Symbiotic-GI-13: A Study to Learn About Study Medicine Called PF-08634404 as a Single Treatment and Combination Treatment in Adult Participants With a Liver Cancer Called Hepatocellular Carcinoma, That is Too Advanced to be Removed by Surgery and May Have Spread to Other Parts of the Body.

April 17, 2026 updated by: Pfizer

AN INTERVENTIONAL OPEN-LABEL PHASE 1B/2 STUDY TO EVALUATE SAFETY, PHARMACOKINETICS, AND PRELIMINARY EFFICACY OF PF-08634404 AS MONOTHERAPY AND COMBINATION THERAPY IN ADULT PARTICIPANTS WITH UNRESECTABLE LOCALLY ADVANCED OR METASTATIC HEPATOCELLULAR CARCINOMA

The purpose of this study is to learn about the effects of study medicine (PF-08634404) when given alone or with another antibody (ipilimumab) for the treatment of a type of liver cancer called hepatocellular carcinoma (HCC) that is either locally advanced (spread to nearby tissues) or has spread to other parts of the body.

To join the study, participants must meet the following conditions:

  • Be 18 years or older.
  • Have locally advanced or metastatic HCC.
  • Is not a candidate for complete surgical or loco-regional therapies.
  • Have not received any whole-body treatment for HCC.

Participants will receive PF-08634404 either alone or in combination with ipilimumab. The medicine will be given through intravenous (IV) infusions, which means it will be administered directly into a vein. All treatments will take place at clinical trial sites, where trained medical staff will monitor participants during and after each visit.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

138

Phase

  • Phase 2
  • 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 Contact

Study Locations

  • Japan
      • Fukuoka, Japan, 811-1395
        • Recruiting
        • National Hospital Organization Kyushu Cancer Center
    • Aichi-ken
      • Nagoya, Aichi-ken, Japan, 464-8681
        • Not yet recruiting
        • Aichi Cancer Center
    • Osaka
      • Sakai, Osaka, Japan, 590-0197
        • Recruiting
        • Kindai University Hospital- Osaka Medical Campus
  • Puerto Rico
      • Rio Piedras, Puerto Rico, 00935
        • Recruiting
        • Pan American Center for Oncology Trials, LLC
      • San Juan, Puerto Rico, 00909
        • Recruiting
        • Pan American Center for Oncology Trials, LLC
    • United States of America
      • Dorado, United States of America, Puerto Rico, 00646
        • Recruiting
        • Pan American Center for Oncology Trials, LLC - Dorado Office
      • Mayagüez, United States of America, Puerto Rico, 00680
        • Recruiting
        • Pan American Center for Oncology Trials, LLC - Mayaguez Office
  • Taiwan
      • Taipei, Taiwan, 112
        • Not yet recruiting
        • Taipei Veterans General Hospital
  • United States
    • Nevada
      • Reno, Nevada, United States, 89502
        • Recruiting
        • Renown Regional Medical Center
      • Reno, Nevada, United States, 89502
        • Recruiting
        • Renown Health Medical Oncology
      • Reno, Nevada, United States, 89502
        • Recruiting
        • Renown Office of Clinical Research

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • 18 years of age or older at screening.
  • Locally advanced or metastatic HCC with diagnosis confirmed by histology/cytology or clinically by AASLD criteria (for patients with cirrhosis). Participants without cirrhosis require histological confirmation of diagnosis.
  • Disease that is not amenable to curative surgical and/or locoregional therapies, or progressive disease after surgical and/or locoregional therapies.
  • At least 1 measurable (as defined by RECIST 1.1 per investigator) and untreated lesion.
  • Adequate hepatic, liver, and renal function
  • No prior systemic therapy for HCC.
  • ECOG performance status 0 or 1
  • Child-Pugh Class A

Key Exclusion Criteria:

  • Moderate or severe ascites.
  • History of hepatic encephalopathy.
  • Participants with known active CNS lesions, including leptomeningeal metastasis, brainstem, meningeal, or spinal cord metastases or compression.
  • Clinically significant risk of hemorrhage or fistula.
  • Participants with any history of another malignancy within 3 years.
  • History of allogeneic organ transplantation and allogeneic hematopoietic stem cell transplantation.
  • Participants with active autoimmune diseases requiring systemic treatment within the past 2 years.
  • Clinically significant cardiovascular disease within 6 months prior to the first dose.
  • Major surgery or severe trauma within 4 weeks prior to the first dose or planned major surgery during the study.
  • History of severe bleeding tendency or coagulation dysfunction.
  • History of severe ulcers, unhealed wounds, gastrointestinal perforation, abdominal fistula, gastrointestinal obstruction, intra-abdominal abscess, or acute gastrointestinal bleeding, including bleeding event due to esophageal and/or gastric varices, within 6 months prior to the first dose.
  • Participants with acute, chronic or symptomatic infections.
  • Participants with history of immunodeficiency.

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: Randomized
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Phase 1b
Participants will be allocated to sequential dose levels of PF-08634404 and ipilimumab.
Biological: PF-08634404
Solution for infusion
Biological: Ipilimumab
Solution for infusion
Other Names:
  • YERVOY
Experimental: Phase 2
Participants will be randomized to receive either PF-08634404 monotherapy or PF-08634404 combined with ipilimumab.
Biological: PF-08634404
Solution for infusion
Biological: Ipilimumab
Solution for infusion
Other Names:
  • YERVOY

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of Participants With Adverse Events
Time Frame: Through end of study and up to approximately 24 months
Adverse Events as characterized by type, frequency, severity (as graded by NCI CTCAE version 5.0), timing, seriousness, and relationship to study intervention.
Through end of study and up to approximately 24 months
Phase 1b: Number of participants with Dose limiting toxicities (DLT)
Time Frame: Through 90 days after the last dose of study intervention; Approximately 24 months
DLTs are a predefined set of adverse events that are at least possibly related to any or all of the study interventions. The number of participants who experienced DLTs during the DLT observation period.
Through 90 days after the last dose of study intervention; Approximately 24 months
Phase 2: Confirmed Overall Response Rate (ORR) using RECIST 1.1 as assessed by investigator
Time Frame: Approximately 24 months
ORR is the proportion of participants with a best overall response (BOR) of confirmed CR or confirmed PR per RECIST 1.1 by investigator.
Approximately 24 months
Phase 2: Recommended dose of PF-08634404 in combination with ipilimumab
Time Frame: Approximately 24 months
The doses of PF-08634404 and ipilimumab selected to be used in combination based on safety, tolerability, pharmacokinetics, and initial anti-tumor efficacy from Phase 2.
Approximately 24 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Phase 1b: Confirmed Objective Response Rate (ORR) using RECIST 1.1 as assessed by investigator
Time Frame: Approximately 24 months
ORR is the proportion of participants with a best overall response of confirmed Complete Response (CR) or confirmed Partial Response (PR) per RECIST 1.1 by investigator.
Approximately 24 months
Duration of Response (DOR) per RECIST 1.1 by investigator
Time Frame: Approximately 24 months
DOR is the time from the first documentation of objective response (CR or PR that is subsequently confirmed) to the date of first documented disease progression per RECIST 1.1 as assessed by investigator, or death due to any cause, whichever occurs first.
Approximately 24 months
Progression Free Survival (PFS) per RECIST 1.1 by investigator
Time Frame: Approximately 24 months
PFS is defined as the time from the date of first dose to the date of first documented disease progression per RECIST 1.1 as assessed by investigator, or death due to any cause, whichever occurs first.
Approximately 24 months
Overall Survival (OS)
Time Frame: Approximately 24 months
OS is defined as the time from the date of first dose to the date of death due to any cause.
Approximately 24 months
Number of Participants With Clinical Laboratory Abnormalities
Time Frame: Time from the date of first dose of study intervention through 30-37 days after last dose of study intervention (assessed up to approximately 24 months)
Laboratory abnormalities as characterized by type, frequency, severity (as graded by NCI CTCAE version 5.0), and timing
Time from the date of first dose of study intervention through 30-37 days after last dose of study intervention (assessed up to approximately 24 months)
Pharmacokinetics (PK): Serum concentrations of PF-08634404
Time Frame: Up to 24 months
Predose and/or postdose concentrations of PF-08634404 in combination with ipilimumab.
Up to 24 months
Incidence of antidrug antibody against PF-08634404
Time Frame: Up to 24 months
To evaluate immunogenicity of PF-08634404 in combination with ipilimumab.
Up to 24 months

Collaborators and Investigators

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

Sponsor

Pfizer

Investigators

  • Study Director: Pfizer CT.gov Call Center, Pfizer

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)

December 1, 2025

Primary Completion (Estimated)

October 18, 2027

Study Completion (Estimated)

October 17, 2028

Study Registration Dates

First Submitted

November 7, 2025

First Submitted That Met QC Criteria

November 7, 2025

First Posted (Actual)

November 12, 2025

Study Record Updates

Last Update Posted (Actual)

April 20, 2026

Last Update Submitted That Met QC Criteria

April 17, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • C6461013
  • 2025-523525-17-00 (Ctis)
  • Symbiotic-GI-13 (Other Identifier: Pfizer)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.

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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