Daptomycin pharmacokinetics and safety following administration of escalating doses once daily to healthy subjects.
The purpose of this paper is to establish the pharmacokinetics and safety of escalating, once-daily doses of daptomycin, a novel lipopeptide antibiotic active against gram-positive pathogens, including those resistant to methicillin and vancomycin. This phase 1, multiple-dose, double-blind study involved 24 healthy subjects in three dose cohorts (4, 6, and 8 mg/kg of body weight) who were randomized to receive daptomycin or the control at a 3:1 ratio and administered the study medication by a 30-min intravenous infusion every 24 h for 7 to 14 days. Daptomycin pharmacokinetics was assessed by blood and urine sampling. Safety and tolerability were evaluated by monitoring adverse events (AEs) and laboratory parameters. Daptomycin pharmacokinetics was linear through 6 mg/kg, with a slight ( approximately 20%) nonlinearity in the area under the curve and trough concentration at the highest dose studied (8 mg/kg). The pharmacokinetic parameters measured on the median day of the study period, (day 7) were half-life ( approximately 9 h), volume of distribution ( approximately 0.1 liters/kg), systemic clearance ( approximately 8.2 ml/h/kg), and percentage of the drug excreted intact in urine from 0 to 24 h ( approximately 54%). Daptomycin protein binding (mean amount bound, 91.7%) was independent of the drug concentration. No gender effect was observed. All subjects who received daptomycin completed the study. The frequencies and distributions of treatment-emergent AEs were similar for the subjects who received daptomycin and the control subjects. There were no serious AEs and no pattern of dose-related events. The pharmacokinetics of once-daily administration of daptomycin was linear through 6 mg/kg. For all three doses, plasma daptomycin concentrations were consistent and predictable throughout the dosing interval. Daptomycin was well tolerated when it was administered once daily at a dose as high as 8 mg/kg for 14 days.
Dvorchik
Barry H
BH
Cubist Pharmaceuticals, Inc., Lexington, Massachusetts 02421, USA. bdvorchik@cubist.com
Brazier
David
D
DeBruin
Michael F
MF
Arbeit
Robert D
RD
D000328:Adult; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics*; D003402:Creatine Kinase / Q000097:blood; D017576:Daptomycin / Q000009:adverse effects / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male
D000900:Anti-Bacterial Agents; D003402:Creatine Kinase; D017576:Daptomycin