PIA assay for FLT3 using plasma samples from patients treated with PKC412. Trough plasma samples from 10 patients receiving 75 mg PKC412 orally every 8 hours were used in a PIA assay for FLT3. The results are expressed as percent baseline. Each bracket marks a set of samples from the same patient, and the patient numbers correspond to the numbering used by Stone et al.⁴  For each patient, PIA results from day 3, day 8, and day 28 of treatment with PKC412 are shown. A day-8 sample was not available for patient 9, and a day-28 sample was not available for patient 19. For some samples,^11,12  some of the columns are not visible because FLT3 phosphorylation was completely suppressed.