Evaluation of Efficacy, Safety of Vandetanib in Patients With Differentiated Thyroid Cancer

Participants who received vandetanib as randomized treatment were allowed, upon re-consent, to continue on open-label vandetanib if in the opinion of the Investigator the participant received benefit. Placebo participants who experienced disease progression within 60 days of unblinding were offered the option of treatment with open-label vandetanib if, in the Investigator's opinion, such treatment was of clinical benefit to the participant. Approximately 2 years; duration depends on individual participant response.