A Dose Escalation Study of Gefapixant (AF-219/MK-7264) in Refractory Chronic Cough (MK-7264-010)

Phase 2

Completed

Conditions: Refractory Chronic Cough

Interventions: Drug: Gefapixant
Drug: Placebo (for gefapixant)

Registration Number: NCT02349425

Lead Sponsor: Afferent Pharmaceuticals, Inc., a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA)

Brief Summary: A randomized, double-blind, placebo-controlled, crossover, dose escalation study to assess the efficacy and tolerability of gefapixant (AF-219; MK-7264) in participants with refractory chronic cough.

Detailed Description: Not available

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 59

Inclusion Criteria

Chest radiograph or computed tomography (CT) thorax within the last 12 months not demonstrating any abnormality considered to be significantly contributing to the chronic cough
Refractory chronic cough for at least one year: a cough that is unresponsive to at least 8 weeks of targeted treatment for identified underlying triggers including reflux disease, asthma and post-nasal drip or unexplained cough: a cough for which no objective evidence of an underlying trigger can be determined after investigation
Score of ≥ 40 mm on the Cough Severity Visual Analog Scale (VAS) at Screening
Women of child-bearing potential must use 2 forms of acceptable birth control method from Screening through the Follow-Up Visit.
Male participants and their partners of child-bearing potential must use 2 methods of acceptable birth control from Screening until 3 months after the last dose of study drug.
Written informed consent.
Willing and able to comply with all aspects of the protocol.

Exclusion Criteria

Current smoker
Individuals who have given up smoking within the past 6 months, or those with >20 pack-year smoking history
Treatment with an angiotensin converting enzyme (ACE)-inhibitor as the potential cause of a participant's cough, or requiring treatment with an ACE-inhibitor during the study or within 4 weeks prior to the Baseline Visit (Day 0)
Forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) < 60%
History of upper respiratory tract infection or recent significant change in pulmonary status within 4 weeks of the Baseline Visit (Day 0)
History of opioid use within 1 week of the Baseline Visit (Day 0)
Requiring concomitant therapy with prohibited medications
Body mass index (BMI) <18 kg/m^2 or ≥ 37 kg/m^2
History of concurrent malignancy or recurrence of malignancy within 2 years prior to Screening (not including participants with <3 excised basal cell carcinomas)
History of a diagnosis of drug or alcohol dependency or abuse within approximately the last 3 years
Any condition possibly affecting drug absorption (e.g., gastrectomy, gastroplasty, any type of bariatric surgery, vagotomy, or bowel resection)
Screening systolic blood pressure (SBP) >160 mmHg or a diastolic blood pressure (DBP) >90 mmHg
Clinically significant abnormal electrocardiogram (ECG) at Screening
Personal or family history of congenital long QT syndrome or family history of sudden death
Cardiac pacemaker
Significantly abnormal laboratory tests at Screening
Breastfeeding
Treatment with an investigational drug (except gefapixant) or biologic within 60 days preceding the first dose of study medication or plans to take another investigational drug or biologic within 30 days of study completion
Blood donation within 56 days or plasma donation within 7 days prior to dosing
Other severe, acute, or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with trial participation or investigational product administration or may interfere with the interpretation of trial results

Study & Design

Study Type: INTERVENTIONAL

Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Cohort 1: Gefapixant>Placebo	Placebo (for gefapixant)	50, 100, 150, and 200 mg gefapixant twice daily (BID) for 4 days each in Period 1 and placebo BID for 16 days in Period 2. For Cohort 1, there was a 3 to 7 day washout period between treatment periods.
Cohort 1: Placebo>Gefapixant	Placebo (for gefapixant)	Placebo BID for 16 days in Period 1 and gefapixant 50, 100, 150, and 200 mg BID for 4 days each in Period 2. For Cohort 1, there was a 3 to 7 day washout period between treatment periods.
Cohort 2: Gefapixant>Placebo	Placebo (for gefapixant)	Gefapixant 7.5, 15, 30, and 50 mg BID for 4 days each in Period 1 and placebo BID for 16 days in Period 2. For Cohort 2, there was a 14 to 21 day washout period between treatment periods.
Cohort 2: Placebo>Gefapixant	Placebo (for gefapixant)	Placebo BID for 16 days in Period 1 and gefapixant 7.5, 15, 30, and 50 mg BID for 4 days each in Period 2. For Cohort 2, there was a 14 to 21 day washout period between treatment periods.
Cohort 1: Gefapixant>Placebo	Gefapixant	50, 100, 150, and 200 mg gefapixant twice daily (BID) for 4 days each in Period 1 and placebo BID for 16 days in Period 2. For Cohort 1, there was a 3 to 7 day washout period between treatment periods.
Cohort 1: Placebo>Gefapixant	Gefapixant	Placebo BID for 16 days in Period 1 and gefapixant 50, 100, 150, and 200 mg BID for 4 days each in Period 2. For Cohort 1, there was a 3 to 7 day washout period between treatment periods.
Cohort 2: Gefapixant>Placebo	Gefapixant	Gefapixant 7.5, 15, 30, and 50 mg BID for 4 days each in Period 1 and placebo BID for 16 days in Period 2. For Cohort 2, there was a 14 to 21 day washout period between treatment periods.
Cohort 2: Placebo>Gefapixant	Gefapixant	Placebo BID for 16 days in Period 1 and gefapixant 7.5, 15, 30, and 50 mg BID for 4 days each in Period 2. For Cohort 2, there was a 14 to 21 day washout period between treatment periods.

Primary Outcome Measures

Name	Time	Method
Change in Awake Objective Cough Frequency on Log-transformed Scale - Cohort 1	Period 1 (while awake): baseline (Day 0) and 24 hours after Day 4, 8, 12 & 16 doses; Period 2 (while awake): baseline (Day 22) and 24 hours after Day 26, 30, 34 and 38 doses	Awake Objective Frequency (per hour) is the total number of cough events during the monitoring period (in general, 24-hr interval) the participant is awake divided by the total duration (in hours) for the monitoring period the participant is awake. 24-hour sound recordings were collected using a digital recording device.
Change in Awake Objective Cough Frequency on Log-transformed Scale - Cohort 2	Period 1 (while awake): baseline (Day 0) and 24 hours after Day 4, 8, 12 & 16 doses; Period 2 (while awake): baseline (Day 22) and 24 hours after Day 26, 30, 34 and 38 doses	Awake Objective Frequency (per hour) is the total number of cough events during the monitoring period (in general, 24-hr interval) the participant is awake divided by the total duration (in hours) for the monitoring period the participant is awake. 24-hour sound recordings were collected using a digital recording device.
Percent Change From Baseline in Awake Cough Frequency for Cohort 1	Period 1 (while awake): baseline (Day 0) and 24 hours after Day 4, 8, 12 & 16 doses; Period 2 (while awake): baseline (Day 22) and 24 hours after Day 26, 30, 34 and 38 doses	Awake Objective Cough Frequency (per hour) is the total number of cough events during the monitoring period (in general, 24-hr interval) the participant is awake divided by the total duration (in hours) for the monitoring period the participant is awake. 24-hour sound recordings were collected using a digital recording device. Percent Change in Awake Cough Frequency is the change from baseline in awake cough frequency x 100, divided by baseline awake cough frequency. A negative result indicates a decrease in cough frequency, while a positive result indicates an increase in cough frequency.
Percent Change From Baseline in Awake Cough Frequency for Cohort 2	Period 1 (while awake): baseline (Day 0) and 24 hours after Day 4, 8, 12 & 16 doses; Period 2 (while awake): baseline (Day 22) and 24 hours after Day 26, 30, 34 and 38 doses	Awake Objective Cough Frequency (per hour) is the total number of cough events during the monitoring period (in general, 24-hr interval) the participant is awake divided by the total duration (in hours) for the monitoring period the participant is awake. 24-hour sound recordings were collected using a digital recording device. Percent Change in Awake Cough Frequency is the change from baseline in awake cough frequency x 100, divided by baseline awake cough frequency. A negative result indicates a decrease in cough frequency, while a positive result indicates an increase in cough frequency.
Responder Analysis of Awake Cough Frequency for Cohort 1	Period 1 (while awake): baseline (Day 0) and 24 hours after Day 4, 8, 12 & 16 doses; Period 2 (while awake): baseline (Day 22) and 24 hours after Day 26, 30, 34 and 38 doses	Participants were classified as responders based on the magnitude of the percent change from baseline in Awake Objective cough frequency: 1. ≥70% Reduction=1 if Percent Change from Baseline in cough frequency at the end of the dosing interval ≤-70.0%; 0 Otherwise; 2. ≥50% Reduction=1 if Percent Change from Baseline in cough frequency at the end of the dosing interval ≤ -50.0%; 0 Otherwise; 3. ≥30% Reduction=1 if Percent Change from Baseline in cough frequency at the end of the dosing interval ≤ -30.0%; 0 Otherwise. These responder definitions were not mutually exclusive. A participant who achieved a 1 for ≥70% Reduction for a particular period and dosing interval, were by definition, classified as ≥50% Reduction and ≥ 30% Reduction.
Responder Analysis of Awake Cough Frequency for Cohort 2	Period 1 (while awake): baseline (Day 0) and 24 hours after Day 4, 8, 12 & 16 doses; Period 2 (while awake): baseline (Day 22) and 24 hours after Day 26, 30, 34 and 38 doses	Participants were classified as responders based on the magnitude of the percent change from baseline in Awake Objective cough frequency: 1. ≥70% Reduction=1 if Percent Change from Baseline in cough frequency at the end of the dosing interval ≤-70.0%; 0 Otherwise; 2. ≥50% Reduction=1 if Percent Change from Baseline in cough frequency at the end of the dosing interval ≤ -50.0%; 0 Otherwise; 3. ≥30% Reduction=1 if Percent Change from Baseline in cough frequency at the end of the dosing interval ≤ -30.0%; 0 Otherwise. These responder definitions were not mutually exclusive. A participant who achieved a 1 for ≥70% Reduction for a particular period and dosing interval, were by definition, classified as ≥50% Reduction and ≥ 30% Reduction.

Secondary Outcome Measures

Name	Time	Method
Change From Baseline in Awake (0-8 Hours) Objective Cough Frequency for Cohort 1	Period 1 (while awake): baseline (Day 0) and 0-8 hours after Day 4, 8, 12 & 16 doses; Period 2 (while awake): baseline (Day 22) and 0-8 hours after Day 26, 30, 34 and 38 doses	Awake (0-8 hours) Objective Cough Frequency is the total number of cough events during the monitoring period the participant was awake for the first 8 hours after the participant took their study medication divided by 8 or the total duration (in hours) for the monitoring period the participant was awake whichever is less. 24-hour sound recordings were collected using a digital recording device. Results are change from baseline: a negative result indicates a decrease in cough frequency, while a positive result indicates an increase in cough frequency. Cough frequency was analyzed using a mixed model repeated measures (MMRM) to evaluate the results of the 2-period cross-over study. The derived change measured at each dose were the repeated measures.
Change From Baseline of Cough Visual Analogue Scale (VAS) Score for Cohort 1	Screening; Period 1: baseline (Day 0) and Day 4, 8, 12 & 16; Period 2: baseline (Day 22) and Day 26, 30, 34, 38 and 39	Cough VAS is scored from 0 to 100 using a 10 mm visual analogue scale with 0 at 0mm and 100 at 10mm with 0 (no cough) and 100 (most severe cough). Baseline cough VAS is defined as average of screening and baseline cough VAS. Results are change from baseline: a negative result indicates a decrease in cough severity, while a positive result indicates an increase in cough severity. Cough VAS was analyzed using MMRM to evaluate the results of the 2-period cross-over study. The derived change measured at each dose were the repeated measures.
Change From Baseline in Awake (0-8 Hours) Objective Cough Frequency for Cohort 2	Period 1 (while awake): baseline (Day 0) and 0-8 hours after Day 4, 8, 12 & 16 doses; Period 2 (while awake): baseline (Day 22) and 0-8 hours after Day 26, 30, 34 and 38 doses	Awake (0-8 hours) Objective Cough Frequency is the total number of cough events during the monitoring period the participant was awake for the first 8 hours after the participant took their study medication divided by 8 or the total duration (in hours) for the monitoring period the participant was awake whichever is less. 24-hour sound recordings were collected using a digital recording device. Results are change from baseline: a negative result indicates a decrease in cough frequency, while a positive result indicates an increase in cough frequency. Cough frequency was analyzed using a mixed model repeated measures (MMRM) to evaluate the results of the 2-period cross-over study. The derived change measured at each dose were the repeated measures.
Change From Baseline in Total (24 Hours) Cough Frequency - Cohort 1	Period 1: baseline (Day 0) and 0-24 hours after Day 4, 8, 12 & 16 doses; Period 2: baseline (Day 22) and 0-24 hours after Day 26, 30, 34 and 38 doses	Total (0-24 hours) Objective Cough Frequency is the total number of cough events during the monitoring period divided by the total duration (in hours, i.e., 24 hours mostly) for the monitoring period. 24-hour sound recordings were collected using a digital recording device. Results are change from baseline: a negative result indicates a decrease in cough frequency, while a positive result indicates an increase in cough frequency. Cough frequency was analyzed using MMRM to evaluate the results of the 2-period cross-over study. The derived change measured at each dose were the repeated measures.
Change From Baseline in Total (24 Hours) Cough Frequency - Cohort 2	Period 1: baseline (Day 0) and 0-24 hours after Day 4, 8, 12 & 16 doses; Period 2: baseline (Day 22) and 0-24 hours after Day 26, 30, 34 and 38 doses	Total (0-24 hours) Objective Cough Frequency is the total number of cough events during the monitoring period divided by the total duration (in hours, i.e., 24 hours mostly) for the monitoring period. 24-hour sound recordings were collected using a digital recording device. Results are change from baseline: a negative result indicates a decrease in cough frequency, while a positive result indicates an increase in cough frequency. Cough frequency was analyzed using MMRM to evaluate the results of the 2-period cross-over study. The derived change measured at each dose were the repeated measures.
Change From Baseline in Sleep Cough Frequency - Cohort 1	Period 1 (while asleep): baseline (Day 0) and 24 hours after Day 4, 8, 12 & 16 doses; Period 2 (while asleep): baseline (Day 22) and 24 hours after Day 26, 30, 34 and 38 doses	Sleep Objective Cough Frequency is the total number of cough events during the monitoring period the participant is asleep divided by the total duration (in hours) for the monitoring period the participant is asleep. 24-hour sound recording were collected with a digital recording device. Results are change from baseline: a negative result indicates a decrease in cough frequency, while a positive result indicates an increase in cough frequency. Cough frequency was analyzed using MMRM to evaluate the results of the 2-period cross-over study. The derived change measured at each dose were the repeated measures.
Change From Baseline in Sleep Cough Frequency - Cohort 2	Period 1 (while asleep): baseline (Day 0) and 24 hours after Day 4, 8, 12 & 16 doses; Period 2 (while asleep): baseline (Day 22) and 24 hours after Day 26, 30, 34 and 38 doses	Sleep Objective Cough Frequency is the total number of cough events during the monitoring period the participant is asleep divided by the total duration (in hours) for the monitoring period the participant is asleep. 24-hour sound recording were collected with a digital recording device. Results are change from baseline: a negative result indicates a decrease in cough frequency, while a positive result indicates an increase in cough frequency. Cough frequency was analyzed using MMRM to evaluate the results of the 2-period cross-over study. The derived change measured at each dose were the repeated measures.
Change From Baseline of the Mean Total Daily Cough Severity Diary (CSD) Score for Cohort 1	Screening; Period 1: baseline (Day 0) and Days 1-17; Period 2: baseline (Day 22) and Days 23-39	The daily CSD Score is calculated using the daily CSD instrument, a 7-item, disease specific, patient-reported outcome measure with a recall period of "today" (the current day). The measure evaluates frequency of cough (3 items); intensity of cough (2 items); and sleep disruption due to cough (2 items). Each of these 7 items is rated on an 11-point scale, ranging from 0 (best) to 10 (worst), with higher scores indicating greater severity. The total daily CSD score is the sum of these 7 item scores (Min=0, Max=70). Baseline CSD score = average of CSD scores at screening and baseline. Results are change from baseline: a negative result indicates a decrease in cough severity, while a positive result indicates an increase in cough severity. CSD was analyzed using MMRM to evaluate the results of the 2-period cross-over study. The derived change measured at each dose were the repeated measures.
Change From Baseline of the Mean Total Daily Cough Severity Diary (CSD) Score for Cohort 2	Screening; Period 1: baseline (Day 0) and Days 1-17; Period 2: baseline (Day 22) and Days 23-39	The daily CSD Score is calculated using the daily CSD instrument, a 7-item, disease specific, patient-reported outcome measure with a recall period of "today" (the current day). The measure evaluates frequency of cough (3 items); intensity of cough (2 items); and sleep disruption due to cough (2 items). Each of these 7 items is rated on an 11-point scale, ranging from 0 (best) to 10 (worst), with higher scores indicating greater severity. The total daily CSD score is the sum of these 7 item scores (Min=0, Max=70). Baseline CSD score = average of CSD scores at screening and baseline. Results are change from baseline: a negative result indicates a decrease in cough severity, while a positive result indicates an increase in cough severity. CSD was analyzed using MMRM to evaluate the results of the 2-period cross-over study. The derived change measured at each dose were the repeated measures.
Change From Baseline at End of Treatment Period Leicester Cough Questionnaire (LCQ): Individual Domain and Total Scores for Cohort 1 and 2	Period 1: Day 0 (baseline) and Day 17; Period 2: Day 22 (baseline) and Day 39	The LCQ-Acute is a 19-item health-related quality-of-life (HRQoL) questionnaire specific for acute cough which contains three domains (i.e., physical, psychological, and social). It is calculated as a mean score for each domain ranging from 1 (worst) to 7 (best), and total score ranging from 3 (worst) to 21 (best). Each item on the LCQ-acute assesses symptoms or the impact of symptoms on HRQoL in the last 24 hours using a 7-point Likert scale ranging from 1 to 7. Higher scores indicate better HRQoL. Participants' perception of their cough severity was assessed, based on the LCQ-Acute score, at Baseline and last day of dose. LCQ was analyzed using MMRM to evaluate the results of the 2-period cross-over study. The derived change measured at each dose were the repeated measures.
Change From Baseline of Cough Visual Analogue Scale (VAS) Score for Cohort 2	Screening; Period 1: baseline (Day 0) and Day 4, 8, 12 & 16; Period 2: baseline (Day 22) and Day 26, 30, 34, 38 and 39	Cough VAS is scored from 0 to 100 using a 10 mm visual analogue scale with 0 at 0mm and 100 at 10mm with 0 (no cough) and 100 (most severe cough). Baseline cough VAS is defined as average of screening and baseline cough VAS. Results are change from baseline: a negative result indicates a decrease in cough severity, while a positive result indicates an increase in cough severity. Cough VAS was analyzed using MMRM to evaluate the results of the 2-period cross-over study. The derived change measured at each dose were the repeated measures.