Effects of proprotein convertase subtilisin/kexin type 9 and nilotinib plasma concentrations on nilotinib-induced hypercholesterolaemia in patients with chronic myeloid leukaemia.

ABSTRACT

WHAT IS KNOWN AND OBJECTIVE: The purpose of this study was to investigate the relationships among nilotinib plasma trough concentration (C0 ), low-density lipoprotein (LDL) cholesterol, and PCSK9 plasma concentration in 31 patients with chronic myeloid leukaemia. METHODS: Plasma concentrations of nilotinib and PCSK9 were measured by high-performance liquid chromatography and enzyme-linked immunosorbent assays, respectively. RESULTS AND DISCUSSION: LDL cholesterol concentrations at 1 month after nilotinib treatment were significantly increased compared with those before therapy. The mean C0 (±SD) of nilotinib at 1, 2, and 3 months after nilotinib treatment were 645 ± 516, 902 ± 623, and 951 ± 1088 ng/mL, respectively. Mean PCSK9 concentrations at 3 months after nilotinib treatment were significantly higher than those at the start of therapy (320 vs 257 ng/mL, respectively, P = .019). When the change rate in the PCSK9 concentration induced by nilotinib was classified with a cut-off value of +40%, the change rate in LDL cholesterol in patients with a change rate in PCSK9 of ≥40% was significantly higher than that in patients with a PCSK9 change rate of <40% (67.1% vs 38.0%, P = .043); however, there were no differences in mean nilotinib C0 . WHAT IS NEW AND CONCLUSION: Nilotinib may lead to hypercholesterolaemia by increasing plasma concentrations of PCSK9 after indirect inhibition of mammalian target of rapamycin (mTOR) complex 1. In addition, certain patients seem to have high sensitivity for nilotinib in a signalling cascade of the PI3K/Akt/mTOR pathway, despite low plasma concentrations of nilotinib. Consequently, nilotinib-induced hypercholesterolaemia could not be predicted based on the plasma concentration of nilotinib.