The mean pharmacokinetic parameters for ceftazidime and avibactam in healthy adult male subjects with normal renal function after single and multiple 2-hour intravenous infusions of AVYCAZ 2.5 grams (ceftazidime 2 grams and avibactam 0.5 grams) administered every 8 hours are summarized in Table 12.
Pharmacokinetic parameters of ceftazidime and avibactam were similar for single and multiple dose administration of AVYCAZ and were similar to those determined when ceftazidime or avibactam were administered alone.
Table 12.
Pharmacokinetic Parameters (Geometric Mean [%CV]) of Ceftazidime and Avibactam Following Administration of AVYCAZ 2.5 grams (ceftazidime 2 grams and avibactam 0.5 grams) in Healthy Adult Male Subjects | Ceftazidime | Avibactam |
| Parameter | Single AVYCAZ 2.5 gramsa Dose Administered as a 2-hour Infusion (n = 16) | Multiple AVYCAZ 2.5 gramsa Doses Administered every 8 hours as 2-hour Infusions for 11 Days (n = 16) | Single AVYCAZ 2.5 gramsa Dose Administered as a 2-hour Infusion (n = 16) | Multiple AVYCAZ 2.5 gramsa Doses Administered every 8 hours as 2-hour Infusions for 11 Days (n = 16) |
| Cmax (mg/L) | 88.1 (14) | 90.4 (16) | 15.2 (14) | 14.6 (17) |
| AUC (mg-h/L)b | 289 (15)c | 291 (15) | 42.1 (16)d | 38.2 (19) |
| T1/2 (h) | 3.27 (33)c | 2.76 (7) | 2.22 (31)d | 2.71 (25) |
| CL (L/h) | 6.93 (15)c | 6.86 (15) | 11.9 (16)d | 13.1 (19) |
| Vss (L) | 18.1 (20)c | 17 (16) | 23.2 (23)d | 22.2 (18) |
CL = plasma clearance; Cmax = maximum observed concentration; T1/2 = terminal elimination half-life; Vss (L) = volume of distribution at steady state a
ceftazidime 2 grams and avibactam 0.5 grams b
AUC0-inf (area under concentration-time curve from time 0 to infinity) reported for single-dose administration; AUC0-tau (area under concentration curve over dosing interval) reported for multiple-dose administration c
n = 15 d
n = 13 |
The Cmax and AUC of ceftazidime increase in proportion to dose. Avibactam demonstrated approximately linear pharmacokinetics across the dose range studied (50 mg to 2000 mg) for single intravenous administration. No appreciable accumulation of ceftazidime or avibactam was observed following multiple intravenous infusions of AVYCAZ 2.5 grams (ceftazidime 2 grams and avibactam 0.5 grams) administered every 8 hours for up to 11 days in healthy adults with normal renal function.
Distribution
Less than 10% of ceftazidime was protein bound. The degree of protein binding was independent of concentration. The binding of avibactam to human plasma proteins was low (5.7% to 8.2%) and was similar across the range of concentrations tested in vitro (0.5 to 50 mg/L).
The steady-state volumes of distribution of ceftazidime and avibactam were 17 L and 22.2 L, respectively, in healthy adults following multiple doses of AVYCAZ 2.5 grams (ceftazidime 2 grams and avibactam 0.5 grams) infused every 8 hours over 2 hours for 11 days.
Following administration of AVYCAZ 2.5 g (ceftazidime 2 grams and avibactam 0.5 grams) to healthy male subjects every 8 hours as a 2-hour infusion for 3 days, the mean bronchial epithelial lining fluid-to-plasma ratios of avibactam Cmax and AUC0-tau were 35%. The mean bronchial epithelial lining fluid-to-plasma ratios of ceftazidime Cmax and AUC0-tau were 26% and 31%, respectively.
Metabolism
Ceftazidime is mostly (80% to 90% of the dose) eliminated as unchanged drug. No metabolism of avibactam was observed in human liver preparations (microsomes and hepatocytes). Unchanged avibactam was the major drug-related component in human plasma and urine after a single intravenous dose of 0.5 grams 14C-labelled avibactam.
Excretion
Both ceftazidime and avibactam are excreted mainly by the kidneys.
Approximately 80% to 90% of an intravenous dose of ceftazidime is excreted unchanged by the kidneys over a 24-hour period. After the intravenous administration of single 0.5-grams or 1-gram doses, approximately 50% of the dose appeared in the urine in the first 2 hours. An additional 20% was excreted between 2 and 4 hours after dosing, and approximately another 12% of the dose appeared in the urine between 4 and 8 hours later. The elimination of ceftazidime by the kidneys resulted in high therapeutic concentrations in the urine. The mean renal clearance of ceftazidime was approximately 100 mL/min. The calculated plasma clearance of approximately 115 mL/min indicated nearly complete elimination of ceftazidime by the renal route.
Following administration of a single 0.5-grams intravenous dose of radiolabeled avibactam, an average of 97% of administered radioactivity was recovered from the urine, with over 95% recovered within 12 hours of dosing. An average of 0.20% of administered total radioactivity was recovered in feces within 96 hours of dosing. An average of 85% of administered avibactam was recovered from the urine as unchanged drug within 96 hours, with over 50% recovered within 2 hours of the start of the infusion. Renal clearance was 158 mL/min, which is greater than the glomerular filtration, suggesting that active tubular secretion contributes to the excretion of avibactam in addition to glomerular filtration.
Specific Populations
Patients with Renal Impairment
Ceftazidime is eliminated almost solely by the kidneys; its serum half-life is significantly prolonged in patients with impaired renal function.
The clearance of avibactam was significantly decreased in subjects with mild (CrCl greater than 50 to 80 mL/min, n = 6), moderate (CrCl 30 to less than or equal to 50 mL/min, n = 6), and severe (CrCl 30 mL/min or less, not requiring hemodialysis; n = 6) renal impairment compared to healthy subjects with normal renal function (CrCl greater than 80 mL/min, n = 6) following administration of a single 100-mg intravenous dose of avibactam. The slower clearance resulted in increases in systemic exposure (AUC) of avibactam of 2.6-fold, 3.8-fold, and 7-fold in subjects with mild, moderate, and severe renal impairment, respectively, compared to subjects with normal renal function.
A single 100-mg dose of avibactam was administered to subjects with ESRD (n = 6) either 1 hour before or after hemodialysis. The avibactam AUC following the post-hemodialysis infusion was 19.5-fold the AUC of healthy subjects with normal renal function. Avibactam was extensively removed by hemodialysis, with an extraction coefficient of 0.77 and a mean hemodialysis clearance of 9.0 L/h. Approximately 55% of the avibactam dose was removed during a 4-hour hemodialysis session.
Dosage adjustment of AVYCAZ is recommended in patients with moderate and severe renal impairment and end-stage renal disease. Population PK models for ceftazidime and avibactam were used to conduct simulations for patients with impaired renal function. Simulations demonstrated that the recommended dose adjustments [see Dosage and Administration (2.2)] provide comparable exposures of ceftazidime and avibactam in patients with moderate and severe renal impairment and end-stage renal disease to those in patients with normal renal function or mild renal impairment. Because the exposure of both ceftazidime and avibactam is highly dependent on renal function, monitor CrCl at least daily and adjust the dosage of AVYCAZ accordingly for patients with changing renal function [see Dosage and Administration (2.2)].
Patients with Hepatic Impairment
The presence of hepatic dysfunction had no effect on the pharmacokinetics of ceftazidime in individuals administered 2 grams intravenously every 8 hours for 5 days.
The pharmacokinetics of avibactam in patients with hepatic impairment have not been established. Avibactam does not appear to undergo significant hepatic metabolism; therefore, the systemic clearance of avibactam is not expected to be significantly affected by hepatic impairment.
Dose adjustments are not currently considered necessary for AVYCAZ in patients with impaired hepatic function.
Geriatric Patients
Following single-dose administration of 0.5 grams avibactam as a 30-minute infusion the mean AUC for avibactam was 17% higher in healthy elderly subjects (65 years of age and older, n = 16) than in healthy young adult subjects (18 to 45 years of age, n = 17). There was no statistically significant age effect for avibactam Cmax.
No dose adjustment is recommended based on age. Dosage adjustment for AVYCAZ in elderly patients should be based on renal function [see Dosage and Administration (2.2)].
Gender
Following single-dose administration of 0.5 grams avibactam as a 30-minute infusion, healthy male subjects (n = 17) had 18% lower avibactam Cmax values than healthy female subjects (n = 16). There was no gender effect for avibactam AUC parameters.
No dose adjustment is recommended based on gender.
Drug Interactions
Avibactam at clinically relevant concentrations does not inhibit the cytochrome P450 isoforms CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4/5 in vitro in human liver microsomes. Avibactam showed no potential for in vitro induction of CYP1A2, 2B6, 2C9 and 3A4 isoenzymes in human hepatocytes. Against CYP2E1, avibactam showed a slight induction potential at very high concentrations that exceed any clinically relevant exposure. Ceftazidime was evaluated independently in human hepatocytes and showed no induction potential on the activity or mRNA expression of CYP1A1/2, CYP2B6, and CYP3A4/5.
Neither ceftazidime nor avibactam was found to be an inhibitor of the following hepatic and renal transporters in vitro at clinically relevant concentrations: MDR1, BCRP, OAT1, OAT3, OATP1B1, OATP1B3, BSEP, MRP4, OCT1 and OCT2. Avibactam was not a substrate of MDR1, BCRP, MRP4, or OCT2, but was a substrate of human OAT1 and OAT3 kidney transporters based on results generated in human embryonic kidney cells expressing these transporters. Probenecid inhibits 56% to 70% of the uptake of avibactam by OAT1 and OAT3 in vitro. Ceftazidime does not inhibit avibactam transport mediated by OAT1 and OAT3. The clinical impact of potent OAT inhibitors on the pharmacokinetics of avibactam is not known. Co-administration of AVYCAZ with probenecid is not recommended [see Drug Interactions (7.1)].
Administration of AVYCAZ 2.5 grams (ceftazidime 2 grams and avibactam 0.5 grams) to healthy male subjects (n = 28) as a 2-hour infusion following a 1-hour infusion of metronidazole every 8 hours for 3 days, did not affect the Cmax and AUC values for avibactam or ceftazidime compared to administration of AVYCAZ 2.5 grams (ceftazidime 2 grams and avibactam 0.5 grams) alone. Administration of 0.5 grams metronidazole to healthy male subjects as a 1-hour infusion before a 2-hour infusion of AVYCAZ 2.5 grams (ceftazidime 2 grams and avibactam 0.5 grams) every 8 hours for 3 days did not affect the Cmax and AUC of metronidazole compared to administration of 0.5 grams metronidazole alone.