A Phase II Trial of Imatinib Mesylate as Maintenance Therapy for Patients With Newly Diagnosed C-kit–positive Acute Myeloid Leukemia

Introduction: Adults with acute myeloid leukemia (AML) have a high rate of remission; however, more than 50% relapse. C-kit is expressed in approximately 60% of patients with de novo AML and represents a potential therapeutic target. Materials and Methods: Patients with newly diagnosed AML received 12 months of imatinib mesylate as maintenance therapy after the completion of post-remission therapy. The primary objective was to determine whether this approach improved progression-free survival (defined as no relapse and no death) compared with historical controls. Results: The median progression-free survival of patients < 60 years of age was 52.1 months (historical control, 13 months) and for patients ≥ 60 years of age was 10.7 months (historical control, 8 months). The median level of AF1q expression was high (9.59), and 84% of patients had moderate or high levels of drug-resistance factors. Conclusions: Imatinib maintenance therapy may improve the outcome of newly diagnosed patients with AML who are < 60 years of age. The prognosis of acute myeloid leukemia remains poor, and novel treatments are needed. C-kit is expressed on the surface of acute myeloid leukemia cells and represents a potential target. This trial examined the addition of the c-kit inhibitor, imatinib, for 12 months after the completion of chemotherapy. The addition of imatinib appeared to improve outcomes in patients < 60 years of age.