Impact of Genetic Mutations and Health Plan Access to Therapies on Treatment Response and Drug Costs Related to Tyrosine Kinase Inhibitor Treatment Among Patients With Chronic Myelogenous Leukemia.

OBJECTIVES: This study assessed treatment responses and economic consequences of limiting access to the second-generation BCR-ABL1 tyrosine kinase inhibitors (2G-TKI), dasatinib and nilotinib, for treatment of chronic myelogenous leukemia, while taking into account frequencies of genetic mutations that exhibit different sensitivities to the 2G-TKIs. METHODS: Frequencies of BCR-ABL1 mutations and the impact of mutations on responses to 2G-TKIs were obtained from published literature and used as inputs in a decision analytics model. Complete hematologic response (CHR) and major cytogenetic response (MCyR) were estimated after 12 months of 2G-TKI treatment. Total annual 2G-TKI drug costs per CHR and MCyR were estimated and compared among 3 2G-TKI access scenarios: (1) open access to both 2G-TKIs; (2) access restricted to dasatinib (DASA-only); and (3) access restricted to nilotinib (NILO-only). RESULTS: Among a hypothetical cohort of 1000 2G-TKI-treated chronic myelogenous leukemia patients, the percentage of patients with CHR and MCyR were greatest for the open access plan (CHR: 93%, MCyR: 56%), followed by DASA-only (88%, 53%) and NILO-only (67%, 47%). Compared with the 2G-TKI costs per CHR in open access ($120,706/CHR), the costs were 5% higher ($126,753/CHR) in DASA-only and 41% higher ($169,990/CHR) in NILO-only. Likewise, compared with the 2G-TKI costs per MCyR in open access ($198,284/MCyR), the costs were 6% higher ($209,259/MCyR) in DASA-only and 22% higher ($241,515/MCyR) in NILO-only. CONCLUSION: Open access to both 2G-TKIs is associated with improved clinical and economic outcomes: greater treatment response rates (CHR and MCyR) and lower drug costs compared with restricted access to 2G-TKIs.