- Known history of or clinical evidence of central nervous system (CNS) metastases or leptomeningeal carcinomatosis except for individuals who have previously treated CNS metastases, are asymptomatic, and have had no requirement for steroids or antiseizure medication for ≥ 3 months prior to study enrollment. Routine screening with CNS imaging studies (computed tomography [CT] or magnetic resonance imaging [MRI]) is required only if clinically indicated or if the subject has a history of CNS metastases;