No QTc Prolongation with Semaglutide: A Thorough QT Study in Healthy Subjects

Semaglutide is a glucagon-like peptide-1 (GLP-1) analog approved for the once-weekly treatment of type 2 diabetes. The objective of this 16-week, double-blind, single-center thorough QT study was to confirm that semaglutide treatment does not prolong cardiac repolarization versus placebo. Prolongation of the QT interval is a biomarker for ventricular tachyarrhythmia.

In a parallel design, 168 healthy subjects were randomized to the treatment or placebo arms, of whom 166 were treated with subcutaneous semaglutide (N = 83; escalated to a supratherapeutic dose of 1.5 mg) or placebo (N = 83). The subjects (60% males) had a mean age of 38.2 years and body mass index of 25.1 kg/m². To assess QT assay sensitivity, subjects in the placebo group received a single 400 mg moxifloxacin dose as positive control, and placebo in a crossover fashion. The primary endpoint was the time-matched change from baseline in QT interval corrected individually for heart rate (ΔQTcI), calculated from 11 electrocardiogram recordings from 0 to 48 h after the last 1.5 mg dose. Similar assessments were made for the therapeutic 0.5 and 1.0 mg semaglutide dose levels.

No QTcI prolongation occurred with any semaglutide dose; the upper limits of two-sided 90% confidence intervals of the placebo-subtracted ΔQTcI were < 10 ms at all doses and time points. Exposure-response analysis showed no dependence of QTcI on semaglutide concentration. QT assay sensitivity was confirmed. The semaglutide safety profile was similar to that of other GLP-1 receptor agonists.

Based on investigations of QT/QTc, no concern with regard to ventricular arrhythmias was raised as semaglutide did not prolong the cardiac repolarization duration in healthy subjects.

ClinicalTrials.gov identifier: NCT 02064348.

Novo Nordisk.