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RecruitingRare disease

Phase 3 Study of GSK6042981 versus Imatinib in Adults with Previously Untreated Metastatic or Unresectable Gastrointestinal Stromal Tumors (GIST)

Verified siteInvestigationalNo placebo
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What is this trial about?

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

The study focuses on Gastrointestinal Stromal Tumor, a rare cancer that begins in the connective tissue of the digestive tract. Participants have disease that is either metastatic, meaning it has spread beyond its original site, or unresectable, meaning it cannot be removed completely by surgery. The trial compares two oral tablets: the experimental drug velzatinib (code name GSK6042981) and the established therapy imatinib. Both medicines are taken by mouth in tablet form.

The purpose of the trial is to determine whether the new medicine works as well as, or better than, the standard treatment in patients who have not received prior therapy for this condition. This phase 3 investigation uses a randomized, open-label design, meaning participants are assigned by chance to one of the two drugs and both the study team and participants know which drug is being taken. After enrollment, participants receive daily medication and attend regular clinic visits for safety checks and imaging scans that monitor the tumor. The study follows each person until the cancer shows signs of worsening, which is measured as progression-free survival, or until side effects require stopping the medication.

The research process

The trial runs in 9 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Randomization

    After enrollment, you will be assigned by a computer system to receive either velzatinib (the test medication) or imatinib (the comparator medication). this process is called randomization and ensures that the assignment is unbiased.

  2. Step 2

    Start study medication

    You will begin taking the assigned medication in the form of an oral tablet. the exact dose and frequency are defined by the study protocol and will be explained by the study staff. the tablet is taken by mouth each day as instructed.

  3. Step 3

    Baseline assessments

    Before the first dose, you will undergo baseline tests that may include blood work, an electrocardiogram (ecg), and imaging scans to document the current status of your disease.

  4. Step 4

    Regular safety visits

    You will attend clinic visits regularly, typically every four to six weeks. during these visits, study staff will check your vital signs, review any side effects (called adverse events), and may perform additional blood tests.

  5. Step 5

    Periodic disease assessments

    Imaging studies such as CT or MRI scans will be performed at scheduled intervals, often every eight weeks, to evaluate whether the tumor is stable, shrinking, or growing. this information helps determine progression, which means the disease is getting worse.

  6. Step 6

    Reporting side effects

    You are asked to inform the study team promptly about any new symptoms or changes in how you feel. these reports help the team manage safety and decide if any changes to treatment are needed.

  7. Step 7

    Dose adjustments if needed

    If you experience significant side effects, the study protocol may allow a dose reduction, a temporary pause, or discontinuation of the medication. any adjustment will be made by the study physician based on your condition.

  8. Step 8

    Continuation of treatment

    You will continue taking the assigned medication daily for as long as it remains effective and tolerable. treatment continues until one of the following occurs: the disease shows progression, side effects become unacceptable, or the study reaches its planned end.

  9. Step 9

    Final evaluation

    At the end of the study or when treatment stops, a final assessment will be performed to record overall survival and any lasting effects of the medication.

Who can join the trial?

14 criteria

  • Age: You must be at least 18 years old, or old enough to give legal consent where you live.
  • Confirmed diagnosis: Your doctor must have proven that you have gastrointestinal stromal tumor (GIST) by looking at tissue under a microscope (histology or cytology) and the cancer must have spread to other parts of the body (metastatic) or cannot be removed by surgery (unresectable).
  • No previous systemic treatment: You cannot have received any medicines that treat cancer throughout the whole body for this advanced GIST. If you had surgery for an earlier, localized GIST (with or without the drug imatinib) and the cancer came back later, you may join if at least 6 months have passed since the last imatinib dose.
  • Tumor tissue sample: You need to provide a piece of your tumor for testing. This can be an older sample that was saved (preferred) or a fresh biopsy taken before you are randomly assigned to a treatment group.
  • At least one target lesion: You must have at least one measurable tumor that the study can track over time.
  • Contraception: You must agree to use reliable birth control methods or abstain from sexual activity as required by the study. This applies to both men and women and is meant to prevent pregnancy during the trial.
  • Not pregnant or breastfeeding (for women): You must not be pregnant or nursing, and you must have a negative pregnancy test before starting the study.
  • Informed consent: You must be able to read, understand, and sign a consent form agreeing to follow the study rules.
  • ECOG performance status ≤ 1: This means you should be fully active or able to carry out most daily activities without significant limitation.
  • Adequate organ function: Your blood counts, kidney function, and clotting ability must be within normal ranges. This includes:
    • White blood cells (ANC) ≥ 1500 per microliter.
    • Platelets ≥ 90,000 per microliter.
    • Hemoglobin (red blood cell level) ≥ 9.0 g/dL.
    • Kidney function (eGFR) ≥ 30 mL/min.
    • Clotting tests (INR/PT/aPTT) not more than 1.5 times the upper limit, unless you are on blood‑thinning medication and the values are within the therapeutic range.

Who cannot join the trial?

21 criteria

  • You have another cancer (besides the study disease) that has gotten worse or needed treatment in the past 2 years, except for certain skin cancers that were removed and have not spread.
  • You have a serious or unstable medical or mental‑health problem, or abnormal lab test, that could make the study unsafe or make it hard for you to follow the study rules.
  • You received radiotherapy (radiation treatment) within 14 days before the first study dose.
  • You received a live vaccine (a vaccine using a weakened germ) within the past 30 days.
  • You had a blood transfusion (red cells or platelets) or were given medicines that stimulate blood‑cell production (such as G‑CSF, GM‑CSF, or erythropoietin) within 14 days before randomization.
  • You are currently enrolled in, or have taken part in, another clinical trial before signing this study’s consent form.
  • A drug/alcohol screening test was positive for recent use of drugs or alcohol.
  • You have a known HIV infection and any of the following: detectable virus level, no recent CD4‑cell count, CD4 count ≤200, recent changes in HIV medicines, history of HIV‑related cancers, or recent HIV vaccine.
  • You are pregnant or breastfeeding.
  • You are unable to follow the study schedule and required follow‑up visits.
  • Your blood test shows an ALT (a liver enzyme) level more than 2.5 times the normal limit (or more than 5 times if you have liver tumors).
  • You have serious digestive problems that could affect how medicines are absorbed, such as a condition that prevents nutrient absorption or major surgery removing part of the stomach or intestines.
  • Your blood test shows a total bilirubin level more than 1.5 times the normal limit.
  • You have cirrhosis (severe liver scarring) or an unstable liver or bile‑duct disease, shown by fluid in the abdomen, brain changes, blood‑clotting problems, low protein, enlarged veins in the stomach/esophagus, or ongoing yellowing of the skin.
  • You have chronic hepatitis B infection that still shows virus in your blood despite strong antiviral treatment.
  • Your heart test (12‑lead ECG) shows a QTc interval longer than 480 milliseconds, or you have a known long QT syndrome (a condition that can cause abnormal heart rhythms).
  • You have a history of a bone‑marrow or other organ transplant (except certain stem‑cell transplants done more than 100 days ago with no active infection).
  • You are allergic to the study drugs velzatinib or imatinib.
  • You have untreated or progressing brain or central‑nervous‑system (CNS) metastases (cancer spread to the brain).
  • You still have side effects from previous treatment that have not improved to mild (grade 1) or returned to the level before treatment, unless they are minor issues like hair loss, hearing loss, skin color loss, hormone replacement, or mild nerve problems.
  • You have an active kidney problem, such as infection, need for dialysis, or any serious kidney condition.
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Investigated drugs

  • Velzatinib (GSK6042981)

    is an oral medication being tested as a new treatment for people with gastrointestinal stromal tumors (GIST) that cannot be removed by surgery or have spread to other parts of the body. It works by blocking specific proteins inside cancer cells that tell the cells to grow and divide. By stopping these signals, the drug aims to slow down or stop tumor growth.

  • Imatinib mesylate

    is an oral drug that is already approved for treating GIST. It blocks a protein called KIT, which is often over‑active in these tumors and drives their growth. In this study, it is used as the standard treatment to compare how well the new drug works.

What is already known about the treatment

  • Imatinib mesylate

    Oral tablets are taken by mouth. Imatinib is an approved drug that has been used for many years to treat certain cancers, including gastrointestinal stromal tumors. It works by blocking specific proteins called tyrosine kinases (such as BCR‑ABL, KIT, and PDGFR) that tell cancer cells to grow. It belongs to the class of tyrosine‑kinase inhibitors.

  • Velzatinib

    Oral tablets are taken by mouth. Velzatinib is an experimental, orphan‑designated drug currently being studied in clinical trials for gastrointestinal stromal tumors. It blocks the activity of the KIT and PDGFRA tyrosine‑kinase proteins, stopping signals that make tumor cells multiply. It is classified as a tyrosine‑kinase inhibitor.

Investigated diseases

Gastrointestinal stromal tumor - Gastrointestinal stromal tumor is a growth that develops from the connective‑tissue cells of the digestive tract, most often in the stomach or small intestine. It can enlarge within the wall of the organ where it started. The tumor may extend into nearby tissues and, in some cases, spread to distant sites such as the liver or peritoneal cavity. When it spreads or cannot be removed surgically, it is described as metastatic or unresectable. Over time the lesion can increase in size and infiltrate surrounding structures.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-524934-24-00Protocol code306293Estimated enrolment303 patientsSponsorGlaxosmithkline Research & Development Limited

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