Dorff TB - TRC105, a monoclonal antibody against endoglin, failed to improve PFS when added to bevacizumab. 

Methods
Eligible patients with metastatic RCC who had received 1-4 prior lines of therapy, including VEGF-targeted agents, were randomized 1:1 to receive bevacizumab (10 mg/kg intravenously every 2 weeks; arm A) or the same plus TRC105 (10 mg/kg intravenously every 2 weeks; arm B). 
The primary endpoint was (PFS at 12 and 24 weeks. 

Results
59 patients were enrolled (28 on arm A and 31 on arm B), and 1 patient on each arm had a confirmed partial response.
The median PFS for bevacizumab alone was 4.6 months compared with 2.8 for bevacizumab plus TRC105.
Baseline serum TGF-beta levels below the median (<10.6 ng/mL) were associated with longer median PFS (5.6 vs. 2.1 months).