DALFAMPRIDINE tablet, extended release
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1. Dalfampridine Extended-release Tablets?
2. , Tell Your Doctor If You:
3. Serious Allergic Reactions. Stop Taking Dalfampridine Extended-release Tablets And Call Your Doctor Right Away Or Get Emergency Medical Help If You Have:
4. Active Ingredient:
5. Inactive Ingredients:
6. Manufactured By:
7. Manufactured For:
8. Patient Information

Dalfampridine Extended-release Tablets? ⮝

Dalfampridine extended-release tablets can cause seizures.

• You could have a seizure even if you never had a seizure before.
• Your chance of having a seizure is higher if you take too much dalfampridine extended-release tablets or if your kidneys have a mild decrease of function, which is common after age 50.
• Your doctor may do a blood test to check how well your kidneys are working, if that is not known before you start taking dalfampridine extended-release tablets.
• Do not take dalfampridine extended-release tablets if you have ever had a seizure.
• Before taking dalfampridine extended-release tablets tell your doctor if you have kidney problems.
• Take dalfampridine extended-release tablets exactly as prescribed by your doctor.

  Dalfampridine extended-release tablets are a prescription medicine used to help improve walking in adults with multiple sclerosis (MS). This was shown by an increase in walking speed.

  
  

  It is not known if dalfampridine extended-release tablet is safe or effective in children less than 18 years of age.

  Who should not take

, Tell Your Doctor If You: ⮝

• have any other medical conditions
• are taking compounded 4-aminopyridine (fampridine, 4-AP)
• are taking any other medicines, including over-the-counter medicines such as cimetidine
• are pregnant or plan to become pregnant. It is not known if dalfampridine will harm your unborn baby. You and your doctor will decide if you should take dalfampridine extended-release tablets while you are pregnant
• are breast-feeding or plan to breast-feed. It is not known if dalfampridine passes into your breast milk. You and your doctor should decide if you will take dalfampridine extended-release tablets or breast-feed. You should not do both.

Tell your doctor about all the medicines you take,including prescription and non-prescription medicines, vitamins and herbal supplements.

Know the medicines you take. Keep a list of them and show it to your doctor and pharmacist when you get a new medicine.

How should I takedalfampridine extended-release tablets?

• Take dalfampridine extended-release tablets exactly as your doctor tells you to take it. Do not change your dose of dalfampridine extended-release tablets.
• Take one dalfampridine extended-release tablets 2 times each day about 12 hours apart. Do not take more than 2 tablets of dalfampridine extended-release tablets in a 24-hour period.
• Takedalfampridine extended-release tabletswhole. Do not break, crush, chew or dissolvedalfampridine extended-release tabletsbefore swallowing. If you cannot swallowdalfampridine extended-release tabletswhole, tell your doctor.
• Dalfampridine extended-release tablet is released slowly over time. If the tablet is broken, the medicine may be released too fast. This can raise your chance of having a seizure.
• Dalfampridine extended release tablets can be taken with or without food.
• If you miss a dose of dalfampridine extended-release tablets, do not make up the missed dose. Do not take 2 doses at the same time. Take your next dose at your regular scheduled time.
• If you take too much dalfampridine extended-release tablet, call your doctor or go to the nearest hospital emergency room right away.
• Do not take dalfampridine extended-release tablets together with other aminopyridine medications, including compounded 4-AP (sometimes called 4-aminopyridine, fampridine).

What are the possible side effects ofdalfampridine extended-release tablets?

Dalfampridine extended-release tablets

Serious Allergic Reactions. Stop Taking Dalfampridine Extended-release Tablets And Call Your Doctor Right Away Or Get Emergency Medical Help If You Have: ⮝

shortness of breath or trouble breathing

swelling of your throat or tongue

hives

• Store dalfampridine extended-release tablets at 59 F to 86 F (15 C to 30 C).
• Safely throw away a dalfampridine extended-release tablets that are out of date or no longer needed.

Keepdalfampridine extended-release tabletsand all medicines out of the reach of children.

General Information about the safe and effective use ofdalfampridine extended-release tablets

Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use dalfampridine extended-release tabletsfor a condition for which it was not prescribed. Do not give dalfampridine extended-release tablets to other people, even if they have the same symptoms that you have. It may harm them.

This Medication Guide summarizes the most important information about dalfampridine extended-release tablets. If you would like more information, talk with your doctor. You can ask your pharmacist or doctor for information about dalfampridine extended-release tablets that is written for health professionals.

For more information, call 1-855-839-8195

What are the ingredients indalfampridine extended-release tablets?

Active Ingredient: ⮝

dalfampridine

Inactive Ingredients: ⮝

hypromelloses, magnesium stearate, microcrystalline cellulose, polyethylene glycols, silicon dioxide and titanium dioxide.

This Medication Guide has been approved by the U.S. Food and Drug Administration.

Manufactured By: ⮝

Micro Labs Limited

Goa-403722, INDIA.

Manufactured For: ⮝

Micro Labs USA Inc.

Revised: April2018

Patient Information ⮝

Advise the patient to read the FDA-approved patient labeling (Medication Guide).

Risk of Seizures

Inform patients that dalfampridine can cause seizures, and that they must discontinue use of dalfampridine if they experience a seizure[seeWarnings and Precautions (5.1)].

Dalfampridinedosing

Instruct patients to take dalfampridineexactly as prescribed. Instruct patients not to take a double dose after they miss a dose, as this would increase their risk of seizure. Instruct patients not to take more than 2 tablets in a 24-hour period and to make sure that there is an approximate 12 hour interval between doses[seeDosage and Administration (2.1,2.2)].

Anaphylaxis

Advise patients to discontinue dalfampridine and seek medical care if they develop signs and symptoms of anaphylaxis[seeWarnings and Precautions (5.4)].

Drug Interactions

Instruct patients to notify their healthcare provider prior to starting any new medication, including over-the-counter drugs.

Storage

Advise patients to store dalfampridine extended- release tablets at 25 C (77 F), with excursions permitted to 15 C to 30 C (59 F to 86 F). Advise patients to safely throw away dalfampridine extended- release tablets that is out of date or no longer needed.

1. 1 Indications & Usage
2. 2 Dosage & Administration
3. 3 Dosage Forms & Strengths
4. Highlights Of Prescribing Information
5. Indications And Usage
6. Dosage And Administration
7. Dosage Forms And Strengths
8. Contraindications
9. Warnings And Precautions
10. Adverse Reactions
11. Drug Interactions
12. Use In Specific Populations
13. 1 Indications And Usage
14. 2 Dosage And Administration
15. 3 Dosage Forms And Strengths
16. 4 Contraindications
17. 5 Warnings And Precautions
18. 6 Adverse Reactions
19. 7 Drug Interactions
20. 8 Use In Specific Populations
21. 10 Overdosage
22. 11 Description
23. 12 Clinical Pharmacology
24. 13 Nonclinical Toxicology
25. 14 Clinical Studies
26. 16 How Supplied/storage And Handling
27. Package Label.principal Display Panel

1 Indications & Usage ⮝

Dalfampridine extended-release tablets are indicated as a treatment to improve walking in adult patients with multiple sclerosis (MS). This was demonstrated by an increase in walking speed [see Clinical Studies (14)].

2 Dosage & Administration ⮝

2.1 Dosage Information

The maximum recommended dosage of dalfampridine extended-release tablets is one 10 mg tablet twice daily and should not be exceeded. Take doses approximately 12 hours apart.

There is no evidence of additional benefit at doses greater than 10 mg twice daily. Adverse reactions, including seizures, and discontinuations because of adverse reactions were more frequent at higher doses.

2.2 Administration Instructions

Dalfampridine extended-release tablets can be taken with or without food. Administer tablets whole; do not divide, crush, chew, or dissolve dalfampridine extended-release tablets.

If a dose is missed, patients should not take double or extra doses.

2.3 Renal Monitoring Prior to and During Treatment

Estimated creatinine clearance (CrCl) should be known before initiating treatment with dalfampridine extended-release tablets, and monitored at least annually during treatment with dalfampridine extended-release tablets. CrCl can be estimated using the following equation (multiply by 0.85 for women):

2.4 Dosage in Patients with Renal Impairment

In patients with mild renal impairment (CrCl 51 to 80 mL/min), dalfampridine extended-release tablets plasma levels may approach those seen at a dose of 15 mg twice daily, a dose that is 1.5 times the maximum recommended dose and may be associated with an increased risk of seizures. As mild renal impairment is common after age 50, estimating CrCl is particularly important in these patients. The potential benefits of dalfampridine extended-release tablets should be carefully considered against the risk of seizures in these patients [see Warnings and Precautions (5.2) and Clinical Pharmacology (12.4)].

Dalfampridine extended-release tablets are contraindicated in patients with moderate or severe renal impairment (CrCl 50 mL/min).

3 Dosage Forms & Strengths ⮝

Dalfampridine extended-release tablets are available in 10 mg strength and are white to off-white, round, biconvex, beveled edged, film-coated tablets imprinted with 429 in black ink on one side and plain on the other side.

Highlights Of Prescribing Information ⮝

These highlights do not include all the information needed to use DALFAMPRIDINE EXTENDED-RELEASE TABLETS safely and effectively. See full prescribing information for DALFAMPRIDINE EXTENDED-RELEASE TABLETS.



DALFAMPRIDINE extended-release tablets, for oral use

Initial U.S. Approval: 2010

Indications And Usage ⮝

Dalfampridine extended-release tablet is a potassium channel blocker indicated to improve walking in adult patients with multiple sclerosis (MS). This was demonstrated by an increase in walking speed (1,14).

Dosage And Administration ⮝

• The maximum recommended dosage is 10 mg twice daily (approximately 12 hours apart). There is no evidence of additional benefit with doses greater than 10 mg twice daily. Adverse reactions, including seizures, were more frequent at higher doses. ( 2.1)
• Take with or without food. Administer tablets whole; do not divide, crush, chew, or dissolve ( 2.2)
• Patients should not take double or extra doses if they miss a dose. ( 2.2)
• Estimated creatinine clearance (CrCl) should be known before initiating treatment with dalfampridine. In patients with mild renal impairment (CrCl 51 to 80 mL/min), dalfampridine may reach plasma levels associated with a greater risk of seizures, and the potential benefits of dalfampridine should be carefully considered against the risk of seizures in these patients ( 2.3, 5.2, 8.6)

Dosage Forms And Strengths ⮝

10 mg tablets (3)

Contraindications ⮝

• History of seizure (4)
• Moderate or severe renal impairment (CrCl 50 mL/min) (4)
• History of hypersensitivity to dalfampridine or 4-aminopyridine (4)

Warnings And Precautions ⮝

• Dalfampridine can cause seizures; the risk of seizures increases with increasing dalfampridine doses; discontinue dalfampridine and do not restart if a seizure occurs (5.1)
• Avoid concomitant use with other forms of 4-aminopyridine (4 AP, fampridine), since the active ingredient is the same (5.3)
• Dalfampridine can cause anaphylaxis. Discontinue and do not restart dalfampridine if this occurs (5.4)

Adverse Reactions ⮝

The most common adverse events (incidence 2% and at a rate greater than the placebo rate) for dalfampridine were urinary tract infection, insomnia, dizziness, headache, nausea, asthenia, back pain, balance disorder, multiple sclerosis relapse, paresthesia, nasopharyngitis, constipation, dyspepsia, and pharyngolaryngeal pain (6.1).

To report SUSPECTED ADVERSE REACTIONS, contact Micro Labs USA, Inc. at 1-855-839-8195 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Drug Interactions ⮝

OCT2 Inhibitors: Concomitant use may cause an increased exposure and potential risk of seizures ( 7.1)

Use In Specific Populations ⮝

• Pregnancy: Based on animal data, may cause fetal harm (8.1)
• Nursing Mothers: Discontinue drug or nursing taking into consideration importance of drug to mother (8.3)
• Geriatric use: Because elderly patients are more likely to have decreased renal function, it is particularly important to know the estimated CrCl in these patients before initiating dalfampridine treatment (4, 5.2,8.6)

See 17 for PATIENT COUNSELING INFORMATION and Medication Guide.

Revised: 3/2019

1 Indications And Usage ⮝

Dalfampridine extended-release tablet is indicated as a treatment to improve walking in adult patients with multiple sclerosis (MS). This was demonstrated by an increase in walking speed [see Clinical Studies (14)].

2 Dosage And Administration ⮝

2.1 Dosage Information

The maximum recommended dosage of dalfampridine is one 10 mg tablet twice daily and should not be exceeded. Take doses approximately 12 hours apart.

There is no evidence of additional benefit at doses greater than 10 mg twice daily. Adverse reactions, including seizures, and discontinuations because of adverse reactions were more frequent at higher doses.

2.2 Administration Instructions

Dalfampridine can be taken with or without food. Administer tablets whole; do not divide, crush, chew, or dissolve dalfampridinetablets.

If a dose is missed, patients should not take double or extra doses.

2.3 Renal Monitoring Prior to and During Treatment

Estimated creatinine clearance (CrCl) should be known before initiating treatment with dalfampridine, and monitored at least annually during treatment with dalfampridine. CrCl can be estimated using the following equation (multiply by 0.85 for women):

CrCl = (140 age) weight (kg)

SerumCr (mg / dl) 72

2.4 Dosage in Patients with Renal Impairment

In patients with mild renal impairment (CrCl 51 to 80 mL/min), dalfampridine plasma levels may approach those seen at a dose of 15 mg twice daily, a dose that is 1.5 times the maximum recommended dose and may be associated with an increased risk of seizures. As mild renal impairment is common after age 50, estimating CrCl is particularly important in these patients. The potential benefits of dalfampridine should be carefully considered against the risk of seizures in these patients [see Warnings and Precautions (5.2) and Clinical Pharmacology (12.4)]. Dalfampridine is contraindicated in patients with moderate or severe renal impairment (CrCl 50 mL/min).

3 Dosage Forms And Strengths ⮝

Dalfampridine extended-release tablet is available in a 10 mg strength and is white to off-white colored, oval shaped, biconvex, film coated tablet debossed with C51 on one side and plain on other side. Tablet dimensions are approximately 13 mm (Length) and 8 mm (Width).

4 Contraindications ⮝

The use of dalfampridine is contraindicated in the following conditions:

• History of seizure [see Warnings and Precautions (5.1)]
• Moderate or severe renal impairment (CrCl 50 mL/min) [see Warnings and Precautions (5.2)]
• History of hypersensitivity to dalfampridine or 4-aminopyridine; reactions have included anaphylaxis [see Warnings and Precautions (5.4)]

5 Warnings And Precautions ⮝

5.1 Seizures

Dalfampridine can cause seizures. Increased incidence of seizures has been observed at 20 mg twic e daily (2 times the maximum recommended dosage) in controlled clinical studies of 9 to 14 weeks duration with dalfampridine in patients with MS. In open-label extension trials in MS patients, the incidence of seizures during treatment with dalfampridine 15 mg twice daily (1.7/100PY) was over 4 times higher than the incidence during treatment with 10 mg twice daily (0.4/100PY). In the post-marketing period seizures have been reported. The majority of seizures occurred at the recommended dose and in patients without a history of seizures, and generally within days to weeks of starting therapy.

Dalfampridine has not been evaluated in patients with a history of seizures or with evidence of epileptiform activity on an EEG, as these patients were excluded from clinical trials. The risk of seizures in patients with epileptiform activity on an EEG is unknown, and could be substantially higher than that observed in dalfampridine clinical studies. Permanently discontinue dalfampridinein patients who have a seizure while on treatment. Dalfampridineis contraindicated in patients with a history of seizures [see Contraindications (4)] .

5.2 Renal Impairment

Dalfampridine is eliminated through the kidneys primarily as unchanged drug [see Clinical Pharmacology (12.4)].

Because patients with moderate to severe renal impairment (CrCl 50mL/min) would require a dose lower than 10 mg twice daily and no strength smaller than 10 mg is available, dalfampridine is contraindicated in these patients [see Contraindications (4)] .

In patients with mild renal impairment (CrCl 51 to 80 mL/min), dalfampridine plasma levels may approach those seen at a dose of 15 mg twice daily, a dose that may be associated with an increased risk of seizures [see Warnings and Precautions (5.1)] .

5.3 Concurrent Treatment with Other Forms of 4-Aminopyridine

Avoid concomitant use with other forms of 4-aminopyridine (4-AP, fampridine) since the active ingredient is the same. Instruct patients to discontinue use of any product containing 4 - aminopyridine prior to initiating treatment with dalfampridine in order to reduce the potential for dose-related adverse reactions.

5.4 Anaphylaxis

Dalfampridine can cause anaphylaxis and severe allergic reactions. Signs and symptoms have included respiratory compromise, urticaria, and angioedema of the throat and or tongue. D alfampridine is contraindicated in patients with a history of hypersensitivity to dalfampridine or 4 aminopyridine. Inform patients of the signs and symptoms of anaphylaxis and instruct them to discontinue dalfampridine and seek immediate medical care should these signs and symptoms occur.

6 Adverse Reactions ⮝

The following serious adverse reactions are described in more detail elsewhere in the labeling:

• Seizures [see Warnings and Precautions (5.1)]
• Anaphylaxis [see Warnings and Precautions (5.4)]

6.1 Controlled Clinical Trials Experience

Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice.

In three placebo-controlled clinical trials of up to 14 weeks duration, 4% (15/400) of patients treated with dalfampridine extended-release tablets 10 mg twice daily experienced one or more treatment emergent adverse reactions leading to discontinuation, compared to 2% (5/238) of placebo-treated patients. The treatment emergent adverse reactions leading to discontinuation of at least 2 patients treated with dalfampridine and that led to discontinuation more frequently compared to placebo were headache (dalfampridine 0.5%, placebo 0%), balance disorder (dalfampridine 0.5%, placebo 0%), dizziness (dalfampridine 0.5%, placebo 0%), and confusional state (dalfampridine 0.3%, placebo 0%).

Table 1 lists adverse reactions that occurred in 2% of patients treated with dalfampridine extended-release tablets 10 mg twice daily, and more frequently than in placebo-treated patients, in controlled clinical trials.

Table 1: Adverse Reactions with an Incidence 2% of Dalfampridine-Treated Adult MS Patients and More Frequent with Dalfampridine Compared to Placebo in Controlled Clinical Trials

Adverse Reaction	Placebo (N=238)	Dalfampridine 10 mg twice daily (N=400) (N=400)
Urinary tract infection	8%	12%
Insomnia	4%	9%
Dizziness	4%	7%
Headache	4%	7%
Nausea	3%	7%
Asthenia	4%	7%
Back pain	2%	5%
Balance disorder	1%	5%
Multiple sclerosis relapse	3%	4%
Paresthesia	3%	4%
Nasopharyngitis	2%	4%
Constipation	2%	3%
Dyspepsia	1%	2%
Pharyngolaryngeal pain	1%	2%

Other Adverse Reactions

Dalfampridine has been evaluated in a total of 1,952 subjects, including 917 MS patients. A total of 741 patients have been treated with dalfampridine for over six months, 501 for over one year and 352 for over two years. The experience in open-label clinical trials is consistent with the safety profile observed in the placebo-controlled clinical trials. As in controlled clinical trials, a dose-dependent increase in the incidence of seizures has been observed in open-label clinical trials with dalfampridine in patients with MS as follows: dalfampridine extended-release tablets 10 mg twice daily 0.41 per 100 person-years (95% confidence interval 0.13 to 0.96); dalfampridine 15 mg twice daily 1.7 per 100 person-years (95% confidence interval 0.21 to 6.28).

6.2 Postmarketing Experience

The following adverse event has been identified during post-marketing experience with dalfampridine. Because adverse events 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: vomiting.

7 Drug Interactions ⮝

7.1 OCT2 Inhibitors

Concurrent treatment with OCT2 inhibitors, such as cimetidine, may cause increased exposure to dalfampridine [see Clinical Pharmacology (12.3)] . Elevated levels of dalfampridine increase the risk of seizures [see Warnings and Precautions (5.1, 5.2)]. The potential benefits of taking OCT2 inhibitors concurrently with dalfampridine should be considered against the risk of seizures in these patients.

7.2 Baclofen

No interaction was identified between dalfampridine and baclofen [see Clinical Pharmacology (12.3)].

8 Use In Specific Populations ⮝

8.1 Pregnancy

Pregnancy Category C

There are no adequate and well-controlled studies of dalfampridine in pregnant women. Administration of dalfampridine to animals during pregnancy and lactation resulted in decreased offspring viability and growth at doses similar to the maximum recommended human dose (MRHD) of 20 mg/day. Dalfampridine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

In developmental toxicity studies in rats and rabbits, dalfampridine was administered orally at doses up to 10 and 5 mg/kg/day, respectively, during the period of organogenesis. These doses are approximately 5 times the MRHD on a body surface area (mg/m 2) basis. No evidence of developmental toxicity was found in either species at the highest doses tested, which were maternally toxic. Oral administration of dalfampridine (at doses of 1, 3, and 9 to 6 mg/kg/day; high dose reduced during the second week of dosing) to rats throughout the pregnancy and lactation periods resulted in decreased offspring survival and growth. The no-effect dose for pre- and postnatal developmental toxicity in rats (1 mg/kg) is approximately 0.5 times the MRHD on a mg/m 2 basis.

8.2 Labor and delivery

The effect of dalfampridine on labor and delivery in humans is unknown.

8.3 Nursing mothers

It is not known whether dalfampridine is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from dalfampridine, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

8.4 Pediatric use

Safety and effectiveness of dalfampridine in patients younger than 18 years of age have not been established.

8.5 Geriatric use

Clinical studies of dalfampridine did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently than younger subjects. A population PK analysis showed that dalfampridine clearance modestly decreased with increasing age, but not sufficiently to necessitate a modification of dose with age. Other reported clinical experience has identified no differences in responses between the elderly and younger patients.

Dalfampridine is known to be substantially excreted by the kidneys and the risk of adverse reactions, including seizures, is greater with increasing exposure of dalfampridine. Because elderly patients are more likely to have decreased renal function, it is particularly important to know the estimated creatinine clearance (CrCl) in these patients [see Warnings and Precautions (5.2)].

8.6 Impaired Renal Function

Clearance of dalfampridine is decreased in patients with renal impairment and is significantly correlated with creatinine clearance (CrCl) [see Clinical Pharmacology (12.4)] . Dalfampridine is contraindicated in patients with moderate or severe renal impairment (CrCl 50 mL/min) [see Contraindications (4)]. The risk of seizures in patients with mild renal impairment (CrCl 51 to 80 mL/min) is unknown, but dalfampridine plasma levels in these patients may approach those seen at a dose of 15 mg twice daily, a dose that may be associated with an increased risk of seizures. If unknown, estimated creatinine clearance should be calculated prior to initiating treatment with dalfampridine [see Dosage and Administration(2.3) and Warnings and Precautions (5.2)] .

10 Overdosage ⮝

Three cases of overdose were reported in controlled clinical trials with dalfampridine, involving two MS patients. The first patient took six times the currently recommended dose (60 mg) and was taken to the emergency room with altered mental state. The second patient took 40 mg doses on two separate occasions. In the first instance, she experienced a complex partial seizure and, in the second instance, a period of confusion. Both patients recovered by the following day without sequelae.

Several cases of overdose are found in the scientific literature in which various formulations of dalfampridine were used, resulting in numerous adverse events including seizure, confusion, tremulousness, diaphoresis, and amnesia. In some instances, patients developed status epilepticus, requiring intensive supportive care and were responsive to standard therapy for seizures. In one published case report, an MS patient who ingested 300 mg of 4-aminopyridine (dalfampridine) developed a condition that resembled limbic encephalitis. This patient developed weakness, reduced awareness, memory loss, hypophonic speech, and temporal lobe hyperintensities on MRI. The patient s speech and language and ambulation improved over time, and an MRI at 4 months after the overdose no longer showed signal abnormalities. At one year, the patient continued to have difficulty with short term memory and learning new tasks.

11 Description ⮝

Dalfampridine extended-release tablet is a potassium channel blocker, available in a 10 mg tablet strength. Each tablet contains 10 mg dalfampridine, formulated as an extended-release tablet for twice-daily oral administration. Dalfampridine is also known by its chemical name, 4-aminopyridine, with the following structure:

Dalfampridine extended-release tablets are available in a 10 mg strength and are white to off-white colored oval shaped biconvex film coated tablet debossed with C51 on one side and plain on other side. Tablet dimensions are approximately 13 mm (Length) and 8 mm (Width). Inactive ingredients consist of hypromelloses, magnesium stearate, microcrystalline cellulose, polyethylene glycols, silicon dioxide and titanium dioxide.

Dalfampridine is a fine white powder with a molecular weight of 94.1, CAS 504-24-5, and a molecular formula of C 5H 6N 2. At ambient conditions, dalfampridine is soluble in water, methanol, acetone, tetrahydrofuran, isopropanol, acetonitrile, N,N-dimethylformamide, dimethylsulfoxide, and ethanol.

12 Clinical Pharmacology ⮝

12.1 Mechanism of action

The mechanism by which dalfampridine exerts its therapeutic effect has not been fully elucidated. Dalfampridine is a broad spectrum potassium channel blocker. In animal studies, dalfampridine has been shown to increase conduction of action potentials in demyelinated axons through inhibition of potassium channels.

12.2 Pharmacodynamics

Dalfampridine does not prolong the QTc interval and does not have a clinically important effect on QRS duration.

12.3 Pharmacokinetics

Absorption and Distribution:

Orally administered dalfampridine is rapidly and completely absorbed from the gastrointestinal tract. Absolute bioavailability of dalfampridine extended-release e tablets has not been assessed, but relative bioavailability is 96% when compared to an aqueous oral solution. The extended-release tablet delays absorption of dalfampridine relative to the solution formulation, giving a slower rise to a lower peak concentration (C max), with no effect on the extent of absorption (AUC). Single dalfampridine extended-release tablet 10 mg doses administered to healthy volunteers in a fasted state gave peak concentrations ranging from 17.3 ng/mL to 21.6 ng/mL occurring 3 to 4 hours post- administration (T max). In comparison, C max with the same 10 mg dose of dalfampridine in an oral solution was 42.7 ng/mL and occurred approximately 1.3 hours after dosing. Exposure increased proportionally with dose.

Dalfampridine is largely unbound to plasma proteins (97 to 99%). The apparent volume of distribution is 2.6 L/kg.

There is no apparent difference in pharmacokinetic parameter values following administration of dalfampridine extended-release tablets to either healthy volunteers or patients with MS.

When dalfampridine is taken with food, there is a slight increase in C max (12 to 17%) and a slight decrease in AUC (4 to 7%). These changes in exposure are not clinically significant, and therefore the drug may be taken with or without food [see Dosage and Administration (2.2)].

Metabolism and Elimination:

Dalfampridine and metabolites elimination is nearly complete after 24 hours, with 95.9% of the dose recovered in urine and 0.5% recovered in feces. Most of the excreted radioactivity in urine was parent drug (90.3%). Two metabolites were identified: 3-hydroxy-4-aminopyridine (4.3%) and 3-hydroxy-4-aminopyridine sulfate (2.6%). These metabolites have been shown to have no pharmacologic activity on potassium channels.

The apparent elimination half-life of dalfampridine following administration of the extended-release tablet formulation of dalfampridine is 5.2 to 6.5 hours. The plasma half-life of the sulfate conjugate is approximately 7.6 hours and the half-life of 3-hydroxy-4-aminopyridine could not be calculated because concentrations for most subjects were close to or below the limit of quantitation.

In vitro studies with human liver microsomes indicate that CYP2E1 was the major enzyme responsible for the 3-hydroxylation of dalfampridine. The identity of the CYP enzymes suspected of playing a minor role in the 3-hydroxylation of dalfampridine could not be established unequivocally.

Specific Populations

Pediatric

The safety and effectiveness of dalfampridine in patients younger than 18 years of age have not been established.

Geriatric

A population pharmacokinetic analysis showed that dalfampridine clearance modestly decreased with increasing age, but not sufficiently to necessitate a modification of dose.

Gender

A population pharmacokinetic analysis suggested that female patients would be expected to have higher maximum dalfampridine plasma concentration than male patients. The magnitude of these differences is small and does not necessitate any dose modification.

Renal Impairment[see Contraindications (4)and Warnings and Precautions (5.2)].

The pharmacokinetics of dalfampridine was studied in 9 male and 11 female subjects with varying degrees of renal function. Elimination of the drug is significantly correlated with the creatinine clearance. Total body clearance of dalfampridine was reduced by about 45 % in patients with mild renal impairment (CrCl 51 to 80 mL/min), by about 50% in patients with moderate renal impairment (CrCl = 30 to 50 mL/min), and by about 75% in patients with severe renal impairment (CrCl <30 mL/min). The terminal half-life of dalfampridine is about 3.3 times longer in patients with severe renal impairment but is not prolonged in patients with mild or moderate renal impairment.

Hepatic Impairment

The pharmacokinetics of dalfampridine in hepatically impaired subjects has not been studied. Since dalfampridine is primarily excreted unchanged in the urine, hepatic impairment is not expected to significantly affect dalfampridine pharmacokinetics or recommended dosing.

Race

There were too few non-Caucasians in the patient population to evaluate the effect of race.

Drug Interactions

Effects of Co-administered Drugs on Dalfampridine

Interferon

Dalfampridine kinetics were not affected by co-administration of subcutaneous injections of 8 million units interferon beta-1b.

Baclofen

Based on a population analysis, dalfampridine kinetics were not affected by baclofen.

Cimetidine

In a single-dose clinical study, 23 healthy volunteers took the OCT2 inhibitor cimetidine 400 mg every 6 hours concurrently with dalfampridine 10 mg single dose. The test-reference ratio for AUC0 to was 125% (90% confidence interval: 121% to 130%) due to a reduction in the clearance of dalfampridine [see Drug Interactions (7.1)].

Effects of Dalfampridine on Co-administered Drugs

In vitro data with human liver microsomes showed that dalfampridine was not a direct or time-dependent inhibitor of CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, or CYP3A4/5. Dalfampridine is not likely to affect the pharmacokinetics of drugs that are substrates of these enzymes.

Other in vitro studies with cultured human hepatocytes with 0.025 M, 0.25 M, 2.5 M, and 25 Mdalfampridine had little or no effect on CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2E1, or CYP3A4/5 enzyme activities. Consequently, the potential for dalfampridine to induce human hepatocytes at therapeutic concentrations is remote.

In vitro, dalfampridine is not a substrate or an inhibitor for the p-glycoprotein transporter. The pharmacokinetics of dalfampridine are unlikely to be affected by drugs that inhibit the p glycoprotein transporter, and dalfampridine is not likely to affect the pharmacokinetics of drugs that are substrates of the p-glycoprotein transporter.

13 Nonclinical Toxicology ⮝

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis: Two year dietary carcinogenicity studies of dalfampridine were conducted in mice and rats. In mice, the doses tested (approximately 2, 12.5, and 80 mg/kg/day) were associated with plasma exposures (AUC) up to 11 times the plasma AUC in humans at the maximum recommended human dose (MRHD) of 20 mg/day. There was no evidence of drug- related carcinogenicity.

In rats, the doses tested (approximately 2, 6, and 18 mg/kg/day) were approximately 1, 3, and 9 times the MRHD on a body surface area (mg/m 2) basis. There was a significant increase in uterine polyps at the highest dose tested.

Mutagenesis: Dalfampridine was negative in in vitro (bacterial reverse mutation, mouse lymphoma tk, chromosomal aberration) and in vivo (mouse bone marrow, rat erythrocyte micronucleus) genetic toxicology assays.

Impairment of Fertility: Oral administration of dalfampridine (doses of 1, 3, and 9 mg/kg/day) to male and female rats prior to and throughout mating, and continuing in females up to day 13 of gestation or day 21 of lactation resulted in no adverse effects on fertility. Reduced offspring viability and body weight were observed at 9 mg/kg/day. The mid dose (a no-effect dose) was similar to the MRHD on a mg/m 2 basis.

14 Clinical Studies ⮝

The effectiveness of dalfampridine in improving walking in patients with multiple sclerosis was evaluated in two adequate and well controlled trials involving 540 patients. Patients in these two clinical trials had a mean disease duration of 13 years and a mean Kurtzke Expanded Disability Status Scale (EDSS) score of 6.

Trial 1 was a randomized, placebo-controlled, parallel group, 21-week study (one week post screening, two-week, single-blind placebo run-in, 14-week double-blind treatment, and 4-week no treatment follow-up) in 301 patients with multiple sclerosis at 33 centers in the U.S. and Canada: 229 patients assigned to dalfampridine extended-release tablets 10 mg twice daily and 72 patients assigned to placebo. A total of 283 patients (212 dalfampridine extended-release tablets and 71 placebo) completed all study visits. Patient inclusion criteria included the ability to walk 25 feet in 8 to 45 seconds. Patient exclusion criteria included a history of seizures or evidence of epileptiform activity on a screening EEG, and onset of an MS exacerbation within 60 days.

Trial 2 was a randomized, placebo-controlled, parallel group, 14-week study (one week post- screening, two weeks of single-blind, placebo run-in, nine weeks of double-blind treatment, and two weeks of no-treatment follow-up) in 239 patients with multiple sclerosis at 39 centers in the U.S. and Canada: 120 patients assigned to 10 mg twice daily and 119 assigned to placebo. A total of 227 patients (113 dalfampridine extended-release tablets and 114 placebo) completed all study visits. The patient inclusion and exclusion criteria used in Trial 1 were employed in Trial 2, and in addition patients with severe renal impairment were also excluded.

The primary measure of efficacy in both trials was walking speed (in feet per second) as measured by the Timed 25-foot Walk (T25FW), using a responder analysis. A responder was defined as a patient who showed faster walking speed for at least three visits out of a possible four during the double-blind period than the maximum value achieved in the five non-double blind no treatment visits (four before the double-blind period and one after).

A significantly greater proportion of patients taking dalfampridine extended-release tablets 10 mg twice daily were responders, compared to patients taking placebo, as measured by the T25FW (Trial 1: 34.8% vs. 8.3%; Trial 2: 42.9% vs. 9.3%). The increased response rate in the dalfampridine group was observed across all four major types of MS disease course.

During the double-blind treatment period, a significantly greater proportion of patients taking dalfampridine extended-release tablets 10 mg twice daily had increases in walking speed of at least 10%, 20%, or 30% from baseline, compared to placebo (Figure 1 and Figure 2).

Figure 1: Average walking speed change (%) from baseline during the double-blind phase of Trial 1

P values provided at each threshold comparing dalfampridine extended-release tablets to placebo.

Figure 2: Average walking speed change (%) from baseline during the double-blind phase of Trial 2

P values provided at each threshold comparing dalfampridine extended-release tablets to placebo.

In Trial 1 and Trial 2, consistent improvements in walking speed were shown to be associated with improvements on a patient self-assessment of ambulatory disability, the 12-item Multiple Sclerosis Walking Scale (MSWS-12), for both drug and placebo treated patients. However, a drug-placebo difference was not established for that outcome measure.

The majority of patients in these trials (63%) were using immunomodulatory drugs (interferons, glatiramer acetate, or natalizumab), but the magnitude of improvement in walking ability was independent of concomitant treatment with these drugs. No differences in effectiveness based on degree of impairment, age, gender, or body mass index were detected. There were too few non-Caucasians in the patient population to evaluate the effect of race.

16 How Supplied/storage And Handling ⮝

Dalfampridine extended-release tablets, 10 mg are film-coated,white to off-white colored oval shaped, biconvex, film coated tablet debossed with C51 on one side and plain on other side. Tablet dimensions are approximately 13 mm (Length) and 8 mm (Width).

Bottles of 60 NDC 42571-275-60

Bottles of 500 NDC 42571-275-05

Bottles of 1,000 NDC 42571-275-10

Store at 25 C (77 F). Excursions permitted 15 C to 30 C (59 F to 86 F ).

Package Label.principal Display Panel ⮝

NDC 42571-275-60 Rx only

Dalfampridine
Extended-Release
Tablets

10 mg

PHARMACIST: Dispense the
accompanying Medication Guide to
each patient
60 Tablets

MICRO LABS

DALFAMPRIDINE dalfampridine tablet, extended release

Product Information Product Type HUMAN PRESCRIPTION DRUG Item Code (Source) NDC:42571-275 Route of Administration ORAL

Active Ingredient/Active Moiety Ingredient Name Basis of Strength Strength DALFAMPRIDINE (UNII: BH3B64OKL9) (DALFAMPRIDINE - UNII:BH3B64OKL9) DALFAMPRIDINE 10 mg

Inactive Ingredients Ingredient Name Strength HYPROMELLOSES (UNII: 3NXW29V3WO) MAGNESIUM STEARATE (UNII: 70097M6I30) MICROCRYSTALLINE CELLULOSE (UNII: OP1R32D61U) POLYETHYLENE GLYCOL, UNSPECIFIED (UNII: 3WJQ0SDW1A) SILICON DIOXIDE (UNII: ETJ7Z6XBU4) TITANIUM DIOXIDE (UNII: 15FIX9V2JP)

Product Characteristics Color white (White to-off whie) Score no score Shape OVAL Size 13mm Flavor Imprint Code C51 Contains

Packaging # Item Code Package Description Marketing Start Date Marketing End Date 1 NDC:42571-275-60 60 in 1 BOTTLE; Type 0: Not a Combination Product 03/21/2019 2 NDC:42571-275-05 500 in 1 BOTTLE; Type 0: Not a Combination Product 03/21/2019 3 NDC:42571-275-10 1000 in 1 BOTTLE; Type 0: Not a Combination Product 03/21/2019

Marketing Information Marketing Category Application Number or Monograph Citation Marketing Start Date Marketing End Date ANDA ANDA210158 03/21/2019

Labeler - Micro Labs Limited (862174955)

Establishment
Name	Address	ID/FEI	Business Operations
Micro Labs Limited		915793658	analysis(42571-275) , label(42571-275) , manufacture(42571-275) , pack(42571-275)

Revised: 3/2019 Document Id: 83d234fd-bdfa-b646-e053-2a91aa0a3b12 34391-3 Set id: 302c8270-4711-4ca4-bee8-be0738fbe094 Version: 4 Effective Time: 20190311 Micro Labs Limited