EZETIMIBE Tablet Ref.[51696] Active ingredients: Ezetimibe

Ezetimibe reduces total cholesterol (total-C), LDL-C, apolipoprotein (Apo) B, and non-high-density lipoprotein cholesterol (non-HDL-C) in patients with hyperlipidemia.

In a 2-week clinical trial in 18 hypercholesterolemic patients, ezetimibe inhibited intestinal cholesterol absorption by 54%, compared with placebo. Ezetimibe had no clinically meaningful effect on the plasma concentrations of the fat-soluble vitamins A, D, and E (in a trial of 113 patients) and did not impair adrenocortical steroid hormone production (in a trial of 118 patients).

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 ezetimibe to fasted adults, mean ezetimibe peak plasma concentrations (C_max) of 3.4 to 5.5 ng/mL were attained within 4 to 12 hours (T_max).

Ezetimibe-glucuronide mean C_max values of 45 to 71 ng/mL were achieved between 1 and 2 hours (T_max). There was no substantial deviation from dose proportionality between 5 and 20 mg. The absolute bioavailability of ezetimibe cannot be determined, as the compound is virtually insoluble in aqueous media suitable for injection.

Effect of Food

Concomitant food administration (high-fat or non-fat meals) had no effect on the extent of absorption of ezetimibe when administered as ezetimibe 10-mg tablets. The C_max value of ezetimibe was increased by 38% with consumption of high-fat meals.

Distribution

Ezetimibe and ezetimibe-glucuronide are highly bound (>90%) to human plasma proteins.

Elimination

Metabolism

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 ezetimibe-glucuronide 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 ezetimibe-glucuronide. Plasma concentration-time profiles exhibit multiple peaks, suggesting enterohepatic recycling.

Excretion

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 trial 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. However, the difference in plasma concentrations is not clinically meaningful.

Gender

In a multiple-dose trial with ezetimibe given 10 mg once daily for 10 days, plasma concentrations for total ezetimibe were slightly higher (<20%) in females than in males.

Race

Based on a meta-analysis of multiple-dose pharmacokinetic studies, there were no pharmacokinetic differences between Black and White subjects. Studies in Asian subjects indicated that the pharmacokinetics of ezetimibe were similar to those seen in White subjects.

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 m ²), the mean AUC values for total ezetimibe, ezetimibe-glucuronide, and ezetimibe were increased approximately 1.5-fold, compared to healthy subjects (n=9).

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 trial (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 [see Use in Specific Populations (8.7)].

Drug Interactions

Ezetimibe 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” trial 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:

^* Based on 10-mg dose of ezetimibe.
^† Post-renal transplant patients with mild impaired or normal renal function. In a different trial, 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 (7).
^§ Supralox, 20 mL.

TABLE 5. Effect of Ezetimibe Coadministration on Systemic Exposure to Other Drugs:

^* See Drug Interactions (7).

A 104-week dietary carcinogenicity study with ezetimibe was conducted in rats at doses up to 1,500 mg/kg/day (males) and 500 mg/kg/day (females) (~20 X the human exposure at 10 mg daily based on AUC_0-24hr for total ezetimibe). A 104-week dietary carcinogenicity study with ezetimibe was also conducted in mice at doses up to 500 mg/kg/day (>150 X the human exposure at 10 mg daily based on AUC_0-24hr for total ezetimibe). There were no statistically significant increases in tumor incidences in drug-treated rats or mice.

No evidence of mutagenicity was observed in vitro in a microbial mutagenicity (Ames) test with Salmonella typhimurium and Escherichia coli with or without metabolic activation. No evidence of clastogenicity was observed in vitro in a chromosomal aberration assay in human peripheral blood lymphocytes with or without metabolic activation. In addition, there was no evidence of genotoxicity in the in vivo mouse micronucleus test.

In oral (gavage) fertility studies of ezetimibe conducted in rats, there was no evidence of reproductive toxicity at doses up to 1,000 mg/kg/day in male or female rats (~7 X the human exposure at 10 mg daily based on AUC_0-24hr for total ezetimibe).

Primary Hyperlipidemia in Adults

Ezetimibe reduces total-C, LDL-C, Apo B, and non-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 trials in 1719 patients (age range 18 to 86 years, 52% females; 91% White, 5% Black or African American, 1% Asian, 3% other races mostly identified as Hispanic or Latino ethnicity) with primary hyperlipidemia, ezetimibe significantly lowered total-C, LDL-C, Apo B, and non-HDL-C compared to placebo (see Table 7). Reduction in LDL-C was consistent across age, sex, and baseline LDL-C.

TABLE 7. Response to Ezetimibe in Patients with Primary Hyperlipidemia (Mean* % Change from Untreated Baseline^†):

^† Baseline – on no lipid-lowering drug.
^‡ Ezetimibe significantly reduced total-C, LDL-C, Apo B, and non-HDL-C compared to placebo.

Combination with Statins: Ezetimibe Added to On-going Statin Therapy

In a multicenter, double-blind, placebo-controlled, 8-week trial, 769 patients (age range 22 to 85 years, 42% females; 90% White, 6% Black or African American, 1% Asian, 3% other races; and 2% identified as Hispanic or Latino ethnicity) 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 ezetimibe or placebo in addition to their on-going statin.

Ezetimibe, added to on-going statin therapy, significantly lowered total-C, LDL-C, Apo B, and non-HDL-C compared with a statin administered alone (see Table 8). LDL-C reductions induced by ezetimibe were generally consistent across all statins.

TABLE 8. Response to Addition of Ezetimibe to On-Going Statin Therapy* in Patients with Hyperlipidemia (Mean % Change from Treated Baseline ^‡):

^* Patients receiving each statin: 40% atorvastatin, 31% simvastatin, 29% others (pravastatin, fluvastatin, cerivastatin, lovastatin).
^‡ Baseline – on a statin alone.
^§ Ezetimibe + statin significantly reduced total-C, LDL-C, Apo B, and non-HDL-C compared to statin alone.

Combination with Statins: Ezetimibe Initiated Concurrently with a Statin

In four multicenter, double-blind, placebo-controlled, 12-week trials, in 2,382 patients (age range 18 to 87 years, 57% female; 88% White, 5% Black or African American, 2% Asian, 5% other races mostly identified as Hispanic or Latino) with hyperlipidemia, ezetimibe or placebo was administered alone or with various doses of atorvastatin, simvastatin, pravastatin, or lovastatin.

When all patients receiving ezetimibe with a statin were compared to all those receiving the corresponding statin alone, ezetimibe significantly lowered total-C, LDL-C, Apo B, and non-HDL-C compared to the statin administered alone. LDL-C reductions induced by ezetimibe were generally consistent across all statins. (See footnote ^‡, Tables 9 to 12.)

TABLE 9. Response to Ezetimibe and Atorvastatin Initiated Concurrently in Patients with Primary Hyperlipidemia (Mean % Change from Untreated Baseline^†):

^† Baseline – on no lipid-lowering drug.
^‡ Ezetimibe + all doses of atorvastatin pooled (10 to 80 mg) significantly reduced total-C, LDL-C, Apo B, and non-HDL-C compared to all doses of atorvastatin pooled (10 to 80 mg).

TABLE 10. Response to Ezetimibe and Simvastatin Initiated Concurrently in Patients with Primary Hyperlipidemia (Mean % Change from Untreated Baseline^†):

^† Baseline – on no lipid-lowering drug.
^‡ Ezetimibe + all doses of simvastatin pooled (10 to 80 mg) significantly reduced total-C, LDL-C, Apo B, and non-HDL-C compared to all doses of simvastatin pooled (10 to 80 mg).

TABLE 11. Response to Ezetimibe and Pravastatin Initiated Concurrently in Patients with Primary Hyperlipidemia (Mean % Change from Untreated Baseline^†):

^† Baseline – on no lipid-lowering drug.
^‡ Ezetimibe + all doses of pravastatin pooled (10 to 40 mg) significantly reduced total-C, LDL-C, Apo B, and non-HDL-C compared to all doses of pravastatin pooled (10 to 40 mg).

TABLE 12. Response to Ezetimibe and Lovastatin Initiated Concurrently in Patients with Primary Hyperlipidemia (Mean % Change from Untreated Baseline^†):

^† Baseline – on no lipid-lowering drug.
^‡ Ezetimibe + all doses of lovastatin pooled (10 to 40 mg) significantly reduced total-C, LDL-C, Apo B, and non-HDL-C compared to all doses of lovastatin pooled (10 to 40 mg).

Combination with Fenofibrate

In a multicenter, double-blind, placebo-controlled, clinical trial in patients with mixed hyperlipidemia, 625 patients (age range 20 to 76 years, 44% female; 79% White, 1% Black or African American, 20% other races; and 11% identified as Hispanic or Latino ethnicity) were treated for up to 12 weeks and 576 for up to an additional 48 weeks. Patients were randomized to receive placebo, ezetimibe alone, 160 mg fenofibrate alone, or ezetimibe and 160 mg fenofibrate in the 12-week trial. After completing the 12-week trial, eligible patients were assigned to ezetimibe coadministered with fenofibrate or fenofibrate monotherapy for an additional 48 weeks.

Ezetimibe coadministered with fenofibrate significantly lowered total-C, LDL-C, Apo B, and non-HDL-C compared to fenofibrate administered alone (see Table 13).

TABLE 13. Response to Ezetimibe and Fenofibrate Initiated Concurrently in Patients with Mixed Hyperlipidemia (Mean % Change from Untreated Baseline^† at 12 weeks):

^† Baseline – on no lipid-lowering drug.

The changes in lipid endpoints after an additional 48 weeks of treatment with ezetimibe coadministered with fenofibrate or with fenofibrate alone were consistent with the 12-week data displayed above.

HeFH in Pediatric Patients

The effects of ezetimibe coadministered with simvastatin (n=126) compared to simvastatin monotherapy (n=122) have been evaluated in males and females with HeFH. In a multicenter, double-blind, controlled trial followed by an open-label phase, 142 males and 106 postmenarchal females, 10 to 17 years of age (mean age 14.2 years, 43% females, 82% White, 4% Asian, 2% Black or African American, 13% multi-racial; 14% identified as Hispanic or Latino ethnicity) with HeFH were randomized to receive either ezetimibe coadministered with simvastatin or simvastatin monotherapy. Inclusion in the trial required 1) a baseline LDL-C level between 160 and 400 mg/dL and 2) a medical history and clinical presentation consistent with HeFH. The mean baseline LDL-C value was 225 mg/dL (range: 161 to 351 mg/dL) in the ezetimibe coadministered with simvastatin group compared to 219 mg/dL (range: 149 to 336 mg/dL) in the simvastatin monotherapy group. The patients received coadministered ezetimibe and simvastatin (10 mg, 20 mg, or 40 mg) or simvastatin monotherapy (10 mg, 20 mg, or 40 mg) for 6 weeks, coadministered ezetimibe and 40 mg simvastatin or 40 mg simvastatin monotherapy for the next 27 weeks, and open-label coadministered ezetimibe and simvastatin (10 mg, 20 mg, or 40 mg) for 20 weeks thereafter.

The results of the trial at Week 6 are summarized in Table 14. Results at Week 33 were consistent with those at Week 6.

TABLE 14. Mean Percent Difference at Week 6 Between the Pooled Ezetimibe Coadministered with Simvastatin Group and the Pooled Simvastatin Monotherapy Group in Adolescent Patients with HeFH:

HoFH in Adults and Pediatric Patients

A trial was conducted to assess the efficacy of ezetimibe in the treatment of HoFH. This double-blind, randomized, 12-week trial enrolled 50 patients (age range 11 to 74 years, 58% female; 90% White, 2% Black or African American, 8% other races identified as Hispanic or Latino) 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), ezetimibe administered with atorvastatin or simvastatin (40 mg), or ezetimibe administered with atorvastatin or simvastatin (80 mg). Due to decreased bioavailability of ezetimibe in patients concomitantly receiving cholestyramine [see Drug Interactions (7)], 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 ezetimibe plus atorvastatin 40 or 80 mg or simvastatin 40 or 80 mg. ezetimibe, 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 ezetimibe plus 80 mg atorvastatin or with ezetimibe plus 80 mg simvastatin, LDL-C was reduced by 27%.

Homozygous Sitosterolemia (Phytosterolemia) in Adults and Pediatric Patients

A trial was conducted to assess the efficacy of ezetimibe in the treatment of homozygous sitosterolemia. In this multicenter, double-blind, placebo-controlled, 8-week trial, 37 patients (age range 9 to 72 years, 65% females; 89% White, 3% Asian, 8% other races identified as Hispanic or Latino) with homozygous sitosterolemia 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 ezetimibe (n=30) or placebo (n=7). Due to decreased bioavailability of ezetimibe in patients concomitantly receiving cholestyramine [see Drug Interactions (7)], ezetimibe was dosed at least 2 hours before or 4 hours after resins were administered. Excluding the one subject receiving LDL apheresis, ezetimibe 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 ezetimibe, mean plasma levels of plant sterols were reduced progressively over the course of the trial. Reductions in sitosterol and campesterol were consistent between patients taking ezetimibe concomitantly with bile acid sequestrants (n=8) and patients not on concomitant bile acid sequestrant therapy (n=21).