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Testing a new inhaled treatment for pulmonary hypertension in COPD patients

A Phase 2a Randomized, Placebo-Controlled Clinical Study to Evaluate the Efficacy and Safety of MK-5475 in Adults With Pulmonary Hypertension Associated With Chronic Obstructive Pulmonary Disease

PHASE2 · Merck Sharp & Dohme LLC · NCT05612035

This study is testing if a new inhaled treatment can help people with pulmonary hypertension related to COPD walk further and feel better after 24 weeks.

Quick facts

PhasePHASE2
Study typeInterventional
Enrollment120 (estimated)
Ages40 Years to 85 Years
SexAll
SponsorMerck Sharp & Dohme LLC (industry)
Locations84 sites (San Francisco, California and 83 other locations)
Trial IDNCT05612035 on ClinicalTrials.gov

What this trial studies

This study evaluates the efficacy and safety of frespaciguat, an inhaled sGC stimulator, in adults suffering from pulmonary hypertension associated with chronic obstructive pulmonary disease (PH-COPD). Participants will be randomly assigned to receive either frespaciguat or a placebo, with the primary outcome being the distance they can walk in six minutes after 24 weeks of treatment. The study aims to determine if frespaciguat can improve exercise capacity in this patient population. It involves careful monitoring of participants' health and adherence to specific inclusion and exclusion criteria.

Who should consider this trial

Good fit: Ideal candidates are adults diagnosed with Group 3.1 pulmonary hypertension due to chronic obstructive pulmonary disease, who meet specific hemodynamic and functional criteria.

Not a fit: Patients with other forms of pulmonary hypertension or those not meeting the inclusion criteria may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly improve the exercise capacity and quality of life for patients with PH-COPD.

How similar studies have performed: While this approach is novel in the context of PH-COPD, similar studies targeting pulmonary hypertension have shown promising results.

Eligibility criteria

Show full inclusion / exclusion criteria 
The key inclusion and exclusion criteria include but are not limited to the following:

Inclusion Criteria:

* Has Group 3.1 pulmonary hypertension chronic obstructive pulmonary disease (PH-COPD) as defined by the Clinical Classification of Pulmonary Hypertension.
* Has a right heart catheterization (RHC) at screening or historical RHC within 12 months before screening that meets hemodynamic criteria.
* Has a physician diagnosis of obstructive lung disease on pulmonary function testing (PFT) performed at screening.
* Has a WHO Functional Class assessment of Class II to IV.
* If on supplemental oxygen, the regimen must be stable.
* Has stable and optimized chronic, baseline COPD-specific therapy.
* If on PDE5 inhibitor, has stable concomitant use (initiated at least 3 months prior to randomization and no change in drug or dosage for at least 3 months prior to randomization) and changes to PDE5 inhibitor dosing is not anticipated during the 24 week Base Period.
* If on antihypertensives and/or a diuretic regimen has stable concomitant use.
* If on anticoagulants has stable concomitant use.
* Is of any sex/gender from 40 to 85 years of age inclusive.
* Female is not pregnant or breastfeeding, and is not of childbearing potential or uses acceptable contraceptive method or abstains from sexual intercourse, or has a negative highly sensitive pregnancy test within 24 hours before the first dose of study intervention, or whose history and sexual activity has been reviewed by the investigator.

Exclusion criteria:

* Has Group 1 pulmonary arterial hypertension (PAH), Groups 2, 4 or 5 pulmonary hypertension (PH).
* Has non-COPD related Group 3 PH.
* Has evidence of untreated more than mild obstructive sleep apnea.
* Has significant left heart disease.
* Expects to receive a lung and/or heart transplant from screening through the end of the 24 week Base Period.
* Has evidence of a resting oxygen saturation (SpO2) \< 88%.
* Has experienced a moderate or severe COPD exacerbation within 2 months before randomization.
* Has experienced right heart failure within 2 months before randomization.
* Has uncontrolled tachyarrhythmia.
* Has acute coronary syndrome, undergone coronary artery bypass graft, or percutaneous coronary intervention within 2 months before randomization.
* Has evidence of significant chronic renal insufficiency.
* Has evidence of chronic liver disease, portal hypertension, cirrhosis, or hepatic abnormalities.
* Initiated a pulmonary rehabilitation program within 2 months before randomization.
* Has impairments that limit the ability to perform 6MWT.
* Has history of cancer.
* Is a user of illicit drugs or has a recent history of drug/alcohol abuse or dependence.
* Has used PAH-specific therapies within 2 months of randomization.

Where this trial is running

San Francisco, California and 83 other locations

+34 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Pulmonary Hypertension, Chronic Obstructive Pulmonary Disease

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.