for people ages 40-75 (full criteria)
at San Francisco, California and other locations
study started
estimated completion
Principal Investigator
by Steven Hays
Headshot of Steven Hays
Steven Hays



The purpose of this research is to study an investigational medical device that is designed to produce lung volume reduction in diseased areas of the lungs in patients with severe emphysema.

Official Title

Lung Function Improvement After Bronchoscopic Lung Volume Reduction With Pulmonx Endobronchial Valves Used in Treatment of Emphysema


The Pulmonx Zephyr Endobronchial Valve (EBV) is an implantable bronchial valve intended to decrease volume in targeted regions of the lung. It is indicated for the treatment of patients with severe emphysema. The EBV are placed in the diseased region of the lung using bronchoscopy. Bronchoscopy is a way to access the lungs using a small tube with a camera on the end. As the diseased region of the lung shrinks in size, healthier regions may expand and function more efficiently, resulting in improved breathing.

The LIBERATE Study is a clinical trial with two groups. Participants are assigned at random to the 'Treatment' group or to the 'Control' group. The 'Treatment' group will receive the Zephyr Endobronchial Valve (EBV) in combination with optimal medical therapy. The 'Control' group will receive optimal medical therapy alone. For every three participants in the study, two will go into the 'Treatment' group and one will go into the 'Control' group.

It is hypothesized that after placement of the EBV, lung function will be improved as compared to standard medical therapy alone.

Based on the 12-month follow up data from the LIBERATE Study, the Zephyr Endobronchial Valve System was approved by the FDA for the treatment of severe emphysema in June 2018. Following this PMA approval, and in agreement with the FDA, the ongoing long term follow-up (out to 5 years) of patients in the LIBERATE Study will now be conducted as a Post-approval study under the auspices of the "LIBERATE Extension Study". This is an administrative change with absolutely no change to the design or conduct of the study and, therefore has no material impact to the study participants or the study sites. All annual follow-up visits and evaluations are per the original LIBERATE Study protocol. Reporting to the FDA will be as the LIBERATE Extension Study.


Emphysema, endobronchial valve, treatments, pulmonary rehabilitation, lung volume reduction, Pulmonary Emphysema, EBV, Optimal Medical Management


You can join if…

Open to people ages 40-75

  • Clinical and radiological evidence of emphysema
  • Nonsmoking for 4 months prior to screening interview
  • BMI less than 35 kg/m2
  • Stable on current medication regimen
  • Forced expiratory volume in one second (FEV1) between 15% and 45% of predicted value
  • Residual Volume less than 175% predicted (determined by body plethysmography)
  • Little or no collateral ventilation (CV-) as determined using the Chartis System

You CAN'T join if...

  • Had two or more hospitalizations over the last year for a COPD exacerbation
  • Had two or more hospitalizations over the last year for pneumonia
  • Had a prior lung transplant, lung volume reduction surgery, bullectomy or lobectomy
  • Had a heart attack or congestive heart failure within the last 6 months
  • Have heart arrhythmia
  • Is alpha-1 antitrypsin deficient


  • UCSF
    San Francisco California 94143 United States
  • Stanford University
    Stanford California 94507 United States

Lead Scientist at UCSF

  • Steven Hays
    Dr. Steven Hays, a pulmonologist, is medical director of the UCSF Lung Transplant Program, which is known for accepting patients with complex conditions while maintaining superior survival rates. His expertise is in caring for patients with end-stage lung disease who proceed through the lung transplant process.


in progress, not accepting new patients
Start Date
Completion Date
Pulmonx Corporation
Study Type
About 190 people participating
Last Updated