Inclusion Criteria:

- Adult patients. >/= 18 years of age

- Histologically confirmed metastatic or unresectable papillary thyroid cancer for
which standard curative or palliative measures do not exist or are no longer
effective; patients whose tumors exhibit areas of "other histology" may be enrolled,
provided the tumor histology remains predominantly papillary

- Positive for BRAF V600 mutation (Roche Cobas 4800 BRAF V600 Mutation Test)

- Radioactive Iodine resistant disease

- Prior therapy excluding (Cohort 1) or including (Cohort 2) tyrosine kinase inhibitor
(TKI)

- Clinically relevant disease progression according to RECIST criteria within the
prior 14 months

- Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1

- Adequate hematological, renal and liver function

Exclusion Criteria:

- Histological diagnosis other than papillary thyroid carcinoma (PTC), including
squamous cell variants of PTC or PTC with areas of squamous metaplasia

- Active or untreated CNS metastases

- History of or known carcinomatous meningitis

- Anticipated or ongoing administration of any anti-cancer therapies other than those
administered in the study

- Active squamous cell skin cancer that has not been excised or adequately healed post
excision

- Previous treatment with any agent that specifically and selectively targets the MEK
or BRAF pathway

- Prior radiotherapy to the only measurable lesion

- Clinically relevant cardio-vascular disease or event within the prior 6 months