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Chronic cough

2 published articles · Updated continuously

Clinical Trial Landscape

Clinical Trials for chronic cough

19 trials tracked for chronic cough: 7 in phase 3 or 4 and 5 with published results. The most-cited published study has 318 citations.

19Trials tracked

7Phase 3 & 4

0Recruiting

5With published results

Phase distribution

Phase 4 1 Phase 3 6 Phase 2 11 Other / NA 1

Phase 3 A Study of Gefapixant (MK-7264) in Adult Participants With Chronic Cough (MK-7264-030) Completed · 318 cited
Phase 3 A Study of Gefapixant (MK-7264) in Adult Participants With Chronic Cough (MK-7264-027) Completed · 316 cited
Phase 3 Efficacy and Safety of Gefapixant (MK-7264) in Adult Participants With Recent Onset Chronic Cough (MK-7264-043) Completed · 37 cited
Phase 3 A Study of Gefapixant (MK-7264) in Japanese Adult Participants With Refractory or Unexplained Chronic Cough (MK-7264-038) Completed · 14 cited
Phase 3 Efficacy and Safety of Gefapixant (MK-7264) in Women With Chronic Cough and Stress Urinary Incontinence (MK-7264-042) Completed · 10 cited
Phase 4 Mepolizumab for the Treatment of Chronic Cough With Eosinophilic Airways Diseases Completed

Show 13 more trials

Phase 3 A Study of Gefapixant (MK-7264) in Adult Participants With Chronic Cough (MK-7264-030)-China Extension Completed
Phase 2 Study of Gefapixant (MK-7264) in Adult Japanese Participants With Unexplained or Refractory Chronic Cough (MK-7264-033) Completed
Phase 2 Evaluation of S-600918 in Adults With Refractory Chronic Cough Completed
Phase 2 A Study to Assess the Efficacy of Gefapixant (MK-7264/AF-219), in Participants With Chronic Cough (MK-7264-006) Completed
Phase 2 A 12-Week Study in Participants With Refractory Chronic Cough (MK-7264-012) Completed
Phase 2 A Dose Escalation Study of Gefapixant (AF-219/MK-7264) in Refractory Chronic Cough (MK-7264-010) Completed
Phase 2 Study of the Efficacy, Safety, and Tolerability of Serlopitant for the Treatment of Refractory Chronic Cough Completed
Phase 2 An 8-Week Refractory Chronic Cough Study (MK-7264-021) Completed
Phase 2 Effect of Gefapixant (AF-219/MK-7264) on Cough Reflex Sensitivity (MK-7264-015) Completed
Phase 2 Effect of Gefapixant (MK-7264/AF-219) on Cough Reflex Sensitivity in Healthy and Chronic Cough Participants (MK-7264-014) Completed
Phase 2 Refractory Chronic Cough Improvement Via NAL ER (RIVER) Completed
Phase 2 A Clinical Trial to Evaluate the Safety and Efficacy in Subjects With Chronic Cough Completed
N/A Sham CPAP vs. Straight CPAP for Chronic Cough Completed

Showing the 19 most-cited and recently-updated of 19 trials. Browse the full registry →

Trial data sourced from ClinicalTrials.gov. Counts describe the research landscape and are not a treatment recommendation. Informational only — not medical advice.

What the trials found Updated — new results For clinicians

Chronic cough: what the trials found

Gefapixant has demonstrated significant improvements in cough symptoms and related quality of life measures across multiple trials. Specifically, it significantly improved Leicester Cough Questionnaire (LCQ) total scores [5, 6] and reduced cough severity as measured by Visual Analogue Scale (VAS) ¹². One study also reported a significant reduction in cough-induced stress urinary incontinence episodes ⁷.

Gefapixant has shown consistent efficacy in reducing objective cough frequencies. Significant reductions were observed in daytime objective cough frequency ¹², awake objective cough frequency in specific cohorts ¹³, and 24-hour objective cough frequency at the 8-week mark ¹⁸. Additionally, Gefapixant significantly reduced cough reflex sensitivity to capsaicin as measured by both maximal cough response (Emax) and the tussive concentration required to achieve 50% of Emax ¹¹.

Other interventions show mixed or limited evidence for chronic cough. Mepolizumab did not show a statistically significant change in 24-hour or awake cough frequency at 14 weeks ². Placebo groups in large trials showed no statistically significant changes in objective cough frequencies over 12 to 24 weeks [3, 4].

Recent results — preliminary, needs further review

NAL ER demonstrated a significant reduction in 24-hour cough frequency at day 21 (p<0.0001), with approximately 78.9% of patients achieving a $\geq$30% reduction and 87.0% achieving a $\geq$75% reduction ¹.

For the clinician treating this condition

Gefapixant is associated with significant improvements in patient-reported outcomes (LCQ, VAS) and reductions in objective cough frequency across various time points [5, 6, 12, 13, 18].
Gefapixant has been shown to reduce the physiological sensitivity of the cough reflex to capsaicin ¹¹.
NAL ER showed significant reduction in cough frequency and high responder rates at week 3 ¹.

AI synthesis of 7 cited trials, updated Jun 29, 2026. Informational only — not medical advice; trial data sourced from ClinicalTrials.gov. How we use AI.