Prospective single-center study of chronic myeloid leukemia in chronic phase: switching from branded imatinib to a copy drug and back.

Imatinib (Glivec(®)/Gleevec(®)) has shown long-term efficacy and safety in randomized trials. No large-scale studies have prospectively assessed the benefit-risk profile of an imatinib copy drug. We prospectively evaluated the response of patients with chronic myeloid leukemia in chronic phase in one institution. Patients with a complete hematologic response (n = 126) switched from branded imatinib to an imatinib copy drug. Subsequently, all patients switched back to the branded imatinib. Many patients in this study had a loss of hematologic response and tolerability issues with the imatinib copy drug. Hematologic response and tolerability improved upon retreatment with branded Glivec.