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Colorectal NeoplasmsPhase 3NCT05239741

Study of Pembrolizumab (MK-3475) Versus Chemotherapy in Chinese Participants With Stage IV Colorectal Cancer (MK-3475-C66)

A Phase 3 study testing Pembrolizumab, Oxaliplatin and Leucovorin in people with Colorectal Neoplasms, run by Merck Sharp & Dohme LLC at 32 sites in China.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
Search all trials

Trial summary

In this study, Chinese participants with MSI-H or dMMR advanced colorectal cancer will be assigned to receive either pembrolizumab or the Investigator's choice of 1 of 6 standard of care (SOC) chemotherapy regimens for treatment. There is no hypothesis testing for this study. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Colorectal Neoplasms
What is being tested?
Pembrolizumab, Oxaliplatin and Leucovorin
Type of treatment
Injection or infusion
Could I receive a placebo?
No, everyone receives an active treatment
How many people
100 participants
Where
32 sitesChina
Study dates
2 Apr 2022to 19 Sep 2028
Phase
Phase 3
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Has a histologically confirmed diagnosis of colorectal adenocarcinoma that is at stage IV (as defined by American Joint Committee on Cancer eighth edition) [National Comprehensive Cancer Network 2018]
  • Has centrally confirmed Microsatellite Instability-High/Mismatch Repair Deficient (MSI-H/dMMR) status
  • Has centrally confirmed RAS and BRAF mutation status
  • A woman of child-bearing potential (WOCBP) must have a negative highly sensitive pregnancy test (urine or serum as required by local regulations) within 24 hours for urine or within 72 hours for serum before the first dose of study intervention.
  • Has measurable disease per Response Evaluation Criteria In Solid Tumors (RECIST) 1.1 as assessed by the local site investigator/radiology
  • Must provide an archival tumor tissue sample or newly obtained core or excisional biopsy of a tumor lesion not previously irradiated.
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  • Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1 within 3 days before randomization
  • Has a life expectancy of at least 3 months
  • Has received Hepatitis B Virus (HBV) antiviral therapy for at least 4 weeks, and have undetectable hepatitis B virus (HBV) viral load prior to randomization if hepatitis B surface antigen (HBsAg) positive
  • Has an undetectable Hepatitis C Virus (HCV) viral load if HCV infected
  • Has well controlled Human Immunodeficiency Virus (HIV) on antiretroviral therapy (ART) if HIV infected

Who cannot join

  • Has received prior systemic therapy for stage IV colorectal cancer (CRC). Participants may have received prior adjuvant/neoadjuvant chemotherapy for CRC as long as it was completed at least 6 months prior to randomization
  • Has undergone major operation within 4 weeks of randomization or has not adequately recovered from major surgery or has ongoing surgical complications
  • Has received prior therapy with an anti-programmed cell death 1 protein (anti-PD-1), anti-programmed cell death ligand 1 (anti-PD-L1), or anti-programmed cell death ligand 2 (anti PD-L2) agent or with an agent directed to another stimulatory or coinhibitory T-cell receptor (eg, cytotoxic T-lymphocyte-associated protein 4 [CTLA-4], tumor necrosis factor receptor superfamily, member 4 [OX 40], tumor necrosis factor receptor superfamily member 9 [CD137])
  • Has received prior radiotherapy within 2 weeks of start of study intervention or has radiation-related toxicities, requiring corticosteroids
  • Has received a live or live-attenuated vaccine within 30 days before the first dose of study intervention
  • Has received an investigational agent or has used an investigational device within 4 weeks prior to study intervention administration.
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  • Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior to the first dose of study medication
  • Has a known additional malignancy that is progressing or has required active treatment within the past 5 years, with the exception of basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or carcinoma in situ (eg, breast carcinoma, cervical cancer in situ) that have undergone potentially curative therapy are not excluded
  • Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis
  • Has severe hypersensitivity (≥Grade 3) to pembrolizumab and/or any of its excipients
  • Has an active autoimmune disease that has required systemic treatment in past 2 years
  • Has a history of (noninfectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease
  • Has an active infection requiring systemic therapy (eg, tuberculosis, known viral or bacterial infection)
  • Has HIV-infection with a history of Kaposi's sarcoma or Multicentric Castleman's Disease
  • Has had an allogenic tissue/solid organ transplant

Trial locations and contacts

32 sites in 1 country.

32 sites in 1 country

China32 sites

  • Beijing Cancer hospital-Digestive Oncology ( Site 0001)

    Beijing, Beijing Municipality, 100142

  • Beijing Peking Union Medical College Hospital-Medical Oncology ( Site 0011)

    Beijing, Beijing Municipality, 100730

  • The Third Xiangya Hospital of Central South University ( Site 0031)

    Changsha, Hunan, 410013

  • Sichuan Cancer Hospital. ( Site 0050)

    Chengdu, Sichuan, 610041

  • West China Hospital, Sichuan University ( Site 0044)

    Chengdu, Sichuan, 610066

  • The First Affiliated Hospital of Chongqing Medical University ( Site 0051)

    Chongqing, Chongqing Municipality, 400016

  • Chongqing University Cancer Hospital-Medical Oncology ( Site 0012)

    Chongqing, Chongqing Municipality, 400030

  • Fujian Provincial Cancer Hospital ( Site 0009)

    Fuzhou, Fujian, 350014

  • Sun Yat-sen University Cancer Center ( Site 0047)

    Guangzhou, Guangdong, 510060

  • Guangdong Provincial People's Hospital ( Site 0035)

    Guangzhou, Guangdong, 510080

  • The First Affiliated Hospital, Sun Yat-sen University ( Site 0014)

    Guangzhou, Guangdong, 510080

  • The Sixth Affiliated Hospital of Sun Yat-sen University-Oncology ( Site 0048)

    Guangzhou, Guangdong, 510655

  • Zhejiang Cancer Hospital-oncology-abdominal neoplasms ( Site 0028)

    Hangzhou, Zhejiang, 310022

  • Harbin Medical University Cancer Hospital ( Site 0007)

    Harbin, Heilongjiang, 150081

  • The Affiliated Jiangyin Hospital of Southeast University Medical College ( Site 0037)

    Jiangyin, Jiangsu, 214400

  • Jinan Central Hospital-oncology department ( Site 0021)

    Jinan, Shandong, 250013

  • Shandong Cancer Hospital ( Site 0041)

    Jinan, Shandong, 250117

  • Yunnan Province Cancer Hospital-Colorectal surgery ( Site 0006)

    Kunming, Yunnan, 650106

  • Nanjing Drum Tower Hospital The Affiliated Hospital of Nanjing University Medical School-Oncology ( Site 0002)

    Nanjing, Jiangsu, 210008

  • Guangxi Medical University Affiliated Tumor Hospital ( Site 0039)

    Nanning, Guangxi, 530200

  • Shanghai Changhai Hospital ( Site 0024)

    Shanghai, Shanghai Municipality, 200433

  • Shanghai East Hospital ( Site 0022)

    Shanghai, Shanghai Municipality, 201200

  • Fudan University Shanghai Cancer Center-Oncology ( Site 0046)

    Shanghai, Shanghai Municipality, 201321

  • Cancer Hospital of Shantou University Medical College ( Site 0036)

    Shantou, Guangdong, 515041

  • The first affiliated hospital of China medical university ( Site 0043)

    Shemyang, Liaoning, 110001

  • Shanxi Cancer Hospital ( Site 0032)

    Taiyuan, Shanxi, 030000

  • Tianjin Medical University Cancer Institute and Hospital-Gastric oncology ( Site 0019)

    Tianjin, Beijing Municipality

  • The Affiliated Cancer Hospital of Xinjiang Medical University ( Site 0049)

    Ürümqi, Xinjiang, 830000

  • Tongji Hospital Tongji Medical,Science & Technology-oncology ( Site 0018)

    Wuhan, Hubei, 430000

  • Wuhan Union Hospital Cancer Center-Cancer Center ( Site 0008)

    Wuhan, Hubei, 430022

  • Tangdu Hospital of Fourth Military Medical University of Chi-General Surgery ( Site 0045)

    Xi'an, Shaanxi, 710038

  • Henan Cancer Hospital-henan cancer hospital ( Site 0015)

    Zhengzhou, Henan, 450000

Other trials in China

About this study

Official title: A Phase 3 Study of Pembrolizumab (MK-3475) Versus Chemotherapy in Chinese Participants With Stage IV Microsatellite Instability-High (MSI-H) or Mismatch Repair Deficient (dMMR) Colorectal Cancer (MK-3475-C66)

In this study, Chinese participants with MSI-H or dMMR advanced colorectal cancer will be assigned to receive either pembrolizumab or the Investigator's choice of 1 of 6 standard of care (SOC) chemotherapy regimens for treatment. There is no hypothesis testing for this study.

Keywords
Programmed Cell Death-1 (PD1, PD-1), Programmed Cell Death 1 Ligand 1 (PDL1, PD-L1), Programmed Cell Death 1 Ligand 2 (PDL2, PD-L2)
Medical subject headings
Colorectal Neoplasms, Parkinson Disease 4, Autosomal Dominant Lewy Body

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • PembrolizumabBiological

    Also called KEYTRUDA®, MK-3475

    Intravenous (IV) infusion

  • OxaliplatinDrug

    85 mg/m^2 given as an intravenous infusion (IV) on Day 1 in each 14-day cycle (Q2W) as part of the mFOLFOX6 regimen

  • LeucovorinDrug

    400 mg/m^2 given as an IV on Day 1 Q2W as part of the mFOLFOX6 and FOLFIRI regimens

  • 5-fluorouracilDrug

    Also called 5-FU

    400 mg/m^2 given as an IV bolus on Day 1 and then 1200 mg/m^2/day IV over 2 days for a total dose of 2400 mg/m^2 Q2W as part of the mFOLFOX6 and FOLFIRI regimens

  • IrinotecanDrug

    180 mg/m^2 IV on Day 1 Q2W as part of the FOLFIRI regimen

  • BevacizumabBiological

    IV infusion

  • CetuximabBiological

    IV infusion

Study groups in NCT05239741
Study groupRoleWhat they receive
PembrolizumabExperimentalParticipants receive pembrolizumab 200 mg intravenously (IV) on Day 1 of each 21-day cycle (Q3W) for up to 35 treatments (approximately 2 years).
Receives: Biological: Pembrolizumab
Standard of Care ChemotherapyActive comparatorParticipants receive 1 of 6 possible standard chemotherapy regimens at the discretion of the investigator: (1) mFOLFOX6; (2) mFOLFOX6+bevacizumab 5 mg/kg IV on Day 1 of each 14-day cycle (Q2W); (3) mFOLFOX6+cetuximab 400 mg/m^2 IV over 2 hours then 250 mg/m^2 over 1 hour weekly Q2W; (4) FOLFIRI; (5) FOLFIRI+bevacizumab 5 mg/kg IV on Day 1 Q2W; OR (6) FOLFIRI+cetuximab 400 mg/m^2 IV over 2 hours then 250 mg/m^2 over 1 hour weekly Q2W. Participants with documented disease progression following chemotherapy can receive pembrolizumab 200 mg intravenously (IV) on Day 1 of each 21-day cycle (Q3W) for up to 35 treatments (approximately 2 years).
Receives: Drug: Oxaliplatin; Drug: Leucovorin; Drug: 5-fluorouracil; Drug: Irinotecan; Biological: Bevacizumab; Biological: Cetuximab

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Progression-Free Survival (PFS) per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review (BICR) For All Participants

    PFS is defined as the time from randomization to the first documented disease progression (PD) per RECIST 1.1 or death due to any cause, whichever occurs first. Per RECIST 1.1, PD is defined as ≥20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of ≥5 mm. Note: The appearance of one or more lesions and the unequivocal progression of non-target lesions is also considered PD. The PFS per RECIST 1.1 as assessed by BICR will be reported for all participants.

    Measured: Up to approximately 77 months

  2. Progression-Free Survival (PFS) per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review (BICR) For RAS Wild-type Participants

    PFS is defined as the time from randomization to the first documented disease progression (PD) per RECIST 1.1 or death due to any cause, whichever occurs first. Per RECIST 1.1, PD is defined as ≥20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of ≥5 mm. Note: The appearance of one or more lesions and the unequivocal progression of non-target lesions is also considered PD. The PFS per RECIST 1.1 as assessed by BICR will be reported for RAS wild-type participants .

    Measured: Up to approximately 77 months

Secondary outcomes (6)

  1. Overall Survival (OS) For All Participants

    OS is defined as the time from randomization to death due to any cause. The OS will be reported for all participants.

    Measured: Up to approximately 77 months

  2. Overall Survival (OS) For RAS Wild-type Participants

    OS is defined as the time from randomization to death due to any cause. The OS will be reported for RAS wild-type participants.

    Measured: Up to approximately 77 months

  3. 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) For All Participants

    ORR is defined as the percentage of participants who have a best response of confirmed Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: at least a 30% decrease in the sum of diameters of target lesions) per RECIST 1.1. The percentage for all participants who experience CR or PR as assessed by BICR will be presented.

    Measured: Up to approximately 77 months

  4. 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) For RAS Wild-type Participants

    ORR is defined as the percentage of participants who have a best response of confirmed Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: at least a 30% decrease in the sum of diameters of target lesions) per RECIST 1.1. The percentage for RAS wild-type participants who experience CR or PR as assessed by BICR will be presented.

    Measured: Up to approximately 77 months

  5. Number of Participants Who Experience at Least One Adverse Event (AE)

    An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The number of participants who experience an AE will be reported.

    Measured: Up to approximately 77 months

  6. Number of Participants Who Discontinue Study Treatment Due to an Adverse Event (AE)

    An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The number of participants who discontinue study treatment due to an AE will be reported.

    Measured: Up to approximately 77 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted15 Feb 2022
  2. Study start2 Apr 2022
  3. Primary completion19 Sep 2028 (estimated)
  4. Study completion19 Sep 2028 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 3
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
None (open label)
Enrolment
100 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05239741
Sponsor's protocol ID
3475-C66
Other IDs
MK-3475-C66
Status last verified
May 2026
First submitted
4 Feb 2022
Last updated
22 May 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing Pembrolizumab, Oxaliplatin and Leucovorin in people with Colorectal Neoplasms, run by Merck Sharp & Dohme LLC at 32 sites in China.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 11 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 22 May 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 32 sites in China. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Progression-Free Survival (PFS) per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review (BICR) For All Participants (time frame: Up to approximately 77 months). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05239741.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 May 2026.

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