The myeloperoxidase inhibitor mitiperstat (AZD4831) does not prolong the QT interval at expected therapeutic doses

Mitiperstat is a myeloperoxidase inhibitor in clinical development for treatment of patients with heart failure and preserved or mildly reduced ejection fraction, non-alcoholic steatohepatits and chronic obstructive pulmonary disease. We aimed to assess the risk of QT-interval prolongation with mitiperstat using concentration-QT (C-QT) modeling. Healthy male volunteers were randomized to receive single oral doses of mitiperstat 5, 15, 45, 135, or 405 mg (n = 6 per dose) or matching placebo (n = 10) in a phase 1 study (NCT02712372). Time-matched pharmacokinetic and digital electrocardiogram data were collected at the baseline (pre-dose) and at 11 time-points up to 48 h post-dose. C-QT analysis was prespecified as an exploratory objective. The prespecified linear mixed effects model used baseline-adjusted QT interval corrected for the heart rate by Fridericia's formula (ΔQTcF) as a dependent variable and plasma mitiperstat concentration as an independent variable. Initial exploratory analyses indicated that all model assumptions were met (no effect on heart rate; appropriate use of QTcF; no hysteresis; linear concentration-response relationship). Model-predicted mean baseline-corrected and placebo-adjusted ΔΔQTcF was +0.73 ms (90% confidence interval [CI]: -1.73, +3.19) at the highest anticipated clinical exposure (0.093 μmol/L) during treatment with mitiperstat 5 mg once daily. The upper 90% CI was below the established threshold of regulatory concern. The 16-fold margin to the highest observed exposure was high enough to mean that a positive control was not needed. Mitiperstat is not associated with risk of QT-interval prolongation at expected therapeutic concentrations.