FLX475 Combined With Pembrolizumab in Patients With Advanced or Metastatic Gastric Cancer

September 5, 2025 updated by: Hanmi Pharmaceutical Company Limited

A Phase 2 Study to Assess the Safety, Efficacy of FLX475 Combined With Pembrolizumab in Patients With Advanced or Metastatic Gastric Cancer

This clinical study is a Phase 2, open-label study to assess the efficacy, safety profile of FLX475 combined with pembrolizumab in patients with advanced or metastatic gastric cancer. This study is designed to assess the potential anti-tumor activity when administered at the 100mg QD of FLX475 with pembrolizumab and will be conducted (2) cohorts as detailed below.

  • Cohort 1: EBV negative / CPI naïve gastric cancer subjects who have progressed on at least 2 prior systemic treatments for advanced or metastatic gastric cancer
  • Cohort 2: EBV positive / CPI naïve gastric cancer subjects who had at least 1 prior systemic treatment for advanced or metastatic gastric cancer

Approximately 90 subjects may be enrolled across two cohorts to examine the safety and efficacy.

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.
20

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 2

Contacts and Locations

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

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • South Korea
      • Seoul, South Korea
        • Asan Medical Center
      • Seoul, South Korea
        • Korea University Guro Hospital
      • Seoul, South Korea
        • Samsung Medical Center
      • Seoul, South Korea
        • Seoul National University Hospital
      • Seoul, South Korea
        • Gangnam Severance Hospital
      • Seoul, South Korea
        • Severance Hospital
    • Gyeonggi-do
      • Anyang-si, Gyeonggi-do, South Korea
        • Hanllym University Medical Center
      • Seongnam-si, Gyeonggi-do, South Korea
        • Seoul National University Bundang Hospital
      • Suwon, Gyeonggi-do, South Korea
        • The Catholic University of Korea St. Vincent Hospital
    • Jeollanam-do
      • Hwasun, Jeollanam-do, South Korea
        • Chonnam National University Hwasun Hospital

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:

  • All patients must have histologically or cytologically confirmed, advanced, relapsed or metastatic gastric or gastroesophageal junction adenocarcinoma

  • Patient must have one of the following diagnoses to be eligible for enrollment into cohorts:

    • Cohort 1: Checkpoint inhibitor naïve Epstein-Barr Virus negative (EBV-) gastric cancer patient who has had a disease progression after at least 2 prior systemic treatments for advanced or metastatic gastric cancer
    • Cohort 2: Checkpoint inhibitor naïve Epstein-Barr virus positive (EBV+) gastric cancer patient (as determined by standard methods, e.g. EBER ISH or LMP-1 IHC) who had at least 1 prior systemic treatment for advanced or metastatic gastric cancer
  • Eastern Cooperative Oncology Group (ECOG) Performance Status 0-1
  • Patient must have at least one measurable lesion at baseline by computed tomography(CT) or magnetic resonance imaging (MRI)
  • Tumor available for biopsy

Exclusion Criteria:

  • Prior therapy with an anti-PD-1, anti-PD-L1, or anti-PD-L2 agent or an agent directed to another stimulatory or co-inhibitory T-cell receptor (e.g., CTLA-4, OX-40, CD137), any history of discontinuing from that treatment due to Grade 3 or higher immune-related adverse event (irAE)
  • Patient with MSI-H status
  • Active autoimmune disease or serious autoimmune disease within past 2 years requiring systemic therapy
  • History of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced pneumonitis, idiopathic pneumonitis, (non-infectious) pneumonitis that required steroids, or clinical symptoms of active pneumonitis
  • Significant cardiovascular disease. New York Heart Association (NYHA) Class 3 or 4 congestive heart failure, or chronic Grade 3 hypertension.
  • Significant screening electrocardiogram (ECG) abnormalities
  • Has had an allogenic tissue/solid organ transplant

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: FLX475 and pembrolizumab combination therapy
  • Cohort 1: EBV negative / CPI naïve gastric cancer patient who has had a disease progression after at least 2 prior systemic treatments for advanced or metastatic gastric cancer
  • Cohort 2: EBV positive / CPI naïve gastric cancer patient (as determined by standard methods, e.g. EBER ISH or LMP-1 IHC) who had at least 1 prior systemic treatment for advanced or metastatic gastric cancer
Drug: Pembrolizumab
IV infusion
Other Names:
  • KEYTRUDA®
Drug: FLX475
tablet

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
Overall Response Rate (ORR) in Subjects Treated With FLX475 in Combination With Pembrolizumab
Time Frame: Initial assessment performed after the first 2 cycles, then every 2 cycles for the first year, followed by every 3 cycles thereafter for up to 2 years and at any time per investigator's discretion and at ED/EOT, up to 2 years.
The primary efficacy endpoint is Objective Response Rate (ORR) defined as the proportion of subjects whose confirmed best overall response is either Complete Response (CR) or Partial Response (PR) according to RECIST version 1.1. For the efficacy endpoints (such as ORR and DCR), frequency and percentage of subjects who have achieved a response will be summarized by cohort and 95% 2-sided confidence interval will be calculated by Clopper-Pearson method.
Initial assessment performed after the first 2 cycles, then every 2 cycles for the first year, followed by every 3 cycles thereafter for up to 2 years and at any time per investigator's discretion and at ED/EOT, up to 2 years.

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
Disease Control Rate (DCR) in Subjects Treated With FLX475 in Combination With Pembrolizumab
Time Frame: Initial assessment performed after the first 2 cycles, then every 2 cycles for the first year, followed by every 3 cycles thereafter for up to 2 years and at any time per investigator's discretion and at ED/EOT, up to 2 years.
The Disease Control Rate (DCR) is defined as the proportion of subjects with confirmed best overall response of CR, PR or SD according to RECIST version 1.1.
Initial assessment performed after the first 2 cycles, then every 2 cycles for the first year, followed by every 3 cycles thereafter for up to 2 years and at any time per investigator's discretion and at ED/EOT, up to 2 years.
Time to Response (TTR) in Subjects Treated With FLX475 in Combination With Pembrolizumab
Time Frame: Initial assessment performed after the first 2 cycles, then every 2 cycles for the first year, followed by every 3 cycles thereafter for up to 2 years and at any time per investigator's discretion and at ED/EOT, up to 2 years.
The Time to Response (TTR) is defined as the time from the date of first administration of study treatment to first documented Complete Response (CR) or Partial Response (PR).
Initial assessment performed after the first 2 cycles, then every 2 cycles for the first year, followed by every 3 cycles thereafter for up to 2 years and at any time per investigator's discretion and at ED/EOT, up to 2 years.
Duration of Response (DoR) in Subjects Treated With FLX475 in Combination With Pembrolizumab
Time Frame: Initial assessment performed after the first 2 cycles, then every 2 cycles for the first year, followed by every 3 cycles thereafter for up to 2 years and at any time per investigator's discretion and at ED/EOT, up to 2 years.
The Duration of Response (DoR) is measured from the date of the first observation of tumor response (Complete Response (CR) or Partial Response (PR), whichever occurs first) to the date of disease progression or death for the subject with an objected response.
Initial assessment performed after the first 2 cycles, then every 2 cycles for the first year, followed by every 3 cycles thereafter for up to 2 years and at any time per investigator's discretion and at ED/EOT, up to 2 years.
Progression-free Survival (PFS) in Subjects Treated With FLX475 in Combination With Pembrolizumab
Time Frame: Initial assessment performed after the first 2 cycles, then every 2 cycles for the first year, followed by every 3 cycles thereafter for up to 2 years and at any time per investigator's discretion and at ED/EOT, up to 2 years.
The Progression-free Survival (PFS) is defined as the time from the date of first administration of study treatment to determination of tumor progression by RECIST version 1.1 or death due to any cause, whichever occurs first.
Initial assessment performed after the first 2 cycles, then every 2 cycles for the first year, followed by every 3 cycles thereafter for up to 2 years and at any time per investigator's discretion and at ED/EOT, up to 2 years.
Overall Survival (OS) in Subjects Treated With FLX475 in Combination With Pembrolizumab
Time Frame: From baseline (Cycle 1 Day 1 prior to administration of the first study dose) until death from any cause.
The Overall Survival (OS) is defined as the duration of time from the treatment start date to time to death from any cause. If subjects survive at the time of analysis, the subject will be censored at the last date of survival confirmed.
From baseline (Cycle 1 Day 1 prior to administration of the first study dose) until death from any cause.

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.
Hanmi Pharmaceutical Company Limited

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

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.
May 18, 2021

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.
August 12, 2024

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 12, 2024

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).
February 22, 2021

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.
February 22, 2021

First Posted (Actual)

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.
February 24, 2021

Study Record Updates

Last Update Posted (Estimated)

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.
September 25, 2025

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.
September 5, 2025

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.
September 1, 2025

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.
  • HM-CCRI-201
  • KEYNOTE-B83 (Other Identifier: Merck Sharp & Dohme LLC)
  • MK-3475-B83 (Other Identifier: Merck Sharp & Dohme LLC)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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