title: Phase I study of cabazitaxel plus cisplatin in patients with advanced solid tumors: study to evaluate the impact of cytochrome P450 3A inhibitors (aprepitant, ketoconazole) or inducers (rifampin) on the pharmacokinetics of cabazitaxel.
abstract: OBJECTIVE
  Cabazitaxel is primarily metabolized by CYP3A. This study evaluated the impact of moderate/strong CYP3A inhibitors [aprepitant (Study Part 2); ketoconazole (Study Part 3)] or strong CYP3A inducers [rifampin (Study Part 4)] on the pharmacokinetics of cabazitaxel.
  
  
  METHODS
  Adult patients received IV cabazitaxel/cisplatin 15/75 mg/m(2) on Day 1 of 3-week cycles (5/75 mg/m(2) in Cycles 1 and 2 of Part 3 to allow a safety margin to the cabazitaxel MTD). Patients received repeated oral doses of aprepitant, ketoconazole or rifampin before/during Cycle 2. Cabazitaxel clearance was the primary endpoint; clearance and area under the plasma concentration-time curve (AUC) were normalized to body surface area and dose, respectively.
  
  
  RESULTS
  The PK population included 13 (Part 2), 23 (Part 3) and 21 patients (Part 4). Repeated aprepitant administration did not affect cabazitaxel clearance [geometric mean ratio (GMR) 0.98; 90 % confidence interval (CI) 0.80-1.19]. Repeated ketoconazole administration resulted in 20 % decrease in cabazitaxel clearance (GMR 0.80; 90 % CI 0.55-1.15), associated with 25 % increase in AUC (GMR 1.25; 90 % CI 0.86-1.81). Repeated rifampin administration resulted in 21 % increase in cabazitaxel clearance (GMR 1.21; 90 % CI 0.95-1.53), associated with 17 % decrease in AUC (GMR 0.83; 90 % CI 0.65-1.05). The GMR of AUC0-24 with rifampin administration was 1.09 (90 % CI 0.9-1.33), suggesting that rifampin had a low impact during the initial phases of cabazitaxel elimination. Safety findings were consistent with previous results.
  
  
  CONCLUSIONS
  Cabazitaxel pharmacokinetics are modified by drugs strongly affecting CYP3A. Co-administration of cabazitaxel with strong CYP3A inhibitors or inducers should be avoided.
authors.affiliation: Institute for Drug Development, Cancer Therapy and Research Center at UTHSCSA, University of Texas Health Science Center San Antonio, 4th Floor, Zeller Building, 7979 Wurzbach Road, San Antonio, TX, 78229, USA, sarantopoulo@uthscsa.edu.
authors.forename: John
authors.initials: J
authors.lastname: Sarantopoulos
authors.forename: Alain C
authors.initials: AC
authors.lastname: Mita
authors.forename: James L
authors.initials: JL
authors.lastname: Wade
authors.forename: John C
authors.initials: JC
authors.lastname: Morris
authors.forename: Olivier
authors.initials: O
authors.lastname: Rixe
authors.forename: Monica M
authors.initials: MM
authors.lastname: Mita
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Dedieu
authors.forename: Claudine
authors.initials: C
authors.lastname: Wack
authors.forename: Laurent
authors.initials: L
authors.lastname: Kassalow
authors.forename: A Craig
authors.initials: AC
authors.lastname: Lockhart
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000627:therapeutic use; D000077608:Aprepitant; D019540:Area Under Curve; D002945:Cisplatin / Q000008:administration & dosage; D051544:Cytochrome P-450 CYP3A / Q000187:drug effects* / Q000378:metabolism; D065692:Cytochrome P-450 CYP3A Inhibitors / Q000494:pharmacology*; D065693:Cytochrome P-450 Enzyme Inducers / Q000494:pharmacology*; D004347:Drug Interactions; D005260:Female; D006801:Humans; D007654:Ketoconazole / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009025:Morpholines / Q000494:pharmacology; D009369:Neoplasms / Q000188:drug therapy / Q000473:pathology; D012293:Rifampin / Q000494:pharmacology; D043823:Taxoids / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D065692:Cytochrome P-450 CYP3A Inhibitors; D065693:Cytochrome P-450 Enzyme Inducers; D009025:Morpholines; D043823:Taxoids; D000077608:Aprepitant; C552428:cabazitaxel; D051544:Cytochrome P-450 CYP3A; D002945:Cisplatin; D007654:Ketoconazole; D012293:Rifampin