OncRef

Clinical Trial: NCT03834493

Study of Pembrolizumab (MK-3475) Plus Enzalutamide Versus Placebo Plus Enzalutamide in Participants With Metastatic Castration-resistant Prostate Cancer (mCRPC) (MK-3475-641/KEYNOTE-641)

Status:

TERMINATED

Phase:

Phase 3

Lead Sponsor:Merck Sharp & Dohme LLC
Information Provided By:Merck Sharp & Dohme LLC
Last Update Posted:2026-09-28

Study Overview

Brief Summary

The purpose of this study is to assess the efficacy and safety of the combination of pembrolizumab (MK-3475) and enzalutamide in the treatment of men with metastatic castration-resistant prostate cancer (mCRPC) who have not received chemotherapy for mCRPC, are abiraterone-naïve, or are intolerant to or progressed on abiraterone acetate. There are two primary study hypotheses.

Hypothesis 1: The combination of pembrolizumab plus enzalutamide is superior to placebo plus enzalutamide with respect to Overall Survival (OS).

Hypothesis 2: The combination of pembrolizumab plus enzalutamide is superior to placebo plus enzalutamide 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.

Official Title

A Phase 3, Randomized, Double-blind Trial of Pembrolizumab (MK-3475) Plus Enzalutamide Versus Placebo Plus Enzalutamide in Participants With Metastatic Castration-Resistant Prostate Cancer (mCRPC) (KEYNOTE-641)

Conditions

Prostatic Neoplasms

Intervention / Treatment

  • Biological: Pembrolizumab
  • Drug: Enzalutamide
  • Drug: Placebo

Other Study ID Numbers

  • 3475-641
  • MK-3475-641
  • KEYNOTE-641
  • 195005
  • 2022-500785-10-00
  • U1111-1278-1151
  • 2018-004117-40
  • 2018

Start Date (Actual)

2019-07-28

Primary Completion Date (Actual)

2022-12-12

Study Completion Date (Actual)

2026-06-08

Enrollment (Actual)

1244

Study Type

Interventional

Phase

Phase 3