Combo of Cabozantinib With Abiraterone in Chemotherapy-Naïve Subjects With Bone-Metastatic CRPC

Inclusion Criteria:

* Histologically or cytologically confirmed adenocarcinoma of the prostate.
* Must be surgically or medically castrated (serum testosterone levels less than or equal to 50 ng/dL)
* Must have castration-resistant prostate cancer (CRPC) with disease progression during LHRH therapy or after a surgical bilateral orchiectomy.
* Bone metastasis related to prostate cancer
* Adequate organ and marrow function
* Capable of understanding and complying with the protocol requirements and signed the informed consent document
* Sexually active subjects and their partners must agree to use medically accepted methods of barrier contraception (eg, male condom or female condom) as well as one other medically accepted method of contraception during the course of the study treatment and for 4 months after the last dose of study treatment.

Exclusion Criteria:

* Any prior treatment with abiraterone, enzalutamide, or any investigational agents blocking androgen receptor (AR) or androgen synthesis.
* Any prior treatment with cabozantinib or participation in a prior clinical trial of cabozantinib.
* Any prior cytotoxic therapy (including estramustine) or biologic therapy for the treatment of prostate cancer (a few exceptions will be allowed)
* Any prior radionuclide therapy (eg, samarium 153, strontium 89, alpharadin)
* Use of investigational agent within 28 days
* Any pathological finding consistent with small cell carcinoma of the prostate
* Known brain metastases or cranial epidural disease
* Diagnosis of another malignancy within 2 years, except for superficial non-melanoma skin cancers, or localized, low grade tumors deemed cured and not treated with systemic therapy