title: The plasma and cerebrospinal fluid pharmacokinetics of sorafenib after intravenous administration in non-human primates.
abstract: OBJECTIVE
  Sorafenib is a small molecule inhibitor of multiple signaling kinases thought to contribute to the pathogenesis of many tumors including brain tumors. Clinical trials with sorafenib in primary and metastatic brain tumors are ongoing. We evaluated the plasma and cerebrospinal fluid (CSF) pharmacokinetics (PK) of sorafenib after an intravenous (IV) dose in a non-human primate (NHP) model.
  
  
  METHODS
  7.3 mg/kg of sorafenib free base equivalent solubilized in 20% cyclodextrin was administered IV over 1 h to three adult rhesus monkeys. Serial paired plasma and CSF samples were collected over 24 h. Sorafenib was quantified with a validated HPLC/tandem mass spectrometry assay. PK parameters were estimated using non-compartmental methods. CSF penetration was calculated from the AUC(CSF) : AUC(plasma).
  
  
  RESULTS
  Peak plasma concentrations after IV dosing ranged from 3.4 to 7.6 μg/mL. The mean ± standard deviation (SD) area under the plasma concentration from 0 to 24 h was 28 ± 4.3 μg • h/mL, which is comparable to the exposure observed in humans at recommended doses. The mean ± SD clearance was 1.7 ± 0.5 mL/min/kg. The peak CSF concentrations ranged from 0.00045 to 0.00058 μg/mL. The mean ± SD area under the CSF concentration from 0 to 24h was 0.0048 ± 0.0016 μg•h/mL. The mean CSF penetration of sorafenib was 0.02% and 3.4% after correcting for plasma protein binding.
  
  
  CONCLUSIONS
  Sorafenib is well tolerated in NHP and measurable in CSF after an IV dose. The CSF penetration of sorafenib is limited relative to total and free drug exposure in plasma.
authors.affiliation: Pediatric Oncology Branch, Pharmacology and Experimental Therapeutics Section, National Cancer Institute, 10 Center Drive, Building 10-CRC, Bethesda, MD 20892, USA. aekim@cnmc.org
authors.forename: AeRang
authors.initials: A
authors.lastname: Kim
authors.forename: Cindy
authors.initials: C
authors.lastname: McCully
authors.forename: Rafael
authors.initials: R
authors.lastname: Cruz
authors.forename: Diane E
authors.initials: DE
authors.lastname: Cole
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Fox
authors.forename: Frank M
authors.initials: FM
authors.lastname: Balis
authors.forename: Brigitte C
authors.initials: BC
authors.lastname: Widemann
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000097:blood / Q000134:cerebrospinal fluid / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001557:Benzenesulfonates / Q000008:administration & dosage* / Q000097:blood / Q000134:cerebrospinal fluid / Q000493:pharmacokinetics*; D001812:Blood-Brain Barrier / Q000378:metabolism; D002199:Capillary Permeability; D002851:Chromatography, High Pressure Liquid; D006207:Half-Life; D007262:Infusions, Intravenous; D008253:Macaca mulatta; D008297:Male; D008657:Metabolic Clearance Rate; D023421:Models, Animal; D008954:Models, Biological; D009536:Niacinamide / Q000031:analogs & derivatives; D010671:Phenylurea Compounds; D011485:Protein Binding; D047428:Protein Kinase Inhibitors / Q000008:administration & dosage* / Q000097:blood / Q000134:cerebrospinal fluid / Q000493:pharmacokinetics*; D011725:Pyridines / Q000008:administration & dosage* / Q000097:blood / Q000134:cerebrospinal fluid / Q000493:pharmacokinetics*; D000077157:Sorafenib; D053719:Tandem Mass Spectrometry
chemical_list: D000970:Antineoplastic Agents; D001557:Benzenesulfonates; D010671:Phenylurea Compounds; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D009536:Niacinamide; D000077157:Sorafenib