A Thorough QT Study to Evaluate the Effects of Supratherapeutic Doses of Ledipasvir on the QTc Interval in Healthy Subjects

This study evaluated the effect of supratherapeutic exposure of the anti-HCV drug ledipasvir on the QTc interval in healthy subjects. Sixty healthy volunteers were randomized to receive twice-daily blinded ledipasvir (120 mg) or placebo, administered for 10 days each, or single doses of open-label moxifloxacin (400 mg). Serial plasma samples for ledipasvir concentration analysis were collected after each treatment. Triplicate time-matched electrocardiograms were collected at baseline and after each treatment. Change from baseline in the QTc for ledipasvir or moxifloxacin versus placebo was determined using several correction formulas (primary: QTcF [Fridericia's]; secondary: QTcN [population] and QTcI [individual]). Pharmacokinetics and exposure-QTc relationships were evaluated. Ledipasvir AUC0-24 and Cmax achieved approximately 3.7-fold and 4.2-fold, respectively, above exposures observed following administration of ledipasvir/sofosbuvir (90/400 mg) to HCV-infected patients. There was a lack of effect of supratherapeutic ledipasvir on QTc intervals using all correction methods (upper bound of the 2-sided 90%CIs for the mean difference in time-matched baseline-corrected QTc between ledipasvir versus placebo 5 milliseconds, thereby establishing assay sensitivity. Categorical analyses did not demonstrate clinically relevant effects of ledipasvir on QTc intervals or other electrocardiogram parameters. No relationships between ledipasvir plasma concentration and QTc interval were observed. Ledipasvir does not prolong QTc interval. Based on these results and a previous TQT evaluation for sofosbuvir, the fixed-dose combination regimen of ledipasvir/sofosbuvir is not expected to prolong the QTc interval.