Clinical Trial Follow-Up: Continued Imatinib Significantly Extends Survival and Delays Resistance in Advanced GIST – The Lancet Oncology

Study Design and Population: This exploratory long-term follow-up of the BFR14 open-label, multicenter, randomized phase 3 trial involved patients with advanced gastrointestinal stromal tumors (GIST) across 17 cancer centers in France. The trial included patients aged 18 years or older with stable disease after 1, 3, or 5 years of treatment with imatinib. Participants were randomized to either continue or discontinue imatinib until disease progression, with primary endpoint analysis focused on progression-free survival (PFS).

Main Findings: Imatinib continuation significantly extended PFS compared to discontinuation, with median PFS ranging from 27.8 to over 67.0 months in the continuation group versus 6.1 to 12.0 months in the interruption group, depending on the duration of prior treatment (p-values <0.002). Additionally, continuing imatinib delayed resistance and improved overall survival, particularly notable after 3 years of treatment, with a median overall survival of 134.0 months compared to 104.0 months in the discontinuation group (HR 0.40, p=0.0096).

Implications for Practice: These findings strongly discourage the interruption of imatinib in GIST patients who are stable or responding to treatment, as it leads to worse long-term outcomes, including quicker disease progression and increased resistance to the therapy.

Reference: Blay JY et al. (2024). Discontinuation versus continuation of imatinib in patients with advanced gastrointestinal stromal tumours (BFR14): exploratory long-term follow-up of an open-label, multicentre, randomised, phase 3 trial. Lancet Oncol. http://doi.org/10.1016/S1470-2045(24)00318-8