Cabozantinib in Recurrent/Metastatic Merkel Cell Carcinoma

Cabozantinib (XL184) is an inhibitor of multiple receptor tyrosine kinases and was approved by the U.S. Food and Drug Administration (FDA) on 29 November 2012 for the treatment of patients with progressive, metastatic medullary thyroid cancer. It is commercially available as COMETRIQ™ in the United States. During the Pre Treatment Period, participants are consented and qualified (screened) for the study. Treatment will be administered on an outpatient basis. Each treatment cycle lasts 28 days, during which time the participant will be taking the study drug, cabozantinib, once daily. The participant will be given a study drug-dosing diary for each treatment cycle. The diary will also include special instructions for taking the study drug. \- Participants will be followed for 8 weeks after removal from study or until death, whichever occurs first. Participants removed from study for unacceptable adverse events will be followed until resolution or stabilization of the adverse event.