CI

At a glance

ClinicalIndex Comparison Record
Phase 3Completed· 1,030 enrolled
Drug / intervention
Pembrolizumab +4 morebiological
Likely dose
Not stated in record
Structured eligibility isn't available for this trial yet — see the full criteria in the Eligibility tab below.

Standardized by ClinicalIndex from the ClinicalTrials.gov record · verify against the source.

Search/NCT03834506
NCT03834506Phase 3Completed

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)

Merck Sharp & Dohme LLC·interventional·Posted Feb 8, 2019·Updated Jul 18, 2025

In Brief

A Phase 3 clinical trial evaluating Pembrolizumab, Docetaxel, and 3 other interventions for Prostatic Neoplasms. Completed, enrolled 1,030 participants across 215 sites in 21 countries.

Detailed Summary

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 Details

Study Typeinterventional
Allocation--
Masking--
Primary Purpose--
CountriesArgentina, Australia, Austria, Brazil, Canada, Chile, China, Colombia, France, Germany, Ireland, Israel, Italy, Japan, Netherlands, Russia, South Korea, Spain, Taiwan, United Kingdom, United States
Collaborators--

Timeline

Phase 3CompletedFinished
20192020202120222023202420252026
First PostedFeb 8, 2019
Enrollment StartMay 2, 2019
Primary CompletionJun 20, 2022
Study CompletionJul 18, 2023
TodayJul 2, 2026
Enrollment to primary: 3.1 yearsPosted 7.4 years ago

Interventions

Pembrolizumabbiological

IV infusion

Docetaxeldrug

IV infusion

Prednisonedrug

Oral tablets

Placebodrug

IV infusion

Dexamethasonedrug

Oral tablets