Concentration-QTc analysis of soticlestat in healthy adults: An alternative to a thorough QT study

This study aimed to examine the cardiac and overall safety and pharmacokinetic (PK) profiles of soticlestat (TAK-935), an oral, first-in-class selective cholesterol 24-hydroxylase inhibitor.

Data came from a randomised, phase 1 study of soticlestat in 33 healthy Japanese adults (NCT04461483); 24 adults in Part 1 (single-dose soticlestat 200-1200 mg or placebo) and 9 in Part 2 (soticlestat 100-300 mg twice daily or placebo for 21 days). PK sample collection was paired with 12-lead electrocardiogram data from continuous Holter recordings. The concentration-QTc relationship was analysed using a linear mixed-effects model. QTc prolongation safety margins were determined for two scenarios of calculated high clinical exposures: scenario 1 (NCT05064449) involved coadministration of single-dose soticlestat 300 mg with itraconazole or mefenamic acid and scenario 2 (NCT05098054) involved single-dose soticlestat 300 mg administration in participants with mild/moderate hepatic impairment (implementing a 3-fold dose reduction for moderate severity).

Based on concentration-QTc analysis, placebo-corrected change-from-baseline QT values (90% confidence intervals), corrected for heart rate (Fridericia's method), were 0.94 ms (-2.35, 4.23) for soticlestat and 0.63 ms (-3.15, 4.41) for its N-oxide metabolite plasma concentrations at therapeutic doses (soticlestat 300 mg twice daily); safety margins were >2-fold for scenarios of calculated high clinical exposures. No (Part 1) and five (83.3%; Part 2) participants experienced treatment-emergent adverse events (all mild).

There was no evidence for QT prolongation with soticlestat at therapeutic doses or in two scenarios of high clinical exposures, which resulted in regulatory agencies waiving requirements of a thorough QT study. Safety/PK findings aligned with previous soticlestat clinical studies.