# Perioperative Pembrolizumab (MK-3475) Plus Neoadjuvant Chemotherapy Versus Perioperative Placebo Plus Neoadjuvant Chemotherapy for Cisplatin-eligible Muscle-invasive Bladder Cancer (MIBC) (MK-3475-866/KEYNOTE-866)

> **NCT03924856** · PHASE3 · ACTIVE_NOT_RECRUITING · sponsor: **Merck Sharp & Dohme LLC** · enrollment: 907 (actual)

## Conditions studied

- Bladder Cancer

## Interventions

- **DRUG:** Pembrolizumab
- **DRUG:** Gemcitabine
- **DRUG:** Cisplatin
- **PROCEDURE:** Surgery (radical cystectomy (RC) plus Pelvic Lymph Node Dissection [PLND])
- **DRUG:** Placebo

## Key facts

- **NCT ID:** NCT03924856
- **Lead sponsor:** Merck Sharp & Dohme LLC
- **Sponsor class:** INDUSTRY
- **Phase:** PHASE3
- **Study type:** INTERVENTIONAL
- **Status:** ACTIVE_NOT_RECRUITING
- **Start date:** 2019-06-13
- **Primary completion:** 2026-01-26
- **Final completion:** 2026-09-01
- **Target enrollment:** 907 (ACTUAL)
- **Last updated:** 2025-08-28


## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT03924856

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT03924856, "Perioperative Pembrolizumab (MK-3475) Plus Neoadjuvant Chemotherapy Versus Perioperative Placebo Plus Neoadjuvant Chemotherapy for Cisplatin-eligible Muscle-invasive Bladder Cancer (MIBC) (MK-3475-866/KEYNOTE-866)". Retrieved via AI Analytics 2026-06-02 from https://api.ai-analytics.org/clinical/NCT03924856. Licensed CC0.

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