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Study of GSK6042981 compared to sunitinib for patients with gastrointestinal stromal tumors that spread or cannot be removed after imatinib treatment

Verified siteInvestigationalNo placebo
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What is this trial about?

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

This study is looking at a type of cancer called gastrointestinal stromal tumors, which are growths that occur in the digestive system. The study involves patients whose cancer has spread to other parts of the body or cannot be removed by surgery, and who have already received treatment with a medicine called imatinib but their disease has gotten worse or they could not tolerate that treatment. The study will compare two different medicines: GSK6042981, which is an experimental drug given as a tablet, and sunitinib malate, which is given as a capsule. Both medicines work as tyrosine kinase inhibitors, which are drugs that block certain proteins that help cancer cells grow.

The purpose of the study is to see if GSK6042981 works better than sunitinib malate in slowing down the growth of the cancer or stopping it from getting worse. Patients taking part in this study will be randomly assigned to receive either GSK6042981 or sunitinib malate, and both groups will know which medicine they are receiving. During the study, doctors will monitor how well the treatment is working and how long patients can go without their disease getting worse. Patients will also be asked about their quality of life and any side effects they may experience.

Throughout the study, doctors will collect tissue samples from tumors for laboratory testing, which may come from previously stored tissue or from a new biopsy. The study will also measure the levels of GSK6042981 in the blood and track various aspects of patient health, including how long patients live, how quickly the tumor responds to treatment, and whether the cancer gets worse after starting a different treatment following the study medicine. Patients will complete questionnaires about their symptoms and overall well-being to help researchers understand how the treatments affect daily life.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Treatment assignment

    Upon joining the study, you will be randomly assigned to receive either IDRX-42 (GSK6042981) or sunitinib malate. This random assignment ensures that the comparison between the two treatments is fair.

    Both medications are taken by mouth in the form of tablets or capsules.

  2. Step 2

    Tissue sample submission

    A sample of your tumor tissue will need to be provided to a central laboratory for analysis. This sample can come from tissue that was previously collected and stored, or from a new biopsy if necessary.

    This tissue will be analyzed for biomarkers, which are biological indicators that may help understand how the disease responds to treatment. The sample does not need to be submitted before you begin treatment.

  3. Step 3

    Study treatment period

    You will receive your assigned treatment according to the dosing schedule determined by the study. The specific dosage, frequency, and duration of treatment will be provided to you by the study team.

    If you are assigned to receive IDRX-42 (GSK6042981), you will take this medication orally as directed.

    If you are assigned to receive sunitinib malate, you will take this medication orally as directed.

    Treatment will continue until your disease progresses, you experience unacceptable side effects, or you decide to stop participating.

  4. Step 4

    Disease monitoring

    Throughout the study, your disease will be monitored regularly to assess whether it is responding to treatment, remaining stable, or progressing.

    The primary focus will be on measuring progression-free survival, which is the length of time during and after treatment that your disease does not get worse.

    Your response to treatment will also be evaluated, including whether tumors shrink or disappear.

  5. Step 5

    Safety monitoring

    Your health and any side effects you experience will be monitored closely throughout the study.

    Information will be collected about any adverse events, which are unwanted or harmful effects that may occur during treatment. This includes both mild and serious events.

    Blood samples will be taken at specified times to measure the levels of IDRX-42 (GSK6042981) in your bloodstream if you are assigned to that treatment group.

    If you experience side effects, your dose may be reduced, temporarily stopped, or discontinued depending on the severity.

  6. Step 6

    Quality of life assessments

    You will be asked to complete questionnaires at regular intervals to assess your quality of life and how you are feeling.

    These questionnaires will ask about your physical functioning, symptoms, and overall well-being.

    You will also be asked to report any symptoms or side effects you are experiencing and how bothersome they are to you.

  7. Step 7

    Follow-up after treatment

    If your disease progresses during the study or you stop treatment for another reason, you will continue to be followed to monitor your overall survival and any subsequent treatments you receive.

    Information will be collected about the time until your disease progresses again after starting a new treatment, if applicable.

Who can join the trial?

5 criteria

  • You must have a confirmed diagnosis of GIST (a type of tumor that starts in the digestive system) that has spread to other parts of the body or cannot be removed by surgery
  • Your disease must have gotten worse while taking imatinib (a cancer medicine), or you were unable to tolerate imatinib when it was used as your first treatment for disease that had spread or could not be removed by surgery
  • A sample of your tumor tissue must be available to send to a laboratory for testing. This sample can be from tissue stored from a previous biopsy (a procedure where a small piece of tissue is removed for examination) or from a new biopsy
  • You can be male or female
  • You must be an adult to participate in this study

Who cannot join the trial?

4 criteria

  • The source data does not provide specific exclusion criteria (reasons why a patient cannot participate) for this clinical trial
  • Without detailed exclusion criteria information, it is not possible to list the specific conditions or situations that would prevent participation in this study
  • Exclusion criteria typically include things like other medical conditions, previous treatments, laboratory test results, or medications that would make it unsafe or inappropriate for someone to join the trial
  • The available information only indicates this study involves patients with gastrointestinal neoplasms (tumors in the digestive system), specifically GIST (a type of tumor that grows in the digestive tract), who have tried imatinib therapy (a cancer medication) without success
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Investigated drugs

  • IDRX-42 (GSK6042981)

    is an investigational medication being studied as a treatment for gastrointestinal stromal tumors, which are a type of tumor that can occur in the digestive system. This medication is being tested to see if it can help control the growth and spread of these tumors in patients whose cancer has gotten worse despite previous treatment with another medication called imatinib.

  • Sunitinib

    is an approved cancer medication that works by blocking certain proteins that help tumors grow and spread. In this study, it is being used as a comparison treatment to see how well the investigational medication works against it. Sunitinib is already used to treat gastrointestinal stromal tumors in patients whose cancer has progressed after other treatments.

What is already known about the treatment

  • IDRX-42 (GSK6042981)

    This medication is currently being studied in clinical trials as a treatment for gastrointestinal stromal tumors (GIST), which are a type of cancer that occurs in the digestive system. It is being tested in patients whose cancer has spread or cannot be removed by surgery, specifically after previous treatment with another medication called imatinib has stopped working. The drug is being compared to sunitinib, an existing treatment option, to determine if it can better delay cancer progression. IDRX-42 is administered as part of an open-label study, meaning both doctors and patients know which treatment is being given, and it belongs to a class of medications designed to target specific cancer cells.

  • Sunitinib

    This is an approved cancer medication that works by blocking certain proteins that help cancer cells grow and spread, while also preventing the formation of new blood vessels that tumors need to survive. It is taken by mouth, usually in capsule form, and is commonly used to treat gastrointestinal stromal tumors when other treatments like imatinib have failed. Sunitinib belongs to a group of drugs called tyrosine kinase inhibitors, which specifically target enzymes involved in cancer cell growth. In this clinical trial, it serves as the comparison treatment to evaluate whether the new drug IDRX-42 might work better for patients with advanced GIST.

Investigated diseases

Gastrointestinal Stromal Tumor – A rare type of cancer that develops in the digestive system, most commonly in the stomach or small intestine. This tumor originates from special cells in the wall of the gastrointestinal tract called interstitial cells of Cajal, which help control the movement of food through the digestive system. The disease can range from small, slow-growing tumors to larger, more aggressive forms that spread to other parts of the body. When the tumor advances, it may become metastatic, meaning it spreads beyond its original location to other organs. Some tumors also become unresectable, which means they cannot be removed through surgery due to their size, location, or extent of spread. The disease may continue to progress even after initial treatment, requiring additional therapeutic approaches.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-522229-37-00Protocol code300383Estimated enrolment450 patientsSponsorGlaxosmithkline Research & Development Limited

sourced from the EU Clinical Trials Register and site verification

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