Effect of five years of imatinib on cure for patients with advanced GIST: Updated survival results from the prospective randomized phase III BFR14 trial.

Abstract

10095 Background: We previously demonstrated that interruption of imatinib (IM) after 1, 3, and 5 yrs in responding patients (pts) with advanced GIST is associated with rapid relapse but reintroduction of IM allowed tumor control in almost all pts. Here, we examined the outcome of patients randomized in the interruption arm (I arm), and notably the characteristics of those not yet progressing. Methods: This prospective multicenter BFR14 study was initiated in June 2002 and closed for inclusion in July 2009. Seventy-one non-progressing patients were randomized in the I arm after 1 (N=32), 3 (N=25) and 5 years (N=14) of IM 400 mg/day. IM (same dose) was reintroduced in case of progressive disease (PD). Results: The median follow-up (FU) from randomization was 74, 48 and 22 months for pts randomized at 1, 3 and 5 yrs of IM treatment respectively. Updated survival data (January 2012) are summarized in the table. Out of the 3 pts not progressing in the I arm at 1 yr, 1 pt had refused to stop IM and 1 pt had a localized GIST with small residual disease at inclusion. Out of the 3 pts not progressing in the I arm at 3 yrs, 1 pt had refused to stop IM and 2 pts were included after complete resection of both primary tumor and metastases with a small residual disease. The FU of pts randomized at 5 yrs was short but out of the 5 non progressive pts, 2 are considered in PD on functional imaging (January 2012), 2 had a locally advanced GIST subsequently operated during IM and before randomization, and 1 had no target lesion at inclusion (resection of synchronous metastases). Conclusions: All but one pts with residual masses under IM and randomized in the I arm have relapsed. Six out of 7 patients not yet progressing in the I arm had reached complete remission following surgery at inclusion or before randomization (initial resection/debulking of metastases). [Table: see text]