CD8+ T Cell Therapy and Pembrolizumab in Treating Patients With Metastatic Gastrointestinal Tumors

PRIMARY OBJECTIVES: I. Assess the safety of using a personalized adoptive T cell therapy in patients with advanced gastrointestinal malignancies. SECONDARY OBJECTIVES: I. Assess the persistence of an immune response after T cell infusion. II. Determine the clinical benefit of adoptive T cell therapy in advanced gastrointestinal cancers. OUTLINE: Beginning 2 days prior to CD8+ T cell infusion, patients receive cyclophosphamide intravenously (IV) over 30 minutes. Patients undergo CD8+ T cell infusion IV over 2 hours on day 0 and receive aldesleukin subcutaneously (SC) twice daily (BID) on days 1-14. Beginning on day 1 about 24 hours after CD8+ T cell infusion, patients receive pembrolizumab IV over 30-60 minutes on weeks 3, 6, 12, and 15. After completion of study treatment, patients are followed up for 24 weeks.