The investigational intranasal L-type calcium channel blocker etripamil continues to be well tolerated and effective for self-treating recurrent episodes of paroxysmal supraventricular tachycardia (PSVT), results of a new open-label extension study show.
Atripamil, order brand cialis no prescription canada administered as a 70-mg nasal spray, was investigated in the phase 3 NODE-301 study. NODE-302, an open-label extension of that study, enrolled 105 patients (mean age, 58 years). Almost 60% of the patients were women; 82% were White patients. The participants self-treated episodes of perceived PSVT with etripamil for up to 11 episodes.
The main outcome was safety; efficacy outcomes included time to conversion of PSVT to sinus rhythm (SR) after etripamil treatment, as adjudicated by cardiac electrophysiologists who also adjudicated the presence of an atrioventricular nodal-dependent PSVT and termination due to vagal maneuver if PSVT was present.
In the extension study, 235 episodes were treated with etripamil; 188 episodes were adjudicated as positive and 33 as negative; 14 could not be adjudicated because of missing ECG data.
Among the 105 patients who self-administered etripamil for a perceived PSVT event, 87.6% had positively adjudicated PSVT episodes (efficacy population); most patients (72.4%) had one (49.5%) or two (22.9%) episodes that were treated with etripamil, but 27.6% had three or more episodes, including two patients who self-administered etripamil for a total of 11 perceived episodes.
In the safety population (105 patients), 63.8% reported one or more adverse events (AEs), and 42.9% reported one or more treatment-emergent AEs (TEAEs), defined as an AE that occurs within 24 hours of taking a study dose. The most common TEAEs were nasal discomfort (14.3%), nasal congestion (14.3%), and rhinorrhea (12.4%); TEAEs were generally mild or moderate and transient. There were no serious AEs or study withdrawals related to the drug.
There were no reported cases of syncope or hypotension, and ECG recordings revealed no cases of atrioventricular block, bradycardia, or conversion pauses after etripamil administration.
Overall, 60.2% of positively adjudicated cases converted to SR by 30 minutes. The median time to conversion was 15.5 minutes (the rate of conversion at 60 minutes was 75.1%).
The results “demonstrate the consistent safety of etripamil 70-mg nasal spray, self-administered for symptomatic PSVT treatment without medical supervision,” the authors conclude. The medication has a rapid onset of action, and its use could reduce trips to the emergency department to treat vagal maneuver–resistant PSVT episodes, they add.
The study was conducted by James E. Ip, MD, Weill Cornell Medicine, New York–Presbyterian Hospital, New York City, and colleagues. It was published online September 27, 2023, in the Journal of the American Heart Association.
The study was open label, and there was no placebo control. Patients who had a negative experience with the drug in the phase 3 study may have been less likely to enroll in the open-label phase. Patients could use only a single dose of etripamil 70-mg for each PSVT episode, although response to etripamil is likely dose dependent. Patients had access to instructions and a coach, but the study design did not specify when etripamil had to be taken after PSVT initiation, and unobserved patient behaviors could have influenced the rate and time to PSVT conversion.
The study was funded by Milestone Pharmaceuticals, Quebec, Canada. Ip serves on the steering committee for Milestone Pharmaceuticals.
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