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.
Age range
18 Years
Sex
ALL
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AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
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
Timeframe: Up to approximately 2 years after completion of study treatment of last study participant
Phase 2: Number of participants with treatment-emergent adverse events
Timeframe: Up to 90 days after the last dose of treatment
Phase 3: Overall Survival (OS)
Timeframe: Up to approximately 2 years after completion of study treatment of last study participant
Pfizer CT.gov Call Center