Efficacy and Safety of Intranasal MSP-2017 (Etripamil) for the Conversion of PSVT to Sinus Rhythm

Inclusion Criteria

• Male or female, aged 18 years and older at Screening
• Has a history of PSVT
• Is scheduled for an electrophysiology study and catheter ablation
• Has provided written informed consent
• Agrees to use a medically accepted form of contraception or abstinence to prevent pregnancy. Males must agree to use an acceptable form of contraception or abstinence from the time of study drug administration through the Follow-up Visit. Females must agree to use an acceptable form of contraception or abstinence from Screening until 30 days following study drug administration. Post-menopausal female subjects must be amenorrheic for ≥ 12 months prior to Screening or ≥ 6 weeks post-surgical bilateral oophorectomy (with or without hysterectomy) prior to Screening, if they do not wish to use an acceptable form of contraception or abstinence. Acceptable forms of contraception include: A condom and an intrauterine device; A condom and hormonal contraception; A condom and a diaphragm; Sterilization of the subject or the subject's partner(s) (sterilization procedure must have been performed 3 or more months prior); Hysterectomy of the subject or the subject's partner(s)
• If a female of childbearing potential: Has a negative serum pregnancy test result at Screening (Screening must occur ≥7 days prior to randomization [ie, on or before Day -7]) and at the Treatment Visit (pre-PSVT induction); Has had a menstrual period within 28 days of the Treatment Visit.

Exclusion Criteria

• Has a history of serious allergic reaction to verapamil (especially when administered intravenously) including rash, itching or swelling (especially of the face, tongue, or throat), severe dizziness, or trouble breathing
• Is currently participating in another drug or device study, or has received an investigational drug or device within 30 days of Screening
• Has evidence of clinically significant cardiovascular, endocrine, gastrointestinal, hematologic, hepatic, immunologic, neurologic, oncologic, pulmonary, psychiatric, or renal disease or any other condition which, in the opinion of the Investigator, would jeopardize the safety of the subject or impact the validity of study results
• Is a female who is breast feeding, pregnant, or planning to become pregnant during the study period
• Has evidence of any clinically significant acute or chronic condition of the nasal cavity (e.g., rhinitis or deviated septum) which could interfere with IN administration of the study drug in either or both nasal cavities
• Has any of the following at screening or at the Treatment Visit: Systolic blood pressure 455 milliseconds at Screening or at the Treatment Visit
• Has a history or evidence of familial long QT syndrome, torsades de pointes, ventricular fibrillation, sustained ventricular tachycardia, Brugada syndrome, or sudden cardiac death
• Has evidence of recurrent or chronic atrial tachycardia, atrial flutter, or atrial fibrillation; that could interfere with the current investigation; or
• Has a history or evidence of congestive heart failure (except New York Heart Association Class I) or pulmonary edema

In addition, randomized subjects who meet any of the following criteria at the Treatment Visit (Day 1) prior to study drug administration, will be excluded from participation in the study:

• PSVT cannot be induced or the mechanism of PSVT is neither Atrioventricular reentrant tachycardia (AVRT) nor Atrioventricular nodal reentry tachycardia (AVNRT)
• It is not possible to sustain an episode of PSVT for 5 minutes
• The subject requires a continuous sedative (e.g., propofol), continuous analgesic, or inhaled anesthetic at any point until time 30. Minimally necessary dose(s) of benzodiazepine(s) (e.g., midazolam) and/or narcotic(s) (e.g., fentanyl) (given via single or multiple administration[s]) may be used at the Investigator's discretion. The identity(-ies) and actual administered dose(s) of any benzodiazepine(s) and/or narcotic(s) should be recorded in the