Inclusion Criteria:  Signed informed consent must be obtained prior to performing any specific pre-screening and screening procedure Male or female >= 18 years of age at the time of informed consent Histologically or cytologically confirmed diagnosis of advanced/metastatic differentiated thyroid cancer Radio active iodine refractory disease BRAFV600E mutation positive tumor sample as per Novartis designated central laboratory result Has progressed on at least 1 but not more than 2 prior VEGFR targeted therapy Eastern Cooperative Oncology Group performance status >= 2 At least one measurable lesion as defined by RECIST 1.1  Exclusion Criteria:  Anaplastic or medullary carcinoma of the Tyroid Previous treatment with BRAF inhibitor and/or MEK inhibitor Concomitant RET Fusion Positive Thyroid cancer Receipt of any type of small molecule kinase inhibitor within 2 weeks before randomization Receipt of any type of cancer antibody or systemic chemotherapy within 4 weeks before randomization Receipt of radiation therapy for bone metastasis within 2 weeks or any other radiation therapy within 4 weeks before randomization A history or current evidence/risk of retinal vein occlusion or central serous retinopathy