An Extension Treatment Protocol for Subjects Who Have Participated in a Study of Tivozanib Versus Sorafenib in Kidney Carcinoma (Protocol AV-951-09-301).

This is an extension treatment protocol to allow access to tivozanib or sorafenib for subjects enrolled on AV-951-09-301(parent protocol). Subjects who failed sorafenib on the parent protocol will be offered tivozanib. Subjects who were randomized to tivozanib, and demonstrated clinical benefit and acceptable tolerability will be offered long-term access to tivozanib. Subjects who were randomized to sorafenib, and demonstrated clinical benefit and acceptable tolerability will be offered long-term access to sorafenib. Subjects who continue receiving sorafenib on this protocol and progress will be allowed to cross-over to tivozanib.