<p>Ceritinib is a kinase inhibitor. Targets of Ceritinib inhibition identified in either biochemical or cellular assays at clinically relevant concentrations include ALK, insulin- like growth factor 1 receptor (IGF-1R), insulin receptor (InsR), and ROS1. Among these, Ceritinib is most active against ALK. Ceritinib inhibited autophosphorylation of ALK, ALK-mediated phosphorylation of the downstream signaling protein STAT3, and proliferation of ALK dependent cancer cells in in vitro and in vivo assays.<br />
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<strong>Absorption</strong>: After a single oral administration of Ceritinib in patients, peak plasma levels (Cmax) of Ceritinib were achieved at approximately 4 to 6 hours, and AUC and C max increased dose proportionally over 50 to 750 mg under fasted conditions. The absolute bioavailability of Ceritinib has not been determined.<br />
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<strong>Distribution</strong>: Ceritinib is 97% bound to human plasma proteins, independent of drug concentration. The apparent volume of distribution is 4230 L following a single 750 mg fasted Ceritinib dose in patients. Ceritinib also has a slight preferential distribution to red blood cells, relative to plasma, with a mean in vitro blood-to-plasma ratio of 1.35.<br />
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<strong>Elimination</strong>: Following a single 750 mg fasted Ceritinib dose, the geometric mean apparent plasma terminal half life (t&frac12;) of Ceritinib was 41 hours in patients. Ceritinib demonstrates nonlinear PK over time. The geometric mean apparent clearance of Ceritinib was lower at steady-state (33.2 L/h) after 750 mg daily dosing than after a single 750 mg dose (88.5 L/h).<br />
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<strong>Metabolism</strong>: In vitro studies demonstrated that CYP3A was the major enzyme involved in the metabolic clearance of Ceritinib. Following oral administration of a single 750 mg radiolabeled Ceritinib dose under fasted conditions, Ceritinib as the parent compound was the main circulating component (82%) in human plasma.<br />
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<strong>Excretion</strong>: Following oral administration of a single 750 mg radiolabeled Ceritinib dose under fasted conditions, 92.3% of the administered dose was recovered in the feces (with 68% as unchanged parent compound) while 1.3% of the administered dose was recovered in the urine.</p>