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Study on the Effects of Camlipixant in Adults with Refractory or Unexplained Chronic Cough

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying a condition known as Refractory Chronic Cough, which includes cases of Unexplained Chronic Cough. This condition is characterized by a persistent cough that does not respond to standard treatments and has no identifiable cause. The trial will evaluate a new treatment called BLU-5937, which contains the active substance Camlipixant. This medication is taken in the form of a tablet.

The purpose of the study is to assess the effectiveness and safety of BLU-5937 compared to a placebo in reducing the frequency of coughing over a 24-hour period. Participants in the study will be randomly assigned to receive either the medication or a placebo. The study will last for 52 weeks, with an option for participants to continue in an open-label extension, where all participants can receive BLU-5937 if they choose.

Throughout the study, participants will be monitored to ensure their safety and to track any changes in their cough frequency. The study aims to provide valuable information on how well BLU-5937 works in managing chronic cough and its safety profile over the course of the treatment period.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Randomization and initial assessment

    Upon joining the study, participants are randomly assigned to receive either the study medication, BLU-5937, or a placebo. This process is double-blind, meaning neither the participant nor the researchers know which treatment is being administered.

    An initial assessment is conducted to establish baseline cough frequency over a 24-hour period using a cough monitor.

  2. Step 2

    Medication administration

    Participants take the assigned medication orally in the form of a tablet. The tablets are round, biconvex, and white to off-white in color.

    The medication is taken as prescribed by the study protocol, with specific dosage and frequency determined by the study design.

  3. Step 3

    Monitoring and follow-up

    Participants are monitored regularly to assess the effect of the medication on cough frequency. This includes periodic evaluations at specified intervals, such as at Week 12.

    Safety assessments are conducted throughout the study to monitor for any adverse effects or serious adverse events.

  4. Step 4

    Open-label extension

    After the initial 52-week period, participants may enter an open-label extension phase where all participants receive BLU-5937.

    This phase allows for continued monitoring of the medication's long-term effects and safety.

  5. Step 5

    Completion and final assessment

    At the end of the study, a final assessment is conducted to evaluate the overall impact of the medication on cough frequency and participant safety.

    Participants are provided with information regarding the study's findings and any relevant follow-up care.

Who can join the trial?

5 criteria

  • Must be between 18 and 80 years old.
  • Must be able to understand and agree to the written consent form.
  • Must have been diagnosed with **Refractory Chronic Cough** (a cough that doesn't go away) for at least 1 year before the study starts.
  • Must meet the specific criteria for how often they cough.
  • If female, must not be pregnant or breastfeeding. Must either not be able to have children or agree to use birth control if they can have children.

Who cannot join the trial?

7 criteria

  • Patients who have a cough caused by a known medical condition other than **Refractory Chronic Cough** or **Unexplained Chronic Cough** cannot participate. **Refractory Chronic Cough** means a cough that does not get better with treatment.
  • Patients who are currently participating in another clinical trial are not eligible.
  • Patients who have a history of drug or alcohol abuse may be excluded.
  • Patients with certain medical conditions that could interfere with the study may not be allowed to join.
  • Patients who are pregnant or breastfeeding cannot take part in the study.
  • Patients who have had a recent respiratory infection may be excluded.
  • Patients who are unable to comply with the study procedures or follow-up visits may not be eligible.
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Investigated drugs

BLU-5937 is a medication being studied for its potential to reduce the frequency of coughing in adults who have a persistent cough that does not have a clear cause or does not respond to usual treatments. The trial aims to see how well this medication works over a 24-hour period and to ensure it is safe for use over a longer term, up to 52 weeks.

What is already known about the treatment

BLU-5937 – This medication is administered orally and is currently being studied in clinical trials for its effectiveness in treating refractory chronic cough, including unexplained chronic cough. It is in the advanced stages of clinical research, specifically a Phase 3 trial, which evaluates its efficacy and safety over a 52-week period. The main therapeutic indication for BLU-5937 is to reduce the frequency of chronic coughs that do not respond to standard treatments. At the molecular level, it works by selectively blocking the P2X3 receptor, which is involved in the cough reflex pathway. BLU-5937 is classified pharmacologically as a P2X3 receptor antagonist.

Investigated diseases

Refractory Chronic Cough – This condition is characterized by a persistent cough that lasts for more than eight weeks and does not respond to standard treatments. It can be caused by various underlying issues, but in some cases, the exact cause remains unknown, leading to a diagnosis of unexplained chronic cough. The cough can be disruptive to daily life, affecting sleep and social interactions. It often requires a comprehensive evaluation to rule out other potential causes. The condition can be frustrating for patients due to its persistent nature and the difficulty in finding effective relief.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-513460-26-00Protocol codeBUS-P3-01Estimated enrolment867 patientsSponsorBellus Health Inc.

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