NCT07392892 · Pfizer
Symbiotic-GI-16: A Study to Learn About the Study Medicine Called PF-08634404 in Combination With Chemotherapy in Gastroesophageal Cancer
What this study is about
This study is being done to learn more about a new medicine called PF-08634404 and how well it works when given with chemotherapy to people with gastroesophageal cancer that is 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.
View original scientific description
This study is being done to learn more about a new medicine called PF-08634404 and how well it works when given with chemotherapy to people with gastroesophageal cancer that is 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 gastric, gastroesophageal junction or esophageal adenocarcinoma Be treatment naïve for advanced or metastatic disease Be in good physical condition and have healthy organs based on medical tests. The study has two parts: * In the first part, researchers will check how safe the study medicine in combination with chemotherapy is and how well people respond to it. * In the second part, they will compare study medicine plus chemotherapy to another approved treatment (nivolumab plus chemotherapy) to see which works better. The treatment will be given in repeated time periods called cycles.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Histological or cytological confirmed gastric, gastroesophageal junction or esophageal adenocarcinoma.
- Evidence of locally advanced or metastatic disease.
- Eastern Cooperative Oncology Group performance status (ECOG) 0-1
- No prior systemic therapy for advanced or metastatic disease.
- Adequate hepatic, liver, and renal function
- HER-2 negative status based on local testing
- PD-L1 positive status based on local testing
Exclusion criteria
- Participants with known active CNS metastases, including leptomeningeal, 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
Where
- Los Angeles, California
- Aurora, Colorado
- Boulder, Colorado
- Centennial, Colorado
- Colorado Springs, Colorado
- Denver, Colorado
- Englewood, Colorado
- Lakewood, Colorado
- Littleton, Colorado
- Lone Tree, Colorado
- Longmont, Colorado
- Pueblo, Colorado
And 42 more locations — see the full list below.
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 12, 2026 · Source of record for eligibility and locations