A Phase 1/2 interventional study of Pembrolizumab and I-DXd in Esophageal Squamous Cell Carcinoma, sponsored by Merck Sharp & Dohme LLC. Recruiting at 52 sites in 16 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-27.
Sponsored by Merck Sharp & Dohme LLC (part of Merck & Co., Inc) · Phase 1/2, Interventional, and Treatment
Researchers are looking for new ways to treat esophageal squamous cell carcinoma (ESCC). ESCC is a type of cancer that starts in certain cells that line the esophagus. The esophagus is the tube that connects the throat to the stomach. This study will look at ESCC that is either locally advanced unresectable, which means it has spread into tissue near where it started and cannot be completely removed by surgery, or metastatic, which means it has spread to other body parts.
Available treatments for these types of ESCC include pembrolizumab and chemotherapy. Pembrolizumab is an immunotherapy, which is a treatment that helps the immune system fight cancer. Chemotherapy is medicine that destroys cancer cells or stops them from growing.
Researchers want to learn about giving pembrolizumab and investigational agents, with or without chemotherapy to treat ESCC. Ifinatamab deruxtecan (I-DXd), is an antibody-drug conjugate (ADC). An ADC attaches to a protein on cancer cells and delivers treatment to destroy those cells.
The main goal of this study is to learn about the safety of investigational agents and pembrolizumab with or without chemotherapy and if people tolerate them. Researchers also want to learn how cancer responds (gets smaller or goes away) to the study treatments.
The master protocol is MK-3475-U06.
675 studies on the registry are indexed under Esophageal Squamous Cell Carcinoma; 267 are open to participants now.
This study's planned enrollment of 298 is above the median of 64 across 563 interventional studies indexed under Esophageal Squamous Cell Carcinoma.
Browse Esophageal Squamous Cell Carcinoma studies →Merck Sharp & Dohme LLC is the lead sponsor of 2,166 studies on the registry; 132 are open to participants now.
Of its 501 completed or terminated interventional studies of FDA-regulated products, 370 (74%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
The main inclusion criteria include but are not limited to the following:
Exclusion Criteria
The main exclusion criteria include but are not limited to the following:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.
The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.
The standard rules for measuring tumours on CT or MRI scans, to tell whether a cancer is shrinking, stable or growing during treatment.
“Measurable disease per RECIST 1.1” usually means at least one tumour 10 mm or more at its longest on a CT scan, or a lymph node 15 mm or more across its short axis.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
PD-1, PD-L1 and CTLA-4 are proteins that act as brakes on the immune system. Checkpoint inhibitors, such as pembrolizumab or nivolumab, block them so the immune system can attack a cancer.
PD-L1 can also be measured in a tumour sample. Some scores count stained tumour cells only (TPS); others also count certain immune cells (CPS). The study names the score and the minimum it uses.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Line of therapy
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Measurable disease
The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.
The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
RECIST
The standard rules for measuring tumours on CT or MRI scans, to tell whether a cancer is shrinking, stable or growing during treatment.
“Measurable disease per RECIST 1.1” usually means at least one tumour 10 mm or more at its longest on a CT scan, or a lymph node 15 mm or more across its short axis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
PD-1, PD-L1 and checkpoint inhibitors
PD-1, PD-L1 and CTLA-4 are proteins that act as brakes on the immune system. Checkpoint inhibitors, such as pembrolizumab or nivolumab, block them so the immune system can attack a cancer.
PD-L1 can also be measured in a tumour sample. Some scores count stained tumour cells only (TPS); others also count certain immune cells (CPS). The study names the score and the minimum it uses.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Live vaccines
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
NYHA class (heart failure)
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will receive 400 mg of pembrolizumab via intravenous (IV) infusion every six weeks (Q6W) on Day 1 of each 42-day cycle up to 18 cycles (up to approximately 2 years), and mFOLFOX6 chemotherapy: oxaliplatin 85 mg/m\^2 via IV infusion every 2 weeks (Q2W), until progressive disease (PD) or toxicity; leucovorin 400 mg/m\^2 OR levoleucovorin 200 mg/m\^2 via IV infusion Q2W, until PD or toxicity; 5-fluorouracil (5-FU) 400 mg/m\^2 bolus IV infusion followed by 2400 mg/m\^2 continuous 46-48 hour IV infusion Q2W, until PD or toxicity.
Biological: Pembrolizumab · Drug: Leucovorin · Drug: Levoleucovorin · Drug: 5-Fluorouracil (5-FU) · Drug: Oxaliplatin
Participants will receive 200 mg of pembrolizumab via IV infusion Q3W on Day 1 of each 21-day cycle for up to 35 cycles (up to approximately 2 years). Participants will also receive up to 12 mg/kg I-XDd Q3W via IV infusion, until PD or toxicity.
Biological: Pembrolizumab · Biological: I-DXd · Drug: Rescue Medication
Participants will receive 200 mg pembrolizumab via IV infusion Q3W on Day 1 of each 21-day cycle up to 35 cycles (up to approximately 2 years). Participants will also receive I-DXd up to 12 mg/kg via IV infusion Q3W, until PD or toxicity; 5-FU 400 mg/m\^2 bolus IV infusion followed by 2400 mg/m\^2 continuous 46-48 hour IV infusion Q2W, OR 2400 mg/m\^2 continuous 46-48 hour IV infusion Q2W, until PD or toxicity; and leucovorin 400 mg/m\^2 OR levoleucovorin 200 mg/m\^2 via IV infusion Q2W, until PD or toxicity.
Biological: Pembrolizumab · Biological: I-DXd · Drug: Leucovorin · Drug: Levoleucovorin · Drug: 5-Fluorouracil (5-FU) · Drug: Rescue Medication
Participants will receive 200 mg of pembrolizumab via IV infusion Q3W on Day 1 of each 21-day cycle up to 35 cycles (up to approximately 2 years). Participants will also receive up to 12 mg/kg I-DXd via IV infusion q3w, until PD or toxicity; 5-FU 2400 mg/m\^2 continuous 46-48 hour IV infusion Q2W, until PD or toxicity; 60mg/m\^2 oxaliplatin via IV infusion Q2W, until PD or toxicity; and leucovorin 400 mg/m\^2 OR levoleucovorin 200 mg/m\^2 via IV infusion Q2W, until PD or toxicity.
Biological: Pembrolizumab · Biological: I-DXd · Drug: Leucovorin · Drug: Levoleucovorin · Drug: 5-Fluorouracil (5-FU) · Drug: Oxaliplatin · Drug: Rescue Medication
Participants will receive 400 mg pembrolizumab via IV infusion Q6W on Day 1 of each 42-day cycle up to 18 cycles (up to approximately 2 years). Participants will also receive sacituzumab tirumotecan 4 mg/kg via IV infusion Days 1, 15, and 29 every 42-day cycle, until PD or toxicity; 5-FU 400 mg/m\^2 bolus IV infusion followed by 2400 mg/m\^2 continuous 46-48 hour IV infusion Q2W, OR 2400 mg/m\^2 continuous 46-48 hour IV infusion Q2W, until PD or toxicity; and leucovorin 400 mg/m\^2 OR levoleucovorin 200 mg/m\^2 via IV infusion Q2W, until PD or toxicity.
Biological: Pembrolizumab · Drug: Leucovorin · Drug: Levoleucovorin · Drug: 5-Fluorouracil (5-FU) · Biological: Sacituzumab tirumotecan · Drug: Rescue Medication
IV infusion
Also known as: MK-3475, KEYTRUDA®
IV infusion
Also known as: Ifinatamab deruxtecan, MK-2400, DS-7300a
IV infusion
IV infusion
IV Infusion
IV infusion
IV infusion
Also known as: MK-2870, SKB264
Includes 5-HT3 receptor antagonist, NK-1 receptor antagonist, and corticosteroid for Arms 2, 3, and 4, and H1 receptor antagonist, H2 receptor antagonist, acetaminophen, dexamethasone, and steroid mouthwash for Arm 5, administered per approved product label
Percentage of Participants who Experience Dose Limiting Toxicities (DLTs) During the Safety Lead-In Phase
Percentage of participants experiencing toxicities that are possibly, probably, or definitely related to study intervention; that meet pre-defined severity criteria; and result in a change in the given dose.
Time frame: Up to approximately 28 days
Percentage of Participants who Experience 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. The percentage of participants who experience an AE will be reported.
Time frame: Up to approximately 77 months
Objective Response Rate (ORR)
ORR is defined as a confirmed complete response (CR: the disappearance of all target lesions) or partial response (PR: at least a 30% decrease in the sum of diameters of target lesions) per Response Evaluation Criteria In Solid Tumors (RECIST) 1.1 as assessed by blinded independent central review (BICR). The percentage of participants who experience CR or PR as assessed by BICR will be presented.
Time frame: Up to approximately 77 months
Duration of Response (DOR)
For participants who demonstrate a 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, DOR is defined as the time from first documented evidence of CR or PR until PD or death. Per RECIST 1.1, PD is defined as at least a 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 at least 5 mm. The appearance of one or more new lesions is also considered PD. DOR as assessed by BICR will be presented.
Time frame: Up to approximately 77 months
Progression-Free Survival (PFS)
PFS is defined as the time from randomization to the first documented progressive disease (PD) or death from any cause, whichever occurs first. Per RECIST 1.1, PD is defined as at least a 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 at least 5 mm. The appearance of one or more new lesions is also considered PD. PFS as assessed by BICR will be presented.
Time frame: Up to approximately 77 months
Overall Survival (OS)
OS is defined as the time from allocation/randomization to death due to any cause.
Time frame: Up to approximately 77 months
Disease Control Rate (DCR)
DCR is defined as a confirmed complete response (CR) or partial response (PR), or stable disease (SD) with at least 6 months PFS per RECIST 1.1 as assessed by BICR.
Time frame: Up to approximately 77 months
Maximum Plasma Concentration (Cmax) of I-DXd
Cmax is defined as the peak level I-DXd reaches in the blood plasma. Blood samples collected predose and at multiple timepoints postdose will be used to determine the Cmax of I-DXd when co-administered with other investigational agents.
Time frame: At designated time points up to approximately 65 months
Time to Maximum Plasma Concentration (Tmax) of I-DXd
Tmax is defined as the time it took I-DXd to reach its peak level in blood plasma. Blood samples collected predose and at designated timepoints postdose will be used to determine the Tmax of I-DXd when co-administered with other investigational agents.
Time frame: At designated time points up to approximately 65 months
Area Under the Concentration-Time Curve from Time 0 to Last Measurable Plasma Concentration (AUClast) of I-DXd
AUClast is defined as the area under the concentration-time curve from time 0 to the last measurable concentration of I-DXd in the blood plasma. Blood samples collected at predose and at designated timepoints postdose will be used to determine the AUClast of I-DXd in combination with other agents.
Time frame: At designated time points up to approximately 65 months
Area Under the Concentration-Time Curve from Time 0 to the End of the Dosing Period (AUCtau) of I-DXd
AUCtau is defined as the area under the concentration-time curve from time zero to the end of the dosing period. Blood samples collected at predose and at designated timepoints postdose will be used to determine the AUCtau of I-DXd in combination with other agents.
Time frame: At designated time points up to approximately 65 months
The Percentage of Participants with Antidrug Antibodies (ADA) Against I-DXd
Blood samples collected at designated timepoints will be used to determine the ADA response to I-DXd. The percentage of participants with ADA will be reported.
Time frame: Up to approximately 65 months
The Percentage of Participants with Treatment-Emergent ADA Against I-DXd
Blood samples collected at designated timepoints will be used to determine the treatment-emergent ADA response to I-DXd. The percentage of participants who have treatment-emergent I-DXd ADA will be reported.
Time frame: Up to approximately 65 months
Plan to share: Yes — https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
Data sharing details ↗ · externaldatasharing-msd.com
Started Jul 2025 (actual). Primary completion is estimated for Jan 2032, 77 months after the start.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Studies of the drugs tested here: Ifinatamab deruxtecan · Sacituzumab tirumotecan
Esophageal Squamous Cell Carcinoma →