ESK981 in Treating Patients With Metastatic Castrate-Resistant Prostate Cancer

Inclusion Criteria: * Have signed an informed consent document indicating that the subject understands the purpose of and procedures required for the study and are willing to participate in the study * Be willing/able to adhere to the prohibitions and restrictions specified in this protocol * Eastern Cooperative Group (ECOG) performance status =\< 1 * Patient must have evidence of castrate resistant prostate cancer as evidenced by a confirmed rising PSA (per PCWG3 criteria) and a castrate serum testosterone level (i.e. =\< 50 mg/dL) * Documented histologically confirmed adenocarcinoma of the prostate * Metastatic prostate cancer (M1) as documented by appropriate medical imaging (i.e. computed tomography \[CT\]-scan, positron emission tomography \[PET\] scan or bone scan) * Treatment failure of either abiraterone and/or enzalutamide as evidenced by a confirmed rising PSA (per PCWG3 criteria) and a castrate serum testosterone level (i.e. =\< 50 mg/dL) while receiving treatment with either abiraterone and/or enzalutamide * Willingness to use contraception by a method that is deemed effective by the Investigator throughout the treatment period and for at least 30 days following the last dose of therapy * Willingness and ability to comply with study procedures and follow-up examination * Able to swallow and retain oral medication Exclusion Criteria: * Current systemic therapy (other than a gonadotrophin releasing hormone \[GnRH\] agonist/antagonist) for CRPC including: * CYP…