Vimpat Drug Information

Partial-Onset Seizures VIMPAT is indicated for the treatment of partial-onset seizures in patients 1 month of age and older.

Primary Generalized Tonic-Clonic Seizures VIMPAT is indicated as adjunctive therapy in the treatment of primary generalized tonic-clonic seizures in patients 4 years of age and older.

Dosage Information

The recommended dosage for monotherapy and adjunctive therapy for partial-onset seizures in patients 1 month of age and older and for adjunctive therapy for primary generalized tonic-clonic seizures in patients 4 years of age and older is included in Table 1. In pediatric patients, the recommended dosing regimen is dependent upon body weight. 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. Oral and intravenous dosages are the same unless specified. In adjunctive clinical trials in adult patients with partial-onset seizures, a dosage higher than 200 mg twice daily (400 mg per day) was not more effective and was associated with a substantially higher rate of adverse reactions.

VIMPAT Injection Dosage VIMPAT injection may be used when oral administration is temporarily not feasible. VIMPAT injection can be administered intravenously to adult and pediatric patients weighing 6 kg or more with the same dosing regimens described for oral dosing. For pediatric patients weighing less than 6 kg, VIMPAT injection may be initiated with a dose of 0.66 mg/kg three times daily (see Table 1 ).

The clinical study experience of intravenous VIMPAT is limited to 5 days of consecutive treatment.

The alternate initial dosage regimen should be continued for one week. VIMPAT may then be titrated based on clinical response and tolerability, no more frequently than once per week, if needed. The loading dose should be administered with medical supervision because of the possibility of increased incidence of adverse reactions, including central nervous system (CNS) and cardiovascular adverse reactions.

Table 2: Alternate Initial Dosing Regimen to Achieve the Maintenance Dosage in a Shorter Timeframe if Clinically Indicated when not specified, the dosage is the same for monotherapy for partial-onset seizures and adjunctive therapy for partial-onset seizures or primary generalized tonic-clonic seizures.

Converting From a Single Antiepileptic (AED) to VIMPAT Monotherapy for the Treatment of Partial-Onset Seizures For patients who are already on a single AED and will convert to VIMPAT monotherapy, withdrawal of the concomitant AED should not occur until the therapeutic dosage of VIMPAT is achieved and has been administered for at least 3 days. A gradual withdrawal of the concomitant AED over at least 6 weeks is recommended.

Dosage Information for Patients with Renal Impairment

For patients with mild to moderate renal impairment, no dosage adjustment is necessary. For patients with severe renal impairment or end-stage renal disease, a reduction of 25% of the maximum dosage is recommended. In all patients with renal impairment, dose initiation and titration should be based on clinical response and tolerability.

Hemodialysis VIMPAT is effectively removed from plasma by hemodialysis. Following a 4-hour hemodialysis treatment, dosage supplementation of up to 50% should be considered. Concomitant Strong CYP3A4 or CYP2C9 Inhibitors Dose reduction may be necessary in patients with renal impairment who are taking strong inhibitors of CYP3A4 and CYP2C9.

Administration Instructions for VIMPAT Tablets and Oral Solution VIMPAT tablets and oral solution may be taken with or without food. VIMPAT Tablets VIMPAT tablets should be swallowed whole with liquid. Do not divide VIMPAT tablets.

VIMPAT Oral Solution A calibrated measuring device is recommended to measure and deliver the prescribed dose accurately. A household teaspoon or tablespoon is not an adequate measuring device. VIMPAT oral solution may also be administered using a nasogastric tube or gastrostomy tube.

Discard any unused VIMPAT oral solution remaining after 6 months of first opening the bottle.

Preparation and Administration Information for VIMPAT Injection Preparation VIMPAT injection can be administered intravenously without further dilution or may be mixed with diluents listed below. The diluted solution should not be stored for more than 4 hours at room temperature. Diluents: Sodium Chloride Injection 0.9% (w/v) Dextrose Injection 5% (w/v) Lactated Ringer's Injection Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

Product with particulate matter or discoloration should not be used. VIMPAT injection is for single-dose only. Any unused portion of VIMPAT injection should be discarded.

Administration The recommended infusion duration is 30 to 60 minutes; however, infusions as rapid as 15 minutes can be administered in adults if required. Infusion durations less than 30 minutes are generally not recommended in pediatric patients. Intravenous infusion of VIMPAT may cause bradycardia, AV blocks, and ventricular tachyarrhythmia.

Obtaining an ECG before beginning VIMPAT and after VIMPAT is titrated to steady-state maintenance dose is recommended in patients with underlying proarrhythmic conditions or on concomitant medications that affect cardiac conduction.

Discontinuation of VIMPAT

When discontinuing VIMPAT, a gradual withdrawal over at least 1 week is recommended.

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. VIMPAT Tablet and Oral Solution in Adults In the premarketing development of adjunctive therapy for partial-onset seizures, 1327 adult patients received VIMPAT tablets in controlled and uncontrolled trials, of whom 1000 were treated for longer than 6 months, and 852 for longer than 12 months. Partial-Onset Seizures Monotherapy Historical-Control Trial (Study 1) In the monotherapy trial for partial-onset seizures, 16% of patients randomized to receive VIMPAT at the recommended doses of 300 and 400 mg/day discontinued from the trial as a result of an adverse reaction.

The adverse reaction most commonly (≥1% on VIMPAT) leading to discontinuation was dizziness. Adverse reactions that occurred in this study were generally similar to those that occurred in adjunctive placebo-controlled studies. One adverse reaction, insomnia, occurred at a rate of ≥2% and was not reported at a similar rate in previous studies.

This adverse reaction has also been observed in postmarketing experience. Because this study did not include a placebo control group, causality could not be established. Dizziness, headache, nausea, somnolence, and fatigue all occurred at lower incidences during the AED Withdrawal Phase and Monotherapy Phase, compared with the Titration Phase.

The adverse reactions most commonly (>1% on VIMPAT and greater than placebo) leading to discontinuation were dizziness, ataxia, vomiting, diplopia, nausea, vertigo, and blurred vision. Table 4 gives the incidence of adverse reactions that occurred in ≥2% of adult patients with partial-onset seizures in the VIMPAT total group and for which the incidence was greater than placebo. Table 4: Adverse Reactions Incidence in Adjunctive Therapy Pooled, Placebo-Controlled Trials in Adult Patients with Partial-Onset Seizures Studies The overall adverse reaction rate was similar in male and female patients.

Although there were few non-Caucasian patients, no differences in the incidences of adverse reactions compared to Caucasian patients were observed. VIMPAT Tablet and Oral Solution in Pediatric Patients Safety of VIMPAT was evaluated in clinical studies of pediatric patients 1 month to less than 17 years of age for the treatment of partial-onset seizures. Adverse reactions reported in clinical studies of pediatric patients 1 month to less than 17 years of age were similar to those seen in adult patients.

Additionally, an adverse reaction not previously reported of myoclonic epilepsy was reported in 3% of patients treated with VIMPAT compared to 1% of patients who received placebo. It is also noted that 2 patients receiving VIMPAT had acute worsening of seizures shortly after drug initiation, including one episode of status epilepticus, compared to no patients receiving placebo. Laboratory Abnormalities Abnormalities in liver function tests have occurred in controlled trials with VIMPAT in adult patients with partial-onset seizures who were taking 1 to 3 concomitant anti-epileptic drugs.

One case of hepatitis with transaminases >20× ULN occurred in one healthy subject 10 days after VIMPAT treatment completion, along with nephritis (proteinuria and urine casts). Serologic studies were negative for viral hepatitis. Transaminases returned to normal within one month without specific treatment.

At the time of this event, bilirubin was normal. The hepatitis/nephritis was interpreted as a delayed hypersensitivity reaction to VIMPAT. Other Adverse Reactions The following is a list of adverse reactions reported by patients treated with VIMPAT in all clinical trials in adult patients, including controlled trials and long-term open-label extension trials.

Adverse reactions addressed in other tables or sections are not listed here. Blood and lymphatic system disorders: neutropenia, anemia Cardiac disorders: palpitations Ear and labyrinth disorders: tinnitus Gastrointestinal disorders: constipation, dyspepsia, dry mouth, oral hypoaesthesia General disorders and administration site conditions: irritability, pyrexia, feeling drunk Injury, poisoning, and procedural complications: fall Musculoskeletal and connective tissue disorders: muscle spasms Nervous system disorders: paresthesia, cognitive disorder, hypoaesthesia, dysarthria, disturbance in attention, cerebellar syndrome Psychiatric disorders: confusional state, mood altered, depressed mood VIMPAT Injection Adult Patients (17 Years and Older) Adverse reactions with intravenous administration to adult patients with partial-onset seizures generally were similar to those that occurred with the oral formulation, although intravenous administration was associated with local adverse reactions such as injection site pain or discomfort (2.5%), irritation (1%), and erythema (0.5%). One case of profound bradycardia (26 bpm: BP 100/60 mmHg) occurred in a patient during a 15-minute infusion of 150 mg VIMPAT.

This patient was on a beta-blocker. Infusion was discontinued and the patient experienced a rapid recovery. The safety of a 15-minute loading dose administration of VIMPAT Injection 200 mg to 400 mg followed by oral administration of VIMPAT given twice daily at the same total daily dose as the initial intravenous infusion was assessed in an open-label study in adult patients with partial-onset seizures.

Patients had to have been maintained on a stable dose regimen of 1 to 2 marketed antiepileptics for at least 28 days prior to treatment assignment. Table 5 gives the incidence of adverse reactions that occurred in ≥5% of adult patients in any VIMPAT dosing group. Table 5: Adverse Reactions in a 15-minute Infusion Study in Adult Patients with Partial-Onset Seizures Adverse reactions that occurred with infusion of VIMPAT 200 mg over 15-minutes followed by VIMPAT 100 mg administered orally twice per day were similar in frequency to those that occurred in 3-month adjunctive therapy controlled trials.

Considering the difference in period of observations (1 week vs. 3 months), the incidence of CNS adverse reactions, such as dizziness, somnolence, and paresthesia may be higher with 15-minute administration of VIMPAT Injection than with administration over a 30-to 60-minute period. The adverse reactions associated with VIMPAT injection in adult patients with primary generalized tonic-clonic seizures are expected to be similar to those seen in adults with partial-onset seizures. Infusions were primarily administered over a 30 to 60 minute time period; infusion times less than 30 minutes were not adequately studied in pediatric patients.

Although no serious or severe adverse reactions were noted at the time of infusion in this small study, the adverse reactions associated with VIMPAT injection in pediatric patients are expected to be similar to those noted in adults. In a retrospective cohort study of electronic healthcare records of 686 pediatric patients who started VIMPAT with intravenous dosing, the incidence of rash within 30 days of discontinuation of intravenous VIMPAT was two-fold higher in the cohort of patients who were initiated with the alternate initial dosing regimen to achieve the maintenance dosage in a shorter timeframe compared to the cohort of patients who were initiated with a lower initial dosage regimen.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of VIMPAT. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Blood and lymphatic system disorders: Agranulocytosis Psychiatric disorders: Aggression, agitation, hallucination, insomnia, psychotic disorder Skin and subcutaneous tissue disorders: Angioedema, rash, urticaria, Stevens-Johnson syndrome, toxic epidermal necrolysis.

Neurologic disorders: Dyskinesia, new or worsening seizures

Strong CYP3A4 or CYP2C9 Inhibitors Patients with renal or hepatic impairment who are taking strong inhibitors of CYP3A4 and CYP2C9 may have a significant increase in exposure to VIMPAT. Dose reduction may be necessary in these patients.

Concomitant Medications that Affect Cardiac Conduction VIMPAT should be used with caution in patients on concomitant medications that affect cardiac conduction (sodium channel blockers, beta-blockers, calcium channel blockers, potassium channel blockers) including those that prolong PR interval (including sodium channel blocking AEDs), because of a risk of AV block, bradycardia, or ventricular tachyarrhythmia. In such patients, obtaining an ECG before beginning VIMPAT, and after VIMPAT is titrated to steady-state, is recommended. In addition, these patients should be closely monitored if they are administered VIMPAT through the intravenous route.

Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to antiepileptic drugs (AEDs), such as VIMPAT, during pregnancy. Encourage women who are taking VIMPAT 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 Available data from the North American Antiepileptic Drug (NAAED) pregnancy registry, a prospective cohort study, case reports, and a case series with VIMPAT use in pregnant women are insufficient to identify a drug-associated risk of major birth defects, miscarriage or other adverse maternal or fetal outcomes.

Lacosamide produced developmental toxicity (increased embryofetal and perinatal mortality, growth deficit) in rats following administration during pregnancy. Developmental neurotoxicity was observed in rats following administration during a period of postnatal development corresponding to the third trimester of human pregnancy. These effects were observed at doses associated with clinically relevant plasma exposures (see Data ).

The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. 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.

However, the maximum doses evaluated were limited by maternal toxicity in both species and embryofetal death in rats. These doses were associated with maternal plasma lacosamide exposures (AUC) approximately 2 and 1 times (rat and rabbit, respectively) that in humans at the maximum recommended human dose (MRHD) of 400 mg/day. The no-effect dose for pre- and postnatal developmental toxicity in rats (70 mg/kg/day) was associated with a maternal plasma lacosamide AUC similar to that in humans at the MRHD.

Oral administration of lacosamide (30, 90, or 180 mg/kg/day) to rats during the neonatal and juvenile periods of development resulted in decreased brain weights and long-term neurobehavioral changes (altered open field performance, deficits in learning and memory). The early postnatal period in rats is generally thought to correspond to late pregnancy in humans in terms of brain development. The no-effect dose for developmental neurotoxicity in rats was associated with a plasma lacosamide AUC less than that in humans at the MRHD.

In Vitro Data Lacosamide has been shown in vitro to interfere with the activity of collapsin response mediator protein-2 (CRMP-2), a protein involved in neuronal differentiation and control of axonal outgrowth. Potential adverse effects on CNS development related to this activity cannot be ruled out.

Pediatric Use Partial-Onset Seizures Safety and effectiveness of VIMPAT for the treatment of partial-onset seizures have been established in pediatric patients 1 month to less than 17 years of age. Use of VIMPAT in this age group is supported by evidence from adequate and well-controlled studies of VIMPAT in adults with partial-onset seizures, pharmacokinetic data from adult and pediatric patients, and safety data in 847 pediatric patients 1 month to less than 17 years of age. Safety and effectiveness in pediatric patients below 1 month of age have not been established.

Primary Generalized Tonic-Clonic Seizures Safety and effectiveness of VIMPAT as adjunctive therapy in the treatment of primary generalized tonic-clonic seizures in pediatric patients with idiopathic generalized epilepsy 4 years of age and older was established in a 24-week double-blind, randomized, placebo-controlled, parallel-group, multi-center study (Study 5), which included 37 pediatric patients 4 years to less than 17 years of age. Safety and effectiveness in pediatric patients below the age of 4 years have not been established. Animal Data Lacosamide has been shown in vitro to interfere with the activity of collapsin response mediator protein-2 (CRMP-2), a protein involved in neuronal differentiation and control of axonal outgrowth.

Potential related adverse effects on CNS development cannot be ruled out. Administration of lacosamide to rats during the neonatal and juvenile periods of postnatal development (approximately equivalent to neonatal through adolescent development in humans) resulted in decreased brain weights and long-term neurobehavioral changes (altered open field performance, deficits in learning and memory). The no-effect dose for developmental neurotoxicity in rats was associated with a plasma lacosamide exposure (AUC) less than that in humans at the maximum recommended human dose of 400 mg/day.

Events reported after an intake of more than 800 mg (twice the maximum recommended daily dosage) of VIMPAT include dizziness, nausea, and seizures (generalized tonic-clonic seizures, status epilepticus). Cardiac conduction disorders, confusion, decreased level of consciousness, cardiogenic shock, cardiac arrest, and coma have also been observed. Fatalities have occurred following lacosamide overdoses of several grams.

There is no specific antidote for overdose with VIMPAT. Standard decontamination procedures should be followed. General supportive care of the patient is indicated including monitoring of vital signs and observation of the clinical status of patient.

A Certified Poison Control Center should be contacted for up to date information on the management of overdose with VIMPAT. Standard hemodialysis procedures result in significant clearance of VIMPAT (reduction of systemic exposure by 50% in 4 hours). Hemodialysis may be indicated based on the patient's clinical state or in patients with significant renal impairment.