- Patients must be free of brain metastasis by contrast-enhanced computed tomography (CT)/magnetic resonance imaging (MRI) scans within 4 weeks prior to enrollment; if known to have prior brain metastases, must not have evidence of active brain disease after definitive therapy (surgery, radiation therapy or stereotactic radiosurgery) on two successive MRI evaluations at least 3 months apart (one of which is =< 4 weeks prior to starting the study drugs)