Efficacy and Safety Study of GSK1120212, a MEK Inhibitor, in Subjects With Uveal Melanoma

Inclusion Criteria: * Histologically or cytologically confirmed diagnosis of metastatic uveal melanoma or previously documented mutation-positive GNAQ or GNA11 metastatic melanoma not previously treated with a MEK inhibitor. * Provide archival tumor tissue or, if tissue blocks are not available, undergo fresh tumor biopsy prior to enrollment. * The patient has a radiographically measurable tumor. * ECOG performance status 0, 1, or 2. * The patient is able to swallow and retain oral medication. * Life expectancy of at least 4 months. * Toxicities from previous anti-cancer therapy (except alopecia) are recovered (Grade 1 or less) at the time of enrollment. * The patient has adequate organ and bone marrow function. * Sexually active patients must use medically acceptable methods of contraception during the course of the study. * Female patients of childbearing potential must have a negative serum pregnancy test at screening. Exclusion Criteria: * The patient has had any of the following within 21 days of starting study drug or anticipates the need for any of the following during the course of study treatment: chemotherapy, immunotherapy, biologic therapy, hormone therapy, major surgery, or tumor embolization. * The patient has received experimental therapy within 21 days of starting study drug. * The patient has received nitrosourea or mitomycin C within 42 days of starting study drug. * The patient has received any herbal medications or palliative radiotherapy within 14 days of starting study drug. * The patient is currently receiving anticoagulation therapy that is not well controlled. * Ongoing or newly diagnosed eye abnormality other than symptoms due to uveal melanoma. * History of retinal vein occlusion or central serous retinopathy. * Current severe, uncontrolled systemic disease. * History of leptomeningeal disease or spinal cord compression secondary to metastasis. * Brain metastasis, unless previously treated with surgery, whole-brain radiation or stereotactic radiosurgery and the disease has been stable for at least 3 months without steroid use or on a stable dose of steroids for at least 1 month prior to starting study drug. Stability of brain metastases must be confirmed with imaging. * The patient has a concurrent, active hematological malignancy or other solid tumor malignancy. * History of clinically significant cardiac or pulmonary dysfunction. * Allergy or hypersensitivity to components of the GSK1120212 formulation. * The patient is pregnant or breastfeeding.