OR POORLY-DIFFERENTIATED GASTROENTEROPANCREATIC NEUROENDOCRINE CARCINOMA (GEP-NEC):