Clinical Evaluation of the Effect of Aficamten on QT/QTc Interval in Healthy Participants

ABSTRACT Aficamten is a next‐in‐class, small‐molecule, cardiac myosin inhibitor in development for treating hypertrophic cardiomyopathy (HCM). This 2‐part study evaluated aficamten's impact on QTc interval in healthy participants. Part A (n = 10) was an open‐label study to find the appropriate...

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Main Authors: Neha Maharao, Donghong Xu, Tyrell J. Simkins, Owen Bowles, Genzhou Liu, Youcef Benattia, Adrienne Griffith, Stephen B. Heitner, Stuart Kupfer, Polina German
Format: Article
Language:English
Published: Wiley 2025-04-01
Series:Clinical and Translational Science
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Online Access:https://doi.org/10.1111/cts.70218
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author Neha Maharao
Donghong Xu
Tyrell J. Simkins
Owen Bowles
Genzhou Liu
Youcef Benattia
Adrienne Griffith
Stephen B. Heitner
Stuart Kupfer
Polina German
author_facet Neha Maharao
Donghong Xu
Tyrell J. Simkins
Owen Bowles
Genzhou Liu
Youcef Benattia
Adrienne Griffith
Stephen B. Heitner
Stuart Kupfer
Polina German
author_sort Neha Maharao
collection DOAJ
description ABSTRACT Aficamten is a next‐in‐class, small‐molecule, cardiac myosin inhibitor in development for treating hypertrophic cardiomyopathy (HCM). This 2‐part study evaluated aficamten's impact on QTc interval in healthy participants. Part A (n = 10) was an open‐label study to find the appropriate dose for thorough QT (TQT) evaluation in Part B. Part B (n = 34) was a double‐blind, 3‐way crossover TQT study conducted as per ICH E14 guidance using negative (placebo) and positive (moxifloxacin) controls. A single 50 mg aficamten dose achieved exposures (Cmax range: 124–1660 ng/mL) comparable to the highest clinical dose (20 mg QD) in obstructive HCM patients (NCT05186818; [Cmax range: 131–1230 ng/mL]) and was chosen for TQT evaluation. Using concentration‐QT (C‐QT) modeling, the placebo‐ and baseline‐corrected QT interval using Fridericia's correction (ΔΔQTcF) was −1.82 msec (90% CI: −3.43, −0.214) at peak aficamten concentrations (298.3 ng/mL) following the 50 mg dose. The 90% CI upper bound of ΔΔQTcF for aficamten was < 10 msec at all post‐dose time points. Assay sensitivity was established by the 90% CI lower bound for moxifloxacin (ΔΔQTcF) exceeding 5 msec. Aficamten did not cause QTc prolongation (using C‐QT and by time point analyses) within observed plasma concentrations up to 1660 ng/mL (aficamten), 213 ng/mL (metabolite CK‐3834282), and 343 ng/mL (metabolite CK‐3834283). No clinically meaningful effect on electrocardiogram parameters, including absolute QTcF (≤ 450 msec) and change from baseline in QTcF (≤ 30 msec) was noted in aficamten‐treated participants. Aficamten was generally well tolerated. In conclusion, there was no evidence of aficamten‐mediated QTc prolongation across the therapeutic concentration range in a formal TQT study.
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spelling doaj-art-c997a24c000943ecb71643ee83cdb7fd2025-08-20T02:18:43ZengWileyClinical and Translational Science1752-80541752-80622025-04-01184n/an/a10.1111/cts.70218Clinical Evaluation of the Effect of Aficamten on QT/QTc Interval in Healthy ParticipantsNeha Maharao0Donghong Xu1Tyrell J. Simkins2Owen Bowles3Genzhou Liu4Youcef Benattia5Adrienne Griffith6Stephen B. Heitner7Stuart Kupfer8Polina German9Department of Clinical Pharmacology Cytokinetics, Incorporated South San Francisco California USADepartment of Clinical Pharmacology Cytokinetics, Incorporated South San Francisco California USADepartment of Clinical Research Cytokinetics, Incorporated South San Francisco California USADepartment of Clinical Operations Cytokinetics, Incorporated South San Francisco California USADepartment of Biostatistics Cytokinetics, Incorporated South San Francisco California USADepartment of Drug Safety and Pharmacovigilance Cytokinetics, Incorporated South San Francisco California USADepartment of Clinical Pharmacology Cytokinetics, Incorporated South San Francisco California USADepartment of Clinical Research Cytokinetics, Incorporated South San Francisco California USADepartment of Clinical Research Cytokinetics, Incorporated South San Francisco California USADepartment of Clinical Pharmacology Cytokinetics, Incorporated South San Francisco California USAABSTRACT Aficamten is a next‐in‐class, small‐molecule, cardiac myosin inhibitor in development for treating hypertrophic cardiomyopathy (HCM). This 2‐part study evaluated aficamten's impact on QTc interval in healthy participants. Part A (n = 10) was an open‐label study to find the appropriate dose for thorough QT (TQT) evaluation in Part B. Part B (n = 34) was a double‐blind, 3‐way crossover TQT study conducted as per ICH E14 guidance using negative (placebo) and positive (moxifloxacin) controls. A single 50 mg aficamten dose achieved exposures (Cmax range: 124–1660 ng/mL) comparable to the highest clinical dose (20 mg QD) in obstructive HCM patients (NCT05186818; [Cmax range: 131–1230 ng/mL]) and was chosen for TQT evaluation. Using concentration‐QT (C‐QT) modeling, the placebo‐ and baseline‐corrected QT interval using Fridericia's correction (ΔΔQTcF) was −1.82 msec (90% CI: −3.43, −0.214) at peak aficamten concentrations (298.3 ng/mL) following the 50 mg dose. The 90% CI upper bound of ΔΔQTcF for aficamten was < 10 msec at all post‐dose time points. Assay sensitivity was established by the 90% CI lower bound for moxifloxacin (ΔΔQTcF) exceeding 5 msec. Aficamten did not cause QTc prolongation (using C‐QT and by time point analyses) within observed plasma concentrations up to 1660 ng/mL (aficamten), 213 ng/mL (metabolite CK‐3834282), and 343 ng/mL (metabolite CK‐3834283). No clinically meaningful effect on electrocardiogram parameters, including absolute QTcF (≤ 450 msec) and change from baseline in QTcF (≤ 30 msec) was noted in aficamten‐treated participants. Aficamten was generally well tolerated. In conclusion, there was no evidence of aficamten‐mediated QTc prolongation across the therapeutic concentration range in a formal TQT study.https://doi.org/10.1111/cts.70218cardiovascular diseasephase 1QTQTc intervalsafety
spellingShingle Neha Maharao
Donghong Xu
Tyrell J. Simkins
Owen Bowles
Genzhou Liu
Youcef Benattia
Adrienne Griffith
Stephen B. Heitner
Stuart Kupfer
Polina German
Clinical Evaluation of the Effect of Aficamten on QT/QTc Interval in Healthy Participants
Clinical and Translational Science
cardiovascular disease
phase 1
QT
QTc interval
safety
title Clinical Evaluation of the Effect of Aficamten on QT/QTc Interval in Healthy Participants
title_full Clinical Evaluation of the Effect of Aficamten on QT/QTc Interval in Healthy Participants
title_fullStr Clinical Evaluation of the Effect of Aficamten on QT/QTc Interval in Healthy Participants
title_full_unstemmed Clinical Evaluation of the Effect of Aficamten on QT/QTc Interval in Healthy Participants
title_short Clinical Evaluation of the Effect of Aficamten on QT/QTc Interval in Healthy Participants
title_sort clinical evaluation of the effect of aficamten on qt qtc interval in healthy participants
topic cardiovascular disease
phase 1
QT
QTc interval
safety
url https://doi.org/10.1111/cts.70218
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