CLINICAL PHARMACOLOGY
Mechanism Of Action
Clarithromycin is a macrolide antimicrobial drug [see Microbiology].
Pharmacokinetics
Absorption
BIAXIN Filmtab Immediate-Release Tablets
The absolute bioavailability of 250 mg clarithromycin
tablets was approximately 50%. For a single 500 mg dose of clarithromycin, food
slightly delays the onset of clarithromycin absorption, increasing the peak
time from approximately 2 to 2.5 hours. Food also increases the clarithromycin
peak plasma concentration by about 24%, but does not affect the extent of
clarithromycin bioavailability. Food does not affect the onset of formation of
the active metabolite, 14-OH clarithromycin or its peak plasma concentration
but does slightly decrease the extent of metabolite formation, indicated by an
11% decrease in area under the plasma concentration-time curve (AUC).
Therefore, BIAXIN Filmtab may be given without regard to food. In non-fasting
healthy human subjects (males and females), peak plasma concentrations were
attained within 2 to 3 hours after oral dosing.
BIAXIN XL Filmtab Extended-Release Tablets
Clarithromycin extended-release tablets provide extended
absorption of clarithromycin from the gastrointestinal tract after oral
administration. Relative to an equal total daily dose of immediate-release
clarithromycin tablets, clarithromycin extended-release tablets provide lower
and later steady-state peak plasma concentrations but equivalent 24-hour AUCs
for both clarithromycin and its microbiologically-active metabolite, 14-OH
clarithromycin. While the extent of formation of 14-OH clarithromycin following
administration of BIAXIN XL Filmtab (2 x 500 mg tablets once daily) is not
affected by food, administration under fasting conditions is associated with
approximately 30% lower clarithromycin AUC relative to administration with
food. Therefore, BIAXIN XL Filmtab should be taken with food.
Figure 2: Steady-State Clarithromycin Plasma
Concentration-Time Profiles
BIAXIN Granules For Oral Suspension
When 250 mg doses of clarithromycin as BIAXIN as an oral
suspension were administered to fasting healthy adult subjects, peak plasma
concentrations were attained around 3 hours after dosing.
For adult patients, the bioavailability of 10 mL of the
125 mg/5 mL suspension or 10 mL of the 250 mg/5 mL suspension is similar to a
250 mg or 500 mg tablet, respectively.
In adults given 250 mg clarithromycin as suspension (n =
22), food appeared to decrease mean peak plasma clarithromycin concentrations
from 1.2 (± 0.4) mcg/mL to 1.0 (± 0.4) mcg/mL and the extent of absorption from
7.2 (± 2.5) hr•mcg/mL to 6.5 (± 3.7) hr•mcg/mL.
Distribution
Clarithromycin and the 14-OH clarithromycin metabolite
distribute readily into body tissues and fluids. There are no data available on
cerebrospinal fluid penetration. Because of high intracellular concentrations,
tissue concentrations are higher than serum concentrations. Examples of tissue
and serum concentrations are presented below.
Table 9: Tissue and Serum Concentrations of
Clarithromycin
CONCENTRATION (after 250 mg every 12 hours) |
Tissue Type |
Tissue (mcg/g) |
Serum (mcg/mL) |
Tonsil |
1.6 |
0.8 |
Lung |
8.8 |
1.7 |
Metabolism And Elimination
BIAXIN Filmtab Immediate-Release Tablets
Steady-state peak plasma clarithromycin concentrations
were attained within 3 days and were approximately 1 mcg/mL to 2 mcg/mL with a
250 mg dose administered every 12 hours and 3 mcg/mL to 4 mcg/mL with a 500 mg
dose administered every 8 hours to 12 hours. The elimination half-life of
clarithromycin was about 3 hours to 4 hours with 250 mg administered every 12
hours but increased to 5 hours to 7 hours with 500 mg administered every 8
hours to 12 hours. The nonlinearity of clarithromycin pharmacokinetics is
slight at the recommended doses of 250 mg and 500 mg administered every 8 hours
to 12 hours. With a 250 mg every 12 hours dosing, the principal metabolite,
14-OH clarithromycin, attains a peak steady-state concentration of about 0.6
mcg/mL and has an elimination half-life of 5 hours to 6 hours. With a 500 mg
every 8 hours to 12 hours dosing, the peak steady-state concentration of 14-OH
clarithromycin is slightly higher (up to 1 mcg/mL), and its elimination
half-life is about 7 hours to 9 hours. With any of these dosing regimens, the
steady-state concentration of this metabolite is generally attained within 3
days to 4 days.
After a 250 mg tablet every 12 hours, approximately 20%
of the dose is excreted in the urine as clarithromycin, while after a 500 mg
tablet every 12 hours, the urinary excretion of clarithromycin is somewhat
greater, approximately 30%. In comparison, after an oral dose of 250 mg (125
mg/5 mL) suspension every 12 hours, approximately 40% is excreted in urine as
clarithromycin. The renal clearance of clarithromycin is, however, relatively
independent of the dose size and approximates the normal glomerular filtration
rate. The major metabolite found in urine is 14-OH clarithromycin, which
accounts for an additional 10% to 15% of the dose with either a 250 mg or a 500
mg tablet administered every 12 hours.
BIAXIN XL Filmtab Extended-Release Tablets
In healthy human subjects, steady-state peak plasma
clarithromycin concentrations of approximately 2 mcg/mL to 3 mcg/mL were
achieved about 5 hours to 8 hours after oral administration of 1000 mg BIAXIN
XL Filmtab once daily; for 14-OH clarithromycin, steady-state peak plasma
concentrations of approximately 0.8 mcg/mL were attained about 6 hours to 9
hours after dosing. Steady-state peak plasma clarithromycin concentrations of
approximately 1 mcg/mL to 2 mcg/mL were achieved about 5 hours to 6 hours after
oral administration of a single 500 mg BIAXIN XL Filmtab once daily; for 14-OH
clarithromycin, steady-state peak plasma concentrations of approximately 0.6
mcg/mL were attained about 6 hours after dosing.
Steady-state peak plasma concentrations were attained in
2 days to 3 days and were approximately 2 mcg/mL for clarithromycin and 0.7
mcg/mL for 14-OH clarithromycin when 250-mg doses of the clarithromycin
suspension were administered every 12 hours. Elimination half-life of
clarithromycin (3 hours to 4 hours) and that of 14-OH clarithromycin (5 hours
to 7 hours) were similar to those observed at steady state following
administration of equivalent doses of BIAXIN Filmtab.
Specific Populations For BIAXIN Filmtab, BIAXIN XL
Filmtab, And BIAXIN Granules Formulations
BIAXIN Granules For Oral Suspension In Pediatric
Patients
Clarithromycin penetrates into the middle ear fluid of
pediatric patients with secretory otitis media.
Table 10: Middle Ear Fluid and Serum Concentrations of
Clarithromycin and 14-OH-Clarithromycin in Pediatric Patients
CONCENTRATION (after 7.5 mg/kg every 12 hours for 5 doses) |
Analyte |
Middle Ear Fluid (mcg/mL) |
Serum (mcg/mL) |
Clarithromycin |
2.5 |
1.7 |
14-OH Clarithromycin |
1.3 |
0.8 |
When pediatric patients (n = 10) were administered a
single oral dose of 7.5 mg/kg BIAXIN as an oral suspension, food increased mean
peak plasma clarithromycin concentrations from 3.6 (± 1.5) mcg/mL to 4.6 (±
2.8) mcg/mL and the extent of absorption from 10.0 (± 5.5) hr•mcg/mL to 14.2 (±
9.4) hr•mcg/mL.
In pediatric patients requiring antibacterial therapy,
administration of 7.5 mg/kg every 12 hours of BIAXIN as an oral suspension
generally resulted in steady-state peak plasma concentrations of 3 mcg/mL to 7
mcg/mL for clarithromycin and 1 mcg/mL to 2 mcg/mL for 14-OH clarithromycin.
In HIV-infected pediatric patients taking 15 mg/kg of
BIAXIN as an oral suspension every 12 hours, steady-state clarithromycin peak
concentrations generally ranged from 6 mcg/mL to 15 mcg/mL.
HIV Infection
Steady-state concentrations of clarithromycin and 14-OH
clarithromycin observed following administration of 500 mg doses of clarithromycin
every 12 hours to adult patients with HIV infection were similar to those
observed in healthy volunteers. In adult HIV-infected patients taking 500-mg or
1000-mg doses of clarithromycin every 12 hours, steady-state clarithromycin Cmax
values ranged from 2 mcg/mL to 4 mcg/mL and 5 mcg/mL to 10 mcg/mL,
respectively.
Hepatic Impairment
The steady-state concentrations of clarithromycin in
subjects with impaired hepatic function did not differ from those in normal
subjects; however, the 14-OH clarithromycin concentrations were lower in the
hepatically impaired subjects. The decreased formation of 14-OH clarithromycin
was at least partially offset by an increase in renal clearance of
clarithromycin in the subjects with impaired hepatic function when compared to
healthy subjects.
Renal Impairment
The pharmacokinetics of clarithromycin was also altered
in subjects with impaired renal function [see Use In Specific Populations
and DOSAGE AND ADMINISTRATION].
Drug Interactions
Fluconazole
Following administration of fluconazole 200 mg daily and
clarithromycin 500 mg twice daily to 21 healthy volunteers, the steady-state
clarithromycin Cmin and AUC increased 33% and 18%, respectively. Clarithromycin
exposures were increased and steady-state concentrations of 14-OH
clarithromycin were not significantly affected by concomitant administration of
fluconazole.
Colchicine
When a single dose of colchicine 0.6 mg was administered
with clarithromycin 250 mg BID for 7 days, the colchicine Cmax increased 197%
and the AUC0-∞ increased 239% compared to administration of colchicine
alone.
Atazanavir
Following administration of clarithromycin (500 mg twice
daily) with atazanavir (400 mg once daily), the clarithromycin AUC increased
94%, the 14-OH clarithromycin AUC decreased 70% and the atazanavir AUC
increased 28%.
Ritonavir
Concomitant administration of clarithromycin and
ritonavir (n = 22) resulted in a 77% increase in clarithromycin AUC and a 100%
decrease in the AUC of 14-OH clarithromycin.
Saquinavir
Following administration of clarithromycin (500 mg bid)
and saquinavir (soft gelatin capsules, 1200 mg tid) to 12 healthy volunteers,
the steady-state saquinavir AUC and Cmax increased 177% and 187% respectively
compared to administration of saquinavir alone. Clarithromycin AUC and Cmax increased
45% and 39% respectively, whereas the 14–OH clarithromycin AUC and Cmax decreased
24% and 34% respectively, compared to administration with clarithromycin alone.
Didanosine
Simultaneous administration of clarithromycin tablets and
didanosine to 12 HIV-infected adult patients resulted in no statistically
significant change in didanosine pharmacokinetics.
Zidovudine
Following administration of clarithromycin 500 mg tablets
twice daily with zidovudine 100 mg every 4 hours, the steady-state zidovudine
AUC decreased 12% compared to administration of zidovudine alone (n=4).
Individual values ranged from a decrease of 34% to an increase of 14%. When
clarithromycin tablets were administered two to four hours prior to zidovudine,
the steady-state zidovudine Cmax increased 100% whereas the AUC was unaffected
(n=24).
Omeprazole
Clarithromycin 500 mg every 8 hours was given in
combination with omeprazole 40 mg daily to healthy adult subjects. The
steady-state plasma concentrations of omeprazole were increased (Cmax, AUC0-24,
and t½ increases of 30%, 89%, and 34%, respectively), by the concomitant
administration of clarithromycin.
The plasma levels of clarithromycin and 14–OH
clarithromycin were increased by the concomitant administration of omeprazole.
For clarithromycin, the mean Cmax was 10% greater, the mean Cmin was 27%
greater, and the mean AUC0-8 was 15% greater when clarithromycin was
administered with omeprazole than when clarithromycin was administered alone.
Similar results were seen for 14–OH clarithromycin, the mean Cmax was 45%
greater, the mean Cmin was 57% greater, and the mean AUC0-8 was 45% greater.
Clarithromycin concentrations in the gastric tissue and mucus were also
increased by concomitant administration of omeprazole.
Clarithromycin Tissue Concentrations 2 hours after
Dose (mcg/mL)/(mcg/g)
Treatment |
N |
antrum |
fundus |
N |
Mucus |
Clarithromycin |
5 |
10.48 ± 2.01 |
20.81 ± 7.64 |
4 |
4.15 ± 7.74 |
Clarithromycin + Omeprazole |
5 |
19.96 ± 4.71 |
24.25 ± 6.37 |
4 |
39.29 ± 32.79 |
Theophylline
In two studies in which theophylline was administered
with clarithromycin (a theophylline sustained-release formulation was dosed at
either 6.5 mg/kg or 12 mg/kg together with 250 or 500 mg q12h clarithromycin),
the steady-state levels of Cmax, Cmin, and the area under the serum
concentration time curve (AUC) of theophylline increased about 20%.
Midazolam
When a single dose of midazolam was co-administered with
clarithromycin tablets (500 mg twice daily for 7 days), midazolam AUC increased
174% after intravenous administration of midazolam and 600% after oral
administration.
For information about other drugs indicated in
combination with BIAXIN, refer to their full prescribing information, CLINICAL
PHARMACOLOGY section.
Microbiology
Mechanism Of Action
Clarithromycin exerts its antibacterial action by binding
to the 50S ribosomal subunit of susceptible bacteria resulting in inhibition of
protein synthesis.
Resistance
The major routes of resistance are modification of the
23S rRNA in the 50S ribosomal subunit to insensitivity or drug efflux pumps.
Beta-lactamase production should have no effect on clarithromycin activity.
Most isolates of methicillin-resistant and
oxacillin-resistant staphylococci are resistant to clarithromycin.
If H. pylori is not eradicated after treatment
with clarithromycin-containing combination regimens, patients may develop
clarithromycin resistance in H. pylori isolates. Therefore, for patients
who fail therapy, clarithromycin susceptibility testing should be done, if
possible. Patients with clarithromycin-resistant H. pylori should not be
treated with any of the following: omeprazole/clarithromycin dual therapy;
omeprazole/clarithromycin/amoxicillin triple therapy; lansoprazole/clarithromycin/amoxicillin
triple therapy; or other regimens which include clarithromycin as the sole
antibacterial agent.
Antimicrobial Activity
Clarithromycin has been shown to be active against most
of the isolates of the following microorganisms both in vitro and in clinical
infections [see INDICATIONS AND USAGE].
Gram-Positive Bacteria
- Staphylococcus aureus
- Streptococcus pneumoniae
- Streptococcus pyogenes
Gram-Negative Bacteria
- Haemophilus influenzae
- Haemophilus parainfluenzae
- Moraxella catarrhalis
Other Microorganisms
- Chlamydophila pneumoniae
- Helicobacter pylori
- Mycobacterium avium complex (MAC) consisting of M.
avium and M. intracellulare
- Mycoplasma pneumoniae
At least 90 percent of the microorganisms listed below
exhibit in vitro minimum inhibitory concentrations (MICs) less than or equal to
the clarithromycin susceptible MIC breakpoint for organisms of similar type to
those shown in Table 11. However, the efficacy of clarithromycin in treating
clinical infections due to these microorganisms has not been established in
adequate and well-controlled clinical trials.
Gram-Positive Bacteria
- Streptococcus agalactiae
- Streptococci (Groups C, F, G)
- Viridans group streptococci
Gram-Negative Bacteria
- Legionella pneumophila
- Pasteurella multocida
Anaerobic Bacteria
- Clostridium perfringens
- Peptococcus niger
- Prevotella melaninogenica
- Propionibacterium acnes
Susceptibility Testing
For specific information regarding susceptibility test
interpretive criteria, and associated test methods and quality control
standards recognized by FDA for this drug, please see: http://www.fda.gov/STIC.
Animal Toxicology And/Or Pharmacology
Corneal opacity occurred in dogs at doses 12 times and in
monkeys at doses 8 times greater than the maximum human daily dose (on a body
surface area basis). Lymphoid depletion occurred in dogs at doses 3 times
greater than and in monkeys at doses 2 times greater than the maximum human
daily dose (on a body surface area basis).
Clinical Studies
Mycobacterial Infections
Prophylaxis Of Mycobacterial Infections
A randomized, double-blind clinical trial (trial 3)
compared clarithromycin 500 mg twice a day to placebo in patients with
CDC-defined AIDS and CD4 counts less than 100 cells/μL. This trial accrued
682 patients from November 1992 to January 1994, with a median CD4 cell count
at entry of 30 cells/mcL. Median duration of BIAXIN was 10.6 months vs. 8.2
months for placebo. More patients in the placebo arm than the BIAXIN arm
discontinued prematurely from the trial (75.6% and 67.4%, respectively).
However, if premature discontinuations due to Mycobacterium avium complex (MAC)
or death are excluded, approximately equal percentages of patients on each arm
(54.8%) on BIAXIN and 52.5% on placebo) discontinued study drug early for other
reasons. The trial was designed to evaluate the following endpoints:
MAC bacteremia, defined as at least one positive culture
for Mycobacterium avium complex bacteria from blood or another normally sterile
site
Survival
Clinically significant disseminated MAC disease, defined
as MAC bacteremia accompanied by signs or symptoms of serious MAC infection,
including fever, night sweats, weight loss, anemia, or elevations in liver
function tests
MAC Bacteremia
In patients randomized to BIAXIN, the risk of MAC
bacteremia was reduced by 69% compared to placebo. The difference between
groups was statistically significant (p < 0.001). On an intent-to-treat
basis, the one-year cumulative incidence of MAC bacteremia was 5.0% for
patients randomized to BIAXIN and 19.4% for patients randomized to placebo.
While only 19 of the 341 patients randomized to BIAXIN developed MAC, 11 of
these cases were resistant to BIAXIN. The patients with resistant MAC
bacteremia had a median baseline CD4 count of 10 cells/mm³ (range 2 cells/mm³ to
25 cells/mm³). Information regarding the clinical course and response to
treatment of the patients with resistant MAC bacteremia is limited. The 8
patients who received BIAXIN and developed susceptible MAC bacteremia had a
median baseline CD4 count of 25 cells/mm³ (range 10 cells/mm³ to 80 cells/mm³).
Comparatively, 53 of the 341 placebo patients developed MAC; none of these
isolates were resistant to BIAXIN. The median baseline CD4 count was 15
cells/mm³ (range 2 cells/mm³ to 130 cells/mm³) for placebo patients that
developed MAC.
Survival
A statistically significant survival benefit of BIAXIN
compared to placebo was observed (see Figure 3 and Table 13). Since the
analysis at 18 months includes patients no longer receiving prophylaxis the
survival benefit of BIAXIN may be underestimated.
Figure 3: Survival of All Randomized AIDS Patients
Over Time in Trial 3
Table 13: Mortality Rates at 18 months in Trial 3
|
Mortality Rates |
Reduction in Mortality Rates on BIAXIN |
Placebo |
BIAXIN |
6 month |
9.4% |
6.5% |
31% |
12 month |
29.7% |
20.5% |
31% |
18 month |
46.4% |
37.5% |
20% |
Clinically Significant Disseminated MAC Disease
In association with the decreased incidence of MAC
bacteremia, patients in the group randomized to BIAXIN showed reductions in the
signs and symptoms of disseminated MAC disease, including fever, night sweats,
weight loss, and anemia.
Treatment of Mycobacterial Infections
Dose-Ranging Monotherapy Trials In Adult AIDS Patients With
MAC
Two randomized clinical trials (Trials 1 and 2) compared
different dosages of BIAXIN in patients with CDC-defined AIDS and CD4 counts
less than100 cells/mcL. These trials accrued patients from May 1991 to March
1992. Trial 500 was a randomized, double-blind trial; trial 577 was an
open-label compassionate use trial. Both trials used 500 mg and 1000 mg twice
daily dosing of BIAXIN; trial 1 also had a 2000 mg twice daily BIAXIN group.
Trial 1 enrolled 154 adult patients and trial 2 enrolled 469 adult patients.
The majority of patients had CD4 cell counts less than 50 cells/mcL at study
entry. The trials were designed to evaluate the following end points:
Change in MAC bacteremia or blood cultures negative for M.
avium.
Change in clinical signs and symptoms of MAC infection
including one or more of the following: fever, night sweats, weight loss,
diarrhea, splenomegaly, and hepatomegaly.
The results for trial 1 are described below. The trial 2
results were similar to the results of trial 1.
MAC Bacteremia
Decreases in MAC bacteremia or negative blood cultures
were seen in the majority of patients in all BIAXIN dosage groups. The mean
reductions in MAC colony forming units (CFU) from baseline after 4 weeks of
therapy in the 1000 mg (n=32) twice daily and 2000 mg (n=26) twice daily
regimen was 2.3 Log CFU compared to 1.5 Log CFU in the BIAXIN 500 mg twice
daily (n=35) regimen. A separate trial with a four-drug regimen2 (ciprofloxacin,
ethambutol, rifampicin, and clofazimine) had a mean reduction of 1.4 Log CFU.
Clinical outcomes evaluated with the different dosing
regimens of clarithromycin monotherapy are shown in Table 14. The 1000 mg and
2000 mg twice daily doses showed significantly better control of bacteremia
during the first four weeks of therapy. No significant differences were seen
beyond that point. All of the isolates had MIC less than 8 mcg/mL at
pre-treatment. Relapse was almost always accompanied by an increase in MIC.
Table 14: Outcome with the Different Dosing Regimens
of BIAXIN
Outcome |
BIAXIN 500 mg twice daily |
BIAXIN 1000 mg twice daily |
BIAXIN 2000 mg twice daily |
One or more negative blood cultures at any time during acute therapy |
61% (30/49) |
59% (29/49) |
52% (25/48) |
Two or more negative blood cultures during acute therapy sustained through study day 84 |
25% (12/49) |
25% (12/49) |
8% (4/48) |
Death or discontinuation by day 84 |
23% (11/49) |
37% (18/49) |
56% (27/48) |
Relapse by day 84 |
14% (7/49) |
12% (6/49) |
13% (6/48) |
Median time to first negative culture (in days) |
54 |
41 |
29 |
Median time to first decrease of at least 1 log CFU (in days) |
29 |
16 |
15 |
Median time to first positive culture or study discontinuation following the first negative culture (in days) |
43 |
59 |
43 |
Clinically Significant Disseminated MAC Disease
Among patients experiencing night sweats prior to therapy,
84% showed resolution or improvement at some point during the 12 weeks of
BIAXIN at 500 mg to 2000 mg twice daily doses. Similarly, 77% of patients
reported resolution or improvement in fevers at some point. Response rates for
clinical signs of MAC are given in Table 15 below.
The median duration of response, defined as improvement
or resolution of clinical signs and symptoms, was 2 weeks to 6 weeks.
Since the trial was not designed to determine the benefit
of monotherapy beyond 12 weeks, the duration of response may be underestimated
for the 25% to 33% of patients who continued to show clinical response after 12
weeks.
Table 15: Response Rates for Clinical Signs of MAC
During 6 Weeks to 12 Weeks of Treatment
Resolution of Fever |
Resolution of Night Sweats |
BIAXIN twice daily dose (mg) |
% ever afebrile |
% afebrile 6 weeks or more |
BIAXIN twice daily dose (mg) |
% ever resolving |
% resolving 6 weeks or more |
500 |
67% |
23% |
500 |
85% |
42% |
1000 |
67% |
12% |
1000 |
70% |
33% |
2000 |
62% |
22% |
2000 |
72% |
36% |
Weight |
Gain Greater Than 3% |
Hemoglobin Increase Greater Than 1 gm |
BIAXIN twice daily dose (mg) |
% ever gaining |
% gaining 6 weeks or more |
BIAXIN twice daily dose (mg) |
% ever increasing |
% increasing 6 weeks or more |
500 |
33% |
14% |
500 |
58% |
26% |
1000 |
26% |
17% |
1000 |
37% |
6% |
2000 |
26% |
12% |
2000 |
62% |
18% |
Survival
Median survival time from trial entry (trial 1) was 249
days at the 500 mg twice daily dose compared to 215 days with the 1000 mg twice
daily dose. However, during the first 12 weeks of therapy, there were 2 deaths
in 53 patients in the 500 mg twice daily group versus 13 deaths in 51 patients
in the 1000 mg twice daily group. The reason for this apparent mortality
difference is not known. Survival in the two groups was similar beyond 12
weeks. The median survival times for these dosages were similar to recent
historical controls with MAC when treated with combination therapies.2
Median survival time from entry in trial 2 was 199 days
for the 500 mg twice a day dose and 179 days for the 1000 mg twice a day dose.
During the first four weeks of therapy, while patients were maintained on their
originally assigned dose, there were 11 deaths in 255 patients taking 500 mg
twice daily and 18 deaths in 214 patients taking 1000 mg twice daily.
Dosage-Ranging Monotherapy Trials In Pediatric AIDS
Patients With MAC
Trial 4 was a pediatric trial of 3.75 mg/kg, 7.5 mg/kg,
and 15 mg/kg of BIAXIN twice daily in patients with CDC-defined AIDS and CD4 counts
less than 100 cells/mcL. The trial enrolled 25 patients between the ages of 1
to 20. The trial evaluated the same endpoints as in the adult trials 1 and 2.
Results with the 7.5 mg/kg twice daily dose in the pediatric trial were
comparable to those for the 500 mg twice daily regimen in the adult trials.
Combination Therapy In AIDS Patients With Disseminated
MAC
Trial 5 compared the safety and efficacy of BIAXIN in
combination with ethambutol versus BIAXIN in combination with ethambutol and
clofazimine for the treatment of disseminated MAC (dMAC) infection. This
24-week trial enrolled 106 patients with AIDS and dMAC, with 55 patients
randomized to receive BIAXIN and ethambutol, and 51 patients randomized to
receive clarithromycin, ethambutol, and clofazime. Baseline characteristics
between treatment arms were similar with the exception of median CFU counts
being at least 1 log higher in the BIAXIN, ethambutol, and clofazime arm.
Compared to prior experience with clarithromycin
monotherapy, the two-drug regimen of clarithromycin and ethambutol extended the
time to microbiologic relapse, largely through suppressing the emergence of
clarithromycin resistant strains. However, the addition of clofazimine to the
regimen added no additional microbiologic or clinical benefit. Tolerability of
both multidrug regimens was comparable with the most common adverse events
being gastrointestinal in nature. Patients receiving the clofazimine-containing
regimen had reduced survival rates; however, their baseline mycobacterial
colony counts were higher. The results of this trial support the addition of
ethambutol to clarithromycin for the treatment of initial dMAC infections but
do not support adding clofazimine as a third agent.
Otitis Media
Otitis Media Trial Of BIAXIN vs. Oral Cephalosporin
In a controlled clinical trial of pediatric patients with
acute otitis media performed in the United States, where significant rates of
beta-lactamase producing organisms were found, BIAXIN was compared to an oral
cephalosporin. In this trial, strict evaluability criteria were used to
determine clinical response. For the 223 patients who were evaluated for
clinical efficacy, the clinical success rate (i.e., cure plus improvement) at
the post-therapy visit was 88% for BIAXIN and 91% for the cephalosporin.
In a smaller number of patients, microbiologic
determinations were made at the pre-treatment visit. The presumptive bacterial
eradication/clinical cure outcomes (i.e., clinical success) are shown in Table
16.
Table 16: Clinical Success Rates of Otitis Media
Treatment by Pathogen
Pathogen |
Clinical Success Rates |
BIAXIN |
Oral Cephalosporin |
S. pneumoniae |
13/15 (87%) |
4/5 |
H. influenzaea |
10/14 (71%) |
3/4 |
M. catarrhalis |
4/5 |
1/1 |
S. pyogenes |
3/3 |
0/1 |
All Pathogens Combined |
30/37 (81%) |
8/11 (73%) |
a None of the H. influenzae isolated
pre-treatment was resistant to BIAXIN; 6% were resistant to the control agent. |
Otitis Media Trials Of BIAXIN vs.
Antimicrobial/Beta-lactamase Inhibitor
In two other controlled clinical trials of acute otitis
media performed in the United States, where significant rates of beta-lactamase
producing organisms were found, BIAXIN was compared to an oral antimicrobial
agent that contained a specific beta-lactamase inhibitor. In these trials,
strict evaluability criteria were used to determine the clinical responses. In
the 233 patients who were evaluated for clinical efficacy, the combined
clinical success rate (i.e., cure and improvement) at the post-therapy visit
was 91% for both BIAXIN and the control.
For the patients who had microbiologic determinations at
the pre-treatment visit, the presumptive bacterial eradication/clinical cure
outcomes (i.e., clinical success) are shown in Table 17.
Table 17: Clinical Success Rates of Acute Otitis Media
Treatment by Pathogen
PATHOGEN |
Clinical Success Rates |
BIAXIN |
Antimicrobial/Beta-lactamase Inhibitor |
S. pneumoniae |
43/51 (84%) |
55/56 (98%) |
H. influenzaea |
36/45 (80%) |
31/33 (94%) |
M. catarrhalis |
9/10 (90%) |
6/6 |
S. pyogenes |
3/3 |
5/5 |
All Pathogens Combined |
91/109 (83%) |
97/100 (97%) |
a Of the H. influenzae isolated
pre-treatment, 3% were resistant to BIAXIN and 10% were resistant to the
control agent. |
H. pylori Eradication To Decrease The Risk Of Duodenal
Ulcer Recurrence
BIAXIN + Lansoprazole And Amoxicillin
Two U.S. randomized, double-blind clinical trials (trial
6 and trial 7) in patients with H. pylori and duodenal ulcer disease
(defined as an active ulcer or history of an active ulcer within one year)
evaluated the efficacy of BIAXIN 500 mg twice daily in combination with
lansoprazole 30 mg twice daily and amoxicillin 1 gm twice daily as 14-day
triple therapy for eradication of H. pylori.
H. pylori eradication was defined as two negative
tests (culture and histology) at 4 weeks to 6 weeks following the end of
treatment.
The combination of BIAXIN plus lansoprazole and amoxicillin
as triple therapy was effective in eradication of H. pylori (see results
in Table 18). Eradication of H. pylori has been shown to reduce the risk
of duodenal ulcer recurrence.
A randomized, double-blind clinical trial (trial 8)
performed in the U.S. in patients with H. pylori and duodenal ulcer
disease (defined as an active ulcer or history of an ulcer within one year)
compared the efficacy of BIAXIN in combination with lansoprazole and
amoxicillin as triple therapy for 10 days and 14 days. This trial established
that the 10-day triple therapy was equivalent to the 14-day triple therapy in
eradicating H. pylori (see results in Table 18).
Table 18: H. pylori Eradication Rates-Triple
Therapy (BIAXIN/lansoprazole/amoxicillin) Percent of Patients Cured [95%
Confidence Interval] (number of patients)
Trial |
Duration |
Triple Therapy Evaluable Analysisa |
Triple Therapy Intent-to-Treat Analysisb |
Trial 6 |
14 days |
92c[80-97.7] |
86c [73.3-93.5] |
|
|
(n = 48) |
(n = 55) |
Trial 7 |
14 days |
86d [75.7-93.6]
(n = 66) |
83d [72-90.8]
(n = 70) |
Trial 8e |
14 days |
85 [77-91]
(N = 113) |
82 [73.9-88.1]
(N = 126) |
|
10 days |
84 [76-89.8]
(N = 123) |
81 [73.9-87.6]
(N = 135) |
a Based on evaluable patients with confirmed
duodenal ulcer (active or within one year) and H. pylori infection at
baseline defined as at least two of three positive endoscopic tests from
CLOtest (Delta West LTD., Bentley, Australia), histology, and/or culture.
Patients were included in the analysis if they completed the trial.
Additionally, if patients were dropped out of the trial due to an adverse
reaction related to the drug, they were included in the analysis as evaluable
failures of therapy.
b Patients were included in the analysis if they had documented H.
pylori infection at baseline as defined above and had a confirmed duodenal
ulcer (active or within one year). All dropouts were included as failures of
therapy.
c (p < 0.05) versus BIAXIN/lansoprazole and
lansoprazole/amoxicillin dual therapy.
d (p < 0.05) versus BIAXIN/amoxicillin dual
therapy.
e The 95% confidence interval for the difference in eradication
rates, 10-day minus 14-day, is (10.5, 8.1) in the evaluable analysis and (-9.7,
9.1) in the intent-to-treat analysis. |
BIAXIN + Omeprazole And Amoxicillin Therapy
Three U.S., randomized, double-blind clinical trials in
patients with H. pylori infection and duodenal ulcer disease (n = 558)
compared BIAXIN plus omeprazole and amoxicillin to BIAXIN plus amoxicillin. Two
trials (trials 9 and 10) were conducted in patients with an active duodenal
ulcer, and the third trial (trial 11) was conducted in patients with a duodenal
ulcer in the past 5 years, but without an ulcer present at the time of
enrollment. The dosage regimen in the trials was BIAXIN 500 mg twice a day plus
omeprazole 20 mg twice a day plus amoxicillin 1 gram twice a day for 10 days.
In trials 9 and 10, patients who took the omeprazole regimen also received an
additional 18 days of omeprazole 20 mg once a day. Endpoints studied were
eradication of H. pylori and duodenal ulcer healing (trials 9 and 10
only). H. pylori status was determined by CLOtest®, histology, and
culture in all three trials. For a given patient, H. pylori was
considered eradicated if at least two of these tests were negative, and none
was positive. The combination of BIAXIN plus omeprazole and amoxicillin was
effective in eradicating H. pylori (see results in Table 19).
Table 19: H. pylori Eradication Rates: % of
Patients Cured [95% Confidence Interval]
|
BIAXIN + omeprazole + amoxicillin |
BIAXIN + amoxicillin |
Per-Protocola |
Intent-to-Treatb |
Per-Protocola |
Intent-to-Treatb |
Trial 9 |
c77 [64, 86] (n = 64) |
69 [57, 79]
(n = 80) |
43 [31, 56]
(n = 67) |
37 [27, 48]
(n = 84) |
Trial 10 |
c78 [67, 88] (n = 65) |
73 [61, 82]
(n = 77) |
41 [29, 54]
(n = 68) |
36 [26, 47]
(n = 84) |
Trial 11 |
c90 [80, 96] |
83 [74, 91] |
33 [24, 44] |
32 [23, 42] |
a Patients were included in the analysis if
they had confirmed duodenal ulcer disease (active ulcer trials 9 and 10;
history of ulcer within 5 years, trial 11) and H. pylori infection at
baseline defined as at least two of three positive endoscopic tests from
CLOtest®, histology, and/or culture. Patients were included in the analysis if
they completed the trial. Additionally, if patients dropped out of the trial
due to an adverse reaction related to the study drug, they were included in the
analysis as failures of therapy. The impact of eradication on ulcer recurrence
has not been assessed in patients with a past history of ulcer.
b Patients were included in the analysis if they had documented H.
pylori infection at baseline and had confirmed duodenal ulcer disease. All
dropouts were included as failures of therapy.
c p < 0.05 versus BIAXIN plus amoxicillin. |
BIAXIN + Omeprazole Therapy
Four randomized, double-blind, multi-center trials
(trials 12, 13, 14, and 15) evaluated BIAXIN 500 mg three times a day plus
omeprazole 40 mg once a day for 14 days, followed by omeprazole 20 mg once a
day (trials 12, 13, and 15) or by omeprazole 40 mg once a day (trial 14) for an
additional 14 days in patients with active duodenal ulcer associated with H.
pylori. Trials 12 and 13 were conducted in the U.S. and Canada and enrolled
242 and 256 patients, respectively. H. pylori infection and duodenal
ulcer were confirmed in 219 patients in trial 12 and 228 patients in trial 13.
These trials compared the combination regimen to omeprazole and BIAXIN
monotherapies. Trials 14 and 15were conducted in Europe and enrolled 154 and
215 patients, respectively. H. pylori infection and duodenal ulcer were
confirmed in 148 patients in trial 14 and 208 patients in trial 15. These
trials compared the combination regimen to omeprazole monotherapy. The results
for the efficacy analyses for these trials are described in Tables 20, 21, and
22.
Duodenal Ulcer Healing
The combination of BIAXIN and omeprazole was as effective
as omeprazole alone for healing duodenal ulcer (see Table 20).
Table 20: End-of-Treatment Ulcer Healing Rates Percent
of Patients Healed (n/N)
Trial |
BIAXIN + Omeprazole |
Omeprazole |
BIAXIN |
U.S. Trials |
Trial 13 |
94% (58/62)a |
88% (60/68) |
71% (49/69) |
Trial 12 |
88% (56/64)a |
85% (55/65) |
64% (44/69) |
Non-U.S. Trials |
Trial 15 |
99% (84/85) |
95% (82/86) |
N/A |
Trial 14b |
100% (64/64) |
99% (71/72) |
N/A |
a p < 0.05 for BIAXIN + omeprazole versus
BIAXIN monotherapy.
b In trial 14 patients received omeprazole 40 mg daily for days 15
to 28. |
Eradication Of H. pylori Associated With Duodenal
Ulcer
The combination of BIAXIN and omeprazole was effective in
eradicating H. pylori (see Table 21). H. pylori eradication was
defined as no positive test (culture or histology) at 4 weeks following the end
of treatment, and two negative tests were required to be considered eradicated.
In the per-protocol analysis, the following patients were excluded: dropouts, patients
with major protocol violations, patients with missing H. pylori tests
post-treatment, and patients that were not assessed for H. pylori eradication
at 4 weeks after the end of treatment because they were found to have an
unhealed ulcer at the end of treatment.
Table 21: H. pylori Eradication Rates
(Per-Protocol Analysis) at 4 to 6 weeks Percent of Patients Cured (n/N)
Trial |
BIAXIN + Omeprazole |
Omeprazole |
BIAXIN |
U.S. Trials |
Trial 13 |
64% (39/61)ab |
0% (0/59) |
39% (17/44) |
Trial 12 |
74% (39/53)a,b |
0% (0/54) |
31% (13/42) |
Non-U.S. Trials |
Trial 15 |
74% (64/86)b |
1% (1/90) |
N/A |
Trial 14 |
83% (50/60)b |
1% (1/74) |
N/A |
a Statistically significantly higher than
BIAXIN monotherapy (p < 0.05).
b Statistically significantly higher than omeprazole monotherapy (p
< 0.05). |
Duodenal Ulcer Recurrence
Ulcer recurrence at 6-months and at 12 months following
the end of treatment was assessed for patients in whom ulcers were healed
post-treatment (see the results in Table 22). Thus, in patients with duodenal ulcer
associated with H. pylori infection, eradication of H. pylori reduced
ulcer recurrence.
Table 22: Duodenal Ulcer Recurrence at 6 months and 12
months in Patients with Healed Ulcers
|
H. pylori Negative at 4-6 Weeks |
H. pylori Positive at 4-6 Weeks |
U.S. Trials Recurrence at 6 Months |
Trial 100 |
BIAXIN + Omeprazole |
6% (2/34) |
56% (9/16) |
Omeprazole |
(0/0) |
71% (35/49) |
BIAXIN |
12% (2/17) |
32% (7/22) |
Trial 067 |
BIAXIN + Omeprazole |
38% (11/29) |
50% (6/12) |
Omeprazole |
(0/0) |
67% (31/46) |
BIAXIN |
18% (2/11) |
52% (14/27) |
Non-U.S. Trials Recurrence at 6 Months |
Trial 058 |
BIAXIN + Omeprazole |
6% (3/53) |
24% (4/17) |
Omeprazole |
0% (0/3) |
55% (39/71) |
Trial 812b |
|
|
BIAXIN + Omeprazole |
5% (2/42) |
0% (0/7) |
Omeprazole |
0% (0/1) |
54% (32/59) |
Non-U.S. Trials Recurrence at 12-Months in Trial 14 |
BIAXIN + Omeprazole |
3% (1/40) |
0% (0/6) |
Omeprazole |
0% (0/1) |
67% (29/43) |
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