Discontinuation versus continuation of imatinib for advanced GIST: exploratory long-term follow-up of the multicenter phase 3 BFR14 trial

The long-term impact of tyrosine kinase inhibitor discontinuation on resistance and survival in patients with advanced GIST is unclear. In the phase 3 BFR14 trial, at 17 centers in France, patients with advanced GIST received oral imatinib 400 mg daily. At one, three, and five years from start of treament, patients with response or stable disease were randomized to treatment discontinuation until progression (interruption group) of treatment continuation until progression (continuation group). Primary endpoint was progression-free survival. Median PFS in the interruption group versus the continuation group after one year of imatinib was 6.1 months versus 27.8 months (HR 0.35; p=0.0003); after three years of imatinib 7.0 months versus 67.0 months (0.15; p<0.0001); and after five years of imatinib was 58.6 months versus not reached (0.24; p=0.049). Median overall survival after one year of imatinib was 56.0 months versus 105.0 months (HR 0.84; p=0.57); after three years of imatinib 104.0 months versus 134.0 months (0.40; p=0.0096); and after five years of imatinib not reached versus 110.4 months (1.28; p=0.67). The authors conclude that imatinib interruption in patients with GIST without progressive disease is not recommended.