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RecruitingLast updated: 19 May 2026

Symbiotic-GI-03: Testing whether a new medicine when given with chemotherapy works better than other standard treatments for people with metastatic bowel cancerAN INTERVENTIONAL, PHASE 3, DOUBLE-BLIND, RANDOMIZED STUDY TO EVALUATE THE EFFICACY AND SAFETY OF PF-08634404 IN COMBINATION WITH CHEMOTHERAPY VERSUS BEVACIZUMAB IN COMBINATION WITH CHEMOTHERAPY IN TREATMENT-NAÏVE PARTICIPANTS WITH METASTATIC COLORECTAL CANCER

Trial purpose

Medical clipboardCancer treatment

Tumor type

Bowel Cancers Lower gastrointestinal tract

Age

People18+

Trial acronym

Symbiotic-GI-03

Clinical summary

Summary

The purpose of this study is to learn more about a new medicine called PF-08634404, and how well it works in people with cancer of the colon or rectum (CRC). The goal is to understand if the new study medicine, combined with chemotherapy that is approved for colorectal cancer, can help people whose cancer has spread or returned after treatments taken before.

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

  • Be 18 years or older.
  • Have colorectal cancer that has spread to other parts of your body (metastatic).
  • Be in good enough health to receive study treatment.
  • Should not be pregnant before starting treatment.

Participants will be randomised (by chance, like flipping a coin) to one of two different treatment arms.

  • Arm A: includes the new medicine PF-08634404 in combination with chemotherapy
  • Arm B: includes an approved medicine for colorectal cancer, called bevacizumab, in combination with chemotherapy.

Participants and their doctors will not know which arm they are being assigned to. Participants will receive all the study medications through intravenous (IV) infusion, which means the medicine is given directly into a vein. The treatment will be given in cycles, and participants may continue receiving it if it is helping and they are not experiencing serious side effects.

The medication will be given at a clinical site, where trained medical staff will check participants during and after each treatment.

  • The study is expected to last approximately 33 months for each participant.
  • Participants will have regular visits to the study site for treatment, health checks, and tests.
  • After stopping treatment, participants will return for a final visit about 30 to 37 days later to check their health and review any side effects.
  • Follow-up will continue every 12 weeks by phone or in person, or by reviewing health records to check on health status and any new treatments.

Conditions

This trial is treating people with stage IV metastatic bowel cancer who have not had prior systemic treatment for their metastatic disease

Eligibility

Inclusion

  • Histological or cytological confirmed colorectal adenocarcinoma.
  • Evidence of Stage IV metastatic disease.
  • No prior systemic therapy for metastatic disease.
  • Eastern Cooperative Oncology Group performance status (ECOG) 0-1
  • At least one measurable lesion according to RECIST 1.1 per Investigator assessment.
  • Adequate hepatic, liver, and renal function

Exclusion

Participants are excluded from the study if any of the following criteria apply:

  • Locally confirmed BRAF V600E mutation
  • Locally confirmed microsatellite instability (MSI)-high or DNA mismatch repair deficiency (dMMR) colorectal cancer
  • Participants with known active symptomatic CNS lesions, including leptomeningeal metastasis, brainstem, meningeal, or spinal cord metastases or compression
  • Clinically significant risk of hemorrhage or fistula
  • Major surgery or severe trauma within 4 weeks prior to the first dose, or planned major surgery during the study
  • History of allogeneic organ transplantation and allogeneic hematopoietic stem cell transplantation
  • Any Grade ≥3 bleeding/hemorrhage events within 28 days of Cycle 1 Day 1, or prior history of clinically significant bleeding events
  • Clinically significant cardiovascular disease, or other comorbidities, within 6 months prior to first dose
  • Participants with active autoimmune diseases requiring systemic treatment within the past 2 years
  • Evidence of non-infectious or drug-induced interstitial lung disease (ILD) pneumonitis

Inclusion

  • Your cancer has spread to other parts of the body (metastatic) or has grown into nearby parts of the body (locally advanced).

Exclusion

  • You have certain types of non-cancer medical conditions.
  • You have had certain treatments, surgical procedures or drugs.
Message

Clinical trials have complex eligibility criteria, and other criteria may apply for this trial. Ask your doctor about whether this trial could be right for you.

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Recruiting hospitals

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More information

Trial Identifiers

Information on this page is partially produced from ClinicalTrials.gov, EU Clinical Trials Register *. View further details about this trial on the registry via the links below:

Trial sponsor

Pfizer

Scientific Title

AN INTERVENTIONAL, PHASE 3, DOUBLE-BLIND, RANDOMIZED STUDY TO EVALUATE THE EFFICACY AND SAFETY OF PF-08634404 IN COMBINATION WITH CHEMOTHERAPY VERSUS BEVACIZUMAB IN COMBINATION WITH CHEMOTHERAPY IN TREATMENT-NAÏVE PARTICIPANTS WITH METASTATIC COLORECTAL CANCER

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