Background
Phase III RCT. 908 patients with completely resected intermediate- or high-risk GIST (2002 NIH classification). Designed to test whether 2 years of adjuvant imatinib improves overall survival.
Interventions and follow up
Arm A: imatinib 400mg daily for 2yr
Arm B: observation
Primary endpoint: Overall survival (OS)
mFollow up: 4.7yr
Arm B: observation
Primary endpoint: Overall survival (OS)
mFollow up: 4.7yr
Results
5-yr OS: 100% vs 99%, not significant
IFFS (imatinib failure-free survival; time to death or to a non-imatinib TKI): 87% vs 84%, not significant
3-yr RFS: 84% vs 66%, P<.001
5-yr RFS: 69% vs 63%, P<.001
IFFS (imatinib failure-free survival; time to death or to a non-imatinib TKI): 87% vs 84%, not significant
3-yr RFS: 84% vs 66%, P<.001
5-yr RFS: 69% vs 63%, P<.001
Adverse events
Constitutional / GI: fatigue, diarrhea, nausea common with imatinib
Dermatologic: rash
Discontinuation for AEs: approximately 5-10%; 2 years of adjuvant imatinib generally well tolerated
Dermatologic: rash
Discontinuation for AEs: approximately 5-10%; 2 years of adjuvant imatinib generally well tolerated
Conclusions
Adjuvant imatinib delayed recurrence (improved RFS) but did not improve overall survival or imatinib failure-free survival, consistent with high salvage rates with TKIs at relapse.
Key Limitations
Primary OS endpoint negative and underpowered given very high survival in both arms; included intermediate-risk patients who derive less benefit; 2-year duration is intermediate between the 1- and 3-year regimens tested elsewhere; RFS benefit largely lost after treatment stops.
Clinical Context
EORTC 62024 reinforces that adjuvant imatinib delays rather than prevents recurrence. ESMO/ASCO recommend 3 years of adjuvant imatinib for high-risk resected GIST (per SSG XVIII), reserving observation or shorter therapy for lower-risk tumors. IFFS is a relevant surrogate when most relapses remain TKI-sensitive.