- Subjects with previously untreated brain metastases. Subjects with brain metastases that were previously treated with gamma knife or whole brain radiation may enroll two weeks or four weeks after treatment, respectively. These subjects must be asymptomatic and either off corticosteroids or on a stable dose of corticosteroids for at least one month prior to the first dose of GSK1120212. Subjects are not permitted to receive enzyme inducing anti-epileptic drugs (EIAEDs) during the study.