ORLANDO (EGMN) - Plasma levels of imatinib were associated with clinical benefit in a retrospective review of 73 patients with unresectable or metastatic gastrointestinal stromal tumors.Patients with the lowest circulating levels of imatinib (Gleevec) had lower rates of clinical benefit and shorter time to progression, whereas patients with higher imatinib exposure had better overall rates of benefit and longer progression-free intervals, as reported by an international research team January 25 at...