Impact of mutational status and other prognostic factors on survival in patients with advanced GIST treated with standard-dose imatinib (IM): Results from the BFR14 phase III trial of the French Sarcoma Group.

10548 Background: Factors predicting progression free survival (PFS) and overall survival (OS) of patients (pts) with advanced GIST treated with 400 mg daily dose IM were investigated. As mutational status was a secondary objective of the BFR14 study, we wanted to evaluate the added value of these genomic profiles to conventional clinical prognostic factors. Methods: 434 pts were included in this prospective multicenter trial from June 2002 to July 2009. Prognostic factors for survival were investigated in the cohort where the mutational status was available. A multivariate Cox model including baseline characteristics statistically significant in univariate were included in a backward procedure to identify independent prognostic factors for PFS then OS. Results: Mutational analysis were available in 322 pts. Material was insufficient in 55 cases (12.5%), incomplete results were obtained in 39 pts (9%). There were 196 KIT genetic alterations (exon 11: 173 pts, exon 9: 22 pts, exon 17: 1 pt), 6 GIST with a ...