Etripamil

CARDAMYST is indicated for the conversion of acute symptomatic episodes of paroxysmal supraventricular tachycardia (PSVT) to sinus rhythm in adults. CARDAMYST is a calcium channel blocker indicated for the conversion of acute symptomatic episodes of paroxysmal supraventricular tachycardia (PSVT) to sinus rhythm in adults ( 1 ).

Nasal Spray: Clear colorless to yellow solution. 70 mg of etripamil per device. Nasal spray: 70 mg etripamil per device ( 3 ).

CARDAMYST is contraindicated in patients with: Hypersensitivity to CARDAMYST or any of its components. Heart failure – New York Heart Association (NYHA) Class II to IV. Wolff-Parkinson-White (WPW), Lown-Ganong-Levine (LGL) syndromes, or manifest pre-excitation (delta wave) on a 12-lead electrocardiogram (ECG). Sick sinus syndrome without a permanent pacemaker. Second degree atrioventricular (AV) Mobitz 2 block or higher degree of AV block. Hypersensitivity to CARDAMYST or any of its components ( 4 ). Heart failure – New York Heart Association (NYHA) Class II to IV ( 4 ). Wolff-Parkinson-White (WPW), Lown-Ganong-Levine (LGL) syndromes, or manifest pre-excitation (delta wave) on a 12-lead ECG ( 4 ). Sick sinus syndrome (except in patients with a permanent pacemaker) ( 4 ) Second degree atrioventricular (AV) Mobitz 2 block or higher degree of AV block ( 4 )

Syncope: May cause dizziness and/or syncope, especially in patients with a history of syncope. Administer in a sitting position ( 5.1 ).

5.1 Syncope Related to Hemodynamic Effects Because of effects on blood pressure, heart rate, and cardiac conduction, CARDAMYST may cause dizziness and/or syncope, especially in patients with a history of syncope and high-grade AV block or sinus node dysfunction, or those with a history of syncope during an episode of PSVT. In clinical trials, a small percentage of patients (0.4%) experienced clinically significant hypotension during test dosing prior to randomization, which precluded further participation in the study. Patients with a history of hypotensive episodes or those at increased risk for hemodynamic instability should be monitored appropriately when initiating CARDAMYST. If syncope occurs, patients should be placed in the recumbent position and treated supportively. Patients should be cautioned about these possible adverse effects and advised to administer CARDAMYST in a sitting position, and in a location where the risk of fall is minimal.

The following clinically significant adverse reactions are described elsewhere in the labeling: Risk of syncope [see Warnings and Precautions ( 5.1 )] Most common adverse reactions (incidence > 5%) are nasal discomfort, nasal congestion, rhinorrhea, throat irritation, and epistaxis ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Milestone Pharmaceuticals USA, INC. at toll-free phone 1-877-207-4764 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. The safety of CARDAMYST was evaluated using pooled data from double-blind, randomized, placebo-controlled trials including NODE-1, NODE-301 Part 1, RAPID, and RAPID Extension. A total of 321 patients were treated with CARDAMYST in randomized controlled studies. In the RAPID and RAPID Extension studies, in which patients had the option of self-administering a second dose of CARDAMYST for a perceived episode of PSVT, the majority of patients (65%) self-administered a second dose of CARDAMYST (2x70mg). In NODE-301 Part 1, RAPID, and RAPID Extension, to assess tolerability, a test dose(s) was given prior to randomization. A small percentage of patients failed the test dose due to hypotension (0.4%) [see Warnings and Precautions ( 5.1 )]. The majority of treatment-related adverse reactions reported in clinical studies with CARDAMYST have been related to local reactions to, at, or near the nasal administration site, including the nose, throat, and eyes. These local reactions included nasal discomfort, nasal congestion, throat irritation, oropharyngeal pain, lacrimation, rhinorrhea, bleeding from the nose, upper-airway cough syndrome, and sneezing. Table 1: Most frequent (≥5.0%) Adverse Reactions 1 Observed in Randomized Controlled Studies 1) Adverse reactions that occurred within 24 hours of study drug administration (TEAE24h) for perceived PSVT in the double-blind, placebo-controlled studies, NODE-1, NODE-301 Part 1, RAPID and RAPID Extension that had an overall incidence of 5% or greater and where the incidence is at least 1% greater than the placebo group. 2) 2×70 mg: first administration of etripamil 70 mg followed by a second dose of etripamil 70 mg 10 minutes later if symptoms persisted. Placebo N=223 % CARDAMYST 70 mg N=235 % CARDAMYST 2×70 mg 2 N=86 % Nasal Discomfort 6 28 23 Nasal Congestion 1 14 12 Rhinorrhea 2 12 10 Throat Irritation 1 7 6 Epistaxis 1 6 7

Lactation: A lactating woman should pump and discard breastmilk for 12 hours after CARDAMYST administration ( 8.2 ).

8.1 Pregnancy Risk Summary There are no available data on the use of CARDAMYST during pregnancy to inform a drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes. Reproductive studies conducted with intravenous administration of etripamil in pregnant rats and rabbits during organogenesis did not show any evidence of fetal harm or malformations in rats at exposures up to approximately 3x the maximum concentration (C max ) and 0.4x the AUC at the maximum recommended human dose (MRHD) and in rabbits at exposures approximately equivalent to the C max and 10x the AUC at the MRHD, at which maternal toxicities were observed (see Data ). The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2%-4% and 15%-20%, respectively. Data Animal Data In pregnant rats, intravenous administration of etripamil throughout the period of organogenesis did not result in any adverse effects on embryofetal development at doses up to 0.375 mg/kg/day, approximately 3x the C max and 0.4x the AUC at the MRHD. In pregnant rabbits, intravenous administration of etripamil throughout the period of organogenesis did not result in embryofetal abnormalities at doses up to 0.1 mg/kg/day, approximately equivalent to the C max and 10x the AUC at the MRHD. Abortion in one animal was noted at the high dose of 0.1 mg/kg/day, a dose that caused maternal toxicity. In the pre- and post-natal toxicity study in rats, intravenous administration of etripamil from gestation day 7 through the lactation period (post-partum day 20), did not show any adverse effects on pre- and postnatal development at doses up to 0.374 mg/kg/day, approximately 3x the C max and 0.4x the AUC at the MRHD. Post-implantation loss was noted at 0.374 mg/kg/day, a dose that also caused significant maternal toxicity, including mortality, transient adverse clinical signs, and body weight reduction.

8.2 Lactation Risk Summary There are no data on the presence of etripamil in human milk or animal milk. However, the structurally related compound, verapamil, is known to be present in human milk. There are no data on the effects of etripamil on the breastfed infant or on milk production. Because the presence of etripamil in breastmilk has not been characterized, and there is a potential for adverse reactions in the breastfed infant including hypotension and bradycardia, lactating women should interrupt breastfeeding and pump and discard milk for 12 hours (approximately 5 terminal half-lives) after treatment with CARDAMYST.

8.4 Pediatric Use The safety and effectiveness of CARDAMYST have not been established in the pediatric population. Etripamil is structurally similar to another drug in the same pharmacologic class that has been associated with a high risk of potentially non-reversible electromechanical dissociation or cardiovascular collapse in pediatric patients less than 1 year of age, including neonates.

8.5 Geriatric Use Of the total number of patients in clinical trials of CARDAMYST, 41% (681/1662) were 60 years of age and over, and 14% (238/1662) were 70 years of age and over. No meaningful differences in safety or effectiveness were observed between these patients and younger groups.

Etripamil is an L-type calcium influx inhibitor (slow channel blocker or calcium ion antagonist). Etripamil exerts its pharmacologic effect by modulating the influx of ionic calcium across the cell membrane of the AV nodal cells as well as arterial smooth muscles and contractile myocardial cells. By interrupting reentry at the AV node, etripamil can restore sinus rhythm in patients with PSVT.