Correlation between IPP or IC₅₀ and clinical response for dasatinib and nilotinib. IPP was calculated based on drug IC₅₀ and slope of in vitro response of Ba/F3 cells expressing various BCR-ABL mutations and on population pharmacokinetic mean peak concentrations in plasma reported for each drug. Mutations were divided into 2 groups for dasatinib (A-B) and nilotinib (C-D) based on cutoff values of IPP (nondimensional) or IC₅₀ (nM) as indicated. For each group, clinical response analysis was based on previously published mutation-specific rates of complete cytogenetic response (CCyR),^5,6 and the median, range, and 25th and 75th percentiles are shown.