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Taking people in TaiwanPhase 2/3

Tests PF-08634404 with chemotherapy in extensive-stage small cell lung cancer

Tests a new medicine with chemotherapy in adults with widespread small cell lung cancer.

Key facts

Who runs it
Pfizer
Where
Tainan and Taipei, TaiwanSee the 3 sitesAlso in 9 other countries, 68 sites
Registry title
Symbiotic-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
Status
Recruiting
Phase
Phase 2/3
People taking part
550 people, planned
Started
9 Dec 2025
Expected to end
11 Mar 2034
Type of study
Interventional, 3 groupsOne group gets an existing treatment, for comparison.
Treatments tested
  • PF-08634404
  • Atezolizumab
  • Chemotherapy
Record updated
8 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 extensive-stage small cell lung cancer who have not yet had treatment for it. It tests PF-08634404 given with chemotherapy.

Age
18 years or older
Sex
All sexes can join.
Disease stage
Extensive-stage small cell lung cancer confirmed by lab tests, with at least one measurable tumour spot (RECIST V1.1). Daily activity level (ECOG) of 0 or 1.
Earlier treatment
No earlier systemic treatment (chemotherapy, radiotherapy, chemoradiation) for extensive-stage disease. People treated for limited-stage disease must be treatment-free for at least 6 months.

Main reasons for not taking part

  • Known active spread to the brain or spinal cord, including brainstem or meninges
  • Leptomeningeal disease
  • Clinically significant risk of bleeding or fistula
  • Another cancer within the past 3 years
  • Active autoimmune disease needing systemic treatment within the past 2 years

The registry criteria, word for word

Show all 11 criteriaShow less

Who can take part

  • 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

Who cannot take part

  • 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
  • known active CNS lesions, including brainstem, meningeal, or spinal cord metastases or compression

Where in Taiwan

Also in 9 other countries, 68 sites

  • National Cheng Kung University HospitalTainan, TaiwanTaking people
  • National Taiwan University HospitalTaipei, TaiwanTaking people
  • Taipei Medical University HospitalTaipei, TaiwanTaking people

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

Read full original descriptionShow less

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.

The 3 groups in the trial

  • Phase 2 Single armTreatment being tested

    Participants will receive PF-08634404 in combination with chemotherapy

    Treatment: PF-08634404 and Chemotherapy

  • Phase 3 Experimental ArmTreatment being tested

    Participants will receive PF-08634404 in combination with chemotherapy

    Treatment: PF-08634404 and Chemotherapy

  • Phase3 Control ArmExisting treatment, for comparison

    Participants will receive atezolizumab in combination with chemotherapy

    Treatment: Atezolizumab and Chemotherapy

Questions to ask the study team

  1. How often do I need to come in, and for how long each time?
  2. Are travel costs paid?
  3. Can I keep my own doctor?
  4. What happens if I want to stop?

Contact the study team: see the registry record → Contacts and Locations

Print a page for my doctor

Data and sources

Registry record
Listed on ClinicalTrials.gov and on the EU's official list of trials (CTIS).
Official title
A GLOBAL PHASE 2/3 INTERVENTIONAL STUDY OF PF-08634404 IN COMBINATION WITH CHEMOTHERAPY IN PARTICIPANTS WITH EXTENSIVE STAGE SMALL CELL LUNG CANCER
Plain-language title
Tests PF-08634404 with chemotherapy in extensive-stage small cell lung 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
8 October 2026