A Study to Learn About the Study Medicine Called PF-08634404 in Combination With Chemotherapy in Gastroesophageal Cancer

Pfizer

Status and phase: Enrolling; Phase 3; Phase 2

Conditions: Gastroesophageal Junction Cancer; Untreated Advanced or Metastatic Gastric, Gastroesophageal Junction , or Esophageal Adenocarcinoma; Esophageal Adenocarcinoma; Metastatic Gastric Cancer

Treatments: Biological: Nivolumab; Biological: PF-08634404; Drug: Chemotherapy

Study type: Interventional

Funder types: Industry

Identifiers

NCT07392892

2025-524717-86-00 (Registry Identifier)

C6461016

Details and patient eligibility

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. 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.

Enrollment: 840 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

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

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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840 participants in 3 patient groups

Phase 2 Portion

Experimental group

Description:

PF-08634404 + Chemotherapy

Treatment:

Drug: Chemotherapy

Biological: PF-08634404

Phase 3: Arm A

Experimental group

Description:

PF-08634404 + Chemotherapy

Treatment:

Drug: Chemotherapy

Biological: PF-08634404

Phase 3: Arm B

Active Comparator group

Description:

Nivolumab + Chemotherapy

Treatment:

Drug: Chemotherapy

Biological: Nivolumab