Symbiotic-GU-06: A Study to Learn About PF-08634404 Alone or In Combination With Enfortumab Vedotin in Urothelial Cancer

Pfizer

Status and phase: Enrolling; Phase 2; Phase 1

Conditions: Urothelial Carcinoma; Urothelial Cancer; Advanced/Metastatic Urothelial Cancer

Treatments: Biological: Enfortumab Vedotin; Biological: PF-08634404

Study type: Interventional

Funder types: Industry

Identifiers

NCT07421700

Symbiotic-GU-06 (Other Identifier)

C6461006

2025-523523-21-00 (Registry Identifier)

Details and patient eligibility

About

This study is being done to learn more about a new medicine called PF-08634404. It is for adults with a type of bladder cancer called locally advanced or metastatic urothelial cancer (LA/mUC), meaning the cancer has spread to nearby tissues or other parts of the body.

The purpose of the study is to see if PF-08634404 is safe, how well it works, how it moves through the body, and how it affects the cancer. The study will also look at how the medicine may change certain markers in the body that are linked to cancer.

To join the study, participants must:

• Be adults (18 years or older) and
• Have locally advanced or metastatic urothelial cancer,

The study has two groups:

• Cohort A: People who have already received treatment for their cancer will get the study medicine ( PF-08634404) alone.
• Cohort B: People who have not had treatment before will get the study medicine along with another cancer medicine called enfortumab vedotin.

Everyone in the study will get the study medicine through a vein (IV infusion) with or without enfortumab vedotin. Treatment will continue as long as it helps and side effects are manageable.

Before starting, participants will go through a screening period to check if they are eligible. During the study, they will have regular visits for treatment, health checks, and tests to see how the cancer is responding. Scans will be done regularly to monitor the cancer.

If the cancer gets worse but the treatment is still helping and side effects are manageable, participants may be allowed to continue treatment with their doctor's and the sponsor's agreement.

Enrollment: 132 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Age ≥18 years at the time of screening.
• Histologically confirmed locally advanced or metastatic urothelial carcinoma (LA/mUC).
• Measurable disease per RECIST v1.1 criteria.
• ECOG performance status of 0 or 1.
• Adequate organ function, including hematologic, hepatic, and renal parameters.
• Willingness to comply with study procedures and provide informed consent.
• For participants of childbearing potential: agreement to use effective contraception during the study and for a defined period after the last dose.

Exclusion criteria

Participants will be excluded if they meet any of the following:

• History of another malignancy within 3 years before the first dose of study intervention, or any evidence of residual disease from a previously diagnosed malignancy
• Known active CNS lesions, including leptomeningeal metastasis, brainstem, meningeal, or spinal cord metastases or compression
• Active autoimmune diseases requiring systemic treatment within the past 2 years
• Participation in another investigational study within 30 days or 5 half-lives of the investigational product.
• Pregnant or breastfeeding individuals.
• Inability or unwillingness to comply with study requirements.
• Study staff or their immediate family members directly involved in the conduct of the study.

Trial design

Primary purpose: Treatment

Allocation: Non-Randomized

Interventional model: Sequential Assignment

Masking: None (Open label)

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132 participants in 2 patient groups

Cohort A

Experimental group

Description:

Participants with previously treated LA/mUC will receive PF-08634404 administered intravenously as monotherapy.

Treatment:

Biological: PF-08634404

Cohort B

Experimental group

Description:

Participants with untreated LA/mUC will receive PF-08634404 in combination with enfortumab vedotin

Treatment:

Biological: PF-08634404

Biological: Enfortumab Vedotin