Budget Impact Analysis of Discontinuing Tyrosin Kinase Inhibitors in Patients With Chronic Myeloid Leukemia Achieving a Complete Molecular Response by Using Probabilistic Markov Approach

Chronic myeloid leukemia (CML) is a model of targeted therapy for human malignancies. Over the past decade, a broad array of drugs designed to selectively inhibit protein tyrosine kinases (PTK) \[i.e., tyrosine kinase inhibitors, (TKI)\] have emerged as novel therapies for cancer patients. Hence, CML is an hematopoietic stem cell disorder in which a t(9;22) (q34;q11) reciprocal chromosomal translocation gives rise to Philadelphia chromosome (Ph) and generates the BCR-ABL1 fusion gene encoding a constitutively activated PTK. TKIs, such as imatinib by blocking BCR-ABL1 kinase activity, selectively eradicate CML cells and induce durable responses and prolong survival. CML patients treated with TKI are monitored by quantitative RT-PCR to detect leukemic BCR-ABL1 transcript performed from peripheral blood samples (1). Since TKI treated CML patients have a near-normal life expectancy two important issues must be considered in the future: 1. the quality of life and ethical aspects of a lifetime treatment, 2. the budget impact for healthcare providers of treating patients during lifetime. One of the best ways to consider these two points is to ask the question about stopping TKI in good responder patients. We first reported a pilot study where imatinib was withdrawn in 12 CML patients treated and maintained in complete molecular remission (CMR), defined by undetectable residual disease (with sensitivity of 4.5 log) on quantitative RT-PCR, for at least two years. Then, we demonstrated in a multicenter study entitled STIM trial that imatinib could be safely discontinued in patients with CMR for at least 2 years (2). All molecular relapsing patients were sensitive when imatinib was re-challenged (3). Around 40% of these patients remain in a prolonged treatment-free remission (TFR) after treatment cessation (4). Taking into account the cost of imatinib and the number of months without treatment in STIM trial, the savings in France were estimated to be 9 million €. However, s