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Active, not recruitingNCT04691154Updated Apr 1, 2026

A Phase 3 Study to Evaluate the Safety and Tolerability of L606 in Subjects With PAH or PH-ILD

A Phase 3 interventional study of L606 inhalation suspension in Pulmonary Arterial Hypertension and Pulmonary Hypertension Due to Lung Diseases, sponsored by Liquidia Technologies, Inc.. Active, not recruiting at 8 sites in United States. Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-04-01.

Sponsored by Liquidia Technologies, Inc. · Phase 3, Interventional, and Treatment

Phase
Phase 3
Study type
Interventional
Enrollment
28
Allocation
Not applicable
Ages
18 Years to 80 Years
Sex
All
01

Study summary

This Phase 3, 2-part, open-label, multicenter study aims to demonstrate the safety and tolerability of L606 in patients with PAH or PH-ILD. The study will determine the short-term and long-term safety and tolerability of L606 in this patient population.

Read the detailed description

This Phase 3, 2-part, open-label, multicenter study aims to demonstrate the safety and tolerability of repeated doses of L606 in patients with PAH or PH-ILD.

Cohort A: Subjects with PAH or PH-ILD receiving prior stable doses of Tyvaso and willing to switch to L606.

Cohort B: Subjects with PAH (not initially on prostacyclin therapy) who are likely to receive clinical benefit from inhaled treprostinil based on the opinion of the investigator.

Cohort A subjects will sequentially participate in the Main Study Period (MSP) for 2 weeks and the Open Extension Period (OEP) for 46 weeks. Cohort B subjects will sequentially participate in the MSP for 12 weeks and the OEP for 36 weeks.

02

Conditions studied

  • Pulmonary Arterial Hypertension
  • Pulmonary Hypertension Due to Lung Diseases

Keywords

  • treprostinil
  • Pulmonary Arterial Hypertension
  • inhalation
  • Pulmonary Hypertension Due to Lung Diseases
03

In context

Pulmonary Arterial Hypertension

699 studies on the registry are indexed under Pulmonary Arterial Hypertension; 140 are open to participants now.

This study's enrollment of 28 is below the median of 40 across 477 interventional studies indexed under Pulmonary Arterial Hypertension.

Browse Pulmonary Arterial Hypertension studies →

Lead sponsor

Liquidia Technologies, Inc. is the lead sponsor of 10 studies on the registry; 3 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 80 Years
Sexes eligible
All
Accepts healthy volunteers
No

Eligibility criteria

Key Inclusion Criteria:

  1. Males and females ≥18 and ≤80 years of age.

  2. Diagnosed with

    1. PAH belonging to at least 1 of the following subgroups of Group 1 pulmonary hypertension (PH) per European Society of Cardiology/European Respiratory Society Guidelines for the diagnosis and treatment of PH at least 1 year prior to screening. or
    2. PH-ILD Group 3 European Society of Cardiology/European Respiratory Society Guidelines for the diagnosis and treatment of PH. Subjects with Group 3 PH that is not related to underlying ILD are not eligible.

  3. Subjects with PAH: Documentation of having PAH as confirmed by RHC meeting the following criteria:

    i. Mean PAP >20 mmHg. ii. Pulmonary arterial wedge pressure ≤15 mmHg. iii. Pulmonary vascular resistance >3 Wood units. Subjects with PH-ILD: Confirmation of the underlying ILD must be based on HRCT imaging with demonstration of diffuse parenchymal lung disease and documented by the Investigator or radiology report. Subjects may have any form of ILD or CPFE.

  4. functional class II, III, or IV at the screening visit.
  5. Can complete a screening 6MWD of ≥150 meters
  6. For subjects with PAH: >65% of predicted and /FVC ratio >65% at screening. For subjects with PH-ILD: >40% of predicted and FEV1/FVC ratio >70% at screening.

Key Exclusion Criteria:

  1. of ≤45% on a historical echocardiogram.
  2. History of sleep apnea, or left-sided heart disease (including but not limited to aortic or mitral valve disease, pericardial constriction, restrictive or congestive cardiomyopathy, or coronary artery disease) per investigator's discretion.
  3. Experienced an acute exacerbation of disease or hospitalization for any reason within 30 days of signing the ICF or prior to baseline.
  4. Musculoskeletal disorder (eg, arthritis affecting the lower limbs, recent hip or knee joint replacement) or any disease that would likely be the primary limit to ambulation or subject is connected to a machine that is not portable enough to allow for a 6MWT.
Terms in these criteria, in plain language(3)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

NYHA class (heart failure)

The New York Heart Association’s four classes of how much heart failure limits physical activity.

I
No limits: ordinary activity causes no undue tiredness or breathlessness.
II
Slight limits: comfortable at rest, ordinary activity causes symptoms.
III
Marked limits: comfortable at rest, less than ordinary activity causes symptoms.
IV
Symptoms even at rest; any activity makes them worse.

Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.

FEV1

From a breathing test (spirometry): how much air you can blow out in the first second. Often given as a percentage of what is expected for your age, height and sex.

LVEF (left ventricular ejection fraction)

The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.

05

Study design

Phase
Phase 3
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
28 participants (actual)

Study arms

  • Experimental
    L606

    Combination Product: L606 inhalation suspension

Interventions

  • Combination productL606 inhalation suspension

    L606 inhalation suspension

06

What researchers measure

Primary outcomes

  1. Safety/Tolerability assessed by incidence of treatment-emergent AEs/SAEs

    (MSP for Cohort A): Proportion of patients with PAH or PH-ILD on a stable Tyvaso dose who would develop treatment-emergent AEs/SAEs after switching to L606 dosing for up to 2 weeks during MSP.

    Time frame: 2 weeks

  2. Safety/Tolerability assessed by incidence of treatment-emergent AEs/SAEs

    (MSP for Cohort B): Proportion of patients with PAH (not initially on prostacyclin therapy) who would develop treatment-emergent AEs/SAEs during 12 weeks of the MSP with titration on twice daily L606.

    Time frame: 12 weeks

  3. Safety/Tolerability assessed by incidence of treatment-emergent AEs/SAEs (long-term)

    (OEP for Cohorts A and B): Proportion of subjects with PAH or PH-ILD, choosing to continue twice daily L606 dosing for up to 48 weeks, who would develop treatment emergent AEs/SAEs up to 48 hours after the last dose.

    Time frame: 48 weeks

07

Study locations

8 sites
08

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Ran from Aug 2021 to primary completion in Mar 2025, 43 months.

Of 43 industry-sponsored phase 3 interventional studies under Pulmonary Arterial Hypertension, half reached primary completion within 50 months of starting (the median), counting those still running; a quarter within 31 and three quarters within 83. This study's 43 months is below that.

Counting every sponsor, half of 49 studies reached it within 50 months; a quarter within 31 and three quarters within 83.

How these figures are worked out, and which studies are left out of them.

Registered
Dec 21, 2020
First posted
Dec 31, 2020
StartActual
Aug 1, 2021
Primary completionActual
Mar 20, 2025
CompletionEst.
Mar 31, 2031
Results delay requested
Mar 18, 2026
Last update
Apr 1, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Apr 1, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
09

Registry details

Key details

Study ID
NCT04691154
Lead sponsor
Liquidia Technologies, Inc.
Collaborators
PPD Development, LP
Responsible party
Sponsor
First posted
Dec 31, 2020
Start date
Aug 1, 2021
Primary completion
Mar 20, 2025
Completion
Mar 31, 2031 (estimated)
Last update
Apr 1, 2026

Oversight

Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is active, not recruiting, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.

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