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Clinical Trials Registry

Our Clinical Trials Registry is a free service to connect physicians to clinical trials in respiratory disease conducted by participating pharmaceutical companies. Clinical trials power medical progress, allowing researchers to test new ways to prevent, detect, and treat respiratory disease. Without clinical trials, treatment advancements would be significantly hampered.

Ongoing groundbreaking research could have a measurable impact on patient care, but a lack of clinical trial participants is significantly slowing research and threatening the development of new treatments. Recruiting and retaining trial participants are the greatest challenges to developing the next generation of treatment options.

Participation in clinical trials provides an opportunity to advance and accelerate medical research and contribute to an improved health outlook for future generations. Use our registry to get information on how you can be involved in a clinical trial.



BAY63-2521 Replacing PDE-5i therapy evaluated Against Continued PDE-5i therapy).

Company: Bayer AG
Clinical trial description:  A prospective, randomized, international, multicenter, double-arm, controlled, open-label, Phase IV study of BAY63-2521 in patients with pulmonary arterial hypertension (PAH) who are on a stable dose of phosphodiesterase-5 inhibitors (PDE-5i) with or without endothelin receptor antagonist (ERA), but not at treatment goal (defined as being World Health Organization Functional Class III and having a 6 Minute Walking Distance test between 165 m and 440 meters).


Type of participant needed:

  • Male and female patients aged 18 to 75 years with symptomatic Pulmonary Arterial Hypertension: pulmonary vascular resistance > 400 dyn*sec*cm-5 (5 Wood units), mean pulmonary artery pressure ≥ 25 mmHg, and pulmonary capillary wedge pressure (PCWP) ≤ 15 mmHg on right heart catheterization within 12 months prior to screening or PCWP can be replaced by left ventricular end-diastolic pressure ≤ 15 mmHg
  • PAH of the following types: Idiopathic, hereditary, drug/ toxin induced, associated with PAH due to Connective tissue disease, Congenital heart disease, but only if the patient underwent surgical repair more than one year before enrolment, portal hypertension with liver cirrhosis
  • Stable doses of a PDE-5i and ERA combination therapy or on stable PDE-5i monotherapy 6 weeks prior to and at randomization but not at treatment goal (tadalafil 20 to 40 mg once daily or sildenafil at least 60 mg daily dose)
  • World Health Organization Functional Class III at screening and at randomization
  • 6 Minute Walking Distance test between 165 m and 440 meters at screening and at randomization
  • Patients may be excluded if they have relevant obstructive and restrictive or other lung diseases. Exclusion criteria also include cardiovascular conditions such as left ventricular disease, coronary heart disease or stroke within previous 3 months.

Posted: August 16, 2017

Learn more about this trial


The American College of Chest Physicians (CHEST), in furtherance of its mission of advancing research, has established this page to provide a list of clinical trials seeking individuals to serve as principal investigators or to otherwise participate. CHEST has neither conducted an independent investigation of the nature, quality, scientific merit, or subject matter of the clinical trials, nor has it established criteria or preconditions for those trials being listed on this page. CHEST, its officers, regents, members, and employees are not recommending or endorsing the listed trials or the companies sponsoring trials and specifically disclaims liability for damages of any kind arising out of a member, health-care provider, or any other individual’s participation in a listed trial.