Vudalimab for the Treatment of Locally Advanced or Metastatic Anaplastic Thyroid Cancer or Hurthle Cell Thyroid Cancer

PRIMARY OBJECTIVE: I. To evaluate the antineoplastic efficacy of vudalimab (XmAb2071) in anaplastic thyroid cancer, as measured by the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. SECONDARY OBJECTIVES: I. To estimate progression-free survival (PFS) in patients with anaplastic thyroid cancer who have received XmAb20717 therapy. II. To estimate 16-week progression-free survival (PFS-16) in patients with anaplastic thyroid cancer who have received XmAb20717 therapy. III. To estimate overall survival (OS) in patients with anaplastic thyroid cancer who have received XmAb20717 therapy. IV. To determine the clinical benefit rate (CBR) in patients with anaplastic thyroid cancer who have received XmAb20717 therapy. V. To calculate the duration of response (DOR) in patients with anaplastic thyroid cancer who have responded to XmAb20717 therapy. VI. To calculate the duration of clinical benefit (DoCB) in patients with anaplastic thyroid cancer who have received XmAb20717 therapy. VII. To assess the toxicity profile of XmAb20717 in patients with anaplastic thyroid cancer, according to National Cancer Institute (NCI)-Common Terminology Criteria for Adverse Events (CTCAE) version (v)5.0. EXPLORATORY OBJECTIVES: I. To conduct correlative, translational research to identify markers associated with response to XmAb20717 (i.e., neo-epitopes) and to explore the immune microenvironment in patients with anaplastic thyroid cancer and Hurtle cell cancer. II. To administer XmAb20717 to a small, exploratory cohort of patients with Hurtle cell thyroid cancer (HCC) to obtain pilot efficacy, safety, and correlative data for this population. OUTLINE: Patients receive vudalimab intravenously (IV) over 1 hour on days 1 and 15 of each cycle. Cycles repeat every 28 days for up to 24 months in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up every 3 months for 1 year and then every 6 months for 4 years.