A Phase 3 Study to Evaluate the Safety and Efficacy L606 in Participants With PH-ILD (Re-Spire)

June 1, 2026 updated by: Liquidia Technologies, Inc.

A Phase 3, Multicenter, Randomized, Double-Blinded, Placebo-Controlled Study to Evaluate the Safety and Efficacy of L606 (Treprostinil Liposome Inhalation Suspension) in Participants With Pulmonary Hypertension Associated With Interstitial Lung Disease (WHO Group 3)

The purpose of this study is to find out if L606 is safe and if it helps people with high blood pressure in the lungs (pulmonary hypertension) caused by interstitial lung disease (PH-ILD, WHO Group 3). One of the main ways the study will check this is by seeing if people can walk further in six minutes (called the "six-minute walk test"). Another important (secondary) goal is to see how long it takes for PH-ILD to get worse while people are taking L606. One way the study will measure this is by looking at the distance people walk at different times in the study on different doses of L606. Throughout the study, doctors will also closely monitor for any side effects people have to make sure L606 is safe. People who decide to join this study will be randomly (like tossing a coin) placed into one of two groups: one group will get L606 and the other group will get a placebo, which will look like L606 but will not contain any active medicine. At the end of the initial blinded portion of the study, study participants may have the opportunity to enroll in an open-label extension portion of the study where all participants will receive L606.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

344

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Germany
      • Giessen, Germany, 35392
        • Recruiting
        • Universitätsklinikum Giessen und Marburg - Standort Giessen
        • Contact:
  • Latvia
      • Riga, Latvia, LV-1002
        • Recruiting
        • Pauls Stradins Clinical University Hospital
        • Contact:
  • United Kingdom
      • Plymouth, United Kingdom, PL6 8DH
        • Recruiting
        • University Hospitals Plymouth NHS Trust - Derriford Hospital
        • Contact:
  • United States
    • Florida
      • Tampa, Florida, United States, 33606
        • Recruiting
        • Tampa General Hospital
        • Contact:
    • Indiana
      • Indianapolis, Indiana, United States, 46260
        • Recruiting
        • St. Vincent Cardiovascular Research Institute
        • Contact:
    • Oregon
      • Bend, Oregon, United States, 97701

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Participant is between 18 years to 80 years old.
  • Has a confirmed diagnosis of ILD based on High Resolution Computed Tomography (HRCT) chest imaging.
  • Evidence of PH as demonstrated from Right Heart Catheterization (RHC) with the following hemodynamic parameters:
  • Pulmonary vascular resistance (PVR) ≥ 320 dynes.sec/cm5 (i.e. 4 Woods Units (WU)), and
  • Mean Pulmonary Artery Pressure (mPAP) of ≥ 25 mmHg, and
  • - Pulmonary capillary wedge pressure (PCWP) or Left-Ventricular End Diastolic Pressure (LVEDP) of ≤ 15 mmHg.
  • EV1/FVC (ratio) > 0.70.
  • 6-minute walk distance ≥ 150 meters

Exclusion Criteria:

  • PH in the updated WHO Classification Groups 1, 2, 4, or 5.
  • Has evidence of clinically significant left-sided heart disease as defined by echocardiography.
  • Participants with history of persistent/permanent or uncontrolled atrial fibrillation.
  • Participants with severe obstructive sleep apnea.
  • Has experienced exacerbation of underlying lung disease or active respiratory infection requiring antibiotics.
  • Initiation of pulmonary rehabilitation.

Note: Other protocol defined inclusion/exclusion criteria may apply.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: L606 (in combination with nebulizer)
Drug: L606
L606 is a liposomal version of treprostinil intended for delivery via oral inhalation using a study issued nebulizer.
Other Names:
  • Treprostinil Liposome Inhalation Suspension
Placebo Comparator: Placebo (in combination with nebulizer)
Drug: Placebo
Placebo will match L606 but contain no treprostinil.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Change from baseline in 6-minute walk distance (6MWD) as evaluated by the 6-minute walk test (6MWT)
Time Frame: 16 weeks
16 weeks

Secondary Outcome Measures

Outcome Measure
Time Frame
Change from baseline in 6-minute walk distance (6MWD) as evaluated by the 6-minute walk test (6MWT)
Time Frame: 16 weeks
16 weeks
Time to first occurrence of: -Death -Hospitalization due to a cardio-pulmonary indication related to underlying disease -Lung transplant -Decrease in 6MWD > 15% from Baseline related to disease under study at 2 consecutive visits >1 week apart
Time Frame: 24 weeks
24 weeks
Change from baseline in 6-minute walk distance (6MWD) as evaluated by the 6-minute walk test (6MWT)
Time Frame: 24 weeks
24 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Liquidia Technologies, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 23, 2026

Primary Completion (Estimated)

July 1, 2029

Study Completion (Estimated)

December 1, 2031

Study Registration Dates

First Submitted

December 11, 2025

First Submitted That Met QC Criteria

December 11, 2025

First Posted (Actual)

December 16, 2025

Study Record Updates

Last Update Posted (Actual)

June 2, 2026

Last Update Submitted That Met QC Criteria

June 1, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • L606-301

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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