AZD8233 antisense oligonucleotide targeting PCSK9 does not prolong QT interval.

Aims: AZD8233 is a proprotein convertase subtilisin/kexin type 9 (PCSK9) antisense oligonucleotide under development for treatment of hypercholesterolaemia. A prespecified concentration-QT analysis was performed based on data from a single ascending dose study that was prospectively designed to act as a TQT study substitute.

Methods: Subcutaneous single doses ranging from 4 to 120 mg were evaluated in 73 adult healthy male subjects. Time-matched 12-lead digital ECG and plasma concentrations (n = 15) were measured at baseline and up to 48 hours after dose in each subject. The analysis was performed using a linear mixed effect model, where change from baseline QTc (ΔQTc) was a dependent variable and time-matched AZD8233 concentration was an independent variable.

Results: The high clinical exposure scenario was defined as 1.7-fold the expected Cmax following an assumed therapeutic dose of 60 mg, which corresponds to AZD8233 plasma concentration of 1.39 μg/mL. Estimated placebo-corrected and baseline-adjusted QTcF interval (ΔΔQTcF) at this concentration was -2.2 ms (90% CI: -4.11, -0.28). Furthermore, the upper 90% ΔΔQTcF confidence interval was estimated to be below 10 ms at all observed concentrations.

Conclusion: As the effect on ΔΔQTcF is below the threshold for regulatory concern (10 ms), it can be concluded that AZD8233 does not induce QTcF prolongation at the high clinical exposure scenario.