This is a Phase II, open-label study of TRC105 (anti-endoglin antibody) in combination with abiraterone or enzalutamide in metastatic, castration-resistant prostate cancer patients who are taking either abiraterone or enzalutamide and showing signs of biochemical progression without radiographic progression. A patient who is progressing on AR-therapy will continue the same AR-therapy on study with the addition of TRC105. The two arms will accrue in parallel and independently.~There will be a 2-week washout of the active AR-targeted therapy prior to initiation of combination therapy. Tumor response should be assessed at a frequency of 8 weeks by CT/MRI chest, abdomen and pelvis as well as bone scan. Patients may continue on therapy until radiographic progression by RECIST 1.1 or PCWG3 criteria.
This research study is being done to measure the clinical benefit of TRC105 in combination with abiraterone or enzalutamide in metastatic, castration-resistant prostate cancer patients who are taking either abiraterone or enzalutamide and showing signs of biochemical progression without radiographic progression. A patient who is progressing on AR-therapy will continue the same AR-therapy on study with the addition of TRC105. The two arms will accrue in parallel and independently.