A Phase 3, Randomized, Open-label Study of MK-5684 Versus Alternative Abiraterone Acetate or Enzalutamide in Participants With Metastatic Castration-resistant Prostate Cancer (mCRPC) That Progressed On or After Prior Treatment With One Next-generation Hormonal Agent (NHA)

• Have histologically or cytologically confirmed adenocarcinoma of the prostate without small cell histology
• Has current evidence of metastatic disease documented by either bone lesions on bone scan and/or soft tissue disease shown by computed tomography scan (CT)/magnetic resonance imaging (MRI)
• Has prostate cancer progression while receiving androgen deprivation therapy (ADT) (or post bilateral orchiectomy) within 6 months before Screening
• Has disease that progressed during or after treatment with one next-generation hormonal agent (NHA) for hormone sensitive prostate cancer (HSPC) metastatic hormone sensitive prostate cancer (mHSPC) or non metastatic hormone sensitive prostate cancer (nmHSPC), for at least 8 weeks (at least 14 weeks for participants with bone progression) Note: Participants may have received abiraterone acetate and docetaxel or darolutamide and docetaxel for HSPC. However, participants must have received no more than six cycles of docetaxel and had no radiographic disease progression while receiving docetaxel
• ECOG PS 0-1
• Has ongoing androgen deprivation with serum testosterone <50 ng/dL (<1.7 nM)
• Has had prior treatment with Poly polymerase inhibitors (PARPi) or were deemed ineligible to receive treatment by the investigator or have refused PARPi treatment
• Has adequate organ function
• Has provided tumor tissue from a fresh core or excisional biopsy from soft tissue not previously irradiated. Samples from tumors progressing at a prior site of radiation are allowed
• Participants who have adverse event (AEs) due to previous anticancer therapies must have recovered to ≤Grade 1 or baseline. Participants with endocrine-related AEs who are adequately treated with hormone replacement therapy (HRT) or participants who have ≤Grade 2 neuropathy are eligible
• Human immunodeficiency virus (HIV)-infected participants must have well controlled HIV on antiretroviral therapy (ART)
• No presence of gastrointestinal condition
• No history of pituitary dysfunction
• No poorly controlled diabetes mellitus
• No active or unstable cardio/cerebro-vascular disease, including thromboembolic events
• Has not received a taxane-based chemotherapy and or NHA for metastatic castration-resistant prostate cancer (mCRPC)
• Has not received prior treatment with radium for prostate cancer
• Does not have a "superscan" bone scan defined as an intense symmetric activity in the bones and diminished renal parenchymal activity on baseline bone scan such that the presence of additional metastases in the future could not be evaluated
• Has known additional malignancy that is progressing or has required active treatment within the past 3 years
• No known active central nervous system (CNS) metastases

• Primary
  • radiologic PFS
  • OS
• Secondary
  • TFST
  • ORR
  • DOR
  • Time to pain progression
  • Time to PSA progression
  • Time to first symptomatic skeletal related event
  • Safety