CLINICAL PHARMACOLOGY
Mechanism Of Action
Azithromycin is a macrolide antibacterial drug. [See
Microbiology]
Pharmacodynamics
Cardiac Electrophysiology
QTc interval prolongation was studied in a randomized,
placebo-controlled parallel trial in 116 healthy subjects who received either
chloroquine (1000 mg) alone or in combination with azithromycin (500 mg, 1000
mg, and 1500 mg once daily). Co-administration of azithromycin increased the
QTc interval in a dose-and concentration-dependent manner. In comparison to
chloroquine alone, the maximum mean (95% upper confidence bound) increases in QTcF
were 5 (10) ms, 7 (12) ms and 9 (14) ms with the co-administration of 500 mg,
1000 mg and 1500 mg azithromycin, respectively.
Pharmacokinetics
Zmax is an extended-release microsphere formulation.
Based on data obtained from studies evaluating the pharmacokinetics of
azithromycin in healthy adult subjects a higher peak serum concentration (Cmax)
and greater systemic exposure (AUC 0-24) of azithromycin are achieved on the
day of dosing following a single 2 g dose of Zmax versus 1.5 g of azithromycin tablets
administered over 3 days (500 mg/day) or 5 days (500 mg on day 1, 250 mg/day on
days 2-5) [Table 2]. Consequently, due to these different pharmacokinetic
profiles, Zmax is not interchangeable with azithromycin tablet 3-day and 5-day
dosing regimens.
Table 2: Mean (SD) Pharmacokinetic Parameters for
Azithromycin on Day 1 Following the Administration of a Single Dose of 2 g Zmax
or 1.5 g of Azithromycin Tablets Given over 3 Days (500 mg/day) or 5 Days (500
mg on Day 1 and 250 mg on Days 2-5) to Healthy Adult Subjects
Pharmacokinetic Parameter |
Azithromycin Regimen |
Zmax
[N=4]† |
3-day ‡
[N=12] |
5-day‡
[N=12] |
Cmax (mcg/mL) |
0.821 (0.281) |
0.441 (0.223) |
0.434 (0.202) |
Tmax§ (hr) |
5.0 (2.0-8.0) |
2.5 (1.0-4.0) |
2.5 (1.0-6.0) |
AUC0-24 (mcg•hr/mL) |
8.62 (2.34) |
2.58 (0.84) |
2.60 (0.71) |
AUC0-∞ (mcg•hr/mL) |
20.0 (6.66) |
17.4 (6.2) |
14.9 (3.1) |
t½ (hr) |
58.8 (6.91) |
71.8 (14.7) |
68.9 (13.8) |
* Zmax, 3-day and 5-day regimen parameters obtained from
separate pharmacokinetic studies
† N = 21 for AUC0-∞ and t½
‡ Cmax, Tmax and AUC0-24 values for Day 1 only
§ Median (range)
¶Total AUC for the 1-day, 3-day and 5-day
regimens
SD = standard deviation
Cmax = maximum serum concentration
Tmax = time to Cmax
AUC = area under concentration vs. time curve
t½ = terminal serum half-life |
Absorption
The bioavailability of Zmax
relative to azithromycin immediate release (IR) (powder for oral suspension)
was 83%. On average, peak serum concentrations were achieved approximately 2.5
hr later following Zmax administration and were lower by 57%, compared to 2 g
azithromycin IR. Thus, single 2 g doses of Zmax and azithromycin IR are not
bioequivalent and are not interchangeable.
Effect of food on absorption: A
high-fat meal increased the rate and extent of absorption of a 2 g dose of Zmax
(115% increase in Cmax, and 23% increase in AUC0-72) compared to the fasted
state. A standard meal also increased the rate of absorption (119% increase in
Cmax) and with less effect on the extent of absorption (12% increase in AUC0-72)
compared to administration of a 2 g Zmax dose in the fasted state.
Effect of antacids: Following
the administration of Zmax with an aluminum and magnesium hydroxide antacid,
the rate and extent of azithromycin absorption were not altered.
Distribution
The serum protein binding of
azithromycin is concentration dependent, decreasing from 51% at 0.02 mcg/mL to
7% at 2 mcg/mL. Following oral administration, azithromycin is widely
distributed throughout the body with an apparent steady-state volume of
distribution of 31.1 L/kg.
Azithromycin concentrates in
fibroblasts, epithelial cells, macrophages, and circulating neutrophils and
monocytes. Higher azithromycin concentrations in tissues than in plasma or
serum have been observed. White blood cell and lung exposure data in humans
following a single 2 g dose of Zmax in adults are shown in Table 3. Following a
2 g single dose of Zmax, azithromycin achieved higher exposure (AUC0-120) in
mononuclear leukocytes (MNL) and polymorphonuclear leukocytes (PMNL) than in
serum. The azithromycin exposure (AUC0-72) in lung tissue and alveolar cells
(AC) was approximately 100 times that in serum; and the exposure in epithelial
lining fluid (ELF) was also higher (approximately 2-3 times) than in serum. The
clinical significance of this distribution data is unknown.
Table 3: Azithromycin Exposure Data in White Blood
Cells and Lung Following a 2 g SingleDose of Zmax in Adults
A single 2 g dose of Zmax |
WBC |
Cmax (mcg/mL) |
AUC0-24 (mcg•hr/mL) |
AU C0-120 (mcg• hr/mL) |
Ct=120† (mcg/mL) |
MNL‡ |
116 (40.2) |
1790 (540) |
4710 (1100) |
16.2 (5.51) |
PMNL‡ |
146 (66.0) |
2080 (650) |
10000 (2690) |
81.7 (23.3) |
LUNG |
Cmax (mcg/mL) |
AUC0-24 (mcg•hr/mL) |
AUC0-72 (mcg•hr/mL) |
|
ALVEOLAR CELL¶ |
669 |
7028 |
20403 |
- |
ELF¶ |
3.2 |
17.6 |
131 |
- |
|
Cmax (mcg/g) |
AUC0-24 (mcg•hr/g) |
AUC0-72 (mcg•hr/g) |
|
LUNG TISSUE¶ |
37.9 |
505 |
1693 |
- |
Abbreviation: WBC: white blood cells; MNL: mononuclear
leukocytes; PMNL: polymorphonuclear leukocytes; ELF: Epithelial lining fluid
† Azithromycin concentration at 120 hr after the
start of dosing
‡ Data are presented as mean (standard deviation)
¶Cmax and AUC were calculated based on composite profile (n = 4 subjects/time
point/formulation). |
Following a regimen of 500 mg of
azithromycin tablets on the first day and 250 mg daily for 4 days, only very
low concentrations were noted in cerebrospinal fluid (less than 0.01 mcg/mL) in
the presence of non-inflamed meninges.
Metabolism
In vitro and in vivo studies to assess the metabolism of
azithromycin have not been performed.
Excretion
Serum azithromycin
concentrations following a single 2 g dose of Zmax declined in a polyphasic
pattern with a terminal elimination half-life of 59 hr. The prolonged terminal
half-life is thought to be due to a large apparent volume of distribution.
Biliary excretion of
azithromycin, predominantly as unchanged drug, is a major route of elimination.
Over the course of a week, approximately 6% of the administered dose appears as
unchanged drug in urine.
Specific Populations
Renal Insufficiency
Azithromycin pharmacokinetics
were investigated in 42 adults (21 to 85 years of age) with varying degrees of
renal impairment. Following the oral administration of a single 1.0 g dose of
azithromycin (4 Ã 250 mg capsules), the mean Cmax and AUC0-120 were 5.1% and
4.2% higher, respectively in subjects with GFR 10 to 80 mL/min compared to
subjects with normal renal function (GFR > 80 mL/min). The mean Cmax and AUC0-120
were 61% and 35% higher, respectively in subjects with GFR < 10 mL/min
compared to subjects with normal renal function. [See Use in Specific
Populations, Renal Impairment]
Hepatic Insufficiency
The pharmacokinetics of azithromycin in subjects with
hepatic impairment has not been established.
Pediatric Patients
The pharmacokinetics of azithromycin were characterized
following a single 60 mg/kg dose of Zmax in pediatric patients aged 3 months to
16 years. Although there was high inter-patient variability in systemic
exposure (AUC and Cmax) across the age groups studied, individual azithromycin
AUC and Cmax values in pediatric patients were comparable to or higher than
those following administration of 2 g Zmax in adults (Table 4). [See Use in
Specific Populations]
Table 4: Mean (SD) Pharmacokinetic Parameters for
Azithromycin Following Administration of a Single Dose of Zmax (60 mg/kg,
maximum dose of 2 g) to Pediatric Subjects Aged 3 Months to 16 Years
Treatment Group |
Pharmacokinetic Parameters |
Cmax (mcg/mL) |
T* max (hr) |
AUC(0-24) (mcg•hr/mL ) |
AUC(0-∞) (mcg•hr/mL ) |
Group 1 (N = 6) [3 to 18 months] |
0.74 (0.20) |
3 (3-3) |
6.29 (1.17) |
14.1 (2.16) (n = 3) |
Group 2† (N = 6) [ > 18 to 36 months] |
1.88†(0.50) |
3 (3-3) |
19.7f (5.35) |
37.3 (12.9) (n = 5) |
Group 3 (N = 6) [ > 36 to 48 months] |
1.23 (0.42) |
3 (3-6) |
12.9 (3.79) |
22.4 (5.96) |
Group 4 (N = 6) [ > 48 months to 8 years] |
1.13 (0.34) |
3 (3-6) |
13.0 (4.21) |
22.2 (6.89) |
Group 5 (N = 6) [ > 8 to 12 years] |
1.65 (0.38) |
3 (3-6) |
16.0 (4.99) |
30.1 (10.7) |
Group 6 (N = 6) [ > 12 to 16 years] |
0.98 (0.35) |
3 (3-6) |
11.0 (4.78) |
21.3 (9.37) |
Pooled 1-6 (N = 36) [On an empty stomach] |
1.27 (0.53) |
3 (3-6) |
13.1 (5.78) |
25.2 (10.7) (n = 32) |
Group 7‡ (N = 7) [Fed; 18 months to 8 years] |
1.41 (0.62) |
3 (1.5-3.1) |
7.43 (3.00) |
18.9 (3.57) (n = 3) |
Empty stomach = dosed with Zmax
at least 1 hr before or 2 hr after a meal (Groups I-VI) Fed = dosed with Zmax
within 5 minutes of consuming an age-appropriate high-fat breakfast (Group VII)
* Median (range) presented only for Tmax
† High mean values were driven by 2 subjects with
high exposure
‡ One subject vomited immediately after dosing and discontinued from the study |
Gender
The impact of gender on the
pharmacokinetics of azithromycin has not been evaluated for Zmax. However,
previous studies have demonstrated no significant differences in the
disposition of azithromycin between male and female subjects.
Pharmacokinetic Interaction
Studies
A drug interaction study was
performed with Zmax and antacids. All other drug interaction studies were
performed with azithromycin immediate release (IR) formulations (capsules and
tablets, doses ranging from 500 to 1200 mg) and other drugs likely to be
co-administered. The effects of coadministration of azithromycin on the
pharmacokinetics of other drugs are shown in Table 5 and the effects of other
drugs on the pharmacokinetics of azithromycin are shown in Table 6.
When used at therapeutic doses, azithromycin IR had a
minimal effect on the pharmacokinetics of atorvastatin, carbamazepine,
cetirizine, didanosine, efavirenz, fluconazole, indinavir, midazolam,
nelfinavir, sildenafil, theophylline (intravenous and oral), triazolam,
trimethoprim/sulfamethoxazole or zidovudine (Table 5). Although the drug
interaction studies were not conducted with Zmax, similar modest effect as
observed with IR formulation are expected since the total exposure to
azithromycin is comparable for Zmax and other azithromycin IR regimens.
Therefore, no dosage adjustment of drugs listed in Table 5 is recommended when
co-administered with Zmax.
Nelfinavir significantly increased the Cmax and AUC of
azithromycin following co-administration with azithromycin IR 1200 mg (Table
6). However, no dose adjustment of azithromycin is recommended when Zmax is
co-administered with nelfinavir.
Pharmacokinetic and/or pharmacodynamic interactions with
the drugs listed below have not been reported in clinical trials with
azithromycin; however, no specific drug interaction studies have been performed
to evaluate potential drug-drug interaction. Nonetheless, pharmacokinetic
and/or pharmacodynamic interactions with these drugs have been observed with
other macrolide products. Until further data are developed, careful monitoring
of patients is advised when azithromycin and these drugs are used
concomitantly: digoxin, ergotamine or dihydroergotamine, cyclosporine,
hexobarbital and phenytoin.
Table 5: Drug Interactions: Pharmacokinetic Parameters
of Co-administered Drugs in the Presence of Azithromycin
Co-administered Drug |
Dose of Coadministered Drug |
Dose of Azithromycin* |
n |
Ratio (with/without Azithromycin) of Co-administered Drug Pharmacokinetic Parameters
(90% CI); No Effect = 1.00 |
Mean Cmax |
Mean AUC |
Atorvastatin |
10 mg/day for 8 days |
500 mg/day orally on days 6-8 |
12 |
0.83 (0.63 to 1.08) |
1.01 (0.81 to 1.25) |
Carbamazepine |
200 mg/day for 2 days, then 200 mg twice a day for 18 days |
500 mg/day orally for days 16-18 |
7 |
0.97 (0.88 to 1.06) |
0.96 (0.88 to 1.06) |
Cetirizine |
20 mg/day for 11 days |
500 mg orally on day 7, then 250 mg/day on days 8-11 |
14 |
1.03 (0.93 to 1.14) |
1.02 (0.92 to 1.13) |
Didanosine |
200 mg orally twice a day for 21 days |
1,200 mg/day orally on days 8-21 |
6 |
1.44 (0.85 to 2.43) |
1.14 (0.83 to 1.57) |
Efavirenz |
400 mg/day for 7 days |
600 mg orally on day 7 |
14 |
1.04† |
0.95† |
Fluconazole |
200 mg orally single dose |
1,200 mg orally single dose |
18 |
1.04 (0.98 to 1.11) |
1.01 (0.97 to 1.05) |
Indinavir |
800 mg three times a day for 5 days |
1,200 mg orally on day 5 |
18 |
0.96 (0.86 to 1.08) |
0.90 (0.81 to 1.00) |
Midazolam |
15 mg orally on day 3 |
500 mg/day orally for 3 days |
12 |
1.27 (0.89 to 1.81) |
1.26 (1.01 to 1.56) |
Nelfinavir |
750 mg three times a day for 11 days |
1,200 mg orally on day 9 |
14 |
0.90 (0.81 to 1.01) |
0.85 (0.78 to 0.93) |
Sildenafil |
100 mg on days 1 and 4 |
500 mg/day orally for 3 days |
12 |
1.16 (0.86 to 1.57) |
0.92 (0.75 to 1.12) |
Theophylline |
4 mg/kg IV on days 1, 11, 25 |
500 mg orally on day 7, then 250 mg/day on days 8-11 |
10 |
1.19 (1.02 to 1.40) |
1.02 (0.86 to 1.22) |
Theophylline |
300 mg orally twice a day for 15 days |
500 mg orally on day 6, then 250 mg/day on days 7-10 |
8 |
1.09 (0.92 to 1.29) |
1.08 (0.89 to 1.31) |
Triazolam |
0.125 mg on day 2 |
500 mg orally on day 1, then 250 mg/day on day 2 |
12 |
1.06† |
1.02† |
Trimethoprim/ Sulfamethoxazole |
160 mg/800 mg/d ay orally for 7 days |
1,200 mg orally on day 7 |
12 |
0.85 (0.75 to 0.97)/ 0.90 (0.78 to 1.03) |
0.87 (0.80 to 0.95)/ 0.96 (0.88 to 1.03) |
Zidovudine |
500 mg/day orally for 21 days |
600 mg/day oraly for 14 days |
5 |
1.12 (0.42 to 3.02) |
0.94 (0.52 to 1.70) |
Zidovudine |
500 mg/day orally for 21 days |
1,200 mg/day orally for 14 days |
4 |
1.31 (0.43 to 3.97) |
1.30 (0.69 to 2.43) |
* Refers to azithromycin capsules and tablets unless
specified
† 90% confidence interval not reported |
Table 6: Drug Interactions:
Pharmacokinetic Parameters of Azithromycin in the Presence of Coadministered
Drugs
Co-administered Drug |
Dose of Coadministered Drug |
Dose of Azithromycin* |
n |
Ratio (with/without co-administered drug) of Azithromycin Pharmacokinetic Parameters
(90% CI); No Effect = 1.00 |
Mean Cmax |
Mean AUC |
Efavirenz |
400 mg/day for 7 days |
600 mg orally on day 7 |
14 |
1.22 (1.04 to 1.42) |
0.92† |
Fluconazole |
200 mg orally single dose |
1,200 mg orally single dose |
18 |
0.82 (0.66 to 1.02) |
1.07 (0.94 to 1.22) |
Nelfinavir |
750 mg three times a day 11 days |
1,200 mg orally on day 9 |
14 |
2.36 (1.77 to 3.15) |
2.12 (1.80 to 2.50) |
Aluminum and Magnesium hydroxide |
20 mL regular strength, single dose |
2 g Zmax, single dose |
39 |
0.99 (0.93 to 1.06) |
0.99 (0.92 to 1.08) |
* Refers to azithromycin capsules and tablets unless
specified
† 90% confidence interval not reported |
Microbiology
Mechanism Of Action
Azithromycin binds to the 23S
rRNA of the 50S ribosomal subunit and interferes with bacterial protein
synthesis by impeding the assembly of the 50S ribosomal subunit.
Resistance
Azithromycin demonstrates cross
resistance with erythromycin. The most frequently encountered mechanism of
resistance to azithromycin is modification of the 23S rRNA target, most often
by methylation. Ribosomal modifications can determine cross resistance to other
macrolides, lincosamides and streptogramin B (MLSB phenotype).
Azithromycin has been shown to
be active against the following microorganisms, both in vitro and in clinical
infections. [See INDICATIONS AND USAGE].
Gram-Positive Bacteria
Streptococcus pneumoniae
Gram-Negative Bacteria
Haemophilus influenzae
Moraxella catarrhalis
“Other” Bacteria
Chlamydophila pneumoniae
Mycoplasma pneumoniae
Susceptibility Testing
Methods
When available, the clinical
microbiology laboratory should provide the results of in vitro susceptibility
test results for antimicrobial 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 minimal
inhibitory concentrations (MICs). These MICs provide estimates of the
susceptibility of bacteria to antimicrobial compounds. The MICs should be
determined using a standardized test method1,3,4 (broth or agar).
The MIC values should be interpreted according to criteria provided in Table 7.
Diffusion Techniques
Quantitative methods that require measurement of zone
diameters can 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 should be
determined using a standardized method2,3,4. This procedure uses
paper disk impregnated with 15 mcg azithromycin to test the susceptibility of
bacteria to azithromycin. The disk diffusion interpretive criteria are provided
in Table 7.
Table 7: Susceptibility Interpretive Criteria for
Azithromycin
Pathogen |
Minimum Inhibitory Concentrations (mcg/mL) |
Disk Diffusion (zone diameter in mm) |
S |
I |
R |
S |
I |
R |
Haemophilus influenzae* |
≤ 4 |
- |
- |
≥ 12 |
- |
- |
Moraxella catarrhalis* |
≤ 0.25 |
- |
- |
≥ 26 |
- |
- |
Streptococcus pneumoniae |
≤ 0.5 |
1 |
≥ 2 |
≥ 18 |
14-17 |
≤ 13 |
* Insufficient information is
available to determine Intermediate or Resistant interpretive criteria |
A report of “Susceptible” (S)
indicates that the antimicrobial drug is likely to inhibit growth of the
pathogen if the antimicrobial drug reaches the concentration at the site of infection.
A report of “Intermediate” (I) 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. This category also provides a buffer zone that prevents small
uncontrolled technical factors from causing major discrepancies in
interpretation. A report of “Resistant” (R) indicates that the antimicrobial
drug is not likely to inhibit growth of the pathogen if the antimicrobial drug
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. Standard azithromycin powder should provide
the following range of MIC values provided in Table 8. For the diffusion
technique using the 15-mcg azithromycin disk the criteria provided in Table 8
should be achieved.
Table 8: Acceptable Quality Control Ranges for Susceptibility
Testing
Quality Control Organism |
Minimum Inhibitory Concentrations (mcg/mL) |
Disk Diffusion (zone diameters in mm) |
Haemophilus Influenzae ATCC 49247 |
1-4 |
13-21 |
Staphylococcus aureus ATCC 25923 |
Not Applicable |
21-26 |
Staphylococcus aureus ATCC 29213 |
0.5-2 |
Not Applicable |
Streptococcus pneumoniae ATCC 49619 |
0.06-0.25 |
19-25 |
ATCC = American Type Culture
Collection |
Animal Toxicology And/Or Pharmacology
Phospholipidosis (intracellular
phospholipid accumulation) has been observed in some tissues of mice, rats, and
dogs given multiple doses of azithromycin. It has been demonstrated in numerous
organ systems (e.g., eye, dorsal root ganglia, liver, gallbladder, kidney,
spleen, and/or pancreas) in dogs treated with azithromycin at doses which,
expressed on the basis of mg/m² , are approximately one-sixth the
recommended adult dose, and in rats treated at doses approximately one-fourth
the recommended adult dose. This effect has been shown to be reversible after
cessation of azithromycin treatment. Based on the pharmacokinetic data,
phospholipidosis has been seen in the rat (50 mg/kg/day dose) at the observed
maximal plasma concentration of 1.3 mcg/mL (1.6 times the observed Cmax of 0.821
mcg/mL at the adult dose of 2 g.). Similarly, it has been shown in the dog (10
mg/kg/day dose) at the observed maximal serum concentration of 1 mcg/mL (1.2
times the observed Cmax of 0.821 mcg/mL at the adult dose of 2 g).
Phospholipidosis was also
observed in neonatal rats dosed for 18 days at 30 mg/kg/day, which is less than
the pediatric dose of 60 mg/kgbased on the surface area. It was not observed in
neonatal rats treated for 10 days at 40 mg/kg/day with mean maximal serum
concentrations of 1.86 mcg/mL, approximately 1.5 times the Cmax of 1.27 mcg/mL
at the pediatric dose. Phospholipidosis has been observed in neonatal dogs (10
mg/kg/day) at maximum mean whole blood concentrations of 3.54 mcg/mL,
approximately 3 times the pediatric dose Cmax.
The significance of the finding
for animals and for humans is unknown.
Clinical Studies
Acute Bacterial Maxillary Sinusitis
Adult subjects with a diagnosis of acute bacterial
maxillary sinusitis were evaluated in a randomized, double-blind, multicenter
study; a maxillary sinus tap was performed on all subjects at baseline.
Clinical evaluations were conducted for all subjects at the TOC visit, 7 to 14
days post-treatment. Two hundred seventy (270) subjects were treated with a
single 2 g oral dose of Zmax and 268 subjects were treated with levofloxacin,
500 mg orally once daily for 10 days. A subject was considered a cure if signs
and symptoms related to the acute infection had resolved, or if clinical
improvement was such that no additional antibiotics were deemed necessary. The
clinical response for the primary population, Clinical Per Protocol Subjects,
is presented below.
Table 9: Clinical Response in Patients with Acute
Bacterial Maxillary Sinusitis
RESPONSE AT TOC |
ZMAX
N = 255 |
LEVOFLOXACIN
N = 254 |
CURE |
241 (94.5%) |
236 (92.9%) |
FAILURE |
14 (5.5%) |
18 (7.1%) |
Clinical response by pathogen
in the Bacteriologic Per Protocol population is presented below.
Table 10: Clinical Response
by Pathogen in Patients with Acute Bacterial Maxillary Sinusitis
Pathogen |
Zmax |
Levofloxacin |
N |
Cure |
N |
Cure |
S. pneumoniae |
37 |
36 (97.3%) |
39 |
36 (92.3%) |
H. influenzae |
27 |
26 (96.3%) |
30 |
30 (100.0%) |
M. catarrhalis |
8 |
8 (100.0%) |
11 |
10 (90.9%) |
Community-Acquired Pneumonia
Adult subjects with a diagnosis
of mild-to-moderate community-acquired pneumonia were evaluated in two,
randomized, double-blind, multicenter studies. In both studies, clinical and
microbiologic evaluations were conducted for all subjects at the Test of Cure
(TOC) visit, 7 to 14 days posttreatment. In Trial 1, 247 subjects were treated
with a single 2 g oral dose of Zmax and 252 subjects were treated with
clarithromycin extended-release, 1 g orally once daily for 7 days. In Trial 2,
211 subjects were treated with a single 2.0 g oral dose of Zmax and 212
subjects were treated with levofloxacin, 500 mg orally once daily for 7 days. A
patient was considered a cure if signs and symptoms related to the acute
infection had resolved, or if clinical improvement was such that no additional
antibiotics were deemed necessary; in addition, the chest x-ray performed at
the TOC visit was to be either improved or stable. The clinical response at TOC
for the primary population, Clinical Per Protocol Subjects, is presented in the
table below.
Table 11: Clinical Response at Test of Cure (TOC) in
Patients with Community-Acquired Pneumonia
Zmax vs. Clarithromycin extended-release |
Zmax
N=202 |
Comparator
N=209 |
Cure |
187 (92.6%) |
198 (94.7%) |
Failure |
15 (7.4%) |
11 (5.3%) |
Zmax vs. Levofloxacin |
N=174 |
N=189 |
Cure |
156 (89.7%) |
177 (93.7%) |
Failure |
18 (10.3%) |
12 (6.3%) |
Clinical response by pathogen
in the Bacteriologic Per Protocol population, across both studies, is presented
below:
Table 12: Clinical Response
by Pathogen in Patients with Community-Acquired Pneumonia
Pathogen |
Zmax |
Comparators |
N |
Cure |
N |
Cure |
S. pneumoniae |
33 |
28 (84.8%) |
39 |
35 (89.7%) |
H. influenzae |
30 |
28 (93.3%) |
34 |
31 (91.2%) |
C. pneumoniae |
40 |
37 (92.5%) |
53 |
50 (94.3%) |
M. pneumoniae |
33 |
30 (90.9%) |
39 |
38 (97.4%) |
REFERENCES
1. Clinical and Laboratory Standards Institute (CLSI).
Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow
Aerobically; Approved Standard -Tenth Edition. CLSI document M07-A10, Clinical
and Laboratory Standards Institute, 950 West Valley Road, Suite 2500, Wayne,
Pennsylvania 19087, USA, 2015.
2. Clinical and Laboratory Standards Institute (CLSI).
Performance Standards for Antimicrobial Susceptibility Testing; Twenty-Fifth
Informational Supplement. CLSI document M100-S25, Clinical and Laboratory
Standards Institute, 950 West Valley Road, Suite 2500, Wayne, Pennsylvania
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