Adenosine Receptor Antagonist Combination Therapy for Metastatic Castrate Resistant Prostate Cancer

General Inclusion Criteria:

Male participants; age ≥ 18 years
Metastatic castrate-resistant prostate cancer while on anti-androgen treatment with castrate levels of testosterone (≤1.7 nanomoles per liter [nmol/L] or 50 nanograms per deciliter [ng/dL])
Measurable or non-measurable disease as per radiographic evaluation
Participants with measurable disease may require a fresh tumor biopsy at study entry
Eastern Cooperative Oncology Group (ECOG) Performance status of 0 or 1
Life expectancy of at least 3 months
Adequate hematologic and end-organ function
Human immunodeficiency virus (HIV), Hepatitis B, and C test results negative prior to first study treatment

Inclusion Criteria for Participants receiving an enzalutamide-containing treatment

Disease progression after prior treatment with abiraterone

Inclusion Criteria for Participants receiving a docetaxel-containing treatment

Disease progression after prior androgen synthesis inhibitor therapy

Inclusion Criteria for all other Participants

Disease progression after prior androgen synthesis inhibitor treatment and up to 2 prior lines of taxane chemotherapy

General Exclusion Criteria:

Prior treatment with immune checkpoint blockade therapy
Prior anticancer treatment including approved agents, systemic radiotherapy, or investigational therapy, within 2-4 weeks prior first study treatment
Corrected QT interval (QTc) ≥480 msec using Fredericia's QT correction formula (based on an average of triplicate recordings)
Prior allogeneic stem cell or solid organ transplantation
Prior treatment with drugs that stimulate the immune system within 4 weeks prior to first study treatment
Prior treatment with drugs that suppress the immune system within 2 weeks prior to first study treatment
Received a live, attenuated vaccine within 4 weeks prior to first study treatment, or may need to receive a vaccine during study treatment
Presence of metastases in the brain or cancer spreading into the cerebrospinal fluid - CSF (leptomeningeal disease)
Prior pulmonary fibrosis, pneumonia, or pneumonitis
Cancer other than prostate within 2 years prior to study entry, except for some cancers with a low risk of spreading like non-melanoma skin
Prior treatment with an agent targeting the adenosine pathway
No oral or IV antibiotics within 2 weeks prior to first study treatment
No severe infection within 4 weeks prior to first study treatment
No clinically significant cardiac disease
Inability to swallow medications

Exclusion Criteria for Participants receiving an enzalutamide-containing treatment

Prior treatment with docetaxel, cabazitaxel, or other taxane chemotherapy (prior docetaxel [up to 6 cycles] for hormone-sensitive prostate cancer is allowed if the last dose was at least 6 months prior to study treatment initiation)
Prior treatment with enzalutamide or similar therapy other than abiraterone
Active or history of autoimmune disease or immune deficiency
History of severe allergic reactions to antibody therapy
Concomitant use of a medication prohibited by the protocol (including certain transporter substrates as well as known strong CYP3A4 inducers and CYP3A4 inhibitors) within 4 weeks prior to and throughout study treatment

Exclusion Criteria for Participants receiving a docetaxel-containing treatment

Prior treatment with docetaxel, cabazitaxel, or other taxane chemotherapy
Active or history of autoimmune disease or immune deficiency
History of severe allergic reactions to antibody therapy
Concomitant use of a medication prohibited by the protocol (including certain transporter substrates as well as known strong CYP3A4 inducers and CYP3A4 inhibitors) within 4 weeks prior to and throughout study treatment

Exclusion Criteria for all other Participants

Prior treatment with docetaxel, cabazitaxel, topoisomerase 1 inhibitors, or other taxane chemotherapy
Active or history of autoimmune disease or immune deficiency
History of severe allergic reactions to antibody therapy
Concomitant use of a medication prohibited by the protocol (including certain transporter substrates as well as known strong CYP3A4 inducers and CYP3A4 inhibitors) within 4 weeks prior to and throughout study treatment