Trial Outcomes & Findings for Study to Assess the Effect of Omecamtiv Mecarbil (OM) on QT/QTc Intervals in Healthy Adults (NCT NCT04175808)

NCT ID: NCT04175808

Last Updated: 2025-03-30

Results Overview

Continuous 12-lead digital ECG recording was performed on day 1 of each period. ECGs were analyzed by a blinded, central reader. At each specified timepoint, ten 14-second 12-lead ECG tracings were extracted from the continuous recordings. The median QT in each replicate was calculated; the mean of available medians was used as the participant's reportable value at that timepoint. QT interval was corrected for heart rate using Fridericia's correction (QTcF). Change from baseline (ΔQTcF) was calculated based on a linear mixed-effects model with period, sequence, time (categorical), treatment, and time-by-treatment interaction as fixed effects and baseline QTcF as covariate. Placebo-corrected ΔQTcF (ΔΔQTcF) was calculated as the adjusted mean ΔQTcF after OM dosing minus adjusted mean ΔQTcF after placebo. If the upper bound of the confidence interval of ΔΔQTcF was \< 10 ms for all post-dose time points, OM was to be concluded to not have a significant effect on QT interval prolongation.

• Recruitment status: COMPLETED
• Study phase: PHASE1
• Target enrollment: 70 participants
• Primary outcome timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose
• Results posted on: 2025-03-30

Participant Flow

Participants were enrolled at a single site in the United Kingdom. The study consisted of 2 parts: Part A and Part B. Part A was a lead-in phase to ensure that omecamtiv mecarbil (OM) plasma concentrations in Part B would not exceed 1000 ng/mL.

Participants in Part A received a single oral dose of 25 mg omecamtiv mecarbil; participants with maximum observed OM plasma concentration (Cmax) ≤ 350 ng/mL were eligible to enter Part B. Part B was a 3-period cross-over study in which all participants received a single dose of placebo, omecamtiv mecarbil, and moxifloxacin in 1 of 6 sequences, each separated by a washout of at least 7 days.

Participant milestones

Measure	Part A After an overnight fast of at least 10 hours participants received a single oral dose of 25 mg omecamtiv mecarbil on Day 1.	Part B: Placebo/OM/Moxifloxacin Participants received a single dose of placebo oral solution in Period 1, 50 mg omecamtiv mecarbil oral solution in Period 2 and 400 mg moxifloxacin oral tablet in Period 3. Each treatment was separated by a washout period of at least 7 days.	Part B: OM/Moxifloxacin/Placebo Participants received a single dose of 50 mg omecamtiv mecarbil oral solution in Period 1, 400 mg moxifloxacin oral tablet in Period 2, and placebo oral solution in Period 3. Each treatment was separated by a washout period of at least 7 days.	Part B: Moxifloxacin/Placebo/OM Participants received a single dose of 400 mg moxifloxacin oral tablet in Period 1, placebo oral solution in Period 2, and 50 mg omecamtiv mecarbil oral solution in Period 3. Each treatment was separated by a washout period of at least 7 days.	Part B: Placebo/Moxifloxacin/OM Participants received a single dose of placebo oral solution in Period 1, 400 mg moxifloxacin oral tablet in Period 2, and 50 mg omecamtiv mecarbil oral solution in Period 3. Each treatment was separated by a washout period of at least 7 days.	Part B: Moxifloxacin/OM/Placebo Participants received a single dose of 400 mg moxifloxacin oral tablet in Period 1, 50 mg omecamtiv mecarbil oral solution in Period 2, and placebo oral solution in Period 3. Each treatment was separated by a washout period of at least 7 days.	Part B: OM/Placebo/Moxifloxacin Participants received a single dose of 50 mg omecamtiv mecarbil oral solution in Period 1, placebo oral solution in Period 2, and 400 mg moxifloxacin oral tablet in Period 3. Each treatment was separated by a washout period of at least 7 days.
Part A STARTED	70	0	0	0	0	0	0
Part A COMPLETED	68	0	0	0	0	0	0
Part A NOT COMPLETED	2	0	0	0	0	0	0
Part B STARTED	0	10	10	10	10	10	10
Part B COMPLETED	0	10	10	10	10	10	10
Part B NOT COMPLETED	0	0	0	0	0	0	0

Reasons for withdrawal

Measure	Part A After an overnight fast of at least 10 hours participants received a single oral dose of 25 mg omecamtiv mecarbil on Day 1.	Part B: Placebo/OM/Moxifloxacin Participants received a single dose of placebo oral solution in Period 1, 50 mg omecamtiv mecarbil oral solution in Period 2 and 400 mg moxifloxacin oral tablet in Period 3. Each treatment was separated by a washout period of at least 7 days.	Part B: OM/Moxifloxacin/Placebo Participants received a single dose of 50 mg omecamtiv mecarbil oral solution in Period 1, 400 mg moxifloxacin oral tablet in Period 2, and placebo oral solution in Period 3. Each treatment was separated by a washout period of at least 7 days.	Part B: Moxifloxacin/Placebo/OM Participants received a single dose of 400 mg moxifloxacin oral tablet in Period 1, placebo oral solution in Period 2, and 50 mg omecamtiv mecarbil oral solution in Period 3. Each treatment was separated by a washout period of at least 7 days.	Part B: Placebo/Moxifloxacin/OM Participants received a single dose of placebo oral solution in Period 1, 400 mg moxifloxacin oral tablet in Period 2, and 50 mg omecamtiv mecarbil oral solution in Period 3. Each treatment was separated by a washout period of at least 7 days.	Part B: Moxifloxacin/OM/Placebo Participants received a single dose of 400 mg moxifloxacin oral tablet in Period 1, 50 mg omecamtiv mecarbil oral solution in Period 2, and placebo oral solution in Period 3. Each treatment was separated by a washout period of at least 7 days.	Part B: OM/Placebo/Moxifloxacin Participants received a single dose of 50 mg omecamtiv mecarbil oral solution in Period 1, placebo oral solution in Period 2, and 400 mg moxifloxacin oral tablet in Period 3. Each treatment was separated by a washout period of at least 7 days.
Part A Miscellaneous	2	0	0	0	0	0	0

Baseline Characteristics

Study to Assess the Effect of Omecamtiv Mecarbil (OM) on QT/QTc Intervals in Healthy Adults

Baseline characteristics by cohort

Measure	Part B n=60 Participants Participants with a maximum observed OM plasma concentration ≤ 350 ng/mL in Part A were randomly assigned to receive a single dose of each the following 3 treatments in one of six treatment sequences: * Placebo * 50 mg omecamtiv mecarbil * 400 mg moxifloxacin Each treatment was separated by a washout of at least 7 days.
Age, Continuous	32.7 years STANDARD_DEVIATION 8.88 • n=93 Participants
Sex: Female, Male Female	26 Participants n=93 Participants
Sex: Female, Male Male	34 Participants n=93 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants n=93 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	60 Participants n=93 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=93 Participants
Race/Ethnicity, Customized White	49 Participants n=93 Participants
Race/Ethnicity, Customized Black or African American	6 Participants n=93 Participants
Race/Ethnicity, Customized Asian	4 Participants n=93 Participants
Race/Ethnicity, Customized Native Hawaiian or Other Pacific Islander	0 Participants n=93 Participants
Race/Ethnicity, Customized American Indian or Alaska Native	0 Participants n=93 Participants
Race/Ethnicity, Customized Multiple	1 Participants n=93 Participants
QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) Prior to OM dose	402.9 ms STANDARD_DEVIATION 18.27 • n=93 Participants
QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) Prior to moxifloxacin dose	402.4 ms STANDARD_DEVIATION 18.38 • n=93 Participants
QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) Prior to placebo dose	404.1 ms STANDARD_DEVIATION 19.06 • n=93 Participants
PR Interval Prior to OM dose	151.4 ms STANDARD_DEVIATION 22.48 • n=93 Participants
PR Interval Prior to moxifloxacin dose	150.7 ms STANDARD_DEVIATION 22.73 • n=93 Participants
PR Interval Prior to placebo dose	151.2 ms STANDARD_DEVIATION 24.20 • n=93 Participants
QRS Prior to OM dose	105.6 ms STANDARD_DEVIATION 5.74 • n=93 Participants
QRS Prior to moxifloxacin dose	105.8 ms STANDARD_DEVIATION 5.36 • n=93 Participants
QRS Prior to placebo dose	105.8 ms STANDARD_DEVIATION 5.52 • n=93 Participants
Heart Rate Prior to OM dose	59.2 beats/minute STANDARD_DEVIATION 7.87 • n=93 Participants
Heart Rate Prior to moxifloxacin dose	59.5 beats/minute STANDARD_DEVIATION 7.36 • n=93 Participants
Heart Rate Prior to placebo dose	58.6 beats/minute STANDARD_DEVIATION 8.03 • n=93 Participants

PRIMARY outcome

Timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose

Population: The QT/QTc analysis set included all participants who received at least 1 dose of study treatment with measurements at baseline as well as on-treatment with at least 1 postdose timepoint with a valid ΔQTcF value in Part B.

Continuous 12-lead digital ECG recording was performed on day 1 of each period. ECGs were analyzed by a blinded, central reader. At each specified timepoint, ten 14-second 12-lead ECG tracings were extracted from the continuous recordings. The median QT in each replicate was calculated; the mean of available medians was used as the participant's reportable value at that timepoint.

QT interval was corrected for heart rate using Fridericia's correction (QTcF). Change from baseline (ΔQTcF) was calculated based on a linear mixed-effects model with period, sequence, time (categorical), treatment, and time-by-treatment interaction as fixed effects and baseline QTcF as covariate.

Placebo-corrected ΔQTcF (ΔΔQTcF) was calculated as the adjusted mean ΔQTcF after OM dosing minus adjusted mean ΔQTcF after placebo.

If the upper bound of the confidence interval of ΔΔQTcF was < 10 ms for all post-dose time points, OM was to be concluded to not have a significant effect on QT interval prolongation.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Omecamtiv Mecarbil Dosing in Part B 0.25 hours post-dose	-2.6 ms Interval -3.87 to -1.24	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Omecamtiv Mecarbil Dosing in Part B 0.5 hours post-dose	-4.9 ms Interval -6.4 to -3.45	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Omecamtiv Mecarbil Dosing in Part B 0.75 hours post-dose	-5.8 ms Interval -7.34 to -4.18	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Omecamtiv Mecarbil Dosing in Part B 1 hour post-dose	-6.7 ms Interval -8.13 to -5.29	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Omecamtiv Mecarbil Dosing in Part B 1.5 hours post-dose	-4.5 ms Interval -5.95 to -2.98	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Omecamtiv Mecarbil Dosing in Part B 2 hours post-dose	-2.7 ms Interval -4.21 to -1.18	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Omecamtiv Mecarbil Dosing in Part B 3 hours post-dose	-1.5 ms Interval -2.96 to -0.1	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Omecamtiv Mecarbil Dosing in Part B 4 hours post-dose	-0.8 ms Interval -2.35 to 0.7	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Omecamtiv Mecarbil Dosing in Part B 8 hours post-dose	-2.2 ms Interval -4.1 to -0.24	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Omecamtiv Mecarbil Dosing in Part B 12 hours post-dose	-1.9 ms Interval -3.98 to 0.22	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Omecamtiv Mecarbil Dosing in Part B 24 hours post-dose	-1.2 ms Interval -2.68 to 0.3	—	—	—

SECONDARY outcome

Timeframe: Day 1 of the OM treatment period at pre-dose and 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, 24, 48, 72, 96, and 120 hours post-dose.

Population: The pharmacokinetic (PK) population for Part B consisted of all participants who received OM and had evaluable PK data.

Plasma samples at each timepoint were quantified using a validated liquid chromatography-tandem mass spectrometry method. The lower limit of quantification for plasma samples was 1 ng/mL.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Maximum Observed Plasma Concentration (Cmax) of Omecamtiv Mecarbil in Part B	416 ng/mL Geometric Coefficient of Variation 33.2	—	—	—

SECONDARY outcome

Timeframe: Day 1 of the OM treatment period at pre-dose and 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, 24, 48, 72, 96, and 120 hours post-dose.

Population: Part B PK population

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Time to Maximum Observed Plasma Concentration (Tmax) of Omecamtiv Mecarbil In Part B	0.583 hours Interval 0.333 to 1.08	—	—	—

SECONDARY outcome

Timeframe: Day 1 of the OM treatment period at pre-dose and 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, 24, 48, 72, 96, and 120 hours post-dose.

Population: Part B PK population

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Apparent Terminal Elimination Half-life (T1/2) of Omecamtiv Mecarbil in Part B	20.0 hours Geometric Coefficient of Variation 2.91	—	—	—

SECONDARY outcome

Timeframe: Day 1 of the OM treatment period at pre-dose and 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, 24, 48, 72, 96, and 120 hours post-dose.

Population: Part B PK population

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Apparent Total Plasma Clearance (CL/F) for Omecamtiv Mecarbil in Part B	10.4 L/h Geometric Coefficient of Variation 21.2	—	—	—

SECONDARY outcome

Timeframe: Day 1 of the OM treatment period at pre-dose and 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, 24, 48, 72, 96, and 120 hours post-dose.

Population: Part B PK population

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Apparent Volume of Distribution (VZ/F) for Omecamtiv Mecarbil in Part B	299 liters Geometric Coefficient of Variation 21.5	—	—	—

SECONDARY outcome

Timeframe: Day 1 of the OM treatment period at pre-dose and 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, 24, 48, 72, 96, and 120 hours post-dose.

Population: Part B PK population

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Area Under the Concentration-time Curve From Time 0 to the Time of Last Quantifiable Concentration (AUC0-t) for Omecamtiv Mecarbil in Part B	4710 h*ng/mL Geometric Coefficient of Variation 21.0	—	—	—

SECONDARY outcome

Timeframe: Day 1 of the OM treatment period at pre-dose and 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, 24, 48, 72, 96, and 120 hours post-dose.

Population: Part B PK population

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
AUC From Time 0 to Infinity (AUCinf) for Omecamtiv Mecarbil in Part B	4790 h*ng/mL Geometric Coefficient of Variation 21.2	—	—	—

SECONDARY outcome

Timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the moxifloxacin treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: The QT/QTc analysis set

Assay sensitivity was validated by analysis of ∆QTcF of moxifloxacin. Continuous 12-lead digital ECG recording was performed on Day 1 of each period. ECGs were analyzed by a blinded, central reader. At each specified timepoint, ten 14-second 12-lead ECG tracings were extracted from the continuous recordings. The median QT in each replicate was calculated; the mean of available medians was used as the participant's reportable value at that timepoint.

QT interval was corrected for heart rate using Fridericia's correction (QTcF). Change from baseline (ΔQTcF) was calculated based on a linear mixed-effects model with period, sequence, time (categorical), treatment, and time-by-treatment interaction as fixed effects and baseline QTcF as covariate.

Placebo-corrected ΔQTcF (ΔΔQTcF) was calculated as the adjusted mean ΔQTcF after moxifloxacin dosing minus adjusted mean ΔQTcF after placebo.

If ∆∆QTcF was larger than 5 ms at 2, 3, or 4 hours, assay sensitivity was considered to be demonstrated.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Moxifloxacin Dosing in Part B 0.25 hours post-dose	2.2 ms Interval 0.89 to 3.53	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Moxifloxacin Dosing in Part B 0.5 hours post-dose	8.6 ms Interval 7.11 to 10.05	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Moxifloxacin Dosing in Part B 0.75 hours post-dose	10.1 ms Interval 8.51 to 11.67	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Moxifloxacin Dosing in Part B 1 hour post-dose	10.2 ms Interval 8.74 to 11.58	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Moxifloxacin Dosing in Part B 1.5 hours post-dose	11.1 ms Interval 9.61 to 12.59	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Moxifloxacin Dosing in Part B 2 hours post-dose	12.7 ms Interval 11.13 to 14.17	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Moxifloxacin Dosing in Part B 3 hours post-dose	13.1 ms Interval 11.71 to 14.57	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Moxifloxacin Dosing in Part B 4 hours post-dose	12.9 ms Interval 11.37 to 14.42	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Moxifloxacin Dosing in Part B 8 hours post-dose	9.7 ms Interval 7.75 to 11.62	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Moxifloxacin Dosing in Part B 12 hours post-dose	9.0 ms Interval 6.85 to 11.06	—	—	—
Placebo-corrected Change From Baseline in QT Interval Corrected for Heart Rate Based on the Fridericia Method (QTcF) After Moxifloxacin Dosing in Part B 24 hours post-dose	5.3 ms Interval 3.78 to 6.76	—	—	—

SECONDARY outcome

Timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the OM treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: The QT/QTc analysis set

Change from baseline in heart rate (HR) was calculated based on a linear mixed-effects model with period, sequence, time (categorical), treatment, and time-by-treatment interaction as fixed effects and baseline HR as a covariate.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 0.25 hours post-dose	1.3 bpm Interval 0.37 to 2.16	—	—	—
Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 0.5 hours post-dose	1.2 bpm Interval 0.38 to 2.12	—	—	—
Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 0.75 hours post-dose	1.4 bpm Interval 0.51 to 2.37	—	—	—
Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 1 hour post-dose	0.2 bpm Interval -0.86 to 1.18	—	—	—
Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 1.5 hours post-dose	-0.5 bpm Interval -1.44 to 0.46	—	—	—
Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 2 hours post-dose	-0.2 bpm Interval -1.1 to 0.77	—	—	—
Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 3 hours post-dose	1.1 bpm Interval 0.09 to 2.09	—	—	—
Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 4 hours post-dose	1.8 bpm Interval 0.77 to 2.84	—	—	—
Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 8 hours post-dose	7.8 bpm Interval 6.57 to 9.11	—	—	—
Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 12 hours post-dose	8.3 bpm Interval 7.07 to 9.55	—	—	—
Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 24 hours post-dose	2.8 bpm Interval 1.66 to 3.95	—	—	—

SECONDARY outcome

Timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the OM treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: The QT/QTc analysis set

Change from baseline in QTcF was calculated based on a linear mixed-effects model with period, sequence, time (categorical), treatment, and time-by-treatment interaction as fixed effects and baseline QTcF as a covariate.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Change From Baseline in QTcF After Omecamtiv Mecarbil Dosing in Part B 0.25 hours post-dose	-6.3 ms Interval -7.38 to -5.25	—	—	—
Change From Baseline in QTcF After Omecamtiv Mecarbil Dosing in Part B 0.5 hours post-dose	-9.1 ms Interval -10.3 to -7.98	—	—	—
Change From Baseline in QTcF After Omecamtiv Mecarbil Dosing in Part B 0.75 hours post-dose	-8.6 ms Interval -9.84 to -7.38	—	—	—
Change From Baseline in QTcF After Omecamtiv Mecarbil Dosing in Part B 1 hour post-dose	-8.1 ms Interval -9.23 to -6.99	—	—	—
Change From Baseline in QTcF After Omecamtiv Mecarbil Dosing in Part B 1.5 hours post-dose	-5.5 ms Interval -6.66 to -4.33	—	—	—
Change From Baseline in QTcF After Omecamtiv Mecarbil Dosing in Part B 2 hours post-dose	-5.2 ms Interval -6.4 to -4.02	—	—	—
Change From Baseline in QTcF After Omecamtiv Mecarbil Dosing in Part B 3 hours post-dose	-4.9 ms Interval -6.04 to -3.78	—	—	—
Change From Baseline in QTcF After Omecamtiv Mecarbil Dosing in Part B 4 hours post-dose	-3.3 ms Interval -4.51 to -2.12	—	—	—
Change From Baseline in QTcF After Omecamtiv Mecarbil Dosing in Part B 8 hours post-dose	-7.1 ms Interval -8.55 to -5.64	—	—	—
Change From Baseline in QTcF After Omecamtiv Mecarbil Dosing in Part B 12 hours post-dose	-6.6 ms Interval -8.18 to -5.04	—	—	—
Change From Baseline in QTcF After Omecamtiv Mecarbil Dosing in Part B 24 hours post-dose	-4.1 ms Interval -5.23 to -2.89	—	—	—

SECONDARY outcome

Timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the OM treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: The QT/QTc analysis set

The PR interval is the time from the onset of the P-wave to the start of the next QRS complex. Change from baseline was calculated based on a linear mixed-effects model with period, sequence, time (categorical), treatment, and time-by-treatment interaction as fixed effects and baseline PR interval as covariate.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 0.25 hours post-dose	-0.5 ms Interval -1.76 to 0.67	—	—	—
Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 0.5 hours post-dose	1.0 ms Interval -0.2 to 2.24	—	—	—
Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 0.75 hours post-dose	0.4 ms Interval -0.87 to 1.76	—	—	—
Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 1 hour post-dose	0.4 ms Interval -1.02 to 1.75	—	—	—
Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 1.5 hours post-dose	-1.2 ms Interval -2.4 to -0.08	—	—	—
Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 2 hours post-dose	-0.8 ms Interval -2.16 to 0.6	—	—	—
Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 3 hours post-dose	-2.0 ms Interval -3.37 to -0.67	—	—	—
Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 4 hours post-dose	-3.2 ms Interval -4.64 to -1.77	—	—	—
Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 8 hours post-dose	-7.5 ms Interval -9.28 to -5.67	—	—	—
Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 12 hours post-dose	-7.8 ms Interval -9.69 to -5.96	—	—	—
Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 24 hours post-dose	-2.1 ms Interval -3.71 to -0.58	—	—	—

SECONDARY outcome

Timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the OM treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: The QT/QTc analysis set

The QRS complex is a combination of the Q wave, R wave and S wave on an ECG tracing, and represents ventricular depolarization. Change from baseline was calculated based on a linear mixed-effects model with period, sequence, time (categorical), treatment, and time-by-treatment interaction as fixed effects and baseline QRS as covariate.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 0.25 hours post-dose	-0.2 ms Interval -0.42 to -0.01	—	—	—
Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 0.5 hours post-dose	0.0 ms Interval -0.28 to 0.22	—	—	—
Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 0.75 hours post-dose	-0.2 ms Interval -0.37 to 0.02	—	—	—
Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 1 hour post-dose	0.0 ms Interval -0.28 to 0.33	—	—	—
Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 1.5 hours post-dose	-0.2 ms Interval -0.41 to 0.06	—	—	—
Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 2 hours post-dose	-0.3 ms Interval -0.51 to -0.02	—	—	—
Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 3 hours post-dose	0.00 ms Interval -0.26 to 0.18	—	—	—
Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 4 hours post-dose	0.1 ms Interval -0.14 to 0.34	—	—	—
Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 8 hours post-dose	-0.4 ms Interval -0.8 to 0.03	—	—	—
Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 12 hours post-dose	-0.7 ms Interval -1.03 to -0.32	—	—	—
Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 24 hours post-dose	-0.3 ms Interval -0.61 to 0.08	—	—	—

SECONDARY outcome

Timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the OM treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: The PK/QTc analysis set included all participants who were in both the QT/QTc and PK analysis sets with at least 1 pair of post-dose PK and QTcF data from the same timepoint.

The relationship between omecamtiv mecarbil plasma concentration and ΔQTcF was investigated by linear mixed-effects modeling with ΔQTcF as the dependent variable, time-matched concentration of OM as the explanatory variable (0 for placebo), centered baseline QTcF (i.e., baseline QTcF for individual subject minus the population mean baseline QTcF for all subjects in the same period) as an additional covariate, study treatment (OM = 1 or placebo = 0) and time (i.e., post-dose time point) as fixed effects, and a random intercept and slope per subject. From the model, the slope (i.e., the regression parameter for the concentration) was estimated together with the 2-sided 90% CI.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Slope of Omecamtiv Mecarbil Plasma Concentration Estimated From Concentration-QTc Analysis in Part B	-0.011 ms per ng/mL Interval -0.0154 to -0.0073	—	—	—

SECONDARY outcome

Timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the OM treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: The QT/QTc analysis set

Change from baseline in heart rate (ΔHR) was calculated based on a linear mixed-effects model with period, sequence, time (categorical), treatment, and time-by-treatment interaction as fixed effects and baseline HR as covariate.

Placebo-corrected ΔHR (ΔΔHR) was calculated as the adjusted mean ΔHR after OM dosing minus adjusted mean ΔHR after placebo dosing.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Placebo-corrected Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 0.25 hours post-dose	-0.9 bpm Interval -1.84 to 0.09	—	—	—
Placebo-corrected Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 0.5 hours post-dose	-1.3 bpm Interval -2.27 to -0.42	—	—	—
Placebo-corrected Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 0.75 hours post-dose	-0.6 bpm Interval -1.68 to 0.4	—	—	—
Placebo-corrected Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 1 hour post-dose	-2.3 bpm Interval -3.54 to -1.15	—	—	—
Placebo-corrected Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 1.5 hours post-dose	-1.9 bpm Interval -2.93 to -0.78	—	—	—
Placebo-corrected Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 2 hours post-dose	-1.5 bpm Interval -2.57 to -0.47	—	—	—
Placebo-corrected Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 3 hours post-dose	-0.9 bpm Interval -2.02 to 0.3	—	—	—
Placebo-corrected Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 4 hours post-dose	0.5 bpm Interval -0.71 to 1.74	—	—	—
Placebo-corrected Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 8 hours post-dose	-0.1 bpm Interval -1.72 to 1.49	—	—	—
Placebo-corrected Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 12 hours post-dose	-1.0 bpm Interval -2.57 to 0.55	—	—	—
Placebo-corrected Change From Baseline in Heart Rate After Omecamtiv Mecarbil Dosing in Part B 24 hours post-dose	-1.7 bpm Interval -3.09 to -0.28	—	—	—

SECONDARY outcome

Timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the OM treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: The QT/QTc analysis set

Change from baseline in PR interval (ΔPR) was calculated based on a linear mixed-effects model with period, sequence, time (categorical), treatment, and time-by-treatment interaction as fixed effects and baseline PR interval as covariate.

Placebo-corrected ΔPR (ΔΔPR) was calculated as the adjusted mean ΔPR after OM dosing minus adjusted mean ΔPR after placebo dosing.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Placebo-corrected Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 0.25 hours post-dose	0.6 ms Interval -1.02 to 2.26	—	—	—
Placebo-corrected Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 0.5 hours post-dose	0.9 ms Interval -0.74 to 2.54	—	—	—
Placebo-corrected Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 0.75 hours post-dose	-0.3 ms Interval -2.07 to 1.5	—	—	—
Placebo-corrected Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 1 hour post-dose	1.0 ms Interval -0.89 to 2.87	—	—	—
Placebo-corrected Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 1.5 hours post-dose	0.1 ms Interval -1.46 to 1.64	—	—	—
Placebo-corrected Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 2 hours post-dose	1.9 ms Interval -0.02 to 3.74	—	—	—
Placebo-corrected Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 3 hours post-dose	0.4 ms Interval -1.41 to 2.26	—	—	—
Placebo-corrected Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 4 hours post-dose	0.1 ms Interval -1.83 to 2.09	—	—	—
Placebo-corrected Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 8 hours post-dose	-1.6 ms Interval -4.12 to 0.88	—	—	—
Placebo-corrected Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 12 hours post-dose	-1.0 ms Interval -3.57 to 1.61	—	—	—
Placebo-corrected Change From Baseline in PR Interval After Omecamtiv Mecarbil Dosing in Part B 24 hours post-dose	-0.1 ms Interval -2.22 to 2.08	—	—	—

SECONDARY outcome

Timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the OM treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: The QT/QTc analysis set

Change from baseline in QRS (ΔQRS) was calculated based on a linear mixed-effects model with period, sequence, time (categorical), treatment, and time-by-treatment interaction as fixed effects and baseline QRS as covariate.

Placebo-corrected ΔQRS (ΔΔQRS) was calculated as the adjusted mean ΔQRS after OM dosing minus adjusted mean ΔQRS after placebo dosing.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Placebo-corrected Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 0.25 hours post-dose	-0.1 ms Interval -0.34 to 0.21	—	—	—
Placebo-corrected Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 0.5 hours post-dose	-0.1 ms Interval -0.41 to 0.28	—	—	—
Placebo-corrected Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 0.75 hours post-dose	-0.1 ms Interval -0.33 to 0.2	—	—	—
Placebo-corrected Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 1 hour post-dose	-0.1 ms Interval -0.53 to 0.32	—	—	—
Placebo-corrected Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 1.5 hours post-dose	0.0 ms Interval -0.33 to 0.32	—	—	—
Placebo-corrected Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 2 hours post-dose	0.1 ms Interval -0.28 to 0.39	—	—	—
Placebo-corrected Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 3 hours post-dose	0.1 ms Interval -0.18 to 0.41	—	—	—
Placebo-corrected Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 4 hours post-dose	0.1 ms Interval -0.22 to 0.44	—	—	—
Placebo-corrected Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 8 hours post-dose	0.3 ms Interval -0.32 to 0.85	—	—	—
Placebo-corrected Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 12 hours post-dose	0.4 ms Interval -0.07 to 0.91	—	—	—
Placebo-corrected Change From Baseline in QRS After Omecamtiv Mecarbil Dosing in Part B 24 hours post-dose	-0.1 ms Interval -0.6 to 0.36	—	—	—

SECONDARY outcome

Timeframe: Day 1 of the OM treatment period at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: QT/QTc analysis set

Outliers were predefined according to the following categories:

QTcF:

Treatment-emergent value of > 450 and ≤ 480 ms when not present at baseline (new onset) Treatment-emergent value of > 480 and ≤ 500 ms when not present at baseline (new onset) Treatment-emergent value of > 500 ms when not present at baseline (new onset) Increase of QTcF from baseline of > 30 and ≤ 60 ms Increase of QTcF from baseline > 60 ms Increase of PR from baseline > 25% resulting in PR > 200 ms Increase of QRS from baseline > 25% resulting in QRS > 120 ms Decrease of HR from baseline > 25% resulting in HR < 50 bpm Increase of HR from baseline > 25% resulting in HR > 100 bpm

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Number of Participants With Recorded Outlier Values for QTcF, HR, PR, and QRS After Omecamtiv Mecarbil Dosing in Part B QTcF > 450 and ≤ 480 ms (new onset)	1 Participants	—	—	—
Number of Participants With Recorded Outlier Values for QTcF, HR, PR, and QRS After Omecamtiv Mecarbil Dosing in Part B QTcF > 480 and ≤ 500 ms (new onset)	0 Participants	—	—	—
Number of Participants With Recorded Outlier Values for QTcF, HR, PR, and QRS After Omecamtiv Mecarbil Dosing in Part B QTcF > 500 ms (new onset)	0 Participants	—	—	—
Number of Participants With Recorded Outlier Values for QTcF, HR, PR, and QRS After Omecamtiv Mecarbil Dosing in Part B Increase in ΔQTcF > 30 and ≤ 60 ms	0 Participants	—	—	—
Number of Participants With Recorded Outlier Values for QTcF, HR, PR, and QRS After Omecamtiv Mecarbil Dosing in Part B Increase in ΔQTcF > 60 ms	0 Participants	—	—	—
Number of Participants With Recorded Outlier Values for QTcF, HR, PR, and QRS After Omecamtiv Mecarbil Dosing in Part B HR < 50 bpm with a decrease in ΔHR > 25%	0 Participants	—	—	—
Number of Participants With Recorded Outlier Values for QTcF, HR, PR, and QRS After Omecamtiv Mecarbil Dosing in Part B HR > 100 bpm with an increase in ΔHR > 25%	0 Participants	—	—	—
Number of Participants With Recorded Outlier Values for QTcF, HR, PR, and QRS After Omecamtiv Mecarbil Dosing in Part B PR > 200 ms with an increase in ΔPR > 25%	0 Participants	—	—	—
Number of Participants With Recorded Outlier Values for QTcF, HR, PR, and QRS After Omecamtiv Mecarbil Dosing in Part B QRS > 120 ms with an increase in ΔQRS > 25%	0 Participants	—	—	—

SECONDARY outcome

Timeframe: Day 1 of the OM treatment period at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: QT/QTc analysis set

T-wave abnormalities were categorized as follows:

Flat T-wave: T amplitude < 1 mm (either positive or negative) including flat isoelectric line Notched T-wave (+): Presence of notch(es) of at least 0.05 mV amplitude on ascending or descending arm of the positive T-wave Biphasic: T-wave that contains a second component with an opposite phase that is at least 0.1 mV deep (both positive/negative and negative/positive and polyphasic T-waves included) Normal T-wave (-): T amplitude that is negative, without biphasic T-wave or notches Notched T-wave (-): Presence of notch(es) of at least 0.05 mV amplitude on descending or ascending arm of the negative T-wave U waves: Presence of abnormal U-waves

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Number of Participants With Treatment-emergent Changes in T-wave Morphology and U-wave Presence After Omecamtiv Mecarbil Dosing in Part B Flat T-wave	0 Participants	—	—	—
Number of Participants With Treatment-emergent Changes in T-wave Morphology and U-wave Presence After Omecamtiv Mecarbil Dosing in Part B Notched T-wave (+)	0 Participants	—	—	—
Number of Participants With Treatment-emergent Changes in T-wave Morphology and U-wave Presence After Omecamtiv Mecarbil Dosing in Part B Biphasic T-wave	0 Participants	—	—	—
Number of Participants With Treatment-emergent Changes in T-wave Morphology and U-wave Presence After Omecamtiv Mecarbil Dosing in Part B Normal T-wave (-)	0 Participants	—	—	—
Number of Participants With Treatment-emergent Changes in T-wave Morphology and U-wave Presence After Omecamtiv Mecarbil Dosing in Part B Notched T-wave (-)	0 Participants	—	—	—
Number of Participants With Treatment-emergent Changes in T-wave Morphology and U-wave Presence After Omecamtiv Mecarbil Dosing in Part B U-Wave presence	0 Participants	—	—	—

SECONDARY outcome

Timeframe: From first dose of study treatment to day 6 of each treatment period

Population: The safety population included all participants who received at least 1 dose of study treatment (OM, placebo, or moxifloxacin) and had at least 1 postdose safety assessment.

A TEAE was defined as an adverse event (AE) that started during or after the first dose, or started prior to the first dose and increased in severity after the first dose. A treatment-related TEAE was defined as a TEAE with a relationship of related to the study treatment as determined by the investigator.

The Investigator assessed the severity of each AE reported during the study based on the following grading scale:

Mild: Aware of sign or symptom, easily tolerated Moderate: Discomfort enough to cause interference with usual activity Severe: Incapacitating, inability to work or do usual activity

SAEs were defined as any untoward medical occurrence that met at least 1 of the following serious criteria:

• Resulted in Death
• Was life-threatening
• Required in-patient hospitalization or prolongation of existing hospitalization
• Resulted in persistent or significant disability/incapacity
• Was a congenital anomaly/birth defect
• Other medically important serious event

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=70 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo n=60 Participants Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg n=60 Participants Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Number of Participants With Treatment-emergent Adverse Events (TEAEs) Any TEAE	20 Participants	26 Participants	24 Participants	29 Participants
Number of Participants With Treatment-emergent Adverse Events (TEAEs) Serious TEAE	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Treatment-emergent Adverse Events (TEAEs) TEAE leading to discontinuation	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Treatment-emergent Adverse Events (TEAEs) TEAE leading to death	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Treatment-emergent Adverse Events (TEAEs) Mild TEAE	19 Participants	25 Participants	24 Participants	28 Participants
Number of Participants With Treatment-emergent Adverse Events (TEAEs) Moderate TEAE	2 Participants	1 Participants	1 Participants	2 Participants
Number of Participants With Treatment-emergent Adverse Events (TEAEs) Severe TEAE	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Treatment-emergent Adverse Events (TEAEs) Treatment-related TEAE	2 Participants	0 Participants	4 Participants	2 Participants
Number of Participants With Treatment-emergent Adverse Events (TEAEs) Treatment-related serious TEAE	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Treatment-emergent Adverse Events (TEAEs) Treatment-related TEAE leading to discontinuation	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Treatment-emergent Adverse Events (TEAEs) Treatment-related TEAE leading to death	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Treatment-emergent Adverse Events (TEAEs) Treatment-related mild TEAE	2 Participants	0 Participants	4 Participants	2 Participants
Number of Participants With Treatment-emergent Adverse Events (TEAEs) Treatment-related moderate TEAE	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Treatment-emergent Adverse Events (TEAEs) Treatment-related severe TEAE	0 Participants	0 Participants	0 Participants	0 Participants

SECONDARY outcome

Timeframe: From first dose up to day 6 of each treatment period

Population: Safety population

Blood and urine samples were collected for clinical laboratory evaluations (including clinical chemistry, hematology, urinalysis, and serology). Vital signs included blood pressure, pulse rate and body temperature. Standard safety 12-lead ECGs were recorded after the subject had been supine or semi-recumbent and at rest for at least 5 minutes to detect any immediate ECG effects for subject safety. These ECGs were viewed locally. The Investigator determined whether an abnormal value in an individual participant represented a clinically significant change from the participant's baseline values.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=70 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo n=60 Participants Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg n=60 Participants Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Number of Participants With Clinically Significant Abnormalities in Vital Signs, Laboratory Tests, or Electrocardiogram Findings Clinical Laboratory Evaluations	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Clinically Significant Abnormalities in Vital Signs, Laboratory Tests, or Electrocardiogram Findings Vital Signs	0 Participants	0 Participants	0 Participants	0 Participants
Number of Participants With Clinically Significant Abnormalities in Vital Signs, Laboratory Tests, or Electrocardiogram Findings 12-lead Electrocardiogram	0 Participants	0 Participants	0 Participants	0 Participants

POST_HOC outcome

Timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the OM treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: The QT/QTc analysis set

Change from baseline in QTcF was calculated based on a linear mixed-effects model with period, sequence, time (categorical), treatment, and time-by-treatment interaction as fixed effects and baseline QTcF as a covariate.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo n=60 Participants Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Change From Baseline in QTcF After Each Treatment In Part 2 0.25 hours post-dose	-6.3 ms Interval -7.38 to -5.25	-1.6 ms Interval -2.61 to -0.49	-3.8 ms Interval -4.82 to -2.7	—
Change From Baseline in QTcF After Each Treatment In Part 2 0.5 hours post-dose	-9.1 ms Interval -10.3 to -7.98	4.4 ms Interval 3.21 to 5.53	-4.2 ms Interval -5.37 to -3.05	—
Change From Baseline in QTcF After Each Treatment In Part 2 0.75 hours post-dose	-8.6 ms Interval -9.84 to -7.38	7.2 ms Interval 6.01 to 8.47	-2.8 ms Interval -4.08 to -1.62	—
Change From Baseline in QTcF After Each Treatment In Part 2 1 hour post-dose	-8.1 ms Interval -9.23 to -6.99	8.8 ms Interval 7.63 to 9.88	-1.4 ms Interval -2.52 to -0.28	—
Change From Baseline in QTcF After Each Treatment In Part 2 1.5 hours post-dose	-5.5 ms Interval -6.66 to -4.33	10.1 ms Interval 8.89 to 11.23	-1.0 ms Interval -2.2 to 0.13	—
Change From Baseline in QTcF After Each Treatment In Part 2 2 hours post-dose	-5.2 ms Interval -6.4 to -4.02	10.1 ms Interval 8.95 to 11.33	-2.5 ms Interval -3.7 to -1.33	—
Change From Baseline in QTcF After Each Treatment In Part 2 3 hours post-dose	-4.9 ms Interval -6.04 to -3.78	9.8 ms Interval 8.63 to 10.89	-3.4 ms Interval -4.51 to -2.25	—
Change From Baseline in QTcF After Each Treatment In Part 2 4 hours post-dose	-3.3 ms Interval -4.51 to -2.12	10.4 ms Interval 9.21 to 11.59	-2.5 ms Interval -3.68 to -1.3	—
Change From Baseline in QTcF After Each Treatment In Part 2 8 hours post-dose	-7.1 ms Interval -8.55 to -5.64	4.8 ms Interval 3.3 to 6.22	-4.9 ms Interval -6.38 to -3.47	—
Change From Baseline in QTcF After Each Treatment In Part 2 12 hours post-dose	-6.6 ms Interval -8.18 to -5.04	4.2 ms Interval 2.66 to 5.8	-4.7 ms Interval -6.3 to -3.16	—
Change From Baseline in QTcF After Each Treatment In Part 2 24 hours post-dose	-4.1 ms Interval -5.23 to -2.89	2.4 ms Interval 1.23 to 3.57	-2.9 ms Interval -4.04 to -1.7	—

POST_HOC outcome

Timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the OM treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: The QT/QTc analysis set

Change from baseline in heart rate (HR) was calculated based on a linear mixed-effects model with period, sequence, time (categorical), treatment, and time-by-treatment interaction as fixed effects and baseline HR as a covariate.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo n=60 Participants Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Change From Baseline in Heart Rate After Each Treatment In Part 2 0.25 hours post-dose	1.3 bpm Interval 0.37 to 2.16	2.1 bpm Interval 1.22 to 3.01	2.1 bpm Interval 1.25 to 3.04	—
Change From Baseline in Heart Rate After Each Treatment In Part 2 0.5 hours post-dose	1.2 bpm Interval 0.38 to 2.12	4.0 bpm Interval 3.14 to 4.88	2.6 bpm Interval 1.72 to 3.47	—
Change From Baseline in Heart Rate After Each Treatment In Part 2 0.75 hours post-dose	1.4 bpm Interval 0.51 to 2.37	5.3 bpm Interval 4.33 to 6.2	2.1 bpm Interval 1.15 to 3.01	—
Change From Baseline in Heart Rate After Each Treatment In Part 2 1 hour post-dose	0.2 bpm Interval -0.86 to 1.18	5.4 bpm Interval 4.39 to 6.43	2.5 bpm Interval 1.49 to 3.53	—
Change From Baseline in Heart Rate After Each Treatment In Part 2 1.5 hours post-dose	-0.5 bpm Interval -1.44 to 0.46	2.0 bpm Interval 1.06 to 2.97	1.4 bpm Interval 0.41 to 2.32	—
Change From Baseline in Heart Rate After Each Treatment In Part 2 2 hours post-dose	-0.2 bpm Interval -1.1 to 0.77	2.0 bpm Interval 1.05 to 2.93	1.4 bpm Interval 0.41 to 2.29	—
Change From Baseline in Heart Rate After Each Treatment In Part 2 3 hours post-dose	1.1 bpm Interval 0.09 to 2.09	3.0 bpm Interval 1.97 to 3.97	2.0 bpm Interval 0.96 to 2.95	—
Change From Baseline in Heart Rate After Each Treatment In Part 2 4 hours post-dose	1.8 bpm Interval 0.77 to 2.84	2.9 bpm Interval 1.88 to 3.95	1.3 bpm Interval 0.25 to 2.32	—
Change From Baseline in Heart Rate After Each Treatment In Part 2 8 hours post-dose	7.8 bpm Interval 6.57 to 9.11	9.1 bpm Interval 7.83 to 10.38	8.0 bpm Interval 6.69 to 9.22	—
Change From Baseline in Heart Rate After Each Treatment In Part 2 12 hours post-dose	8.3 bpm Interval 7.07 to 9.55	9.6 bpm Interval 8.37 to 10.85	9.3 bpm Interval 8.08 to 10.56	—
Change From Baseline in Heart Rate After Each Treatment In Part 2 24 hours post-dose	2.8 bpm Interval 1.66 to 3.95	3.4 bpm Interval 2.3 to 4.59	4.5 bpm Interval 3.34 to 5.63	—

POST_HOC outcome

Timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the OM treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: The QT/QTc analysis set

The PR interval is the time from the onset of the P-wave to the start of the next QRS complex. Change from baseline was calculated based on a linear mixed-effects model with period, sequence, time (categorical), treatment, and time-by-treatment interaction as fixed effects and baseline PR interval as covariate.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo n=60 Participants Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Change From Baseline in PR Interval After Each Treatment In Part 2 0.25 hours post-dose	-0.5 ms Interval -1.76 to 0.67	-1.6 ms Interval -2.85 to -0.42	-1.2 ms Interval -2.38 to 0.06	—
Change From Baseline in PR Interval After Each Treatment In Part 2 0.5 hours post-dose	1.0 ms Interval -0.2 to 2.24	-0.6 ms Interval -1.78 to 0.66	0.1 ms Interval -1.1 to 1.34	—
Change From Baseline in PR Interval After Each Treatment In Part 2 0.75 hours post-dose	0.4 ms Interval -0.87 to 1.76	-1.1 ms Interval -2.4 to 0.24	0.7 ms Interval -0.58 to 2.05	—
Change From Baseline in PR Interval After Each Treatment In Part 2 1 hour post-dose	0.4 ms Interval -1.02 to 1.75	-1.5 ms Interval -2.83 to -0.07	-0.6 ms Interval -2.0 to 0.76	—
Change From Baseline in PR Interval After Each Treatment In Part 2 1.5 hours post-dose	-1.2 ms Interval -2.4 to -0.08	-2.1 ms Interval -3.24 to -0.91	-1.3 ms Interval -2.48 to -0.17	—
Change From Baseline in PR Interval After Each Treatment In Part 2 2 hours post-dose	-0.8 ms Interval -2.16 to 0.6	-1.6 ms Interval -2.99 to -0.24	-2.6 ms Interval -4.02 to -1.26	—
Change From Baseline in PR Interval After Each Treatment In Part 2 3 hours post-dose	-2.0 ms Interval -3.37 to -0.67	-3.3 ms Interval -4.64 to -1.94	-2.5 ms Interval -3.8 to -1.1	—
Change From Baseline in PR Interval After Each Treatment In Part 2 4 hours post-dose	-3.2 ms Interval -4.64 to -1.77	-4.5 ms Interval -5.9 to -3.04	-3.3 ms Interval -4.77 to -1.9	—
Change From Baseline in PR Interval After Each Treatment In Part 2 8 hours post-dose	-7.5 ms Interval -9.28 to -5.67	-7.7 ms Interval -9.55 to -5.93	-5.8 ms Interval -7.65 to -4.04	—
Change From Baseline in PR Interval After Each Treatment In Part 2 12 hours post-dose	-7.8 ms Interval -9.69 to -5.96	-7.5 ms Interval -9.37 to -5.63	-6.8 ms Interval -8.72 to -4.98	—
Change From Baseline in PR Interval After Each Treatment In Part 2 24 hours post-dose	-2.1 ms Interval -3.71 to -0.58	-2.6 ms Interval -4.14 to -1.01	-2.1 ms Interval -3.64 to -0.51	—

POST_HOC outcome

Timeframe: Baseline (average of samples taken at -1.25, -1, and -0.75 hours predose on day 1 of the OM treatment period) and at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 8, 12, and 24 hours post-dose.

Population: The QT/QTc analysis set

The QRS complex is a combination of the Q wave, R wave and S wave on an ECG tracing, and represents ventricular depolarization. Change from baseline was calculated based on a linear mixed-effects model with period, sequence, time (categorical), treatment, and time-by-treatment interaction as fixed effects and baseline QRS as covariate.

Outcome measures

Measure	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Placebo n=60 Participants Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg n=60 Participants Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.
Change From Baseline in QRS After Each Treatment In Part 2 0.25 hours post-dose	-0.2 ms Interval -0.42 to -0.01	-0.2 ms Interval -0.43 to -0.02	-0.2 ms Interval -0.36 to 0.05	—
Change From Baseline in QRS After Each Treatment In Part 2 0.5 hours post-dose	0.0 ms Interval -0.28 to 0.22	-0.1 ms Interval -0.36 to 0.15	0.0 ms Interval -0.22 to 0.29	—
Change From Baseline in QRS After Each Treatment In Part 2 0.75 hours post-dose	-0.2 ms Interval -0.37 to 0.02	0.0 ms Interval -0.18 to 0.21	-0.1 ms Interval -0.31 to 0.08	—
Change From Baseline in QRS After Each Treatment In Part 2 1 hour post-dose	0.0 ms Interval -0.28 to 0.33	0.1 ms Interval -0.25 to 0.36	0.1 ms Interval -0.18 to 0.44	—
Change From Baseline in QRS After Each Treatment In Part 2 1.5 hours post-dose	-0.2 ms Interval -0.41 to 0.06	0.0 ms Interval -0.27 to 0.21	-0.2 ms Interval -0.41 to 0.07	—
Change From Baseline in QRS After Each Treatment In Part 2 2 hours post-dose	-0.3 ms Interval -0.51 to -0.02	0.1 ms Interval -0.16 to 0.33	-0.3 ms Interval -0.56 to -0.07	—
Change From Baseline in QRS After Each Treatment In Part 2 3 hours post-dose	0.00 ms Interval -0.26 to 0.18	0.1 ms Interval -0.15 to 0.29	-0.2 ms Interval -0.37 to 0.07	—
Change From Baseline in QRS After Each Treatment In Part 2 4 hours post-dose	0.1 ms Interval -0.14 to 0.34	0.2 ms Interval -0.04 to 0.44	0.0 ms Interval -0.25 to 0.23	—
Change From Baseline in QRS After Each Treatment In Part 2 8 hours post-dose	-0.4 ms Interval -0.8 to 0.03	-0.3 ms Interval -0.76 to 0.08	-0.6 ms Interval -1.07 to -0.23	—
Change From Baseline in QRS After Each Treatment In Part 2 12 hours post-dose	-0.7 ms Interval -1.03 to -0.32	-0.7 ms Interval -1.1 to -0.4	-1.1 ms Interval -1.45 to -0.74	—
Change From Baseline in QRS After Each Treatment In Part 2 24 hours post-dose	-0.3 ms Interval -0.61 to 0.08	0.0 ms Interval -0.35 to 0.33	-0.1 ms Interval -0.49 to 0.2	—

Adverse Events

Part A: Omecamtiv Mecarbil 25 mg

Serious events: 0 serious events

Other events: 14 other events

Deaths: 0 deaths

Part B: Placebo

Serious events: 0 serious events

Other events: 16 other events

Deaths: 0 deaths

Part B: Omecamtiv Mecarbil 50 mg

Serious events: 0 serious events

Other events: 13 other events

Deaths: 0 deaths

Part B: Moxifloxacin 400 mg

Serious events: 0 serious events

Other events: 18 other events

Deaths: 0 deaths

Overall

Serious events: 0 serious events

Other events: 39 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Measure	Part A: Omecamtiv Mecarbil 25 mg n=70 participants at risk After an overnight fast of at least 10 hours participants received a single oral dose of 25 mg omecamtiv mecarbil on Day 1.	Part B: Placebo n=60 participants at risk Participants received a single oral dose of placebo on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Omecamtiv Mecarbil 50 mg n=60 participants at risk Participants received a single oral dose of 50 mg OM on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Part B: Moxifloxacin 400 mg n=60 participants at risk Participants received a single dose of 400 mg moxifloxacin on day 1 of treatment period 1, 2, or 3, depending on sequence assignment.	Overall n=70 participants at risk ALL TREATED SUBJECTS
Gastrointestinal disorders Nausea	1.4% 1/70 • From first dose of study drug to 6 days post-dose in each treatment period.	6.7% 4/60 • From first dose of study drug to 6 days post-dose in each treatment period.	1.7% 1/60 • From first dose of study drug to 6 days post-dose in each treatment period.	5.0% 3/60 • From first dose of study drug to 6 days post-dose in each treatment period.	10.0% 7/70 • From first dose of study drug to 6 days post-dose in each treatment period.
Infections and infestations Nasopharyngitis	1.4% 1/70 • From first dose of study drug to 6 days post-dose in each treatment period.	1.7% 1/60 • From first dose of study drug to 6 days post-dose in each treatment period.	3.3% 2/60 • From first dose of study drug to 6 days post-dose in each treatment period.	0.00% 0/60 • From first dose of study drug to 6 days post-dose in each treatment period.	5.7% 4/70 • From first dose of study drug to 6 days post-dose in each treatment period.
Injury, poisoning and procedural complications Post procedural complication	5.7% 4/70 • From first dose of study drug to 6 days post-dose in each treatment period.	3.3% 2/60 • From first dose of study drug to 6 days post-dose in each treatment period.	5.0% 3/60 • From first dose of study drug to 6 days post-dose in each treatment period.	1.7% 1/60 • From first dose of study drug to 6 days post-dose in each treatment period.	14.3% 10/70 • From first dose of study drug to 6 days post-dose in each treatment period.
Injury, poisoning and procedural complications Post procedural erythema	2.9% 2/70 • From first dose of study drug to 6 days post-dose in each treatment period.	10.0% 6/60 • From first dose of study drug to 6 days post-dose in each treatment period.	8.3% 5/60 • From first dose of study drug to 6 days post-dose in each treatment period.	8.3% 5/60 • From first dose of study drug to 6 days post-dose in each treatment period.	21.4% 15/70 • From first dose of study drug to 6 days post-dose in each treatment period.
Injury, poisoning and procedural complications Procedural pain	0.00% 0/70 • From first dose of study drug to 6 days post-dose in each treatment period.	0.00% 0/60 • From first dose of study drug to 6 days post-dose in each treatment period.	1.7% 1/60 • From first dose of study drug to 6 days post-dose in each treatment period.	5.0% 3/60 • From first dose of study drug to 6 days post-dose in each treatment period.	5.7% 4/70 • From first dose of study drug to 6 days post-dose in each treatment period.
Musculoskeletal and connective tissue disorders Pain in extremity	0.00% 0/70 • From first dose of study drug to 6 days post-dose in each treatment period.	0.00% 0/60 • From first dose of study drug to 6 days post-dose in each treatment period.	0.00% 0/60 • From first dose of study drug to 6 days post-dose in each treatment period.	5.0% 3/60 • From first dose of study drug to 6 days post-dose in each treatment period.	4.3% 3/70 • From first dose of study drug to 6 days post-dose in each treatment period.
Nervous system disorders Dizziness	1.4% 1/70 • From first dose of study drug to 6 days post-dose in each treatment period.	3.3% 2/60 • From first dose of study drug to 6 days post-dose in each treatment period.	0.00% 0/60 • From first dose of study drug to 6 days post-dose in each treatment period.	3.3% 2/60 • From first dose of study drug to 6 days post-dose in each treatment period.	7.1% 5/70 • From first dose of study drug to 6 days post-dose in each treatment period.
Nervous system disorders Headache	1.4% 1/70 • From first dose of study drug to 6 days post-dose in each treatment period.	5.0% 3/60 • From first dose of study drug to 6 days post-dose in each treatment period.	5.0% 3/60 • From first dose of study drug to 6 days post-dose in each treatment period.	3.3% 2/60 • From first dose of study drug to 6 days post-dose in each treatment period.	12.9% 9/70 • From first dose of study drug to 6 days post-dose in each treatment period.
Psychiatric disorders Insomnia	1.4% 1/70 • From first dose of study drug to 6 days post-dose in each treatment period.	3.3% 2/60 • From first dose of study drug to 6 days post-dose in each treatment period.	3.3% 2/60 • From first dose of study drug to 6 days post-dose in each treatment period.	1.7% 1/60 • From first dose of study drug to 6 days post-dose in each treatment period.	8.6% 6/70 • From first dose of study drug to 6 days post-dose in each treatment period.
Respiratory, thoracic and mediastinal disorders Nasal congestion	1.4% 1/70 • From first dose of study drug to 6 days post-dose in each treatment period.	1.7% 1/60 • From first dose of study drug to 6 days post-dose in each treatment period.	0.00% 0/60 • From first dose of study drug to 6 days post-dose in each treatment period.	3.3% 2/60 • From first dose of study drug to 6 days post-dose in each treatment period.	5.7% 4/70 • From first dose of study drug to 6 days post-dose in each treatment period.
Respiratory, thoracic and mediastinal disorders Oropharyngeal pain	4.3% 3/70 • From first dose of study drug to 6 days post-dose in each treatment period.	0.00% 0/60 • From first dose of study drug to 6 days post-dose in each treatment period.	5.0% 3/60 • From first dose of study drug to 6 days post-dose in each treatment period.	1.7% 1/60 • From first dose of study drug to 6 days post-dose in each treatment period.	10.0% 7/70 • From first dose of study drug to 6 days post-dose in each treatment period.
Skin and subcutaneous tissue disorders Rash	1.4% 1/70 • From first dose of study drug to 6 days post-dose in each treatment period.	3.3% 2/60 • From first dose of study drug to 6 days post-dose in each treatment period.	0.00% 0/60 • From first dose of study drug to 6 days post-dose in each treatment period.	1.7% 1/60 • From first dose of study drug to 6 days post-dose in each treatment period.	5.7% 4/70 • From first dose of study drug to 6 days post-dose in each treatment period.
Skin and subcutaneous tissue disorders Rash papular	2.9% 2/70 • From first dose of study drug to 6 days post-dose in each treatment period.	1.7% 1/60 • From first dose of study drug to 6 days post-dose in each treatment period.	0.00% 0/60 • From first dose of study drug to 6 days post-dose in each treatment period.	1.7% 1/60 • From first dose of study drug to 6 days post-dose in each treatment period.	5.7% 4/70 • From first dose of study drug to 6 days post-dose in each treatment period.

Additional Information

Study Director

Amgen Inc.

Phone: 866-572-6436

Email: medinfo@amgen.com

Results disclosure agreements

• Principal investigator is a sponsor employee The Clinical Trial Agreement generally does not restrict an investigator's discussion of trial results after completion. The Agreement permits Amgen a limited period of time to review material discussing trial results (typically up to 45 days and possible extension). Amgen may remove confidential information, but authors have final control and approval of publication content. For multicenter studies, the investigator agrees not to publish any results before the first multi-center publication.
• Publication restrictions are in place

Restriction type: OTHER