Study of Dose Escalation Versus no Dose Escalation of Imatinib in Metastatic Gastrointestinal Stromal Tumors (GIST) Patients

A Randomized, Phase 3 Study of Dose Escalation Versus No Dose Escalation of Imatinib In Metastatic GIST Patients With Imatinib Trough Levels Less Than 1100 Nanograms/mL

The purpose of this study is to determine if escalating the dose of imatinib to keep the drug blood level at ≥ 1100 ng/ml leads to better outcomes for patients.

Inclusion Criteria:

• Age ≥ 18 years
• Unresectable and/or metastatic GIST
• Currently receiving imatinib 400 mg per day for a minimum of 4 weeks prior to registration, and for no more than 6 months prior to registration. This must be the first time that the patient has been treated for metastatic and/or unresectable GIST
• For patients who received imatinib following surgery at the time of an initial diagnosis of GIST, there must be a 6 month interval between completion of imatinib and the diagnosis of metastatic GIST
• Good physical functioning (ECOG Performance Status of 0 or 1)
• Generally, good function of organ such as liver and kidneys

Exclusion Criteria:

• Disease progression during adjuvant therapy with imatinib (adjuvant treatment is treatment that is given after surgery for GIST)
• Known intolerance of imatinib at a dose of 400 mg/day or higher
• Prior systemic therapy for advanced GIST with imatinib or those who have been on imatinib for longer than 6 months for unresectable and/or metastatic disease
• Major surgery within 2 weeks prior to Day 1 of study or who have not yet recovered from prior surgery
• Use of coumadin derivatives (i.e. warfarin, acenocoumarol, phenprocoumon)
• Patients who have received wide field radiotherapy ≤ 4 weeks or limited field radiation for palliation < 2 weeks or who have not recovered from side effects of this therapy