Recruiting

Phase 2

Phase 3

PF-08634404 with ChemotherapySymbiotic-Lung-04: A Study to Learn About the Study Medicine Called PF-08634404 in Combination With Chemotherapy in Adult Participants With Extensive-Stage Small Cell Lung Cancer

Sponsor:

Pfizer

Code:

NCT07226999

Conditions

Small Cell Lung Cancer (SCLC)

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

PF-08634404

Atezolizumab

Chemotherapy

Study Details

Brief summary:

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 adults with extensive-stage small cell lung cancer (ES-SCLC), a fast-growing type of lung cancer that has spread widely in the body.

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

Be 18 years or older.
Have extensive-stage small cell lung cancer confirmed by lab tests.
Have not received chemotherapy or radiation for this type of lung cancer.
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 is and how well people tolerate it when given with chemotherapy.
In the second part, they will compare study medicine plus chemotherapy to another approved treatment (atezolizumab plus chemotherapy) to see which works better.

Participants will receive the treatment through IV infusions (medicine given directly into a vein). The treatment will be given in repeated time periods called cycles. Some participants will continue receiving the study medicine alone after the initial treatment.

Conditions

Small Cell Lung Cancer (SCLC)

Study ID

NCT07226999

Start date

Dec 9, 2025

Status verified date

Aug, 2026

Completion date

Mar 11, 2034

Anticipated

Primary completion date

Jun 14, 2030

Anticipated

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

Histologically or cytologically confirmed extensive-stage small cell lung cancer (ES-SCLC).
Participants have not received systemic therapy (chemotherapy, radiotherapy, chemoradiation) for ES-SCLC.
Treatment-free for at least 6 months since last chemo/radiotherapy, among those treated (with curative intent) with prior chemo/radiotherapy for limited-stage SCLC
Have at least one measurable lesion as the targeted lesion based on RECIST V1.1.
Eastern Cooperative Oncology Group performance status of 0 or 1.
Adequate organ function

Exclusion Criteria:

known active CNS lesions, including brainstem, meningeal, or spinal cord metastases or compression
Leptomeningeal disease
Clinically significant risk of hemorrhage or fistula
history of another malignancy within 3 years
active autoimmune diseases requiring systemic treatment within the past 2 years

Study Design

Enrollment

550 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Phase 2 Single arm

Participants will receive PF-08634404 in combination with chemotherapy

experimental: Phase 3 Experimental Arm

Participants will receive PF-08634404 in combination with chemotherapy

active comparator: Phase3 Control Arm

Participants will receive atezolizumab in combination with chemotherapy

Interventions

PF-08634404

Concentrate for solution for infusion

Atezolizumab

Injection for intravenous use

Chemotherapy

Injection for intravenous use

Primary outcome measure

Phase 2: Confirmed Objective Response Rate (ORR) per Response Evaluation Criteria in Solid Tumors version 1.1 [RECIST 1.1] based on the investigator's assessment [ Time Frame: Up to approximately 2 years after completion of study treatment of last study participant ]
Phase 2: Number of participants with treatment-emergent adverse events [ Time Frame: Up to 90 days after the last dose of treatment ]
Phase 3: Overall Survival (OS) [ Time Frame: Up to approximately 2 years after completion of study treatment of last study participant ]

Central Contacts and Locations

Central contacts

Pfizer CT.gov Call Center

1-800-718-1021 ClinicalTrials.gov_Inquiries@pfizer.com

Locations

Highlands Oncology Group

Recruiting

Fayetteville, Arkansas, United States, 72703

Highlands Oncology Group

Recruiting

Rogers, Arkansas, United States, 72758

Highlands Oncology Group

Recruiting

Springdale, Arkansas, United States, 72762

BRCR Coral Springs

Recruiting

Coral Springs, Florida, United States, 33065

Mid Florida Hematology and Oncology Center

Recruiting

Orange City, Florida, United States, 32763

BRCR Global - Tamarac

Recruiting

Tamarac, Florida, United States, 33321

Texas Oncology - Gulf Coast

Recruiting

Beaumont, Texas, United States, 77702

Texas Oncology - San Antonio

Recruiting

Fredericksburg, Texas, United States, 78624

Texas Oncology - Gulf Coast

Recruiting

Houston, Texas, United States, 77024

Texas Oncology - Gulf Coast

Recruiting

Houston, Texas, United States, 77054

US Oncology Investigational Product Center (IPC)

Recruiting

Irving, Texas, United States, 75063

US Oncology Investigational Products Center (IPC)

Recruiting

Irving, Texas, United States, 75063

Texas Oncology - San Antonio

Recruiting

New Braunfels, Texas, United States, 78130

Texas Oncology - Gulf Coast

Recruiting

Pearland, Texas, United States, 77584

Texas Oncology - San Antonio

Recruiting

San Antonio, Texas, United States, 78217

Texas Oncology - San Antonio

Recruiting

San Antonio, Texas, United States, 78240

Texas Oncology - San Antonio

Recruiting

San Antonio, Texas, United States, 78258

Texas Oncology - Gulf Coast

Recruiting

Sugar Land, Texas, United States, 77479

Texas Oncology - Gulf Coast

Recruiting

The Woodlands, Texas, United States, 77380

Texas Oncology - Gulf Coast

Recruiting

Webster, Texas, United States, 77598

Oncology & Hematology Associates of Southwest Virginia, Inc., DBA Blue Ridge Cancer Care

Recruiting

Blacksburg, Virginia, United States, 24060

Virginia Oncology Associates

Recruiting

Chesapeake, Virginia, United States, 23320

Virginia Oncology Associates

Recruiting

Hampton, Virginia, United States, 23666

Oncology & Hematology Associates of Southwest Virginia, Inc., DBA Blue Ridge Cancer Care

Recruiting

Low Moor, Virginia, United States, 24457

Virginia Oncology Associates

Recruiting

Newport News, Virginia, United States, 23606

Virginia Oncology Associates

Recruiting

Norfolk, Virginia, United States, 23502

Oncology & Hematology Associates of Southwest Virginia, Inc., DBA Blue Ridge Cancer Care

Recruiting

Roanoke, Virginia, United States, 24014

Oncology & Hematology Associates of Southwest Virginia, Inc., DBA Blue Ridge Cancer Care

Recruiting

Salem, Virginia, United States, 24153

Virginia Oncology Associates

Recruiting

Virginia Beach, Virginia, United States, 23456

Virginia Oncology Associates

Recruiting

Williamsburg, Virginia, United States, 23188

Oncology & Hematology Associates of Southwest Virginia, Inc., DBA Blue Ridge Cancer Care

Recruiting

Wytheville, Virginia, United States, 24382

More Information

Sponsor

Pfizer

Last update posted

Aug 17, 2026

Last verified

Aug, 2026

Keywords

small cell lung cancer
extensive stage small cell lung cancer
first-line

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-08. This information was provided to ClinicalTrials.gov by Pfizer on 2026-08-17.