Pembrolizumab in Treating Patients With Advanced Uveal Melanoma

PRIMARY OBJECTIVES: I. To evaluate objective response rate (ORR) in patients with advanced uveal melanoma receiving pembrolizumab. SECONDARY OBJECTIVES: I. To evaluate progression-free survival (PFS) in patients with advanced uveal melanoma receiving pembrolizumab. II. To evaluate safety, tolerability and adverse experience profile of pembrolizumab in uveal melanoma. III. To evaluate overall survival (OS) in patients with advanced uveal melanoma receiving pembrolizumab. TERTIARY OBJECTIVES: I. To evaluate objective response rate (ORR; complete response + partial response) in patients with advanced uveal melanoma receiving pembrolizumab as stratified by programmed cell death-ligand 1 (PD-L1) expression and guanine nucleotide-binding protein (GNA)Q/GNA11 mutation status. II. To evaluate ORR in patients previously treated with ipilimumab or with mitogen-activated protein kinase kinase (MEK) inhibitors. OUTLINE: Patients receive pembrolizumab intravenously (IV) over 30 minutes on day 1. Treatment repeats every 3 weeks for 24 months in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up at 30 days and then every 12 weeks.