- Patients may be receiving nilotinib (Tasigna) as frontline therapy or as second line therapy if the reason for the switch from imatinib to nilotinib was intolerance to imatinib. Patients cannot have been switched from imatinib to nilotinib because of a concern or demonstration for resistance to frontline imatinib. Patients must be on nilotinib for a minimum of 2 years, and be on a stable does for at least one consecutive year leading up to enrollment.