Zanzalintinib Plus Cemiplimab for the Treatment of BRAF Wild-Type Anaplastic Thyroid Cancer

Inclusion Criteria: * Male/female participants who are at least 18 years of age on the day of signing informed consent * Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2. Evaluation of ECOG is to be performed within 7 days prior to the date of allocation/randomization. * Pathologic findings supporting the clinical impression of anaplastic thyroid carcinoma. Diagnosis may include consistent with or suggestive of terminology associated with anaplastic thyroid carcinoma, undifferentiated carcinoma, squamous carcinoma; carcinoma with spindled, giant cell, or epithelial features; poorly differentiated carcinoma with pleomorphism, extensive necrosis with tumor cells present. * Patients deemed to have unresectable locoregional disease (stage IVB) or metastatic disease (stage IVC). Patients who are unwilling to undergo surgery or external beam radiation are also eligible. * Patients with BRAF-wild type ATC will be eligible for this study. Patients with a BRAFV600E mutation who are unable to receive the FDA approved drugs, dabrafenib/trametinib, are also eligible as long as this is documented. * Unless clinically contraindicated, all patients with active neck disease who have not received prior neck radiation will be considered for palliative-dose EBRT to the neck (preferably 14 Gy, but 7 to 30 Gy is acceptable) within one month prior to the initiation of study drugs. All patients eligible for palliative neck EBRT who do not undergo radiation will need t…