# 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)

> **NCT03834493** · PHASE3 · ACTIVE_NOT_RECRUITING · sponsor: **Merck Sharp & Dohme LLC** · enrollment: 1244 (actual)

## Conditions studied

- Prostatic Neoplasms

## Interventions

- **BIOLOGICAL:** Pembrolizumab
- **DRUG:** Enzalutamide
- **DRUG:** Placebo

## Key facts

- **NCT ID:** NCT03834493
- **Lead sponsor:** Merck Sharp & Dohme LLC
- **Sponsor class:** INDUSTRY
- **Phase:** PHASE3
- **Study type:** INTERVENTIONAL
- **Status:** ACTIVE_NOT_RECRUITING
- **Start date:** 2019-07-28
- **Primary completion:** 2022-12-12
- **Final completion:** 2026-05-29
- **Target enrollment:** 1244 (ACTUAL)
- **Last updated:** 2025-07-18


## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT03834493

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration 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)". Retrieved via AI Analytics 2026-06-23 from https://api.ai-analytics.org/clinical/NCT03834493. Licensed CC0.

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