Tests a new medicine with chemotherapy in untreated stomach or esophageal cancer
Tests PF-08634404 with chemotherapy in adults with advanced gastric or esophageal cancer.
Key facts
- Who runs it
- Pfizer
- Where
- London, CanadaSee the siteAlso in 9 other countries, 98 sites
- Trial code
- Registry title
- Symbiotic-GI-16: A Study to Learn About the Study Medicine Called PF-08634404 in Combination With Chemotherapy in Gastroesophageal Cancer
- Status
- Recruiting
- Phase
- Phase 2/3
- People taking part
- 840 people, planned
- Started
- 14 May 2026
- Expected to end
- 21 Jul 2032
- Type of study
- Interventional, 3 groupsOne group gets an existing treatment, for comparison.
- Treatments tested
- PF-08634404
- Chemotherapy
- Nivolumab
- Record updated
- 13 October 2026
Who can take part
AI summary
From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.
The trial is looking for adults with gastric, gastroesophageal junction or esophageal adenocarcinoma that is locally advanced or has spread, who have not yet had treatment for advanced disease.
- Age
- 18 years or older
- Sex
- Men and women
- Disease stage
- Gastric, gastroesophageal junction or esophageal adenocarcinoma, locally advanced or metastatic, confirmed by tissue or cell tests. ECOG performance status 0-1.
- Earlier treatment
- No earlier systemic therapy for advanced or metastatic disease.
- Biomarker or test result
- HER-2 negative and PD-L1 positive, based on local testing.
Main reasons for not taking part
- Known active cancer spread to the brain or spinal cord (CNS metastases)
- Clinically significant risk of bleeding or fistula
- Major surgery or severe trauma within 4 weeks before the first dose
- Past allogeneic organ transplant or allogeneic stem cell transplant
- Active autoimmune disease needing systemic treatment in the past 2 years
The registry criteria, word for word
Show all 15 criteriaShow less
Who can take part
- 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
Who cannot take part
- Major surgery or severe trauma within 4 weeks prior to the first dose, or planned major surgery during the study
- 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
- Clinically significant risk of hemorrhage or fistula
- History of allogeneic organ transplantation and allogeneic hematopoietic stem cell transplantation
- 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
- Participants with known active CNS metastases, including leptomeningeal, brainstem, meningeal, or spinal cord metastases or compression
Where in Canada
Also in 9 other countries, 98 sites
- London Health Sciences Centre - Verspeeten Family Cancer CentreLondon, CanadaNot yet recruiting
About the trial
What the trial wants to find out
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.
Read full original descriptionShow less
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.
The 3 groups in the trial
- Phase 2 PortionTreatment being tested
PF-08634404 + Chemotherapy
Treatment: PF-08634404 and Chemotherapy
- Phase 3: Arm ATreatment being tested
PF-08634404 + Chemotherapy
Treatment: PF-08634404 and Chemotherapy
- Phase 3: Arm BExisting treatment, for comparison
Nivolumab + Chemotherapy
Treatment: Chemotherapy and Nivolumab
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Contact the study team: see the registry record → Contacts and Locations
Print a page for my doctorData and sources
- Registry record
- Listed on ClinicalTrials.gov and on the EU's official list of trials (CTIS).
- Official title
- A PHASE 2/3 INTERVENTIONAL STUDY OF PF-08634404 IN COMBINATION WITH CHEMOTHERAPY IN TREATMENT-NAÏVE PARTICIPANTS WITH LOCALLY ADVANCED OR METASTATIC GASTRIC, GASTROESOPHAGEAL JUNCTION, OR ESOPHAGEAL ADENOCARCINOMA
- Plain-language title
- Tests a new medicine with chemotherapy in untreated stomach or esophageal cancerGenerated from the registry record. The registry title is the official one.
- AI summary
- From the trial's eligibility criteria. Read by machine on 12 November 2026.
- Record updated
- 13 October 2026