Conditions: Prostate Cancer
Keywords: liver metastasis lung metastasis metastatic castrate-resistant prostate cancer
Allocation: NA | Intervention model: SINGLE_GROUP
Enrollment: 17
Healthy volunteers: no

Brief summary:
This research study is being done to measure the clinical benefit associated with cabozantinib (XL184) in men who have prostate cancer that has spread to visceral organs (organs other than bone or lymph nodes) and no longer responds to initial hormonal (castration) therapy. This type of prostate cancer is called metastatic, castrate-resistant prostate cancer.

Detailed description:
Cabozantinib (XL184), a multi-targeted tyrosine kinase inhibitor, has demonstrated a powerful clinical phenotype in men with metastatic castrate resistant prostate cancer (mCRPC) both before and after chemotherapy. This phenotype consists of rapid reduction in pain (when present) and improvement in bone scans that may or may not be accompanied by decrease in serum prostate specific antigen (PSA) concentrations. In previous studies of cabozantinib in advanced prostate cancer, patients with visceral disease have been excluded. Hence, this protocol creates a unique opportunity to define the activity of this disease in the population of men with visceral disease - a marker for poorer prognosis in mCRPC.

Primary Objectives:

\- To assess the clinical benefit (complete response + partial response + stable disease) of cabozantinib in patients with mCRPC with visceral metastases.

Secondary Objectives:

* To assess the impact of cabozantinib on numbers live circulating tumor cells (CTCs) using NanoVelcro Chips
* To test the feasibility of measuring variation in gene expression in circulating tumor cells (CTCs) in response to therapy.
* To determine if there is an impact of cabozantinib on live circulating tumor cell (CTC) number and patterns of gene expression.
* To measure the impact of cabozantinib on serum HGF (hepatocyte growth factor) and VEGF (vascular endothelial growth factor) levels in men with metastatic, castration-resistant prostate cancer (mCRPC).
* To assess the safety and tolerability of lower doses (i.e. doses below 100 mg daily) of cabozantinib in mCRPC with visceral involvement.
* To collect blood, urine, tissue, and plasma which may be used determine if there are germline genetic variations that correlate with toxicity.
* To pilot correlations between molecular content between circulating tumor cells (CTCs), large oncosomes, and tumor tissue.

Arms:
arm 1: Cabozantinib 60mg orally daily until disease progression

Interventions: intervention 1: Cabozantinib
Intervention descriptions: intervention 1: Cabozantinib 60 mg daily (oral). Subjects may continue to receive study treatment until they experience unacceptable drug-related toxicity or disease progression.

Protocol document: