For Healthcare Professionals

A 24-Week Study of the Efficacy and Safety of BLU-5937 in Adults With Refractory Chronic Cough (CALM-2)


About the study

This is a randomized, double-blind, placebo-controlled, parallel-arm, Phase 3 study of BLU-5937 in participants with Refractory Chronic Cough (RCC).

Who can take part

You may be eligible to participate in the study if you meet the following criteria:


Inclusion Criteria:

  1. Capable of giving signed informed consent
  2. Refractory chronic cough (including unexplained chronic cough) for at least one year
  3. Women of child-bearing potential must use a highly effective contraception method during the study and for at least 14 days after the last dose


Exclusion Criteria:

  1. Current smoker/vaper (all forms of smoking and inhaled substances, including , cannabis/tobacco smoke and nicotine vapors) or individuals who have given up smoking within the past 6 months, or those with >20 pack-year smoking history
  2. Diagnosis of Chronic Obstructive Pulmonary Disease (COPD), bronchiectasis, idiopathic pulmonary fibrosis or uncontrolled asthma
  3. Respiratory tract infection within 4 weeks before screening
  4. Laboratory confirmed Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection at screening
  5. History of malignancy in the last 5 years
  6. History of alcohol or drug abuse within the last 3 years
  7. Has a positive serologic test for human immunodeficiency virus (HIV), hepatitis B virus surface antigen, or hepatitis C virus.
  8. Previous participation in a BLU-5937 trial
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Study Locations

Enter your ZIP code/Postal code/PIN code to locate study sites near you:

How to Apply

Contact the study center to learn if this study is a good match for you.

Study’s details


Refractory Chronic Cough

Age (in years)

18 - 80


Phase 3

Participants needed


Est. Completion Date

Jul 31, 2025

Treatment type



Bellus Health Inc identifier


Study number


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