This study will assess the maximum tolerated dose of low dose interferon in conjunction with nilotinib in pretreated Philadelphia chromosome positive (Ph+) chronic myeloid leukemia patients in chronic phase (CML-CP).

Inclusion Criteria:

• Patients with chronic myeloid leukemia in chronic phase (CML-CP) at screening
• Initial diagnosis of CML cytogenetically confirmed by the presence of the Ph+ metaphases from the bone marrow
• Patients who have been treated with nilotinib for a minimum of 6 months (1 month represents 28 days) after switch from previous CML treatments
• Patients who have been treated with stable dosing of 2x400mg nilotinib within the last month before start of study treatment
• No grade 3-4 CTC toxicities on nilotinib alone in the last month preceding the start of the study regimen

Exclusion Criteria:

• Patients who are considered Ph- because they do not have a confirmed cytogenetic diagnosis of the t(9;22) translocation in their bone marrow metaphases
• Evidence of a point mutation within the BCR-ABL gene leading to a clinically relevant amino acid exchange in the kinase domain at position T315 (gatekeeper mutation T315I)
• Impaired cardiac function
• Severe or uncontrolled medical conditions (i.e. uncontrolled diabetes, active or uncontrolled infection).

Other protocol-defined inclusion/exclusion criteria may apply