UPCC 20525 A Phase 3, Randomized, Multicenter, Open-Label Study of IDRX-42 (GSK6042981) versus Sunitinib in Participants with Metastatic and/or Unresectable Gastrointestinal Stromal Tumors (GIST) after Imatinib Therapy (StrateGIST 3)

Study of Investigational Treatment Versus Sunitinib for Gastrointestinal Stromal Tumors

Enrolling By Invitation
18 years or above
All
Phase 3
450 participants needed
1 Location

Brief description of study

The purpose of this study is to find out if a new drug, called IDRX-42 (also known as GSK6042981), is effective in treating adults with a type of cancer called Gastrointestinal Stromal Tumors (GIST) when compared to another drug named sunitinib. The study will see if IDRX-42 works well and is safe for participants whose GIST has spread or cannot be surgically removed, and who have already taken the drug imatinib. Participants whose disease worsens after receiving sunitinib in this study may cross over to receive GSK6042981, at investigator's discretion and if additional eligibility criteria are met.

Eligibility of study

You may be eligible for this study if you meet the following criteria:

  • Conditions: Gastrointestinal Neoplasms
  • Age: 18 years or above
  • Gender: All

Inclusion Criteria:

  • Participants with histologically or cytologically confirmed GIST that is metastatic and/or surgically unresectable.
  • Documented disease progression on or intolerance to imatinib administered for first-line treatment of unresectable/metastatic disease.
  • Documented mutation status of KIT and/or PDGFRA using a tissue based next-generation sequencing or polymerase chain reaction (PCR) assay.
  • Tumor tissue must be available for retrospective biomarker analysis. Sample may be archival or new biopsy.

Exclusion Criteria:

  • GIST that is both KIT and PDGFRA wild-type or known to harbor an activating PDGFRA exon 18 mutation.
  • Known untreated or active central nervous system metastases.
  • Participants with a known allergy or hypersensitivity to any component of IDRX-42 (GSK6042981) or sunitinib. Participants with a history of Stevens-Johnson syndrome on a prior Tyrosine kinase inhibitor (TKI) are excluded.
  • Has a malignancy (except disease under study) that has progressed or required active treatment within the past 24 months except for basal cell or squamous cell carcinomas of the skin or in-situ carcinomas (e.g., breast, cervix, bladder) that have been resected with no evidence of metastatic disease.

This study investigates the treatment of Gastrointestinal Stromal Tumors (GIST).

The study evaluates the effectiveness and safety of an investigational medication compared to sunitinib in adults whose GIST has spread or cannot be removed by surgery.

  • Who can participate: Adults with metastatic or surgically unresectable GIST who have progressed on or are intolerant to imatinib may join. Documented mutation status of KIT and/or PDGFRA is required.
  • Study details: Participants will receive either the investigational treatment or sunitinib. An inactive substance called a placebo is not used in this study.
Updated on 12 Jun 2026. Study ID: 25-2095
If you need assistance finding a non-cancer clinical research study or if you have any questions, please email psom-ocr@pobox.upenn.edu For Cancer trials contact Penn Medicine's Cancer Trial Navigator at: PMCancerResearch@pennmedicine.upenn.edu or 215-349-8245

Study is selecting its participants from a population, or group of people, decided on by the researchers in advance.

Contact Abramson Cancer Center Navigator