CLINICAL PHARMACOLOGY
Mechanism Of Action
Ezetimibe reduces blood cholesterol by inhibiting the
absorption of cholesterol by the small intestine. In a 2-week clinical study in
18 hypercholesterolemic patients, ZETIA inhibited intestinal cholesterol absorption
by 54%, compared with placebo. ZETIA had no clinically meaningful effect on the
plasma concentrations of the fat-soluble vitamins A, D, and E (in a study of
113 patients), and did not impair adrenocortical steroid hormone production (in
a study of 118 patients).
The cholesterol content of the liver is derived
predominantly from three sources. The liver can synthesize cholesterol, take up
cholesterol from the blood from circulating lipoproteins, or take up cholesterol
absorbed by the small intestine. Intestinal cholesterol is derived primarily
from cholesterol secreted in the bile and from dietary cholesterol.
Ezetimibe has a mechanism of action that differs from
those of other classes of cholesterol-reducing compounds (statins, bile acid
sequestrants [resins], fibric acid derivatives, and plant stanols). The molecular
target of ezetimibe has been shown to be the sterol transporter, Niemann-Pick
C1-Like 1 (NPC1L1), which is involved in the intestinal uptake of cholesterol
and phytosterols.
Ezetimibe does not inhibit cholesterol synthesis in the
liver, or increase bile acid excretion. Instead, ezetimibe localizes at the
brush border of the small intestine and inhibits the absorption of cholesterol,
leading to a decrease in the delivery of intestinal cholesterol to the liver.
This causes a reduction of hepatic cholesterol stores and an increase in
clearance of cholesterol from the blood; this distinct mechanism is
complementary to that of statins and of fenofibrate [see Clinical Studies].
Pharmacodynamics
Clinical studies have demonstrated that elevated levels
of total-C, LDL-C and Apo B, the major protein constituent of LDL, promote
human atherosclerosis. In addition, decreased levels of HDL-C are associated
with the development of atherosclerosis. Epidemiologic studies have established
that cardiovascular morbidity and mortality vary directly with the level of
total-C and LDL-C and inversely with the level of HDL-C. Like LDL,
cholesterol-enriched triglyceride-rich lipoproteins, including very-low-density
lipoproteins (VLDL), intermediate-density lipoproteins (IDL), and remnants, can
also promote atherosclerosis. The independent effect of raising HDL-C or
lowering TG on the risk of coronary and cardiovascular morbidity and mortality
has not been determined.
ZETIA reduces total-C, LDL-C, Apo B, non-HDL-C, and TG,
and increases HDL-C in patients with hyperlipidemia. Administration of ZETIA
with a statin is effective in improving serum total-C, LDL-C, Apo B, non-HDL-C,
TG, and HDL-C beyond either treatment alone. Administration of ZETIA with fenofibrate
is effective in improving serum total-C, LDL-C, Apo B, and non-HDL-C in
patients with mixed hyperlipidemia as compared to either treatment alone. The
effects of ezetimibe given either alone or in addition to a statin or
fenofibrate on cardiovascular morbidity and mortality have not been established.
Pharmacokinetics
Absorption
After oral administration, ezetimibe is absorbed and
extensively conjugated to a pharmacologically active phenolic glucuronide
(ezetimibe-glucuronide). After a single 10-mg dose of ZETIA to fasted adults,
mean ezetimibe peak plasma concentrations (Cmax) of 3.4 to 5.5 ng/mL were
attained within 4 to 12 hours (Tmax ). Ezetimibe-glucuronide mean Cmax values
of 45 to 71 ng/mL were achieved between 1 and 2 hours (Tmax). There was no
substantial deviation from dose proportionality between 5 and 20 mg. Â The
absolute bioavailability of ezetimibe cannot be determined, as the compound is
virtually insoluble in aqueous media suitable for injection.
Effect Of Food On Oral Absorption
Concomitant food administration (high-fat or non-fat
meals) had no effect on the extent of absorption of ezetimibe when administered
as ZETIA 10-mg tablets. The C value of ezetimibe was increased by 38% with
consumption of high-fat meals. ZETIA can be administered with or without food.
Distribution
Ezetimibe and ezetimibe-glucuronide are highly bound
( > 90%) to human plasma proteins.
Metabolism And Excretion
Ezetimibe is primarily metabolized in the small intestine
and liver via glucuronide conjugation (a phase II reaction) with subsequent
biliary and renal excretion. Minimal oxidative metabolism (a phase I reaction)
has been observed in all species evaluated.
In humans, ezetimibe is rapidly metabolized to
ezetimibe-glucuronide. Ezetimibe and ezetimibeglucuronide are the major
drug-derived compounds detected in plasma, constituting approximately 10 to 20%
and 80 to 90% of the total drug in plasma, respectively. Both ezetimibe and
ezetimibe-glucuronide are eliminated from plasma with a half-life of
approximately 22 hours for both ezetimibe and ezetimibeglucuronide. Plasma
concentration-time profiles exhibit multiple peaks, suggesting enterohepatic recycling.
Following oral administration of 14C-ezetimibe
(20 mg) to human subjects, total ezetimibe (ezetimibe + ezetimibe-glucuronide)
accounted for approximately 93% of the total radioactivity in plasma. After 48 hours,
there were no detectable levels of radioactivity in the plasma.
Approximately 78% and 11% of the administered
radioactivity were recovered in the feces and urine, respectively, over a
10-day collection period. Ezetimibe was the major component in feces and accounted
for 69% of the administered dose, while ezetimibe-glucuronide was the major
component in urine and accounted for 9% of the administered dose.
Specific Populations
Geriatric Patients: In a multiple-dose study with
ezetimibe given 10 mg once daily for 10 days, plasma concentrations for total
ezetimibe were about 2-fold higher in older (≥65 years) healthy subjects compared
to younger subjects.
Pediatric Patients: [See Use in Specific
Populations]
Gender: In a multiple-dose study with ezetimibe
given 10 mg once daily for 10 days, plasma concentrations for total ezetimibe
were slightly higher ( < 20%) in women than in men.
Race: Based on a meta-analysis of multiple-dose
pharmacokinetic studies, there were no pharmacokinetic differences between
Black and Caucasian subjects. Studies in Asian subjects indicated that the
pharmacokinetics of ezetimibe were similar to those seen in Caucasian subjects.
Hepatic Impairment: After a single 10-mg dose of
ezetimibe, the mean AUC for total ezetimibe was increased approximately 1.7-fold
in patients with mild hepatic impairment (Child-Pugh score 5 to 6), compared to
healthy subjects. The mean AUC values for total ezetimibe and ezetimibe were
increased approximately 3- to 4-fold and 5- to 6-fold, respectively, in
patients with moderate (Child-Pugh score 7 to 9) or severe hepatic impairment
(Child-Pugh score 10 to 15). In a 14-day, multiple-dose study (10 mg daily) in
patients with moderate hepatic impairment, the mean AUC values for total
ezetimibe and ezetimibe were increased approximately 4-fold on Day 1 and Day 14
compared to healthy subjects. Due to the unknown effects of the increased
exposure to ezetimibe in patients with moderate or severe hepatic impairment,
ZETIA is not recommended in these patients [see WARNINGS AND PRECAUTIONS].
Renal Impairment: After a single 10-mg dose of
ezetimibe in patients with severe renal disease (n=8; mean CrCl ≥ 30
mL/min/1.73 m²), the mean AUC values for total ezetimibe,
ezetimibe-glucuronide, and ezetimibe were increased approximately 1.5-fold,
compared to healthy subjects (n=9).
Drug Interactions
[See also DRUG INTERACTIONS]
ZETIA had no significant effect on a series of probe
drugs (caffeine, dextromethorphan, tolbutamide, and IV midazolam) known to be
metabolized by cytochrome P450 (1A2, 2D6, 2C8/9 and 3A4) in a “cocktail”
study of twelve healthy adult males. This indicates that ezetimibe is neither
an inhibitor nor an inducer of these cytochrome P450 isozymes, and it is
unlikely that ezetimibe will affect the metabolism of drugs that are
metabolized by these enzymes.
TABLE 4: Effect of Coadministered Drugs on Total
Ezetimibe
Coadministered Drug and Dosing Regimen |
Total Ezetimibe * |
Change in AUC |
Change in Cmax |
Cyclosporine-stable dose required (75-150 mg BID)†,‡ |
↑240% |
↑290% |
Fenofibrate, 200 mg QD, 14 days‡ |
↑48% |
↑64% |
Gemfibrozil, 600 mg BID, 7 days‡ |
↑64% |
↑91% |
Cholestyramine, 4 g BID, 14 days‡ |
↓55% |
↓4% |
Aluminum & magnesium hydroxide combination antacid, single dose§ |
↓4% |
↓30% |
Cimetidine, 400 mg BID, 7 days |
↑6% |
↓30% |
Glipizide, 10 mg, single dose |
↑4% |
↓8% |
Statins |
Lovastatin 20 mg QD, 7 days |
↑9% |
↑3% |
Pravastatin 20 mg QD, 14 days |
↑7% |
↑23% |
Atorvastatin 10 mg QD, 14 days |
↓2% |
↑12% |
Rosuvastatin 10 mg QD, 14 days |
↑13% |
↑18% |
Fluvastatin 20 mg QD, 14 days |
↓19% |
↑7% |
*Based on 10-mg dose of ezetimibe.
† Post-renal transplant patients with mild impaired or normal renal function.
In a different study, a renal transplant patient with severe renal
insufficiency (creatinine clearance of 13.2 mL/min/1.73 m²) who was receiving
multiple medications, including cyclosporine, demonstrated a 12-fold greater
exposure to total ezetimibe compared to healthy subjects.
‡ See DRUG INTERACTIONS.
§ Supralox, 20 mL. |
TABLE 5: Effect of Ezetimibe Coadministration on Systemic
Exposure to Other Drugs
Coadministered Drug and its Dosage Regimen |
Ezetimibe Dosage Regimen |
Change in AUC of Coadministered Drug |
Change in Cmax of Coadministered Drug |
Warfarin. 25-mg single dose on Day 7 |
10 mg QD, 11 days |
↓2% (R-warfarin) |
↑3% (R-warfarin) |
↓4% (S-warfarin) |
↑1% (S-warfarin) |
Digoxin. 0.5-mg single dose |
10 mg QD, 8 days |
↑2% |
↓7% |
Gemfibrozil, 600 mg BID, 7 days* |
10 mg QD, 7 days |
↓1% |
↓11% |
Ethinyl estradiol & Levonorgestrel, QD, 21 days |
10 mg QD, days 8-14 of 21d oral contraceptive cycle |
Ethinyl estradiol 0% |
Ethinyl estradiol ↓9% |
|
|
Levonorgesnel 0% |
Levonorgesirel ↓5% |
Glipizide, 10 mg on Days 1 and 9 |
10 mg QD, days 2-9 |
↓3% |
↓5% |
Fenofibrate, 200 mg QD, 14 days* |
10 mg QD, 14 days |
↑11% |
↑7% |
Cyclosporine, 100-mg single dose Day 7* |
20 mg QD, 8 days |
↑15% |
↑10% |
Statins |
Lovastatin 20 mg QD, 7 days |
10 mg QD, 7 days |
↑19% |
↑3% |
Pravastatin 20 mg QD, 14 days |
10 mg QD, 14 days |
↓20% |
↓24% |
Atorvastatin 10 mg QD, 14 days |
10 mg QD, 14 days |
↓4% |
↑7% |
Rosuvastatin 10 mg QD, 14 days |
10 mg QD, 14 days |
↑19% |
↑17% |
Fluvastatin 20 mg QD, 14 days |
10 mg QD, 14 days |
↓39% |
↓27% |
* See DRUG INTERACTIONS |
Animal Toxicology And/Or Pharmacology
The hypocholesterolemic effect of ezetimibe was evaluated
in cholesterol-fed Rhesus monkeys, dogs, rats, and mouse models of human
cholesterol metabolism. Ezetimibe was found to have an ED50 value of 0.5
μg/kg/day for inhibiting the rise in plasma cholesterol levels in monkeys.
The ED50 values in dogs, rats, and mice were 7, 30, and 700 μg/kg/day,
respectively. These results are consistent with ZETIA being a potent
cholesterol absorption inhibitor.
In a rat model, where the glucuronide metabolite of
ezetimibe (SCH 60663) was administered intraduodenally, the metabolite was as
potent as the parent compound (SCH 58235) in inhibiting the absorption of
cholesterol, suggesting that the glucuronide metabolite had activity similar to
the parent drug.
In 1-month studies in dogs given ezetimibe (0.03 to 300
mg/kg/day), the concentration of cholesterol in gallbladder bile increased ~2-
to 4-fold. However, a dose of 300 mg/kg/day administered to dogs for one year
did not result in gallstone formation or any other adverse hepatobiliary
effects. In a 14-day study in mice given ezetimibe (0.3 to 5 mg/kg/day) and fed
a low-fat or cholesterol-rich diet, the concentration of cholesterol in
gallbladder bile was either unaffected or reduced to normal levels, respectively.
A series of acute preclinical studies was performed to
determine the selectivity of ZETIA for inhibiting cholesterol absorption.
Ezetimibe inhibited the absorption of 14C-cholesterol with no effect
on the absorption of triglycerides, fatty acids, bile acids, progesterone,
ethinyl estradiol, or the fatsoluble vitamins A and D.
In 4- to 12-week toxicity studies in mice, ezetimibe did
not induce cytochrome P450 drug metabolizing enzymes. In toxicity studies, a
pharmacokinetic interaction of ezetimibe with statins (parents or their active
hydroxy acid metabolites) was seen in rats, dogs, and rabbits.
Clinical Studies
Primary Hyperlipidemia
ZETIA reduces total-C, LDL-C, Apo B, non-HDL-C, and TG,
and increases HDL-C in patients with hyperlipidemia. Maximal to near maximal
response is generally achieved within 2 weeks and maintained during chronic
therapy.
Monotherapy
In two multicenter, double-blind, placebo-controlled,
12-week studies in 1719 patients with primary hyperlipidemia, ZETIA
significantly lowered total-C, LDL-C, Apo B, non-HDL-C, and TG, and increased
HDL-C compared to placebo (see Table 6). Reduction in LDL-C was consistent
across age, sex, and baseline LDL-C.
TABLE 6: Response to ZETIA in Patients with Primary
Hyperlipidemia (Mean % Change from Untreated Baseline†)
|
Treatment Group |
N |
T otal-C |
LDL-C |
Apo B |
Non-HDL- C |
TG* |
HDL-C |
Study 1‡ |
Placebo |
205 |
+1 |
+1 |
-1 |
+1 |
-1 |
-1 |
Ezetimibe |
622 |
-12 |
-18 |
-15 |
-16 |
-7 |
+1 |
Study 2‡ |
Placebo |
226 |
+1 |
+1 |
-1 |
+2 |
+2 |
-2 |
Ezetimibe |
666 |
-12 |
-18 |
-16 |
-16 |
-9 |
+1 |
Pooled Data‡ (Studies 1 & 2) |
Placebo |
431 |
0 |
+1 |
-2 |
+1 |
0 |
-2 |
Ezetimibe |
1288 |
-13 |
-18 |
-16 |
-16 |
-8 |
+1 |
*For triglycerides, median % change from baseline.
† Baseline - on no lipid-lowering drug.
‡ ZETIA significantly reduced total-C, LDL-C, Apo B, non-HDL-C, and TG, and
increased HDL-C compared to placebo. |
Combination with Statins
ZETIA Added to On-going Statin Therapy
In a multicenter, double-blind, placebo-controlled,
8-week study, 769 patients with primary hyperlipidemia, known coronary heart
disease or multiple cardiovascular risk factors who were already receiving
statin monotherapy, but who had not met their NCEP ATP II target LDL-C goal
were randomized to receive either ZETIA or placebo in addition to their
on-going statin.
ZETIA, added to on-going statin therapy, significantly
lowered total-C, LDL-C, Apo B, non-HDL-C, and TG, and increased HDL-C compared
with a statin administered alone (see Table 7). LDL-C reductions induced by
ZETIA were generally consistent across all statins.
TABLE 7: Response to Addition of ZETIA to On-Going Statin
Therapy in Patients with Hyperlipidemia (Mean % Change from Treated Baseline‡)
Treatment (Daily Dose) |
N |
Total-C |
LDL-C |
Apo B |
Non- HDL-C |
TG† |
HDL-C |
On-going Statin + Placebo§ |
390 |
-2 |
-4 |
-3 |
-3 |
-3 |
+1 |
On-going Statin + ZETIA§ |
379 |
-17 |
-25 |
-19 |
-23 |
-14 |
+3 |
*Patients receiving each statin: 4 0% atorvastatin, 31%
simvastatin, 29% others (pravastatin, fluvastatin, cerivastatin, lovastatin).
† For triglycerides, median % change from baseline.
‡ Baseline - on a statin alone.
§ ZETIA + statin significantly reduced total-C, LDL-C, Apo B, non-HDL-C, and
TG, and increased HDL-C compared to statin alone. |
ZETIA Initiated Concurrently with a Statin
In four multicenter, double-blind, placebo-controlled,
12-week trials, in 2382 hyperlipidemic patients, ZETIA or placebo was
administered alone or with various doses of atorvastatin, simvastatin,
pravastatin, or lovastatin.
When all patients receiving ZETIA with a statin were
compared to all those receiving the corresponding statin alone, ZETIA
significantly lowered total-C, LDL-C, Apo B, non-HDL-C, and TG, and, with the
exception of pravastatin, increased HDL-C compared to the statin administered
alone. LDL-C reductions induced by ZETIA were generally consistent across all
statins. (See footnote , Tables 8 to 11.)
TABLE 8: Response to ZETIA and Atorvastatin Initiated
Concurrently in Patients with Primary Hyperlipidemia (Mean % Change from
Untreated Baseline†)
Treatment (Daily Dose) |
N |
Total- C |
LDL-C |
Apo B |
Non- HDL-C |
TG* |
HDLC |
Placebo |
60 |
+4 |
+4 |
+3 |
+4 |
-6 |
+4 |
ZETIA |
65 |
-14 |
-20 |
-15 |
-18 |
-5 |
+4 |
Atorvastatin 10 mg |
60 |
-26 |
-37 |
-28 |
-34 |
-21 |
+6 |
ZETIA + Atorvastatin 10 mg |
65 |
-38 |
-53 |
-43 |
-49 |
-31 |
+9 |
Atorvastatin 20 mg |
60 |
-30 |
-42 |
-34 |
-39 |
-23 |
+4 |
ZETIA + Atorvastatin 20 mg |
62 |
-39 |
-54 |
-44 |
-50 |
-30 |
+9 |
Atorvastatin 40 mg |
66 |
-32 |
-45 |
-37 |
-41 |
-24 |
+4 |
ZETIA + Atorvastatin 40 mg |
65 |
-42 |
-56 |
-45 |
-52 |
-34 |
+5 |
Atorvastatin 80 mg |
62 |
-40 |
-54 |
-46 |
-51 |
-31 |
+3 |
ZETIA + Atorvastatin 80 mg |
63 |
-46 |
-61 |
-50 |
-58 |
-40 |
+7 |
Pooled data (All Atorvastatin Doses)‡ |
248 |
-32 |
-44 |
-36 |
-41 |
-24 |
+4 |
Pooled data (All ZETIA + Atorvastatin Doses)‡ |
255 |
-41 |
-56 |
-45 |
-52 |
-33 |
+7 |
*For triglycerides, median % change from baseline.
† Baseline - on no lipid-lowering drug.
‡ ZETIA + all doses of atorvastatin pooled (10–80 mg) significantly reduced
total-C, LDLC, Apo B, non-HDL-C, and TG, and increased HDL-C compared to all
doses of atorvastatin pooled (10–80 mg). |
TABLE 9: Response to ZETIA and Simvastatin Initiated
Concurrently in Patients with Primary Hyperlipidemia (Mean % Change from
Untreated Baseline†)
Treatment (Daily Dose) |
N |
Total- C |
LDL-C |
Apo B |
Non- HDL-C |
TG* |
HDL- C |
Placebo |
70 |
-1 |
-1 |
0 |
-1 |
+2 |
+1 |
ZETIA |
61 |
-13 |
-19 |
-14 |
-17 |
-11 |
+5 |
Simvastatin 10 mg |
70 |
-18 |
-27 |
-21 |
-25 |
-14 |
+8 |
ZETIA + Simvastatin 10 mg |
67 |
-32 |
-46 |
-35 |
-42 |
-26 |
+9 |
Simvastatin 20 mg |
61 |
-26 |
-36 |
-29 |
-33 |
-18 |
+6 |
ZETIA + Simvastatin 20 mg |
69 |
-33 |
-46 |
-36 |
-42 |
-25 |
+9 |
Simvastatin 40 mg |
65 |
-27 |
-38 |
-32 |
-35 |
-24 |
+6 |
ZETIA + Simvastatin 40 mg |
73 |
-40 |
-56 |
-45 |
-51 |
-32 |
+11 |
Simvastatin 80 mg |
67 |
-32 |
-45 |
-37 |
-41 |
-23 |
+8 |
ZETIA + Simvastatin 80 mg |
65 |
-41 |
-58 |
-47 |
-53 |
-31 |
+8 |
Pooled data (All Simvastatin Doses)‡ |
263 |
-26 |
-36 |
-30 |
-34 |
-20 |
+7 |
Pooled data (All ZETIA + Simvastatin Doses)‡ |
274 |
-37 |
-51 |
-41 |
-47 |
-29 |
+9 |
*For triglycerides, median % change from baseline.
† Baseline - on no lipid-lowering drug.
‡ ZETIA + all doses of simvastatin pooled (10–80 mg) significantly reduced
total-C, LDLC, Apo B, non-HDL-C, and TG, and increased HDL-C compared to all
doses of simvastatin pooled (10–80 mg). |
TABLE 10: Response to ZETIA and Pravastatin Initiated
Concurrently in Patients with Primary Hyperlipidemia (Mean % Change from
Untreated Baseline†)
Treatment (Daily Dose) |
N |
Total- C |
LDL-C |
Apo B |
Non- HDL-C |
TG* |
HDL- C |
Placebo |
65 |
0 |
-1 |
-2 |
0 |
-1 |
+2 |
ZETIA |
64 |
-13 |
-20 |
-15 |
-17 |
-5 |
+4 |
Pravastatin 10 mg |
66 |
-15 |
-21 |
-16 |
-20 |
-14 |
+6 |
ZETIA + Pravastatin 10 mg |
71 |
-24 |
-34 |
-27 |
-32 |
-23 |
+8 |
Pravastatin 20 mg |
69 |
-15 |
-23 |
-18 |
-20 |
-8 |
+8 |
ZETIA + Pravastatin 20 mg |
66 |
-27 |
-40 |
-31 |
-36 |
-21 |
+8 |
Pravastatin 40 mg |
70 |
-22 |
-31 |
-26 |
-28 |
-19 |
+6 |
ZETIA + Pravastatin 40 mg |
67 |
-30 |
-42 |
-32 |
-39 |
-21 |
+8 |
Pooled data (All Pravastatin Doses)‡ |
205 |
-17 |
-25 |
-20 |
-23 |
-14 |
+7 |
Pooled data (All ZETIA + Pravastatin Doses)‡ |
204 |
-27 |
-39 |
-30 |
-36 |
-21 |
+8 |
*For triglycerides, median % change from baseline.
† Baseline - on no lipid-lowering drug.
‡ ZETIA + all doses of pravastatin pooled (10–4 0 mg) significantly reduced
total-C, LDLC, Apo B, non-HDL-C, and TG compared to all doses of pravastatin
pooled (10–4 0 mg). |
TABLE 11: Response to ZETIA and Lovastatin Initiated
Concurrently in Patients with Primary Hyperlipidemia (Mean % Change from
Untreated Baseline†)
Treatment (Daily Dose) |
N |
Total- C |
LDL-C |
Apo B |
Non- HDL-C |
TG* |
HDL- C |
Placebo |
64 |
+1 |
0 |
+1 |
+1 |
+6 |
0 |
ZETIA |
72 |
-13 |
-19 |
-14 |
-16 |
-5 |
+3 |
Lovastatin 10 mg |
73 |
-15 |
-20 |
-17 |
-19 |
-11 |
+5 |
ZETIA + Lovastatin 10 mg |
65 |
-24 |
-34 |
-27 |
-31 |
-19 |
+8 |
Lovastatin 20 mg |
74 |
-19 |
-26 |
-21 |
-24 |
-12 |
+3 |
ZETIA + Lovastatin 20 mg |
62 |
-29 |
-41 |
-34 |
-39 |
-27 |
+9 |
Lovastatin 40 mg |
73 |
-21 |
-30 |
-25 |
-27 |
-15 |
+5 |
ZETIA + Lovastatin 40 mg |
65 |
-33 |
-46 |
-38 |
-43 |
-27 |
+9 |
Pooled data (All Lovastatin Doses)‡ |
220 |
-18 |
-25 |
-21 |
-23 |
-12 |
+4 |
Pooled data (All ZETIA + Lovastatin Doses)‡ |
192 |
-29 |
-40 |
-33 |
-38 |
-25 |
+9 |
*For triglycerides, median % change from baseline.
† Baseline - on no lipid-lowering drug.
‡ ZETIA + all doses of lovastatin pooled (10–4 0 mg) significantly reduced
total-C, LDL-C, Apo B, non-HDL-C, and TG, and increased HDL-C compared to all
doses of lovastatin pooled (10–4 0 mg). |
Combination with Fenofibrate
In a multicenter, double-blind, placebo-controlled,
clinical study in patients with mixed hyperlipidemia, 625 patients were treated
for up to 12 weeks and 576 for up to an additional 48 weeks. Patients were randomized
to receive placebo, ZETIA alone, 160-mg fenofibrate alone, or ZETIA and 160-mg fenofibrate
in the 12-week study. After completing the 12-week study, eligible patients
were assigned to ZETIA coadministered with fenofibrate or fenofibrate
monotherapy for an additional 48 weeks.
ZETIA coadministered with fenofibrate significantly
lowered total-C, LDL-C, Apo B, and non-HDL-C compared to fenofibrate
administered alone. The percent decrease in TG and percent increase in HDLC for
ZETIA coadministered with fenofibrate were comparable to those for fenofibrate
administered alone (see Table 12).
TABLE 12: Response to ZETIA and Fenofibrate Initiated
Concurrently in Patients with Mixed Hyperlipidemia (Mean % Change from
Untreated Baseline† at 12 weeks†)
Treatment (Daily Dose) |
N |
Total- C |
LDL-C |
Apo B |
TG* |
HDL- C |
Non- HDL- C |
Placebo |
63 |
0 |
0 |
-1 |
-9 |
+3 |
0 |
ZETIA |
185 |
-12 |
-13 |
-11 |
-11 |
+4 |
-15 |
Fenofibrate 160 mg |
188 |
-11 |
-6 |
-15 |
-43 |
+19 |
-16 |
ZETIA + Fenofibrate 16 0 mg |
183 |
-22 |
-20 |
-26 |
-44 |
+19 |
-30 |
* For triglycerides, median % change from baseline.
† Baseline - on no lipid-lowering drug. |
The changes in lipid endpoints after an additional 48
weeks of treatment with ZETIA coadministered with fenofibrate or with
fenofibrate alone were consistent with the 12-week data displayed above.
Homozygous Familial Hypercholesterolemia (HoFH)
A study was conducted to assess the efficacy of ZETIA in
the treatment of HoFH. This double-blind, randomized, 12-week study enrolled 50
patients with a clinical and/or genotypic diagnosis of HoFH, with or without
concomitant LDL apheresis, already receiving atorvastatin or simvastatin (40
mg). Patients were randomized to one of three treatment groups, atorvastatin or
simvastatin (80 mg), ZETIA administered with atorvastatin or simvastatin (40
mg), or ZETIA administered with atorvastatin or simvastatin (80 mg). Due to
decreased bioavailability of ezetimibe in patients concomitantly receiving cholestyramine
[see DRUG INTERACTIONS], ezetimibe was dosed at least 4 hours before or
after administration of resins. Mean baseline LDL-C was 341 mg/dL in those
patients randomized to atorvastatin 80 mg or simvastatin 80 mg alone and 316
mg/dL in the group randomized to ZETIA plus atorvastatin 40 or 80 mg or
simvastatin 40 or 80 mg. ZETIA, administered with atorvastatin or simvastatin
(40- and 80-mg statin groups, pooled), significantly reduced LDL-C (21%)
compared with increasing the dose of simvastatin or atorvastatin monotherapy
from 40 to 80 mg (7%). In those treated with ZETIA plus 80-mg atorvastatin or
with ZETIA plus 80-mg simvastatin, LDL-C was reduced by 27%.
Homozygous Sitosterolemia (Phytosterolemia)
A study was conducted to assess the efficacy of ZETIA in
the treatment of homozygous sitosterolemia. In this multicenter, double-blind,
placebo-controlled, 8-week trial, 37 patients with homozygoussitosterolemia
with elevated plasma sitosterol levels ( > 5 mg/dL) on their current
therapeutic regimen (diet, bile-acid-binding resins, statins, ileal bypass
surgery and/or LDL apheresis), were randomized to receive ZETIA (n=30) or
placebo (n=7). Due to decreased bioavailability of ezetimibe in patients concomitantly
receiving cholestyramine [see DRUG INTERACTIONS], ezetimibe was dosed at
least 2 hours before or 4 hours after resins were administered. Excluding the
one subject receiving LDL apheresis, ZETIA significantly lowered plasma
sitosterol and campesterol, by 21% and 24% from baseline, respectively. In
contrast, patients who received placebo had increases in sitosterol and campesterol
of 4% and 3% from baseline, respectively. For patients treated with ZETIA, mean
plasma levels of plant sterols were reduced progressively over the course of
the study. The effects of reducing plasma sitosterol and campesterol on
reducing the risks of cardiovascular morbidity and mortality have not been
established.
Reductions in sitosterol and campesterol were consistent
between patients taking ZETIA concomitantly with bile acid sequestrants (n=8)
and patients not on concomitant bile acid sequestrant therapy (n=21).
Limitations Of Use
The effect of ZETIA on cardiovascular morbidity and
mortality has not been determined.