title: Safety and pharmacokinetics of single and multiple ascending doses of avibactam alone and in combination with ceftazidime in healthy male volunteers: results of two randomized, placebo-controlled studies.
abstract: OBJECTIVE
  Avibactam is a novel non-β-lactam β-lactamase inhibitor effective against Ambler class A, C and some class D β-lactamases that is currently in clinical development in combination with ceftazidime for the treatment of serious Gram-negative infections. It restores the in vitro activity of a range of β-lactams, including ceftazidime, against extended-spectrum β-lactamase-producing pathogens. Two phase I studies assessed the safety and pharmacokinetics of avibactam in healthy subjects when administered alone or with ceftazidime.
  
  
  METHODS
  The first study (NXL104-1001) was a placebo-controlled, single-ascending dose study assessing avibactam 50, 100, 250, 500, 1000, 1500 or 2000 mg given as a 30-min intravenous infusion. After a 7-day washout, subjects in the 250 and 500 mg dosing groups received a second avibactam dose with concomitant ceftazidime 1000 or 2000 mg, respectively. The second study (NXL104-1002) was performed in two parts. Part 1 assessed multiple-ascending doses of avibactam. Subjects were randomized to receive avibactam 500, 750 or 1000 mg every 8 h (q8 h) over 5 days, or ceftazidime-avibactam 2000-500 mg q8 h over 10 days. Part 2 assessed bioavailability of avibactam after a single oral dose (500 mg) relative to a single 30-min intravenous infusion (500 mg).
  
  
  RESULTS
  No serious or severe adverse events were reported in either study. Avibactam exposure generally increased proportionally to dose and there was no trend for accumulation after multiple doses. Almost all avibactam was excreted largely unchanged in the urine within the first 6 h. Concomitant ceftazidime did not affect avibactam's safety and pharmacokinetic profile. Avibactam exposure after oral dosing was very low at 6.2 % of that observed after intravenous infusion.
  
  
  CONCLUSIONS
  Avibactam was generally well tolerated across all dosing regimens, when given alone or with ceftazidime. Avibactam exposure was dose related in both studies, and avibactam pharmacokinetics were linear and not affected by ceftazidime.
authors: Pharsight Consulting Services Europe, Regus Business Centre, 37-39 Avenue Ledru Rollin, CS11237, 75570, Paris Cedex 12, France, Henri.Merdjan@certara.com.
authors: Henri
authors: H
authors: Merdjan
authors: Manickam
authors: M
authors: Rangaraju
authors: Antoine
authors: A
authors: Tarral
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D053961:Azabicyclo Compounds / Q000008:administration & dosage / Q000009:adverse effects* / Q000493:pharmacokinetics*; D001682:Biological Availability; D002442:Ceftazidime / Q000009:adverse effects* / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004338:Drug Combinations; D064368:Healthy Volunteers; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D055815:Young Adult; D065093:beta-Lactamase Inhibitors
chemical_list: D000900:Anti-Bacterial Agents; D053961:Azabicyclo Compounds; D004338:Drug Combinations; C000595613:avibactam, ceftazidime drug combination; D065093:beta-Lactamase Inhibitors; C543519:avibactam; D002442:Ceftazidime