Study of Pembrolizumab (MK-3475) Plus Docetaxel Versus Placebo Plus Docetaxel in Chemotherapy-naïve Metastatic Castration-resistant Prostate Cancer (mCRPC) (MK-3475-921/KEYNOTE-921)
Public ClinicalTrials.gov record NCT03834506. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.
Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.
Official title
A Phase 3, Randomized, Double-blind Study of Pembrolizumab (MK-3475) Plus Docetaxel Plus Prednisone Versus Placebo Plus Docetaxel Plus Prednisone in Participants With Chemotherapy-naïve Metastatic Castration-Resistant Prostate Cancer (mCRPC) Who Have Progressed on a Next Generation Hormonal Agent (NHA) (KEYNOTE-921)
Brief summary
Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.
The purpose of this study is to assess the efficacy and safety of the combination of pembrolizumab (MK-3475) and docetaxel in the treatment of men with metastatic castration-resistant prostate cancer (mCRPC) who have not received chemotherapy for mCRPC but have progressed on or are intolerant to Next Generation Hormonal Agent (NHA). There are two primary study hypotheses. Hypothesis 1: The combination of pembrolizumab plus docetaxel plus prednisone is superior to placebo plus docetaxel plus prednisone with respect to Overall Survival (OS). Hypothesis 2: The combination of pembrolizumab plus docetaxel plus prednisone is superior to placebo plus docetaxel plus prednisone with respect to Radiographic Progression-free Survival (rPFS) per Prostate Cancer Working Group (PCWG)-modified Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as assessed by blinded independent central review.
Study identification
- NCT ID
- NCT03834506
- Recruitment status
- Completed
- Study type
- Interventional
- Phase
- Phase 3
- Enrollment
- 1,030 participants
Conditions and interventions
Conditions
Interventions
- Pembrolizumab Biological
- Docetaxel Drug
- Prednisone Drug
- Placebo Drug
- Dexamethasone Drug
Biological · Drug
Eligibility (public fields only)
- Age range
- 18 Years and older
- Sex
- Male
- Healthy volunteers
- Healthy volunteers not accepted
This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.
Study timeline
- Start date
- May 2, 2019 (Actual)
- Primary completion
- Jun 20, 2022 (Actual)
- Completion
- Jul 18, 2023 (Actual)
- Last update posted
- Jul 18, 2025
2019 – 2023
United States locations
- U.S. sites
- 28
- U.S. states
- 20
- U.S. cities
- 27
| Facility | City | State | ZIP | Site status |
|---|---|---|---|---|
| University of South Alabama, Mitchell Cancer Institute ( Site 0065) | Mobile | Alabama | 36604 | — |
| St. Joseph Heritage Healthcare ( Site 0069) | Fullerton | California | 92835 | — |
| University of Southern California Norris Comprehensive Cancer Center ( Site 0061) | Los Angeles | California | 90033 | — |
| USC Norris Oncology Hematology Newport Beach ( Site 0093) | Newport Beach | California | 92663 | — |
| University of California San Francisco ( Site 0023) | San Francisco | California | 94158 | — |
| University of Colorado Cancer Center ( Site 0022) | Aurora | Colorado | 80045 | — |
| Yale Cancer Center ( Site 0038) | New Haven | Connecticut | 06510 | — |
| Moffitt Cancer Center ( Site 0080) | Tampa | Florida | 33612 | — |
| Georgia Cancer Center at Augusta University ( Site 0026) | Augusta | Georgia | 30912 | — |
| Mount Sinai Hospital Medical Center ( Site 0042) | Chicago | Illinois | 60608 | — |
| Methodist Hospital- Merriillville ( Site 0008) | Merrillville | Indiana | 46410 | — |
| Karmanos Cancer Institute ( Site 0077) | Detroit | Michigan | 48201 | — |
| Henry Ford Health System ( Site 0039) | Detroit | Michigan | 48202-2608 | — |
| Cancer & Hematology Centers of Western Michigan ( Site 0013) | Grand Rapids | Michigan | 49503 | — |
| Washington University School of Medicine ( Site 0057) | St Louis | Missouri | 63110 | — |
| St. Vincent Frontier Cancer Center ( Site 0016) | Billings | Montana | 59102 | — |
| Nebraska Cancer Specialists ( Site 0034) | Omaha | Nebraska | 68130 | — |
| Comprehensive Cancer Centers of Nevada ( Site 0092) | Las Vegas | Nevada | 89169 | — |
| John Theurer Cancer Center at Hackensack University Medical Center ( Site 0004) | Hackensack | New Jersey | 07601 | — |
| Associated Medical Professionals of NY ( Site 0060) | Syracuse | New York | 13210 | — |
| Duke Cancer Center ( Site 0010) | Durham | North Carolina | 27710 | — |
| W. G. Bill Hefner VA Medical Center ( Site 0029) | Salisbury | North Carolina | 28144 | — |
| University Hospitals Cleveland Medical Center ( Site 0036) | Cleveland | Ohio | 44106 | — |
| Oregon Health Sciences University ( Site 0031) | Portland | Oregon | 97239 | — |
| Carolina Urologic Research Center ( Site 0070) | Myrtle Beach | South Carolina | 29572 | — |
| Inova Schar Cancer Institute ( Site 0006) | Fairfax | Virginia | 22031-4867 | — |
| Virginia Cancer Institute ( Site 0052) | Richmond | Virginia | 23230 | — |
| Blue Ridge Cancer Care ( Site 0086) | Roanoke | Virginia | 24014 | — |
Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.
Non-U.S. locations
This page focuses on the U.S. directory. The official record also lists 187 non-U.S. sites.
About this trial record page
- What this page shows
- Public field values for ClinicalTrials.gov record NCT03834506, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
- What this page does not do
- No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
- Where the data comes from
- Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
- Last refresh
- Last update posted Jul 18, 2025 · Synced Oct 20, 2026
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Open the official record
The complete public registry record, listed eligibility criteria, and available contact information for NCT03834506 live on ClinicalTrials.gov.