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


About this study

The purpose of this study with a 28-week Open-label Extension of BLU-5937 in adult (18 to 80 years of age) participants who have had persistent cough for ≥ 1 year prior to Screening, with a diagnosis of RCC defined as:

  • insufficient improvement in cough after treatment for the underlying condition(s) causing the cough; OR
  • unexplained cough for which an underlying condition has not been determined despite adequate investigation with diagnostic tests and trials of therapy.


Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. There is no guarantee that every individual who qualifies and wants to participate in a trial will be enrolled. Contact the study team to discuss study eligibility and potential participation.

Inclusion Criteria:

  • Capable of giving signed informed consent.
  • Refractory chronic cough (including unexplained chronic cough) for at least one year.
  • 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:

  • 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.
  • Diagnosis of Chronic Obstructive Pulmonary Disease (COPD), bronchiectasis, idiopathic pulmonary fibrosis or uncontrolled asthma.
  • Respiratory tract infection within 4 weeks before screening.
  • Laboratory confirmed Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection at screening.
  • History of malignancy in the last 5 years.
  • History of alcohol or drug abuse within the last 3 years.
  • Has a positive serologic test for human immunodeficiency virus (HIV), hepatitis B virus surface antigen, or hepatitis C virus.
  • Previous participation in a BLU-5937 trial.

Eligibility last updated 2/16/23. Questions regarding updates should be directed to the study team contact.

Participating Mayo Clinic locations

Study statuses change often. Please contact the study team for the most up-to-date information regarding possible participation.

Mayo Clinic Location Status Contact

Rochester, Minn.

Mayo Clinic principal investigator

Vivek Iyer, M.D., M.P.H.

Open for enrollment

Contact information:

Sue Ann Donlinger

(507) 284-9259


More information


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