Last updated on August 2019

Study of Pembrolizumab (MK-3475) Plus Docetaxel Versus Placebo Plus Docetaxel in Chemotherapy-na ve Metastatic Castration-resistant Prostate Cancer (mCRPC) (MK-3475-921/KEYNOTE-921)


Are you eligible to participate in this study?

You may be eligible for this study if you meet the following criteria:

  • Conditions: Malignant neoplasm of prostate
  • Age: Between 18 - 100 Years
  • Gender: Male

Inclusion Criteria:

  • Has histologically- or cytologically-confirmed adenocarcinoma of the prostate without small cell histology
  • Has prostate cancer progression while on androgen deprivation therapy (or post bilateral orchiectomy) within 6 months prior to screening
  • Has current evidence of metastatic disease documented by either bone lesions on bone scan and/or soft tissue disease by computed tomography/magnetic resonance imaging (CT/MRI)
  • Has received prior treatment with either abiraterone acetate or enzalutamide (but not both) in the pre-chemotherapy mCRPC state and either a) progressed through treatment OR b) has become intolerant of the drug
  • Has ongoing androgen deprivation with serum testosterone <50 ng/mL (<2.0 nM)
  • Participants receiving bone resorptive therapy (including, but not limited to, bisphosphonate or denosumab) must have been on stable doses prior to randomization
  • Participants must agree to the following during the study treatment period and for 120 days after the last dose of study treatment: Refrain from donating sperm PLUS Use contraception unless confirmed to be azoospermic (vasectomized or secondary to medical cause)
  • Participants must agree to use male condom when engaging in any activity that allows for passage of ejaculate to another person of any sex
  • Has provided newly obtained core or excisional biopsy (obtained within 12 months of screening) from soft tissue not previously irradiated (samples from tumors progressing in a prior site of radiation are allowed). Participants with bone only or bone predominant disease may provide a bone biopsy sample
  • Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 assessed within 7 days of randomization

Exclusion Criteria:

  • Has a known additional malignancy that is progressing or has required active treatment in the last 3 years
  • Has an active autoimmune disease that has required systemic treatment in past 2 years
  • Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy
  • Has undergone major surgery including local prostate intervention (excluding prostate biopsy) within 28 days prior to randomization and not recovered adequately from the toxicities and/or complications
  • Has a gastrointestinal disorder affecting absorption or is unable to swallow tablets/capsules
  • Has an active infection (including tuberculosis) requiring systemic therapy
  • Has a history of (non-infectious) pneumonitis that required steroids or current pneumonitis
  • Has known active human immunodeficiency virus (HIV), hepatitis B virus (HBV) or hepatitis C virus (HCV) infection
  • Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis
  • Has severe hypersensitivity (Grade 3) to pembrolizumab and/or any of its excipients
  • Has symptomatic congestive heart failure (New York Heart Association Class III or IV heart disease)
  • Has had a prior anti-cancer monoclonal antibody (mAb) prior to randomization or who has not recovered (i.e., Grade 1 or at baseline) from AEs due to mAbs
  • Has used herbal products that may have hormonal anti-prostate cancer activity and/or are known to decrease PSA levels (e.g. saw palmetto) prior to randomization
  • Has received prior treatment with radium or other therapeutic radiopharmaceuticals for prostate cancer
  • Has received prior therapy with an anti-programmed cell death-1 (anti-PD-1), anti-programmed cell death-ligand 1 (anti-PD-L1), or anti PD-L2 agent or with an agent directed to another stimulatory or co-inhibitory T-cell receptor (e.g., cytotoxic T-lymphocyte-associated protein 4 [CTLA-4], OX-40, CD137)
  • Has received prior treatment with docetaxel or another chemotherapy agent for mCRPC
  • Has had prior treatment with apalutamide or darolutamide
  • Has hypersensitivity to docetaxel or polysorbate 80
  • Is currently receiving either strong or moderate inhibitors of cytochrome P450 (CYP)3A4 that cannot be discontinued for the duration of the study
  • Has had prior treatment with abiraterone acetate and progressed in the hormone-sensitive setting
  • Has received prior targeted small molecule therapy or abiraterone acetate or enzalutamide within 4 weeks prior to the first dose of study treatment, or has not recovered (i.e., Grade 1 or at baseline) from AEs due to a previously administered agent
  • Has received prior radiotherapy to within 2 weeks of start of study treatment. Participants must have recovered from all radiation-related toxicities, not require corticosteroids, and not have had radiation pneumonitis
  • Has received a live vaccine within 30 days prior to randomization
  • Is currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks prior to the first dose of study treatment
  • Has a "superscan" bone scan
  • Is expecting to conceive or father children within the projected duration of the study, starting with the screening visit through 120 days after the last dose of study treatment
  • Has had an allogenic tissue/solid organ transplant

Recruitment Status: Open


Brief Description Eligibility Contact Research Team


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