A Study of Niraparib Combination Therapies for the Treatment of Metastatic Castration-Resistant Prostate Cancer

Inclusion Criteria for Combination 3:

Diagnosed with mCRPC, who in the opinion of the investigator may benefit from treatment in Combination 3 of this study
Able to continue gonadotropin releasing hormone analogue (GnRHa) therapy during the study if not surgically castrate (that is, subjects who has not undergone bilateral orchiectomy).
Eastern Cooperative Oncology Group Performance Status (ECOG PS) of less than or equal to (<=) 1
Toxicity associated with prior chemotherapy or radiotherapy has resolved to Grade <= 1 (except alopecia or Grade <= 2 neuropathy) at screening
Participant must agree not to donate sperm while on study treatment, and for 3 months following the last dose of study treatment

Exclusion Criteria:

History or current diagnosis of myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML)
Active malignancies (that is, progressing or requiring treatment change in the last 24 months) other than the disease being treated under study. The only allowed exceptions are: non-muscle invasive bladder cancer; skin cancer (non-melanoma or melanoma); breast cancer; malignancy that is considered cured with minimal risk of recurrence
Active infection requiring systemic therapy
Allergies, hypersensitivity, or intolerance to niraparib or the corresponding excipients

Combination 3:

Symptomatic brain metastases
Prior disease progression during combination treatment with AA and poly (adenosine diphosphate [ADP]-ribose) polymerase inhibitor (PARPi). Prior discontinuation of treatment with AA or PARPi due to AA- or PARPi-related toxicity