Magnetic Resonance Imaging in Measuring the Effect of Cabozantinib in Patients With Castrate Resistant Prostate Cancer

This study is being done to help researchers understand more about prostate cancer that has spread to the bones by using the newest magnetic resonance imaging (MRI) techniques and to better understand the effect of an experimental drug called XL184 (or cabozantinib) on bone disease. The other purposes of the study are to better understand the effect of XL184 on prostate cancer progression, bone pain, and on any cancer cells that patients may have circulating within the blood (called circulating tumor cells)

PRIMARY OBJECTIVES:

I. To determine effect of XL184 on the functional MRI metrics Ktrans and apparent diffusion coefficient (ADC) within castrate resistant prostate cancer bone metastases.

SECONDARY OBJECTIVES:

I. To quantify progression free survival in men with castrate resistant prostate cancer (CRPC) treated with XL184 according to Prostate Cancer Working Group criteria.

II. To correlate and changes in MRI based functional metrics with bone scan, prostate specific antigen (PSA), Response Evaluation Criteria in Solid Tumors (RECIST) response criteria, circulating tumor cells (CTC) number and with changes in pain.

III. To explore c-MET, phospho-c-MET staining on circulating tumor cells as a predictive biomarker for response and duration of response to XL-184.

OUTLINE:

Patients receive cabozantinib orally (PO) once daily (QD). Treatment continues in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed up periodically.

Eligibility Criteria:
Inclusion Criteria:

* Histologically or cytologically confirmed prostate cancer with progressive disease
* Evidence of castration resistance defined as disease progression despite a testosterone level \< 50ng/dL (or surgical castration)
* Evidence of metastatic disease to the bones within the lumbar spine, sacrum, or pelvic bones that is identifiable on screening pelvic MRI
* If patient has had prior pelvis radiation therapy (RT), then bone metastases must be out of radiated port (e.g. lumbar or sacral spine)
* Any prior therapy for castrate disease acceptable other than prior XL184 with a minimum washout of 28 days for any other anticancer therapy
* Patients with castrate resistant disease post antiandrogen therapy/withdrawal must meet at least one of the following criteria:

  * Have not received docetaxel chemotherapy
  * Have received docetaxel chemotherapy but received less then 225mg/m2 cumulative dose
  * Have documented liver metastases
  * Have no pain or pain that does not require a long acting (SR) narcotic
  * Have received mitoxantrone chemotherapy in the past for CRPC

Exclusion Criteria:

* Patients who have had chemotherapy or radiotherapy within 4 weeks prior to entering the study
* Patients who are receiving any other investigational agents
* Prior treatment with other vascular endothelial growth factor (VEGF) or c-MET targeted therapies
* History of hematemesis or hemoptysis
* The subject has uncontrolled or significant intercurrent illness
* The patient requires concomitant treatment, in therapeutic doses, with anticoagulants