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Three versus five years of adjuvant Imatinib as treatment for patients with operable gastrointestinal stromal tumour (GIST) with a high risk for recurrence: SSGXXII: A Randomised phase III study

Three versus five years of adjuvant Imatinib as treatment for patients with operable gastrointestinal stromal tumour (GIST) with a high risk for recurrence: SSGXXII: A Randomised phase III study

Status
Active, not recruiting
Phases
Phase 3
Study type
Interventional
Source
ANZCTR
Registry ID
ACTRN12621001756819
Acronym
SSGXXII
Enrollment
13
Registered
2021-12-22
Start date
2022-02-17
Completion date
2023-05-31
Last updated
2026-08-24

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

The purpose of this study is to compare the effects of 3 years vs. 5 years of imatinib in patients with gastrointestinal stromal tumor (GIST). Who is it for? You may be eligible for this study if you are at least 18 years old, have been diagnosed with GIST, and have been treated with adjuvant imatinib for 3 years after surgery. Study details Once participants have already been receiving their usual standard of care imatinib treatment for 3 years, they will be randomly allocated into two groups. One group will stop their treatment. The other group will receive 400mg oral imatinib once a day for 2 more years. Participants will be followed up and take part in CT/MRI scans, clinical assessments, and questionnaires every few months (ranging from 3-12 month intervals) for 10 years. It is hoped this research will reveal if 5 years of imatinib ensues in better outcomes for GIST patients compared to 3 years of imatinib, thus contributing to improving cancer treatment.

Interventions

Following completion of 35-38 months of standard of care Imatinib treatment (defined as 200-800mg daily oral tablet), patients will be enrolled and randomised to receive continued Imatinib oral tablets at 400 mg/day for 24 months, or to receive no further imatinib treatment. Pharmacy teams will monitor returned imatinib packaging to ensure adherence to the oral medication.

Sponsors

Australasian Gastro-Intestinal Trials Group (AGITG)
Lead SponsorOther Collaborative groups

Study design

Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Open (masking not used)

Eligibility

Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

1, Age >= 18 years. 2. Morphological and immunohistological documentation of GIST (immunostaining for KIT[CD117] and/or DOG-1 positive, or mutation of KIT or PDGFRA present in tumor tissue). 3. Macroscopically complete surgical resection of GIST (either R0 or R1 resection). 4. Mutation analysis of KIT and PDGFR genes has been carried out. 5. A high risk of GIST recurrence; either gastric GIST with mitotic count >10/50 HPFs or >10/5mm2; OR non-gastric GIST with mitotic count >5/50 HPFs or >5/5mm2; OR non-gastric GIST treated with neoadjuvant imatinib and initially larger than 10cm; OR tumor rupture. 6. Eastern Cooperative Oncology Group performance status <= 2. 7. Adequate organ function. 8. Female patients of childbearing potential must have a negative pregnancy test within 14 days before initiation of study drug dosing. Postmenopausal women must have amenorrhea for at least 12 months to be considered of non-childbearing potential. Male and female patients of reproductive potential must agree to employ an effective barrier method of birth control throughout the study and for up to 3 months following discontinuation of study drug. 9. Patient willing to be followed up at the study site regardless of the result of randomization. 10. Patient has provided a written, voluntary informed consent prior to study-specific screening procedures.

Exclusion criteria

1. Presence of distant metastases or local recurrence of GIST. 2. Not willing to donate tumor tissue and/or blood samples for the study molecular studies. 3. Presence of a substitution mutation at PDGFRA codon D842 (usually D842V). 4. Administration of adjuvant imatinib longer than for 3 years is planned regardless of the result of randomization, or "life long" imatinib administration is planned. 5. Prior adjuvant (+ neoadjuvant) therapy with imatinib mesylate for at least 35 months has not been completed, or the total duration of prior adjuvant (+ neoadjuvant) imatinib administration exceeds the total duration of 38 months. 6. Neoadjuvant imatinib for a duration that exceeds 12 months. 7. Longer than 4-week break during adjuvant imatinib administration. 8. The dose of imatinib at completion of 3 years of adjuvant imatinib was 200 mg per day or less or greater than 800 mg per day. 9. Patient has received any investigational anti-cancer agents during adjuvant imatinib or between completion of adjuvant imatinib and the date of randomization. 10. Patient has been free of another malignancy for less than 5 years except if the other malignancy is not currently clinically significant nor requiring active intervention, or if the other malignancy is a basal cell skin cancer or a cervical carcinoma in situ. Recent existence of any other malignant disease is not allowed. 11. Patient with Grade III/IV cardiac disease as defined by the New York Heart Association Criteria (i.e., congestive heart failure, myocardial infarction within 6 months of study entry). 12.Female patients who are pregnant or breast-feeding. 13. Severe and/or uncontrolled medical disease (i.e., uncontrolled diabetes, severe chronic renal disease, or active uncontrolled infection). 14. Known diagnosis of human immunodeficiency virus (HIV) infection. 15. Patient with a significant history of non-compliance to medical regimens or with inability to grant reliable informed consent. 16. Inability or difficulty in swallowing tablets. 17. Patients with chronic or active hepatitis B.

Outcome results

None listed

Source: ANZCTR · Data processed: Aug 31, 2026