VIGAFYDE

1 INDICATIONS AND USAGE VIGAFYDE is indicated as monotherapy for the treatment of i nfantile spasms in pediatric patients 1 month to 2 years of age for whom the potential benefits outweigh the potential risk of vision loss ( 1 ) VIGAFYDE is indicated as monotherapy for the treatment of infantile spasms in pediatric patients 1 month to 2 years of age for whom the potential benefits outweigh the potential risk of vision loss [see Warnings and Precautions ( 5.1 )].

6 ADVERSE REACTIONS The following serious and otherwise important adverse reactions are described elsewhere in labeling: Permanent Vision Loss [see BOXED WARNING and Warnings and Precautions ( 5.1 )] Magnetic Resonance Imaging (MRI) Abnormalities in Infants [see Warnings and Precautions ( 5.3 )] Neurotoxicity [see Warnings and Precautions ( 5.4 )] Withdrawal of Antiepileptic Drugs (AEDs) [see Warnings and Precautions ( 5.5 )] Anemia [see Warnings and Precautions ( 5.6 )] Somnolence and Fatigue [see Warnings and Precautions ( 5.7 )] Peripheral Neuropathy [see Warnings and Precautions ( 5.8 )] Weight Gain [see Warnings and Precautions ( 5.9 )] Edema [see Warnings and Precautions ( 5.10 )] Suicidal Behavior and Ideation with Unapproved use in Adolescents and Adults [see Warnings and Precautions ( 5.11 )] The most common adverse reactions (incidence ˃5% and greater than on placebo) in patients with infantile spasms include somnolence, bronchitis, ear infection, and acute otitis media ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Pyros Pharmaceuticals, Inc. at 1-855-406-1010 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 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. Infantile Spasms In a randomized, placebo-controlled study in patients with infantile spasms (IS) with a 5 day double-blind treatment phase (n=40), the adverse reactions that occurred in ≥5% of patients receiving vigabatrin and that occurred more frequently than in placebo patients were somnolence (vigabatrin 45%, placebo 30%), bronchitis (vigabatrin 30%, placebo 15%), ear infection (vigabatrin 10%, placebo 5%), and acute otitis media (vigabatrin 10%, placebo 0%). In patients with IS, the adverse reactions most commonly associated with vigabatrin treatment discontinuation in ≥1% of patients were infections, status epilepticus, developmental coordination disorder, dystonia, hypotonia, hypertonia, weight gain, and insomnia. In a dose response study of low-dose (18-36 mg/kg/day), which is below the recommended starting dose for IS of 50 mg/kg/day), versus high-dose (100-148 mg/kg/day) vigabatrin, no clear correlation between dose and incidence of adverse reactions was observed. The adverse reactions (≥5% in either dose group) are summarized in Table 2. Table 2. Adverse Reactions in a Placebo-Controlled Trial in Patients with Infantile Spasms Body System Adverse Reaction Vigabatrin Low Dose [N=114] % Vigabatrin High Dose [N=108] % Eye Disorders (other than field or acuity changes) Strabismus 5 5 Conjunctivitis 5 2 Gastrointestinal Disorders Vomiting 14 20 Constipation 14 12 Diarrhea 13 12 General Disorders Fever 29 19 Infections Upper respiratory tract infection 51 46 Otitis media 44 30 Viral infection 20 19 Pneumonia 13 11 Candidiasis 8 3 Ear infection 7 14 Gastroenteritis viral 6 5 Sinusitis 5 9 Urinary tract infection 5 6 Influenza 5 3 Croup infectious 5 1 Metabolism and Nutrition Disorders Decreased appetite 9 7 Nervous System Disorders Sedation 19 17 Somnolence 17 19 Status epilepticus 6 4 Lethargy 5 7 Convulsion 4 7 Hypotonia 4 6 Psychiatric Disorders Irritability 16 23 Insomnia 10 12 Re s piratory Disorders Nasal congestion 13 4 Cough 3 8 Skin and Subcutaneous Tissue Disorders Rash 8 11 6.2 Postm arketing Experience The following adverse reactions have been identified during postapproval use of vigabatrin. 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. Ear Disorders : Deafness Endocrine Disorders : Delayed puberty Gastrointestinal Disorders : Gastrointestinal hemorrhage, esophagitis General Disorders : Developmental delay, facial edema, malignant hyperthermia, multi-organ failure Hepatobiliary Disorders : Cholestasis Nervous System Disorders : Dystonia, encephalopathy, hypertonia, hypotonia, muscle spasticity, myoclonus, optic neuritis, dyskinesia Psychiatric Disorders : Acute psychosis, apathy, delirium, hypomania, neonatal agitation, psychotic disorder Respiratory Disorders : Laryngeal edema, pulmonary embolism, respiratory failure, stridor Skin and Subcutaneous Tissue Disorders : Angioedema, maculo-papular rash, pruritus, Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), alopecia

4 CONTRAINDICATIONS None. None ( 4 )

11 DESCRIPTION VIGAFYDE (vigabatrin oral solution) is an antiepileptic drug. The chemical name of vigabatrin, is (±) 4-amino-5-hexenoic acid, a racemic mixture of R and S isomers. The molecular formula is C 6 H 11 NO 2 and the molecular weight is 129.16. It has the following structural formula: Vigabatrin is a white to off-white powder which is freely soluble in water, slightly soluble in methyl alcohol, very slightly soluble in ethyl alcohol and chloroform, and insoluble in toluene and hexane. The pH of a 1% aqueous solution is about 6.9. The n-octanol/water partition coefficient of vigabatrin is about 0.011 (log P=-1.96) at physiologic pH. Vigabatrin melts with decomposition in a 3-degree range within the temperature interval of 171ºC to 176ºC. The dissociation constants (pKa) of vigabatrin are 4 and 9.7 at room temperature (25ºC). Each mL of VIGAFYDE contains 100 mg of vigabatrin. The inactive ingredients are methylparaben; peppermint flavor; propylparaben; purified water; and sucralose. structural formula for vigabatrin

2 DOSAGE AND ADMINISTRATION VIGAFYDE is a concentrated formulation as compared to other vigabatrin products. Verify the strength and the dose of the product prior to prescribing, dispensing, and administering ( 2.1 ) Initiate at a daily dosage of 50 mg/kg (25 mg/kg twice daily); increase total daily dosage every 3 days, in increments of 25 mg/kg/day to 50 mg/kg/day, up to a maximum daily dosage of 150 mg/kg (75 mg/kg twice daily) ( 2.2 ) 2.1 Important Dosing and Administration Instructions Dosing VIGAFYDE is a solution of 100 mg/mL of vigabatrin intended for oral use only. VIGAFYDE is a concentrated solution as compared to other vigabatrin products. Verify strength and the dose of the product prior to prescribing, dispensing, and administering [see Dosage and Administration ( 2.3 )]. VIGAFYDE does not require additional reconstitution or dilution prior to administration. Use the lowest dosage and shortest exposure to VIGAFYDE consistent with clinical objectives [see Warnings and Precautions ( 5.1 )]. The VIGAFYDE dosing regimen depends on weight. Monitoring of VIGAFYDE plasma concentrations to optimize therapy is not helpful. Administration VIGAFYDE is given orally with or without food. 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. If a decision is made to discontinue VIGAFYDE, the dose should be gradually reduced [see Dosage and Administration ( 2.2 ) and Warnings and Precautions ( 5.5 )]. 2.2 Recommended Dosage for Infantile Spasms The initial daily dosing is 50 mg/kg/day given in two divided doses (25 mg/kg twice daily); subsequent dosing can be titrated by 25 mg/kg/day to 50 mg/kg/day increments every 3 days, up to a maximum of 150 mg/kg/day given in 2 divided doses (75 mg/kg twice daily) [see Use in Specific Populations ( 8.4 )] . Table 1 provides the volume of the 50 mg/mL dosing solution that should be administered as individual doses in infants of various weights. Table 1. Dosing of VIGAFYDE for Infantile Spasms Weight [kg] Starting Dose 50 mg/kg/day Maximum Dose 150 mg/kg/day 3 75 mg (0.75 mL) twice daily 225 mg (2.25 mL) twice daily 4 100 mg (1 mL) twice daily 300 mg (3 mL) twice daily 5 125 mg (1.25 mL) twice daily 375 mg (3.75 mL) twice daily 6 150 mg (1.5 mL) twice daily 450 mg (4.5 mL) twice daily 7 175 mg (1.75 mL) twice daily 525 mg (5.25 mL) twice daily 8 200 mg (2 mL) twice daily 600 mg (6 mL) twice daily 9 225 mg (2.25 mL) twice daily 675 mg (6.75 mL) twice daily 10 250 mg (2.5 mL) twice daily 750 mg (7.5 mL) twice daily 11 275 mg (2.75 mL) twice daily 825 (8.25 mL) twice daily 12 300 mg (3 mL) twice daily 900 (9 mL) twice daily 13 325 mg (3.25 mL) twice daily 975 mg (9.75 mL) twice daily 14 350 mg (3.5 mL) twice daily 1050 mg (10.5 mL) twice daily 15 375 mg (3.75 mL) twice daily 1125 mg (11.25 mL) twice daily 16 400 mg (4 mL) twice daily 1200 mg (12 mL) twice daily In patients with infantile spasms, VIGAFYDE should be withdrawn if a substantial clinical benefit is not observed within 2 to 4 weeks. If, in the clinical judgment of the prescriber, evidence of treatment failure becomes obvious earlier than 2 to 4 weeks, treatment should be discontinued at that time [see Warnings and Precautions ( 5.1 )]. 2.3 Switching Between Other Vigabatrin Products and VIGAFYDE If switching between other vigabatrin products and VIGAFYDE, ensure the correct volume for the correct dosage is prescribed, dispensed, and administered. As compared to other vigabatrin products, VIGAFYDE is a concentrated solution that requires a smaller volume than other vigabatrin products to obtain the same dosage (i.e., VIGAFYDE is 100 mg/mL and currently available vigabatrin for oral solution products have a final concentration of 50 mg/mL). 2.4 Discontinuation of VIGAFYDE Avoid abrupt withdrawal [see Warnings and Precautions ( 5.5 )]. In a controlled clinical study in patients with infantile spasms, vigabatrin was tapered by decreasing the daily dosage at a rate of 25-50 mg/kg every 3-4 days.

10 OVERDOSAGE 10.1 Signs, Symptoms, and Laboratory Findings of Overdosage Confirmed and/or suspected vigabatrin overdoses have been reported during clinical trials and in post marketing surveillance. No vigabatrin overdoses resulted in death. When reported, the vigabatrin dose ingested ranged from 3 g to 90 g, but most were between 7.5 g and 30 g. Nearly half the cases involved multiple drug ingestions including carbamazepine, barbiturates, benzodiazepines, lamotrigine, valproic acid, acetaminophen, and/or chlorpheniramine. Coma, unconsciousness, and/or drowsiness were described in the majority of cases of vigabatrin overdose. Other less commonly reported symptoms included vertigo, psychosis, apnea or respiratory depression, bradycardia, agitation, irritability, confusion, headache, hypotension, abnormal behavior, increased seizure activity, status epilepticus, and speech disorder. These symptoms resolved with supportive care. 10.2 Management of Overdosage There is no specific antidote for VIGAFYDE overdose. Standard measures to remove unabsorbed drug should be used, including elimination by emesis or gastric lavage. Supportive measures should be employed, including monitoring of vital signs and observation of the clinical status of the patient. In an in vitro study, activated charcoal did not significantly adsorb vigabatrin. The effectiveness of hemodialysis in the treatment of VIGAFYDE overdose is unknown. In isolated case reports in renal failure patients receiving therapeutic doses of vigabatrin, hemodialysis reduced vigabatrin plasma concentrations by 40% to 60%.

7 DRUG INTERACTIONS Decreased phenytoin plasma levels: Dosage adjustment may be needed ( 7.1 ). 7.1 Antiepileptic Drugs Phenytoin Although phenytoin dose adjustments are not routinely required, dose adjustment of phenytoin should be considered if clinically indicated, since VIGAFYDE may cause a moderate reduction in total phenytoin plasma levels [see Clinical Pharmacology ( 12.3 )]. Clonazepam VIGAFYDE may moderately increase the C max of clonazepam resulting in an increase of clonazepam-associated adverse reactions [see Clinical Pharmacology ( 12.3 )]. 7.2 Drug-Laboratory Test Interactions VIGAFYDE decreases alanine transaminase (ALT) and aspartate transaminase (AST) plasma activity in up to 90% of patients. In some patients, these enzymes become undetectable. The suppression of ALT and AST activity by vigabatrin may preclude the use of these markers, especially ALT, to detect early hepatic injury. VIGAFYDE may increase the amount of amino acids in the urine, possibly leading to a false positive test for certain rare genetic metabolic diseases (e.g., alpha aminoadipic aciduria).

12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action The precise mechanism of vigabatrin’s anti-seizure effect is unknown, but it is believed to be the result of its action as an irreversible inhibitor of γ-aminobutyric acid transaminase (GABA-T), the enzyme responsible for the metabolism of the inhibitory neurotransmitter GABA. This action results in increased levels of GABA in the central nervous system. No direct correlation between plasma concentration and efficacy has been established. The duration of drug effect is presumed to be dependent on the rate of enzyme re-synthesis rather than on the rate of elimination of the drug from the systemic circulation. 12.2 Pharmacodynamics Effects on Electrocardiogram There is no indication of a QT/QTc prolonging effect of vigabatrin in single doses up to 6.0 g. In a randomized, placebo-controlled, crossover study, 58 healthy subjects were administered a single oral dose of vigabatrin (3 g and 6 g) and placebo. Peak concentrations for 6.0 g vigabatrin were approximately 2-fold higher than the peak concentrations following the 3.0 g single oral dose. 12.3 Pharmacokinetics VIGAFYDE is indicated for treatment in patients 1 month to 2 years of age [see Indications and Usage ( 1 )]. VIGAFYDE is not approved for use in adults. Vigabatrin displayed linear pharmacokinetics after administration of single doses ranging from 0.5 g to 4 g, and after administration of repeated doses of 0.5 g and 2.0 g twice daily. The following PK information (T max , half-life, and clearance) of vigabatrin was obtained from stand-alone PK studies and population PK analyses. Absorption Following oral administration, vigabatrin is essentially completely absorbed. The time to maximum concentration (T max ) is approximately 2.5 hours for infants (5 months to 2 years of age). There was little accumulation with multiple dosing in adult and pediatric patients. A food effect study involving administration of vigabatrin to healthy volunteers under fasting and fed conditions indicated that the C max was decreased by 33%, T max was increased to 2 hours, and AUC was unchanged under fed conditions. Distribution Vigabatrin does not bind to plasma proteins. Vigabatrin is widely distributed throughout the body; mean steady-state volume of distribution is 1.1 L/kg (CV = 20%). Metabolism and Elimination Vigabatrin is not significantly metabolized; it is eliminated primarily through renal excretion. The terminal half-life of vigabatrin is about 5.7 hours for infants (5 months to 2 years of age). Following administration of [14] C-vigabatrin to healthy male volunteers, about 95% of total radioactivity was recovered in the urine over 72 hours with the parent drug representing about 80% of this. Vigabatrin induces CYP2C9 but does not induce other hepatic cytochrome P450 enzyme systems. Specific Populations Pediatric The clearance of vigabatrin is 2.4 L/hr for infants (5 months to 2 years of age). Gender No gender differences were observed for the pharmacokinetic parameters of vigabatrin in patients. Race No specific study was conducted to investigate the effects of race on vigabatrin pharmacokinetics. A cross study comparison between 23 Caucasian and 7 Japanese patients who received 1, 2, and 4 g of vigabatrin indicated that the AUC, C max , and half-life were similar for the two populations. However, the mean renal clearance of Caucasians (5.2 L/hr) was about 25% higher than the Japanese (4.0 L/hr). Inter-subject variability in renal clearance was 20% in Caucasians and was 30% in Japanese. Renal Impairment Mean AUC increased by 30% and the terminal half-life increased by 55% (8.1 hr vs 12.5 hr) in adult patients with mild renal impairment (CLcr from >50 to 80 mL/min) in comparison to normal subjects. Mean AUC increased by two-fold and the terminal half-life increased by two-fold in adult patients with moderate renal impairment (CLcr from >30 to 50 mL/min) in comparison to normal subjects. Mean AUC increased by 4.5-fold and the terminal half-life increased by 3.5-fold in adult patients with severe renal impairment (CLcr from >10 to 30 mL/min) in comparison to normal subjects. The effect of dialysis on VIGAFYDE clearance has not been adequately studied. Infants with Renal Impairment The effect of renal impairment on the pharmacokinetics of VIGAFYDE in infants is unknown. Hepatic Impairment Vigabatrin is not significantly metabolized. The pharmacokinetics of vigabatrin in patients with impaired liver function has not been studied. Drug Interactions Phenytoin A 16% to 20% average reduction in total phenytoin plasma levels was reported in adult controlled clinical studies. In vitro drug metabolism studies indicate that decreased phenytoin concentrations upon addition of vigabatrin therapy are likely to be the result of induction of cytochrome P450 2C enzymes in some patients. Although phenytoin dose adjustments are not routinely required, dose adjustment of phenytoin should be considered if clinically indicated [see Drug Interactions ( 7.1 )]. Clonazepam In a study of 12 healthy adult volunteers, clonazepam (0.5 mg) co-administration had no effect on vigabatrin (1.5 g twice daily) concentrations. Vigabatrin increases the mean C max of clonazepam by 30% and decreases the mean T max by 45% [see Drug Interactions ( 7.1 )]. Other AEDs When co-administered with vigabatrin, phenobarbital concentration (from phenobarbital or primidone) was reduced by an average of 8% to 16%, and sodium valproate plasma concentrations were reduced by an average of 8%. These reductions did not appear to be clinically relevant. Based on population pharmacokinetics, carbamazepine, clorazepate, primidone, and sodium valproate appear to have no effect on plasma concentrations of vigabatrin [see Drug Interactions ( 7.1 )]. Alcohol Co-administration of ethanol (0.6 g/kg) with vigabatrin (1.5 g twice daily) indicated that neither drug influences the pharmacokinetics of the other.

12.1 Mechanism of Action The precise mechanism of vigabatrin’s anti-seizure effect is unknown, but it is believed to be the result of its action as an irreversible inhibitor of γ-aminobutyric acid transaminase (GABA-T), the enzyme responsible for the metabolism of the inhibitory neurotransmitter GABA. This action results in increased levels of GABA in the central nervous system. No direct correlation between plasma concentration and efficacy has been established. The duration of drug effect is presumed to be dependent on the rate of enzyme re-synthesis rather than on the rate of elimination of the drug from the systemic circulation.

12.2 Pharmacodynamics Effects on Electrocardiogram There is no indication of a QT/QTc prolonging effect of vigabatrin in single doses up to 6.0 g. In a randomized, placebo-controlled, crossover study, 58 healthy subjects were administered a single oral dose of vigabatrin (3 g and 6 g) and placebo. Peak concentrations for 6.0 g vigabatrin were approximately 2-fold higher than the peak concentrations following the 3.0 g single oral dose.

12.3 Pharmacokinetics VIGAFYDE is indicated for treatment in patients 1 month to 2 years of age [see Indications and Usage ( 1 )]. VIGAFYDE is not approved for use in adults. Vigabatrin displayed linear pharmacokinetics after administration of single doses ranging from 0.5 g to 4 g, and after administration of repeated doses of 0.5 g and 2.0 g twice daily. The following PK information (T max , half-life, and clearance) of vigabatrin was obtained from stand-alone PK studies and population PK analyses. Absorption Following oral administration, vigabatrin is essentially completely absorbed. The time to maximum concentration (T max ) is approximately 2.5 hours for infants (5 months to 2 years of age). There was little accumulation with multiple dosing in adult and pediatric patients. A food effect study involving administration of vigabatrin to healthy volunteers under fasting and fed conditions indicated that the C max was decreased by 33%, T max was increased to 2 hours, and AUC was unchanged under fed conditions. Distribution Vigabatrin does not bind to plasma proteins. Vigabatrin is widely distributed throughout the body; mean steady-state volume of distribution is 1.1 L/kg (CV = 20%). Metabolism and Elimination Vigabatrin is not significantly metabolized; it is eliminated primarily through renal excretion. The terminal half-life of vigabatrin is about 5.7 hours for infants (5 months to 2 years of age). Following administration of [14] C-vigabatrin to healthy male volunteers, about 95% of total radioactivity was recovered in the urine over 72 hours with the parent drug representing about 80% of this. Vigabatrin induces CYP2C9 but does not induce other hepatic cytochrome P450 enzyme systems. Specific Populations Pediatric The clearance of vigabatrin is 2.4 L/hr for infants (5 months to 2 years of age). Gender No gender differences were observed for the pharmacokinetic parameters of vigabatrin in patients. Race No specific study was conducted to investigate the effects of race on vigabatrin pharmacokinetics. A cross study comparison between 23 Caucasian and 7 Japanese patients who received 1, 2, and 4 g of vigabatrin indicated that the AUC, C max , and half-life were similar for the two populations. However, the mean renal clearance of Caucasians (5.2 L/hr) was about 25% higher than the Japanese (4.0 L/hr). Inter-subject variability in renal clearance was 20% in Caucasians and was 30% in Japanese. Renal Impairment Mean AUC increased by 30% and the terminal half-life increased by 55% (8.1 hr vs 12.5 hr) in adult patients with mild renal impairment (CLcr from >50 to 80 mL/min) in comparison to normal subjects. Mean AUC increased by two-fold and the terminal half-life increased by two-fold in adult patients with moderate renal impairment (CLcr from >30 to 50 mL/min) in comparison to normal subjects. Mean AUC increased by 4.5-fold and the terminal half-life increased by 3.5-fold in adult patients with severe renal impairment (CLcr from >10 to 30 mL/min) in comparison to normal subjects. The effect of dialysis on VIGAFYDE clearance has not been adequately studied. Infants with Renal Impairment The effect of renal impairment on the pharmacokinetics of VIGAFYDE in infants is unknown. Hepatic Impairment Vigabatrin is not significantly metabolized. The pharmacokinetics of vigabatrin in patients with impaired liver function has not been studied. Drug Interactions Phenytoin A 16% to 20% average reduction in total phenytoin plasma levels was reported in adult controlled clinical studies. In vitro drug metabolism studies indicate that decreased phenytoin concentrations upon addition of vigabatrin therapy are likely to be the result of induction of cytochrome P450 2C enzymes in some patients. Although phenytoin dose adjustments are not routinely required, dose adjustment of phenytoin should be considered if clinically indicated [see Drug Interactions ( 7.1 )]. Clonazepam In a study of 12 healthy adult volunteers, clonazepam (0.5 mg) co-administration had no effect on vigabatrin (1.5 g twice daily) concentrations. Vigabatrin increases the mean C max of clonazepam by 30% and decreases the mean T max by 45% [see Drug Interactions ( 7.1 )]. Other AEDs When co-administered with vigabatrin, phenobarbital concentration (from phenobarbital or primidone) was reduced by an average of 8% to 16%, and sodium valproate plasma concentrations were reduced by an average of 8%. These reductions did not appear to be clinically relevant. Based on population pharmacokinetics, carbamazepine, clorazepate, primidone, and sodium valproate appear to have no effect on plasma concentrations of vigabatrin [see Drug Interactions ( 7.1 )]. Alcohol Co-administration of ethanol (0.6 g/kg) with vigabatrin (1.5 g twice daily) indicated that neither drug influences the pharmacokinetics of the other.

20241107

12

3 DOSAGE FORMS AND STRENGTHS Oral Solution : 100 mg/mL clear, colorless to light yellow solution with a peppermint odor. Oral Solution : 100 mg/mL ( 3 )

VIGAFYDE vigabatrin VIGABATRIN VIGABATRIN clear, colorless to light yellow

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenesis Vigabatrin showed no carcinogenic potential in mouse or rat when given in the diet at doses up to 150 mg/kg/day for 18 months (mouse) or at doses up to 150 mg/kg/day for 2 years (rat). These doses are less than the maximum recommended human dose (MRHD) for infantile spasms (150 mg/kg/day). Mutagenesis Vigabatrin was negative in in vitro (Ames, CHO/HGPRT mammalian cell forward gene mutation, chromosomal aberration in rat lymphocytes) and in in viv o (mouse bone marrow micronucleus) assays. Impairment of Fertility No adverse effects on male or female fertility were observed in rats at oral doses up to 150 mg/kg/day.

13 NONCLINICAL TOXICOLOGY 13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenesis Vigabatrin showed no carcinogenic potential in mouse or rat when given in the diet at doses up to 150 mg/kg/day for 18 months (mouse) or at doses up to 150 mg/kg/day for 2 years (rat). These doses are less than the maximum recommended human dose (MRHD) for infantile spasms (150 mg/kg/day). Mutagenesis Vigabatrin was negative in in vitro (Ames, CHO/HGPRT mammalian cell forward gene mutation, chromosomal aberration in rat lymphocytes) and in in viv o (mouse bone marrow micronucleus) assays. Impairment of Fertility No adverse effects on male or female fertility were observed in rats at oral doses up to 150 mg/kg/day.

NDA217684

VIGAFYDE

vigabatrin

80789-003

HUMAN PRESCRIPTION DRUG

ORAL

PRINCIPAL DISPLAY PANEL NDC 80789-003-15 VIGAFYDE ™ (vigabatrin oral solution) 100 mg/mL 150 mL carton Rx Only Add image transcription here... NDC 80789-003-15 vigafyde bottle label

17 PATIENT COUNSELING INFORMATION Advise caregivers to read the FDA-approved patient labeling ( Medication Guide and Instructions for Use ). If a patient is switching from vigabatrin powder for oral solution, inform the caregiver that VIGAFYDE is more concentrated (100 mg/mL) compared to reconstituted solutions of vigabatrin powder for oral solution (50 mg/mL), and the volume of solution that should be given to their infant will be lower than previously prescribed. Advise patients to stop using other products that contain vigabatrin. Administration Instructions for VIGAFYDE Oral Solution Physicians should confirm that caregiver(s) understand how to measure and administer the correct dose of VIGAFYDE oral solution to their infants. Instruct caregivers that VIGAFYDE should not be diluted prior to dosing. Advise caregivers to measure VIGAFYDE with the syringe provided by the pharmacy. A household teaspoon is not an accurate measuring device. Advise the caregiver to discard any remaining VIGAFYDE 90 days after first opening. Permanent Vision Loss Inform caregivers of the risk of permanent vision loss, particularly loss of peripheral vision, from VIGAFYDE, and the need for monitoring vision [see Warnings and Precautions ( 5.1 )] . Monitoring of vision, including assessment of visual fields and visual acuity, is recommended at baseline (no later than 4 weeks after starting VIGAFYDE), at least every 3 months while on therapy, and about 3-6 months after discontinuation of therapy. In patients for whom vision testing is not possible, treatment may continue without recommended testing according to clinical judgment with appropriate caregiver counseling. Caregivers should be informed that if baseline or subsequent vision is not normal, VIGAFYDE should only be used if the benefits of VIGAFYDE treatment clearly outweigh the risks of additional vision loss. Advise caregivers that vision testing may be insensitive and may not detect vision loss before it is severe. Also advise patients and caregivers that if vision loss is documented, such loss is irreversible. Ensure that both of these points are understood by patients and caregivers. Caregivers should be informed that if changes in vision are suspected, they should notify their physician immediately. VIGABATRIN REMS VIGAFYDE is available only through a restricted program called the Vigabatrin REMS [see Warnings and Precautions ( 5.2 )] . Inform caregivers of the following: Patients/caregivers must be enrolled in the program. VIGAFYDE is only available through pharmacies that are enrolled in the Vigabatrin REMS. MRI Abnormalities in Infants Inform caregiver(s) of the possibility that infants may develop an abnormal MRI signal of unknown clinical significance [see Warnings and Precautions ( 5.3 )] . Withdrawal of VIGAFYDE Therapy Instruct patients and caregivers not to suddenly discontinue VIGAFYDE therapy without consulting with their healthcare provider. As with all AEDs, withdrawal should normally be gradual [see Warnings and Precautions ( 5.5 )] . Made in the United Kingdom Manufactured for PYROS PHARMACEUTICALS, INC Parsippany, NJ 07054 U.S.A. VIGAFYDE is a registered trademark of Pyros Pharmaceuticals, Inc. L3006 Rev 2.0 pyros logo

MEDICATION GUIDE VIGAFYDE ™ ( VIG- uh-fide ) (vigabatrin) oral solution What is the most important information I should know about VIGAFYDE? VIGAFYDE can cause serious side effects, including: Permanent vision loss Magnetic resonance imaging (MRI) changes in babies with infantile spasms (IS) 1. Permanent vision loss: VIGAFYDE can damage the vision of anyone who takes it. Some people can have severe loss particularly to their ability to see to the side when they look straight ahead (peripheral vision). With severe vision loss, your baby may only be able to see things straight in front of them (sometimes called “tunnel vision”). Your baby may also have blurry vision. If this happens, it will not get better. Vision loss in babies: Because of the risk of vision loss, VIGAFYDE is used in babies 1 month to 2 years of age with IS only when you and your baby's healthcare provider decide that the possible benefits of VIGAFYDE are more important than the risks. Parents or caregivers are not likely to recognize the symptoms of vision loss in babies until it is severe. Healthcare providers may not find vision loss in babies until it is severe. It is difficult to test vision in babies, but, to the extent possible, all babies should have their vision tested before starting VIGAFYDE or within 4 weeks after starting VIGAFYDE, and every 3 months after that until VIGAFYDE is stopped. Your baby should also have a vision test about 3 to 6 months after VIGAFYDE is stopped. Your baby may not be able to be tested. Your baby's healthcare provider will determine if your baby can be tested. If your baby cannot be tested, your baby's healthcare provider may continue prescribing VIGAFYDE, but your baby's healthcare provider will not be able to watch for any vision loss. Tell your healthcare provider right away if you think that your baby is: not seeing as well as before taking VIGAFYDE acting differently than normal Even if your baby’s vision seems fine, it is important to get regular vision tests because damage can happen before your baby acts differently. Even these regular vision exams may not show the damage to your baby’s vision before it is severe and permanent. Because VIGAFYDE might cause permanent vision loss, it is available to healthcare providers and patients only under a special program called the Vigabatrin Risk Evaluation and Mitigation Strategy (REMS). VIGAFYDE can only be prescribed to people who are enrolled in this program. As part of the Vigabatrin REMS, it is recommended that your baby's healthcare provider test your baby's vision from time to time (periodically) while your baby is being treated with VIGAFYDE, and even after your baby stops treatment. Your baby's healthcare provider will explain the details of the Vigabatrin REMS to you. For more information, go to www.vigabatrinREMS.com or call 1-866-244-8175. 2. MRI changes in babies with IS: Brain pictures taken by MRI show changes in some babies after they are given VIGAFYDE. It is not known if these changes are harmful. What is VIGAFYDE? VIGAFYDE is a prescription medicine used to treat babies 1 month to 2 years of age who have infantile spasms (IS) if you and your baby’s healthcare provider decide the possible benefits of taking VIGAFYDE are more important than the possible risk of vision loss. What should I tell my baby's healthcare provider before starting VIGAFYDE? If you are a parent or caregiver whose baby has IS, before giving VIGAFYDE to your baby, tell your baby's healthcare provider about all of your baby’s medical conditions, including if your baby has or ever had: an allergic reaction to VIGAFYDE, such as hives, itching, or trouble breathing any vision problems any kidney problems Tell your healthcare provider about all the medicines your baby takes, including prescription and over-the-counter medicines, vitamins, and herbal supplements. VIGAFYDE and other medicines may affect each other causing side effects. How should my baby take VIGAFYDE? VIGAFYDE comes as an oral solution. Important: VIGAFYDE is more concentrated than vigabatrin solutions prepared from powder. The volume of VIGAFYDE solution prescribed by your baby’s healthcare provider may be less than the volume prescribed for other vigabatrin solutions prepared from powder. Always double check the volume (mL) that you are to give your baby when you get a new prescription filled. Your baby will receive VIGAFYDE from a specialty pharmacy. Give VIGAFYDE exactly as your baby's healthcare provider tells you to. VIGAFYDE is usually taken 2 times each day. VIGAFYDE may be taken with or without food. Before starting to give VIGAFYDE, talk to your baby’s healthcare provider about what you should do if a VIGAFYDE dose is missed. If your baby is taking VIGAFYDE for IS and the seizures do not improve within 2 to 4 weeks, your baby’s healthcare provider will stop prescribing VIGAFYDE. Do not stop taking VIGAFYDE suddenly . This can cause serious problems. Stopping VIGAFYDE or any seizure medicine suddenly can cause seizures that will not stop (status epilepticus) in people who are being treated for seizures. You should follow your baby's healthcare provider’s instructions on how to stop taking VIGAFYDE. Tell your baby’s healthcare provider right away about any increase in seizures when VIGAFYDE treatment is being stopped . Before your baby starts taking VIGAFYDE, speak to your baby’s healthcare provider about what to do if your baby misses a dose, vomits, spits up, or only takes part of the dose of VIGAFYDE. Do not stop taking VIGAFYDE without talking to your healthcare provider . If VIGAFYDE improves your baby’s seizures, you and your baby's healthcare provider should talk about whether the benefit of taking VIGAFYDE is more important than the risk of vision loss, and decide if your baby will continue to take VIGAFYDE. VIGAFYDE can be given to your baby at the same time as their meal. Measure the dose of VIGAFYDE using the syringe given to you by the pharmacy. A household teaspoon is not an accurate measuring device. Do not add water or other liquids to VIGAFYDE (do not dilute) when measuring the dose. See “Instructions for Use” for detailed information about how to give VIGAFYDE to your baby the right way. What are the possible side effects of VIGAFYDE? VIGAFYDE can cause serious side effects, including: See “ What is the most important information I should know about VIGAFYDE?” VIGAFYDE may cause your baby to be sleepy . Sleepy babies may have a harder time suckling and feeding, or may be irritable. weight gain that happens without swelling The following serious side effects happen in adults who take vigabatrin (the active ingredient in VIGAFYDE). It is not known if these side effects also happen in babies who take VIGAFYDE. low red blood cell counts (anemia). nerve problems. Symptoms of a nerve problem can include numbness and tingling in toes or feet. It is not known if nerve problems will go away after treatment with VIGAFYDE is stopped. swelling. suicidal thoughts and ideation. VIGAFYDE may make certain types of seizures worse. You should tell your baby’s healthcare provider right away if your baby’s seizures get worse. Tell your baby’s healthcare provider if you see any changes in your baby’s behavior. The most common side effects of VIGAFYDE in babies include: sleepiness – VIGAFYDE may cause your baby to be sleepy. Sleepy babies may have a harder time suckling and feeding or may be irritable. ear infection swelling in the bronchial tubes (bronchitis) irritability Tell your healthcare provider if your baby has any side effect that bothers them or that does not go away. These are not all the possible side effects of VIGAFYDE. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. How should I store VIGAFYDE? Store unopened bottles at room temperature between 68°F to 77°F (20°C to 25°C). Once opened, store bottle in a refrigerator or at room temperature between 36°F to 86°F (2°C to 30°C). Throw away (discard) any opened bottle of VIGAFYDE 90 days after first opening, even if there is still medicine in the bottle. Keep VIGAFYDE and all medicines out of the reach of children. General information about the safe and effective use of VIGAFYDE. Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. You can ask your pharmacist or healthcare provider for information about VIGAFYDE that is written for health professionals. Do not use VIGAFYDE for a condition for which it was not prescribed. Do not give VIGAFYDE to other people, even if they have the same symptoms. It may harm them. What are the ingredients in VIGAFYDE? Active Ingredient: vigabatrin Inactive Ingredients: methylparaben, peppermint flavor, propylparaben, purified water, and sucralose Made in the United Kingdom for: PYROS PHARMACEUTICALS, INC Parsippany, NJ 07054 U.S.A. VIGAFYDE is a registered trademark of Pyros For more information, go to www.VIGAFYDE.com or call 1-855-406-1010 . This Medication Guide has been approved by the U.S. Food and Drug Administration. L3006 Rev 2.0 Revised 7/2024 All people who take VIGAFYDE

14 CLINICAL STUDIES The efficacy of VIGAFYDE is based upon a comparison of the compositional differences between vigabatrin for oral solution and VIGAFYDE oral solution. The effectiveness of vigabatrin as monotherapy was established for infantile spasms in two multicenter controlled studies. Both studies were similar in terms of disease characteristics and prior treatments of patients and all enrolled infants had a confirmed diagnosis of infantile spasms. Study 1 Study 1 (N=221) was a multicenter, randomized, low-dose high-dose, parallel-group, partially-blind (caregivers knew the actual dose but not whether their child was classified as low or high dose; EEG reader was blinded but investigators were not blinded) study to evaluate the safety and efficacy of vigabatrin in patients ˂2 years of age with new-onset infantile spasms. Patients with both symptomatic and cryptogenic etiologies were studied. The study was comprised of two phases. The first phase was a 14 to 21 day partially-blind phase in which patients were randomized to receive either low-dose (18-36 mg/kg/day) or high-dose (100-148 mg/kg/day) vigabatrin. Study drug was titrated over 7 days, followed by a constant dose for 7 days. If the patient became spasm-free on or before day 14, another 7 days of constant dose was administered. The primary efficacy endpoint of this study was the proportion of patients who were spasm-free for 7 consecutive days beginning within the first 14 days of vigabatrin therapy. Patients considered spasm-free were defined as those patients who remained free of spasms (evaluated according to caregiver response to direct questioning regarding spasm frequency) and who had no indication of spasms or hypsarrhythmia during 8 hours of closed-circuit television EEG recording (including at least one sleep-wake-sleep cycle) performed within 3 days of the seventh day of spasm freedom and interpreted by a blinded EEG reader. Seventeen patients in the high-dose group achieved spasm freedom compared with 8 patients in the low dose group. This difference was statistically significant (p=0.0375). Primary efficacy results are shown in Table 3. Table 3. Spasm Freedom by Primary Criteria (Study 1) Vigabatrin Treatment Group 18-36 mg/kg/day [N=114] n (%) 100-148 mg/kg/day [N=107] n (%) Patients who Achieved Spasm Freedom 8 (7.0) 17 (15.9) p=0.0375 Note: Primary criteria were evaluated based on caregiver assessment plus CCTV EEG confirmation within 3 days of the seventh day of spasm freedom. Study 2 Study 2 (N=40) was a multicenter, randomized, double-blind, placebo-controlled, parallel-group study consisting of a pre-treatment (baseline) period of 2-3 days, followed by a 5-day double-blind treatment phase during which patients were treated with vigabatrin (initial dose of 50 mg/kg/day with titration allowed to 150 mg/kg/day) or placebo. The primary efficacy endpoint in this study was the average percent change in daily spasm frequency, assessed during a pre-defined and consistent 2-hour window of evaluation, comparing baseline to the final 2 days of the 5-day double-blind treatment phase. No statistically significant differences were observed in the average frequency of spasms using the 2-hour evaluation window. However, a post-hoc alternative efficacy analysis, using a 24-hour clinical evaluation window found a statistically significant difference in the overall percentage of reductions in spasms between the vigabatrin group (68.9%) and the placebo group (17.0%) (p=0.030). Duration of therapy for infantile spasms was evaluated in a post hoc analysis of a Canadian Pediatric Epilepsy Network (CPEN) study of developmental outcomes in infantile spasms patients. The 38/68 infants in the study who had responded to vigabatrin therapy (complete cessation of spasms and hypsarrhythmia) continued vigabatrin therapy for a total duration of 6 months therapy. The 38 infants who responded were then followed for an additional 18 months after discontinuation of vigabatrin to determine their clinical outcome. A post hoc analysis indicated no observed recurrence of infantile spasms in any of these 38 infants.

8.5 Geriatric Use VIGAFYDE is indicated for treatment in patients 1 month to 2 years of age [see Indications and Usage ( 1 )]. VIGAFYDE is not approved for use in adults. Clinical studies of vigabatrin did not include sufficient numbers of patients aged 65 and over to determine whether they responded differently from younger patients. Vigabatrin is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function. Oral administration of a single dose of 1.5 g of vigabatrin to elderly (≥65 years) patients with reduced creatinine clearance (<50 mL/min) was associated with moderate to severe sedation and confusion in 4 of 5 patients, lasting up to 5 days. The renal clearance of vigabatrin was 36% lower in healthy elderly subjects (≥65 years) than in young healthy males. If used in elderly patients, adjustment of dose or frequency of administration should be considered. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.

8.4 Pediatric Use The safety and effectiveness of vigabatrin as monotherapy for pediatric patients with infantile spasms (1 month to 2 years of age) have been established [see Dosage and Administration ( 2.2 ) and Clinical Studies ( 14.1 )]. Safety and effectiveness as a monotherapy for the treatment of infantile spasms in pediatric patients below the age of 1 month have not been established. Duration of therapy for infantile spasms was evaluated in a post hoc analysis of a Canadian Pediatric Epilepsy Network (CPEN) study of developmental outcomes in infantile spasms patients. This analysis suggests that a total duration of 6 months of vigabatrin therapy is adequate for the treatment of infantile spasms. However, prescribers must use their clinical judgment as to the most appropriate duration of use [see Clinical Studies ( 14.1 )]. Abnormal MRI signal changes and Intramyelinic Edema (IME) in infants and young children being treated with vigabatrin have been observed [see Warnings and Precautions ( 5.3, 5.4 )]. Juvenile Animal Toxicity Data Oral administration of vigabatrin (5, 15, or 50 mg/kg/day) to young rats during the neonatal and juvenile periods of development (postnatal days 4-65) produced neurobehavioral (convulsions, neuromotor impairment, learning deficits) and neurohistopathological (brain gray matter vacuolation, decreased myelination, and retinal dysplasia) abnormalities. The no-effect dose for developmental neurotoxicity in juvenile rats (the lowest dose tested) was associated with plasma vigabatrin exposures (AUC) substantially less than those measured in pediatric patients at recommended doses. In dogs, oral administration of vigabatrin (30 or 100 mg/kg/day) during selected periods of juvenile development (postnatal days 22-112) produced neurohistopathological abnormalities (brain gray matter vacuolation). Neurobehavioral effects of vigabatrin were not assessed in the juvenile dog. A no-effect dose for neurohistopathology was not established in juvenile dogs; the lowest effect dose (30 mg/kg/day) was associated with plasma vigabatrin exposures lower than those measured in pediatric patients at recommended doses [see Warnings and Precautions ( 5.4 )].

8.1 Pregnancy VIGAFYDE is indicated for treatment in patients 1 month to 2 years of age [see Indications and Usage ( 1 )]. VIGAFYDE is not approved for use in adolescents and adults. Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to AEDs, including VIGAFYDE, during pregnancy. Encourage women who are taking VIGAFYDE during pregnancy to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry. This can be done by calling the toll-free number 1-888-233-2334 or visiting the website, http://www.aedpregnancyregistry.org/ . This must be done by the patient herself. Risk Summary There are no adequate data on the developmental risk associated with the use of VIGAFYDE in pregnant women. Limited available data from case reports and cohort studies pertaining to vigabatrin use in pregnant women have not established a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. However, based on animal data, VIGAFYDE use in pregnant women may result in fetal harm. When administered to pregnant animals, vigabatrin produced developmental toxicity, including an increase in fetal malformations and offspring neurobehavioral and neurohistopathological effects, at clinically relevant doses. In addition, developmental neurotoxicity was observed in rats treated with vigabatrin during a period of postnatal development corresponding to the third trimester of human pregnancy (see Data). 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 Administration of vigabatrin (oral doses of 50 to 200 mg/kg/day) to pregnant rabbits throughout the period of organogenesis was associated with an increased incidence of malformations (cleft palate) and embryofetal death; these findings were observed in two separate studies. The no-effect dose for adverse effects on embryofetal development in rabbits (100 mg/kg/day) is approximately 1/2 the maximum recommended human dose (MRHD) of 3 g/day on a body surface area (mg/m2) basis. In rats, oral administration of vigabatrin (50, 100, or 150 mg/kg/day) throughout organogenesis resulted in decreased fetal body weights and increased incidences of fetal anatomic variations. The no-effect dose for adverse effects on embryo-fetal development in rats (50 mg/kg/day) is approximately 1/5 the MRHD on a mg/m2 basis. Oral administration of vigabatrin (50, 100, 150 mg/kg/day) to rats from the latter part of pregnancy through weaning produced long-term neurohistopathological (hippocampal vacuolation) and neurobehavioral (convulsions) abnormalities in the offspring. A no-effect dose for developmental neurotoxicity in rats was not established; the low-effect dose (50 mg/kg/day) is approximately 1/5 the MRHD on a mg/m2 basis. In a published study, vigabatrin (300 or 450 mg/kg) was administered by intraperitoneal injection to a mutant mouse strain on a single day during organogenesis (day 7, 8, 9, 10, 11, or 12). An increase in fetal malformations (including cleft palate) was observed at both doses. Oral administration of vigabatrin (5, 15, or 50 mg/kg/day) to young rats during the neonatal and juvenile periods of development (postnatal days 4-65) produced neurobehavioral (convulsions, neuromotor impairment, learning deficits) and neurohistopathological (brain vacuolation, decreased myelination, and retinal dysplasia) abnormalities in treated animals. 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 juvenile rats (5 mg/kg/day) was associated with plasma vigabatrin exposures (AUC) less than 1/30 of those measured in pediatric patients receiving an oral dose of 50 mg/kg.

8 USE IN SPECIFIC POPULATIONS 8.1 Pregnancy VIGAFYDE is indicated for treatment in patients 1 month to 2 years of age [see Indications and Usage ( 1 )]. VIGAFYDE is not approved for use in adolescents and adults. Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to AEDs, including VIGAFYDE, during pregnancy. Encourage women who are taking VIGAFYDE during pregnancy to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry. This can be done by calling the toll-free number 1-888-233-2334 or visiting the website, http://www.aedpregnancyregistry.org/ . This must be done by the patient herself. Risk Summary There are no adequate data on the developmental risk associated with the use of VIGAFYDE in pregnant women. Limited available data from case reports and cohort studies pertaining to vigabatrin use in pregnant women have not established a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. However, based on animal data, VIGAFYDE use in pregnant women may result in fetal harm. When administered to pregnant animals, vigabatrin produced developmental toxicity, including an increase in fetal malformations and offspring neurobehavioral and neurohistopathological effects, at clinically relevant doses. In addition, developmental neurotoxicity was observed in rats treated with vigabatrin during a period of postnatal development corresponding to the third trimester of human pregnancy (see Data). 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 Administration of vigabatrin (oral doses of 50 to 200 mg/kg/day) to pregnant rabbits throughout the period of organogenesis was associated with an increased incidence of malformations (cleft palate) and embryofetal death; these findings were observed in two separate studies. The no-effect dose for adverse effects on embryofetal development in rabbits (100 mg/kg/day) is approximately 1/2 the maximum recommended human dose (MRHD) of 3 g/day on a body surface area (mg/m2) basis. In rats, oral administration of vigabatrin (50, 100, or 150 mg/kg/day) throughout organogenesis resulted in decreased fetal body weights and increased incidences of fetal anatomic variations. The no-effect dose for adverse effects on embryo-fetal development in rats (50 mg/kg/day) is approximately 1/5 the MRHD on a mg/m2 basis. Oral administration of vigabatrin (50, 100, 150 mg/kg/day) to rats from the latter part of pregnancy through weaning produced long-term neurohistopathological (hippocampal vacuolation) and neurobehavioral (convulsions) abnormalities in the offspring. A no-effect dose for developmental neurotoxicity in rats was not established; the low-effect dose (50 mg/kg/day) is approximately 1/5 the MRHD on a mg/m2 basis. In a published study, vigabatrin (300 or 450 mg/kg) was administered by intraperitoneal injection to a mutant mouse strain on a single day during organogenesis (day 7, 8, 9, 10, 11, or 12). An increase in fetal malformations (including cleft palate) was observed at both doses. Oral administration of vigabatrin (5, 15, or 50 mg/kg/day) to young rats during the neonatal and juvenile periods of development (postnatal days 4-65) produced neurobehavioral (convulsions, neuromotor impairment, learning deficits) and neurohistopathological (brain vacuolation, decreased myelination, and retinal dysplasia) abnormalities in treated animals. 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 juvenile rats (5 mg/kg/day) was associated with plasma vigabatrin exposures (AUC) less than 1/30 of those measured in pediatric patients receiving an oral dose of 50 mg/kg. 8.2 Lactation VIGAFYDE is indicated for treatment in patients 1 month to 2 years of age [see Indications and Usage ( 1 )]. VIGAFYDE is not approved for use in adolescents and adults. Risk Summary Vigabatrin is excreted in human milk. The effects of vigabatrin on the breastfed infant and on milk production are unknown. Because of the potential for serious adverse reactions from vigabatrin in nursing infants, breastfeeding is not recommended. If exposing a breastfed infant to VIGAFYDE, observe for any potential adverse effects [see Warnings and Precautions ( 5.1, 5.3, 5.4, 5.8 )]. 8.4 Pediatric Use The safety and effectiveness of vigabatrin as monotherapy for pediatric patients with infantile spasms (1 month to 2 years of age) have been established [see Dosage and Administration ( 2.2 ) and Clinical Studies ( 14.1 )]. Safety and effectiveness as a monotherapy for the treatment of infantile spasms in pediatric patients below the age of 1 month have not been established. Duration of therapy for infantile spasms was evaluated in a post hoc analysis of a Canadian Pediatric Epilepsy Network (CPEN) study of developmental outcomes in infantile spasms patients. This analysis suggests that a total duration of 6 months of vigabatrin therapy is adequate for the treatment of infantile spasms. However, prescribers must use their clinical judgment as to the most appropriate duration of use [see Clinical Studies ( 14.1 )]. Abnormal MRI signal changes and Intramyelinic Edema (IME) in infants and young children being treated with vigabatrin have been observed [see Warnings and Precautions ( 5.3, 5.4 )]. Juvenile Animal Toxicity Data Oral administration of vigabatrin (5, 15, or 50 mg/kg/day) to young rats during the neonatal and juvenile periods of development (postnatal days 4-65) produced neurobehavioral (convulsions, neuromotor impairment, learning deficits) and neurohistopathological (brain gray matter vacuolation, decreased myelination, and retinal dysplasia) abnormalities. The no-effect dose for developmental neurotoxicity in juvenile rats (the lowest dose tested) was associated with plasma vigabatrin exposures (AUC) substantially less than those measured in pediatric patients at recommended doses. In dogs, oral administration of vigabatrin (30 or 100 mg/kg/day) during selected periods of juvenile development (postnatal days 22-112) produced neurohistopathological abnormalities (brain gray matter vacuolation). Neurobehavioral effects of vigabatrin were not assessed in the juvenile dog. A no-effect dose for neurohistopathology was not established in juvenile dogs; the lowest effect dose (30 mg/kg/day) was associated with plasma vigabatrin exposures lower than those measured in pediatric patients at recommended doses [see Warnings and Precautions ( 5.4 )]. 8.5 Geriatric Use VIGAFYDE is indicated for treatment in patients 1 month to 2 years of age [see Indications and Usage ( 1 )]. VIGAFYDE is not approved for use in adults. Clinical studies of vigabatrin did not include sufficient numbers of patients aged 65 and over to determine whether they responded differently from younger patients. Vigabatrin is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function. Oral administration of a single dose of 1.5 g of vigabatrin to elderly (≥65 years) patients with reduced creatinine clearance (<50 mL/min) was associated with moderate to severe sedation and confusion in 4 of 5 patients, lasting up to 5 days. The renal clearance of vigabatrin was 36% lower in healthy elderly subjects (≥65 years) than in young healthy males. If used in elderly patients, adjustment of dose or frequency of administration should be considered. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. 8.6 Renal Impairment Information about how to adjust the dose in infants with renal impairment is unavailable.

16 HOW SUPPLIED/STORAGE AND HANDLING 16.1 How Supplied VIGAFYDE (vigabatrin oral solution) contains 100 mg/mL vigabatrin. It is a clear, colorless to light yellow, peppermint-flavored solution supplied in a white opaque high-density polyethylene (HDPE) 150 mL bottle in a carton (NDC 80789-003-15). 16.2 Storage and Handling Store unopened bottles at room temperature between 20°C to 25°C (68°F to 77°F) with excursions permitted to 15°C to 30°C (59°F to 86°F) [See USP Controlled Room Temperature]. Once opened, store bottle in a refrigerator or at room temperature between 2°C to 30°C (36°F to 86°F). Discard the unused portion 90 days after first opening.

16.2 Storage and Handling Store unopened bottles at room temperature between 20°C to 25°C (68°F to 77°F) with excursions permitted to 15°C to 30°C (59°F to 86°F) [See USP Controlled Room Temperature]. Once opened, store bottle in a refrigerator or at room temperature between 2°C to 30°C (36°F to 86°F). Discard the unused portion 90 days after first opening.

WARNING: PERMANENT VISION LOSS VIGAFYDE can cause permanent bilateral concentric visual field constriction, including tunnel vision that can result in disability. In some cases, VIGAFYDE also can damage the central retina and may decrease visual acuity [see Warnings and Precautions ( 5.1 )]. The onset of vision loss from VIGAFYDE is unpredictable and can occur within weeks of starting treatment or sooner, or at any time after starting treatment, even after months or years. Symptoms of vision loss from VIGAFYDE are unlikely to be recognized by patients or caregivers before vision loss is severe. Vision loss of milder severity, while often unrecognized by the patient or caregiver, can still adversely affect function. The risk of vision loss increases with increasing dose and cumulative exposure, but there is no dose or exposure known to be free of risk of vision loss. Vision assessment is recommended at baseline (no later than 4 weeks after starting VIGAFYDE), at least every 3 months during therapy, and about 3 to 6 months after the discontinuation of therapy. Once detected, vision loss due to VIGAFYDE is not reversible. It is expected that, even with frequent monitoring, some patients will develop severe vision loss. Consider drug discontinuation, balancing benefit and risk, if vision loss is documented. Risk of new or worsening vision loss continues as long as VIGAFYDE is used. It is possible that vision loss can worsen despite discontinuation of VIGAFYDE. Because of the risk of vision loss, VIGAFYDE should be withdrawn from patients with infantile spasms who fail to show substantial clinical benefit within 2-4 weeks of initiation, or sooner if treatment failure becomes obvious. Patient response to and continued need for VIGAFYDE should be periodically reassessed. VIGAFYDE should not be used in patients with, or at high risk of, other types of irreversible vision loss unless the benefits of treatment clearly outweigh the risks. VIGAFYDE should not be used with other drugs associated with serious adverse ophthalmic effects such as retinopathy or glaucoma unless the benefits clearly outweigh the risks. Use the lowest dosage and shortest exposure to VIGAFYDE consistent with clinical objectives [see Dosage and Administration ( 2.1 )]. Because of the risk of permanent vision loss, VIGAFYDE is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS) called the Vigabatrin REMS [see Warnings and Precautions ( 5.1 ) ]. Further information is available at www.vigabatrinREMS.com or call 1 -866-244-8175. WARNING: PERMANENT VISION LOSS See full prescribing information for complete boxed warning. VIGAFYDE can cause permanent bilateral concentric visual field constriction, including tunnel vision that can result in disability. In some cases, VIGAFYDE may also decrease visual acuity ( 5.1 ). Risk increases with increasing dose and cumulative exposure, but there is no dose or exposure to VIGAFYDE known to be free of risk of vision loss ( 5.1 ). Risk of new and worsening vision loss continues as long as VIGAFYDE is used, and possibly after discontinuing VIGAFYDE ( 5.1 ). Baseline and periodic vision assessment is recommended for patients on VIGAFYDE. However, this assessment cannot always prevent vision damage ( 5.1 ). VIGAFYDE is available only through a restricted program called the Vigabatrin REMS ( 5.2 ).