Pembrolizumab With Locally Delivered Radiation Therapy for the Treatment of Metastatic Esophageal Cancers

February 24, 2026 updated by: Washington University School of Medicine

A Pilot Study Combining Pembrolizumab With Locally Delivered Radiation Therapy for the Treatment of Metastatic Esophageal Cancers

The investigators propose to treat patients with metastatic esophageal cancers and dysphagia with two fractions of brachytherapy followed by pembrolizumab. The brachytherapy is hypofractionated and will provide a radiation dose of sufficient intensity to induce the release of tumor-derived antigens and trigger an antitumor immune response. The simplicity of the design should maximize the chance to examine the hypothesis that radiotherapy can induce an immune response, which can then be augmented by pembrolizumab treatment. Success in this study would provide the impetus to conduct further trials aimed at developing this unique strategy as a more broadly applicable therapeutic option in the treatment of patients suffering from these deadly cancers, and will provide important mechanistic insights into the relationship between radiation treatment and immune therapy augmentation.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
16

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Missouri
      • St Louis, Missouri, United States, 63110
        • Washington University School of Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Any patient with metastatic esophageal cancer that is deemed a candidate for brachytherapy for local control or treatment of dysphagia as determined by treating physician
  • Presence of an evaluable metastatic lesion (locoregional lymph nodes are acceptable)
  • At least 18 years of age.
  • ECOG performance status 0-2

  • Adequate bone marrow and organ function as defined below:

    • Absolute neutrophil count ≥ 1,500/mcL
    • Platelets ≥ 100,000/mcL
    • Hemoglobin ≥ 9 g/dL
    • Total bilirubin ≤ 1.5 x IULN OR Direct bilirubin ≤ IULN for patients with total bilirubin > 1.5 x IULN
    • AST(SGOT)/ALT(SGPT) ≤ 2.5 x IULN (or ≤ 5 x IULN for patients with liver metastases)
    • Serum creatinine ≤ 1.5 x IULN OR Creatinine clearance by Cockcroft-Gault ≥ 60 mL/min/1.73 m2 for patients with creatinine levels > 1.5 x IULN
    • INR or PT ≤ 1.5 x IULN unless patient is receiving anticoagulant therapy as long as INR or PTT is within therapeutic range of intended use of anticoagulants
    • aPTT ≤ 1.5 x IULN unless patient is receiving anticoagulant therapy as long as INR or PTT is within therapeutic range of intended use of a anticoagulants
  • Sexually active women of childbearing potential and men must agree to use contraceptive methods prior to study entry, for the duration of study participation, and for 120 days after the last dose of pembrolizumab. Should a woman become pregnant or suspect she is pregnant while participating in this study, she must inform her treating physician immediately.
  • Either enrolled in HRPO# 201107221 ("Tissue and Blood Acquisition for Genomic Analysis and Collection of Health Information for Patients with Gastrointestinal Cancers"), which facilitates the collection of specimens for correlative studies, or consenting to collection of blood and tissue as part of this protocol for research testing.
  • Ability to understand and willingness to sign an IRB approved written informed consent document (or that of legally authorized representative, if applicable).

Exclusion Criteria:

  • Prior treatment with an anti-PD-1, anti-PD-L1, or anti-PD-L2 agent
  • Received a live vaccine within 30 days prior to the first dose of pembrolizumab. Examples of live vaccines include, but are not limited to, the following: measles, mumps, rubella, varicella/zoster (chicken pox), yellow fever, rabies, Bacillus Calmette-Guérin (BCG), and typhoid vaccine. Seasonal influenza vaccines for injection are generally killed virus vaccines and are allowed; however, intranasal influenza vaccines (e.g. FluMist) are live attenuated vaccines and are not allowed.
  • 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 pembrolizumab.
  • Currently receiving any other investigational agents, has participated in a study of an investigational agent, or use of an investigational device within 4 weeks of the first dose of pembrolizumab.
  • Has received systemic therapy within 4 weeks of the first dose of pembrolizumab.
  • Known active central nervous system metastases and/or carcinomatous meningitis. Subjects with previously treated brain metastases may participate provided they are stable (without evidence of progression by imaging for at least 4 weeks prior to the first dose of MK-3475 and any neurologic symptoms have returned to baseline), have no evidence of new or enlarging brain metastases, and are not using steroids for at least 7 days prior to trial treatment. This exception does not include carcinomatous meningitis which is excluded regardless of clinical stability.
  • A history of allergic reactions attributed to compounds of similar chemical or biologic composition to pembrolizumab or other agents used in the study.
  • Uncontrolled intercurrent illness that would limit compliance with study requirements. This would include, but is not limited to: ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, immunosuppression, autoimmune conditions, underlying pulmonary disease, or psychiatric illness/social situations.
  • Has an active autoimmune disease requiring systemic treatment within the past 2 years (i.e. with use of disease modifying agents, corticosteroids, or immunosuppressive drugs). Replacement therapy (e.g. thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency, etc.) is not considered a form of systemic treatment.
  • History of (non-infectious) pneumonitis that required steroids or current pneumonitis
  • Pregnant and/or breastfeeding. Women of childbearing potential must have a negative pregnancy test within 72 hours of study entry.
  • Known history of hepatitis B (defined as hepatitis B surface antigen [HBsAg] reactive) or known active hepatitis C virus (defined as HCV RNA [qualitative] is detected).
  • Known history of active TB.
  • Known history of HIV (HIV 1/2 antibodies).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Pembrolizumab and Brachytherapy
  • Brachytherapy dose=16 Gy delivered in 2 fractions of 8 Gy per fraction, separated by 7-10 days between fractions.
  • Pembrolizumab started within 1 week after completion of brachytherapy administered as an intravenous infusion with a dose of 200 mg. It will be given every 3 weeks.
  • Research endoscopic biopsy for 8 consented patients will take place 1-2 weeks after initiation of brachytherapy.
Drug: Pembrolizumab
Provided by Merck.
Other Names:
  • Keytruda
  • MK-3475
Radiation: Brachytherapy
It will be delivered using a high-dose-rate Ir-192 afterloader via a dedicated esophageal applicator.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Safety as Measured by Number of Participants With Grade 3 or Higher Treatment Related Adverse Events
Time Frame: Through 30 days after completion of treatment (median length of adverse event follow-up 106 days, full range 42-1023 days)
The descriptions and grading scales found in the revised NCI Common Terminology Criteria for Adverse Events (CTCAE) version 4.03 will be utilized for all toxicity reporting. In general, CTCAE version 4.03 has the following definitions for the grading scale: Grade 3: severe or medically significant but not immediately life-threatening; hospitalization or prolongation of hospitalization indicated; disabling; limiting self care ADL. Grade 4: life-threatening consequences; urgent intervention indicated. Grade 5: Death related to AE.
Through 30 days after completion of treatment (median length of adverse event follow-up 106 days, full range 42-1023 days)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Mean Percent Change in Esophageal Tumor Length as Measured by Endoscopy
Time Frame: Prior to brachytherapy and once anytime between 2-6 months after start of pembrolizumab (up to approximately 7 months post-baseline)
Prior to brachytherapy and once anytime between 2-6 months after start of pembrolizumab (up to approximately 7 months post-baseline)
Change in Esophageal Lumen Size as Measured by Endoscopy
Time Frame: Prior to brachytherapy, at 1-2 weeks after initiation of brachytherapy (optional), and 2-6 months after start of pembrolizumab
Prior to brachytherapy, at 1-2 weeks after initiation of brachytherapy (optional), and 2-6 months after start of pembrolizumab
Worst Grade of Dysphagia Experienced by Participant
Time Frame: From start of treatment through 8 weeks post-pembrolizumab (median length of dysphagia follow-up 132 days, full range 42-1049 days)
The descriptions and grading scales found in the revised NCI Common Terminology Criteria for Adverse Events (CTCAE) version 4.03 will be utilized for all toxicity reporting. Grade 1: symptomatic, able to eat regular diet; Grade 2: symptomatic and altered eating/swallowing; Grade 3: severely altered eating/swallowing; tube feeding or TPN or hospitalization indicated; Grade 4: life-threatening consequences; urgent intervention indicated; Grade 5: death.
From start of treatment through 8 weeks post-pembrolizumab (median length of dysphagia follow-up 132 days, full range 42-1049 days)
Overall Response as Measured by Immune-Related Response Criteria (irRC)
Time Frame: Through completion of treatment (median length of treatment 76 days, full range 25-993 days)

- Response and progression will be evaluated in this study using Immune-Related Response Criteria.

  • irCR, complete disappearance of all lesions (whether measurable or not, and no new lesions) - confirmation by a repeat, consecutive assessment no less than 4 weeks from the date first documented
  • irPR, decrease in tumor burden ≥ 50% relative to baseline - confirmed by a consecutive assessment at least 4 weeks after first documentation
  • irSD, not meeting criteria for irCR or irPR, in absence of irPD
  • irPD, increase in tumor burden ≥ 25% relative to nadir (minimum recorded tumor burden) - confirmation by a repeat, consecutive assessment no less than 4 weeks from the date first documented
  • Patients are considered to have irPR or irSD even if new lesions are present as long as they meet the respective thresholds of response as described above. Furthermore, patients are not considered to have irPD if new lesions are present and the tumor burden of all lesions.
Through completion of treatment (median length of treatment 76 days, full range 25-993 days)
Median Progression-free Survival (PFS)
Time Frame: Up to 1 year after completion of treatment (median length of treatment 76 days, full range 25-993 days)
PFS was defined as the duration from the first infusion of pembrolizumab until disease progression or death (whichever occurred first).
Up to 1 year after completion of treatment (median length of treatment 76 days, full range 25-993 days)
Median Overall Survival (OS)
Time Frame: Up to 1 year after completion of treatment (median length of treatment 76 days, full range 25-993 days)
OS was defined as the duration from the first infusion of pembrolizumab until death.
Up to 1 year after completion of treatment (median length of treatment 76 days, full range 25-993 days)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Washington University School of Medicine

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Merck Sharp & Dohme LLC

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Cliff Robinson, M.D., Washington University School of Medicine

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 8, 2016

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 24, 2020

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 3, 2021

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 24, 2015

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 24, 2015

First Posted (Estimated)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 30, 2015

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 18, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 24, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 201603087

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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