A Phase 2 Study Of Cabozantinib As First-Line Treatment In Collecting Ducts Renal Cell Carcinoma: The Bonsai Trial.

TPS709Background: Collecting ducts carcinoma (CDC) is a rare and aggressive form of renal cell carcinoma, characterized by extremely poor prognosis and resistance to agents effective in other forms of RCC. We hypothesized that cabozantinib, an inhibitor of multiple kinases including VEGFR 2, MET and AXL, may be superior in terms of efficacy to other angiogenesis inhibitors in the treatment of CDC due to its high-spectrum of activity against multiple and non-redundant oncogenic pathways. Methods: The BONSAI study is a prospective, single-centre, single-arm phase II trial evaluating cabozantinib in patients with untreated locally advanced or metastatic CDC. Cabozantinib will be administered at the dose of 60 mg orally once daily until the evidence of disease progression (PD) evaluated by RECIST 1.1 or unacceptable toxicity. Primary objective is the evaluation of objective response rate (ORR). Secondary endpoints are progression-free survival (PFS), overall survival (OS) and safety profile of cabozantinib. E...