Primary Objective The primary objective is to determine the overall response rate after treatment with abemaciclib in patients with anaplastic thyroid/undifferentiated thyroid cancer.~Secondary Objectives The secondary objectives are to describe the overall survival (OS) and progression-free survival (PFS) after treatment with abemaciclib in patients with anaplastic thyroid/undifferentiated thyroid cancer.Safety assessments of AE's will also be analysed
The purpose of the study is to evaluate the efficacy of treatment with abemaciclib in patients with anaplastic thyroid/undifferentiated thyroid