Bevacizumab With or Without TRC105 in Treating Patients With Metastatic Kidney Cancer

PRIMARY OBJECTIVES: I. To compare the progression-free survival at 12 and 24 weeks for bevacizumab alone or in combination with TRC105 (anti-endoglin monoclonal antibody TRC105). SECONDARY OBJECTIVES: I. Toxicity and Response Evaluation Criteria in Solid Tumors (RECIST) response rate for the combination compared to single agent bevacizumab. TERTIARY OBJECTIVES: I. To evaluate tumor tissue expression of endoglin (CD105), transforming growth factor, beta receptor II (TGFBR2), activin A receptor type II-like 1 (ACVRL1) and transforming growth factor, beta receptor 1 (TGFBR1) kinase from pre- and post-treatment tissue samples in order to determine whether CD105 and stem cell activation occurs after exposure to anti-vascular endothelial growth factor (VEGF) therapy as predicted by laboratory models, and whether exposure to anti-endoglin monoclonal antibody TRC105 affects these changes. II. To compare the soluble CD105 levels at baseline and after treatment between the group receiving bevacizumab alone and the group receiving bevacizumab in combination with anti-endoglin monoclonal antibody TRC105. III. To compare TGFBR2 levels at baseline and after treatment between the group receiving bevacizumab alone and the group receiving bevacizumab in combination with anti-endoglin monoclonal antibody TRC105. IV. To evaluate whether circulating tumor cells (CTCs) can be detected in this patient population using parylene membrane filter technology, and whether changes in CTC counts and CD105 expression on CTCs during therapy correspond to imaging and clinical response. OUTLINE: Patients are randomized to 1 of 2 treatment arms. ARM I: Patients receive bevacizumab intravenously (IV) over 30-90 minutes on days 1 and 15. ARM II: Patients receive bevacizumab as in Arm I and anti-endoglin monoclonal antibody TRC105 IV over 1-4 hours on days 1, 8, 15, and 22. In both arms, treatment repeats every 28 days for up to 12 courses in the absence of disease progression or unacceptable toxicity. After completion of study therapy, patients are followed up for 4 weeks.