Evaluating the Safety and Efficacy of Oral Lenvatinib in Medullary and Iodine-131 Refractory, Unresectable Differentiated Thyroid Cancers, Stratified by Histology

This study contained 3 Phases: the Pretreatment Phase, the Treatment Phase, and the Extension Phase. The Pretreatment Phase lasted no longer than 28 days. Informed consent was obtained and protocol eligibility and disease characteristics were established prior to treatment. The Treatment Phase consisted of a Treatment Period and a Follow-up Period. The Treatment Period of the Treatment Phase began at the time that the first participant began study drug administration and ended at the time when all participants enrolled completed 8 cycles of treatment or discontinued study treatment prior to the eighth cycle (ie, time of data cutoff for the primary study analysis \[Primary Completion Date\]). All participants then entered the Extension Phase. The Extension Phase consisted of a Treatment Period and a Follow-up Period. The Extension Phase began immediately after the Treatment Phase ended and included all participants that were either still receiving treatment or in follow-up. The time of data cutoff for the primary study analysis occurred when all subjects in the study completed 8 cycles of treatment or discontinued study treatment prior to the eighth cycle.