Dose escalation of imatinib after failure of standard dose in Korean patients with metastatic or unresectable gastrointestinal stromal tumor.

OBJECTIVE: We evaluated the results of imatinib dose escalation in patients with advanced gastrointestinal stromal tumors (GISTs) after disease progression on standard-dose imatinib. METHODS: Clinical data from patients with metastatic or unresectable GISTs whose dose of imatinib was increased after disease progression on imatinib 400 mg/day were retrospectively reviewed. RESULTS: The 24 patients studied had a median age of 52 years. Imatinib dosing was escalated to 600 mg/day in 12 patients, then to 800 mg/day in four patients. The other 12 patients had dose escalation directly to 800 mg/day. Two patients (8.3%) achieved a partial response, and seven (29.2%) had stable disease. Six-month progression-free and overall survival rates were 33.3 and 70.7%, respectively. Dose escalation to 600 or 800 mg/day was generally well tolerated. CONCLUSION: Imatinib dose escalation is feasible and well tolerated in patients with advanced GIST who progress on standard-dose therapy, producing clinical benefit in approximately 37% of patients.