Inclusion Criteria:

- Provision of informed consent to participate in the study as well as provision of
informed consent to provide a sample of a previously obtained archival tumour biopsy.

- Female or male aged 18 years and older with previously confirmed histological
diagnosis of locally advanced or metastatic poorly differentiated or papillary
thyroid cancer not amenable to surgical resection, external beam radiotherapy or
local therapy.

- Measurable disease defined as at least one lesion, not irradiated within 12 weeks of
the date of randomisation, that can be accurately measured at baseline.

- Patients must have progression and be RAI-refractory/resistant or unsuitable for RAI.

- TSH suppression below 0.5 mU/L is required.

Exclusion Criteria:

- Risk of prolonged QTc as defined by history of QT prolongation; current therapy with
any medication known to be associated with Torsades de Pointes or prolongation of QT;
congenital long QT syndrome.

- Previous therapy with approved or investigational tyrosine kinase or anti-VEGF
receptor inhibitors or targeted therapies (e.g. multi-targeted kinase inhibitors such
as sorafenib, AMG-706, sunitinib, pazopanib, lenvatinib).

- RAI therapy within 12 weeks prior to first dose of study drug, and radiation therapy
other than RAI, including external beam, if not completed prior to randomisation.

- Inadequate organ function as defined by elevated ALT, AST, ALP or bilirubin; or
creatinine clearance <50 ml/min.