Aptiom

Monotherapy and Adjunctive Therapy

Adult Patients

The recommended initial dosage of APTIOM is 400 mg administered orally once daily. For some patients, treatment may be initiated at 800 mg once daily if the need for seizure reduction outweighs an increased risk of adverse reactions during initiation [see Adverse Reactions ]. Dosage should be increased in weekly increments of 400 mg to 600 mg, based on clinical response and tolerability, to a recommended maintenance dosage of 800 mg to 1600 mg once daily. For patients on APTIOM monotherapy, the 800 mg once daily maintenance dose should generally be considered in patients who are unable to tolerate a 1200 mg daily dose. For patients on APTIOM adjunctive therapy, the 1600 mg daily dose should generally be considered in patients who did not achieve a satisfactory response with a 1200 mg daily dose.

            Pediatric Patients (4 to 17 Years of Age)

           In pediatric patients 4 to 17 years of age, the recommended dosing regimen is dependent upon body weight and is administered orally once daily. The recommended initial dosage of APTIOM is shown in Table 1. Dosage should be increased based on clinical response and tolerability, no more frequently than once per week. Titration increments should not exceed those shown in Table 1. The daily maintenance dosage should not exceed the maintenance dosage for each body weight range shown in Table 1.

Pregnancy Exposure Registry

There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to AEDs, such as APTIOM, during pregnancy. Encourage women who are taking APTIOM during pregnancy to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry by calling 1-888-233-2334 or visiting http://www.aedpregnancyregistry.org.

Risk Summary

Limited available data with APTIOM use in pregnant women are insufficient to inform a drug-associated risk of adverse developmental outcomes. In oral studies conducted in pregnant mice, rats, and rabbits, eslicarbazepine acetate demonstrated developmental toxicity, including increased incidence of malformations (mice), embryolethality (rats), and fetal growth retardation (all species), at clinically relevant doses (see Data). Advise a pregnant woman of the potential risk to a fetus.

In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. The background risk of major birth defects and miscarriage for the indicated population is unknown.

Data

Animal Data

When eslicarbazepine acetate was orally administered (150, 350, 650 mg/kg/day) to pregnant mice throughout organogenesis, increased incidences of fetal malformations was observed at all doses and fetal growth retardation was observed at the mid and high doses. A no-effect dose for adverse developmental effects was not identified. At the lowest dose tested, plasma eslicarbazepine exposure (Cmax, AUC) is less than that in humans at the maximum recommended human dose (MRHD, 1600 mg/day).

Oral administration of eslicarbazepine acetate (40, 160, 320 mg/kg/day) to pregnant rabbits throughout organogenesis resulted in fetal growth retardation and increased incidences of skeletal variations at the mid and high doses. The no-effect dose (40 mg/kg/day) is less than the MRHD on a mg/m2 basis.

Oral administration to pregnant rats (65, 125, 250 mg/kg/day) throughout organogenesis resulted in embryolethality at all doses, increased incidences of skeletal variations at the mid and high doses, and fetal growth retardation at the high dose. The lowest dose tested (65 mg/kg/day) is less than the MRHD on a mg/m2 basis.

When eslicarbazepine acetate was orally administered to female mice during pregnancy and lactation (150, 350, 650 mg/kg/day), the gestation period was prolonged at the highest dose tested. In offspring, a persistent reduction in offspring body weight and delayed physical development and sexual maturation were observed at the mid and high doses. The lowest dose tested (150 mg/kg/day) is less than the MRHD on a mg/m2 basis.

When eslicarbazepine acetate was orally administered (65, 125, 250 mg/kg/day) to rats during pregnancy and lactation, reduced offspring body weight was seen at the mid and high doses. Delayed sexual maturation and a neurological deficit (decreased motor coordination) were observed at the highest dose tested. The no-effect dose for adverse developmental effects (65 mg/kg/day) is less than the MRHD on a mg/m2 basis.

The rat data are of uncertain relevance to humans because of differences in metabolic profile between species.

Contraception

Use of APTIOM with hormonal contraceptives containing ethinylestradiol or levonorgestrel is associated with lower plasma levels of these hormones. Advise women of reproductive potential taking APTIOM who are using a contraceptive containing ethinylestradiol or levonorgestrel to use additional or alternative non-hormonal birth control [see Drug Interactions ].

Infertility

Eslicarbazepine acetate was evaluated in rats and mice for potential adverse impact on fertility of the parental and first generation [see Nonclinical Toxicology ]. In a fertility study in male and female mice, adverse developmental outcomes were observed in embryos. In a fertility study in male and female rats, impairment of female fertility by eslicarbazepine acetate was shown.

Animal Data

In a juvenile animal study in which eslicarbazepine acetate (40, 80, 160 mg/kg/day) was orally administered to young dogs for 10 months starting on postnatal day 21, adverse effects on bone growth (decreased bone mineral content and density) were seen in females at all doses at the end of the dosing period, but not at the end of a 2-month recovery period. Convulsions were seen at the highest dose tested. A no-effect dose for adverse effects in juvenile dogs was not identified. The lowest dose tested is less than the maximum recommended pediatric dose (1200 mg/day) on a body surface area (mg/m2) basis.

A separate juvenile animal study was conducted to assess possible adverse effects on the immune system. Eslicarbazepine acetate (10, 40, 80 mg/kg/day) was orally administered to young dogs for 17 weeks starting on postnatal day 21. No effects on the immune system were observed.

Dizziness and Disturbance in Gait and Coordination

APTIOM causes dose-related increases in adverse reactions related to dizziness and disturbance in gait and coordination (dizziness, ataxia, vertigo, balance disorder, gait disturbance, nystagmus, and abnormal coordination) [see Adverse Reactions ]. In controlled adult adjunctive epilepsy trials, these events were reported in 26% and 38% of patients randomized to receive APTIOM at doses of 800 mg and 1200 mg/day, respectively, compared to 12% of placebo-treated patients. Events related to dizziness and disturbance in gait and coordination were more often serious in APTIOM-treated patients than in placebo-treated patients (2% vs. 0%), and more often led to study withdrawal in APTIOM-treated patients than in placebo-treated patients (9% vs. 0.7%). There was an increased risk of these adverse reactions during the titration period (compared to the maintenance period) and there also may be an increased risk of these adverse reactions in patients 60 years of age and older compared to younger adults. Nausea and vomiting also occurred with these events. Adverse reactions related to dizziness and disturbance in gait and coordination were also observed in adult monotherapy trials and pediatric trials.

The incidence of dizziness was greater with the concomitant use of APTIOM and carbamazepine compared to the use of APTIOM without carbamazepine in adult and pediatric trials. Therefore, consider dosage modifications of both APTIOM and carbamazepine if these drugs are used concomitantly [see Dosage and Administration ].

Somnolence and Fatigue

APTIOM causes dose-dependent increases in somnolence and fatigue-related adverse reactions (fatigue, asthenia, malaise, hypersomnia, sedation, and lethargy). In the controlled adult adjunctive epilepsy trials, these events were reported in 13% of placebo patients, 16% of patients randomized to receive 800 mg/day APTIOM, and 28% of patients randomized to receive 1200 mg/day APTIOM. Somnolence and fatigue-related events were serious in 0.3% of APTIOM-treated patients (and 0 placebo patients) and led to discontinuation in 3% of APTIOM-treated patients (and 0.7% of placebo-treated patients). Somnolence and fatigue-related reactions were also observed in adult monotherapy trials and in pediatric trials.

Cognitive Dysfunction

APTIOM causes dose-dependent increases in cognitive dysfunction-related events in adults (memory impairment, disturbance in attention, amnesia, confusional state, aphasia, speech disorder, slowness of thought, disorientation, and psychomotor retardation). In the controlled adult adjunctive epilepsy trials, these events were reported in 1% of placebo patients, 4% of patients randomized to receive 800 mg/day APTIOM, and 7% of patients randomized to receive 1200 mg/day APTIOM. Cognitive dysfunction-related events were serious in 0.2% of APTIOM-treated patients (and 0.2% of placebo patients) and led to discontinuation in 1% of APTIOM-treated patients (and 0.5% of placebo-treated patients). Cognitive dysfunction events were also observed in adult monotherapy trials.

Visual Changes

APTIOM causes dose-dependent increases in events related to visual changes including diplopia, blurred vision, and impaired vision. In the controlled adult adjunctive epilepsy trials, these events were reported in 16% of patients randomized to receive APTIOM compared to 6% of placebo patients. Eye events were serious in 0.7% of APTIOM-treated patients (and 0 placebo patients) and led to discontinuation in 4% of APTIOM-treated patients (and 0.2% of placebo-treated patients). There was an increased risk of these adverse reactions during the titration period (compared to the maintenance period) and also in patients 60 years of age and older (compared to younger adults). The incidence of diplopia was greater with the concomitant use of APTIOM and carbamazepine compared to the use of APTIOM without carbamazepine (up to 16% vs. 6%, respectively) [see Dosage and Administration ]. Similar adverse reactions related to visual changes were also observed in adult monotherapy trials and in pediatric trials.

Hazardous Activities

Prescribers should advise patients against engaging in hazardous activities requiring mental alertness, such as operating motor vehicles or dangerous machinery, until the effect of APTIOM is known.

Adult Patients

In monotherapy trials in patients with partial-onset seizures [Study 1 and Study 2, see Clinical Studies ], 365 patients received APTIOM, of whom 225 were treated for longer than 12 months and 134 for longer than 24 months. Of the patients in those trials, 95% were between 18 and 65 years old; 48% were male, and 84% were Caucasian. Across controlled and uncontrolled trials in patients receiving adjunctive therapy for partial-onset seizures, 1195 patients received APTIOM, of whom 586 were treated for longer than 6 months and 462 for longer than 12 months. In the placebo controlled adjunctive therapy trials in patients with partial-onset seizures (Study 3, Study 4 and Study 5), 1021 patients received APTIOM. Of the patients in those trials, approximately 95% were between 18 and 60 years old, approximately 50% were male, and approximately 80% were Caucasian.

Monotherapy Historical Control Trials

In the monotherapy epilepsy trials (Study 1 and Study 2), 13% of patients randomized to receive APTIOM at the recommended doses of 1200 mg and 1600 mg once daily discontinued from the trials as a result of an adverse event. The adverse reaction most commonly (≥1% on APTIOM) leading to discontinuation was hyponatremia.

Adverse reactions observed in these studies were generally similar to those observed and attributed to drug in adjunctive placebo-controlled studies. Because these studies did not include a placebo control group, causality could not be established.

Dizziness, nausea, somnolence, and fatigue were all reported at lower incidences during the AED Withdrawal Phase and Monotherapy Phase compared with the Titration Phase.

Adjunctive Therapy Controlled Trials

In the controlled adjunctive therapy epilepsy trials (Study 3, Study 4, and Study 5), the rate of discontinuation as a result of any adverse reaction was 14% for the 800 mg dose, 25% for the 1200 mg dose, and 7% in subjects randomized to placebo. The adverse reactions most commonly (≥1% in any APTIOM treatment group, and greater than placebo) leading to discontinuation, in descending order of frequency, were dizziness, nausea, vomiting, ataxia, diplopia, somnolence, headache, blurred vision, vertigo, asthenia, fatigue, rash, dysarthria, and tremor.

The most frequently reported adverse reactions in patients receiving APTIOM at doses of 800 mg or 1200 mg (≥4% and ≥2% greater than placebo) were dizziness, somnolence, nausea, headache, diplopia, vomiting, fatigue, vertigo, ataxia, blurred vision, and tremor.

Table 4 gives the incidence of adverse reactions that occurred in ≥2% of subjects with partial-onset seizures in any APTIOM treatment group and for which the incidence was greater than placebo during the controlled clinical trials. Adverse reactions during titration were less frequent for patients who began therapy at an initial dose of 400 mg for 1 week and then increased to 800 mg compared to patients who initiated therapy at 800 mg.

Pediatric Patients (4 to 17 Years of Age)

Clinical studies of pediatric patients 4 to 17 years of age were conducted which support the safety and tolerability of APTIOM for the treatment of partial-onset seizures. Across studies in pediatric patients with partial-onset seizures, 393 patients ages 4 to 17 years received APTIOM, of whom 265 received APTIOM for at least 1 year. Adverse reactions reported in clinical studies of pediatric patients 4 to 17 years of age were similar to those seen in adult patients.

Other Adverse Reactions with APTIOM Use

Compared to placebo, APTIOM use was associated with slightly higher frequencies of decreases in hemoglobin and hematocrit, increases in total cholesterol, triglycerides, and LDL, and increases in creatine phosphokinase.

Adverse Reactions Based on Gender and Race

No significant gender differences were noted in the incidence of adverse reactions. Although there were few non-Caucasian patients, no differences in the incidences of adverse reactions compared to Caucasian patients were observed.

Absorption, Distribution, Metabolism, and Excretion

Absorption

APTIOM is mostly undetectable (0.01% of the systemic exposure) after oral administration. Eslicarbazepine, the major metabolite, is primarily responsible for the pharmacological effect of APTIOM. Peak plasma concentrations (Cmax) of eslicarbazepine are attained at 1-4 hours post-dose. Eslicarbazepine is highly bioavailable, because the amount of eslicarbazepine and glucuronide metabolites recovered in urine corresponded to more than 90% of an APTIOM dose. Food has no effect on the pharmacokinetics of eslicarbazepine after oral administration of APTIOM.

Distribution

The binding of eslicarbazepine to plasma proteins is relatively low (<40%) and independent of concentration. In vitro studies have shown that plasma protein binding was not relevantly affected by the presence of warfarin, diazepam, digoxin, phenytoin, or tolbutamide. Similarly, the binding of warfarin, diazepam, digoxin, phenytoin or tolbutamide was not significantly affected by the presence of eslicarbazepine. The apparent volume of distribution of eslicarbazepine is 61 L for body weight of 70 kg based on population PK analysis.

Metabolism

APTIOM is rapidly and extensively metabolized to its major active metabolite eslicarbazepine by hydrolytic first-pass metabolism. Eslicarbazepine corresponds to 91% of systemic exposure. The systemic exposure to minor active metabolites of (R)-licarbazepine is 5% and oxcarbazepine is 1%. The inactive glucuronides of these active metabolites correspond to approximately 3% of systemic exposure.

In in vitro studies in human liver microsomes, eslicarbazepine had no clinically relevant inhibitory effect on the activity of CYP1A2, CYP2A6, CYP2B6, CYP2D6, CYP2E1, and CYP3A4, and only a moderate inhibitory effect on CYP2C19. Studies with eslicarbazepine in fresh human hepatocytes showed no induction of enzymes involved in glucuronidation and sulfation of 7-hydroxy-coumarin. A mild activation of UGT1A1-mediated glucuronidation was observed in human hepatic microsomes.

No apparent autoinduction of metabolism has been observed with APTIOM in humans.

Excretion

APTIOM metabolites are eliminated from the systemic circulation primarily by renal excretion, in the unchanged and glucuronide conjugate forms. In total, eslicarbazepine and its glucuronide account for more than 90% of total metabolites excreted in urine, approximately two thirds in the unchanged form and one third as glucuronide conjugate. Other minor metabolites account for the remaining 10% excreted in the urine. In healthy subjects with normal renal function, the renal clearance of eslicarbazepine (approximately 20 mL/min) is substantially lower than glomerular filtration rate (80-120 mL/min), suggesting that renal tubular reabsorption occurs. The apparent plasma half-life of eslicarbazepine was 13-20 hours in epilepsy patients [see Dosage and Administration and Use in Specific Populations ].

Specific Populations

Geriatric Patients (≥65 Years of Age)

The pharmacokinetic profile of eslicarbazepine was unaffected in elderly subjects with creatinine clearance >60 mL/min compared to healthy subjects (18-40 years) after single and repeated doses of 600 mg APTIOM during 8 days of dosing. No dose adjustment is necessary in adults based on age, if CrCl is ≥50 mL/min.

Pediatric Patients (4 to 17 Years of Age)

A pharmacokinetic study of APTIOM was performed in 29 pediatric patients with partial-onset seizures. Limited pharmacokinetic sampling was also performed during controlled pediatric adjunctive therapy partial-onset seizure studies. As in adult patients, APTIOM is rapidly and extensively metabolized to its major active metabolite eslicarbazepine.  The pharmacokinetics of eslicarbazepine is linear and dose-proportional in the dose range of 5 to 30 mg/kg/day. Peak plasma concentrations (Cmax) of eslicarbazepine are attained at 1-3 hours post-dose.

A population pharmacokinetic analysis showed that body weight significantly correlates with the clearance of eslicarbazepine in pediatric patients; clearance increased with an increase in body weight. A weight-based dosing regimen is necessary to achieve eslicarbazepine exposures in pediatric patients aged 4 to 17 years similar to those observed in adults treated at effectives doses of APTIOM [see Dosage and Administration ]. The apparent half-life of eslicarbazepine in plasma was 10-16 hours in pediatric patients with partial-onset seizures. Steady-state plasma concentrations are attained after 4 to 5 days of once- daily dosing.

The pharmacokinetics of eslicarbazepine in pediatric patients are similar when used as monotherapy or as adjunctive therapy for the treatment of partial-onset seizures.

Gender

Studies in healthy subjects and patients showed that pharmacokinetics of eslicarbazepine was not affected by gender.

Race

No clinically significant effect of race (Caucasian N=849, Black N=53, Asian N=65, and Other N=51) on the pharmacokinetics of eslicarbazepine was noted in a population pharmacokinetic analysis of pooled data from the clinical studies.

Renal Impairment

APTIOM metabolites are eliminated from the systemic circulation primarily by renal excretion. The extent of systemic exposure of eslicarbazepine following an 800 mg single dose was increased by 62% in patients with mild renal impairment (CrCl 50-80 mL/min), by 2-fold in patients with moderate renal impairment (CrCl 30-49 mL/min) and by 2.5-fold in patients with severe renal impairment (CrCl <30 mL/min) in comparison to the healthy subjects (CrCl >80 mL/min). Dosage adjustment is recommended in patients with creatinine clearance below 50 mL/min [see Dosage and Administration and Use in Specific Populations ].

In patients with end stage renal disease, repeated hemodialysis removed APTIOM metabolites from systemic circulation.

Hepatic Impairment

The pharmacokinetics and metabolism of APTIOM was evaluated in healthy subjects and patients with moderate liver impairment (7-9 points on the Child-Pugh assessment) after multiple oral doses (see Figure 1). Moderate hepatic impairment did not affect the pharmacokinetics of APTIOM. No dose adjustment is recommended in patients with mild to moderate liver impairment.

The pharmacokinetics of APTIOM has not been studied in patients with severe hepatic impairment.

Figure 1: Impact of Intrinsic Factors on AUC of Eslicarbazepine

Drug Interaction Studies

Potential for Other AEDs to Affect Eslicarbazepine

The potential impact of other AEDs on the systemic exposure (area under the curve, AUC) of eslicarbazepine, the active metabolite of APTIOM, is shown in Figure 2:

Figure 2: Potential Impact of Other AEDs on AUC of Eslicarbazepine

Potential for APTIOM to Affect Other Drugs

The potential impact of APTIOM on the systemic exposure (AUC) of other drugs (including AEDs) is shown in Figures 3a and 3b:

Figure 3a: Potential Impact of APTIOM on the AUC of AEDs

Figure 3b: Potential Impact of APTIOM on the AUC of Non-AEDs

Carcinogenesis

In a two-year carcinogenicity study in mice, eslicarbazepine acetate was administered orally at doses of 100, 250, and 600 mg/kg/day. An increase in the incidence of hepatocellular adenomas and carcinomas was observed at 250 and 600 mg/kg/day in males and at 600 mg/kg/day in females. The dose not associated with an increase in tumors (100 mg/kg/day) is less than the MRHD (1600 mg/day for monotherapy) on a mg/m2 basis.

Mutagenesis

Eslicarbazepine acetate and eslicarbazepine were not mutagenic in the in vitro Ames assay. In in vitro assays in mammalian cells, eslicarbazepine acetate and eslicarbazepine were not clastogenic in human peripheral blood lymphocytes; however, eslicarbazepine acetate was clastogenic in Chinese hamster ovary (CHO) cells, with and without metabolic activation. Eslicarbazepine acetate was positive in the in vitro mouse lymphoma tk assay in the absence of metabolic activation. Eslicarbazepine acetate was not clastogenic in the in vivo mouse micronucleus assay.

Impairment of Fertility

When eslicarbazepine acetate (150, 350, and 650 mg/kg/day) was orally administered to male and female mice prior to and throughout the mating period, and continuing in females to gestation day 6, there was an increase in embryolethality at all doses. The lowest dose tested is less than the MRHD on a mg/m2 basis.

When eslicarbazepine acetate (65, 125, 250 mg/kg/day) was orally administered to male and female rats prior to and throughout the mating period, and continuing in females to implantation, lengthening of the estrus cycle was observed at the highest dose tested. The data in rats are of uncertain relevance to humans because of differences in metabolic profile between species.