Study LTI-401 is an open-label, multicenter study which will evaluate the safety and tolerability of LIQ861 in subjects who have WHO Group 1 & 3 PH.

Open-label, multicenter study which will evaluate the safety and tolerability of LIQ861 in subjects who have WHO Group 1 & 3 PH.

Cohort A will include approximately 60 subjects who have WHO Group 3 Pulmonary Hypertension associated with interstitial lung disease (PH-ILD)

Cohort B will include approximately 20 subjects who have WHO Group 3 PH-ILD, have been on protocol specified dosing of inhaled treprostinil QID, not at treatment goal, and able to transition to LIQ861.

The primary objective of this study is to evaluate the safety and tolerability of LIQ861 in subjects with WHO Group 1 & 3 Pulmonary Hypertension (PH).

Cohort A Key Inclusion Criteria:

1. Males or Females between 18 years to 80 years of age.

2. Has a confirmed diagnosis of WHO Group 3 PH-ILD based on CT chest imaging performed, which demonstrates evidence of diffuse parenchymal lung disease and FEV1/FVC (absolute values) ≥ 70% and are required to have evidence of pulmonary hypertension (PH) as demonstrated from right heart catheterization (RHC) with the following hemodynamic parameters.

   1. i) Pulmonary vascular resistance (PVR) ≥ 3 Wood Units (WU) and ii) Pulmonary capillary wedge pressure (PCWP) of ≤ 15 mmHg and iii) A mean pulmonary arterial pressure (mPAP) of ≥ 30 mmHg.

      OR

   2. An exploratory subset of subjects with ILD: i) Pulmonary vascular resistance (PVR) ≥ 3 Wood Units (WU) and ii) Pulmonary capillary wedge pressure (PCWP) of ≤ 15 mmHg and iii) A mean pulmonary arterial pressure (mPAP) of ≥ 21 mmHg.

3. 6-minute walk distance of ≥ 125 meters

Cohort A Key Exclusion Criteria:

A Subject is not eligible for inclusion in the study if any of the following criteria apply:

1. PH in the Updated WHO Classification Groups 1, 2, 4, or 5.
2. History of hemodynamically significant left-sided heart disease.
3. Exacerbation of underlying lung disease or active pulmonary or upper respiratory infections.
4. Initiation of pulmonary rehabilitation.

Cohort B Key Inclusion Criteria

1. Male or Females between 18 years to 75 years of age at Screening.

2. Has a diagnosis of WHO Group 3 PH-ILD confirmed with CT chest imaging performed at the screening visit, which demonstrates evidence of diffuse parenchymal lung disease and FEV1/FVC (absolute values) ≥70%. Subjects are required to have evidence of pulmonary hypertension (PH) as demonstrated from right heart catheterization (RHC) with the following documented parameters:

   1. Pulmonary vascular resistance (PVR) ≥3 Wood Units (WU) and
   2. Pulmonary capillary wedge pressure (PCWP) of ≤ 15 mmHg and
   3. A mean pulmonary arterial pressure (mPAP) of ≥ 25 mmHg

3. Subjects must be on protocol specified dose of inhaled treprostinil QID not at treatment goal, and able to transition from their prescribed dose of inhaled Treprostinil therapy to LIQ861.

4. 6-minute walk distance of ≥ 200 meters

Cohort B Key Exclusion Criteria

1. PH in the Updated WHO Classification Groups 1, 2, 4, or 5.
2. Inability to titrate inhaled treprostinil above 5 breaths (Tyvaso®) or above 16 mcg Tyvaso DPI®.
3. History of Bronchospasm with Tyvaso or Tyvaso DPI.
4. History of persistent moderate asthma or severe asthma.
5. History of hemodynamically significant left-sided heart disease.
6. Exacerbation of underlying lung disease or active pulmonary or upper respiratory infections.

Subject with PH-ILD