Safety Study of Enoblituzumab (MGA271) in Combination With Pembrolizumab or MGA012 in Refractory Cancer

The purpose of this study is to evaluate the safety of enoblituzumab (MGA271) in combination with Keytruda (pembrolizumab) when given to patients with B7-H3-expressing melanoma, squamous cell carcinoma of the head and neck (SCCHN), non small cell lung cancer (NSCLC), Urothelial Cancer and other B7-H3 expressing cancers. The study will also evaluate what is the highest dose of enoblituzumab that can be given safely when given with pembrolizumab. Assessments will also be done to see how the drug acts in the body (pharmacokinetics (PK), pharmacodynamics) and to evaluate potential anti-tumor activity of MGA271 in combination with pembrolizumab. Safety and efficacy of enoblituzumab in combination with MGA012 (anti-PD-1 monoclonal antibody; also known as INCMGA00012) will also be evaluated.