Efficacy and Safety of Vandetanib (ZD6474) in Patients With Metastatic Papillary or Follicular Thyroid Cancer

This was a parallel group, randomized, double blind, placebo controlled, multicentre study designed to assess whether vandetanib (ZD6474) conferred an improvement in PFS as compared to placebo in participants with locally advanced or metastatic papillary or follicular thyroid carcinoma failing or unsuitable for radioiodine therapy. The trial was of a sufficient size so that if vandetanib (ZD6474) was truly active there was a high probability that it would demonstrate an effect sufficiently promising to warrant a follow-up assessment. * Participants were seen weekly for the first 2 weeks, then again at Week 4, Week 8, and Week 12 after randomization, and every 12 weeks thereafter. Upon disease progression, all participants (both active and placebo) were unblinded and given the option to discontinue blinded study treatment and enter follow up and survival, or begin open label vandetanib (ZD6474) 300 mg treatment. All participants were followed to collect survival data until greater than or equal to (>=) 50% of participants had died. Participants who were taking vandetanib (ZD6474) at the time of study closure and wished to remain on therapy were allowed to continue for as long as the Investigator felt that they were obtaining clinical benefit, or until they were given another anti-cancer therapy. The safety data from all participants was assessed on an ongoing basis, including discontinuation and follow up. * Radiologic evaluation using RECIST criteria was performed every 12 weeks (+/- 2 weeks). All medical images were centralized assessed at the site and centrally reviewed. Participants were evaluated until progression, and then followed up for survival, regardless of whether they continued randomized treatment, unless they withdrew consent. Post progression open-label vandetanib (ZD6474) were offered at the investigators discretion. * All participants submitted a suitable archived tumor sample prior to randomization. In the event that a suitable archived sample was not available within 2 weeks prior to randomization, a fresh tumor sample was obtained in its place prior to randomization. If a participant underwent the fresh tumor biopsy procedure, this specimen would satisfy the first optional tumor biopsy submission should they consented to the exploratory part of the study.