Avandaryl
Generic Name: rosiglitazone maleate and glimepiride
Dosage Form: Tablets
WARNING: CONGESTIVE HEART FAILURE
Thiazolidinediones, including rosiglitazone, cause
or exacerbate congestive heart failure in some patients (see WARNINGS,
Rosiglitazone). After initiation of Avandaryl, and after dose increases,
observe patients carefully for signs and symptoms of heart failure
(including excessive, rapid weight gain, dyspnea, and/or edema). If
these signs and symptoms develop, the heart failure should be managed
according to current standards of care. Furthermore, discontinuation
or dose reduction of Avandaryl must be considered.
Avandaryl Description
Avandaryl (rosiglitazone maleate and glimepiride)
tablets contain 2 oral antidiabetic drugs used in the management of
type 2 diabetes: Rosiglitazone maleate and glimepiride.
Rosiglitazone maleate is an oral antidiabetic agent
of the thiazolidinedione class which acts primarily by increasing
insulin sensitivity. Rosiglitazone maleate is not chemically or functionally
related to the sulfonylureas, the biguanides, or the alpha-glucosidase
inhibitors. Chemically, rosiglitazone maleate is (±)-5-[[4-[2-(methyl-2-pyridinylamino)
ethoxy]phenyl] methyl]-2,4-thiazolidinedione, (Z)-2-butenedioate (1:1) with a molecular
weight of 473.52 (357.44 free base). The molecule has a single chiral
center and is present as a racemate. Due to rapid interconversion,
the enantiomers are functionally indistinguishable. The molecular
formula is C18H19N3O3S•C4H4O4. Rosiglitazone maleate is a white
to off-white solid with a melting point range of 122° to 123°C.
The pKa values of rosiglitazone maleate are 6.8 and 6.1.
It is readily soluble in ethanol and a buffered aqueous solution with
pH of 2.3; solubility decreases with increasing pH in the physiological
range. The structural formula of rosiglitazone maleate is:

Glimepiride is an oral antidiabetic drug of the sulfonylurea
class. Glimepiride is a white to yellowish-white, crystalline, odorless
to practically odorless powder. Chemically, glimepiride is 1 - [[p - [2 - (3 - ethyl - 4 - methyl - 2 - oxo - 3 - pyrroline - 1 - carboxamido)ethyl]phenyl]sulfonyl] - 3 - (trans - 4 - methylcyclohexyl)urea
with a molecular weight of 490.62. The molecular formula for glimepiride
is C24H34N4O5S. Glimepiride
is practically insoluble in water. The structural formula of glimepiride
is:

Avandaryl is available for oral
administration as tablets containing rosiglitazone maleate and glimepiride,
respectively, in the following strengths (expressed as rosiglitazone
maleate/glimepiride): 4 mg/1 mg, 4 mg/2 mg, 4 mg/4 mg, 8 mg/2 mg,
and 8 mg/4 mg. Each tablet contains the following inactive ingredients:
Hypromellose 2910, lactose monohydrate, macrogol (polyethylene glycol),
magnesium stearate, microcrystalline cellulose, sodium starch glycolate,
titanium dioxide, and 1 or more of the following: Yellow, red, or
black iron oxides.
Avandaryl - Clinical Pharmacology
Mechanism of Action
Avandaryl combines
2 antidiabetic agents with complementary mechanisms of action to improve
glycemic control in patients with type 2 diabetes: Rosiglitazone
maleate, a member of the thiazolidinedione class, and glimepiride,
a member of the sulfonylurea class. Thiazolidinediones are insulin-sensitizing
agents that act primarily by enhancing peripheral glucose utilization,
whereas sulfonylureas act primarily by stimulating release of insulin
from functioning pancreatic beta cells.
Rosiglitazone
improves glycemic control by improving insulin sensitivity. Rosiglitazone
is a highly selective and potent agonist for the peroxisome proliferator-activated
receptor-gamma (PPARγ). In humans, PPAR receptors are found
in key target tissues for insulin action such as adipose tissue, skeletal
muscle, and liver. Activation of PPARγ nuclear receptors regulates
the transcription of insulin-responsive genes involved in the control
of glucose production, transport, and utilization. In addition, PPARγ-responsive
genes also participate in the regulation of fatty acid metabolism.
Insulin resistance is a common feature characterizing
the pathogenesis of type 2 diabetes. The antidiabetic activity
of rosiglitazone has been demonstrated in animal models of type 2
diabetes in which hyperglycemia and/or impaired glucose tolerance
is a consequence of insulin resistance in target tissues. Rosiglitazone
reduces blood glucose concentrations and reduces hyperinsulinemia
in the ob/ob obese mouse, db/db diabetic mouse, and fa/fa fatty Zucker
rat.
In animal models, the antidiabetic
activity of rosiglitazone was shown to be mediated by increased sensitivity
to insulin’s action in the liver, muscle, and adipose tissues.
The expression of the insulin-regulated glucose transporter GLUT-4
was increased in adipose tissue. Rosiglitazone did not induce hypoglycemia
in animal models of type 2 diabetes and/or impaired glucose tolerance.
The primary mechanism of action of glimepiride in
lowering blood glucose appears to be dependent on stimulating the
release of insulin from functioning pancreatic beta cells. In addition,
extrapancreatic effects may also play a role in the activity of sulfonylureas
such as glimepiride. This is supported by both preclinical and clinical
studies demonstrating that glimepiride administration can lead to
increased sensitivity of peripheral tissues to insulin. These findings
are consistent with the results of a long-term, randomized, placebo-controlled
trial in which glimepiride therapy improved postprandial insulin/C-peptide
responses and overall glycemic control without producing clinically
meaningful increases in fasting insulin/C-peptide levels. However,
as with other sulfonylureas, the mechanism by which glimepiride lowers
blood glucose during long-term administration has not been clearly
established.
Pharmacokinetics
In a bioequivalence
study of Avandaryl 4 mg/4 mg, the area under the curve (AUC)
and maximum concentration (Cmax) of rosiglitazone following
a single dose of the combination tablet were bioequivalent to rosiglitazone
4 mg concomitantly administered with glimepiride 4 mg under
fasted conditions. The AUC of glimepiride following a single fasted
4 mg/4 mg dose was equivalent to glimepiride concomitantly
administered with rosiglitazone, while the Cmax was 13%
lower when administered as the combination tablet (see Table 1).
Table 1. Pharmacokinetic Parameters for
Rosiglitazone and Glimepiride (n = 28)
|
Rosiglitazone |
Glimepiride |
Parameter (Units) |
Regimen A |
Regimen B |
Regimen A |
Regimen B |
AUC0-inf (ng.hr/mL) |
1,259
(833-2,060)
|
1,253
(756-2,758)
|
1,052
(643-2,117)
|
1,101
(648-2,555)
|
AUC0-t (ng.hr/mL) |
1,231
(810-2,019)
|
1,224
(744-2,654)
|
944
(511-1,898)
|
1,038
(606-2,337)
|
Cmax (ng/mL) |
257
(157-352)
|
251
(77.3-434)
|
151
(63.2-345)
|
173
(70.5-329)
|
T½ (hr) |
3.53
(2.60-4.57)
|
3.54
(2.10-5.03)
|
7.63
(4.42-12.4)
|
5.08
(1.80-11.31)
|
Tmax (hr) |
1.00
(0.48-3.02)
|
0.98
(0.48-5.97)
|
3.02
(1.50-8.00)
|
2.53
(1.00-8.03)
|
AUC = area under
the curve; Cmax = maximum concentration; T½ = terminal
half-life; Tmax = time of maximum concentration.
Regimen A = Avandaryl 4 mg/4 mg
tablet; Regimen B = Concomitant dosing of a rosiglitazone
4 mg tablet AND a glimepiride 4 mg tablet.
Data presented as geometric mean (range), exceptT½ which is presented as arithmetic mean (range) and Tmax, which is presented as median (range).
The
rate and extent of absorption of both the rosiglitazone component
and glimepiride component of Avandaryl when taken with food were equivalent
to the rate and extent of absorption of rosiglitazone and glimepiride
when administered concomitantly as separate tablets with food.
Absorption
The AUC
and Cmax of glimepiride increased in a dose-proportional
manner following administration of Avandaryl 4 mg/1 mg,
4 mg/2 mg, and 4 mg/4 mg. Administration of Avandaryl
in the fed state resulted in no change in the overall exposure of
rosiglitazone; however, the Cmax of rosiglitazone decreased
by 32% compared to the fasted state. There was an increase in both
AUC (19%) and Cmax (55%) of glimepiride in the fed state
compared to the fasted state.
Rosiglitazone
The absolute
bioavailability of rosiglitazone is 99%. Peak plasma concentrations
are observed about 1 hour after dosing. The Cmax and
AUC of rosiglitazone increase in a dose-proportional manner over the
therapeutic dose range.
Glimepiride
After oral administration, glimepiride is completely
(100%) absorbed from the gastrointestinal tract. Studies with single
oral doses in normal subjects and with multiple oral doses in patients
with type 2 diabetes have shown significant absorption of glimepiride
within 1 hour after administration and Cmax at 2 to
3 hours.
Distribution
Rosiglitazone
The mean
(CV%) oral volume of distribution (Vss/F) of rosiglitazone
is approximately 17.6 (30%) liters, based on a population pharmacokinetic
analysis. Rosiglitazone is approximately 99.8% bound to plasma proteins,
primarily albumin.
Glimepiride
After intravenous (IV) dosing in normal subjects,
the volume of distribution (Vd) was 8.8 L (113 mL/kg), and
the total body clearance (CL) was 47.8 mL/min. Protein binding
was greater than 99.5%.
Metabolism
and Excretion
Rosiglitazone
Rosiglitazone is extensively metabolized with no
unchanged drug excreted in the urine. The major routes of metabolism
were N-demethylation and hydroxylation, followed by conjugation with
sulfate and glucuronic acid. All the circulating metabolites are considerably
less potent than parent and, therefore, are not expected to contribute
to the insulin-sensitizing activity of rosiglitazone. In vitro data
demonstrate that rosiglitazone is predominantly metabolized by cytochrome
P450 (CYP) isoenzyme 2C8, with CYP2C9 contributing as a minor pathway.
Following oral or IV administration of [14C]rosiglitazone
maleate, approximately 64% and 23% of the dose was eliminated in the
urine and in the feces, respectively. The plasma half-life of [14C]related material ranged from 103 to 158 hours. The
elimination half-life is 3 to 4 hours and is independent of dose.
Glimepiride
Glimepiride is completely metabolized by oxidative
biotransformation after either an IV or oral dose. The major metabolites
are the cyclohexyl hydroxy methyl derivative (M1) and the carboxyl
derivative (M2). Cytochrome P450 2C9 has been shown to be involved
in the biotransformation of glimepiride to M1. M1 is further metabolized
to M2 by one or several cytosolic enzymes. M1, but not M2, possesses
about ⅓ of the pharmacological activity as compared to its
parent in an animal model; however, whether the glucose-lowering effect
of M1 is clinically meaningful is not clear.
When [14C]glimepiride was given orally, approximately
60% of the total radioactivity was recovered in the urine in 7 days
and M1 (predominant) and M2 accounted for 80 to 90% of that recovered
in the urine. Approximately 40% of the total radioactivity was recovered
in feces and M1 and M2 (predominant) accounted for about 70% of that
recovered in feces. No parent drug was recovered from urine or feces.
After IV dosing in patients, no significant biliary excretion of glimepiride
or its M1 metabolite has been observed.
Special Populations
No pharmacokinetic
data are available for Avandaryl in the following special populations.
Information is provided for the individual components of Avandaryl.
Gender
Rosiglitazone
Results of the population pharmacokinetics analysis
showed that the mean oral clearance of rosiglitazone in female patients
(n = 405) was approximately 6% lower compared to male patients
of the same body weight (n = 642). Combination therapy with
rosiglitazone and sulfonylureas improved glycemic control in both
males and females with a greater therapeutic response observed in
females. For a given body mass index (BMI), females tend to have a
greater fat mass than males. Since the molecular target of rosiglitazone,
PPARγ, is expressed in adipose tissues, this differentiating
characteristic may account, at least in part, for the greater response
to rosiglitazone in combination with sulfonylureas in females. Since
therapy should be individualized, no dose adjustments are necessary
based on gender alone.
Glimepiride
There were no differences between males and females
in the pharmacokinetics of glimepiride when adjustment was made for
differences in body weight.
Geriatric
Rosiglitazone
Results of the population pharmacokinetics analysis
(n = 716 <65 years; n = 331 ≥65 years)
showed that age does not significantly affect the pharmacokinetics
of rosiglitazone.
Glimepiride
Comparison of glimepiride pharmacokinetics in type 2
diabetes patients 65 years and younger with those older than
65 years was performed in a study using a dosing regimen of 6 mg
daily. There were no significant differences in glimepiride pharmacokinetics
between the 2 age groups. The mean AUC at steady state for the older
patients was about 13% lower than that for the younger patients; the
mean weight-adjusted clearance for the older patients was about 11%
higher than that for the younger patients. (See PRECAUTIONS, Geriatric
Use.)
Hepatic
Impairment
Therapy with
Avandaryl should not be initiated if the patient exhibits clinical
evidence of active liver disease or increased serum transaminase levels
(ALT >2.5X upper limit of normal) at baseline (see PRECAUTIONS, Hepatic
Effects).
Rosiglitazone
Unbound oral clearance of rosiglitazone was significantly
lower in patients with moderate to severe liver disease (Child-Pugh
Class B/C) compared to healthy subjects. As a result, unbound Cmax and AUC0-inf were increased 2- and 3-fold, respectively.
Elimination half-life for rosiglitazone was about 2 hours longer in
patients with liver disease, compared to healthy subjects.
Glimepiride
No studies of glimepiride have been conducted in
patients with hepatic insufficiency.
Race
Rosiglitazone
Results of a population pharmacokinetic analysis
including subjects of white, black, and other ethnic origins indicate
that race has no influence on the pharmacokinetics of rosiglitazone.
Glimepiride
No pharmacokinetic studies to assess the effects
of race have been performed, but in placebo-controlled studies of
glimepiride in patients with type 2 diabetes, the antihyperglycemic
effect was comparable in whites (n = 536), blacks (n = 63),
and Hispanics (n = 63).
Renal
Impairment
Rosiglitazone
There are no clinically relevant differences in
the pharmacokinetics of rosiglitazone in patients with mild to severe
renal impairment or in hemodialysis-dependent patients compared to
subjects with normal renal function.
Glimepiride
A single-dose glimepiride, open-label study was
conducted in 15 patients with renal impairment. Glimepiride (3 mg)
was administered to 3 groups of patients with different levels of
mean creatinine clearance (CLcr); (Group I, CLcr = 77.7 mL/min, n = 5), (Group II, CLcr = 27.7 mL/min, n = 3), and (Group
III, CLcr = 9.4 mL/min, n = 7).
Glimepiride was found to be well tolerated in all 3 groups. The results
showed that glimepiride serum levels decreased as renal function decreased.
However, M1 and M2 serum levels (mean AUC values) increased 2.3 and
8.6 times from Group I to Group III. The apparent terminal half-life
(T½) for glimepiride did not change, while the half-lives for
M1 and M2 increased as renal function decreased. Mean urinary excretion
of M1 plus M2 as percent of dose, however, decreased (44.4%, 21.9%,
and 9.3% for Groups I to III). A multiple-dose titration study was
also conducted in 16 type 2 diabetes patients with renal impairment
using doses ranging from 1 to 8 mg daily for 3 months. The
results were consistent with those observed after single doses. All
patients with a CLcr less than 22 mL/min had adequate
control of their glucose levels with a dosage regimen of only 1 mg
daily. The results from this study suggest that a starting dose of
1 mg glimepiride, as contained in Avandaryl 4 mg/1 mg,
may be given to type 2 diabetes patients with kidney disease,
and the dose may be titrated based on fasting glucose levels.
Pediatric
No pharmacokinetic data from studies in pediatric
subjects are available for Avandaryl.
Rosiglitazone
Pharmacokinetic parameters of rosiglitazone in pediatric
patients were established using a population pharmacokinetic analysis
with sparse data from 96 pediatric patients in a single pediatric
clinical trial including 33 males and 63 females with ages ranging
from 10 to 17 years (weights ranging from 35 to 178.3 kg).
Population mean CL/F and V/F of rosiglitazone were 3.15 L/hr and 13.5
L, respectively. These estimates of CL/F and V/F were consistent with
the typical parameter estimates from a prior adult population analysis.
Glimepiride
The pharmacokinetics of glimepiride (1 mg)
were evaluated in a single-dose study conducted in 30 type 2 diabetic
patients (male = 7; female = 23) between ages
10 and 17 years. The mean AUC0-last (338.8 ± 203.1 ng.hr/mL),
Cmax (102.4 ± 47.7 ng/mL), and T½ (3.1 ± 1.7 hours) were comparable to those previously
reported in adults (AUC0-last 315.2 ± 95.9 ng.hr/mL,
Cmax 103.2 ± 34.3 ng/mL, and T½ 5.3 ± 4.1 hours).
Drug Interactions
Single oral doses
of glimepiride in 14 healthy adult subjects had no clinically significant
effect on the steady-state pharmacokinetics of rosiglitazone. No clinically
significant reductions in glimepiride AUC and Cmax were
observed after repeat doses of rosiglitazone (8 mg once daily) for
8 days in healthy adult subjects.
Rosiglitazone
Drugs that Inhibit, Induce or are Metabolized by Cytochrome
P450
In vitro drug metabolism studies suggest that rosiglitazone
does not inhibit any of the major P450 enzymes at clinically relevant
concentrations. In vitro data demonstrate that rosiglitazone is predominantly
metabolized by CYP2C8, and to a lesser extent, 2C9. An inhibitor of
CYP2C8 (such as gemfibrozil) may decrease the metabolism of rosiglitazone
and an inducer of CYP2C8 (such as rifampin) may increase the metabolism
of rosiglitazone. Therefore, if an inhibitor or an inducer of CYP2C8
is started or stopped during treatment with rosiglitazone, changes
in diabetes treatment may be needed based upon clinical response.
Rosiglitazone (4 mg twice daily) was shown to
have no clinically relevant effect on the pharmacokinetics of nifedipine
and oral contraceptives (ethinyl estradiol and norethindrone), which
are predominantly metabolized by CYP3A4.
Gemfibrozil
Concomitant administration
of gemfibrozil (600 mg twice daily), an inhibitor of CYP2C8,
and rosiglitazone (4 mg once daily) for 7 days increased
rosiglitazone AUC by 127%, compared to the administration of rosiglitazone
(4 mg once daily) alone. Given the potential for dose-related
adverse events with rosiglitazone, a decrease in the dose of rosiglitazone
may be needed when gemfibrozil is introduced (see PRECAUTIONS).
Rifampin
Rifampin administration
(600 mg once a day), an inducer of CYP2C8, for 6 days is reported
to decrease rosiglitazone AUC by 66%, compared to the administration
of rosiglitazone (8 mg) alone (see PRECAUTIONS).1
Glyburide
Rosiglitazone (2 mg twice daily) taken concomitantly
with glyburide (3.75 to 10 mg/day) for 7 days did not alter
the mean steady-state 24-hour plasma glucose concentrations in diabetic
patients stabilized on glyburide therapy. Repeat doses of rosiglitazone
(8 mg once daily) for 8 days in healthy adult Caucasian subjects caused
a decrease in glyburide AUC and Cmax of approximately 30%.
In Japanese subjects, glyburide AUC and Cmax slightly increased
following coadministration of rosiglitazone.
Digoxin
Repeat oral dosing
of rosiglitazone (8 mg once daily) for 14 days did not alter
the steady-state pharmacokinetics of digoxin (0.375 mg once daily)
in healthy volunteers.
Warfarin
Repeat dosing with rosiglitazone had no clinically
relevant effect on the steady-state pharmacokinetics of warfarin enantiomers.
Additional pharmacokinetic studies demonstrated no clinically
relevant effect of acarbose, ranitidine, or metformin on the pharmacokinetics
of rosiglitazone.
Glimepiride
The hypoglycemic
action of sulfonylureas may be potentiated by certain drugs, including
nonsteroidal anti-inflammatory drugs (NSAIDs) and other drugs that
are highly protein bound, such as salicylates, sulfonamides, chloramphenicol,
coumarins, probenecid, monoamine oxidase inhibitors, and beta-adrenergic
blocking agents. When these drugs are administered to a patient receiving
glimepiride, the patient should be observed closely for hypoglycemia.
When these drugs are withdrawn from a patient receiving glimepiride,
the patient should be observed closely for loss of glycemic control.
Certain drugs tend to produce hyperglycemia and may
lead to loss of control. These drugs include the thiazides and other
diuretics, corticosteroids, phenothiazines, thyroid products, estrogens,
oral contraceptives, phenytoin, nicotinic acid, sympathomimetics,
and isoniazid. When these drugs are administered to a patient receiving
glimepiride, the patient should be closely observed for loss of control.
When these drugs are withdrawn from a patient receiving glimepiride,
the patient should be observed closely for hypoglycemia.
Drugs Metabolized by Cytochrome P450
A potential
interaction between oral miconazole and oral hypoglycemic agents leading
to severe hypoglycemia has been reported. Whether this interaction
also occurs with the IV, topical, or vaginal preparations of miconazole
is not known. There is a potential interaction of glimepiride with
inhibitors (e.g. fluconazole) and inducers (e.g., rifampicin) of cytochrome
P450 2C9.
Aspirin
Coadministration
of aspirin (1 g three times daily) and glimepiride led to a 34%
decrease in the mean glimepiride AUC and, therefore, a 34% increase
in the mean CL/F. The mean Cmax had a decrease of 4%. Blood
glucose and serum C-peptide concentrations were unaffected and no
hypoglycemic symptoms were reported.
H2-Receptor Antagonists
Coadministration of either cimetidine (800 mg
once daily) or ranitidine (150 mg twice daily) with a single
4-mg oral dose of glimepiride did not significantly alter the absorption
and disposition of glimepiride, and no differences were seen in hypoglycemic
symptomatology.
Beta-Blockers
Concomitant
administration of propranolol (40 mg three times daily) and glimepiride
significantly increased Cmax, AUC, and T½ of glimepiride
by 23%, 22%, and 15%, respectively, and it decreased CL/F by 18%.
The recovery of M1 and M2 from urine, however, did not change. The
pharmacodynamic responses to glimepiride were nearly identical in
normal subjects receiving propranolol and placebo. Pooled data from
clinical trials in patients with type 2 diabetes showed no evidence
of clinically significant adverse interactions with uncontrolled concurrent
administration of beta-blockers. However, if beta-blockers are used,
caution should be exercised and patients should be warned about the
potential for hypoglycemia.
Warfarin
Concomitant
administration of glimepiride tablets (4 mg once daily) did not
alter the pharmacokinetic characteristics of R- and S-warfarin enantiomers
following administration of a single dose (25 mg) of racemic
warfarin to healthy subjects. No changes were observed in warfarin
plasma protein binding. Glimepiride treatment did result in a slight,
but statistically significant, decrease in the pharmacodynamic response
to warfarin. The reductions in mean area under the prothrombin time
(PT) curve and maximum PT values during glimepiride treatment were
very small (3.3% and 9.9%, respectively) and are unlikely to be clinically
important.
ACE Inhibitors
The responses
of serum glucose, insulin, C-peptide, and plasma glucagon to 2 mg
glimepiride were unaffected by coadministration of ramipril (an ACE
inhibitor) 5 mg once daily in normal subjects. No hypoglycemic
symptoms were reported.
Other
Although
no specific interaction studies were performed, pooled data from clinical
trials showed no evidence of clinically significant adverse interactions
with uncontrolled concurrent administration of aspirin and other salicylates,
H2-receptor antagonists, ACE inhibitors, calcium-channel
blockers, estrogens, fibrates, NSAIDs, HMG CoA reductase inhibitors,
sulfonamides, or thyroid hormone.
Clinical Studies
Drug-Naïve Patients with Type 2 Diabetes Mellitus
In a 28-week, randomized, double-blind clinical
trial, 901 drug-naïve patients with type 2 diabetes inadequately
controlled with diet and exercise alone (baseline mean fasting plasma
glucose [FPG] 211 mg/dL and baseline mean HbA1c 9.1%) were started
on Avandaryl 4 mg/1 mg, rosiglitazone 4 mg, or glimepiride
1 mg. Doses could be increased at 4-week intervals to reach a
target mean daily glucose of ≤110 mg/dL. Patients who
received Avandaryl were randomized to 1 of 2 titration schemes differing
in the maximum total daily dose (4 mg/4 mg or 8 mg/4 mg).
The maximum total daily dose was 8 mg for rosiglitazone monotherapy
and 4 mg for glimepiride monotherapy. All treatments were administered
as a once daily regimen. Improvements in FPG and HbA1c were observed
in patients treated with Avandaryl compared to either rosiglitazone
or glimepiride alone (see Table 2).
Table 2. Glycemic Parameters in a 28-Week Study of Avandaryl
in Drug-Naïve Patients with Type 2 Diabetes Mellitus
|
Glimepiride |
Rosiglitazone |
Avandaryl
4 mg/4 mg
|
Avandaryl
8 mg/4 mg
|
Mean Final Dose |
3.5 mg |
7.5 mg |
4.0 mg/3.2 mg |
6.8 mg/2.9 mg |
N |
221 |
227 |
221 |
214 |
FPG (mg/dL)
[mean (SD)] |
|
|
|
|
Baseline |
211 (70) |
212 (66) |
207 (58) |
214 (61) |
Change from baseline |
-42 (66) |
-57 (58) |
-70 (57) |
-80 (57) |
Treatment difference between |
|
|
|
|
− Avandaryl and glimepiride |
— |
— |
-30* |
-37* |
− Avandaryl and rosiglitazone |
— |
— |
-16* |
-23* |
% of patients with ≥30 mg/dL
decrease from baseline |
56% |
64% |
77% |
85% |
HbA1c (%) [mean
(SD)] |
|
|
|
|
Baseline |
9.0 (1.3) |
9.1 (1.3) |
9.0 (1.3) |
9.2 (1.4) |
Change from baseline |
-1.7 (1.4) |
-1.8 (1.5) |
-2.4 (1.4) |
-2.5 (1.4) |
Treatment difference between |
|
|
|
|
− Avandaryl and glimepiride |
— |
— |
-0.6* |
-0.7* |
− Avandaryl and rosiglitazone |
— |
— |
-0.7* |
-0.8* |
% of patients with ≥0.7% decrease
from baseline |
82% |
76% |
93% |
93% |
% of patients at HbA1c Target <7.0%† |
49% |
46% |
75% |
72% |
*Least squared
means, p<0.0001 compared to monotherapy.
†Response is related to
baseline HbA1c.
Treatment with Avandaryl
resulted in statistically significant improvements in FPG and HbA1c
compared with each of the monotherapies. However, when considering
choice of therapy for drug-naïve patients, the risk-benefit of
initiating monotherapy or dual therapy should be considered. In particular,
the risk of hypoglycemia and weight gain with dual therapy should
be taken into account. (See WARNINGS, PRECAUTIONS, and ADVERSE REACTIONS.)
The lipid profiles of rosiglitazone and glimepiride
were consistent with the known profile of each monotherapy. Avandaryl
was associated with increases in HDL and LDL (3% to 4% for each) and
decreases in triglycerides (-4%), that were not considered to be clinically
meaningful.
Patients with Type 2 Diabetes Mellitus Previously Treated with
Sulfonylureas
The safety and efficacy of rosiglitazone added to
a sulfonylurea have been studied in clinical trials in patients with
type 2 diabetes inadequately controlled on sulfonylureas alone.
No clinical trials have been conducted with the fixed-dose combination
of Avandaryl in patients inadequately controlled on a sulfonylurea
or who have initially responded to rosiglitazone alone and require
additional glycemic control.
A total of
3,457 patients with type 2 diabetes participated in ten
24- to 26-week randomized, double-blind, placebo/active-controlled
studies and one 2-year double-blind, active-controlled study in elderly
patients designed to assess the efficacy and safety of rosiglitazone
in combination with a sulfonylurea. Rosiglitazone 2 mg, 4 mg,
or 8 mg daily, was administered either once daily (3 studies)
or in divided doses twice daily (7 studies), to patients inadequately
controlled on a submaximal or maximal dose of sulfonylurea.
In these studies, the combination of rosiglitazone
4 mg or 8 mg daily (administered as single or twice daily
divided doses) and a sulfonylurea significantly reduced FPG and HbA1c
compared to placebo plus sulfonylurea or further up-titration of the
sulfonylurea. Table 3 shows pooled data for 8 studies in which rosiglitazone
added to sulfonylurea was compared to placebo plus sulfonylurea.
Table 3. Glycemic Parameters in 24- to
26-Week Combination Studies of Rosiglitazone Plus Sulfonylurea
|
Twice Daily
Divided Dosing
(5 Studies)
|
Sulfonylurea |
Rosiglitazone 2 mg twice daily + sulfonylurea |
Sulfonylurea |
Rosiglitazone 4 mg twice daily + sulfonylurea |
N |
397 |
497 |
248 |
346 |
FPG (mg/dL) |
|
|
|
|
Baseline (mean) |
204 |
198 |
188 |
187 |
Change from baseline (mean) |
11 |
-29 |
8 |
-43 |
Difference from sulfonylurea alone
(adjusted mean) |
- |
-42* |
- |
-53* |
% of patients with ≥30 mg/dL
decrease from baseline |
17% |
49% |
15% |
61% |
HbA1c (%) |
|
|
|
|
Baseline (mean) |
9.4 |
9.5 |
9.3 |
9.6 |
Change from baseline (mean) |
0.2 |
-1.0 |
0.0 |
-1.6 |
Difference from sulfonylurea alone
(adjusted mean) |
- |
-1.1* |
- |
-1.4* |
% of patients with ≥0.7% decrease
from baseline |
21% |
60% |
23% |
75% |
|
Once Daily Dosing
(3 Studies)
|
Sulfonylurea |
Rosiglitazone 4 mg once daily + sulfonylurea |
Sulfonylurea |
Rosiglitazone 8 mg once daily + sulfonylurea |
N |
172 |
172 |
173 |
176 |
FPG (mg/dL) |
|
|
|
|
Baseline (mean) |
198 |
206 |
188 |
192 |
Change from baseline (mean) |
17 |
-25 |
17 |
-43 |
Difference from sulfonylurea alone
(adjusted mean) |
- |
-47* |
- |
-66* |
% of patients with ≥30 mg/dL
decrease from baseline |
17% |
48% |
19% |
55% |
HbA1c (%) |
|
|
|
|
Baseline (mean) |
8.6 |
8.8 |
8.9 |
8.9 |
Change from baseline (mean) |
0.4 |
-0.5 |
0.1 |
-1.2 |
Difference from sulfonylurea alone
(adjusted mean) |
- |
-0.9* |
- |
-1.4* |
% of patients with ≥0.7% decrease
from baseline |
11% |
36% |
20% |
68% |
*p<0.0001
compared to sulfonylurea alone.
One of the
24- to 26-week studies included patients who were inadequately controlled
on maximal doses of glyburide and switched to 4 mg of rosiglitazone
daily as monotherapy; in this group, loss of glycemic control was
demonstrated, as evidenced by increases in FPG and HbA1c. In a
2-year double-blind study, elderly patients (aged 59 to 89 years)
on half-maximal sulfonylurea (glipizide 10 mg twice daily) were
randomized to the addition of rosiglitazone (n = 115, 4 mg
once daily to 8 mg as needed) or to continued up-titration of
glipizide (n = 110), to a maximum of 20 mg twice daily.
Mean baseline FPG and HbA1c were 157 mg/dL and 7.72%, respectively,
for the rosiglitazone plus glipizide arm and 159 mg/dL and 7.65%,
respectively, for the glipizide up-titration arm. Loss of glycemic
control (FPG ≥180 mg/dL) occurred in a significantly lower
proportion of patients (2%) on rosiglitazone plus glipizide compared
to patients in the glipizide up-titration arm (28.7%). About 78% of
the patients on combination therapy completed the 2 years of
therapy while only 51% completed on glipizide monotherapy. The effect
of combination therapy on FPG and HbA1c was durable over the 2-year
study period, with patients achieving a mean of 132 mg/dL for FPG
and a mean of 6.98% for HbA1c compared to no change on the glipizide
arm.
The pattern of LDL and HDL changes
following therapy with rosiglitazone in combination with sulfonylureas
was generally similar to those seen with rosiglitazone in monotherapy.
Rosiglitazone as monotherapy was associated with increases in total
cholesterol, LDL, and HDL and decreases in free fatty acids. The changes
in triglycerides during therapy with rosiglitazone were variable and
we
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