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Study comparing GSK5764227 and topotecan in adults with relapsed small cell lung cancer

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study focuses on patients with Small Cell Lung Cancer (SCLC) that has returned after previous treatment. The study will compare two different treatments: a new experimental medication called GSK5764227, which is a type of drug known as a B7-H3 Antibody Drug Conjugate, and an established cancer medication called topotecan. The purpose is to determine how well the new treatment works compared to the standard treatment in fighting the cancer.

The study involves patients whose lung cancer has already been treated with platinum-based chemotherapy combined with immunotherapy but has since returned. Both medications in this study will be given through intravenous infusion (delivered directly into a vein). GSK5764227 will be given at doses up to 8 milligrams per kilogram of body weight, while topotecan will be given at doses up to 1.5 milligrams per square meter of body surface area.

This is an open-label study, which means both the doctors and patients will know which treatment is being given. The treatment period may last up to 24 months, during which time doctors will monitor how well the cancer responds to the treatment and track the overall survival of patients. Throughout the study, patients will have regular check-ups to monitor their health and assess how well the treatment is working.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial evaluation

    Your eligibility for the study will be confirmed based on a diagnosis of extensive stage small cell lung cancer

    Medical tests will verify that you have received previous treatment with platinum-based therapy combined with immunotherapy for at least 2 cycles

    Confirmation that you have at least one measurable tumor outside the brain

    Assessment of your physical condition using the ECOG scale (a measure of daily activity ability) showing a score of 0 or 1

    Laboratory tests to check your organ function, performed 3-5 days before the start of treatment

  2. Step 2

    Treatment assignment

    You will be randomly assigned to receive either GSK5764227 or topotecan

    Both medications will be administered through an intravenous infusion (directly into your vein)

  3. Step 3

    Treatment period

    Regular treatment sessions will be scheduled according to your assigned medication plan

    Your tumor response will be monitored through imaging tests

    Regular assessments will track your overall health status

  4. Step 4

    Follow-up period

    Your health status will continue to be monitored after completing the treatment

    The study is expected to continue until September 2028

Who can join the trial?

9 criteria

  • Must have confirmed small cell lung cancer (SCLC) that has spread beyond the lung (extensive stage), proven by tissue or cell examination
  • Must have previously received only one treatment that included both:
    • platinum-based therapy (a type of chemotherapy) for at least 2 cycles
    • PD-(L)1 inhibitor (a type of immunotherapy that helps your immune system fight cancer)
    • Must have at least one tumor that can be measured outside the brain
    • Must have good physical function ability, rated as ECOG 0 or 1 (able to carry out all or most daily activities), with no worsening in the 2 weeks before starting treatment
    • Must have normal functioning of major organs (such as liver, kidneys, bone marrow). Tests must be done:
      • Initial screening tests: 3-5 days before treatment
      • Final tests: within 24 hours before first treatment
      • Must be an adult (18 years or older)
      • Can be either male or female

Who cannot join the trial?

13 criteria

  • Prior treatment with topotecan (a chemotherapy drug)
  • Known active brain metastases (cancer that has spread to the brain)
  • History of other cancers within the past 3 years, except for successfully treated non-melanoma skin cancer or cervical cancer in situ
  • Significant heart problems including uncontrolled high blood pressure, unstable heart disease, or heart failure
  • Active or chronic infections, including HIV, Hepatitis B, or Hepatitis C
  • Major surgery within 4 weeks before starting the study treatment
  • Participation in another clinical trial within 4 weeks before starting this study
  • Pregnant or breastfeeding women
  • Known allergies to the study medications or their components
  • Severe kidney or liver problems
  • Any condition that could affect the ability to follow study procedures or interpret results
  • Use of medications that could interact with the study drugs
  • Mental conditions that could affect the ability to give informed consent
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Investigated drugs

  • GSK5764227

    is an antibody drug conjugate (ADC) that targets B7-H3, which is being studied as a potential treatment for small cell lung cancer. This medication is designed to specifically target cancer cells while minimizing damage to healthy cells.

  • Topotecan

    is an established chemotherapy medication used to treat various types of cancer, including small cell lung cancer. It works by interfering with the cancer cells' ability to divide and grow. This medication is being used as the comparison treatment in this study.

What is already known about the treatment

  • GSK5764227

    A novel antibody-drug conjugate (ADC) that targets B7-H3, currently being investigated in clinical trials for the treatment of relapsed small cell lung cancer (SCLC). This medication is administered intravenously and belongs to the class of targeted cancer therapies that combine monoclonal antibodies with potent anti-cancer drugs. The mechanism of action involves the antibody specifically binding to B7-H3 proteins on cancer cells, delivering the toxic drug payload directly to tumor cells while minimizing damage to healthy tissue.

  • Topotecan

    An established chemotherapy medication administered intravenously or orally, approved for treating small cell lung cancer and other types of cancer. It belongs to the topoisomerase inhibitor class of drugs and works by interfering with cancer cell DNA replication, ultimately leading to cancer cell death. This medication is commonly used as a second-line treatment option for patients with relapsed small cell lung cancer when initial therapy has failed.

Investigated diseases

Small Cell Lung Cancer - A fast-growing type of lung cancer that develops in the lung tissues, specifically in the bronchi. It usually starts in the cells that look like oats (oat cell cancer) or in mixed smaller cells. The cancer cells multiply quickly and form large masses in the lungs, often spreading early to other parts of the body. This condition is characterized by rapid cell division and growth, making it distinct from other forms of lung cancer. Small cell lung cancer typically begins in the central part of the lungs and can cause symptoms such as persistent cough, chest pain, and breathing difficulties.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-521627-78-00Protocol code223674Estimated enrolment420 patientsSponsorGlaxosmithkline Research & Development Limited

sourced from the EU Clinical Trials Register and site verification

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