- Phase Ib dose escalation cohort study: subjects with histologically assessed metastatic clear cell RCC (defined as more than 50% clear cell component) after failure of at least one systemic therapy for metastatic disease (including, but not limited to prior therapy with interleukin 2, interferon, bevacizumab, VEGF TKI, and mTOR) for metastatic disease. NOTE: A biopsy to prove metastatic disease is not required.