NCT04003636 · CITED IN SOURCE DOCUMENTS

Pembrolizumab (MK-3475) Plus Gemcitabine/Cisplatin Versus Placebo Plus Gemcitabine/Cisplatin for First-Line Advanced and/or Unresectable Biliary Tract Carcinoma (BTC) (MK-3475-966/KEYNOTE-966)

An NCI or FDA source cites this study. A citation does not establish that it applies to an individual diagnosis.

Phase: PHASE3
Status at capture: COMPLETED
Registry last update: 2026-03-24

This is a study of pembrolizumab plus gemcitabine/cisplatin versus placebo plus gemcitabine/cisplatin as first-line therapy in participants with advanced and/or unresectable biliary tract carcinoma. The primary hypothesis is pembrolizumab plus gemcitabine/cisplatin is superior to placebo plus gemcitabine/cisplatin with respect to overall survival (OS).

Open the original ClinicalTrials.gov record → · Download preserved record

What did the study report?

Outcomes, safety and baseline populations are separate source sections. Quality-of-life measures appear under their original outcome titles.

flow

Participant flow

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baseline

Baseline characteristics

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outcome · POSTED

Overall Survival (OS)

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outcome · POSTED

Progression-free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Response Evaluation Criteria in Solid Tumors Version 1.1 (BICR)

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outcome · POSTED

Objective Response Rate (ORR) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review (BICR)

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outcome · POSTED

Duration of Response (DOR) Per RECIST 1.1 as Assessed by BICR

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outcome · POSTED

Number of Participants Who Experience One or More Adverse Events (AE)

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outcome · POSTED

Number of Participants Who Discontinued Study Intervention Due to an AE

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adverse events

Adverse events

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more info

Limitations, agreements, and source contact

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Who could take part

eligibility Criteria: Inclusion Criteria * Has histologically confirmed diagnosis of advanced (metastatic) and/or unresectable (locally advanced) biliary tract cancer (intra-or extrahepatic cholangiocarcinoma or gallbladder cancer) * Has measurable disease based on Response Evaluation Criteria in Solid Tumors (RECIST 1.1), as determined by the site investigator * Participants with a history of hepatitis B or hepatitis C can be enrolled if they meet study criteria * Is able to provide archival tumor tissue sample or newly obtained core or excisional biopsy of a tumor lesion * Has a life expectancy of greater than 3 months * Has adequate organ function Exclusion Criteria * Has had previous systemic therapy for advanced (metastatic) or unresectable (locally advanced) biliary tract cancer (intra-or extra hepatic cholangiocarcinoma or gallbladder cancer) * Has ampullary cancer * Has small cell cancer, neuroendocrine tumors, lymphoma, sarcoma, mixed tumor histology and/or mucinous cystic neoplasms * Has received prior therapy with an anti-programmed cell death 1 (anti-PD-1), anti- programmed cell death ligand 1 or 2 (anti-PD-L1, anti-PD-L2) agent or with an agent directed to another stimulatory or coinhibitory T-cell receptor (e.g., cytotoxic T-lymphocyte-associated protein 4 \[CTLA-4\], OX-40, CD137) * Has a known history of, or any evidence of, central nervous system (CNS) metastases and/or carcinomatous meningitis, as assessed by local site investigator * Has had an allogenic tissue/solid organ transplant
healthy Volunteers: false
minimum Age: 18 Years
sex: ALL
std Ages: ADULT
OLDER_ADULT

Treatment arms and interventions

arm Groups

description
Participants receive pembrolizumab, 200 mg intravenous (IV) infusion, every 3 weeks (Q3W), Day 1 of each 3-week cycle for up to 35 cycles PLUS gemcitabine, 1000 mg/m\^2, IV infusion Q3W, Day 1 and Day 8 of each 3-week cycle until progressive disease or unacceptable toxicity PLUS cisplatin, 25 mg/m\^2 IV infusion, Q3W, Day 1 and Day 8 of each 3-week cycle for up to 8 cycles. Eligible participants who stop the initial course of pembrolizumab with stable disease (SD) or better but progress after discontinuation will initiate a second course of pembrolizumab 200 mg IV Q3W, Day 1 of each 3-week cycle for up to 17 cycles. Treatment with gemcitabine can be stopped at anytime in first or second course due to toxicity or disease progression.
intervention Names
Biological: Pembrolizumab
Drug: Gemcitabine
Drug: Cisplatin
label
Arm A (Pembrolizumab+Chemotherapy)
type
EXPERIMENTAL
description
Participants receive placebo to pembrolizumab, 200 mg IV infusion, every 3 weeks (Q3W), Day 1 of each 3-week cycle for up to 35 cycles PLUS gemcitabine, 1000 mg/m\^2 IV infusion, Q3W, Day 1 and Day 8 of each 3-week cycle until progressive disease or unacceptable toxicity PLUS cisplatin, 25 mg/m\^2 IV infusion, Q3W, Day 1 and Day 8 of each 3-week cycle for up to 8 cycles.
intervention Names
Drug: Gemcitabine
Drug: Cisplatin
Drug: Placebo
label
Arm B (Placebo+Chemotherapy)
type
PLACEBO_COMPARATOR

interventions

arm Group Labels
Arm A (Pembrolizumab+Chemotherapy)
description
Pembrolizumab by intravenous (IV) infusion
name
Pembrolizumab
other Names
MK-3475
type
BIOLOGICAL
arm Group Labels
Arm A (Pembrolizumab+Chemotherapy)
Arm B (Placebo+Chemotherapy)
description
Gemcitabine by IV infusion
name
Gemcitabine
other Names
Gemzar
type
DRUG
arm Group Labels
Arm A (Pembrolizumab+Chemotherapy)
Arm B (Placebo+Chemotherapy)
description
Cisplatin by IV infusion
name
Cisplatin
other Names
Platinol®
Platinol®-AQ
type
DRUG
arm Group Labels
Arm B (Placebo+Chemotherapy)
description
Placebo to pembrolizumab
name
Placebo
type
DRUG

Study design

allocation

RANDOMIZED

intervention Model

PARALLEL

masking Info

masking: TRIPLE
who Masked: PARTICIPANT
INVESTIGATOR
OUTCOMES_ASSESSOR

primary Purpose

TREATMENT

Enrollment

count: 1069
type: ACTUAL

Registered outcome plans (not posted results)

primary Outcomes

description
Overall survival was defined as the time from randomization to death due to any cause.
measure
Overall Survival (OS)
time Frame
Up to approximately 38 months

secondary Outcomes

description
PFS was defined as the time from randomization to the first documented disease progression (PD) or death due to any cause, whichever occurred first. Per RECIST 1.1, PD was defined as ≥20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also have demonstrated an absolute increase of ≥5 mm. The appearance of one or more new lesions was also considered PD. PFS as assessed by BICR per RECIST 1.1 was presented.
measure
Progression-free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Response Evaluation Criteria in Solid Tumors Version 1.1 (BICR)
time Frame
Up to approximately 26 months
description
ORR was defined as the percentage of participants who have a confirmed Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: a ≥30% decrease in the sum of diameters \[SOD\] of target lesions) as assessed by BICR per RECIST 1.1, which was adjusted for this study to allow a maximum of 10 target lesions in total and 5 per organ.
measure
Objective Response Rate (ORR) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review (BICR)
time Frame
Up to approximately 26 months
description
For participants who demonstrated a confirmed CR (disappearance of all target lesions) or PR (at least a 30% decrease in the sum of diameters of target lesions) per RECIST 1.1, DOR was defined as the time from first documented evidence of a CR or PR until PD or death. DOR for participants who had not progressed or died at the time of analysis was to be censored at the date of their last tumor assessment. Per RECIST 1.1, PD was defined as at least a 20% increase in the sum of diameters of target lesions as well as an absolute increase of at least a 5 mm in the sum of diameters. The appearance of one or more new lesions was also considered PD. DOR assessments were based on BICR with confirmation. The DOR as assessed using RECIST 1.1 for all participants who experienced a confirmed CR or PR was presented.
measure
Duration of Response (DOR) Per RECIST 1.1 as Assessed by BICR
time Frame
Up to approximately 38 months
description
An adverse event (AE) was defined as any unfavorable and unintended sign including an abnormal laboratory finding, symptom or disease associated with the use of a medical treatment or procedure, regardless of whether it was considered related to the medical treatment or procedure, that occurred during the course of the study. Number of participants who experienced one or more AEs were reported.
measure
Number of Participants Who Experience One or More Adverse Events (AE)
time Frame
Up to approximately 65 months
description
An AE was defined as any unfavorable and unintended sign including an abnormal laboratory finding, symptom or disease associated with the use of a medical treatment or procedure, regardless of whether it was considered related to the medical treatment or procedure, that occurs during the course of the study. Number of participants who discontinued study intervention due to an AE were reported.
measure
Number of Participants Who Discontinued Study Intervention Due to an AE
time Frame
Up to approximately 63 months

Full study description

brief Summary: This is a study of pembrolizumab plus gemcitabine/cisplatin versus placebo plus gemcitabine/cisplatin as first-line therapy in participants with advanced and/or unresectable biliary tract carcinoma. The primary hypothesis is pembrolizumab plus gemcitabine/cisplatin is superior to placebo plus gemcitabine/cisplatin with respect to overall survival (OS).

Source references

references

citation
Kelley RK, Ueno M, Yoo C, Finn RS, Furuse J, Ren Z, Yau T, Klumpen HJ, Chan SL, Ozaka M, Verslype C, Bouattour M, Park JO, Barajas O, Pelzer U, Valle JW, Yu L, Malhotra U, Siegel AB, Edeline J, Vogel A; KEYNOTE-966 Investigators. Pembrolizumab in combination with gemcitabine and cisplatin compared with gemcitabine and cisplatin alone for patients with advanced biliary tract cancer (KEYNOTE-966): a randomised, double-blind, placebo-controlled, phase 3 trial. Lancet. 2023 Jun 3;401(10391):1853-1865. doi: 10.1016/S0140-6736(23)00727-4. Epub 2023 Apr 16.
pmid
37075781
type
RESULT
citation
Ren Z, Liang T, Gu S, Gou H, Peng C, Pan Y, Song T, Su H, Cao K, Liang H, Ying J, Geng Z, Yu W, Zhao H, Bai Y, Hao C, Mao Y, Li W, Wang L, Li D, Wang W, Li N, Malhotra U, Qin S. First-Line Pembrolizumab Plus Chemotherapy for Advanced Biliary Tract Cancer: China Subgroup Analysis of the Randomized Phase 3 KEYNOTE-966 Study. Adv Ther. 2026 Sep;43(9):3871-3885. doi: 10.1007/s12325-026-03578-4. Epub 2026 May 23.
pmid
42176183
type
DERIVED
citation
Jiang C, Zhou K, Shu P. Cost-effectiveness analysis of pembrolizumab plus chemotherapy as first-line treatment for advanced biliary tract cancer: perspectives from US and Chinese payers. BMJ Open. 2025 Apr 23;15(4):e094047. doi: 10.1136/bmjopen-2024-094047.
pmid
40268484
type
DERIVED
citation
Luo X, Cai T, Wu J, Li X, Wang X, Ma H. Cost-effectiveness of pembrolizumab plus chemotherapy vs. chemotherapy as first-line treatment for advanced biliary tract cancer in China and the US. Front Pharmacol. 2024 Aug 14;15:1393559. doi: 10.3389/fphar.2024.1393559. eCollection 2024.
pmid
39206260
type
DERIVED
citation
Keller HR, Fluke L, Forrester JA, Wolf RF. Identifying Indications for Neoadjuvant Therapy in Cholangiocarcinoma. Oncology (Williston Park). 2024 Apr 11;38(4):160-162. doi: 10.46883/2024.25921017.
pmid
38661512
type
DERIVED