CLINICAL PHARMACOLOGY
Mechanism Of Action
AVELOX is a member of the fluoroquinolone class of
antibacterial agents [see Microbiology].
Pharmacodynamics
Photosensitivity Potential
A study of the skin response to ultraviolet (UVA and UVB)
and visible radiation conducted in 32 healthy volunteers (8 per group)
demonstrated that AVELOX does not show phototoxicity in comparison to placebo.
The minimum erythematous dose (MED) was measured before and after treatment
with AVELOX (200 mg or 400 mg once daily), lomefloxacin (400 mg once daily), or
placebo. In this study, the MED measured for both doses of AVELOX were not
significantly different from placebo, while lomefloxacin significantly lowered
the MED [see WARNINGS AND PRECAUTIONS].
Pharmacokinetics
Absorption
Moxifloxacin, given as an oral tablet, is well absorbed
from the gastrointestinal tract. The absolute bioavailability of moxifloxacin
is approximately 90 percent. Co-administration with a high fat meal (that is,
500 calories from fat) does not affect the absorption of moxifloxacin.
Consumption of 1 cup of yogurt with moxifloxacin does not
affect the rate or extent of the systemic absorption (that is, area under the
plasma concentration time curve (AUC).
Table 5: Mean (± SD) Cmax and AUC values following single
and multiple doses of 400 mg moxifloxacin given orally
|
Cmax (mg/L) |
AUC (mg•h/L) |
Half-life (hr) |
Single Dose Oral Healthy (n = 372) |
3.1 ± 1 |
36.1 ± 9.1 |
11.5-15.6a |
Multiple Dose Oral |
|
|
|
Healthy young male/female (n = 15) |
4.5 ± 0.5 |
48 ± 2.7 |
12.7 ± 1.9 |
Healthy elderly male (n = 8) |
3.8 ± 0.3 |
51.8 ± 6.7 |
|
Healthy elderly female (n = 8) |
4.6 ± 0.6 |
54.6 ± 6.7 |
|
Healthy young male (n = 8) |
3.6 ± 0.5 |
48.2 ± 9 |
|
Healthy young female (n = 9) |
4.2 ± 0.5 |
49.3 ± 9.5 |
|
aRange of means from different studies |
Table 6: Mean (± SD) Cmax and AUC values following
single and multiple doses of 400 mg moxifloxacin given by 1-hour intravenous
infusion
|
Cmax (mg/L) |
AUC (mg•h/L) |
Half-life (hour) |
Single Dose intravenous |
Healthy young male/female (n = 56) |
3.9 ± 0.9 |
39.3 ± 8.6 |
8.2-15.4a |
Patients (n = 118) |
|
|
|
Male (n = 64) |
4.4 ± 3.7 |
|
|
Female (n = 54) |
4.5 ± 2 |
|
|
< 65 years (n = 58) |
4.6 ± 4.2 |
|
|
≥ 65 years (n = 60) |
4.3 ± 1.3 |
|
|
Multiple Dose intravenous |
|
|
|
Healthy young male (n = 8) |
4.2 ± 0.8 |
38 ± 4.7 |
14.8 ± 2.2 |
Healthy elderly (n =12; 8 male, 4 female) |
6.1 ± 1.3 |
48.2 ± 0.9 |
10.1 ± 1.6 |
Patientsb (n = 107) |
|
|
|
Male (n = 58) |
4.2 ± 2.6 |
|
|
Female (n = 49) |
4.6 ± 1.5 |
|
|
< 65 years (n = 52) |
4.1 ± 1.4 |
|
|
≥ 65 years (n = 55) |
4.7 ± 2.7 |
|
|
aRange of means from different studies
bExpected Cmax (concentration obtained around the time of the end of
the infusion) |
Plasma concentrations increase proportionately with dose
up to the highest dose tested (1200 mg single oral dose). The mean (± SD)
elimination half-life from plasma is 12 ± 1.3 hours; steady-state is achieved after
at least three days with a 400 mg once daily regimen.
Mean Steady-State Plasma Concentrations of
Moxifloxacin Obtained With Once Daily Dosing of 400 mg Either Orally (n=10) or
by Intravenous Infusion (n=12)
Distribution
Moxifloxacin is approximately 30-50% bound to serum
proteins, independent of drug concentration. The volume of distribution of
moxifloxacin ranges from 1.7 to 2.7 L/kg. Moxifloxacin is widely distributed
throughout the body, with tissue concentrations often exceeding plasma
concentrations. Moxifloxacin has been detected in the saliva, nasal and
bronchial secretions, mucosa of the sinuses, skin blister fluid, subcutaneous
tissue, skeletal muscle, and abdominal tissues and fluids following oral or intravenous
administration of 400 mg. Moxifloxacin concentrations measured post-dose in
various tissues and fluids following a 400 mg oral or intravenous dose are summarized
in Table 7. The rates of elimination of moxifloxacin from tissues generally
parallel the elimination from plasma.
Table 7: Moxifloxacin Concentrations (mean ± SD) in
Tissues and the Corresponding Plasma  Concentrations After a Single 400 mg Oral
or Intravenous Dosea
Tissue or Fluid |
N |
Plasma Concentration (mcg/mL) |
Tissue or Fluid Concentration (mcg/mL or mcg/g) |
Tissue Plasma Ratio |
Respiratory |
Alveolar Macrophages |
5 |
3.3 ± 0.7 |
61.8 ± 27.3 |
21.2 ± 10 |
Bronchial Mucosa |
8 |
3.3 ± 0.7 |
5.5 ± 1.3 |
1.7 ± 0.3 |
Epithelial Lining Fluid |
5 |
3.3 ± 0.7 |
24.4 ± 14.7 |
8.7 ± 6.1 |
Sinus |
Maxillary Sinus Mucosa |
4 |
3.7 ± 1.1b |
7.6 ± 1.7 |
2 ± 0.3 |
Anterior Ethmoid Mucosa |
3 |
3.7 ± 1.1b |
8.8 ± 4.3 |
2.2 ± 0.6 |
Nasal Polyps |
4 |
3.7 ± 1.1b |
9.8 ± 4.5 |
2.6 ± 0.6 |
Skin, Musculoskeletal |
Blister Fluid |
5 |
3 ± 0.5c |
2.6 ± 0.9 |
0.9 ± 0.2 |
Subcutaneous Tissue |
6 |
2.3 ± 0.4d |
0.9 ± 0.3e |
0.4 ± 0.6 |
Skeletal Muscle |
6 |
2.3 ± 0.4d |
0.9 ± 0.2e |
0.4 ± 0.1 |
Intra-Abdominal |
Abdominal tissue |
8 |
2.9 ± 0.5 |
7.6 ± 2 |
2.7 ± 0.8 |
Abdominal exudate |
10 |
2.3 ± 0.5 |
3.5 ±1.2 |
1.6 ± 0.7 |
Abscess fluid |
6 |
2.7 ± 0.7 |
2.3 ±1.5 |
0.8 ± 0.4 |
aAll moxifloxacin concentrations were measured
3 hours after a single 400 mg dose, except the abdominal tissue and exudate
concentrations which were measured at 2 hours post-dose and the sinus
concentrations which were measured 3 hours post-dose after 5 days of dosing.
bN = 5
cN = 7
dN = 12
eReflects only non-protein bound concentrations of drug. |
Metabolism
Approximately 52% of an oral or intravenous dose of
moxifloxacin is metabolized via glucuronide and sulfate conjugation. The cytochrome
P450 system is not involved in moxifloxacin metabolism, and is not affected by
moxifloxacin. The sulfate conjugate (M1) accounts for approximately 38% of the
dose, and is eliminated primarily in the feces. Approximately 14% of an oral or
intravenous dose is converted to a glucuronide conjugate (M2), which is
excreted exclusively in the urine. Peak plasma concentrations of M2 are
approximately 40% those of the parent drug, while plasma concentrations of M1
are generally less than 10% those of moxifloxacin.
In vitro studies with cytochrome (CYP) P450 enzymes
indicate that moxifloxacin does not inhibit CYP3A4, CYP2D6, CYP2C9, CYP2C19, or
CYP1A2.
Excretion
Approximately 45% of an oral or intravenous dose of
moxifloxacin is excreted as unchanged drug (~20% in urine and ~25% in feces). A
total of 96% ± 4% of an oral dose is excreted as either unchanged drug or known
metabolites. The mean (± SD) apparent total body clearance and renal clearance
are 12 ± 2 L/hr and 2.6 ± 0.5 L/hr, respectively.
Pharmacokinetics In Specific Populations
Geriatric
Following oral administration of 400 mg moxifloxacin for
10 days in 16 elderly (8 male; 8 female) and 17 young (8 male; 9 female)
healthy volunteers, there were no age-related changes in
moxifloxacinpharmacokinetics. In 16 healthy male volunteers (8 young; 8
elderly) given a single 200 mg dose of oral moxifloxacin, the extent of
systemic exposure (AUC and Cmax) was not statistically different between young
and elderly males and elimination half-life was unchanged. No dosage adjustment
is necessary based on age. In large phase III studies, the concentrations
around the time of the end of the infusion in elderly patients following
intravenous infusion of 400 mg were similar to those observed in young patients
[see Use in Specific Populations].
Pediatric
The pharmacokinetics of moxifloxacin in pediatric
subjects has not been studied [see Use in Specific Populations].
Gender
Following oral administration of 400 mg moxifloxacin
daily for 10 days to 23 healthy males (19-75 years) and 24 healthy females
(19-70 years), the mean AUC and Cmax were 8% and 16% higher, respectively, in
females compared to males. There are no significant differences in moxifloxacin
pharmacokinetics between male and female subjects when differences in body
weight are taken into consideration.
A 400 mg single dose study was conducted in 18 young
males and females. The comparison of moxifloxacin pharmacokinetics in this study (9 young females and 9 young males) showed no differences in AUC or Cmax due to gender. Dosage adjustments based on gender are not necessary.
Race
Steady-state moxifloxacin pharmacokinetics in male
Japanese subjects were similar to those determined in Caucasians, with a mean
Cmax of 4.1 mcg/mL, an AUC24 of 47 mcg•h/mL, and an elimination half-life of 14
hours, following 400 mg p.o. daily.
Renal Insufficiency
The pharmacokinetic parameters of moxifloxacin are not
significantly altered in mild, moderate, severe, or end-stage renal disease. No
dosage adjustment is necessary in patients with renal impairment, including
those patients requiring hemodialysis (HD) or continuous ambulatory peritoneal
dialysis (CAPD).
In a single oral dose study of 24 patients with varying
degrees of renal function from normal to severely impaired, the mean peak concentrations
(Cmax) of moxifloxacin were reduced by 21% and 28% in the patients with moderate
(CLCR ≥ 30 and ≤ 60 mL/min) and severe (CLCR < 30 mL/min) renal
impairment, respectively. The mean systemic exposure (AUC) in these patients
was increased by 13%. In the moderate and severe renally impaired patients, the
mean AUC for the sulfate conjugate (M1) increased by 1.7-fold (ranging up to
2.8-fold) and mean AUC and Cmax for the glucuronide conjugate (M2) increased by
2.8-fold (ranging up to 4.8-fold) and 1.4-fold (ranging up to 2.5-fold),
respectively [see Use in Specific Populations].
The pharmacokinetics of single dose and multiple dose
moxifloxacin were studied in patients with CLCR < 20 mL/min on either
hemodialysis or continuous ambulatory peritoneal dialysis (8 HD, 8 CAPD).
Following a single 400 mg oral dose, the AUC of moxifloxacin in these HD and
CAPD patients did not vary significantly from the AUC generally found in
healthy volunteers. Cmax values of moxifloxacin were reduced by about 45% and
33% in HD and CAPD patients, respectively, compared to healthy, historical
controls. The exposure (AUC) to the sulfate conjugate (M1) increased by 1.4- to
1.5-fold in these patients. The mean AUC of the glucuronide conjugate (M2)
increased by a factor of 7.5, whereas the mean Cmax values of the glucuronide
conjugate (M2) increased by a factor of 2.5 to 3, compared to healthy subjects.
The sulfate and the glucuronide conjugates of moxifloxacin are not microbiologically
active, and the clinical implication of increased exposure to these metabolites
in patients with renal disease including those undergoing HD and CAPD has not
been studied.
Oral administration of 400 mg QD AVELOX for 7 days to
patients on HD or CAPD produced mean systemic exposure (AUCss) to moxifloxacin
similar to that generally seen in healthy volunteers. Steadystate Cmax values
were about 22% lower in HD patients but were comparable between CAPD patients and
healthy volunteers. Both HD and CAPD removed only small amounts of moxifloxacin
from the body (approximately 9% by HD, and 3% by CAPD). HD and CAPD also
removed about 4% and 2% of the glucuronide metabolite (M2), respectively.
Hepatic Insufficiency
No dosage adjustment is recommended for mild, moderate,
or severe hepatic insufficiency (Child-Pugh Classes A, B, or C). However, due
to metabolic disturbances associated with hepatic insufficiency, which may lead
to QT prolongation, AVELOX should be used with caution in these patients [see WARNINGS
AND PRECAUTIONS and Use in Specific Populations].
In 400 mg single oral dose studies in 6 patients with
mild (Child-Pugh Class A) and 10 patients with moderate (Child-Pugh Class B)
hepatic insufficiency, moxifloxacin mean systemic exposure (AUC) was 78% and
102%, respectively, of 18 healthy controls and mean peak concentration (Cmax)
was 79% and 84% of controls.
The mean AUC of the sulfate conjugate of moxifloxacin
(M1) increased by 3.9-fold (ranging up to 5.9- fold) and 5.7-fold (ranging up
to 8-fold) in the mild and moderate groups, respectively. The mean Cmax of M1
increased by approximately 3-fold in both groups (ranging up to 4.7- and
3.9-fold). The mean AUC of the glucuronide conjugate of moxifloxacin (M2)
increased by 1.5-fold (ranging up to 2.5-fold) in both groups. The mean Cmax of
M2 increased by 1.6- and 1.3-fold (ranging up to 2.7- and 2.1-fold), respectively.
The clinical significance of increased exposure to the sulfate and glucuronide
conjugates has not been studied. In a subset of patients participating in a
clinical trial, the plasma concentrations of moxifloxacin and metabolites
determined approximately at the moxifloxacin Tmax following the first intravenous
or oral AVELOX dose in the Child-Pugh Class Cmax patients (n=10) were similar
to those in the Child-Pugh Class A/B patients (n=5), and also similar to those
observed in healthy volunteer studies.
Drug-Drug Interactions
The following drug interactions were studied in healthy
volunteers or patients.
Antacids and iron significantly reduced bioavailability
of moxifloxacin, as observed with other fluoroquinolones [see DRUG
INTERACTIONS].
Calcium, digoxin, itraconazole, morphine, probenecid,
ranitidine, theophylline, cyclosporine and warfarin did not significantly
affect the pharmacokinetics of moxifloxacin. These results and the data from in
vitro studies suggest that moxifloxacin is unlikely to significantly alter the
metabolic clearance of drugs metabolized by CYP3A4, CYP2D6, CYP2C9, CYP2C19, or
CYP1A2 enzymes.
Moxifloxacin had no clinically significant effect on the
pharmacokinetics of atenolol, digoxin, glyburide, itraconazole, oral
contraceptives, theophylline, cyclosporine and warfarin. However, fluoroquinolones,
including AVELOX, have been reported to enhance the anticoagulant effects of warfarin
or its derivatives in the patient population [see DRUG INTERACTIONS].
Antacids
When moxifloxacin (single 400 mg tablet dose) was
administered two hours before, concomitantly, or 4 hours after an
aluminum/magnesium-containing antacid (900 mg aluminum hydroxide and 600 mg magnesium
hydroxide as a single oral dose) to 12 healthy volunteers there was a 26%, 60%
and 23% reduction in the mean AUC of moxifloxacin, respectively. Moxifloxacin
should be taken at least 4 hours before or 8 hours after antacids containing
magnesium or aluminum, as well as sucralfate, metal cations such as iron, and
multivitamin preparations with zinc, or didanosine buffered tablets for oral
suspension or the pediatric powder for oral solution [see DOSAGE AND
ADMINISTRATION and DRUG INTERACTIONS].
Atenolol
In a crossover study involving 24 healthy volunteers (12
male; 12 female), the mean atenolol AUC following a single oral dose of 50 mg
atenolol with placebo was similar to that observed when atenolol was given
concomitantly with a single 400 mg oral dose of moxifloxacin. The mean Cmax of
single dose atenolol decreased by about 10% following co-administration with a
single dose of moxifloxacin.
Calcium
Twelve healthy volunteers were administered concomitant
moxifloxacin (single 400 mg dose) and calcium (single dose of 500 mg Ca++
dietary supplement) followed by an additional two doses of calcium 12 and 24
hours after moxifloxacin administration. Calcium had no significant effect on
the mean AUC of moxifloxacin. The mean Cmax was slightly reduced and the time
to maximum plasma concentration was prolonged when moxifloxacin was given with
calcium compared to when moxifloxacin was given alone (2.5 hours versus 0.9
hours). These differences are not considered to be clinically significant.
Digoxin
No significant effect of moxifloxacin (400 mg once daily
for two days) on digoxin (0.6 mg as a single dose) AUC was detected in a study
involving 12 healthy volunteers. The mean digoxin Cmax increased by about 50%
during the distribution phase of digoxin. This transient increase in digoxin
Cmax is not viewed to be clinically significant. Moxifloxacin pharmacokinetics
were similar in the presence or absence of digoxin. No dosage adjustment for
moxifloxacin or digoxin is required when these drugs are administered
concomitantly.
Glyburide
In diabetics, glyburide (2.5 mg once daily for two weeks
pretreatment and for five days concurrently) mean AUC and Cmax were 12% and 21%
lower, respectively, when taken with moxifloxacin (400 mg once daily for five
days) in comparison to placebo. Nonetheless, blood glucose levels were
decreased slightly in patients taking glyburide and moxifloxacin in comparison
to those taking glyburide alone, suggesting no interference by moxifloxacin on
the activity of glyburide. These interaction results are not viewed as
clinically significant.
Iron
When moxifloxacin tablets were administered concomitantly
with iron (ferrous sulfate 100 mg once
daily for two days), the mean AUC and Cmax of
moxifloxacin was reduced by 39% and 59%, respectively. Moxifloxacin should only
be taken more than 4 hours before or 8 hours after iron products [see DOSAGE
AND ADMINISTRATION and DRUG INTERACTIONS].
Itraconazole
In a study involving 11 healthy volunteers, there was no
significant effect of itraconazole (200 mg once daily for 9 days), a potent
inhibitor of cytochrome P4503A4, on the pharmacokinetics of moxifloxacin (a
single 400 mg dose given on the 7 day of itraconazole dosing). In addition,
moxifloxacin was shown not to affect the pharmacokinetics of itraconazole.
Morphine
No significant effect of morphine sulfate (a single 10 mg
intramuscular dose) on the mean AUC and Cmax of moxifloxacin (400 mg single
dose) was observed in a study of 20 healthy male and female volunteers.
Oral Contraceptives
A placebo-controlled study in 29 healthy female subjects
showed that moxifloxacin 400 mg daily for 7 days did not interfere with the hormonal
suppression of oral contraception with 0.15 mg levonorgestrel/0.03 mg
ethinylestradiol (as measured by serum progesterone, FSH, estradiol, and LH), or
with the pharmacokinetics of the administered contraceptive agents.
Probenecid
Probenecid (500 mg twice daily for two days) did not
alter the renal clearance and total amount of moxifloxacin (400 mg single dose)
excreted renally in a study of 12 healthy volunteers.
Ranitidine
No significant effect of ranitidine (150 mg twice daily
for three days as pretreatment) on the pharmacokinetics of moxifloxacin (400 mg
single dose) was detected in a study involving 10 healthy volunteers.
Theophylline
No significant effect of moxifloxacin (200 mg every
twelve hours for 3 days) on the pharmacokinetics of theophylline (400 mg every
twelve hours for 3 days) was detected in a study involving 12 healthy volunteers.
In addition, theophylline was not shown to affect the pharmacokinetics of
moxifloxacin. The effect of co-administration of 400 mg once daily of
moxifloxacin with theophylline has not been studied.
Warfarin
No significant effect of moxifloxacin (400 mg once daily
for eight days) on the pharmacokinetics of Rand S-warfarin (25 mg single dose
of warfarin sodium on the fifth day) was detected in a study involving 24
healthy volunteers. No significant change in prothrombin time was observed.
However, fluoroquinolones, including AVELOX, have been reported to enhance the
anticoagulant effects of warfarin or its derivatives in the patient population [see
ADVERSE REACTIONS and DRUG INTERACTIONS].
Microbiology
Mechanism Of Action
The bactericidal action of moxifloxacin results from
inhibition of the topoisomerase II (DNA gyrase) and topoisomerase IV required
for bacterial DNA replication, transcription, repair, and recombination.
Mechanism Of Resistance
The mechanism of action for fluoroquinolones, including
moxifloxacin, is different from that of macrolides, beta-lactams,
aminoglycosides, or tetracyclines; therefore, microorganisms resistant to these
classes of drugs may be susceptible to moxifloxacin. Resistance to
fluoroquinolones occurs primarily by a mutation in topoisomerase II (DNA
gyrase) or topoisomerase IV genes, decreased outer membrane permeability or
drug efflux. In vitro resistance to moxifloxacin develops slowly via
multiplestep mutations. Resistance to moxifloxacin occurs in vitro at a general
frequency of between 1.8 x 10-9 to < 1 x 10-11 for
Gram-positive bacteria.
Cross Resistance
Cross-resistance has been observed between moxifloxacin
and other fluoroquinolones against Gramnegative bacteria. Gram-positive
bacteria resistant to other fluoroquinolones may, however, still be susceptible
to moxifloxacin. There is no known cross-resistance between moxifloxacin and
other classes of antimicrobials.
Moxifloxacin has been shown to be active against most
isolates of the following bacteria, both in vitro and in clinical infections [see
INDICATIONS AND USAGE].
Gram-positive Bacteria
Enterococcus faecalis
Staphylococcus aureus
Streptococcus anginosus
Streptococcus constellatus
Streptococcus pneumoniae (including multi-drug
resistant isolates [MDRSP] **)
Streptococcus pyogenes
**MDRSP, Multi-drug resistant Streptococcus pneumoniae includes
isolates previously known as PRSP (Penicillin-resistant S. pneumoniae), and are
isolates resistant to two or more of the following antibiotics: penicillin
(MIC) ≥ 2 mcg/mL), 2nd generation cephalosporins (for example,
cefuroxime), macrolides, tetracyclines, and trimethoprim/sulfamethoxazole.
Gram-negative Bacteria
Enterobacter cloacae
Escherichia coli
Haemophilus influenzae
Haemophilus parainfluenzae
Klebsiella pneumoniae
Moraxella catarrhalis
Proteus mirabilis
Yersinia pestis
Anaerobic bacteria
Bacteroides fragilis
Bacteroides thetaiotaomicron
Clostridium perfringens
Peptostreptococcus species
Other microorganisms
Chlamydophila pneumoniae
Mycoplasma pneumoniae
The following in vitro data are available, but their
clinical significance is unknown.At least 90 percent of the following bacteria
exhibit an in vitro minimum inhibitory concentration (MIC) less than or equal
to the susceptible breakpoint for moxifloxacin. However, the efficacy of AVELOX
in treating clinical infections due to these bacteria has not beenestablished
in adequate and well controlled clinical trials.
Gram-positive Bacteria
Staphylococcus epidermidis
Streptococcus agalactiae
Streptococcus viridans group
Gram-negative Bacteria
Citrobacter freundii
Klebsiella oxytoca
Legionella pneumophila
Anaerobic bacteria
Fusobacterium species
Prevotella species
Susceptibility Tests Methods
When available, the clinical microbiology laboratory
should provide the results of in vitro susceptibility test results for
antimicrobial drug products used in resident hospitals to the physician as periodic
reports that describe the susceptibility profile of nosocomial and community
acquired pathogens. These reports should aid the physician in selecting an
antibacterial drug product for treatment.
Dilution Techniques
Quantitative methods are used to determine antimicrobial
minimum inhibitory concentrations (MICs). These MICs provide estimates of the
susceptibility of bacteria to antimicrobial compounds. The MICs should be
determined using a standardized procedure. Standardized procedures are based on
a dilution method (broth and/or agar).1,2,4 The MIC values should be
interpreted according to the criteria in Table 8.
Diffusion Techniques
Quantitative methods that require measurement of zone
diameters can also provide reproducible estimates of the susceptibility of
bacteria to antimicrobial compounds. The zone size provides an estimate of the
susceptibility of bacteria to antimicrobial compounds. The zone size prove
should be determined using a standardized test method.2,3 This
procedure uses paper disks impregnated with 5 mcg moxifloxacin to test the
susceptibility of bacteria to moxifloxacin. The disc diffusion interpretive criteria
are provided in Table 8.
Anaerobic Techniques
For anaerobic bacteria, the susceptibility to
moxifloxacin can be determined by a standardized test method.2,5 The
MIC values obtained should be interpreted according to the criteria provided in
Table 8.
Table 8: Susceptibility Test Interpretive Criteria for
Moxifloxacin
Species |
MIC (mcg/mL) |
Zone Diameter (mm) |
S |
I |
R |
S |
I |
R |
Enterobacteriaceae |
≤ 2 |
4 |
≥ 8 |
≥ 19 |
16-18 |
≤ 15 |
Enterococcus faecalis |
≤ 1 |
2 |
≥ 4 |
≥ 18 |
15-17 |
≤ 14 |
Staphylococcus aureus |
≤ 2 |
4 |
≥ 8 |
≥ 19 |
16-18 |
≤ 15 |
Haemophilus influenzae |
≤ 1 |
a |
a |
≥ 18 |
a |
a |
Haemophilus parainfluenzae |
≤ 1 |
a |
a |
≥ 18 |
a |
a |
Streptococcus pneumoniae |
≤ 1 |
2 |
≥ 4 |
≥ 18 |
15-17 |
≤ 14 |
Streptococcus species |
≤ 1 |
2 |
≥ 4 |
≥ 18 |
15-17 |
≤ 14 |
Anaerobic bacteria |
≤ 2 |
4 |
≥ 8 |
- |
- |
- |
Yersinia pestis |
≤ 0.25 |
a |
a |
- |
- |
- |
S=susceptible, I=Intermediate, and R=resistant.
a The current absence of data on moxifloxacin-resistant isolates
precludes defining any results other than “Susceptible”. Isolates yielding test
results (MIC or zone diameter) other than susceptible, should be submitted to a
reference laboratory for additional testing. |
A report of “Susceptible” indicates that the antimicrobial
is likely to inhibit growth of the pathogen if the antimicrobial compound
reaches the concentrations at the infection site necessary to inhibit growth of
the pathogen. A report of “Intermediate” indicates that the result should be
considered equivocal, and, if the microorganism is not fully susceptible to
alternative, clinically feasible drugs, the test should be repeated. This
category implies possible clinical applicability in body sites where the drug
is physiologically concentrated or in situations where a high dosage of the
drug product can be used. This category also provides a buffer zone that
prevents small uncontrolled technical factors from causing major discrepancies
in interpretation. A report of “Resistant” indicates that the antimicrobial is not
likely to inhibit growth of the pathogen if the antimicrobial compound reaches
the concentrations usually achievable at the infection site; other therapy
should be selected.
Quality Control
Standardized susceptibility test procedures require the
use of laboratory controls to monitor and ensure the accuracy and precision of
supplies and reagents used in the assay and the techniques of the individuals
performing the test.1,2,3,4,5 Standard moxifloxacin powder should provide the
following range of MIC values noted in Table 9. For the diffusion technique
using the 5 mcg moxifloxacin disk, the criteria in Table 9 should be achieved.
Table 9: Acceptable Quality Control Ranges for
Moxifloxacin
Strains |
MIC range (mcg/mL) |
Zone Diameter (mm) |
Enterococcus faecalis ATCC 29212 |
0.06-0.5 |
- |
Escherichia coli ATCC 25922 |
0.008-0.06 |
28-35 |
Haemophilus influenzae ATCC 49247 |
0.008-0.03 |
31-39 |
Staphylococcus aureus ATCC 29213 |
0.015-0.06 |
- |
Staphylococcus aureus ATCC 25923 |
- |
28-35 |
Streptococcus pneumoniae ATCC 49619 |
0.06-0.25 |
25-31 |
Bacteroides fragilis ATCC 25285 |
0.125-0.5 |
- |
Bacteroides thetaiotaomicron ATCC 29741 |
1-4 |
- |
Eubacterium lentum ATCC 43055 |
0.125-0.5 |
- |
Animal Toxicology And/Or Pharmacology
Fluoroquinolones have been shown to cause arthropathy in
immature animals. In studies in juvenile dogs oral doses of moxifloxacin 30
mg/kg/day or more (approximately 1.5 times the maximum recommended human dose
based upon systemic exposure) for 28 days resulted in arthropathy. There was no
evidence of arthropathy in mature monkeys and rats at oral doses up to 135 and
500 mg/kg/day, respectively.
Moxifloxacin at an oral dose of 300 mg/kg did not show an
increase in acute toxicity or potential for CNS toxicity (for example,
seizures) in mice when used in combination with NSAIDs such as diclofenac,
ibuprofen, or fenbufen. Some fluoroquinolones have been reported to have
proconvulsant activity that is exacerbated with concomitant use of NSAIDs.
A QT-prolonging effect of moxifloxacin was found in dog
studies, at plasma concentrations about five times the human therapeutic level.
The combined infusion of sotalol, a Class III antiarrhythmic agent, with moxifloxacin
induced a higher degree of QTc prolongation in dogs than that induced by the
same dose (30 mg/kg) of moxifloxacin alone. Electrophysiological in vitro studies
suggested an inhibition of the rapid activating component of the delayed
rectifier potassium current (I ) as an underlying mechanism.
No signs of local intolerability were observed in dogs
when moxifloxacin was administered intravenously. After intra-arterial
injection, inflammatory changes involving the peri-arterial soft tissue were
observed suggesting that intra-arterial administration of AVELOX should be
avoided.
Clinical Studies
Acute Bacterial Sinusitis
In a controlled double-blind study conducted in the US,
AVELOX Tablets (400 mg once daily for ten days) were compared with cefuroxime
axetil (250 mg twice daily for ten days) for the treatment of acute bacterial
sinusitis. The trial included 457 patients valid for the efficacy analysis.
Clinical success (cure plus improvement) at the 7 to 21 day post-therapy test
of cure visit was 90% for AVELOX and 89% for cefuroxime.
An additional non-comparative study was conducted to
gather bacteriological data and to evaluate microbiological eradication in
adult patients treated with AVELOX 400 mg once daily for seven days. All
patients (n = 336) underwent antral puncture in this study. Clinical success
rates and eradication/presumed eradication rates at the 21 to 37 day follow-up
visit were 97% (29 out of 30) for Streptococcus pneumoniae, 83% (15 out
of 18) for Moraxella catarrhalis, and 80% (24 out of 30) for Haemophilus
influenzae.
Acute Bacterial Exacerbation Of Chronic Bronchitis
AVELOX Tablets (400 mg once daily for five days) were
evaluated for the treatment of acute bacterial exacerbation of chronic
bronchitis in a randomized, double-blind, controlled clinical trial conducted
in the US. This study compared AVELOX with clarithromycin (500 mg twice daily
for 10 days) and enrolled 629 patients. Clinical success was assessed at 7-17
days post-therapy. The clinical success for AVELOX was 89% (222/250) compared
to 89% (224/251) for clarithromycin.
Table 10: Clinical Success Rates at Follow-Up Visit
for Clinically Evaluable Patients by Pathogen (Acute Bacterial Exacerbation of
Chronic Bronchitis)
PATHOGEN |
AVELOX |
Clarithromycin |
Streptococcus pneumoniae |
16/16 (100%) |
20/23 (87%) |
Haemophilus influenzae |
33/37 (89%) |
36/41 (88%) |
Haemophilus parainfluenzae |
16/16 (100%) |
14/14 (100%) |
Moraxella catarrhalis |
29/34 (85%) |
24/24 (100%) |
Staphylococcus aureus |
15/16 (94%) |
6/8 (75%) |
Klebsiella pneumoniae |
18/20 (90%) |
10/11 (91%) |
The microbiological eradication rates (eradication plus
presumed eradication) in AVELOX treated patients were Streptococcus
pneumoniae 100%, Haemophilus influenzae 89%, Haemophilus parainfluenzae
100%, Moraxella catarrhalis 85%, Staphylococcus aureus 94%, and Klebsiella
pneumonia 85%.
Community Acquired Pneumonia
A randomized, double-blind, controlled clinical trial was
conducted in the US to compare the efficacy of AVELOX Tablets (400 mg once
daily) to that of high-dose clarithromycin (500 mg twice daily) in the
treatment of patients with clinically and radiologically documented community
acquired pneumonia. This study enrolled 474 patients (382 of whom were valid
for the efficacy analysis conducted at the 14-35 day follow-up visit). Clinical
success for clinically evaluable patients was 95% (184/194) for AVELOX and 95%
(178/188) for high dose clarithromycin.
A randomized, double-blind, controlled trial was
conducted in the US and Canada to compare the efficacy of sequential
intravenous/oral AVELOX 400 mg once a day for 7-14 days to an intravenous/oral
fluoroquinolone control (trovafloxacin or levofloxacin) in the treatment of
patients with clinically and radiologically documented community acquired
pneumonia. This study enrolled 516 patients, 362 of whom were valid for the
efficacy analysis conducted at the 7-30 day post-therapy visit. The clinical
success rate was 86% (157/182) for AVELOX therapy and 89% (161/180) for the fluoroquinolone
comparators.
An open-label ex-US study that enrolled 628 patients
compared AVELOX to sequential intravenous/oral amoxicillin/clavulanate (1.2
gram intravenously every 8 hours/625 mg orally every 8 hours) with or without
high-dose intravenous/oral clarithromycin (500 mg twice a day). The intravenous
formulations of the comparators are not FDA approved. The clinical success rate
at Day 5-7 for AVELOX therapy was 93% (241/258) and demonstrated superiority to
amoxicillin/clavulanate ± clarithromycin (85%, 239/280) [95% C.I. of difference
in success rates between moxifloxacin and comparator (2.9%, 13.2%)]. The
clinical success rate at the 21-28 days post-therapy visit for AVELOX was 84% (216/258),
which also demonstrated superiority to the comparators (74%, 208/280) [95% C.I.
of difference in success rates between moxifloxacin and comparator (2.6%,
16.3%)].
The clinical success rates by pathogen across four CAP
studies are presented in Table 11.
Table 11: Clinical Success Rates By Pathogen (Pooled
CAP Studies)
PATHOGEN |
AVELOX |
Streptococcus pneumoniae |
80/85(94%) |
Staphylococcus aureus |
17/20(85%) |
Klebsiella pneumoniae |
11/12(92%) |
Haemophilus influenzae |
56/61(92%) |
Chlamydophila pneumoniae |
119/128(93%) |
Mycoplasma pneumoniae |
73/76(96%) |
Moraxella catarrhalis |
11/12(92%) |
Community Acquired Pneumonia Caused By Multi-Drug
Resistant Streptococcus pneumoniae (MDRSP)*
AVELOX was effective in the treatment of community
acquired pneumonia (CAP) caused by multi-drug resistant Streptococcus
pneumoniae MDRSP* isolates. Of 37 microbiologically evaluable patients with
MDRSP isolates, 35 patients (95%) achieved clinical and bacteriological success
post-therapy. The clinical and bacteriological success rates based on the
number of patients treated are shown in Table 12.
* MDRSP, Multi-drug resistant Streptococcus pneumoniae
includes isolates previously known as PRSP (Penicillin-resistant S.
pneumoniae), and are isolates resistant to two or more of the following antibiotics:
penicillin (MIC ≥ 2 mcg/mL), 2nd generation cephalosporins (for example,
cefuroxime), macrolides, tetracyclines, and trimethoprim/sulfamethoxazole.
Table 12: Clinical and Bacteriological Success Rates
for AVELOX-Treated MDRSP CAP Patients (Population: Valid for Efficacy)
Screening Susceptibility |
Clinical Success |
Bacteriological Success |
n/Na |
% |
n/Nb |
% |
Penicillin-resistant |
21/21 |
100%c |
21/21 |
100%c |
2nd generation cephalosporin-resistant |
25/26 |
96%c |
25/26 |
96%c |
Macrolide-resistantd |
22/23 |
96% |
22/23 |
96% |
Trimethoprim/sulfamethoxazole-resistant |
28/30 |
93% |
28/30 |
93% |
Tetracycline-resistant |
17/18 |
94% |
17/18 |
94% |
an = number of patients successfully treated;
N = number of patients with MDRSP (from a total of 37 patients)
bn = number of patients successfully treated (presumed eradication
or eradication); N = number of patients with MDRSP (from a total of 37
patients)
cOne patient had a respiratory isolate that was resistant to
penicillin and cefuroxime but a blood isolate that was intermediate to
penicillin and cefuroxime. The patient is included in the database based on the
respiratory isolate.
dAzithromycin, clarithromycin, and erythromycin were the macrolide
antimicrobials tested. |
Not all isolates were resistant to all antimicrobial
classes tested. Success and eradication rates are summarized in Table 13.
Table 13: Clinical Success Rates and Microbiological
Eradication Rates for Resistant Streptococcus pneumoniae (Community Acquired
Pneumonia)
S. pneumoniae with MDRSP |
Clinical Success |
Bacteriological Eradication Rate |
Resistant to 2 antimicrobials |
12/13 (92.3 %) |
12/13 (92.3 %) |
Resistant to 3 antimicrobials |
10/11 (90.9 %)a |
10/11 (90.9 %)a |
Resistant to 4 antimicrobials |
6/6 (100%) |
6/6 (100%) |
Resistant to 5 antimicrobials |
7/7 (100%)a |
7/7 (100%)a |
Bacteremia with MDRSP |
9/9 (100%) |
9/9 (100%) |
aOne patient had a respiratory isolate
resistant to 5 antimicrobials and a blood isolate resistant to 3 antimicrobials.
The patient was included in the category resistant to 5 antimicrobials. |
Uncomplicated Skin And Skin Structure Infections
A randomized, double-blind, controlled clinical trial
conducted in the US compared the efficacy of AVELOX 400 mg once daily for seven
days with cephalexin HCl 500 mg three times daily for seven days. The
percentage of patients treated for uncomplicated abscesses was 30%, furuncles
8%, cellulitis 16%, impetigo 20%, and other skin infections 26%. Adjunctive
procedures (incision and drainage or debridement) were performed on 17% of the
AVELOX treated patients and 14% of the comparator treated patients. Clinical
success rates in evaluable patients were 89% (108/122) for AVELOX and 91% (110/121)
for cephalexin HCl.
Complicated Skin And Skin Structure Infections
Two randomized, active controlled trials of cSSSI were
performed. A double-blind trial was conducted primarily in North America to
compare the efficacy of sequential intravenous/oral AVELOX 400 mg once a day
for 7-14 days to an intravenous/oral beta-lactam/beta-lactamase inhibitor
control in the treatment of patients with cSSSI. This study enrolled 617
patients, 335 of which were valid for the efficacy analysis. A second
open-label International study compared AVELOX 400 mg once a day for 7-21 days
to sequential intravenous/oral beta-lactam/beta-lactamase inhibitor control in
the treatment of patients with cSSSI. This study enrolled 804 patients, 632 of
which were valid for the efficacy analysis. Surgical incision and drainage or
debridement was performed on 55% of the AVELOX treated and 53% of the
comparator treated patients in these studies and formed an integral part of
therapy for this indication. Success rates varied with the type of diagnosis
ranging from 61% in patients with infected ulcers to 90% in patients with
complicated erysipelas. These rates were similar to those seen with comparator
drugs. The overall success rates in the evaluable patients and the clinical
success by pathogen are shown in Tables 14 and 15.
Table 14: Overall Clinical Success Rates in Patients
with Complicated Skin and Skin Structure Infections
Study |
AVELOX n/N (%) |
Comparator n/N (%) |
95% Confidence Interval a |
North America |
125/162 (77.2%) |
141/173 (81.5%) |
(-14.4%, 2%) |
International |
254/315 (80.6%) |
268/317 (84.5%) |
(-9.4%, 2.2%) |
aof difference in success rates between
Moxifloxacin and comparator (Moxifloxacin - comparator) |
Table 15: Clinical Success Rates by Pathogen in
Patients with Complicated Skin and Skin Structure Infections
Pathogen |
AVELOX n/ N (%) |
Comparator n/N (%) |
Staphylococcus aureus (methicillin-susceptible isolates)a |
106/129 (82.2%) |
120/137 (87.6%) |
Escherichia coli |
31/38 (81.6 %) |
28/33 (84.8 %) |
Klebsiella pneumoniae |
11/12 (91.7 % ) |
7/10 (70%) |
Enterobacter cloacae |
9/11 (81.8%) |
4/7 (57.1%) |
amethicillin susceptibility was only
determined in the North American Study |
Complicated Intra-Abdominal Infections
Two randomized, active controlled trials of cIAI were
performed. A double-blind trial was conducted primarily in North America to
compare the efficacy of sequential intravenous/oral AVELOX 400 mg once a day
for 5-14 days to intravenous/piperacillin/tazobactam followed by oral
amoxicillin/clavulanic acid in the treatment of patients with cIAI, including
peritonitis, abscesses, appendicitis with perforation, and bowel perforation.
This study enrolled 681 patients, 379 of which were considered clinically
evaluable. A second open-label international study compared AVELOX 400 mg once
a day for 5-14 days to intravenous ceftriaxone plus intravenous metronidazole
followed by oral amoxicillin/clavulanic acid in the treatment of patients with
cIAI. This study enrolled 595 patients, 511 of which were considered clinically
evaluable. The clinically evaluable population consisted of subjects with a
surgically confirmed complicated infection, at least 5 days of treatment and a
25-50 day follow-up assessment for patients at the Test of Cure visit. The
overall clinical success rates in the clinically evaluable patients are shown
in Table 16.
Table 16: Clinical Success Rates in Patients with
Complicated Intra-Abdominal Infections
Study |
AVELOX n/ N (%) |
Comparator n/N (%) |
95% Confidence Intervala |
North America (overall) |
146/183 (79.8%) |
153/196 (78.1%) |
(-7.4%, 9.3%) |
Abscess |
40/57 (70.2%) |
49/63 (77.8%)b |
NAc |
Non-abscess |
106/126 (84.1%) |
104/133 (78.2%) |
NA |
International (overall) |
199/246 (80.9%) |
218/265 (82.3%) |
(-8.9%, 4.2%) |
Abscess |
73/93 (78.5%) |
86/99 (86.9%) |
NA |
Non-abscess |
126/153 (82.4%) |
132/166 (79.5%) |
NA |
aof difference in success rates between AVELOX
and comparator (AVELOX - comparator)
bExcludes 2 patients who required additional surgery within the
first 48 hours.
cNA - not applicable |
Plague
Efficacy studies of AVELOX could not be conducted in
humans with pneumonic plague for ethical and feasibility reasons. Therefore,
approval of this indication was based on an efficacy study conducted in animals
and supportive pharmacokinetic data in adult humans and animals.
A randomized, blinded, placebo-controlled study was
conducted in an African Green Monkey (AGM) animal model of pneumonic plague.
Twenty AGM (10 males and 10 females) were exposed to an inhaled mean (± SD)
dose of 100 ± 50 LD50 (range 92 to 127 LD50) of Yersinia pestis (CO92
strain) aerosol. The minimal inhibitory concentration (MIC) of moxifloxacin for
the Y. pestis strain used in this study was 0.06 mcg/mL. Development of
sustained fever for at least 4 hours duration was used as the trigger for the
initiation of 10 days of treatment with either a humanized regimen of
moxifloxacin or placebo. All study animals were febrile and bacteremic with Y.
pestis prior to the initiation of study treatment. Ten of 10 (100%) of the
animals receiving the placebo succumbed to disease between 83 to 139 h (mean 115
± 19 hours) post treatment. Ten of 10 (100%) moxifloxacin-treated animals
survived for the 30-day period after completion of the study treatment.
Compared to the placebo group, mortality in the moxifloxacin group was
significantly lower (difference in survival: 100% with a two-sided 95% exact confidence
interval [66.3%, 100%], p-value < 0.0001).
The mean plasma concentrations of moxifloxacin associated
with a statistically significant improvement in survival over placebo in an AGM
model of pneumonic plague are reached or exceeded in human adults receiving the
recommended oral and intravenous dosage regimens. The mean (± SD) peak plasma concentration
(Cmax) and total plasma exposure defined as the area under the plasma
concentration-time curve (AUC) in human adults receiving 400 mg intravenously
were 3.9 ± 0.9 mcg/mL and 39.3 ± 8.6 mcg•h/mL, respectively [see CLINICAL
PHARMACOLOGY]. The mean (± SD) peak plasma concentration and AUC0-24 in AGM
following one- day administration of a humanized dosing regimen simulating the human
AUC0-24 at a 400 mg dose were 4.4 ± 1.5 mcg/mL and 22 ± 8.0 mcg·h/mL,
respectively.
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