Trial · NCT03482713

Study of Gefapixant (MK-7264) in Adult Japanese Participants With Unexplained or Refractory Chronic Cough (MK-7264-033)

NCT03482713, Phase 2, Completed, Merck Sharp & Dohme LLC; results first posted 2019-07-05

3 sourcestrials-2026-11-12-0.5.0

Cite this record

ConductScience Library. Study of Gefapixant (MK-7264) in Adult Japanese Participants With Unexplained or Refractory Chronic Cough (MK-7264-033). Trials, record NCT03482713. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT03482713

On this page

Trial

As registered on ClinicalTrials.gov, in the graph's capture of the registry.

Title: Study of Gefapixant (MK-7264) in Adult Japanese Participants With Unexplained or Refractory Chronic Cough (MK-7264-033)
NCT number: NCT03482713
Status: Completed
Phases: Phase 2
Enrollment: 23 participants, actual
Lead sponsor: Merck Sharp & Dohme LLC
Conditions: Chronic Cough
Interventions: Gefapixant 45 mg, Placebo
First posted: 2018-03-29
Last updated: 2019-10-17
Results first posted: 2019-07-05

Source ClinicalTrials.gov

Registered outcomes4

Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.

List	Outcome	Time frame	Description
Primary	Number of Participants Who Experienced an Adverse Event	Up to 6 weeks	An adverse event is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment.
Primary	Number of Participants Who Discontinued Study Treatment Due to an Adverse Event	Up to 4 weeks	An adverse event is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment.
Secondary	Change From Baseline at Week 4 in Log-transformed 24-hour Coughs Per Hour	Baseline and Week 4	Cough frequency will be evaluated using a digital recording device which records sounds from the lungs and trachea through a chest contact sensor, as well as ambient sounds through a lapel microphone. Change from baseline in log-transformed 24-hour coughs per hour = log (24-hour coughs per hour at post-baseline) - log (24-hour coughs per hour at baseline). The denominators may be different if the recording period is actually \<24 hours but ≥20 hours).
Secondary	Change From Baseline at Week 4 in Log-transformed Awake Coughs Per Hour	Baseline and Week 4	Change from baseline at Week 4 in awake coughs per hour is the average hourly cough frequency (based on sound recordings) during the 24-hour monitoring period while the participant is awake. Change from baseline in log-transformed awake coughs per hour = log (awake coughs per hour at post-baseline) - log (awake coughs per hour at baseline) for the monitoring period the participant is awake.

Source ClinicalTrials.gov

Outcomes4

Each outcome the trial posted results for, in ClinicalTrials.gov's words.

Type	Outcome	Time frame	Population	Units	Measured as
PRIMARY	Number of Participants Who Experienced an Adverse Event	Up to 6 weeks	All randomized participants who received at least one dose of study treatment.	Participants	COUNT_OF_PARTICIPANTS
PRIMARY	Number of Participants Who Discontinued Study Treatment Due to an Adverse Event	Up to 4 weeks	All randomized participants who received at least one dose of study treatment.	Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Change From Baseline at Week 4 in Log-transformed 24-hour Coughs Per Hour	Baseline and Week 4	All randomized participants who have taken at least one dose of study medication and provided at least one baseline and one post-baseline 24-hour cough observations during the treatment period.	Coughs/hour	LEAST_SQUARES_MEAN
SECONDARY	Change From Baseline at Week 4 in Log-transformed Awake Coughs Per Hour	Baseline and Week 4	All randomized participants who have taken at least one dose of study medication and provided at least one baseline and one post-baseline awake cough observations during the treatment period.	Coughs/hour	LEAST_SQUARES_MEAN

Source ClinicalTrials.gov

Results by group8

Each measurement the trial posted, group by group, in the words and numbers it posted.

Outcome	Group	Value	Spread	Units
Number of Participants Who Experienced an Adverse Event	Gefapixant 45 mg	9		Participants
Number of Participants Who Experienced an Adverse Event	Placebo	2		Participants
Number of Participants Who Discontinued Study Treatment Due to an Adverse Event	Gefapixant 45 mg	1		Participants
Number of Participants Who Discontinued Study Treatment Due to an Adverse Event	Placebo	0		Participants
Change From Baseline at Week 4 in Log-transformed 24-hour Coughs Per Hour	Gefapixant 45 mg	-0.23	Standard Error 0.39	Coughs/hour
Change From Baseline at Week 4 in Log-transformed 24-hour Coughs Per Hour	Placebo	-1.02	Standard Error 0.38	Coughs/hour
Change From Baseline at Week 4 in Log-transformed Awake Coughs Per Hour	Gefapixant 45 mg	-0.20	Standard Error 0.38	Coughs/hour
Change From Baseline at Week 4 in Log-transformed Awake Coughs Per Hour	Placebo	-0.97	Standard Error 0.37	Coughs/hour

Source ClinicalTrials.gov

Participant flow6

How many started, completed or left each group, period by period.

Period	Milestone	Group	Participants
Overall Study	STARTED	Gefapixant 45 mg	11
Overall Study	STARTED	Placebo	12
Overall Study	COMPLETED	Gefapixant 45 mg	11
Overall Study	COMPLETED	Placebo	12
Overall Study	NOT COMPLETED	Gefapixant 45 mg	0
Overall Study	NOT COMPLETED	Placebo	0

Source ClinicalTrials.gov

Adverse events30

Each adverse event the trial posted, group by group: the participants affected out of those at risk.

Type	Event	Organ system	Group	Affected	At risk	Events
other	Lymphadenitis	Blood and lymphatic system disorders	Gefapixant 45 mg	0	11	0
other	Lymphadenitis	Blood and lymphatic system disorders	Placebo	1	12	1
other	Palpitations	Cardiac disorders	Gefapixant 45 mg	1	11	1
other	Palpitations	Cardiac disorders	Placebo	0	12	0
other	Deafness neurosensory	Ear and labyrinth disorders	Gefapixant 45 mg	0	11	0
other	Deafness neurosensory	Ear and labyrinth disorders	Placebo	1	12	1
other	Gastritis	Gastrointestinal disorders	Gefapixant 45 mg	1	11	1
other	Gastritis	Gastrointestinal disorders	Placebo	0	12	0
other	Oral discomfort	Gastrointestinal disorders	Gefapixant 45 mg	1	11	1
other	Oral discomfort	Gastrointestinal disorders	Placebo	0	12	0

1 to 10 of 30Source ClinicalTrials.gov

See all 30 adverse events

Adverse event totals6

The totals the trial posted for each group.

Total	Group	Affected	At risk
Total, all-cause mortality	Gefapixant 45 mg	0	11
Total, all-cause mortality	Placebo	0	12
Total, other adverse events	Gefapixant 45 mg	9	11
Total, other adverse events	Placebo	2	12
Total, serious adverse events	Gefapixant 45 mg	0	11
Total, serious adverse events	Placebo	0	12

Source ClinicalTrials.gov

Papers0

The papers the trial lists on ClinicalTrials.gov.

None in this release.

Grants0

The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.

None in this release.

Trial comparisons4

Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.

Comparison	Source
Gefapixant 45 mg vs Placebo: Number of Participants Who Experienced an Adverse Event	Trial comparisons
Gefapixant 45 mg vs Placebo: Number of Participants Who Discontinued Study Treatment Due to an Adverse Event	Trial comparisons
Gefapixant 45 mg vs Placebo: deaths from any cause	Trial comparisons
Gefapixant 45 mg vs Placebo: serious adverse events	Trial comparisons

Tests0

The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.

None in this release.

Data dates

The day each source was copied for this release.

ClinicalTrials.gov: 2026-11-12; ClinicalTrials.gov
Results, from AACT: 2026-03-23; AACT
NIH grant links: 2026-11-13; NIH RePORTER

Sources 3

ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
ClinicalTrials.govNo license stated
NIH RePORTER's clinical studies and project filesPublic domain

Each source's terms

ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
ClinicalTrials.govnone stated
NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)

ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.

For software

Read this trial from software.

The record and each of its lists are JSON, twenty rows a page. No key.

GET https://conductscience.org/api/trials/v1/NCT03482713

GET https://conductscience.org/api/trials/v1/NCT03482713/events?page=2

API reference For AI assistants