Background: The introduction of tyrosine kinase inhibitors (TKIs) into clinical practice resulted in a very dramatic prolongation of survival for most, but not all patients with chronic myeloid leukemia (CML) in chronic phase. If properly managed, and if adherence is greater than 80%, the 10-year survival rate reaches 85% for patients treated with the 1st-generation (Gen) TKI, imatinib (Gleevec). Currently, there are five TKIs available for CML. Clinicians must weigh the relative advantages and toxicities of each when selecting a course of treatment. Three TKIs are approved for frontline therapy in CML—imatinib, nilotinib (Tasigna), and dasatinib (Sprycel). The 2nd-Gen TKIs (nilotinib, dasatinib) produce more rapid responses but have yet to show any overall survival advantage compared with long-term administration of imatinib. The 3rd-Gen TKI, ponatinib (Iclusig), looks promising but clinical data are still immature, and it is only approved for salvage therapy. Current practice is a 30-40% start with 2nd-Gen TKIs. Both nilotinib and dasatinib are more expensive than imatinib, a difference expected to become more dramatic once imatinib is no longer patent-protected in late 2015. Given its cost-effectiveness, it is still reasonable to initiate imatinib as 1st-line treatment for CML in appropriate patients. This would maximize the cost avoidance with respect to initiating CML therapy with a 2nd-Gen TKI.
Objective: To determine the cost-avoidance of initiating patients with imatinib for chronic-phase CML compared to 2nd-Gen TKIs.
Method: Chronic-phase CML patients will be started with imatinib where appropriate. Molecular testing was recommended at 90 days from day 1 of initiated TKI therapy to determine BCR-ABL transcript levels. The results would determine whether to continue with imatinib or switch to a 2nd-Gen TKI as was similarly done by David Marin, et al. (Marin D, et al. JCO. 2012;30(3):232-238).
Results: From October 2011 to January 2013, 92% of CML patients in chronic phase were prescribed imatinib 1st-line compared to 8% of patients that were initiated with a 2nd-Gen TKI. Potential cost avoidance and need to switch to another TKI will be reported.
Conclusion: Second-generation TKIs are increasing utilization in frontline therapy for CML. To date, there is no survival benefit. Patients who fail imatinib can be salvaged effectively with 2nd-Gen TKIs. It is reasonable to initiate CML therapy with imatinib without compromising efficacy and long-term outcomes in appropriate patients.
