Masitinib in comparison to imatinib as first-line therapy of patients with advanced gastrointestinal stromal tumor (GIST): A randomized phase III trial.

TPS10102^ Background: Masitinib is an oral tyrosine kinase inhibitor (TKI) that has greater in vitro kinase activity and/or selectivity than imatinib against KIT and PDGFRA/B. A phase 2 study has previously reported that masitinib treatment produced clinically relevant activity in imatinib-naive patients with advanced GIST. Considering the promising long term response observed in overall survival (OS) (see Table) there is compelling evidence to compare masitinib against imatinib (the current standard of care) in the first-line setting. Methods: A multicenter, randomized, open label, phase 3, 1:1 study to compare efficacy and safety of masitinib (7.5 mg/kg/day) to the active control of imatinib (400 or 600 mg/day) in first-line treatment of patients with advanced GIST. Primary endpoint is progression-free survival (PFS), with secondary endpoints including OS, time to progression (TTP), and clinical response rates (RECIST). Based on a planned sample size of 222 patients (111/arm) this 15% non-inferiority st...