Gastrointestinal Stromal Tumour (GIST) is a soft tissue tumour that develops in the digestive system, most often in the stomach or small intestine. It is caused by changes in certain proteins that cause the cells to grow uncontrollably. Although current treatments may be effective, tumours may stop responding over time, highlighting the need for newer options. This study is evaluating velzatinib (GSK6042981) in participants with newly diagnosed GIST that has spread or cannot be surgically removed. Velzatinib will be compared with imatinib, the standard treatment, to assess whether it can delay disease worsening and is safe and well tolerated.
Is at least 18 years of age or the legal age of consent in the jurisdiction in which the study is taking place at the time of signing the Informed consent form (ICF).
Has histologically or cytologically confirmed GIST that is metastatic and/or surgically unresectable.
Has not received prior systemic therapy for their metastatic and/or surgically unresectable GIST.
Tumor tissue must be provided to the central laboratory. Tumor tissues may be archival (preferred) or obtained from a fresh biopsy acquired for standard of care (biopsies must be collected before randomization).
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.
Has any clinically significant gastrointestinal abnormalities that may alter absorption, e.g., malabsorption syndrome or major resection of the stomach and/or bowels.
Has had any major surgery (minor surgical procedures such as central venous catheter placement and tumor needle biopsy are not considered major surgical procedures) within 14 days of the first dose of study treatment or participants who have not fully recovered from surgery.
Has any history of prior allogenic or autologous bone marrow transplant or other solid organ transplant. Participants with a history of autologous stem cell transplant are eligible for study participation provided the following eligibility criteria are met: a) transplant was [>100 days] prior to screening, and b) the participant has no active infection(s) at the time of screening.